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Sample records for highly ordered mesoporous

  1. Electrochemical Hydrogen Storage in a Highly Ordered Mesoporous Carbon

    Directory of Open Access Journals (Sweden)

    Dan eLiu

    2014-10-01

    Full Text Available A highly order mesoporous carbon has been synthesized through a strongly acidic, aqueous cooperative assembly route. The structure and morphology of the carbon material were investigated using TEM, SEM and nitrogen adsorption-desorption isotherms. The carbon was proven to be meso-structural and consisted of graphitic micro-domain with larger interlayer space. AC impedance and electrochemical measurements reveal that the synthesized highly ordered mesoporous carbon exhibits a promoted electrochemical hydrogen insertion process and improved capacitance and hydrogen storage stability. The meso-structure and enlarged interlayer distance within the highly ordered mesoporous carbon are suggested as possible causes for the enhancement in hydrogen storage. Both hydrogen capacity in the carbon and mass diffusion within the matrix were improved.

  2. Rapid removal of bisphenol A on highly ordered mesoporous carbon.

    Science.gov (United States)

    Sui, Qian; Huang, Jun; Liu, Yousong; Chang, Xiaofeng; Ji, Guangbin; Deng, Shubo; Xie, Tao; Yu, Gang

    2011-01-01

    Bisphenol A (BPA) is of global concern due to its disruption of endocrine systems and ubiquity in the aquatic environment. It is important, therefore, that efforts are made to remove it from the aqueous phase. A novel adsorbent, mesoporous carbon CMK-3, prepared from hexagonal SBA-15 mesoporous silica was studied for BPA removal from aqueous phase, and compared with conventional powdered activated carbon (PAC). Characterization of CMK-3 by transmission electron microscopy (TEM), X-ray diffraction, and nitrogen adsorption indicated that prepared CMK-3 had an ordered mesoporous structure with a high specific surface area of 920 m2/g and a pore-size of about 4.9 nm. The adsorption of BPA on CMK-3 followed a pseudo second-order kinetic model. The kinetic constant was 0.00049 g/(mg x min), much higher than the adsorption of BPA on PAC. The adsorption isotherm fitted slightly better with the Freundlich model than the Langmuir model, and adsorption capacity decreased as temperature increased from 10 to 40 degrees C. No significant influence of pH on adsorption was observed at pH 3 to 9; however, adsorption capacity decreased dramatically from pH 9 to 13.

  3. Ordered mesoporous carbide-derived carbon as new high performance electrode material in supercapacitors

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    Korenblit, Yair; Yushin, Gleb [Georgia Inst. of Technology, Atlanta, GA (United States); Rose, Marcus; Kockrick, Emanuel; Borchardt, Lars; Kaskel, Stefan [Technische Univ. Dresden (Germany); Kvit, Alexander [Wisconsin Univ., Madison, WI (United States)

    2010-07-01

    The preparation and application of templated ordered mesoporous CDC overcome the present limitations of slow intraparticle ion transport and poor control over the biomodal pore size distribution in the carbons currently used, and shows a route for further performance enhancement. The ordered mesoporous channels in SiC CDC serve as ion-highways and allow for very fast ionic transport into the bulk of the CDC particles, thus leading to an excellent frequency response and outstanding capacitance retention at high current densities. The ordered mesopores in SiC allow for a greatly increased specific surface area and specific capacitance of SiC CDC, nearly doubling the previously reported values. The use of CDC produced from other carbides, including mesoporous TiC or VC is expected to further enhance the energy storage characteristics of EDLC electrodes, while optimization of the mesopore size is expected to enhance the power characteristics of EDLC. (orig.)

  4. Highly ordered mesoporous cobalt oxide nanostructures: synthesis, characterisation, magnetic properties, and applications for electrochemical energy devices.

    Science.gov (United States)

    Wang, Guoxiu; Liu, Hao; Horvat, Josip; Wang, Bei; Qiao, Shizhang; Park, Jinsoo; Ahn, Hyojun

    2010-09-24

    Highly ordered mesoporous Co(3)O(4) nanostructures were prepared using KIT-6 and SBA-15 silica as hard templates. The structures were confirmed by small angle X-ray diffraction, high resolution transmission electron microscopy, and N(2) adsorption-desorption isotherm analysis. Both KIT-6 cubic and SBA-15 hexagonal mesoporous Co(3)O(4) samples exhibited a low Néel temperature and bulk antiferromagnetic coupling due to geometric confinement of antiferromagnetic order within the nanoparticles. Mesoporous Co(3)O(4) electrode materials have demonstrated the high lithium storage capacity of more than 1200 mAh g(-1) with an excellent cycle life. They also exhibited a high specific capacitance of 370 F g(-1) as electrodes in supercapacitors.

  5. Intermediate-range order in mesoporous silicas investigated by a high-energy X-ray diffraction technique

    International Nuclear Information System (INIS)

    Wakihara, Toru; Fan, Wei; Ogura, Masaru; Okubo, Tatsuya; Kohara, Shinji; Sankar, Gopinathan

    2008-01-01

    We perform a high-energy X-ray diffraction study comparing bulk amorphous silica with MCM-41 and SBA-15 that are representative mesoporous silicas prepared in basic and acidic conditions, respectively. It is revealed that mesoporous silicas, especially SBA-15, have less ordered structures and contain larger fractions of three- and four-membered rings than does bulk amorphous silica. (author)

  6. Amorphous Mn oxide-ordered mesoporous carbon hybrids as a high performance electrode material for supercapacitors.

    Science.gov (United States)

    Nam, Inho; Kim, Nam Dong; Kim, Gil-Pyo; Park, Junsu; Yi, Jongheop

    2012-07-01

    A supercapacitor has the advantages of both the conventional capacitors and the rechargeable batteries. Mn oxide is generally recognized one of the potential materials that can be used for a supercapacitor, but its low conductivity is a limiting factor for electrode materials. In this study, a hybrid of amorphous Mn oxide (AMO) and ordered mesoporous carbon (OMC) was prepared and characterized using X-ray diffraction, transmission electron microscopy, N2/77 K sorption techniques, and electrochemical analyses. The findings indicate that the electrochemical activities of Mn oxide were facilitated when it was in the hybrid state because OMC acted as a pathway for both the electrolyte ions and the electrons due to the characteristics of the ordered mesoporous structure. The ordered mesoporous structure of OMC was well maintained even after hybridization with amorphous Mn oxide. The electrochemical-activity tests revealed that the AMO/OMC hybrid had a higher specific capacitance and conductivity than pure Mn oxide. In the case where the Mn/C weight ratio was 0.75, the composite showed a high capacitance of 153 F/g, which was much higher than that for pure Mn oxide, due to the structural effects of OMC.

  7. Synthesis of partially graphitic ordered mesoporous carbons with high surface areas

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    Gao, Wenjun; Wan, Ying [Department of Chemistry, Key Laboratory of Resource Chemistry of Ministry of Education, Shanghai Normal University, Shanghai 200234 (China); Dou, Yuqian; Zhao, Dongyuan [Department of Chemistry, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University, Shanghai 200433 (China)

    2011-01-01

    Graphitic carbons with ordered mesostructure and high surface areas (of great interest in applications such as energy storage) have been synthesized by a direct triblock-copolymer-templating method. Pluronic F127 is used as a structure-directing agent, with a low-molecular-weight phenolic resol as a carbon source, ferric oxide as a catalyst, and silica as an additive. Inorganic oxides can be completely eliminated from the carbon. Small-angle XRD and N{sub 2} sorption analysis show that the resultant carbon materials possess an ordered 2D hexagonal mesostructure, uniform bimodal mesopores (about 1.5 and 6 nm), high surface area ({proportional_to}1300 m{sup 2}/g), and large pore volumes ({proportional_to}1.50 cm{sup 3}/g) after low-temperature pyrolysis (900 C). All surface areas come from mesopores. Wide-angle XRD patterns demonstrate that the presence of the ferric oxide catalyst and the silica additive lead to a marked enhancement of graphitic ordering in the framework. Raman spectra provide evidence of the increased content of graphitic sp{sup 2} carbon structures. Transmission electron microscopy images confirm that numerous domains in the ordered mesostructures are composed of characteristic graphitic carbon nanostructures. The evolution of the graphitic structure is dependent on the temperature and the concentrations of the silica additive, and ferric oxide catalyst. Electrochemical measurements performed on this graphitic mesoporous carbon when used as an electrode material for an electrochemical double layer capacitor shows rectangular-shaped cyclic voltammetry curves over a wide range of scan rates, even up to 200 mV/s, with a large capacitance of 155 F/g in KOH electrolyte. This method can be widely applied to the synthesis of graphitized carbon nanostructures. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  8. Self-assembled highly ordered ethane-bridged periodic mesoporous organosilica and its application in HPLC.

    Science.gov (United States)

    Huang, Lili; Lu, Juan; Di, Bin; Feng, Fang; Su, Mengxiang; Yan, Fang

    2011-09-01

    Monodisperse spherical periodic mesoporous organosilicas (PMOs) with ethane integrated in the framework were synthesized and their application as stationary phase for chromatographic separation is demonstrated. The ethane-PMOs were prepared by condensation of 1,2-bis(triethoxysilyl)ethane (BTSE) in basic condition using octadecyltrimethylammonium chloride (C(18)TMACl) as template and ethanol as co-solvent. The morphology and mesoporous structure of ethane-PMOs were controlled under different concentrations of sodium hydroxide (NaOH) and EtOH. The results of scanning electron microscopy (SEM), transmission electron microscopy (TEM), powder X-ray diffraction (XRD), nitrogen sorption measurement, Fourier transform infrared spectroscopy (FT-IR) and elemental analysis showed that ethane-PMOs have spherical morphology, uniform particle distribution, highly ordered pore structure, high surface area and narrow pore-size distribution. The column packed with these materials exhibits good permeability, high chemical stability and good selectivity of mixtures of aromatic hydrocarbons in normal phase high-performance liquid chromatography (HPLC). Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Morphology control of ordered mesoporous carbons for high capacity lithium sulfur batteries

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    Schuster, Joerg David

    2011-06-07

    The focus of this thesis concerns the morphology control of ordered mesoporous carbon (OMC) materials. Ordered mesoporous carbons with diverse morphologies, that are thin films, fibers - embedded in anodic alumina membranes and free-standing - or spherical nanoparticles, have been successfully prepared by soft-templating procedures. The mechanisms of structure formation and processing were investigated with in-situ SAXS measurements and their application in high capacity lithium-sulfur batteries was successfully tested in cooperation with Guang He and Linda Nazar from the University of Waterloo in Canada. The Li-S batteries receive increasing attention due to their high theoretical energy density which is 3 to 5 times higher than from lithium-ion batteries. For this type of battery the specific pore volume is crucial for the content of the active component (sulfur) in the cathode and therefore correlates with the capacity and gravimetric energy density of the battery. At first, mesoporous thin films with 2D-hexagonal structure were obtained through organic-organic self-assembly of a preformed oligomeric resol precursor and the triblock copolymer template Pluronic P123. The formation of a condensed-wall material through thermopolymerization of the precursor oligomers resulted in mesostructured phenolic resin films. Subsequent decomposition of the surfactant and partial carbonization were achieved through thermal treatment in inert atmosphere. The films were crack-free with tunable homogenous thicknesses, and showed either 2D-hexagonal or lamellar mesostructure. An additional, yet unknown 3D-mesostructure was also found. In the second part, cubic and circular hexagonal mesoporous carbon phases in the confined environment of tubular anodic alumina membrane (AAM) pores were obtained by self-assembly of the mentioned resol precursor and the triblock copolymer templates Pluronic F127 or P123, respectively. Casting and solvent-evaporation were also followed by

  10. Highly crystalline mesoporous C{sub 60} with ordered pores. A class of nanomaterials for energy applications

    Energy Technology Data Exchange (ETDEWEB)

    Benzigar, Mercy R.; Joseph, Stalin; Ilbeygi, Hamid [Future Industries Institute (FII), Division of Information Technology Energy and Environment (DivITEE), University of South Australia, Adelaide, SA (Australia); Park, Dae-Hwan; Talapaneni, Siddulu Naidu [Global Innovative Center for Advanced Nanomaterials (GICAN), Faculty of Engineering and Built Environment, The University of Newcastle, Callaghan, NSW (Australia); Sarkar, Sujoy; Chandra, Goutam; Umapathy, Siva; Srinivasan, Sampath [Department of Inorganic and Physical Chemistry and Department of Instrumentation and Applied Physics, Indian Institute of Science (IISc), Bangalore (India); Vinu, Ajayan [Future Industries Institute (FII), Division of Information Technology Energy and Environment (DivITEE), University of South Australia, Adelaide, SA (Australia); Global Innovative Center for Advanced Nanomaterials (GICAN), Faculty of Engineering and Built Environment, The University of Newcastle, Callaghan, NSW (Australia)

    2018-01-08

    Highly ordered mesoporous C{sub 60} with a well-ordered porous structure and a high crystallinity is prepared through the nanohard templating method using a saturated solution of C{sub 60} in 1-chloronaphthalene (51 mg mL{sup -1}) as a C{sub 60} precursor and SBA-15 as a hard template. The high solubility of C{sub 60} in 1-chloronaphthalene helps not only to encapsulate a huge amount of the C{sub 60} into the mesopores of the template but also supports the oligomerization of C{sub 60} and the formation of crystalline walls made of C{sub 60}. The obtained mesoporous C{sub 60} exhibits a rod-shaped morphology, a high specific surface area (680 m{sup 2} g{sup -1}), tuneable pores, and a highly crystalline wall structure. This exciting ordered mesoporous C{sub 60} offers high supercapacitive performance and a high selectivity to H{sub 2}O{sub 2} production and methanol tolerance for ORR. This simple strategy could be adopted to make a series of mesoporous fullerenes with different structures and carbon atoms as a new class of energy materials. (copyright 2018 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  11. Structural and surface properties of highly ordered mesoporous magnesium-aluminium composite oxides derived from facile synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Pan, Dahai, E-mail: pandahai@foxmail.com; Dong, Zhaoyang; He, Min; Chen, Wei; Chen, Shuwei; Yu, Feng; Fan, Binbin; Cui, Xingyu; Li, Ruifeng, E-mail: rfli@tyut.edu.cn

    2017-01-15

    Highly ordered mesoporous magnesium-aluminium composite oxides (denoted as OMMA-x) with a variety of n{sub Al}/n{sub Mg} ratios have been successfully synthesized via a facile strategy, and a salt effect was proposed to explain the formation mechanism. The incorporation of Mg can significantly improve the structural and surface properties of ordered mesoporous alumina (OMA) material. The resultant OMMA-x exhibited a much more ordered 2-D hexagonal mesostructure, a narrower pore size distribution, a higher specific surface area and pore volume, and a stronger basicity than those of OMA. More importantly, the highly homogeneous incorporation of Mg at the atomic level and the formation of framework Mg−O−Al bonds could effectively suppress the formation of crystalline alumina during the calcination process. As a result, OMMA-x demonstrated a superior thermal stability. For example, the ordered mesostructure of OMMA-8 could be well maintained with a high surface area of 182 m{sup 2}/g even after thermal treatment at 1000 °C. - Graphical abstract: A schematic procedure to illustrate the preparation of highly ordered mesoporous Mg-Al composite oxides (OMMA-x) with highly homogeneously dispersed Mg species and enhanced structural stability. - Highlights: • Mesoporous Mg-Al composite oxides with excellent structural and surface properties. • A highly homogeneous incorporation of Mg into the mesoporous framework of alumina. • A superior structural stability up to 1000 °C coupled with a large surface area. • A salt effect from the addition of Mg(NO{sub 3}){sub 2}·6H{sub 2}O to explain the formation mechanism.

  12. Controllable Fabrication of Ordered Mesoporous Bi2WO6 and Its High Photocatalytic Activity under Visible Light

    Directory of Open Access Journals (Sweden)

    Xueming Dang

    2014-01-01

    Full Text Available Ordered mesoporous Bi2WO6 was fabricated by nanocasting technique using SBA-15 as the template. The effect of the dosage of SBA-15 on the formation of the ordered structure and the photocatalytic ability of mesoporous Bi2WO6 was discussed. It was confirmed that the ordered mesoporous structure was obtained as the dosage of SBA-15 was 0.3 g. It was found that, compared to Bi2WO6, the RhB degradation rate with ordered mesoporous Bi2WO6 was enhanced under visible light (λ>400 nm by the photocatalytic measurements. The enhanced photocatalytic performance of ordered mesoporous Bi2WO6 was attributed to its particular ordered mesoporous structure which could increase the light-harvesting efficiency, reduce the recombination of the photogenerated charge carriers, and promote the surface reaction.

  13. Ordered mesoporous carbon/FeO(OH) composites for supercapacitors with high capacitive performance

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    Liao, H.; Zhao, J.; Tang, B.; Xu, J. [Shanghai Univ. of Engineering Science (China). College of Chemistry and Chemical Engineering

    2010-07-01

    In this study, ordered mesoporous carbon/FeO(OH) composites were synthesized using an incipient wetness impregnation method. X-ray diffraction (XRD), transmission electron microscopy (TEM), and nitrogen gas (N{sub 2}) adsorption/desorption analyses were used to characterize the morphology and microstructure of the composite samples. The analyses indicated that a new hydrate iron oxide was obtained for use as a low-cost composite electrode. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) analyses were conducted in 2 M KOH aqueous solutions in order to characterize the capacitor properties of the composite materials. The study showed that the highest special capacitance obtained by the composites was 486.27 F/g measured at 5 mV/s for an OMCL composite material containing 9.6 per cent FeO(OH). The capacitor properties of various amounts of FeO(OH) were also investigated.

  14. Highly efficient synthesis of ordered nitrogen-doped mesoporous carbons with tunable properties and its application in high performance supercapacitors

    Science.gov (United States)

    Liu, Dan; Zeng, Chao; Qu, Deyu; Tang, Haolin; Li, Yu; Su, Bao-Lian; Qu, Deyang

    2016-07-01

    Nitrogen-doped ordered mesoporous carbons (OMCs) have been synthesized via aqueous cooperative assembly route in the presence of basic amino acids as either polymerization catalysts or nitrogen dopants. This method allows the large-scale production of nitrogen-doped OMCs with tunable composition, structure and morphology while maintaining highly ordered mesostructures. For instances, the nitrogen content can be varied from ∼1 wt% to ∼6.3 wt% and the mesophase can be either 3-D body-centered cubic or 2-D hexagonal. The specific surface area for typical OMCs is around 600 m2 g-1, and further KOH activation can significantly enhance the surface area to 1866 m2 g-1 without destroying the ordered mesostructures. Benefiting from hierarchically ordered porous structure, nitrogen-doping effect and large-scale production availability, the synthesized OMCs show a great potential towards supercapacitor application. When measured in a symmetrical two-electrode configuration with an areal mass loading of ∼3 mg cm-2, the activated OMC exhibits high capacitance (186 F g-1 at 0.25 A g-1) and good rate capability (75% capacity retention at 20 A g-1) in ionic liquid electrolyte. Even as the mass loading is up to ∼12 mg cm-2, the OMC electrode still yields a specific capacitance of 126 F g-1 at 20 A g-1.

  15. Ordered mesoporous silica materials with complicated structures

    KAUST Repository

    Han, Yu

    2012-05-01

    Periodically ordered mesoporous silicas constitute one of the most important branches of porous materials that are extensively employed in various chemical engineering applications including adsorption, separation and catalysis. This short review gives an introduction to recently developed mesoporous silicas with emphasis on their complicated structures and synthesis mechanisms. In addition, two powerful techniques for solving complex mesoporous structures, electron crystallography and electron tomography, are compared to elucidate their respective strength and limitations. Some critical issues and challenges regarding the development of novel mesoporous structures as well as their applications are also discussed. © 2011 Elsevier Ltd.

  16. Phenol-formaldehyde carbon with ordered/disordered bimodal mesoporous structure as high-performance electrode materials for supercapacitors

    Science.gov (United States)

    Cai, Tingwei; Zhou, Min; Han, Guangshuai; Guan, Shiyou

    2013-11-01

    A novel phenol-formaldehyde carbon with ordered/disordered bimodal mesoporous structure is synthesized by the facile evaporation induced self-assembly strategy under a basic aqueous condition with SiO2 particles as template. The prepared bimodal mesoporous carbons (BMCs) are composed of ordered mesoporous and disordered mesoporous with diameter of about 3.5 nm and 7.0 nm, respectively. They can be employed as supercapacitor electrodes in H2SO4 aqueous electrolyte after the simple acid-treatment. BMC exhibits an exceptional specific capacitance of 344 F g-1 at the current density of 0.1 A g-1, although it has a relatively low surface area of 722 m2 g-1. And the BMC electrode displays an excellent cycling stability over 10,000 cycles.

  17. Highly-ordered mesoporous titania thin films prepared via surfactant assembly on conductive indium-tin-oxide/glass substrate and its optical properties

    International Nuclear Information System (INIS)

    Uchida, Hiroshi; Patel, Mehul N.; May, R. Alan; Gupta, Gaurav; Stevenson, Keith J.; Johnston, Keith P.

    2010-01-01

    Highly ordered mesoporous titanium dioxide (titania, TiO 2 ) thin films on indium-tin-oxide (ITO) coated glass were prepared via a Pluronic (P123) block copolymer template and a hydrophilic TiO 2 buffer layer. The contraction of the 3D hexagonal array of P123 micelles upon calcination merges the titania domains on the TiO 2 buffer layer to form mesoporous films with a mesochannel diameter of approximately 10 nm and a pore-to-pore distance of 10 nm. The mesoporous titania films on TiO 2 -buffered ITO/glass featured an inverse mesospace with a hexagonally-ordered structure, whereas the films formed without a TiO 2 buffer layer had a disordered microstructure with submicron cracks because of non-uniform water condensation on the hydrophobic ITO/glass surface. The density of the mesoporous film was 83% that of a bulk TiO 2 film. The optical band gap of the mesoporous titania thin film was approximately 3.4 eV, larger than that for nonporous anatase TiO 2 (∼ 3.2 eV), suggesting that the nanoscopic grain size leads to an increase in the band gap due to weak quantum confinement effects. The ability to form highly-ordered mesoporous titania films on electrically conductive and transparent substrates offers the potential for facile fabrication of high surface area semiconductive films with small diffusion lengths for optoelectronics applications.

  18. Ordered mesoporous silica materials with complicated structures

    KAUST Repository

    Han, Yu; Zhang, Daliang

    2012-01-01

    Periodically ordered mesoporous silicas constitute one of the most important branches of porous materials that are extensively employed in various chemical engineering applications including adsorption, separation and catalysis. This short review

  19. Triconstituent co-assembly to ordered mesostructured polymer-silica and carbon-silica nanocomposites and large-pore mesoporous carbons with high surface areas.

    Science.gov (United States)

    Liu, Ruili; Shi, Yifeng; Wan, Ying; Meng, Yan; Zhang, Fuqiang; Gu, Dong; Chen, Zhenxia; Tu, Bo; Zhao, Dongyuan

    2006-09-06

    Highly ordered mesoporous polymer-silica and carbon-silica nanocomposites with interpenetrating networks have been successfully synthesized by the evaporation-induced triconstituent co-assembly method, wherein soluble resol polymer is used as an organic precursor, prehydrolyzed TEOS is used as an inorganic precursor, and triblock copolymer F127 is used as a template. It is proposed for the first time that ordered mesoporous nanocomposites have "reinforced concrete"-structured frameworks. By adjusting the initial mass ratios of TEOS to resol, we determined the obtained nanocomposites possess continuous composition with the ratios ranging from zero to infinity for the two constituents that are "homogeneously" dispersed inside the pore walls. The presence of silicates in nanocomposites dramatically inhibits framework shrinkage during the calcination, resulting in highly ordered large-pore mesoporous carbon-silica nanocomposites. Combustion in air or etching in HF solution can remove carbon or silica from the carbon-silica nanocomposites and yield ordered mesoporous pure silica or carbon frameworks. The process generates plenty of small pores in carbon or/and silica pore walls. Ordered mesoporous carbons can then be obtained with large pore sizes of approximately 6.7 nm, pore volumes of approximately 2.0 cm(3)/g, and high surface areas of approximately 2470 m(2)/g. The pore structures and textures can be controlled by varying the sizes and polymerization degrees of two constituent precursors. Accordingly, by simply tuning the aging time of TEOS, ordered mesoporous carbons with evident bimodal pores at 2.6 and 5.8 nm can be synthesized.

  20. Highly stable and active Ni-doped ordered mesoporous carbon catalyst on the steam reforming of ethanol application

    Directory of Open Access Journals (Sweden)

    Josh Y.Z. Chiou

    2017-02-01

    Full Text Available A novel one-step direct synthesis of nickel embedded in an ordered mesoporous carbon catalyst (NiOMC is done in a basic medium of nonaqueous solution by a solvent evaporation-induced self-assembly process. The NiOMC sample is characterized by a variety of analytical and spectroscopy techniques, e.g., N2 adsorption/desorption isotherm measurement, X-ray diffraction (XRD, transmission electron microscopy (TEM and temperature-programed reduction (TPR. In this study, the NiOMC catalyst is found to exhibit superior catalytic activity for the steam reforming of ethanol (SRE, showing high hydrogen selectivity and durability. Ethanol can be completely converted at 350 °C over the NiOMC catalyst. Also, the durability of the NiOMC catalyst on the SRE reaction exceeds 100 h at 450 °C, with SH2 approaching 65% and SCO of less than 1%.

  1. Synthesis of three-dimensionally ordered macro-/mesoporous Pt with high electrocatalytic activity by a dual-templating approach

    Science.gov (United States)

    Zhang, Chengwei; Yang, Hui; Sun, Tingting; Shan, Nannan; Chen, Jianfeng; Xu, Lianbin; Yan, Yushan

    2014-01-01

    Three dimensionally ordered macro-/mesoporous (3DOM/m) Pt catalysts are fabricated by chemical reduction employing a dual-templating synthesis approach combining both colloidal crystal (opal) templating (hard-templating) and lyotropic liquid crystal templating (soft-templating) techniques. The macropore walls of the prepared 3DOM/m Pt exhibit a uniform mesoporous structure composed of polycrystalline Pt nanoparticles. Both the size of the mesopores and Pt nanocrystallites are in the range of 3-5 nm. The 3DOM/m Pt catalyst shows a larger electrochemically active surface area (ECSA), and higher catalytic activity as well as better poisoning tolerance for methanol oxidation reaction (MOR) than the commercial Pt black catalyst.

  2. Free-standing, well-aligned ordered mesoporous carbon nanofibers on current collectors for high-power micro-supercapacitors.

    Science.gov (United States)

    Kang, Eunae; Jeon, Gumhye; Kim, Jin Kon

    2013-07-21

    The mesoporous carbon nanofiber arrays that stand on carbon-gold double-layer current collectors are synthesized by self-assembly of a PS-b-PEO copolymer and resol in AAO templates for a high-power micro-supercapacitor at high current densities.

  3. Ordered mesoporous silica (OMS) as an adsorbent and membrane for separation of carbon dioxide (CO2).

    Science.gov (United States)

    Chew, Thiam-Leng; Ahmad, Abdul L; Bhatia, Subhash

    2010-01-15

    Separation of carbon dioxide (CO(2)) from gaseous mixture is an important issue for the removal of CO(2) in natural gas processing and power plants. The ordered mesoporous silicas (OMS) with uniform pore structure and high density of silanol groups, have attracted the interest of researchers for separation of carbon dioxide (CO(2)) using adsorption process. These mesoporous silicas after functionalization with amino groups have been studied for the removal of CO(2). The potential of functionalized ordered mesoporous silica membrane for separation of CO(2) is also recognized. The present paper reviews the synthesis of mesoporous silicas and important issues related to the development of mesoporous silicas. Recent studies on the CO(2) separation using ordered mesoporous silicas (OMS) as adsorbent and membrane are highlighted. The future prospectives of mesoporous silica membrane for CO(2) adsorption and separation are also presented and discussed. Copyright 2009 Elsevier B.V. All rights reserved.

  4. Enhanced photocatalytic properties in well-ordered mesoporous WO3

    KAUST Repository

    Li, Li; Krissanasaeranee, Methira; Pattinson, Sebastian W.; Stefik, Morgan; Wiesner, Ulrich; Steiner, Ullrich; Eder, Dominik

    2010-01-01

    We used polyisoprene-block-ethyleneoxide copolymers as structure-directing agents to synthesise well-ordered and highly-crystalline mesoporous WO 3 architectures that possess improved photocatalytic properties due to enhanced dye-adsorption in absence of diffusion limitation. © 2010 The Royal Society of Chemistry.

  5. Ordered Mesoporous Titania/Carbon Hybrid Monoliths for Lithium-ion Battery Anodes with High Areal and Volumetric Capacity.

    Science.gov (United States)

    Dörr, Tobias S; Fleischmann, Simon; Zeiger, Marco; Grobelsek, Ingrid; de Oliveira, Peter W; Presser, Volker

    2018-04-25

    Free-standing, binder-free, and conductive additive-free mesoporous titanium dioxide/carbon hybrid electrodes were prepared from co-assembly of a poly(isoprene)-block-poly(styrene)-block-poly(ethylene oxide) block copolymer and a titanium alkoxide. By tailoring an optimized morphology, we prepared macroscopic mechanically stable 300 μm thick monoliths that were directly employed as lithium-ion battery electrodes. High areal mass loading of up to 26.4 mg cm -2 and a high bulk density of 0.88 g cm -3 were obtained. This resulted in a highly increased volumetric capacity of 155 mAh cm -3 , compared to cast thin film electrodes. Further, the areal capacity of 4.5 mAh cm -2 represented a 9-fold increase compared to conventionally cast electrodes. These attractive performance metrics are related to the superior electrolyte transport and shortened diffusion lengths provided by the interconnected mesoporous nature of the monolith material, assuring superior rate handling, even at high cycling rates. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Ordered mesoporous silica-based inorganic nanocomposites

    International Nuclear Information System (INIS)

    Wang Qingqing; Shantz, Daniel F.

    2008-01-01

    This article reviews the synthesis and characterization of nanoparticles and nanowires grown in ordered mesoporous silicas (OMS). Summarizing work performed over the last 4 years, this article highlights the material properties of the final nanocomposite in the context of the synthesis methodology employed. While certain metal-OMS systems (e.g. gold in MCM-41) have been extensively studied this article highlights that there is a rich set of chemistries that have yet to be explored. The article concludes with some thoughts on future developments and challenges in this area. - Graphical abstract: HAADF TEM image of gold nanoparticles in amine-functionalized MCM-41 (from Ref. [22])

  7. Ordered hierarchical mesoporous/microporous carbon derived from mesoporous titanium-carbide/carbon composites and its electrochemical performance in supercapacitor

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Hai-Jing; Wang, Jie; Wang, Cong-Xiao; Xia, Yong-Yao [Department of Chemistry and Shanghai Key Laboratory of Molecular, Catalysis and Innovative Materials, Institute of New Energy, Fudan University, Shanghai (China)

    2011-11-15

    Novel ordered hierarchical mesoporous/microporous carbon (OHMMC) derived from mesoporous titanium-carbide/carbon composites was prepared for the first time by synthesizing ordered mesoporous nanocrystalline titanium-carbide/carbon composites, followed by chlorination of titanium carbides. The mesostructure and microstructure can be conveniently tuned by controlling the TiC contents of mesoporous TiC/C composite precursor, and chlorination temperature. By optimal condition, the OHMMC has a high surface area (1917 m{sup 2}g{sup -1}), large pore volumes (1.24 cm{sup 3}g{sup -1}), narrow mesopore-size distributions (centered at about 3 nm), and micropore size of 0.69 and 1.25 nm, and shows a great potential as electrode for supercapacitor applications: it exhibits a high capacitance of 146 Fg{sup -1} in noaqueous electrolyte and excellent rate capability. The ordered mesoporous channel pores are favorable for retention and immersion of the electrolyte, providing a more favorable path for electrolyte penetration and transportation to achieve promising rate capability performance. Meanwhile, the micropores drilled on the mesopore-walls can increase the specific surface area to provide more sites for charge storage. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  8. Ordered mesoporous carbon for electrochemical sensing: A review

    Energy Technology Data Exchange (ETDEWEB)

    Ndamanisha, Jean Chrysostome [Faculty of Chemistry, Northeast Normal University, Changchun 130024 (China); Universite du Burundi, Institut de pedagogie appliquee, B.P. 5223, Bujumbura (Burundi); Guo Liping, E-mail: guolp078@nenu.edu.cn [Faculty of Chemistry, Northeast Normal University, Changchun 130024 (China)

    2012-10-17

    Highlights: Black-Right-Pointing-Pointer The preparation and functionalization of ordered mesoporous carbon. Black-Right-Pointing-Pointer Their applications as electrochemical sensors with high electrocatalytic activity. Black-Right-Pointing-Pointer A promising electrode material based on its interesting properties. - Abstract: With its well-ordered pore structure, high specific surface area and tunable pore diameters in the mesopore range, ordered mesoporous carbon (OMC) is suitable for applications in catalysis and sensing. We report recent applications of OMC in electrochemical sensors and biosensors. After a brief description of the electrochemical properties, the functionalization of the OMC for improvement of the electrocatalytic properties is then presented. We show how the ordered mesostructure of OMC is very important in those applications. The high density of edge plane-like defective sites (EDSs), oxygen-containing groups and a large surface area on OMC may provide many favorable sites for electron transfer to compounds, which makes OMC a potential novel material for an investigation of the electrochemical behavior of substances. Moreover, the structural capabilities of OMC at the scale of a few nanometers agree with immobilization of other electrocataytic substances. Interesting properties of this material may open up a new approach to study the electrochemical determination of other biomolecules.

  9. High electrochemical performance of RuO_2–Fe_2O_3 nanoparticles embedded ordered mesoporous carbon as a supercapacitor electrode material

    International Nuclear Information System (INIS)

    Xiang, Dong; Yin, Longwei; Wang, Chenxiang; Zhang, Luyuan

    2016-01-01

    The electrode materials RuO_2 or RuO_2–Fe_2O_3 nanoparticle embedded OMC (ordered mesoporous carbon) are prepared by the method of impregnation and heating in situ. The mesoporous structure optimized the electron and proton conducting pathways, leading to the enhanced capacitive performances of the composite materials. The average nanoparticle size of RuO_2 and RuO_2–Fe_2O_3 is 2.54 and 1.96 nm, respectively. The fine RuO_2–Fe_2O_3 nanoparticles are dispersed evenly in the pore channel wall of the two-dimensional mesoporous carbon without blocking the mesoporous channel, and they have a higher specific surface area, a larger pore volume, a proper pore size and a small charge transfer impedance value. The special electrochemical capacitance of RuO_2–Fe_2O_3/OMC tested in acid electrolyte (H_2SO_4) is measured to be as high as 1668 F g"−"1, which is higher than that of RuO_2/OMC. Meanwhile, the supercapacitor properties of the RuO_2–Fe_2O_3/OMC composites show a good cycling performance of 93% capacitance retention (3000 cycles), a better reversibility, a higher energy density (134 Wh kg"−"1) and power density (4000 W kg"−"1). The composite electrode of RuO_2–Fe_2O_3/OMC, which combines a double layer capacitance with pseudo-capacitance, is proved to be suitable for ideal high performance electrode material of a hybrid supercapacitor application. - Highlights: • The nanocomposites of RuO_2–Fe_2O_3/OMC are prepared by impregnation and heating in situ. • The fine RuO_2–Fe_2O_3 nanoparticles distribute in the pore channel wall of OMC. • We discuss a reversible redox reaction mechanism of RuO_2–Fe_2O_3/OMC in acid solutions. • RuO_2–Fe_2O_3 nanoparticles embedded OMC shows a higher supercapacitive performance.

  10. Nitrogen-doped ordered mesoporous carbon with a high surface area, synthesized through organic-inorganic coassembly, and its application in supercapacitors.

    Science.gov (United States)

    Song, Yanfang; Li, Li; Wang, Yonggang; Wang, Congxiao; Guo, Zaipin; Xia, Yongyao

    2014-07-21

    A new nitrogen-doped ordered mesoporous carbon (N-doped OMC) is synthesized by using an organic-inorganic coassembly method, in which resol is used as the carbon precursor, dicyandiamide as the nitrogen precursor, silicate oligomers as the inorganic precursors, and F127 as the soft template. The N-doped OMC possesses a surface area as high as 1374 m(2)  g(-1) and a large pore size of 7.4 nm. As an electrode material for supercapacitors, the obtained carbon exhibits excellent cycling stability and delivers a reversible specific capacitance as high as 308 F g(-1) in 1 mol L(-1) H(2)SO(4) aqueous electrolyte, of which 58 % of the capacity is due to pseudo-capacitance. The large specific capacitance is attributed to proper pore size distributions, large surface area, and high nitrogen content. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. CTAB assisted microwave synthesis of ordered mesoporous carbon supported Pt nanoparticles for hydrogen electro-oxidation

    International Nuclear Information System (INIS)

    Zhou, Jian-Hua; He, Jian-Ping; Ji, Ya-Jun; Dang, Wang-Juan; Liu, Xiao-Lei; Zhao, Gui-Wang; Zhang, Chuan-Xiang; Zhao, Ji-Shuang; Fu, Qing-Bin; Hu, Huo-Ping

    2007-01-01

    Mesoporous carbon with ordered hexagonal structure derived from the co-assembly of triblock copolymer F127 and resol was employed as the carbon support of Pt catalysts for hydrogen electro-oxidation. Structural characterizations revealed that the mesoporous carbon exhibited large surface area and uniform mesopores. The Pt nanoparticles supported on the novel mesoporous carbon were fabricated by a facile CTAB assisted microwave synthesis process, wherein CTAB was expected to improve the wettability of carbon support as well as the dispersion of Pt nanoparticles. X-ray diffraction and transmission electron microscopy were applied to characterize the Pt catalysts. It was found that the Pt nanoparticles were uniform in size and highly dispersed on the mesoporous carbon supports. The cyclic voltammograms in sulfuric acid demonstrated that the electrochemical active surface area of Pt catalysts prepared with CTAB was two times than that without CTAB

  12. Electrochemical detection of ultratrace nitroaromatic explosives using ordered mesoporous carbon

    Energy Technology Data Exchange (ETDEWEB)

    Zang Jianfeng; Guo Chunxian; Hu Fengping [School of Chemical and Biomedical Engineering and Center for Advanced Bionanosystems, Nanyang Technological University, 70 Nanyang Drive, Singapore 637457 (Singapore); Yu Lei [Department of Chemical, Materials and Biomolecular Engineering, University of Connecticut, Storrs, CT 06269 (United States); Li Changming, E-mail: ecmli@ntu.edu.sg [School of Chemical and Biomedical Engineering and Center for Advanced Bionanosystems, Nanyang Technological University, 70 Nanyang Drive, Singapore 637457 (Singapore)

    2011-01-10

    A sensitive electrochemical sensor has been fabricated to detect ultratrace nitroaromatic explosives using ordered mesoporus carbon (OMC). OMC was synthesized and characterized by scanning electron microscopy, transmission electron microscopy and nitrogen adsorption/desorption measurements. Glassy carbon electrodes functionalized with OMC show high sensitivity of 62.7 {mu}A cm{sup -2} per ppb towards 2,4,6-trinitrotoluene (TNT). By comparison with other materials such as carbon nanotubes and ordered mesoporous silica, it is found that the high performance of OMC toward sensing TNT is attributed to its large specific surface area and fast electron transfer capability. As low as 0.2 ppb TNT, 1 ppb 2,4-dinitrotoluene and 1 ppb 1,3-dinitrobenzene can be detected on OMC based electrodes. This work renders new opportunities to detect ultratrace explosives for applications of environment protections and home securities against chemical warfare agents.

  13. Hierarchically ordered macro-mesoporous ZnS microsphere with reduced graphene oxide supporter for a highly efficient photodegradation of methylene blue

    Energy Technology Data Exchange (ETDEWEB)

    Sookhakian, M., E-mail: m.sokhakian@gmail.com [Department of Physics, University of Malaya, Kuala Lumpur 50603 (Malaysia); Amin, Y.M. [Department of Physics, University of Malaya, Kuala Lumpur 50603 (Malaysia); Basirun, W.J. [Department of Chemistry, University of Malaya, Kuala Lumpur 50603 (Malaysia); Centre of Research in Nanotechnology and Catalysis (NanoCat), Institute of Postgraduate Studies, University Malaya, Kuala Lumpur 50603 (Malaysia)

    2013-10-15

    A facile one-pot method for the fabrication of high quality self-assembled hierarchically ordered macro-mesoporous ZnS microsphere–reduced graphene oxide (RGO) composite without the use of templates or surfactants is described. During the hydrothermal process, reduced graphene oxide (RGO) was loaded into the ZnS microsphere by in situ reduction of graphene oxide added in the self-assembly system. The morphology and structure of the as-prepared composites were confirmed by X-ray diffraction, high resolution transmission electron microscopy, energy dispersive X-ray analysis, Fourier transform infrared spectroscopy and Raman spectroscopy. Incorporation of reduced graphene oxide as an excellent electron-transporting material effectively suppresses the charge recombination. Hence, a significant enhancement in the photocatalytic efficiency for the photodegradation of methylene blue was observed with the ZnS–RGO composite, compared to the pure ZnS. Overall, this research results may lay down new vistas for the in situ fabrication of the ZnS–RGO composite as a highly efficient photocatalysis under visible-light irradiation and their applications in environmental protection.

  14. Synthesis of ordered mesoporous uranium dioxide by a nanocasting route

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Ran; Wang Lin; Shi, Wei-Qun [Chinese Academy of Sciences, Beijing (China). Laboratory of Nuclear Energy Chemistry and Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety; Chai, Zhi-Fang [Chinese Academy of Sciences, Beijing (China). Laboratory of Nuclear Energy Chemistry and Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety; Soochow Univ., Suzhou (China). School of Radiological and Interdisciplinary Sciences and Collaborative Innovation Center

    2016-11-01

    Ordered mesoporous UO{sub 2} with 3-D structure (for UO{sub 2}-KIT-6) and nanowire bundles (for UO{sub 2}-SBA-15) was synthesized for the first time by a nanocasting route using different ordered mesoporous silica (KIT-6 and SBA-15, respectively) as templates and uranyl nitrate hexahydrate as the metal precursor. The uranyl nitrate was impregnated into the mesopore of the silica template and was converted to U{sub 3}O{sub 8} after the first step. The synthesis of ordered UO{sub 2} mesostructure was achieved by reducing the mesoporous U{sub 3}O{sub 8} with silica composites under 5% H{sub 2}/Ar atmosphere at 700 C, followed by a template removal process. The as-prepared UO{sub 2}-KIT-6 had a particle size of several millimeters, and was constructed with uncoupled subframework mesostructure and crystalline walls, while UO{sub 2}-SBA-15 possessed a rope-like morphology and consisted of nanowire arrays. The surface area and pore volume of ordered UO{sub 2} mesostructure are 47.2 m{sup 2} g{sup -1} and 0.23 cm{sup 3} g{sup -1} for the UO{sub 2}-KIT-6, and 54.4 m{sup 2} g{sup -1} and 0.28 cm{sup 3} g{sup -1} for the UO{sub 2}-SBA-15, respectively.

  15. Preparation of a Si/SiO2 -Ordered-Mesoporous-Carbon Nanocomposite as an Anode for High-Performance Lithium-Ion and Sodium-Ion Batteries.

    Science.gov (United States)

    Zeng, Lingxing; Liu, Renpin; Han, Lei; Luo, Fenqiang; Chen, Xi; Wang, Jianbiao; Qian, Qingrong; Chen, Qinghua; Wei, Mingdeng

    2018-04-03

    In this work, an Si/SiO 2 -ordered-mesoporous carbon (Si/SiO 2 -OMC) nanocomposite was initially fabricated through a magnesiothermic reduction strategy by using a two-dimensional bicontinuous mesochannel of SiO 2 -OMC as a precursor, combined with an NaOH etching process, in which crystal Si/amorphous SiO 2 nanoparticles were encapsulated into the OMC matrix. Not only can such unique porous crystal Si/amorphous SiO 2 nanoparticles uniformly dispersed in the OMC matrix mitigate the volume change of active materials during the cycling process, but they can also improve electrical conductivity of Si/SiO 2 and facilitate the Li + /Na + diffusion. When applied as an anode for lithium-ion batteries (LIBs), the Si/SiO 2 -OMC composite displayed superior reversible capacity (958 mA h g -1 at 0.2 A g -1 after 100 cycles) and good cycling life (retaining a capacity of 459 mA h g -1 at 2 A g -1 after 1000 cycles). For sodium-ion batteries (SIBs), the composite maintained a high capacity of 423 mA h g -1 after 100 cycles at 0.05 A g -1 and an extremely stable reversible capacity of 190 mA h g -1 was retained even after 500 cycles at 1 A g -1 . This performance is one of the best long-term cycling properties of Si-based SIB anode materials. The Si/SiO 2 -OMC composites exhibited great potential as an alternative material for both lithium- and sodium-ion battery anodes. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Research on the Ordered Mesoporous Silica for Tobacco Harm Reduction

    Science.gov (United States)

    Wang, Y.; Y Li, Z.; Ding, J. X.; Hu, Z. J.; Liu, Z.; Zhou, G.; Huang, T. H.

    2017-12-01

    For reducting tobacco harm, this paper prepared an ordered mesoporous silica by using triblock copolymer Pluronic P123 as template. The property of this material was characterized by the X-ray scattering spectrum(XRD), Transmission electron microscopy(TEM), Scanning electron microscopy (SEM) and Nitrogen adsorption/desorption. Then this ordered mesoporous silica was added into the cigarette filter in order to researching its effect of cigarette harm index. The result shows that the feature of SBA-15 was grain morphology, ordered arrangement, tubular porous 2-D hexagonal structure. The application of SBA-15 in cigarette filter can selectively reduce harmful components in cigarette smoke such as crotonaldehyde, hydrogen cyanide, benzo pyrene and tar. The synthesized SBA-15 could properly reduce cigarette harm index.

  17. Ordered Mesoporous Carbons as Novel and Efficient Adsorbent for Dye Removal from Aqueous Solution

    OpenAIRE

    Phuong T. Dang; Hoa T. H. Nguyen; Canh D. Dao; Giang H. Le; Quang K. Nguyen; Kien T. Nguyen; Hoa T. K. Tran; Tuyen V. Nguyen; Tuan A. Vu

    2016-01-01

    Ordered mesoporous carbons (OMCs) were successfully synthesized by using hard template and soft template methods. These materials were characterized by XRD, TEM, and N2 adsorption-desorption Brunauer-Emmett-Teller (BET). From the obtained results, it is revealed that the obtained OMCs samples showed high surface area (>1000 m2/g) with high pore volume, mainly mesopore volume (1.2–2.4 cm3/g). Moreover, OMCs samples had similar structure of the SBA-15 silica and exhibited high MB adsorption cap...

  18. Spatially and size selective synthesis of Fe-based nanoparticles on ordered mesoporous supports as highly active and stable catalysts for ammonia decomposition.

    Science.gov (United States)

    Lu, An-Hui; Nitz, Joerg-Joachim; Comotti, Massimiliano; Weidenthaler, Claudia; Schlichte, Klaus; Lehmann, Christian W; Terasaki, Osamu; Schüth, Ferdi

    2010-10-13

    Uniform and highly dispersed γ-Fe(2)O(3) nanoparticles with a diameter of ∼6 nm supported on CMK-5 carbons and C/SBA-15 composites were prepared via simple impregnation and thermal treatment. The nanostructures of these materials were characterized by XRD, Mössbauer spectroscopy, XPS, SEM, TEM, and nitrogen sorption. Due to the confinement effect of the mesoporous ordered matrices, γ-Fe(2)O(3) nanoparticles were fully immobilized within the channels of the supports. Even at high Fe-loadings (up to about 12 wt %) on CMK-5 carbon no iron species were detected on the external surface of the carbon support by XPS analysis and electron microscopy. Fe(2)O(3)/CMK-5 showed the highest ammonia decomposition activity of all previously described Fe-based catalysts in this reaction. Complete ammonia decomposition was achieved at 700 °C and space velocities as high as 60,000 cm(3) g(cat)(-1) h(-1). At a space velocity of 7500 cm(3) g(cat)(-1) h(-1), complete ammonia conversion was maintained at 600 °C for 20 h. After the reaction, the immobilized γ-Fe(2)O(3) nanoparticles were found to be converted to much smaller nanoparticles (γ-Fe(2)O(3) and a small fraction of nitride), which were still embedded within the carbon matrix. The Fe(2)O(3)/CMK-5 catalyst is much more active than the benchmark NiO/Al(2)O(3) catalyst at high space velocity, due to its highly developed mesoporosity. γ-Fe(2)O(3) nanoparticles supported on carbon-silica composites are structurally much more stable over extended periods of time but less active than those supported on carbon. TEM observation reveals that iron-based nanoparticles penetrate through the carbon layer and then are anchored on the silica walls, thus preventing them from moving and sintering. In this way, the stability of the carbon-silica catalyst is improved. Comparison with the silica supported iron oxide catalyst reveals that the presence of a thin layer of carbon is essential for increased catalytic activity.

  19. Low-cost fabrication of highly sensitive room temperature hydrogen sensor based on ordered mesoporous Co-doped TiO2 structure

    Science.gov (United States)

    Li, Zhong; Haidry, Azhar Ali; Wang, Tao; Yao, Zheng Jun

    2017-07-01

    The development of cost-effective gas sensors with improved sensing properties and minimum power consumption for room temperature hydrogen leakage monitoring is in increasing demand. In this context, this report focus on the facile fabrication of ordered mesoporous TiO2 via evaporation-induced self-assembly route. With the controlled doping threshold (3%Co-TiO2), the output resistance change to 1000 ppm H2 is ˜4.1 × 103 with the response time of 66 s. The sensor response exhibits power law dependence with an increase in the hydrogen concentration, where the power law coefficient was found not only specific to the kind of target gas but also related to temperature. Further, the effect of structure integrity with doping level and humidity on sensing characteristics is interpreted in terms of variation in surface potential eVS and depletion region w caused by the adsorption of molecular oxygen O2-.

  20. Recent progress of ordered mesoporous silica-supported chiral metallic catalysts

    Directory of Open Access Journals (Sweden)

    LIU Rui

    2013-02-01

    Full Text Available Recently,ordered silica-based mesoporous chiral organometallics-functionalized heterogeneous catalysts have attracted extensive research interest due to their excellent properties,such as easy preparation,high activity and convenient recycle.This review mainly summarizesthe generally prepared strategy and the silica-based organometallics-functionalized heterogeneous catalysts reported in the literatures.

  1. Controlled Synthesis of Pt Nanowires with Ordered Large Mesopores for Methanol Oxidation Reaction

    Science.gov (United States)

    Zhang, Chengwei; Xu, Lianbin; Yan, Yushan; Chen, Jianfeng

    2016-08-01

    Catalysts for methanol oxidation reaction (MOR) are at the heart of key green-energy fuel cell technology. Nanostructured Pt materials are the most popular and effective catalysts for MOR. Controlling the morphology and structure of Pt nanomaterials can provide opportunities to greatly increase their activity and stability. Ordered nanoporous Pt nanowires with controlled large mesopores (15, 30 and 45 nm) are facilely fabricated by chemical reduction deposition from dual templates using porous anodic aluminum oxide (AAO) membranes with silica nanospheres self-assembled in the channels. The prepared mesoporous Pt nanowires are highly active and stable electrocatalysts for MOR. The mesoporous Pt nanowires with 15 nm mesopores exhibit a large electrochemically active surface area (ECSA, 40.5 m2 g-1), a high mass activity (398 mA mg-1) and specific activity (0.98 mA cm-2), and a good If/Ib ratio (1.15), better than the other mesoporous Pt nanowires and the commercial Pt black catalyst.

  2. Magnetic ordered mesoporous Fe3O4/CeO2 composites with synergy of adsorption and Fenton catalysis

    Science.gov (United States)

    Li, Keyan; Zhao, Yongqin; Song, Chunshan; Guo, Xinwen

    2017-12-01

    Magnetic Fe3O4/CeO2 composites with highly ordered mesoporous structure and large surface area were synthesized by impregnation-calcination method, and the mesoporous CeO2 as support was synthesized via the hard template approach. The composition, morphology and physicochemical properties of the materials were characterized by XRD, SEM, TEM, XPS, Raman spectra and N2 adsorption/desorption analysis. The mesoporous Fe3O4/CeO2 composite played a dual-function role as both adsorbent and Fenton-like catalyst for removal of organic dye. The methylene blue (MB) removal efficiency of mesoporous Fe3O4/CeO2 was much higher than that of irregular porous Fe3O4/CeO2. The superior adsorption ability of mesoporous materials was attributed to the abundant oxygen vacancies on the surface of CeO2, high surface area and ordered mesoporous channels. The good oxidative degradation resulted from high Ce3+ content and the synergistic effect between Fe and Ce. The mesoporous Fe3O4/CeO2 composite presented low metal leaching (iron 0.22 mg L-1 and cerium 0.63 mg L-1), which could be ascribed to the strong metal-support interactions for dispersion and stabilization of Fe species. In addition, the composite can be easily separated from reaction solution with an external magnetic field due to its magnetic property, which is important to its practical applications.

  3. Ordered Mesoporous NiCeAl Containing Catalysts for Hydrogenolysis of Sorbitol to Glycols

    Science.gov (United States)

    Zhou, Zhiwei; Zhang, Jiaqi; Qin, Juan; Li, Dong; Wu, Wenliang

    2018-03-01

    Cellulose-derived sorbitol is emerging as a feasible and renewable feedstock for the production of value-added chemicals. Highly active and stable catalyst is essential for sorbitol hydrogenolysis. Ordered mesoporous M- xNi yCeAl catalysts with different loadings of nickel and cerium species were successfully synthesized via one-pot evaporation-induced self-assembly strategy (EISA) and their catalytic performance were tested in the hydrogenolysis of sorbitol. The physical chemical properties for the catalysts were characterized by XRD, N2 physisorption, H2-TPR, H2 impulse chemisorption, ICP and TEM techniques. The results showed that the ordered mesopores with uniform pore sizes can be obtained and the Ni nanoparticles around 6 nm in size were homogeneously dispersed in the mesopore channels. A little amount of cerium species introduced would be beneficial to their textural properties resulting in higher Ni dispersion, metal area and smaller size of Ni nanoparticles. The M-10Ni2CeAl catalyst with Ni and Ce loading of 10.9 and 6.3 wt % shows better catalytic performance than other catalysts, and the yield of 1,2-PG and EG can reach 56.9% at 493 K and 6 MPa pressure for 8 h after repeating reactions for 12 times without obvious deterioration of physical and chemical properties. Ordered mesoporous M-NiCeAl catalysts are active and stable in sorbitol hydrogenolysis.

  4. Synthesis, characterization, and catalytic application of ordered mesoporous carbon–niobium oxide composites

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Juan-Li; Gao, Shuang; Liu, Chun-Ling; Liu, Zhao-Tie; Dong, Wen-Sheng, E-mail: wsdong@snnu.edu.cn

    2014-11-15

    Graphical abstract: The ordered mesoporous carbon–niobium oxide composites have been synthesized by a multi-component co-assembly method associated with a carbonization process. - Highlights: • Ordered mesoporous carbon–niobium oxide composites were synthesized. • The content of Nb{sub 2}O{sub 5} in the composites could be tuned from 38 to 75%. • Niobium species were highly dispersed in amorphous carbon framework walls. • The composites exhibited good catalytic performance in the dehydration of fructose. - Abstract: Ordered mesoporous carbon–niobium oxide composites have been synthesized by a multi-component co-assembly method associated with a carbonization process using phenolic resol as carbon source, niobium chloride as precursor and amphiphilic triblock copolymer Pluronic F127 as template. The resulting materials were characterized using a combination of techniques including differential scanning calorimetry–thermogravimetric analysis, N{sub 2} physical adsorption, X-ray diffraction, transmission electron microscopy, and X-ray photoelectron spectroscopy. The results show that with increasing the content of Nb{sub 2}O{sub 5} from 38 to 75% the specific surface area decreases from 306.4 to 124.5 m{sup 2} g{sup −1}, while the ordered mesoporous structure is remained. Niobium species is well dispersed in the amorphous carbon framework. The mesoporous carbon–niobium oxide composites exhibit high catalytic activity in the dehydration of fructose to 5-hydroxymethylfurfural. A 100% conversion of fructose and a 76.5% selectivity of 5-hydroxymethylfurfural were obtained over the carbon–niobium oxide composite containing 75% Nb{sub 2}O{sub 5} under the investigated reaction conditions.

  5. Ordered mesoporous polymer-silica hybrid nanoparticles as vehicles for the intracellular controlled release of macromolecules.

    Science.gov (United States)

    Kim, Tae-Wan; Slowing, Igor I; Chung, Po-Wen; Lin, Victor Shang-Yi

    2011-01-25

    A two-dimensional hexagonal ordered mesoporous polymer-silica hybrid nanoparticle (PSN) material was synthesized by polymerization of acrylate monomers on the surface of SBA-15 mesoporous silica nanoparticles. The structure of the PSN material was analyzed using a series of different techniques, including transmission electron microscopy, powder X-ray diffraction, and N(2) sorption analysis. These structurally ordered mesoporous polymer-silica hybrid nanoparticles were used for the controlled release of membrane-impermeable macromolecules inside eukaryotic cells. The cellular uptake efficiency and biocompatibility of PSN with human cervical cancer cells (HeLa) were investigated. Our results show that the inhibitory concentration (IC(50)) of PSN is very high (>100 μg/mL per million cells), while the median effective concentration for the uptake (EC(50)) of PSN is low (EC(50) = 4.4 μg/mL), indicating that PSNs are fairly biocompatible and easily up-taken in vitro. A membrane-impermeable macromolecule, 40 kDa FITC-Dextran, was loaded into the mesopores of PSNs at low pH. We demonstrated that the PSN material could indeed serve as a transmembrane carrier for the controlled release of FITC-Dextran at the pH level inside live HeLa cells. We believe that further developments of this PSN material will lead to a new generation of nanodevices for intracellular controlled delivery applications.

  6. Direct fabrication of ordered mesoporous carbons with super-micropore/small mesopore using mixed triblock copolymers.

    Science.gov (United States)

    Li, Peng; Song, Yan; Tang, Zhihong; Yang, Guangzhi; Yang, Junhe

    2014-01-01

    Ordered mesoporous carbons (OMCs) have been prepared by the strategy of evaporation-induced organic-organic self-assembly method by employing a mixture of amphiphilic triblock copolymers poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide) (PEO-PPO-PEO) and reverse PPO-PEO-PPO as templates, with soluble in ethanol, low-molecular-weight phenolic resin as precursor, followed by carbonization. It has been found that the as prepared OMCs with porosity that combines super-micropore and small mesopore size distributed from 0.8 to 4 nm, which bridges the pore size from 2 to 3 nm and also for the diversification of the soft-templating synthesis of OMCs. Furthermore, the results showed that the OMCs obtained have mesophase transition from cylindrical p6 mm to centered rectangular c2 mm structure by simply tuning the ratio of PPO-PEO-PPO/PEO-PPO-PEO. Copyright © 2013 Elsevier Inc. All rights reserved.

  7. Ordered Mesoporous Carbons as Novel and Efficient Adsorbent for Dye Removal from Aqueous Solution

    Directory of Open Access Journals (Sweden)

    Phuong T. Dang

    2016-01-01

    Full Text Available Ordered mesoporous carbons (OMCs were successfully synthesized by using hard template and soft template methods. These materials were characterized by XRD, TEM, and N2 adsorption-desorption Brunauer-Emmett-Teller (BET. From the obtained results, it is revealed that the obtained OMCs samples showed high surface area (>1000 m2/g with high pore volume, mainly mesopore volume (1.2–2.4 cm3/g. Moreover, OMCs samples had similar structure of the SBA-15 silica and exhibited high MB adsorption capacity with qm of 398 mg·g−1 for OMCs synthesis with hard template and 476 mg·g−1 for OMCs synthesis with soft template, respectively. From kinetics investigation, it is confirmed that MB adsorption from aqueous solution obeys the pseudo-second-order kinetic equation.

  8. Ordered mesoporous carbon coating on cordierite: Synthesis and application as an efficient adsorbent

    Energy Technology Data Exchange (ETDEWEB)

    Wan, Ying, E-mail: ywan@shnu.edu.cn [Key Laboratory of Resource Chemistry of Ministry of Education, Shanghai Key Laboratory of Rare Earth Functional Materials, Shanghai Normal University, Shanghai 200234 (China); Department of Chemistry, Shanghai Normal University, Shanghai 200234 (China); Cui, Xiangting; Wen, Zhentao [Department of Chemistry, Shanghai Normal University, Shanghai 200234 (China)

    2011-12-30

    Highlight: Black-Right-Pointing-Pointer Surfactant self-assembly of ordered mesoporous carbon coating on honeycomb cordierite. Black-Right-Pointing-Pointer Carbon coating with opened, hexagonally ordered pore arrays. Black-Right-Pointing-Pointer Honeycomb adsorbents for removal of p-chlorophenol. Black-Right-Pointing-Pointer The adsorbents exhibit large processing volume, and great advantages in reusability. - Abstract: Ordered mesoporous carbon coating on the honeycomb cordierite substrate has been prepared using low-polymerized phenolic resins as carbon sources and triblock copolymer F127 as the structure directing agent via the evaporation induced self-assembly route. The high-resolution scanning electron microscopy (HRSEM), transmission electron microscopy (TEM), and nitrogen sorption techniques prove the hexagonally ordered pore arrays of carbon coating on the cordierite. The honeycomb monolith adsorbents coated by ordered mesoporous carbons are directly used without any activation, and exhibit adsorption capacities for chlorinated organic pollutants in water with 200 mg/g for p-chlorophenol and 178 mg/g for p-chloroaniline (with respect to the net carbon coating), high adsorption ratio for low-concentration pollutants, large processing volumes and reusability. More than 200 repeated times can be achieved without obvious loss in both adsorption capacity and weight.

  9. Dipolar rotors orderly aligned in mesoporous fluorinated organosilica architectures

    KAUST Repository

    Bracco, Silvia; Beretta, Mario; Cattaneo, Alice Silvia; Comotti, Angiolina; Falqui, Andrea; Zhao, Ke; Rogers, Charles T.; Sozzani, Piero

    2015-01-01

    New mesoporous covalent frameworks, based on hybrid fluorinated organosilicas, were prepared to realize a periodic architecture of fast molecular rotors containing dynamic dipoles in their structure. The mobile elements, designed on the basis of fluorinated p-divinylbenzene moieties, were integrated into the robust covalent structure through siloxane bonds, and showed not only the rapid dynamics of the aromatic rings (ca. 108 Hz at 325 K), as detected by solid-state NMR spectroscopy, but also a dielectric response typical of a fast dipole reorientation under the stimuli of an applied electric field. Furthermore, the mesochannels are open and accessible to diffusing in gas molecules, and rotor mobility could be individually regulated by I2 vapors. The iodine enters the channels of the periodic structure and reacts with the pivotal double bonds of the divinyl-fluoro-phenylene rotors, affecting their motion and the dielectric properties. Oriented molecular rotors: Fluorinated molecular rotors (see picture) were engineered in mesoporous hybrid organosilica architectures with crystalline order in their walls. The rotor dynamics was established by magic angle spinning NMR and dielectric measurements, indicating a rotational correlation time as short as 10-9 s at 325 K. The dynamics was modulated by I2 vapors entering the pores.

  10. Dipolar rotors orderly aligned in mesoporous fluorinated organosilica architectures

    KAUST Repository

    Bracco, Silvia

    2015-02-16

    New mesoporous covalent frameworks, based on hybrid fluorinated organosilicas, were prepared to realize a periodic architecture of fast molecular rotors containing dynamic dipoles in their structure. The mobile elements, designed on the basis of fluorinated p-divinylbenzene moieties, were integrated into the robust covalent structure through siloxane bonds, and showed not only the rapid dynamics of the aromatic rings (ca. 108 Hz at 325 K), as detected by solid-state NMR spectroscopy, but also a dielectric response typical of a fast dipole reorientation under the stimuli of an applied electric field. Furthermore, the mesochannels are open and accessible to diffusing in gas molecules, and rotor mobility could be individually regulated by I2 vapors. The iodine enters the channels of the periodic structure and reacts with the pivotal double bonds of the divinyl-fluoro-phenylene rotors, affecting their motion and the dielectric properties. Oriented molecular rotors: Fluorinated molecular rotors (see picture) were engineered in mesoporous hybrid organosilica architectures with crystalline order in their walls. The rotor dynamics was established by magic angle spinning NMR and dielectric measurements, indicating a rotational correlation time as short as 10-9 s at 325 K. The dynamics was modulated by I2 vapors entering the pores.

  11. Ordered mesoporous crystalline gamma-Al2O3 with variable architecture and porosity from a single hard template.

    Science.gov (United States)

    Wu, Zhangxiong; Li, Qiang; Feng, Dan; Webley, Paul A; Zhao, Dongyuan

    2010-09-01

    In this paper, an efficient route is developed for controllable synthesis of ordered mesoporous alumina (OMA) materials with variable pore architectures and high mesoporosity, as well as crystalline framework. The route is based on the nanocasting pathway with bimodal mesoporous carbon as the hard template. In contrast to conventional reports, we first realize the possibility of creating two ordered mesopore architectures by using a single carbon hard template obtained from organic-organic self-assembly, which is also the first time such carbon materials are adopted to replicate ordered mesoporous materials. The mesopore architecture and surface property of the carbon template are rationally designed in order to obtain ordered alumina mesostructures. We found that the key factors rely on the unique bimodal mesopore architecture and surface functionalization of the carbon hard template. Namely, the bimodal mesopores (2.3 and 5.9 nm) and the surface functionalities make it possible to selectively load alumina into the small mesopores dominantly and/or with a layer of alumina coated on the inner surface of the large primary mesopores with different thicknesses until full loading is achieved. Thus, OMA materials with variable pore architectures (similar and reverse mesostructures relative to the carbon template) and controllable mesoporosity in a wide range are achieved. Meanwhile, in situ ammonia hydrolysis for conversion of the metal precursor to its hydroxide is helpful for easy crystallization (as low as approximately 500 degrees C). Well-crystallized alumina frameworks composed of gamma-Al(2)O(3) nanocrystals with sizes of 6-7 nm are obtained after burning out the carbon template at 600 degrees C, which is advantageous over soft-templated aluminas. The effects of synthesis factors are demonstrated and discussed relative to control experiments. Furthermore, our method is versatile enough to be used for general synthesis of other important but difficult

  12. Ordered mesoporous polyaniline film as a new matrix for enzyme immobilization and biosensor construction

    International Nuclear Information System (INIS)

    Xu Qin; Zhu Junjie; Hu Xiaoya

    2007-01-01

    Ordered mesoporous polyaniline film has been fabricated by electrodepositing from the hexagonal lyotropic liquid crystalline (LCC). Horseradish peroxidase (HRP), as a symbol biomolecule, was successfully immobilized on the film to construct a new kind of hydrogen peroxide biosensor. The biosensor combined the advantages of the good conductivity of polyaniline and the higher surface area of the ordered mesoporous film. Polyaniline could be served as a wire to relay electron between HRP and the electrode. The high surface area of the film supplied more sites for HRP immobilization, therefore increased the catalytic activity of the biosensor. The ordered mesoporous character of the film increased the rate of mass transport, which resulted in the improvement of sensor response and linearity. The biosensor displayed excellent electrocatalytic response to the detection of H 2 O 2 in a concentration range from 1.0 μM to 2.0 mM with a detection limit of 0.63 μM. Good reproducibility, stability, high precision, wide linearity and low detection limit were assessed for the biosensor

  13. Iron-Induced Activation of Ordered Mesoporous Nickel Cobalt Oxide Electrocatalyst for the Oxygen Evolution Reaction.

    Science.gov (United States)

    Deng, Xiaohui; Öztürk, Secil; Weidenthaler, Claudia; Tüysüz, Harun

    2017-06-28

    Herein, ordered mesoporous nickel cobalt oxides prepared by the nanocasting route are reported as highly active oxygen evolution reaction (OER) catalysts. By using the ordered mesoporous structure as a model system and afterward elevating the optimal catalysts composition, it is shown that, with a simple electrochemical activation step, the performance of nickel cobalt oxide can be significantly enhanced. The electrochemical impedance spectroscopy results indicated that charge transfer resistance increases for Co 3 O 4 spinel after an activation process, while this value drops for NiO and especially for CoNi mixed oxide significantly, which confirms the improvement of oxygen evolution kinetics. The catalyst with the optimal composition (Co/Ni 4/1) reaches a current density of 10 mA/cm 2 with an overpotential of a mere 336 mV and a Tafel slope of 36 mV/dec, outperforming benchmarked and other reported Ni/Co-based OER electrocatalysts. The catalyst also demonstrates outstanding durability for 14 h and maintained the ordered mesoporous structure. The cyclic voltammograms along with the electrochemical measurements in Fe-free KOH electrolyte suggest that the activity boost is attributed to the generation of surface Ni(OH) 2 species that incorporate Fe impurities from the electrolyte. The incorporation of Fe into the structure is also confirmed by inductively coupled plasma optical emission spectrometry.

  14. Efficient capture of CO2 over ordered micro-mesoporous hybrid carbon nanosphere

    Science.gov (United States)

    Chen, Changwei; Yu, Yanke; He, Chi; Wang, Li; Huang, Huang; Albilali, Reem; Cheng, Jie; Hao, Zhengping

    2018-05-01

    Four kinds of carbon-based adsorbents (micro-mesoporous hybrid carbon nanosphere and N-doped hollow carbon sphere with single-, double- or ruga-shell morphology) with different structural and textural properties were prepared and systematically studied in CO2 capture. All synthesized samples possess high specific surface area (828-910 m2 g-1), large pore volume (0.71-1.81 cm3 g-1), and different micropore contents varied from 2.1% to 46.4%. Amongst, the ordered micro-mesoporous carbon nanosphere (OM-CNS) exhibits the best adsorption performance with CO2 uptake as high as 3.01 mmol g-1 under conditions of 298 K and 1.0 bar, better than most of the reported CO2 adsorbents. The excellent CO2 adsorption capacity of OM-CNS can be reasonably attributed to the synergistic effect of ordered mesopore channels and abundant structural micropores which are beneficial for the diffusion and trapping of CO2 adsorbate. Moreover, the OM-CNS shows excellent CO2 trapping selectivity and superior stability and recyclability, which endow the OM-CNS as a promising and environmental-friendly adsorbent for CO2 capture and separation under practical conditions.

  15. Ordered mesoporous silica prepared by quiescent interfacial growth method - effects of reaction chemistry

    Science.gov (United States)

    2013-01-01

    Acidic interfacial growth can provide a number of industrially important mesoporous silica morphologies including fibers, spheres, and other rich shapes. Studying the reaction chemistry under quiescent (no mixing) conditions is important for understanding and for the production of the desired shapes. The focus of this work is to understand the effect of a number of previously untested conditions: acid type (HCl, HNO3, and H2SO4), acid content, silica precursor type (TBOS and TEOS), and surfactant type (CTAB, Tween 20, and Tween 80) on the shape and structure of products formed under quiescent two-phase interfacial configuration. Results show that the quiescent growth is typically slow due to the absence of mixing. The whole process of product formation and pore structuring becomes limited by the slow interfacial diffusion of silica source. TBOS-CTAB-HCl was the typical combination to produce fibers with high order in the interfacial region. The use of other acids (HNO3 and H2SO4), a less hydrophobic silica source (TEOS), and/or a neutral surfactant (Tweens) facilitate diffusion and homogenous supply of silica source into the bulk phase and give spheres and gyroids with low mesoporous order. The results suggest two distinct regions for silica growth (interfacial region and bulk region) in which the rate of solvent evaporation and local concentration affect the speed and dimension of growth. A combined mechanism for the interfacial bulk growth of mesoporous silica under quiescent conditions is proposed. PMID:24237719

  16. Thermal and mechanical properties of novel nanocomposites from modified ordered mesoporous carbon FDU-15 and poly(methyl methacrylate)

    Energy Technology Data Exchange (ETDEWEB)

    Mohammadnezhad, Gholamhossein, E-mail: mohammadnezhad@cc.iut.ac.ir; Dinari, Mohammad, E-mail: dinari@cc.iut.ac.ir; Soltani, Roozbeh; Bozorgmehr, Zahra

    2015-08-15

    Graphical abstract: - Highlights: • The surface of mesoporous carbon, FDU-15, was modified by 3-mercaptopropyl-trimethoxysilane. • Nanocomposites of PMMA and modified FDU-15 were prepared by solution polymerization. • XRD shows that modified mesoporous FDU-15 has an ordered hexagonal mesostructure. • TEM and SEM images confirm the presence of large pores and ordered mesostructure. • Mechanical data indicated improvement in the tensile strength and modulus. - Abstract: With its well-ordered pore structure, high specific surface area and tunable pore diameters, ordered mesoporous carbons are suitable for applications in many areas of modern science and technology. In the present investigation, an ultrasonic irradiation was used for the modification of the mesoporous carbon FDU-15. Three nanocomposite films of the poly(methyl methacrylate) (PMMA) and modified FDU-15 were prepared by solution polymerization technique. The surface morphology and thermal and mechanical properties of the hybrid materials were evaluated by different methods. X-ray diffraction patterns showed that modified mesoporous FDU-15 had an ordered hexagonal mesostructure. Transmission electron microscopy (TEM) and field emission-scanning electron microscopy images confirmed the presence of large pores and a relatively ordered mesostructure for the functionalized materials. Thermogravimetric analysis data also revealed that the onset of decomposition temperature of the nanocomposites was higher than that of pristine PMMA, shifting toward higher temperatures as the amount of modified-FDU was increased. TEM images showed the well-ordered hexagonal arrays of mesopores FDU-15. Mechanical data indicated the improvement in the tensile strength and modulus with the modified FDU-15 loading. The film containing 1 wt.% of modified FDU-15 had a tensile strength of the order of 42 MPa, relative to the 28 MPa of the pristine PMMA.

  17. Thermal and mechanical properties of novel nanocomposites from modified ordered mesoporous carbon FDU-15 and poly(methyl methacrylate)

    International Nuclear Information System (INIS)

    Mohammadnezhad, Gholamhossein; Dinari, Mohammad; Soltani, Roozbeh; Bozorgmehr, Zahra

    2015-01-01

    Graphical abstract: - Highlights: • The surface of mesoporous carbon, FDU-15, was modified by 3-mercaptopropyl-trimethoxysilane. • Nanocomposites of PMMA and modified FDU-15 were prepared by solution polymerization. • XRD shows that modified mesoporous FDU-15 has an ordered hexagonal mesostructure. • TEM and SEM images confirm the presence of large pores and ordered mesostructure. • Mechanical data indicated improvement in the tensile strength and modulus. - Abstract: With its well-ordered pore structure, high specific surface area and tunable pore diameters, ordered mesoporous carbons are suitable for applications in many areas of modern science and technology. In the present investigation, an ultrasonic irradiation was used for the modification of the mesoporous carbon FDU-15. Three nanocomposite films of the poly(methyl methacrylate) (PMMA) and modified FDU-15 were prepared by solution polymerization technique. The surface morphology and thermal and mechanical properties of the hybrid materials were evaluated by different methods. X-ray diffraction patterns showed that modified mesoporous FDU-15 had an ordered hexagonal mesostructure. Transmission electron microscopy (TEM) and field emission-scanning electron microscopy images confirmed the presence of large pores and a relatively ordered mesostructure for the functionalized materials. Thermogravimetric analysis data also revealed that the onset of decomposition temperature of the nanocomposites was higher than that of pristine PMMA, shifting toward higher temperatures as the amount of modified-FDU was increased. TEM images showed the well-ordered hexagonal arrays of mesopores FDU-15. Mechanical data indicated the improvement in the tensile strength and modulus with the modified FDU-15 loading. The film containing 1 wt.% of modified FDU-15 had a tensile strength of the order of 42 MPa, relative to the 28 MPa of the pristine PMMA

  18. MCM-41 ordered mesoporous molecular sieves synthesis and characterization

    Directory of Open Access Journals (Sweden)

    Rogério A.A. Melo

    1999-07-01

    Full Text Available The aim of this work was to study the hydrothermal synthesis of Si and SiAlMCM-41 performed under both autogenic pressure and refluxing conditions. XRD data showed that the MCM-41 phase may be formed by both processes and that the synthesized material in the presence of Al and/or under reflux presents the hexagonally arrangement of less ordered mesopores. However, as verified by XRD and physisorption data, the order was improved with higher synthesis times. 29Si and 1H - 29Si C/P MAS NMR spectra showed that a great part of the Si atoms exists as silanol groups which originate resonance peaks at -110, -100 and -91 ppm. The presence of Al atoms may generate Si(3Si, Al and Si(2Si, 2Al environments which might be contributing to resonance peaks at -100 and -91 ppm. The 27Al MAS NMR spectrum of the as synthesized AlSiMCM-41 showed a resonance peak of tetrahedral framework aluminum close to 53 ppm and two others, one close to 14 ppm attributed to Al(H2O6+3 species and the other a weak signal close to 32 ppm attributed to pentacoordinated Al. 27Al MAS NMR spectra of the calcined sample showed a peak at 0 ppm corresponding to an hexacoordinated extra-framework aluminum formed during calcination.

  19. Facile fabrication of ordered mesoporous graphitic carbon nitride for RhB photocatalytic degradation

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Lei; Zhang, Anfeng [State Key Laboratory of Fine Chemicals, PSU-DUT Joint Center for Energy Research, School of Chemical Engineering, Dalian University of Technology, Dalian 116024 (China); Janik, Michael J. [EMS Energy Institute, PSU-DUT Joint Center for Energy Research and Department of Energy & Mineral Engineering, Pennsylvania State University, University Park, PA 16802 (United States); Li, Keyan [State Key Laboratory of Fine Chemicals, PSU-DUT Joint Center for Energy Research, School of Chemical Engineering, Dalian University of Technology, Dalian 116024 (China); Song, Chunshan [State Key Laboratory of Fine Chemicals, PSU-DUT Joint Center for Energy Research, School of Chemical Engineering, Dalian University of Technology, Dalian 116024 (China); EMS Energy Institute, PSU-DUT Joint Center for Energy Research and Department of Energy & Mineral Engineering, Pennsylvania State University, University Park, PA 16802 (United States); Guo, Xinwen, E-mail: guoxw@dlut.edu.cn [State Key Laboratory of Fine Chemicals, PSU-DUT Joint Center for Energy Research, School of Chemical Engineering, Dalian University of Technology, Dalian 116024 (China)

    2017-02-28

    Highlights: • Ordered mesoporous graphitic carbon nitrides with S{sub BET} = 279.3 m{sup 2}/g were prepared. • Enhanced photocatalytic activity and reusability were presented. • Improved S{sub BET} and charge carrier separation efficiency contribute to the activity. - Abstract: Ordered mesoporous graphitic carbon nitrides were prepared by directly condensing the uniform mixtures of melamine and KIT-6. After removal of the KIT-6 sacrificial template, the carbon nitrides were characterized with TEM, N{sub 2} physical adsorption, XRD, FT-IR, XPS, UV–vis and PL spectrometries, and tested for their RhB photocatalytic degradation activity. Together, these characterizations confirmed the as-prepared tunable mesoporous materials with enhanced charge separation efficiency and superior photocatalytic performance. Compared with a conventional bulk g-C{sub 3}N{sub 4}, ordered mesoporous g-C{sub 3}N{sub 4} exhibits a larger specific surface area of 279.3 m{sup 2}/g and a pore size distribution about 4.0 nm and 13.0 nm. Meanwhile, the reduced bandgap energy of 2.77 eV and lower photogenerated electron-hole pair recombination frequency were evidenced by UV–Vis and PL spectra. The RhB photocatalytic degradation activity maximizes with a mass ratio of KIT-6/melamine of 80% (KCN80), and the kinetic constant reaches 0.0760 min{sup −1} which is 16 times higher than that of the bulk sample. Reusability of KCN80 was demonstrated by a lack of evident deactivation after three consecutive reaction periods. The direct condensation of the KIT-6 and melamine mixture does not require pre-casting of the precursor into the pore system of the templates. Owing to its high product yield, improved S{sub BET}, reduced bandgap energy and limited charge recombination, the facile-prepared ordered mesoporous g-C{sub 3}N{sub 4} is a practical candidate for further modification.

  20. Construction of order mesoporous (Eu–La)/ZnO composite material and its luminescent characters

    Energy Technology Data Exchange (ETDEWEB)

    Bao, Na; Liu, Yu; Li, Zi-Wei [School of Chemistry & Environmental Engineering, Changchun University of Science and Technology, Changchun 130022 (China); Yu, Hui, E-mail: yh2001101@163.com [School of Chemistry & Environmental Engineering, Changchun University of Science and Technology, Changchun 130022 (China); Bai, Hao-tian [School of Chemistry & Environmental Engineering, Changchun University of Science and Technology, Changchun 130022 (China); Xia, Long, E-mail: xialong_aron@163.com [School of Materials Science and Engineering, Harbin Institute of Technology at Weihai, Weihai 264209 (China); Feng, Da-wei [Changchun University of Science and Technology Science Park, Changchun 130022 (China); Guangdong College of Business and Technology, Zhaoqing 526020 (China); Zhang, Hong-bo; Dong, Xiang-ting; Wang, Tian-yang; Han, Ji; Wu, Rong-yi; Zhang, Qi [School of Chemistry & Environmental Engineering, Changchun University of Science and Technology, Changchun 130022 (China)

    2016-09-15

    For the first time, the order mesoporous zinc oxide was synthesized by a soft template synthesis method. The Eu and La phosphate were introduced into the prepared mesoporous zinc oxide by the high temperature solid phase method, and got the mesoporous rare earth/zinc oxide composite materials. The luminescence characters of the materials were studied. The influences of La to Eu luminescent properties had been studied, and the optimum proportion of Eu and La was discussed. The influences of La and Eu to ZnO luminescence properties were also been studied. La phosphate had the large influence to Eu luminescent. ZnO had a strong emission peak at 469 nm, which overlapped with the {sup 7}F{sub 0}–{sup 5}D{sub 2} transition excitation peak of Eu at 465 nm. It indicated that the effective energy transfer happened between ZnO and Eu, which strongly enhanced the luminescence intensity of Eu. At the same time, the Eu and La phosphates could regulate the defect density of ZnO, which could regulate the luminescent intensity of ZnO, and realized the adjustment of luminescent color between green and red light.

  1. A rational repeating template method for synthesis of 2D hexagonally ordered mesoporous precious metals.

    Science.gov (United States)

    Takai, Azusa; Doi, Yoji; Yamauchi, Yusuke; Kuroda, Kazuyuki

    2011-03-01

    A repeating template method is presented for the synthesis of mesoporous metals with 2D hexagonal mesostructures. First, a silica replica (i.e., silica nanorods arranged periodically) is prepared by using 2D hexagonally ordered mesoporous carbon as the template. After that, the obtained silica replica is used as the second template for the preparation of mesoporous ruthenium. After the ruthenium species are introduced into the silica replica, the ruthenium species are then reduced by a vapor-infiltration method by using the reducing agent dimethylamine borane. After the ruthenium deposition, the silica is chemically removed. Analysis by transmission and scanning electron microscopies, a nitrogen-adsorption-desorption isotherm, and small-angle X-ray scattering revealed that the mesoporous ruthenium had a 2D hexagonal mesostructure, although the mesostructural ordering is decreased compared to that of the original mesoporous carbon template. This method is widely applicable to other metal systems. By changing the metal species introduced into the silica replica, several mesoporous metals (palladium and platinum) can be synthesized. Ordered mesoporous ruthenium and palladium, which are not easily attainable by the soft-templating methods, can be prepared. This study has overcome the composition variation limitations of the soft-templating method. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Thermal and mechanical properties of novel nanocomposites from modified ordered mesoporous carbon FDU-15 and poly(methyl methacrylate)

    Science.gov (United States)

    Mohammadnezhad, Gholamhossein; Dinari, Mohammad; Soltani, Roozbeh; Bozorgmehr, Zahra

    2015-08-01

    With its well-ordered pore structure, high specific surface area and tunable pore diameters, ordered mesoporous carbons are suitable for applications in many areas of modern science and technology. In the present investigation, an ultrasonic irradiation was used for the modification of the mesoporous carbon FDU-15. Three nanocomposite films of the poly(methyl methacrylate) (PMMA) and modified FDU-15 were prepared by solution polymerization technique. The surface morphology and thermal and mechanical properties of the hybrid materials were evaluated by different methods. X-ray diffraction patterns showed that modified mesoporous FDU-15 had an ordered hexagonal mesostructure. Transmission electron microscopy (TEM) and field emission-scanning electron microscopy images confirmed the presence of large pores and a relatively ordered mesostructure for the functionalized materials. Thermogravimetric analysis data also revealed that the onset of decomposition temperature of the nanocomposites was higher than that of pristine PMMA, shifting toward higher temperatures as the amount of modified-FDU was increased. TEM images showed the well-ordered hexagonal arrays of mesopores FDU-15. Mechanical data indicated the improvement in the tensile strength and modulus with the modified FDU-15 loading. The film containing 1 wt.% of modified FDU-15 had a tensile strength of the order of 42 MPa, relative to the 28 MPa of the pristine PMMA.

  3. Ordered mesoporous MFe(2)O(4) (M = Co, Cu, Mg, Ni, Zn) thin films with nanocrystalline walls, uniform 16 nm diameter pores and high thermal stability: template-directed synthesis and characterization of redox active trevorite.

    Science.gov (United States)

    Haetge, Jan; Suchomski, Christian; Brezesinski, Torsten

    2010-12-20

    In this paper, we report on ordered mesoporous NiFe(2)O(4) thin films synthesized via co-assembly of hydrated ferric nitrate and nickel chloride with an amphiphilic diblock copolymer, referred to as KLE. We establish that the NiFe(2)O(4) samples are highly crystalline after calcination at 600 °C, and that the conversion of the amorphous inorganic framework comes at little cost to the ordering of the high quality cubic network of pores averaging 16 nm in diameter. We further show that the synthesis method employed in this work can be readily extended to other ferrites, such as CoFe(2)O(4), CuFe(2)O(4), MgFe(2)O(4), and ZnFe(2)O(4), which could pave the way for innovative device design. While this article focuses on the self-assembly and characterization of these materials using various state-of-the-art techniques, including electron microscopy, grazing incidence small-angle X-ray scattering (GISAXS), time-of-flight secondary ion mass spectrometry (TOF-SIMS), X-ray photoelectron spectroscopy (XPS), as well as UV-vis and Raman spectroscopy, we also examine the electrochemical properties and show the benefits of combining a continuous mesoporosity with nanocrystalline films. KLE-templated NiFe(2)O(4) electrodes exhibit reasonable levels of lithium ion storage at short charging times which stem from facile pseudocapacitance.

  4. Pore ordering in mesoporous matrices induced by different directing agents

    Czech Academy of Sciences Publication Activity Database

    Putz, A.-M.; Cecilia, S.; Ianasi, C.; Dudás, Z.; Székely, N. K.; Plocek, Jiří; Sfarloaga, P.; Sacarescu, L.; Almásy, L.

    2015-01-01

    Roč. 22, č. 2 (2015), s. 321-331 ISSN 1380-2224 Institutional support: RVO:61388980 Keywords : Mesoporous silica * MCM-41 * Dodecyl-trimethyl ammonium bromide * Hexadecyl-trimethylammonium bromide Subject RIV: CA - Inorganic Chemistry Impact factor: 1.385, year: 2015

  5. Synthesis of magnetic ordered mesoporous carbon (Fe-OMC) adsorbent and its evaluation for fuel desulfurization

    Energy Technology Data Exchange (ETDEWEB)

    Farzin Nejad, N., E-mail: Farzinnejadn@ripi.ir [Petroleum Refining Technology Development Division, Research Institute of Petroleum Industry, Tehran 14857-33111 (Iran, Islamic Republic of); Shams, E.; Amini, M.K. [Department of Chemistry, University of Isfahan, Isfahan 81746-73441 (Iran, Islamic Republic of)

    2015-09-15

    In this work, magnetic ordered mesoporous carbon adsorbent was synthesized using soft templating method to adsorb sulfur from model oil (dibenzothiophene in n-hexane). Through this research, pluronic F-127, resorcinol-formaldehyde and hydrated iron nitrate were respectively used as soft template, carbon source and iron source. The adsorbent was characterized by X-ray diffraction, nitrogen adsorption–desorption isotherm and transmission electron microscopy. Nitrogen adsorption–desorption measurement revealed the high surface area (810 m{sup 2} g{sup −1}), maxima pore size of 3.3 nm and large pore volume (1.01 cm{sup 3} g{sup −1}) of the synthesized sample. The adsorbent showed a maximum adsorption capacity of 111 mg dibenzothiophene g{sup −1} of adsorbent. Sorption process was described by the pseudo-second-order rate equation and could be better fitted by the Freundlich model, showing the heterogeneous feature of the adsorption process. In addition, the adsorption capacity of regenerated adsorbent was 78.6% of the initial level, after five regeneration cycles. - Highlights: • Adsorptive desulfurization of model oil with magnetic ordered mesoporous carbon adsorbent, Fe-OMC, was studied. • Maximum adsorption capacity (q{sub max}) of Fe-OMC for DBT was found to be 111.1 mg g{sup −1}. • Freundlich isotherm best represents the equilibrium adsorption data. • Rate of DBT adsorption process onto Fe-OMC is controlled by at least two steps.

  6. Synthesis of magnetic ordered mesoporous carbon (Fe-OMC) adsorbent and its evaluation for fuel desulfurization

    International Nuclear Information System (INIS)

    Farzin Nejad, N.; Shams, E.; Amini, M.K.

    2015-01-01

    In this work, magnetic ordered mesoporous carbon adsorbent was synthesized using soft templating method to adsorb sulfur from model oil (dibenzothiophene in n-hexane). Through this research, pluronic F-127, resorcinol-formaldehyde and hydrated iron nitrate were respectively used as soft template, carbon source and iron source. The adsorbent was characterized by X-ray diffraction, nitrogen adsorption–desorption isotherm and transmission electron microscopy. Nitrogen adsorption–desorption measurement revealed the high surface area (810 m 2 g −1 ), maxima pore size of 3.3 nm and large pore volume (1.01 cm 3 g −1 ) of the synthesized sample. The adsorbent showed a maximum adsorption capacity of 111 mg dibenzothiophene g −1 of adsorbent. Sorption process was described by the pseudo-second-order rate equation and could be better fitted by the Freundlich model, showing the heterogeneous feature of the adsorption process. In addition, the adsorption capacity of regenerated adsorbent was 78.6% of the initial level, after five regeneration cycles. - Highlights: • Adsorptive desulfurization of model oil with magnetic ordered mesoporous carbon adsorbent, Fe-OMC, was studied. • Maximum adsorption capacity (q max ) of Fe-OMC for DBT was found to be 111.1 mg g −1 . • Freundlich isotherm best represents the equilibrium adsorption data. • Rate of DBT adsorption process onto Fe-OMC is controlled by at least two steps

  7. Improved antimicrobial property and controlled drug release kinetics of silver sulfadiazine loaded ordered mesoporous silica

    Directory of Open Access Journals (Sweden)

    Suman Jangra

    2016-09-01

    Full Text Available The present study deals with the loading of silver sulfadiazine into ordered mesoporous silica material by post-impregnation method and its effect on the in vitro release kinetics and antimicrobial property of the drug. The formulated SBA-15 silica material with rope-like morphology and SBA-15-silver sulfadiazine (SBA-AgSD were characterized by UV–visible spectrophotometer, small and wide-angle powder X-ray diffraction (PXRD, field emission scanning electron microscope (FESEM and high resolution transmission electron microscope (HRTEM. Thermo-gravimetric analysis of SBA-AgSD revealed a high loading amount of 52.87%. Nitrogen adsorption–desorption analysis confirmed the drug entrapment into host material by revealing a reduced surface area (214 m2/g and pore diameter (6.7 nm of the SBA-AgSD. The controlled release of silver sulfadiazine drug from the mesoporous silica to simulated gastric, intestinal and body fluids was evaluated. The Korsmeyer–Peppas model fits the drug release data with the non-Fickian diffusion model and zero order kinetics of SBA-AgSD. The antibacterial performance of the SBA-AgSD was evaluated with respect to Staphylococcus aureus, Bacillus subtilis and Pseudomonas aeruginosa. The controlled drug delivery of the SBA-AgSD revealed improved antibacterial activity, thus endorsing its applicability in effective wound dressing.

  8. Size Effect of Ordered Mesoporous Carbon Nanospheres for Anodes in Li-Ion Battery

    Directory of Open Access Journals (Sweden)

    Pei-Yi Chang

    2015-12-01

    Full Text Available The present work demonstrates the application of various sizes of ordered mesoporous carbon nanospheres (OMCS with diameters of 46–130 nm as an active anode material for Li-ion batteries (LIB. The physical and chemical properties of OMCS have been evaluated by performing scanning electron microscopy (SEM, transmission electron microscopy (TEM, N2 adsorption-desorption analysis; small-angle scattering system (SAXS and X-ray diffraction (XRD. The electrochemical analysis of using various sizes of OMCS as anode materials showed high capacity and rate capability with the specific capacity up to 560 mA·h·g−1 at 0.1 C after 85 cycles. In terms of performance at high current rate compared to other amorphous carbonaceous materials; a stable and extremely high specific capacity of 240 mA·h·g−1 at 5 C after 15 cycles was achieved. Such excellent performance is mainly attributed to the suitable particle size distribution of OMCS and intimate contact between OMCS and conductive additives; which can be supported from the TEM images. Results obtained from this study clearly indicate the excellence of size distribution of highly integrated mesoporous structure of carbon nanospheres for LIB application.

  9. Systematically controlled pore system of ordered mesoporous carbons using phosphoric acid as the in situ generated catalysts for carbonization and activation

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Xing; Lee, Chang Hyun; Kim, Jin Hoe; You, Dae Jong; Shon, Jeong Kuk; Kim, Ji Man [Dept. of Chemistry, Sungkyunkwan University, Suwon (Korea, Republic of); Pak, Chan Ho [Fuel Cell Group, Corporate R and D Center, Samsung SDI Co. Ltd., Yongin (Korea, Republic of)

    2015-08-15

    We report on a facile synthesis of the ordered mesoporous carbon (OMC) materials with systematically controlled microporosity and mesoporosity simultaneously through the nano-replication route using phosphoric acid as the acid catalyst and activation agent. The use of phosphoric acid affects the pore structures of OMC materials, such as the formation of numerous micropores by activation of the carbon framework and the enlargement of mesopores by spontaneous phase separation during the carbonization. The mesopore sizes, surface areas, total pore volumes, and micropore volumes of the OMC materials are highly dependent on the phosphoric acid content and can be systematically controlled in the range 3.7–7.5 nm, 1027–2782 m{sup 2} g{sup -1}, 1.12–3.53 cm{sup 3} g{sup -1} and 0.34–0.95 cm{sup 3} g{sup -1}, respectively. OMC materials with systematically controlled pore structures were successfully synthesized using phosphoric acid as the carbonization catalyst and mesoporous silica materials with cubic Ia3d and 2-D hexagonal mesostructures as the templates. The phosphoric acid in the synthesis of ordered mesoporous carbon materials acts as the chemical activating agent for micropore generation of the carbon framework and pore-expanding agent for controlling of mesopore size, in addition to functioning as the acid catalyst. The present synthesis pathway is very useful for preparing OMC materials with tunable mesopore sizes and well-developed microporosities at the same time.

  10. Gold and palladium adsorption from leached electronic scrap using ordered mesoporous carbon nanoscaffolds

    Energy Technology Data Exchange (ETDEWEB)

    McDowell, Rocklan; Dutech, Guy

    2014-09-01

    Ordered mesoporous carbon (OMC) nanoscaffolds are engineered agglomerates of carbon nanotubes held together by small carbon nanofibers with uniform pore sizes, high pore volume, and high channel permeability. These materials exhibit very high affinity for the adsorption of gold from aqueous acidic mixtures. The efficiency of gold recovery is comparable to those typically accomplished using biopolymer-based adsorbents. The adsorption efficiency for other precious metals such as palladium and platinum is lower. Studies on the precious metal (Au, Pd) adsorption on OMC materials from actual liquors of leached electronics will be presented. Adsorption properties will be compared for several different sorbents used for the recovery of precious metals. The leach liquor compositions for three different types of electronic scrap materials (personal computer board, cell phone and tv input/output board) will be presented. The sorption efficiencies for Au, Pd, together with a spectrum of competing and non-competing metals, from such leach mixtures will be compared.

  11. Gold and palladium adsorption from leached electronic scrap using ordered mesoporous carbon nanoscaffolds

    International Nuclear Information System (INIS)

    McDowell, Rocklan; Dutech, Guy

    2014-01-01

    Ordered mesoporous carbon (OMC) nanoscaffolds are engineered agglomerates of carbon nanotubes held together by small carbon nanofibers with uniform pore sizes, high pore volume, and high channel permeability. These materials exhibit very high affinity for the adsorption of gold from aqueous acidic mixtures. The efficiency of gold recovery is comparable to those typically accomplished using biopolymer-based adsorbents. The adsorption efficiency for other precious metals such as palladium and platinum is lower. Studies on the precious metal (Au, Pd) adsorption on OMC materials from actual liquors of leached electronics will be presented. Adsorption properties will be compared for several different sorbents used for the recovery of precious metals. The leach liquor compositions for three different types of electronic scrap materials (personal computer board, cell phone and tv input/output board) will be presented. The sorption efficiencies for Au, Pd, together with a spectrum of competing and non-competing metals, from such leach mixtures will be compared.

  12. Pore Structure Control of Ordered Mesoporous Silica Film Using Mixed Surfactants

    Directory of Open Access Journals (Sweden)

    Tae-Jung Ha

    2011-01-01

    Full Text Available Materials with nanosized and well-arranged pores have been researched actively in order to be applied to new technology fields. Especially, mesoporous material containing various pore structures is expected to have different pore structure. To form a mixed pore structure, ordered mesoporous silica films were prepared with a mixture of surfactant; Brij-76 and P-123 block copolymer. In mixed surfactant system, mixed pore structure was observed in the region of P-123/(Brij-76 + P-123 with about 50.0 wt.% while a single pore structure was observed in regions which have large difference in ratio between Brij-76 and P-123 through the X-ray diffraction analysis. Regardless of surfactant ratio, porosity was retained almost the same. It is expected that ordered mesoporous silica film with mixed pore structure can be one of the new materials which has distinctive properties.

  13. Hierarchical mesoporous/microporous carbon with graphitized frameworks for high-performance lithium-ion batteries

    Directory of Open Access Journals (Sweden)

    Yingying Lv

    2014-11-01

    Full Text Available A hierarchical meso-/micro-porous graphitized carbon with uniform mesopores and ordered micropores, graphitized frameworks, and extra-high surface area of ∼2200 m2/g, was successfully synthesized through a simple one-step chemical vapor deposition process. The commercial mesoporous zeolite Y was utilized as a meso-/ micro-porous template, and the small-molecule methane was employed as a carbon precursor. The as-prepared hierarchical meso-/micro-porous carbons have homogeneously distributed mesopores as a host for electrolyte, which facilitate Li+ ions transport to the large-area micropores, resulting a high reversible lithium ion storage of 1000 mA h/g and a high columbic efficiency of 65% at the first cycle.

  14. Hierarchically ordered mesoporous carbon/graphene composites as supercapacitor electrode materials.

    Science.gov (United States)

    Song, Yanjie; Li, Zhu; Guo, Kunkun; Shao, Ting

    2016-08-25

    Hierarchically ordered mesoporous carbon/graphene (OMC/G) composites have been fabricated by means of a solvent-evaporation-induced self-assembly (EISA) method. The structures of these composites are characterized by X-ray diffraction, transmission electron microscopy, Raman spectroscopy and nitrogen adsorption-desorption at 77 K. These results indicate that OMC/G composites possess the hierarchically ordered hexagonal p6mm mesostructure with the lattice unit parameter and pore diameter close to 10 nm and 3 nm, respectively. The specific surface area of OMC/G composites after KOH activation is high up to 2109.2 m(2) g(-1), which is significantly greater than OMC after activation (1474.6 m(2) g(-1)). Subsequently, the resulting OMC/G composites as supercapacitor electrode materials exhibit an outstanding capacitance as high as 329.5 F g(-1) in 6 M KOH electrolyte at a current density of 0.5 A g(-1), which is much higher than both OMC (234.2 F g(-1)) and a sample made by mechanical mixing of OMC with graphene (217.7 F g(-1)). In addition, the obtained OMC/G composites display good cyclic stability, and the final capacitance retention is approximately 96% after 5000 cycles. These ordered mesopores in the OMC/G composites are beneficial to the accessibility and rapid diffusion of the electrolyte, while graphene in OMC/G composites can also facilitate the transport of electrons during the processes of charging and discharging owing to its high conductivity, thereby leading to an excellent energy storage performance. The method demonstrated in this work would open up a new route to design and develop graphene-based architectures for supercapacitor applications.

  15. Synthesis of titania modified silica-pillared clay (SPC) with highly ordered interlayered mesoporous structure for removing toxic metal ion Cr(VI) from aqueous state

    Energy Technology Data Exchange (ETDEWEB)

    Mao, Huihui, E-mail: maohuihui_beijing@126.com [State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029 (China); Jiangsu Key Laboratory of Advanced Catalytic Materials and Technology, Changzhou University, Changzhou, Jiangsu Province 213164 (China); Zhu, Kongnan [Jiangsu Key Laboratory of Advanced Catalytic Materials and Technology, Changzhou University, Changzhou, Jiangsu Province 213164 (China); Li, Baoshan, E-mail: bsli@mail.buct.edu.cn [State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029 (China); Yao, Chao; Kong, Yong [Jiangsu Key Laboratory of Advanced Catalytic Materials and Technology, Changzhou University, Changzhou, Jiangsu Province 213164 (China)

    2014-02-15

    Titanium-functionalized silica-pillared clays synthesized through post synthetic route was utilized as adsorbers for the removal of Cr(VI) ions from aqueous solutions under different temperatures and initial concentrations. The starting mesostructured silica-pillared clay is assembled by intragallery ammonia-catalyzed hydrolysis of tetraethoxysilane using cationic surfactant as gallery template, and subsequently, the formed interlayered pore walls were decorated with nano-sized TiO{sub 2} particle through organic titanium functionalization process. The kind of structural transformation has been confirmed by X-ray diffraction (XRD), nitrogen adsorption–desorption isotherms, Fourier transform infrared (FT-IR) analysis, UV–vis diffuse reflectance spectroscopy (DRS), elemental analysis (XRF), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Such results indicate that most of the grafted titanium species was combined with Si–OH on the surface of gallery pores. By changing the concentration of organic titanium source during synthesis, the porous structure system is effected. Under suitable conditions, these materials exhibit high adsorption capacity and efficiency. Qualitative estimates of the thermodynamic parameters showed that the overall adsorption process is spontaneous (ΔG° < 0) and endothermic (ΔH° > 0). The adsorption isotherms of Cr(VI) on titanium-functionalized silica-pillared clay were best fitted by Redlich–Peterson models. Detail results of thermodynamics and kinetics are also presented.

  16. Synthesis of titania modified silica-pillared clay (SPC) with highly ordered interlayered mesoporous structure for removing toxic metal ion Cr(VI) from aqueous state

    International Nuclear Information System (INIS)

    Mao, Huihui; Zhu, Kongnan; Li, Baoshan; Yao, Chao; Kong, Yong

    2014-01-01

    Titanium-functionalized silica-pillared clays synthesized through post synthetic route was utilized as adsorbers for the removal of Cr(VI) ions from aqueous solutions under different temperatures and initial concentrations. The starting mesostructured silica-pillared clay is assembled by intragallery ammonia-catalyzed hydrolysis of tetraethoxysilane using cationic surfactant as gallery template, and subsequently, the formed interlayered pore walls were decorated with nano-sized TiO 2 particle through organic titanium functionalization process. The kind of structural transformation has been confirmed by X-ray diffraction (XRD), nitrogen adsorption–desorption isotherms, Fourier transform infrared (FT-IR) analysis, UV–vis diffuse reflectance spectroscopy (DRS), elemental analysis (XRF), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Such results indicate that most of the grafted titanium species was combined with Si–OH on the surface of gallery pores. By changing the concentration of organic titanium source during synthesis, the porous structure system is effected. Under suitable conditions, these materials exhibit high adsorption capacity and efficiency. Qualitative estimates of the thermodynamic parameters showed that the overall adsorption process is spontaneous (ΔG° 0). The adsorption isotherms of Cr(VI) on titanium-functionalized silica-pillared clay were best fitted by Redlich–Peterson models. Detail results of thermodynamics and kinetics are also presented.

  17. An enzyme-assisted electrochemiluminescent biosensor developed on order mesoporous carbons substrate for ultrasensitive glyphosate sensing

    International Nuclear Information System (INIS)

    Zhang, Qingrong; Xu, Guifang; Gong, Lingshan; Dai, Hong; Zhang, Shupei; Li, Yilin; Lin, Yanyu

    2015-01-01

    In this paper, a strategy of developing a late-model and sensitive electrochemiluminescence (ECL) biosensor for glyphosate detection based on enzyme-assisted in situ generation of ZnS quantum dots (QDs) on ordered mesoporous carbons (OMC) substrate was proposed. OMC, as a typically ordered mesoporous carbon material, not only provides a protective microenvironment for enzyme to retain its structure and activity but also has a synergistic effect with chitosan for the absorption of Zn 2+ ions by virtue of its high surface area and high pore volume and thus employed as the matrix of proposed biosensor. Then horseradish peroxidase (HRP) was introduced to expedite the generation of ZnS QDs via accelerating the reduction of Na 2 S 2 O 3 with H 2 O 2 to yield H 2 S that reacted with Zn 2+ ions. Glyphosate, as a kind of organic pesticide with amine, carboxyl and phosphonate group which would coordinate strongly to metal ions, possessed the potential to inhibited the activity of HRP, because HRP contain iron (III) protoporphyrin IX (ferriprotoporphyrin IX) as the prosthetic group which would react with the amine, carboxyl and phosphonate group of glyphosate. Accordingly, the proposed ECL QDs biosensor was employed to determine the Gly and shown a wide linear range from 0.1 nM to 10 mM with excellent sensitivity, reproducibility and selectivity. Further, the half maximal inhibitory concentration (IC 50 ) and the Michaelis–Menten constant were studied, and all the results indicated that the proposed strategy is practicable and provide a new opportunity to develop novel ECL sensing platforms in various applications.

  18. Synthesis of Ordered Mesoporous CuO/CeO2 Composite Frameworks as Anode Catalysts for Water Oxidation

    Directory of Open Access Journals (Sweden)

    Vassiliki Markoulaki Ι

    2015-11-01

    Full Text Available Cerium-rich metal oxide materials have recently emerged as promising candidates for the photocatalytic oxygen evolution reaction (OER. In this article, we report the synthesis of ordered mesoporous CuO/CeO2 composite frameworks with different contents of copper(II oxide and demonstrate their activity for photocatalytic O2 production via UV-Vis light-driven oxidation of water. Mesoporous CuO/CeO2 materials have been successfully prepared by a nanocasting route, using mesoporous silica as a rigid template. X-ray diffraction, electron transmission microscopy and N2 porosimetry characterization of the as-prepared products reveal a mesoporous structure composed of parallel arranged nanorods, with a large surface area and a narrow pore size distribution. The molecular structure and optical properties of the composite materials were investigated with Raman and UV-Vis/NIR diffuse reflectance spectroscopy. Catalytic results indicated that incorporation of CuO clusters in the CeO2 lattice improved the photochemical properties. As a result, the CuO/CeO2 composite catalyst containing ~38 wt % CuO reaches a high O2 evolution rate of ~19.6 µmol·h−1 (or 392 µmol·h−1·g−1 with an apparent quantum efficiency of 17.6% at λ = 365 ± 10 nm. This OER activity compares favorably with that obtained from the non-porous CuO/CeO2 counterpart (~1.3 µmol·h−1 and pure mesoporous CeO2 (~1 µmol·h−1.

  19. Highly Aminated Mesoporous Silica Nanoparticles with Cubic Pore Structure

    KAUST Repository

    Suteewong, Teeraporn

    2011-01-19

    Mesoporous silica with cubic symmetry has attracted interest from researchers for some time. Here, we present the room temperature synthesis of mesoporous silica nanoparticles possessing cubic Pm3n symmetry with very high molar ratios (>50%) of 3-aminopropyl triethoxysilane. The synthesis is robust allowing, for example, co-condensation of organic dyes without loss of structure. By means of pore expander molecules, the pore size can be enlarged from 2.7 to 5 nm, while particle size decreases. Adding pore expander and co-condensing fluorescent dyes in the same synthesis reduces average particle size further down to 100 nm. After PEGylation, such fluorescent aminated mesoporous silica nanoparticles are spontaneously taken up by cells as demonstrated by fluorescence microscopy.

  20. Highly Aminated Mesoporous Silica Nanoparticles with Cubic Pore Structure

    KAUST Repository

    Suteewong, Teeraporn; Sai, Hiroaki; Cohen, Roy; Wang, Suntao; Bradbury, Michelle; Baird, Barbara; Gruner, Sol M.; Wiesner, Ulrich

    2011-01-01

    Mesoporous silica with cubic symmetry has attracted interest from researchers for some time. Here, we present the room temperature synthesis of mesoporous silica nanoparticles possessing cubic Pm3n symmetry with very high molar ratios (>50%) of 3-aminopropyl triethoxysilane. The synthesis is robust allowing, for example, co-condensation of organic dyes without loss of structure. By means of pore expander molecules, the pore size can be enlarged from 2.7 to 5 nm, while particle size decreases. Adding pore expander and co-condensing fluorescent dyes in the same synthesis reduces average particle size further down to 100 nm. After PEGylation, such fluorescent aminated mesoporous silica nanoparticles are spontaneously taken up by cells as demonstrated by fluorescence microscopy.

  1. Imprint-coating synthesis of selective functionalized ordered mesoporous sorbents for separation and sensors

    Science.gov (United States)

    Dai, Sheng; Burleigh, Mark C.; Shin, Yongsoon

    2001-01-01

    The present invention relates generally to mesoporous sorbent materials having high capacity, high selectivity, fast kinetics, and molecular recognition capability. The invention also relates to a process for preparing these mesoporous substrates through molecular imprinting techniques which differ from convention techniques in that a template molecule is bound to one end of bifunctional ligands to form a complex prior to binding of the bifunctional ligands to the substrate. The present invention also relates to methods of using the mesoporous sorbent materials, for example, in the separation of toxic metals from process effluents, paints, and other samples; detection of target molecules, such as amino acids, drugs, herbicides, fertilizers, and TNT, in samples; separation and/or detection of substances using chromatography; imaging agents; sensors; coatings; and composites.

  2. Cubic mesoporous Ag@CN: a high performance humidity sensor.

    Science.gov (United States)

    Tomer, Vijay K; Thangaraj, Nishanthi; Gahlot, Sweta; Kailasam, Kamalakannan

    2016-12-01

    The fabrication of highly responsive, rapid response/recovery and durable relative humidity (%RH) sensors that can precisely monitor humidity levels still remains a considerable challenge for realizing the next generation humidity sensing applications. Herein, we report a remarkably sensitive and rapid %RH sensor having a reversible response using a nanocasting route for synthesizing mesoporous g-CN (commonly known as g-C 3 N 4 ). The 3D replicated cubic mesostructure provides a high surface area thereby increasing the adsorption, transmission of charge carriers and desorption of water molecules across the sensor surfaces. Owing to its unique structure, the mesoporous g-CN functionalized with well dispersed catalytic Ag nanoparticles exhibits excellent sensitivity in the 11-98% RH range while retaining high stability, negligible hysteresis and superior real time %RH detection performances. Compared to conventional resistive sensors based on metal oxides, a rapid response time (3 s) and recovery time (1.4 s) were observed in the 11-98% RH range. Such impressive features originate from the planar morphology of g-CN as well as unique physical affinity and favourable electronic band positions of this material that facilitate water adsorption and charge transportation. Mesoporous g-CN with Ag nanoparticles is demonstrated to provide an effective strategy in designing high performance %RH sensors and show great promise for utilization of mesoporous 2D layered materials in the Internet of Things and next generation humidity sensing applications.

  3. Electrochemistry and electrocatalysis of polyoxometalate-ordered mesoporous carbon modified electrode

    International Nuclear Information System (INIS)

    Zhou Ming; Guo Liping; Lin Fanyun; Liu Haixia

    2007-01-01

    In this work, we have developed a convenient and efficient method for the functionalization of ordered mesoporous carbon (OMC) using polyoxometalate H 6 P 2 Mo 18 O 62 .xH 2 O (P 2 Mo 18 ). By the method, glassy carbon (GC) electrode modified with P 2 Mo 18 which was immobilized on the channel surface of OMC was prepared and characterized for the first time. The large specific surface area and porous structure of the modified OMC particles result in high heteropolyacid loading, and the P 2 Mo 18 entrapped in this order matrix is stable. Fourier transform infrared spectroscopy (FTIR), nitrogen adsorption-desorption isotherm and X-ray diffraction (XRD) were employed to give insight into the intermolecular interaction between OMC and P 2 Mo 18 . The electrochemical behavior of the modified electrode was studied in detail, including pH-dependence, stability and so on. The cyclic voltammetry (CV) and amperometry studies demonstrated that P 2 Mo 18 /OMC/GC electrode has high stability, fast response and good electrocatalytic activity for the reduction of nitrite, bromate, idonate, and hydrogen peroxide. The mechanism of catalysis on P 2 Mo 18 /OMC/GC electrode was discussed. Moreover, the development of our approach for OMC functionalization suggests the potential applications in catalysis, molecular electronics and sensors

  4. Adsorption removal of acid black 1 from aqueous solution using ordered mesoporous carbon

    Energy Technology Data Exchange (ETDEWEB)

    Peng, Xiaoming, E-mail: pengxiaoming70@126.com [School of Civil Engineering, Southeast University, Nanjing 210096 (China); Hu, Xijun [Department of Chemical and Biomolecular Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong,China (China); Fu, Dafang, E-mail: fdf@seu.edu.cn [School of Civil Engineering, Southeast University, Nanjing 210096 (China); Lam, Frank L.Y. [Department of Chemical and Biomolecular Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong,China (China)

    2014-03-01

    Highlights: • Ordered mesoporous carbon was prepared using template. • Ordered mesoporous carbon was introduced of N-containing group by Chemical vapor deposition method. • Modified CMK-3 have better adsorption capacity and efficiency than virgin CMK-3 to removal AB1 dye. - Abstract: A novel ordered mesoporous carbon CMK-3 and synthetic CMK-3 containing nitrogen functional groups by ammonia-treated were applied for acid black 1(AB1) dye adsorption. The ammonia-treated(chemical vapor deposition method) before and after CMK-3 were characterized by using a Micrometitics ASAP 2020 surface area analyzer (ASAP 2020), Fourier transform infrared spectrophotometer (FT–IR), X-ray Photoelectron Spectroscopy (XPS), transmission electron microscopy (TEM), scanning electron microscope (SEM) and equilibrium studies. This result indicates that the prepared CMK-3 and modified CMK-3 were almost uniform, as rope-like domains and their uniform mesopore with diameter centered at 3.2 nm and 3.7 nm. The FIIR analysis depicted that the presence of a variety of new basic functional groups on the modified CMK-3 surface. Several effect variables of pH, dye concentration and temperature were studied. The pseudo second-order model showed the fitter well to agree with the kinetic data. The experimental data were analyzed by the Langmuir and Freundlich models, with the latter found to closely the isotherm model. The adsorption kinetics was found to follow the pseudo-second-order kinetic model. The results show that CMK-3 using ammonia gas modified by thermal treatment system is an effective method to improvement capacity as it shows the highest adsorption capacity of AB1, as compared to the unmodified CMK-3 and the bamboo-based carbon, respectively.

  5. Nanocomposite of cobalt oxide and ordered mesoporous carbon as the electrode materials for supercapacitor

    Energy Technology Data Exchange (ETDEWEB)

    Xu, J.; Liu, P.; Zhao, J.; Feng, J.; Tang, B. [Shanghai Univ. of Engineering Science (China). College of Chemistry and Chemical Engineering

    2010-07-01

    An incipient wetness impregnation method was used to prepare a cobalt oxide ordered mesoporous carbon composite for use as an electrode in supercapacitor applications. The composite was then incorporated inside periodic nanoholes in the ordered mesoporous carbon (OMC). X-ray diffraction (XRD), transmission electron microscopy (TEM) and N{sub 2} adsorption-desorption isotherm analyses were used to characterize the structures of the samples. The specific capacitance of the synthesized materials was estimated using cyclic voltammetric (CV) analyses. The study showed that composites prepared using the new method exhibited a higher reversible specific capacitance of 594.8 F per g at a scan rate of 5 mV per second. The composite also showed good cyclic stability. Results suggested that the composite can be used as an electrode material in supercapacitors.

  6. Synthesis of magnetic ordered mesoporous carbon (Fe-OMC) adsorbent and its evaluation for fuel desulfurization

    Science.gov (United States)

    Farzin Nejad, N.; Shams, E.; Amini, M. K.

    2015-09-01

    In this work, magnetic ordered mesoporous carbon adsorbent was synthesized using soft templating method to adsorb sulfur from model oil (dibenzothiophene in n-hexane). Through this research, pluronic F-127, resorcinol-formaldehyde and hydrated iron nitrate were respectively used as soft template, carbon source and iron source. The adsorbent was characterized by X-ray diffraction, nitrogen adsorption-desorption isotherm and transmission electron microscopy. Nitrogen adsorption-desorption measurement revealed the high surface area (810 m2 g-1), maxima pore size of 3.3 nm and large pore volume (1.01 cm3 g-1) of the synthesized sample. The adsorbent showed a maximum adsorption capacity of 111 mg dibenzothiophene g-1 of adsorbent. Sorption process was described by the pseudo-second-order rate equation and could be better fitted by the Freundlich model, showing the heterogeneous feature of the adsorption process. In addition, the adsorption capacity of regenerated adsorbent was 78.6% of the initial level, after five regeneration cycles.

  7. Enhanced photo-catalytic activity of ordered mesoporous indium oxide nanocrystals in the conversion of CO2 into methanol.

    Science.gov (United States)

    Gondal, M A; Dastageer, M A; Oloore, L E; Baig, U; Rashid, S G

    2017-07-03

    Ordered mesoporous indium oxide nanocrystal (m-In 2 O 3 ) was synthesized by nanocasting technique, in which highly ordered mesoporous silca (SBA-15) was used as structural matrix. X-ray diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM) Brunauer-Emmett-Teller (BET) and Barrett-Joyner-Halanda (BJH) studies were carried out on m-In 2 O 3 and the results revealed that this material has a highly ordered mesoporous surface with reduced grain size, increased surface area and surface volume compared to the non porous indium oxide. The diffuse reluctance spectrum exhibited substantially improved light absorption efficiency in m-In 2 O 3 compared to normal indium oxide, however, no considerable change in the band gap energies of these materials was observed. When m-In 2 O 3 was used as a photo-catalyst in the photo-catalytic process of converting carbon dioxide (CO 2 ) into methanol under the pulsed laser radiation of 266-nm wavelengths, an enhanced photo-catalytic activity with the quantum efficiency of 4.5% and conversion efficiency of 46.3% were observed. It was found that the methanol production yield in this chemical process is as high as 485 µlg -1 h -1 after 150 min of irradiation, which is substantially higher than the yields reported in the literature. It is quite clear from the results that the introduction of mesoporosity in indium oxide, and the consequent enhancement of positive attributes required for a photo-catalyst, transformed photo-catalytically weak indium oxide into an effective photo-catalyst for the conversion of CO 2 into methanol.

  8. Nitrogen-Doped Ordered Mesoporous Carbon Supported Bimetallic PtCo Nanoparticles for Upgrading of Biophenolics.

    Science.gov (United States)

    Wang, Guang-Hui; Cao, Zhengwen; Gu, Dong; Pfänder, Norbert; Swertz, Ann-Christin; Spliethoff, Bernd; Bongard, Hans-Josef; Weidenthaler, Claudia; Schmidt, Wolfgang; Rinaldi, Roberto; Schüth, Ferdi

    2016-07-25

    Hydrodeoxygenation (HDO) is an attractive route for the upgrading of bio-oils produced from lignocellulose. Current catalysts require harsh conditions to effect HDO, decreasing the process efficiency in terms of energy and carbon balance. Herein we report a novel and facile method for synthesizing bimetallic PtCo nanoparticle catalysts (ca. 1.5 nm) highly dispersed in the framework of nitrogen-doped ordered mesoporous carbon (NOMC) for this reaction. We demonstrate that NOMC with either 2D hexagonal (p6m) or 3D cubic (Im3‾ m) structure can be easily synthesized by simply adjusting the polymerization temperature. We also demonstrate that PtCo/NOMC (metal loading: Pt 9.90 wt %; Co 3.31 wt %) is a highly effective catalyst for HDO of phenolic compounds and "real-world" biomass-derived phenolic streams. In the presence of PtCo/NOMC, full deoxygenation of phenolic compounds and a biomass-derived phenolic stream is achieved under conditions of low severity. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Immobilization induced molecular compression of ionic liquid in ordered mesoporous matrix

    Science.gov (United States)

    Tripathi, Alok Kumar; Singh, Rajendra Kumar

    2018-02-01

    In this work, ionic liquid (IL) 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide ([EMIM][FSI]) has been immobilized into ordered mesoporous silica MCM-41 by a physical imbibition process. Transmission electron microscopy confirms the filling of mesopores of MCM-41. The effect of IL content in MCM-41 was probed in terms of thermal stability, chemical interactions, and dielectric properties. N2-sorption results indicate the compression of the IL in the nanopores of MCM-41, which contributes to an increase of the melting point probed by differential scanning calorimetry. The quantum chemical calculations confirmed that the ion-ion interaction in ion-pairs of IL were preferred over the hydrogen bonding interaction in the presence of SiO2 molecules, and these interactions probably compress the molecular size in the nanopores of MCM-41. Strong interactions between IL and porous MCM-41 were suggested as the mechanism of this immobilization, which was characterized by FTIR and dielectric spectroscopy.

  10. Interconnected mesopores and high accessibility in UVM-7-like silicas

    Energy Technology Data Exchange (ETDEWEB)

    Perez-Cabero, Monica [Universitat de Valencia, Institut de Ciencia dels Materials (Spain); Hungria, Ana B. [Universidad de Cadiz, Departamento de Ciencia de Materiales, Ingenieria Metalurgica y Quimica Inorganica (Spain); Morales, Jose Manuel [Universitat de Valencia, Institut de Ciencia dels Materials (Spain); Tortajada, Marta; Ramon, Daniel [Biopolis S. L. (Spain); Moragues, Alaina; El Haskouri, Jamal; Beltran, Aurelio; Beltran, Daniel; Amoros, Pedro, E-mail: pedro.amoros@uv.es [Universitat de Valencia, Institut de Ciencia dels Materials (Spain)

    2012-08-15

    Nanoparticulated bimodal mesoporous silicas (NBS) have proved to constitute adequate supports in a variety of applications requiring enhanced accessibility to the active sites. Mass-transfer kinetics seems to be highly favoured in UVM-7-derived NBS materials. To understand the mass-diffusion phenomena throughout UVM-7-like supports requires well-grounded knowledge about their pore architecture. 3-D reconstructions of the UVM-7 mesostructure carried out by electron tomography reveal the existence of a true hierarchic connectivity involving both inter- and intra-nanoparticle pores. This connectivity makes self-supported nanoparticulated mesoporous bimodal carbon replicas of the supports feasible to obtaining by nanocasting. Both the temperature-induced mobility of gold nanodomains and the fast and efficient enzyme adsorption in UVM-7-like silicas are examples of non-constrained diffusion processes happening inside such an open network.

  11. Interconnected mesopores and high accessibility in UVM-7-like silicas

    International Nuclear Information System (INIS)

    Pérez-Cabero, Mónica; Hungría, Ana B.; Morales, José Manuel; Tortajada, Marta; Ramón, Daniel; Moragues, Alaina; El Haskouri, Jamal; Beltrán, Aurelio; Beltrán, Daniel; Amorós, Pedro

    2012-01-01

    Nanoparticulated bimodal mesoporous silicas (NBS) have proved to constitute adequate supports in a variety of applications requiring enhanced accessibility to the active sites. Mass-transfer kinetics seems to be highly favoured in UVM-7-derived NBS materials. To understand the mass-diffusion phenomena throughout UVM-7-like supports requires well-grounded knowledge about their pore architecture. 3-D reconstructions of the UVM-7 mesostructure carried out by electron tomography reveal the existence of a true hierarchic connectivity involving both inter- and intra-nanoparticle pores. This connectivity makes self-supported nanoparticulated mesoporous bimodal carbon replicas of the supports feasible to obtaining by nanocasting. Both the temperature-induced mobility of gold nanodomains and the fast and efficient enzyme adsorption in UVM-7-like silicas are examples of non-constrained diffusion processes happening inside such an open network.

  12. Functionalized magnetic mesoporous silica nanoparticles for U removal from low and high pH groundwater

    Energy Technology Data Exchange (ETDEWEB)

    Li, Dien, E-mail: dien.li@srs.gov [Savannah River National Laboratory, Aiken, SC 29808 (United States); Egodawatte, Shani [Department of Chemistry, University of Iowa, Iowa City, IA 52242 (United States); Kaplan, Daniel I. [Savannah River National Laboratory, Aiken, SC 29808 (United States); Larsen, Sarah C. [Department of Chemistry, University of Iowa, Iowa City, IA 52242 (United States); Serkiz, Steven M. [Savannah River National Laboratory, Aiken, SC 29808 (United States); Department of Physics and Astronomy, Clemson University, Clemson, SC 29634 (United States); Seaman, John C. [Savannah River Ecology Laboratory, University of Georgia, Aiken, SC 29802 (United States)

    2016-11-05

    Highlights: • Magnetic mesoporous silica nanoparticles were functionalized with organic molecules. • The functionalized nanoparticles had high surface areas and consistent pore sizes. • The functionalized nanoparticles were easily separated due to their magnetism. • They exhibited high capacity for uranium removal from low- or high-pH groundwater. - Abstract: U(VI) species display limited adsorption onto sediment minerals and synthetic sorbents in pH <4 or pH >8 groundwater. In this work, magnetic mesoporous silica nanoparticles (MMSNs) with magnetite nanoparticle cores were functionalized with various organic molecules using post-synthetic methods. The functionalized MMSNs were characterized using N{sub 2} adsorption-desorption isotherms, thermogravimetric analysis (TGA), transmission electron microscopy (TEM), {sup 13}C cross polarization and magic angle spinning (CPMAS) nuclear magnetic resonance (NMR) spectroscopy, and powder X-ray diffraction (XRD), which indicated that mesoporous silica (MCM-41) particles of 100–200 nm formed around a core of magnetic iron oxide, and the functional groups were primarily grafted into the mesopores of ∼3.0 nm in size. The functionalized MMSNs were effective for U removal from pH 3.5 and 9.6 artificial groundwater (AGW). Functionalized MMSNs removed U from the pH 3.5 AGW by as much as 6 orders of magnitude more than unfunctionalized nanoparticles or silica and had adsorption capacities as high as 38 mg/g. They removed U from the pH 9.6 AGW as much as 4 orders of magnitude greater than silica and 2 orders of magnitude greater than the unfunctionalized nanoparticles with adsorption capacities as high as 133 mg/g. These results provide an applied solution for treating U contamination that occurs at extreme pH environments and a scientific foundation for solving critical industrial issues related to environmental stewardship and nuclear power production.

  13. High-performance mesoporous LiFePO₄ from Baker's yeast.

    Science.gov (United States)

    Zhang, Xudong; Zhang, Xueguang; He, Wen; Sun, Caiyun; Ma, Jingyun; Yuan, Junling; Du, Xiaoyong

    2013-03-01

    Based on the biomineralization assembly concept, a simple and inexpensive biomimetic sol-gel method is found to synthesize high-performance mesoporous LiFePO(4) (HPM-LFP). The key step of this approach is to apply Baker's yeast cells as both a structural template and a biocarbon source. The formation mechanism of ordered hierarchical mesoporous network structure is revealed by characterizing its morphology and microstructure. The HPM-LFP exhibits outstanding electrochemical performances. The HPM-LFP has a high discharge capacity (about 153 mAh g(-1) at a 0.1 C rate), only 2% capacity loss from the initial value after 100 cycles at a current density of 0.1 C. This simple and potentially universal design strategy is currently being pursued in the synthesis of an ideal cathode-active material for high power applications. Copyright © 2012 Elsevier B.V. All rights reserved.

  14. Gas Sensing Properties of Ordered Mesoporous SnO2

    Directory of Open Access Journals (Sweden)

    Michael Tiemann

    2006-04-01

    Full Text Available We report on the synthesis and CO gas-sensing properties of mesoporoustin(IV oxides (SnO2. For the synthesis cetyltrimethylammonium bromide (CTABr wasused as a structure-directing agent; the resulting SnO2 powders were applied as films tocommercially available sensor substrates by drop coating. Nitrogen physisorption showsspecific surface areas up to 160 m2·g-1 and mean pore diameters of about 4 nm, as verifiedby TEM. The film conductance was measured in dependence on the CO concentration inhumid synthetic air at a constant temperature of 300 °C. The sensors show a high sensitivityat low CO concentrations and turn out to be largely insensitive towards changes in therelative humidity. We compare the materials with commercially available SnO2-basedsensors.

  15. Supercapacitors based on ordered mesoporous carbon derived from furfuryl alcohol: effect of the carbonized temperature.

    Science.gov (United States)

    Li, Na; Xu, Jianxiong; Chen, Han; Wang, Xianyou

    2014-07-01

    Supercapacitors are successfully prepared from ordered mesoporous carbon (OMC) synthesized by employing the mesoporous silica, SBA-15 as template and furfuryl alcohol as carbon source. It is found that the carbonized temperature greatly influences the physical properties of the synthesized mesoporous carbon materials. The optimal carbonized temperature is measured to be 600 degrees C under which OMC with the specific surface area of 1219 m2/g and pore volume of 1.31 cm3/g and average pore diameter of - 3 nm are synthesized. The OMC materials synthesized under different carbonized temperature are used as electrode material of supercapacitors and the electrochemical properties of the OMC materials are compared by using cyclic voltammetry, electrochemical impedance spectroscopy, galvanostatic charge-discharge and self-discharge tests. The results show that the electrochemical properties of the OMC materials are directly related to the specific surface area and pore volume of the mesoporous carbon and the electrode prepared from the OMC synthesized under the carbonized temperature of 600 degrees C (OMC-600) exhibits the most excellent electrochemical performance with the specific capacitance of 207.08 F/g obtained from cyclic voltammetry at the scan rate of 1 mV/s, small resistance and low self-discharge rate. Moreover, the supercapacitor based on the OMC-600 material exhibits good capacitance properties and stable cycle behavior with the specific capacitance of 105 F/g at the current density of 700 mA/g, and keeps a specific capacitance of 98 F/g after 20000 consecutive charge/discharge cycles.

  16. Mesoporous Silicon-Based Anodes for High Capacity, High Performance Li-ion Batteries, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — A new high capacity anode composite based on mesoporous silicon is proposed. By virtue of a structure that resembles a pseudo one-dimensional phase, the active anode...

  17. Noncompetitive and Competitive Adsorption of Heavy Metals in Sulfur-Functionalized Ordered Mesoporous Carbon.

    Science.gov (United States)

    Saha, Dipendu; Barakat, Soukaina; Van Bramer, Scott E; Nelson, Karl A; Hensley, Dale K; Chen, Jihua

    2016-12-14

    In this work, sulfur-functionalized ordered mesoporous carbons were synthesized by activating the soft-templated mesoporous carbons with sulfur bearing salts that simultaneously enhanced the surface area and introduced sulfur functionalities onto the parent carbon surface. XPS analysis showed that sulfur content within the mesoporous carbons were between 8.2% and 12.9%. The sulfur functionalities include C-S, C═S, -COS, and SO x . SEM images confirmed the ordered mesoporosity within the material. The BET surface areas of the sulfur-functionalized ordered mesoporous carbons range from 837 to 2865 m 2 /g with total pore volume of 0.71-2.3 cm 3 /g. The carbon with highest sulfur functionality was examined for aqueous phase adsorption of mercury (as HgCl 2 ), lead (as Pb(NO 3 ) 2 ), cadmium (as CdCl 2 ), and nickel (as NiCl 2 ) ions in both noncompetitive and competitive mode. Under noncompetitive mode and at a pH greater than 7.0 the affinity of sulfur-functionalized carbons toward heavy metals were in the order of Hg > Pb > Cd > Ni. At lower pH, the adsorbent switched its affinity between Pb and Cd. In the noncompetitive mode, Hg and Pb adsorption showed a strong pH dependency whereas Cd and Ni adsorption did not demonstrate a significant influence of pH. The distribution coefficient for noncompetitive adsorption was in the range of 2448-4000 mL/g for Hg, 290-1990 mL/g for Pb, 550-560 mL/g for Cd, and 115-147 for Ni. The kinetics of adsorption suggested a pseudo-second-order model fits better than other models for all the metals. XPS analysis of metal-adsorption carbons suggested that 7-8% of the adsorbed Hg was converted to HgSO 4 , 14% and 2% of Pb was converted to PbSO 4 and PbS/PbO, respectively, and 5% Cd was converted to CdSO 4 . Ni was below the detection limit for XPS. Overall results suggested these carbon materials might be useful for the separation of heavy metals.

  18. Application of a hybrid ordered mesoporous silica as sorbent for solid-phase multi-residue extraction of veterinary drugs in meat by ultra-high-performance liquid chromatography coupled to ion-trap tandem mass spectrometry.

    Science.gov (United States)

    Casado, Natalia; Morante-Zarcero, Sonia; Pérez-Quintanilla, Damián; Sierra, Isabel

    2016-08-12

    A quick, sensitive and selective analytical reversed-phase multi-residue method using ultra-high performance liquid chromatography coupled to an ion-trap mass spectrometry detector (UHPLC-IT-MS/MS) operating in both positive and negative ion mode was developed for the simultaneous determination of 23 veterinary drug residues (β-blockers, β-agonists and Non-Steroidal Anti-inflammatory Drugs (NSAIDs)) in meat samples. The sample treatment involved a liquid-solid extraction followed by a solid-phase extraction (SPE) procedure. SBA-15 type mesoporous silica was synthetized and modified with octadecylsilane, and the resulting hybrid material (denoted as SBA-15-C18) was applied and evaluated as SPE sorbent in the purification of samples. The materials were comprehensively characterized, and they showed a high surface area, high pore volume and a homogeneous distribution of the pores. Chromatographic conditions and extraction procedure were optimized, and the method was validated according to the Commission Decision 2002/657/EC. The method detection limits (MDLs) and the method quantification limits (MQLs) were determined for all the analytes in meat samples and found to range between 0.01-18.75μg/kg and 0.02-62.50μg/kg, respectively. Recoveries for 15 of the target analytes ranged from 71 to 98%. In addition, for comparative purpose SBA-15-C18 was evaluated towards commercial C18 amorphous silica. Results revealed that SBA-15-C18 was clearly more successful in the multi-residue extraction of the 23 mentioned analytes with higher recovery values. The method was successfully tested to analyze prepacked preparations of mince bovine meat. Traces of propranolol, ketoprofen and diclofenac were detected in some samples. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. MoO2-ordered mesoporous carbon nanocomposite as an anode material for lithium-ion batteries.

    Science.gov (United States)

    Zeng, Lingxing; Zheng, Cheng; Deng, Cuilin; Ding, Xiaokun; Wei, Mingdeng

    2013-03-01

    In the present work, the nanocomposite of MoO2-ordered mesoporous carbon (MoO2-OMC) was synthesized for the first time using a carbon thermal reduction route and the mesoporous carbon as the nanoreactor. The synthesized nanocomposite was characterized by X-ray diffraction (XRD), thermogravimetric analysis (TGA), N2 adsorption-desorption, scanning electron microscopy (SEM), and transmission electron microscopy (TEM) measurements. Furthermore, this nanocomposite was used as an anode material for Li-ion intercalation and exhibited large reversible capacity, high rate performance, and good cycling stability. For instance, a high reversible capacity of 689 mAh g(-1) can remain after 50 cycles at a current density of 50 mA g(-1). It is worth mentioning that the MoO2-OMC nanocomposite electrode can attain a high reversible capacity of 401 mAh g(-1) at a current density as high as 2 A g(-1). These results might be due to the intrinsic characteristics of nanocomposite, which offered a better accommodation of the strain and volume changes and a shorter path for Li-ion and electron transport, leading to the improved capacity and enhanced rate capability.

  20. Bioactive SrO-SiO2 glass with well-ordered mesopores: characterization, physiochemistry and biological properties.

    Science.gov (United States)

    Wu, Chengtie; Fan, Wei; Gelinsky, Michael; Xiao, Yin; Simon, Paul; Schulze, Renate; Doert, Thomas; Luo, Yongxiang; Cuniberti, Gianaurelio

    2011-04-01

    For a biomaterial to be considered suitable for bone repair it should ideally be both bioactive and have a capacity for controllable drug delivery; as such, mesoporous SiO(2) glass has been proposed as a new class of bone regeneration material by virtue of its high drug-loading ability and generally good biocompatibility. It does, however, have less than optimum bioactivity and controllable drug delivery properties. In this study, we incorporated strontium (Sr) into mesoporous SiO(2) in an effort to develop a bioactive mesoporous SrO-SiO(2) (Sr-Si) glass with the capacity to deliver Sr(2+) ions, as well as a drug, at a controlled rate, thereby producing a material better suited for bone repair. The effects of Sr(2+) on the structure, physiochemistry, drug delivery and biological properties of mesoporous Sr-Si glass were investigated. The prepared mesoporous Sr-Si glass was found to have an excellent release profile of bioactive Sr(2+) ions and dexamethasone, and the incorporation of Sr(2+) improved structural properties, such as mesopore size, pore volume and specific surface area, as well as rate of dissolution and protein adsorption. The mesoporous Sr-Si glass had no cytotoxic effects and its release of Sr(2+) and SiO(4)(4-) ions enhanced alkaline phosphatase activity - a marker of osteogenic cell differentiation - in human bone mesenchymal stem cells. Mesoporous Sr-Si glasses can be prepared to porous scaffolds which show a more sustained drug release. This study suggests that incorporating Sr(2+) into mesoporous SiO(2) glass produces a material with a more optimal drug delivery profile coupled with improved bioactivity, making it an excellent material for bone repair applications. Copyright © 2010 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  1. Crosslinked Enzyme Aggregates in Hierarchically-Ordered Mesoporous Silica: A Simple and Effective Method for Enzyme Stabilization

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Moon Il; Kim, Jungbae; Lee, Jinwoo; Jia, Hongfei; Na, Hyon Bin; Youn, Jongkyu; Kwak, Ja Hun; Dohnalkova, Alice; Grate, Jay W.; Wang, Ping; Hyeon, Taeghwan; Park, Hyun-Gyu; Chang, Ho Nam

    2007-02-01

    alpha-chymotrypsin (CT) and lipase (LP) were immobilized in hierarchically-ordered mesocellular mesoporous silica (HMMS) in a simple but effective way for the enzyme stabilization, which was achieved by the enzyme adsorption followed by glutaraldehyde (GA) crosslinking. This resulted in the formation of nanometer scale crosslinked enzyme aggregates (CLEAs) entrapped in the mesocellular pores of HMMS (37 nm), which did not leach out of HMMS through narrow mesoporous channels (13 nm). CLEA of alpha-chymotrypsin (CLEA-CT) in HMMS showed a high enzyme loading capacity and significantly increased enzyme stability. No activity decrease of CLEA-CT was observed for two weeks under even rigorously shaking condition, while adsorbed CT in HMMS and free CT showed a rapid inactivation due to the enzyme leaching and presumably autolysis, respectively. With the CLEA-CT in HMMS, however, there was no tryptic digestion observed suggesting that the CLEA-CT is not susceptible to autolysis. Moreover, CLEA of lipase (CLEA-LP) in HMMS retained 30% specific activity of free lipase with greatly enhanced stability. This work demonstrates that HMMS can be efficiently employed as host materials for enzyme immobilization leading to highly enhanced stability of the immobilized enzymes with high enzyme loading and activity.

  2. Enhanced microwave absorption properties of Ni-doped ordered mesoporous carbon/polyaniline nanocomposites

    International Nuclear Information System (INIS)

    Wang, Liuding; Wu, Hongjing; Shen, Zhongyuan; Guo, Shaoli; Wang, Yiming

    2012-01-01

    Highlights: ► OMC-Ni/PANI nanocomposites were prepared by in situ polymerization method. ► The effective absorption bandwidth was 4.7 GHz for OMC-Ni0.15/PANI. ► OMC-Ni/PANI showed excellent microwave absorption with respect to OMC-Ni. ► This effect could be mainly attributed to the improvement of impendence matching. - Abstract: We propose and demonstrate a new scheme to improve microwave absorption property through polyaniline (PANI)-functionalized Ni-doped ordered mesoporous carbon (OMC) by in situ polymerization method. The polymer-functionalized nanocomposites, embedding polyaniline within ordered mesoporous carbon, exhibit strong and broadband microwave absorption due to its better dielectric loss characteristic. OMC-Ni0.15/PANI exhibits an effective absorption bandwidth (i.e., reflection loss (RL) ≤ −10 dB) of 4.7 GHz and an absorption peak of −51 dB at 9.0 GHz. The absorption peak intensity and position can be tuned by controlling the thickness of the coating.

  3. Nitrogen-doped mesoporous carbons for high performance supercapacitors

    Science.gov (United States)

    Wu, Kai; Liu, Qiming

    2016-08-01

    The mesoporous carbons have been synthesized by using α-D(+)-Glucose, D-Glucosamine hydrochloride or their mixture as carbon precursors and mesoporous silicas (SBA-15 or MCF) as hard templates. The as-prepared products show a large pore volume (0.59-0.97 cm3 g-1), high surface areas (352.72-1152.67 m2 g-1) and rational nitrogen content (ca. 2.5-3.9 wt.%). The results of electrochemical tests demonstrate that both heteroatom doping and suitable pore structure play a decisive role in the performance of supercapacitors. The representative sample of SBA-15 replica obtained using D-Glucosamine hydrochloride only exhibits high specific capacitance (212.8 F g-1 at 0.5 A g-1) and good cycle durability (86.1% of the initial capacitance after 2000 cycles) in 6 M KOH aqueous electrolyte, which is attributed to the contribution of double layer capacitance and pseudo-capacitance. The excellent electrochemical performance makes it a promising electrode material for supercapacitors.

  4. Adsorption of CO₂, CH₄, and N₂ on ordered mesoporous carbon: approach for greenhouse gases capture and biogas upgrading.

    Science.gov (United States)

    Yuan, Bin; Wu, Xiaofei; Chen, Yingxi; Huang, Jianhan; Luo, Hongmei; Deng, Shuguang

    2013-05-21

    Separation of CO₂ and N₂ from CH₄ is significantly important in natural gas upgrading, and capture/removal of CO₂, CH₄ from air (N₂) is essential to greenhouse gas emission control. Adsorption equilibrium and kinetics of CO₂, CH₄, and N₂ on an ordered mesoporous carbon (OMC) sample were systematically investigated to evaluate its capability in the above two applications. The OMC was synthesized and characterized with TEM, TGA, small-angle XRD, and nitrogen adsorption/desorption measurements. Pure component adsorption isotherms of CO₂, CH₄, and N₂ were measured at 278, 298, and 318 K and pressures up to 100 kPa, and correlated with the Langmuir model. These data were used to estimate the separation selectivities for CO₂/CH₄, CH₄/N₂, and CO₂/N₂ binary mixtures at different compositions and pressures according to the ideal adsorbed solution theory (IAST) model. At 278 K and 100 kPa, the predicted selectivities for equimolar CO₂/CH₄, CH4/N₂, and CO₂/N₂ are 3.4, 3.7, and 12.8, respectively; and the adsorption capacities for CH₄ and CO₂ are 1.3 and 3.0 mmol/g, respectively. This is the first report of a versatile mesoporous material that displays both high selectivities and large adsorption capacities for separating CO₂/CH₄, CH₄/N₂, and CO₂/N₂ mixtures.

  5. Large third-order optical nonlinearity in vertically oriented mesoporous silica thin films embedded with Ag nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Tan, Min; Liu, Qiming, E-mail: qmliu@whu.edu.cn [Wuhan University, Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, School of Physics and Technology (China)

    2016-12-15

    Taking advantage of the channel confinement of mesoporous films to prevent the agglomeration of Ag nanoparticles to achieve large third-order optical nonlinearity in amorphous materials, Ag-loaded composite mesoporous silica film was prepared by the electrochemical deposition method on ITO substrate. Ag ions were firstly transported into the channels of mesoporous film by the diffusion and binding force of channels, which were reduced to nanoparticles by applying suitable voltage. The existence and uniform distribution of Ag nanoparticles ranging in 1–10 nm in the mesoporous silica thin films were exhibited by UV spectrophotometer, X-ray powder diffraction (XRD), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS) measurements. The third-order optical nonlinearity induced by Ag nanoparticles was studied by the Z-scan technique. Due to the local field surface plasmon resonance, the maximum third-order nonlinear optical susceptibility of Ag-loaded composite mesoporous silica film is 1.53×10{sup −10} esu, which is 1000 times larger than that of the Ag-contained chalcogenide glasses which showed large nonlinearity in amorphous materials.

  6. Adsorptive performance of chromium-containing ordered mesoporous silica on volatile organic compounds (VOCs

    Directory of Open Access Journals (Sweden)

    Jianwei Fan

    2017-09-01

    Full Text Available Volatile organic compounds (VOCs are the primary poisonous emissions into the atmosphere in natural gas exploitation and disposing process. The adsorption method has been widely applied in actual production because of its good features such as low cost, low energy consumption, flexible devices needed, etc. The commonly used adsorbents like activated carbon, silicon molecular sieves and so on are not only susceptible to plugging or spontaneous combustion but difficult to be recycled. In view of this, a new adsorbent (CrSBA15 was made by the co-assembly method to synthesize the ordered mesoporous silica materials with different amounts of chromium to eliminate VOCs. This new adsorbent was characterized by small-angle-X-ray scattering (SAXS, nitrogen adsorption/desorption, scanning electron microscopy (SEM, and transmission electron microscopy (TEM. Its adsorption performance to eliminate VOCs (toluene, benzene, cyclohexane and ethyl acetate used as typical pollutants was also tested systematically. Research results indicate that this new adsorbent of CrSBA-15(30, with the silicon/chromium ration being 30, owns the maximum micropore volume, and shows a higher adsorption performance in eliminating toluene, benzene, cyclohexane and ethyl acetate. Besides, it is cost-effective and much easier to be recycled than the activated carbon. In conclusion, CrSBA-15(30 is a good adsorbent to eliminate VOCs with broad application prospects. Keywords: Mesoporous materials, Silicon dioxide, Synthesis, Adsorption, Volatile organic compounds (VOCs, Recyclability, Energy saving

  7. Tuning the Pore Geometry of Ordered Mesoporous Carbons for Enhanced Adsorption of Bisphenol-A

    Directory of Open Access Journals (Sweden)

    Wannes Libbrecht

    2015-04-01

    Full Text Available Mesoporous carbons were synthesized via both soft and hard template methods and compared to a commercial powder activated carbon (PAC for the adsorption ability of bisphenol-A (BPA from an aqueous solution. The commercial PAC had a BET-surface of 1027 m2/g with fine pores of 3 nm and less. The hard templated carbon (CMK-3 material had an even higher BET-surface of 1420 m2/g with an average pore size of 4 nm. The soft templated carbon (SMC reached a BET-surface of 476 m2/g and a pore size of 7 nm. The maximum observed adsorption capacity (qmax of CMK-3 was the highest with 474 mg/g, compared to 290 mg/g for PAC and 154 mg/g for SMC. The difference in adsorption capacities was attributed to the specific surface area and hydrophobicity of the adsorbent. The microporous PAC showed the slowest adsorption, while the ordered mesopores of SMC and CMK-3 enhanced the BPA diffusion into the adsorbent. This difference in adsorption kinetics is caused by the increase in pore diameter. However, CMK-3 with an open geometry consisting of interlinked nanorods allows for even faster intraparticle diffusion.

  8. Tuning the Pore Geometry of Ordered Mesoporous Carbons for Enhanced Adsorption of Bisphenol-A

    Science.gov (United States)

    Libbrecht, Wannes; Vandaele, Koen; De Buysser, Klaartje; Verberckmoes, An; Thybaut, Joris W.; Poelman, Hilde; De Clercq, Jeriffa; Van Der Voort, Pascal

    2015-01-01

    Mesoporous carbons were synthesized via both soft and hard template methods and compared to a commercial powder activated carbon (PAC) for the adsorption ability of bisphenol-A (BPA) from an aqueous solution. The commercial PAC had a BET-surface of 1027 m2/g with fine pores of 3 nm and less. The hard templated carbon (CMK-3) material had an even higher BET-surface of 1420 m2/g with an average pore size of 4 nm. The soft templated carbon (SMC) reached a BET-surface of 476 m2/g and a pore size of 7 nm. The maximum observed adsorption capacity (qmax) of CMK-3 was the highest with 474 mg/g, compared to 290 mg/g for PAC and 154 mg/g for SMC. The difference in adsorption capacities was attributed to the specific surface area and hydrophobicity of the adsorbent. The microporous PAC showed the slowest adsorption, while the ordered mesopores of SMC and CMK-3 enhanced the BPA diffusion into the adsorbent. This difference in adsorption kinetics is caused by the increase in pore diameter. However, CMK-3 with an open geometry consisting of interlinked nanorods allows for even faster intraparticle diffusion. PMID:28788023

  9. Oriented Decoration in Metal-Functionalized Ordered Mesoporous Silicas and Their Catalytic Applications in the Oxidation of Aromatic Compounds

    Directory of Open Access Journals (Sweden)

    Shijian Zhou

    2018-02-01

    Full Text Available Ordered mesoporous silicas (OMSs attract considerable attention due to their advanced structural properties. However, for the pristine silica materials, the inert property greatly inhibits their catalytic applications. Thus, to contribute to the versatile surface of OMSs, different metal active sites, including acidic/basic sites and redox sites, have been introduced into specific locations (mesoporous channels and framework of OMSs and the metal-functionalized ordered mesoporous silicas (MOMSs show great potential in the catalytic applications. In this review, we first present the categories of metal active sites. Then, the synthesized processes of MOMSs are thoroughly discussed, in which the metal active sites would be introduced with the assistance of organic groups into the specific locations of OMSs. In addition, the structural morphologies of OMSs are elaborated and the catalytic applications of MOMSs in the oxidation of aromatic compounds are illustrated in detail. Finally, the prospects for the future development in this field are proposed.

  10. The effect of Co-doping on the humidity sensing properties of ordered mesoporous TiO2

    Science.gov (United States)

    Li, Zhong; Haidry, Azhar Ali; Gao, Bin; Wang, Tao; Yao, ZhengJun

    2017-08-01

    Monitoring of humidity is of utmost importance as it is essential part of almost every process in our life. Many commercial humidity sensors based on metal oxide semiconductors are available in the market, but there is still need to synthesize low-cost, fast and highly sensitive humidity sensors with no interference from background environment. The aim of this work was to fabricate the ordered mesoporous un-doped and Co-doped TiO2 (0.1-5 mol% Co) and to analyze its humidity sensing properties at room temperatures. The ordered mesoporous powders with high specific surface area (SSA) were prepared by multicomponent self-assembly procedure and then spray-coated onto the sensor substrates with interdigitated gold electrodes. The sensors exhibited excellent stability and reproducible resistance change under various relative humidity percentages (9-90% RH) with negligible effect of background environment. For instance, the response to 90% RH at room temperature was about five orders of magnitude (∼1.39 × 105) and the response time (Tres) was ∼24 s. The reaction/recovery times of the sensors were compared with commercial humidity sensor to show that the reaction times in this work are not given by the surface reaction of water vapor on the sensor surfaces, rather these are mainly influenced by the experimental setup. The sensor response increased up to 3 mol% Co-contents and then decreased for 5 mol% Co-contents. Based on the experimental results, the surface reaction of humidity is discussed related to specific surface area, average grain size and cobalt contents to understand the humidity sensing mechanism.

  11. Recovery of silica from electronic waste for the synthesis of cubic MCM-48 and its application in preparing ordered mesoporous carbon molecular sieves using a green approach

    Energy Technology Data Exchange (ETDEWEB)

    Liou, Tzong-Horng, E-mail: thliou@mail.mcut.edu.tw [Ming Chi University of Technology, Department of Chemical Engineering, Taiwan (China)

    2012-07-15

    The electronics industry is one of the world's fastest growing manufacturing industries. However, e-waste has become a serious pollution problem. This study reports the recovery of e-waste for preparing valuable MCM-48 and ordered mesoporous carbon for the first time. Specifically, this study adopts an alkali-extracted method to obtain sodium silicate precursors from electronic packaging resin ash. The influence of synthesis variables such as gelation pH, neutral/cationic surfactant ratio, hydrothermal treatment temperature, and calcination temperature on the mesophase of MCM-48 materials is investigated. Experimental results confirm that well-ordered cubic MCM-48 materials were synthesized in strongly acidic and strongly basic media. The resulting mesoporous silica had a high surface area of 1,317 m{sup 2}/g, mean pore size of about 3.0 nm, and a high purity of 99.87 wt%. Ordered mesoporous carbon with high surface area (1,715 m{sup 2}/g) and uniform pore size of CMK-1 type was successfully prepared by impregnating MCM-48 template using the resin waste. The carbon structure was sensitive to the sulfuric acid concentration and carbonization temperature. Converting e-waste into MCM-48 materials not only eliminates the disposal problem of e-waste, but also transforms industrial waste into a useful nanomaterial.

  12. Template-mediated, Hierarchical Engineering of Ordered Mesoporous Films and Powders

    Science.gov (United States)

    Tian, Zheng

    techniques to various substrates for low-cost counter-electrodes in dye-sensitized solar cells, as we demonstrate, or as potential high-flux membranes for molecular separations. Inspired by 'one-pot' 'soft'-templating approaches, wherein the pore forming agent and replica precursor are co-assembled, we establish how 'hard'-templating can be carried out in an analogous fashion. Namely, we show how pre-formed silica nanoparticles can be co-assembled from aqueous solutions with a carbon source (glucose), leading to elucidation of a pseudo-phase behavior in which we identify an operating window for synthesis of hierarchically bi-continuous carbon films. Systematic study of the association of carbon precursors with the silica particles in combination with transient coating experiments reveals mechanistic insight into how silica-adsorbed carbon precursor modulates particle assembly and ultimately controls template particle d-spacing. We uncover a critical d-spacing defining the boundary between ordered and disordered mesoporosity within the resulting films. We ultimately extend this thin-film mechanistic insight to realize 'one'-pot, bi-continuous 3DOm carbon powders. Through a combination of X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and high-resolution transmission electron microscopy (HR-TEM), we elucidate novel synthesis-structure relations for template-mediated microstructuring of the 3DOm replica carbons. Attractive properties of the resulting bi-continuous porous carbons for applications, for example, as novel electrodes, include high surface areas, large mesopore volumes, and tunable graphitic content (i.e. >50%) and character. We specifically demonstrate their performance, in thin film form, as counter-electrodes in dye-sensitized solar cells. We also demonstrate how they can be exploited in powder form as high-performance supercapacitor electrodes exhibiting attractive retention and absolute capacitance. We conclude the thesis by demonstrating the

  13. Fine-tuning the Wall Thickness of Ordered Mesoporous Graphene by Exploiting Ligand Exchange of Colloidal Nanocrystals

    Science.gov (United States)

    Han, Dandan; Yan, Yancui; Wei, Jishi; Wang, Biwei; Li, Tongtao; Guo, Guannan; Yang, Dong; Xie, Songhai; Dong, Angang

    2017-12-01

    Because of their unique physical properties, three-dimensional (3D) graphene has attracted enormous attention over the past years. However, it is still a challenge to precisely control the layer thickness of 3D graphene. Here, we report a novel strategy to rationally adjust the wall thickness of ordered mesoporous graphene (OMG). By taking advantage of ligand exchange capability of colloidal Fe3O4 nanocrystals, we are able to fine-tune the wall thickness of OMG from 2 to 6 layers of graphene by tailoring the hydrocarbon ligands attached to the nanocrystal surface. When evaluated as electrocatalyst for oxygen reduction reaction upon S and N doping, the 4-layer OMG is found to show better catalytic performance compared with its 2- and 6-layer counterparts, which we attribute to the enhanced exposure of active sites resulting from its ultrathin wall thickness and high surface area.

  14. Fine-Tuning the Wall Thickness of Ordered Mesoporous Graphene by Exploiting Ligand Exchange of Colloidal Nanocrystals

    Directory of Open Access Journals (Sweden)

    Dandan Han

    2017-12-01

    Full Text Available Because of their unique physical properties, three-dimensional (3D graphene has attracted enormous attention over the past years. However, it is still a challenge to precisely control the layer thickness of 3D graphene. Here, we report a novel strategy to rationally adjust the wall thickness of ordered mesoporous graphene (OMG. By taking advantage of ligand exchange capability of colloidal Fe3O4 nanocrystals, we are able to fine-tune the wall thickness of OMG from 2 to 6 layers of graphene. When evaluated as electrocatalyst for oxygen reduction reaction upon S and N doping, the 4-layer OMG is found to show better catalytic performance compared with their 2- and 6-layer counterparts, which we attribute to the enhanced exposure of active sites arising from the thin wall thickness and high surface area.

  15. Comparative study on the electrocatalytic activities of ordered mesoporous carbons and graphene

    International Nuclear Information System (INIS)

    Wang Huan; Qi Bin; Lu Baoping; Bo Xiangjie; Guo Liping

    2011-01-01

    In this work, a comparative study on the electrocatalytic activities of ordered mesoporous carbons (OMCs) and graphene (GR) is presented. Using voltammetry and amperometry as detection methods, four DNA bases, double-stranded DNA (dsDNA), six important electroactive compounds and various biomolecules were employed to investigate their electrochemical responses on OMC and GR modified glassy carbon electrodes (OMC/GCE and GR/GCE). The results show that OMC/GCE enhances the electron transfer kinetics of these compounds compared to GR/GCE. The discrepancy in electrochemical activities can be attributed to the different microstructures of OMC and GR, which were examined by transmission electron microscopy, X-ray photoelectron spectra, X-ray diffraction, Raman spectra and nitrogen adsorption-desorption.

  16. A novel method to prepare binary Ni-Fe compounds and ordered mesoporous carbon composite as a supercapacitor electrode

    Energy Technology Data Exchange (ETDEWEB)

    Feng, J.; Tang, B.; Zhao, J.; Liu, P.; Xu, J. [Shanghai Univ. of Engineering Science (China). College of Chemistry and Chemical Engineering

    2010-07-01

    Superapacitor electrodes with nickel/iron compounds and ordered mesoporous carbon (OMC) nanocomposites were fabricated using a incipient wetness impregnation and hydrothermal methods. The use of the nickel-iron compounds within the OMC framework resulted in a synergistic effect. Resistance was also improved. Transmission electron microscopy (TEM) and X-ray diffraction (XRD) analyses demonstrated that the host structure was preserved during the impregnation and hydrothermal procedures. Nano-sized metal compounds were formed within the mesopore system. Nitrogen adsorption and desorption isotherm measurements demonstrated mesoporosity for the host/guest composites.

  17. Facile Fabrication of Composition-Tuned Ru-Ni Bimetallics in Ordered Mesoporous Carbon for Levulinic Acid Hydrogenation

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Ying; Gao, Guang; Zhang, Xin; Li, Fuwei [ChinaU - Petroleum; (Chinese Aca. Sci.)

    2016-02-04

    Bimetallic catalysts are of great importance due to their unique catalytic properties. However, their conventional synthesis requires tedious multistep procedures and prolonged synthetic time, and the resulting bimetallics usually disperse unevenly and show poor stability. It is challenging to develop a facile and step-economic synthetic methodology for highly efficient bimetallic catalysts. In this study, we report an elegant metal complex-involved multicomponent assembly route to highly efficient Ru–Ni bimetallics in ordered mesoporous carbons (OMC). The fabrication of composition-tuned Ru–Ni bimetallics in OMC (RuxNi1–x–OMC, x = 0.5–0.9) was facilely realized via in situ construction of CTAB-directed cubic Ia3d chitosan-ruthenium–nickel–silica mesophase before pyrolysis and silica removal. The resulting RuxNi1–x–OMC materials are in-depth characterized with X-ray diffraction, N2 adsorption–desorption, transmission electron microscopy, infrared spectrum, and X-ray absorption fine structure. This facile fabrication method renders homogeneously dispersed Ru–Ni bimetallics embedded in the mesoporous carbonaceous framework and creates a highly active and stable Ru0.9Ni0.1–OMC catalyst for the hydrogenation of levulinic acid (LA) to prepare γ-valerolactone (GVL), a biomass-derived platform molecule with wide application in the preparation of renewable chemicals and liquid transportation fuels. A high TOF (>2000 h–1) was obtained, and the Ru0.9Ni0.1–OMC catalyst could be used at least 15 times without obvious loss of its catalytic performance.

  18. Catalytic Activity of Cobalt Grafted on Ordered Mesoporous Silica Materials in N2O Decomposition and CO Oxidation.

    Czech Academy of Sciences Publication Activity Database

    Kuboňová, L.; Peikertová, P.; Mamulová Kutláková, K.; Jirátová, Květa; Słowik, G.; Obalová, L.; Cool, P.

    2017-01-01

    Roč. 437, AUG 2017 (2017), s. 57-72 ISSN 2468-8231 R&D Projects: GA ČR GA14-13750S Institutional support: RVO:67985858 Keywords : mesoporous ordered silica * cobalt * N2O decomposition Subject RIV: CI - Industrial Chemistry, Chemical Engineering OBOR OECD: Chemical process engineering

  19. 有序介孔炭的研究进展%Research development of ordered mesoporous carbon

    Institute of Scientific and Technical Information of China (English)

    刘攀博; 焦剑; 黄英

    2012-01-01

    综述了以硬模板法、软模板法和混合模板法合成有序介孔炭的研究进展.对上述三种制备有序介孔炭的方法和原理进行了的简单介绍,指出各种方法在制备有序介孔炭时存在的长处与不足.讨论了采用不同模板剂和炭前躯体对所制备的有序介孔炭的结构、孔径大小、孔径分布及物理化学性能的影响,指出在制备有序介孔炭的过程中,主要问题是选择一种与模板剂可产生较强相互作用的炭前躯体并控制炭前躯体与模板之间的摩尔比率.最后对有序介孔炭的潜在应用和发展方向进行了展望.%The research development of ordered mesoporous carbon synthesized by hard template method, soft template method and mixed template method was summarized. The above three synthesis methods and principles of ordered mesoporous carbon were introdued briefly, and the advantages and disadvantages of each method were also pointed out. Structure, pore size, pore size distribution and physical and chemical properties of ordered mesoporous carbon synthesized by different template types and carbon precursors were discussed. The main problems in the preparation of ordered mesoporous carbon are choosing a suitable carbon precursor which can strongly interact with template and controlling the molar ratio between the carbon precursor and template. Finally, the potential applications and developing direction of ordered mesoporous carbon were prospected.

  20. Equilibrium, kinetic and thermodynamic studies for adsorption of BTEX onto Ordered Mesoporous Carbon (OMC).

    Science.gov (United States)

    Konggidinata, Mas Iwan; Chao, Bing; Lian, Qiyu; Subramaniam, Ramalingam; Zappi, Mark; Gang, Daniel Dianchen

    2017-08-15

    Chemical and petrochemical industries produce substantial amounts of wastewater everyday. This wastewater contains organic pollutants such as benzene, toluene, ethylbenzene and xylenes (BTEX) that are toxic to human and aquatic life. Ordered Mesoporous Carbon (OMC), the adsorbent that possesses the characteristics of an ideal adsorbent was investigated to understand its properties and suitability for BTEX removal. Adsorption isotherms, adsorption kinetics, the effects of initial BTEX concentrations and temperatures on the adsorption process were studied. The OMCs were characterized using surface area and pore size analyzer, transmission electron microscopy (TEM), elemental analysis, thermogravimetric analysis (TGA) and fourier transform infrared spectroscopy (FTIR). The results suggested that the Langmuir Isotherm and Pseudo-Second-Order Models described the experimental data well. The thermodynamic parameters, Gibbs free energy (ΔG°), the enthalpy change (ΔH°) and the entropy change (ΔS°) of adsorption indicated that the adsorption processes were physical, endothermic, and spontaneous. In addition, OMC had 27% higher overall adsorption capacities compared to granular activated carbon (GAC). Copyright © 2017 Elsevier B.V. All rights reserved.

  1. A general chelate-assisted co-assembly to metallic nanoparticles-incorporated ordered mesoporous carbon catalysts for Fischer-Tropsch synthesis.

    Science.gov (United States)

    Sun, Zhenkun; Sun, Bo; Qiao, Minghua; Wei, Jing; Yue, Qin; Wang, Chun; Deng, Yonghui; Kaliaguine, Serge; Zhao, Dongyuan

    2012-10-24

    The organization of different nano objects with tunable sizes, morphologies, and functions into integrated nanostructures is critical to the development of novel nanosystems that display high performances in sensing, catalysis, and so on. Herein, using acetylacetone as a chelating agent, phenolic resol as a carbon source, metal nitrates as metal sources, and amphiphilic copolymers as a template, we demonstrate a chelate-assisted multicomponent coassembly method to synthesize ordered mesoporous carbon with uniform metal-containing nanoparticles. The obtained nanocomposites have a 2-D hexagonally arranged pore structure, uniform pore size (~4.0 nm), high surface area (~500 m(2)/g), moderate pore volume (~0.30 cm(3)/g), uniform and highly dispersed Fe(2)O(3) nanoparticles, and constant Fe(2)O(3) contents around 10 wt %. By adjusting acetylacetone amount, the size of Fe(2)O(3) nanoparticles is readily tunable from 8.3 to 22.1 nm. More importantly, it is found that the metal-containing nanoparticles are partially embedded in the carbon framework with the remaining part exposed in the mesopore channels. This unique semiexposure structure not only provides an excellent confinement effect and exposed surface for catalysis but also helps to tightly trap the nanoparticles and prevent aggregating during catalysis. Fischer-Tropsch synthesis results show that as the size of iron nanoparticles decreases, the mesoporous Fe-carbon nanocomposites exhibit significantly improved catalytic performances with C(5+) selectivity up to 68%, much better than any reported promoter-free Fe-based catalysts due to the unique semiexposure morphology of metal-containing nanoparticles confined in the mesoporous carbon matrix.

  2. Mesoporous Three-Dimensional Graphene Networks for Highly Efficient Solar Desalination under 1 sun Illumination.

    Science.gov (United States)

    Kim, Kwanghyun; Yu, Sunyoung; An, Cheolwon; Kim, Sung-Wook; Jang, Ji-Hyun

    2018-05-09

    Solar desalination via thermal evaporation of seawater is one of the most promising technologies for addressing the serious problem of global water scarcity because it does not require additional supporting energy other than infinite solar energy for generating clean water. However, low efficiency and a large amount of heat loss are considered critical limitations of solar desalination technology. The combination of mesoporous three-dimensional graphene networks (3DGNs) with a high solar absorption property and water-transporting wood pieces with a thermal insulation property has exhibited greatly enhanced solar-to-vapor conversion efficiency. 3DGN deposited on a wood piece provides an outstanding value of solar-to-vapor conversion efficiency, about 91.8%, under 1 sun illumination and excellent desalination efficiency of 5 orders salinity decrement. The mass-producible 3DGN enriched with many mesopores efficiently releases the vapors from an enormous area of the surface by heat localization on the top surface of the wood piece. Because the efficient solar desalination device made by 3DGN on the wood piece is highly scalable and inexpensive, it could serve as one of the main sources for the worldwide supply of purified water achieved via earth-abundant materials without an extra supporting energy source.

  3. Synthesis, characterization, and application of surface-functionalized ordered mesoporous nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Po-Wen [Iowa State Univ., Ames, IA (United States)

    2009-01-01

    The dissertation begins with Chapter 1, which is a general introduction of the fundamental synthesis of mesoporous silica materials, the selective functionlization of mesoporous silica materials, and the synthesis of nanostructured porous materials via nanocasting. In Chapter 2, the thermo-responsive polymer coated mesoporous silica nanoparticles (MSN) was synthesized via surface-initated polymerization and exhibited unique partition activities in a biphasic solution with the thermally induced change. In Chapter 3, the monodispersed spherical MSN with different mesoporous structure (MCM-48) was developed and employed as a template for the synthesis of mesoporous carbon nanoparticles (MCN) via nanocasting. MCN was demonstrated for the delivery of membrane impermeable chemical agents inside the cells. The cellular uptake efficiency and biocompabtibility of MCN with human cervical cancer cells were also investigated. In addition to the biocompabtibility of MCN, MCN was demonstrated to support Rh-Mn nanoparticles for catalytic reaction in Chapter 4. Owing to the unique mesoporosity, Rh-Mn nanoparticles can be well distributed inside the mesoporous structure and exhibited interesting catalytic performance on CO hydrogenation. In Chapter 5, the synthesis route of the aforementioned MCM-48 MSN was discussed and investigated in details and other metal oxide nanoparticles were also developed via nanocasting by using MCM-48 MSN as a template. At last, there is a general conclusion summarized in Chapter 6.

  4. Physical properties of ordered mesoporous SBA-15 silica as immunological adjuvant

    Science.gov (United States)

    Mariano-Neto, F.; Matos, J. R.; Cides da Silva, L. C.; Carvalho, L. V.; Scaramuzzi, K.; Sant'Anna, O. A.; Oliveira, C. P.; Fantini, M. C. A.

    2014-10-01

    This work reports a detailed analysis of the ordered mesoporous SBA-15 silica synthesis procedure that provides a matrix with mean pore diameter around 10 nm. The encapsulation of bovine serum albumin (BSA) by four different methods allowed the determination of the best imbibition condition, which is keeping the mixture under rest and solvent evaporation. Simulation of the in situ SAXS scattered intensity of the BSA release in potassium buffer solution, gastrointestinal fluids revealed a slow evolution of BSA content, independent of the media. Proton induced x-ray emission results obtained in calcined mouse organs revealed that silica is only present in the spleen after 35 days and is completely eliminated from all mouse organs after 10 weeks. Biological studies showed that Santa Barbara Amorphous-15 is an effective adjuvant when compared to the traditional Al(OH)3, and is non-toxic to mice, rats, dogs and even cells, such as macrophages and dendritic cells. Recent studies showed that the immunological response is improved by enhancing the inflammatory response and the recruitment of immune competent cells to the site of injection as by the oral route and, most importantly, by increasing the number of phagocytes of a particulate antigen by antigen presenting cells. This research is under the scope of the International Patent WO 07030901, IN248654,ZA2008/02277, KR 1089400, MX297263, JP5091863, CN101287491B.

  5. Polyaniline-Derived Ordered Mesoporous Carbon as an Efficient Electrocatalyst for Oxygen Reduction Reaction

    Directory of Open Access Journals (Sweden)

    Kai Wan

    2015-06-01

    Full Text Available Nitrogen-doped ordered mesoporous carbon was synthesized by using polyaniline as the carbon source and SBA-15 as the template. The microstructure, composition and electrochemical behavior were extensively investigated by the nitrogen sorption isotherm, X-ray photoelectron spectroscopy, cyclic voltammetry and rotating ring-disk electrode. It is found that the pyrolysis temperature yielded a considerable effect on the pore structure, elemental composition and chemical configuration. The pyrolysis temperature from 800 to 1100 °C yielded a volcano-shape relationship with both the specific surface area and the content of the nitrogen-activated carbon. Electrochemical tests showed that the electrocatalytic activity followed a similar volcano-shape relationship, and the carbon catalyst synthesized at 1000 °C yielded the best performance. The post-treatment in NH3 was found to further increase the specific surface area and to enhance the nitrogen doping, especially the edge-type nitrogen, which favored the oxygen reduction reaction in both acid and alkaline media. The above findings shed light on electrocatalysis and offer more strategies for the controllable synthesis of the doped carbon catalyst.

  6. Efficient MgO-based mesoporous CO2 trapper and its performance at high temperature.

    Science.gov (United States)

    Han, Kun Kun; Zhou, Yu; Chun, Yuan; Zhu, Jian Hua

    2012-02-15

    A novel MgO-based porous adsorbent has been synthesized in a facile co-precipitation method for the first time, in order to provide a candidate for trapping CO(2) in flue gas at high temperature. The resulting composite exhibits a mesoporous structure with a wide pore size distribution, due to the even dispersion and distribution of microcrystalline MgO in the framework of alumina to form a concrete-like structure. These sorbents can capture CO(2) at high temperature (150-400°C), possessing high reactivity and stability in cyclic adsorption-desorption processes, providing competitive candidates to control CO(2) emission. Copyright © 2011 Elsevier B.V. All rights reserved.

  7. Synthesis of non-siliceous mesoporous oxides.

    Science.gov (United States)

    Gu, Dong; Schüth, Ferdi

    2014-01-07

    Mesoporous non-siliceous oxides have attracted great interest due to their unique properties and potential applications. Since the discovery of mesoporous silicates in 1990s, organic-inorganic assembly processes by using surfactants or block copolymers as soft templates have been considered as a feasible path for creating mesopores in metal oxides. However, the harsh sol-gel conditions and low thermal stabilities have limited the expansion of this method to various metal oxide species. Nanocasting, using ordered mesoporous silica or carbon as a hard template, has provided possibilities for preparing novel mesoporous materials with new structures, compositions and high thermal stabilities. This review concerns the synthesis, composition, and parameter control of mesoporous non-siliceous oxides. Four synthesis routes, i.e. soft-templating (surfactants or block copolymers as templates), hard-templating (mesoporous silicas or carbons as sacrificial templates), colloidal crystal templating (3-D ordered colloidal particles as a template), and super lattice routes, are summarized in this review. Mesoporous metal oxides with different compositions have different properties. Non-siliceous mesoporous oxides are comprehensively described, including a discussion of constituting elements, synthesis, and structures. General aspects concerning pore size control, atomic scale crystallinity, and phase control are also reviewed.

  8. Simple fabrication of solid phase microextraction fiber employing nitrogen-doped ordered mesoporous polymer by in situ polymerization.

    Science.gov (United States)

    Zheng, Juan; Liang, Yeru; Liu, Shuqin; Jiang, Ruifen; Zhu, Fang; Wu, Dingcai; Ouyang, Gangfeng

    2016-01-04

    A combination of nitrogen-doped ordered mesoporous polymer (NOMP) and stainless steel wires led to highly sensitive, selective, and stable solid phase microextraction (SPME) fibers by in situ polymerization for the first time. The ordered structure of synthesized NOMP coating was illustrated by transmission electron microscopy (TEM) and X-ray diffraction (XRD), and microscopy analysis by scanning electron microscopy (SEM) confirmed a homogenous morphology of the NOMP-coated fiber. The NOMP-coated fiber was further applied for the extraction of organochlorine pesticides (OCPs) with direct-immersion solid-phase microextraction (DI-SPME) method followed by gas chromatography-mass spectrometry (GC-MS) quantification. Under the optimized conditions, low detection limits (0.023-0.77 ng L(-1)), a wide linear range (9-1500 ng L(-1)), good repeatability (3.5-8.1%, n=6) and excellent reproducibility (1.5-8.3%, n=3) were achieved. Moreover, the practical feasibility of the proposed method was evaluated by determining OCPs in environmental water samples with satisfactory recoveries. Copyright © 2015 Elsevier B.V. All rights reserved.

  9. High-performance gas sensing achieved by mesoporous tungsten oxide mesocrystals with increased oxygen vacancies

    KAUST Repository

    Wang, Dong

    2013-01-01

    The inner structure of W18O49 mesocrystals was observed by electron microscopy with the help of ultramicrotomy and focused ion beam techniques. The results showed that these mesocrystals contain irregular mesopores formed through partial fusion of self-assembled nanowires, and consequently have long-range structural ordering in one dimension and short-range ordering in the other two dimensions. The W18O 49 mesocrystals exhibit superior performance in gas sensing applications, which is considered to be associated with the presence of more oxygen vacancy sites in the unique mesoporous structure. © 2013 The Royal Society of Chemistry.

  10. Ordered molecular arrays as templates: A new approach to synthesis of mesoporous materials

    Science.gov (United States)

    Behrens, P.; Stucky, G.

    There has been a growing interest in the extension of the microporous molecular sieve synthesis and applications to mesoscopic dimensions. Typical areas for the application of mesoscopic zeolite-type structures are in separation (e.g., protein separation and selective adsorption of large organic molecules from waste waters) and catalysis (e.g., processing of tar sand and of the high distillates of crude oils to valuable low-boiling products). Another is in the supramolecular assembly of molecular array and polymers for electronic and optical applications. In a new concept in the synthesis of porous material the templating agent is no longer a single, solvated, organic molecule or metal ion, but rather a self-assembled molecular array. This template leads to mesoporous materials with adjustable pore sizes between 16 and greater than 100 Angstrom, covering well the mesophorous range of greatest interest. The periodic arrangement of pores is very regular, and the pore size distribution measured by absorption is nearly as sharp as that of conventional zeolites.

  11. Hierarchical micro- and mesoporous carbide-derived carbon as a high-performance electrode material in supercapacitors.

    Science.gov (United States)

    Rose, Marcus; Korenblit, Yair; Kockrick, Emanuel; Borchardt, Lars; Oschatz, Martin; Kaskel, Stefan; Yushin, Gleb

    2011-04-18

    Ordered mesoporous carbide-derived carbon (OM-CDC) materials produced by nanocasting of ordered mesoporous silica templates are characterized by a bimodal pore size distribution with a high ratio of micropores. The micropores result in outstanding adsorption capacities and the well-defined mesopores facilitate enhanced kinetics in adsorption processes. Here, for the first time, a systematic study is presented, in which the effects of synthesis temperature on the electrochemical performance of these materials in supercapacitors based on a 1 M aqueous solution of sulfuric acid and 1-ethyl-3-methylimidazolium tetrafluoroborate ionic liquid are reported. Cyclic voltammetry shows the specific capacitance of the OM-CDC materials exceeds 200 F g(-1) in the aqueous electrolyte and 185 F g(-1) in the ionic liquid, when measured in a symmetric configuration in voltage ranges of up to 0.6 and 2 V, respectively. The ordered mesoporous channels in the produced OM-CDC materials serve as ion-highways and allow for very fast ionic transport into the bulk of the OM-CDC particles. At room temperature the enhanced ion transport leads to 75% and 90% of the capacitance retention at current densities in excess of ∼10 A g(-1) in ionic liquid and aqueous electrolytes, respectively. The supercapacitors based on 250-300 μm OM-CDC electrodes demonstrate an operating frequency of up to 7 Hz in aqueous electrolyte. The combination of high specific capacitance and outstanding rate capabilities of the OM-CDC materials is unmatched by state-of-the art activated carbons and strictly microporous CDC materials. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Effects of ordered mesoporous structure and La-doping on the microwave absorbing properties of CoFe2O4

    Science.gov (United States)

    Shang, Tao; Lu, Qingshan; Chao, Luomeng; Qin, Yanli; Yun, Yuehou; Yun, Guohong

    2018-03-01

    Low-density ordered mesoporous CoFe2O4 (Osbnd CFO) and CoLa0.12Fe1.88O4 (Osbnd CLFO) are prepared by nanocasting method using mesoporous silica SBA-15 as a hard-template. The crystal structure, surface chemical state, magnetic properties and electromagnetic parameters are characterized by X-ray diffraction, transmission electron microscopy, N2 adsorption-desorption measurement, X-ray photoelectron spectroscopy, physical property measurement system and vector network analyzer. The results show that all the samples formed a single phase with cubic spinel structure. Meanwhile Osbnd CFO and Osbnd CLFO possess a highly ordered mesostructure. Comparing with particle CoFe2O4 (P-CFO), Osbnd CFO with high specific surface area exhibits lower magnetic saturation (Ms), higher imaginary part of complex permittivity (ε‧‧) and imaginary part of the complex permeability (μ‧‧). The minimum reflection loss (RL) of Osbnd CFO reaches -27.36 dB with a matching thickness of 3.0 mm. The enhancement of the microwave absorbing performances of Osbnd CFO can be mainly attributed to the good impedance matching, high electromagnetic wave attenuation and multiple reflections of electromagnetic wave originated from the ordered mesoporous structure. The Ms of Osbnd CLFO decreases after La3+ doping, while the specific surface area, coercivity value, ε‧‧ and μ‧‧ of Osbnd CLFO increase. The minimum RL of Osbnd CLFO reaches -46.47 dB with a thickness of 3.0 mm, and the effective absorption frequency bandwidth reaches 4.9 GHz.

  13. A facile one-pot self-assembly approach to incorporate SnOx nanoparticles in ordered mesoporous carbon with soft templating for fuel cells

    Science.gov (United States)

    Huang, Yingqiang; Zhai, Zhicheng; Luo, Zhigang; Liu, Yingju; Liang, Zhurong; Fang, Yueping

    2014-04-01

    Unique SnOx (x = 1,2)/ordered mesoporous carbon nanocomposites (denoted as SnOx/OMC) are firstly synthesized through a ‘one-pot’ synthesis together with the soft template self-assembly approach. The obtained SnOx/OMC nanocomposites with various SnOx contents exhibit uniform pore sizes between 3.9 and 4.2 nm, high specific surface areas between 497 and 595 m2 g-1, and high pore volumes between 0.39 and 0.48 cm3 g-1. With loading of Pt, Pt-SnOx/OMC with relatively low SnOx content exhibits superior electrocatalytic performance, long-term durability, and resistance to CO poisoning for methanol oxidation, as compared to Pt/OMC, PtRu/C and Pt-SnOx/C, which may be attributed not only to the synergetic effect of embedded SnOx, but also to the highly ordered mesostructure with high specific surface areas and large pore volumes affording plenty of surface area for support of Pt nanoparticles. This work supplies an efficient way to synthesize novel ordered mesoporous carbon self-supported metallic oxide as catalyst support and its further potential application to reduce the cost of catalysts in direct methanol fuel cells.

  14. A facile one-pot self-assembly approach to incorporate SnOx nanoparticles in ordered mesoporous carbon with soft templating for fuel cells

    International Nuclear Information System (INIS)

    Huang, Yingqiang; Zhai, Zhicheng; Luo, Zhigang; Liu, Yingju; Liang, Zhurong; Fang, Yueping

    2014-01-01

    Unique SnO x  (x = 1,2)/ordered mesoporous carbon nanocomposites (denoted as SnO x /OMC) are firstly synthesized through a ‘one-pot’ synthesis together with the soft template self-assembly approach. The obtained SnO x /OMC nanocomposites with various SnO x contents exhibit uniform pore sizes between 3.9 and 4.2 nm, high specific surface areas between 497 and 595 m 2  g −1 , and high pore volumes between 0.39 and 0.48 cm 3  g −1 . With loading of Pt, Pt–SnO x /OMC with relatively low SnO x content exhibits superior electrocatalytic performance, long-term durability, and resistance to CO poisoning for methanol oxidation, as compared to Pt/OMC, PtRu/C and Pt–SnO x /C, which may be attributed not only to the synergetic effect of embedded SnO x , but also to the highly ordered mesostructure with high specific surface areas and large pore volumes affording plenty of surface area for support of Pt nanoparticles. This work supplies an efficient way to synthesize novel ordered mesoporous carbon self-supported metallic oxide as catalyst support and its further potential application to reduce the cost of catalysts in direct methanol fuel cells. (paper)

  15. Thermo-sensitively and magnetically ordered mesoporous carbon nanospheres for targeted controlled drug release and hyperthermia application.

    Science.gov (United States)

    Chen, Lin; Zhang, Huan; Zheng, Jing; Yu, Shiping; Du, Jinglei; Yang, Yongzhen; Liu, Xuguang

    2018-03-01

    A multifunctional nanoplatform based on thermo-sensitively and magnetically ordered mesoporous carbon nanospheres (TMOMCNs) is developed for effective targeted controlled release of doxorubicin hydrochloride (DOX) and hyperthermia in this work. The morphology, specific surface area, porosity, thermo-stability, thermo-sensitivity, as well as magnetism properties of TMOMCNs were verified by high resolution transmission electron microscopy, field emission scanning electron microscopy, thermo-gravimetric analysis, X-ray diffraction, Brunauer-Emmeltt-Teller surface area analysis, dynamic light scattering and vibrating sample magnetometry measurement. The results indicate that TMOMCNs have an average diameter of ~146nm with a lower critical solution temperature at around 39.5°C. They are superparamagnetic with a magnetization of 10.15emu/g at 20kOe. They generate heat when inductive magnetic field is applied to them and have a normalized specific absorption rate of 30.23W/g at 230kHz and 290Oe, showing good potential for hyperthermia. The DOX loading and release results illustrate that the loading capacity is 135.10mg/g and release performance could be regulated by changing pH and temperature. The good targeting, DOX loading and release and hyperthermia properties of TMOMCNs offer new probabilities for high effectiveness and low toxicity of cancer chemotherapy. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Facile synthesis of highly stable and well-dispersed mesoporous ZrO(2)/carbon composites with high performance in oxidative dehydrogenation of ethylbenzene.

    Science.gov (United States)

    Li, Qiang; Xu, Jie; Wu, Zhangxiong; Feng, Dan; Yang, Jianping; Wei, Jing; Wu, Qingling; Tu, Bo; Cao, Yong; Zhao, Dongyuan

    2010-09-28

    Highly ordered mesoporous ZrO(2)/carbon (FDU-15) composites have been synthesized via a facile evaporation induced triconstituent co-assembly (EISA) approach by using Pluronic F127 as a template and zirconium oxychloride octahydrate and resol as Zr and carbon sources. The synthesized mesoporous composites exhibit a highly ordered two-dimensional (2-D) hexagonal mesostructure with relatively high specific surface areas (up to 947 m(2) g(-1)), pore sizes around 3.8 nm and high pore volumes (up to 0.71 cm(3) g(-1)). The results clearly show that the crystalline zirconia nanoparticles (ca. 1.9-3.9 nm) are well-dispersed in amorphous matrices of the ordered mesoporous carbon FDU-15 materials, which construct the nanocomposites. The ordered mesostructures of the obtained ZrO(2)/FDU-15 composites can be well-retained even at the high pyrolysis temperature (up to 900 degrees C), suggesting a high thermal stability. The zirconia content of the ZrO(2)/FDU-15 composites can be tunable in a wide range (up to 47%). Moreover, the resultant mesoporous ZrO(2)/FDU-15 composites exhibit high catalytic activity in oxidative dehydrogenation (ODH) of ethylbenzene (EB) to styrene (ST), with high ethylbenzene conversion (59.6%) and styrene selectivity (90.4%), which is mainly attributed to the synergistic catalytic effect between the oxygen-containing groups located on the carbon pore walls and weakly basic sites of the nanocrystalline ZrO(2). Furthermore, the high specific surface areas and opening pore channels are also responsible for their high catalytic activity. Therefore, it is a very promising catalyst material in styrene production on an industrial scale.

  17. Controlling morphology, mesoporosity, crystallinity, and photocatalytic activity of ordered mesoporous TiO{sub 2} films prepared at low temperature

    Energy Technology Data Exchange (ETDEWEB)

    Elgh, Björn; Yuan, Ning; Palmqvist, Anders E. C. [Applied Surface Chemistry, Department of Chemical and Biological Engineering, Chalmers University of Technology, SE 412 96 Göteborg (Sweden); Cho, Hae Sung; Terasaki, Osamu [Graduate School of EEWS (WCU), KAIST, Daejeon 305-701 (Korea, Republic of); Magerl, David; Philipp, Martine; Müller-Buschbaum, Peter [Lehrstuhl für Funktionelle Materialien, Physik-Department, Technische Universität München, 85748 Garching (Germany); Roth, Stephan V. [DESY, Notkestrasse 85, 22603 Hamburg (Germany); Yoon, Kyung Byung [Department of Chemistry, Sogang University, Seoul 121-742 (Korea, Republic of)

    2014-11-01

    Partly ordered mesoporous titania films with anatase crystallites incorporated into the pore walls were prepared at low temperature by spin-coating a microemulsion-based reaction solution. The effect of relative humidity employed during aging of the prepared films was studied using SEM, TEM, and grazing incidence small angle X-ray scattering to evaluate the mesoscopic order, porosity, and crystallinity of the films. The study shows unambiguously that crystal growth occurs mainly during storage of the films and proceeds at room temperature largely depending on relative humidity. Porosity, pore size, mesoscopic order, crystallinity, and photocatalytic activity of the films increased with relative humidity up to an optimum around 75%.

  18. Mesoporous aluminum phosphite

    International Nuclear Information System (INIS)

    El Haskouri, Jamal; Perez-Cabero, Monica; Guillem, Carmen; Latorre, Julio; Beltran, Aurelio; Beltran, Daniel; Amoros, Pedro

    2009-01-01

    High surface area pure mesoporous aluminum-phosphorus oxide-based derivatives have been synthesized through an S + I - surfactant-assisted cooperative mechanism by means of a one-pot preparative procedure from aqueous solution and starting from aluminum atrane complexes and phosphoric and/or phosphorous acids. A soft chemical extraction procedure allows opening the pore system of the parent as-prepared materials by exchanging the surfactant without mesostructure collapse. The nature of the pore wall can be modulated from mesoporous aluminum phosphate (ALPO) up to total incorporation of phosphite entities (mesoporous aluminum phosphite), which results in a gradual evolution of the acidic properties of the final materials. While phosphate groups in ALPO act as network building blocks (bridging Al atoms), the phosphite entities become basically attached to the pore surface, what gives practically empty channels. The mesoporous nature of the final materials is confirmed by X-ray diffraction (XRD), transmission electron microscopy (TEM) and N 2 adsorption-desorption isotherms. The materials present regular unimodal pore systems whose order decreases as the phosphite content increases. NMR spectroscopic results confirm the incorporation of oxo-phosphorus entities to the framework of these materials and also provide us useful information concerning the mechanism through which they are formed. - Abstract: TEM image of the mesoporous aluminum phosphite showing the hexagonal disordered pore array that is generated by using surfactant micelles as template. Also a scheme emphasizing the presence of an alumina-rich core and an ALPO-like pore surface is presented.

  19. Highly Efficient Method for the Synthesis of Activated Mesoporous Biocarbons with Extremely High Surface Area for High-Pressure CO2 Adsorption.

    Science.gov (United States)

    Singh, Gurwinder; Lakhi, Kripal S; Kim, In Young; Kim, Sungho; Srivastava, Prashant; Naidu, Ravi; Vinu, Ajayan

    2017-09-06

    A simple and efficient way to synthesize activated mesoporous biocarbons (AMBs) with extremely high BET surface area and large pore volume has been achieved for the first time through a simple solid state activation of freely available biomass, Arundo donax, with zinc chloride. The textural parameters of the AMB can easily be controlled by varying the activation temperature. It is demonstrated that the mesoporosity of AMB can be finely tuned with a simple adjustment of the amount of activating agent. AMB with almost 100% mesoporosity can be achieved using the activating agent and the biomass ratio of 5 and carbonization at 500 °C. Under the optimized conditions, AMB with a BET surface area of 3298 m 2 g -1 and a pore volume of 1.9 cm 3 g -1 can be prepared. While being used as an adsorbent for CO 2 capture, AMB registers an impressively high pressure CO 2 adsorption capacity of 30.2 mmol g -1 at 30 bar which is much higher than that of activated carbon (AC), multiwalled carbon nanotubes (MWCNTs), highly ordered mesoporous carbons, and mesoporous carbon nitrides. AMB also shows high stability with excellent regeneration properties under vacuum and temperatures of up to 250 °C. These impressive textural parameters and high CO 2 adsorption capacity of AMB clearly reveal its potential as a promising adsorbent for high-pressure CO 2 capture and storage application. Also, the simple one-step synthesis strategy outlined in this work would provide a pathway to generate a series of novel mesoporous activated biocarbons from different biomasses.

  20. Morphology, microstructure, and magnetic properties of ordered large-pore mesoporous cadmium ferrite thin film spin glasses.

    Science.gov (United States)

    Reitz, Christian; Suchomski, Christian; Chakravadhanula, Venkata Sai Kiran; Djerdj, Igor; Jagličić, Zvonko; Brezesinski, Torsten

    2013-04-01

    Herein, we report the synthesis, microstructure, and magnetic properties of cadmium ferrite (CdFe2O4) thin films with both an ordered cubic network of 18 nm diameter pores and single-phase spinel grains averaging 13 nm in diameter. These mesoporous materials were produced through facile polymer templating of hydrated nitrate salt precursors. Both the morphology and the microstructure, including cation site occupancy and electronic bonding configuration, were analyzed in detail by electron microscopy, grazing incidence small-angle X-ray scattering, Raman and X-ray photoelectron spectroscopy, and N2-physisorption. The obtained data demonstrate that the network of pores is retained up to annealing temperatures as high as 650 °C--the onset of crystallization is at ϑ = (590 ± 10) °C. Furthermore, they show that the polymer-templated samples exhibit a "partially" inverted spinel structure with inversion parameter λ = 0.40 ± 0.02. This differs from microcrystalline CdFe2O4 which shows virtually no inversion. Magnetic susceptibility studies reveal ferrimagnetic spin coupling below 147 K and further point to the likelihood of glassy behavior at low temperature (T(f) ≈ 60 K). In addition, analysis of room temperature magnetization data indicates the presence of sub-10 nm diameter superparamagnetic clusters in an otherwise paramagnetic environment.

  1. Controlled synthesis of ordered mesoporous TiO{sub 2}-supported on activated carbon and pore-pore synergistic photocatalytic performance

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Chen; Li, Youji, E-mail: bcclyj@163.com; Xu, Peng; Li, Ming; Zeng, Mengxiong

    2015-01-15

    Ordered mesoporous titania/activated carbon (OMTAC) were prepared by the template technique with the aid of an ultrasonic method. To explore the relationship between the structure and properties of OMTAC, the ultrasonic-sol-gel technique was applied to synthesize titania dioxide/activated carbon (USTAC). The obtained material structure was characterized by X-ray diffraction (XRD), nitrogen adsorption – desorption, transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), UV diffuse reflectance (DRS) and Photoluminescence (PL) emission spectra. OMTAC photocatalytic performance was evaluated by means of acid red B (ARB) degradation. The pore-pore synergistic amplification mechanism of photocatalysis was proposed and the effects of catalytic conditions on synergistic amplification were explored. The results show that compared to OMT, OMTAC has a small particle size, low electron-hole recombination rate and high surface areas, due to the hindering effect of activated carbon on crystalline grain growth and an ordered mesoporous structure of titania. OMTAC has higher catalytic activity than USTAC, OMT and P25, due to pore-pore synergistic amplification effect of photocatalysis. The OMT content is strongly affected OMTAC photocatalytic activity, and OMTAC-3 (loading 3 times of OMT on AC) has the highest photocatalytic activity due to high hydroxyl concentration, surface area and low electron-hole recombination rate. When ARB is degraded by OMTAC-3, the optimum catalytic conditions are a catalyst concentration of 1 g/L, an ARB concentration of 15 mg/L and a pH of 5. - Graphical abstract: We investigate the influence of mesoporous titania content upon the photocatalytic performance of OMTAC in acid red B degradation. - Highlights: • OMTAC were fabricated by a template technique with the aid of an ultrasonic method. • OMTAC show high photoactivity for acid red B (ARB) degradation. • OMTAC also show pore-pore synergistic photocatalytic

  2. Amine-modified ordered mesoporous silica: Effect of pore size on carbon dioxide capture

    Czech Academy of Sciences Publication Activity Database

    Zeleňák, V.; Badaničová, M.; Halamová, D.; Čejka, Jiří; Zukal, Arnošt; Murafa, Nataliya; Goerigk, G.

    2008-01-01

    Roč. 144, č. 2 (2008), s. 336-342 ISSN 1385-8947 R&D Projects: GA ČR GA203/08/0604 Institutional research plan: CEZ:AV0Z40400503; CEZ:AV0Z40320502 Keywords : mesoporous silica * hexagonal * amine * carbon dioxide Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.813, year: 2008

  3. Cellular membrane trafficking of mesoporous silica nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Fang, I-Ju [Iowa State Univ., Ames, IA (United States)

    2012-01-01

    This dissertation mainly focuses on the investigation of the cellular membrane trafficking of mesoporous silica nanoparticles. We are interested in the study of endocytosis and exocytosis behaviors of mesoporous silica nanoparticles with desired surface functionality. The relationship between mesoporous silica nanoparticles and membrane trafficking of cells, either cancerous cells or normal cells was examined. Since mesoporous silica nanoparticles were applied in many drug delivery cases, the endocytotic efficiency of mesoporous silica nanoparticles needs to be investigated in more details in order to design the cellular drug delivery system in the controlled way. It is well known that cells can engulf some molecules outside of the cells through a receptor-ligand associated endocytosis. We are interested to determine if those biomolecules binding to cell surface receptors can be utilized on mesoporous silica nanoparticle materials to improve the uptake efficiency or govern the mechanism of endocytosis of mesoporous silica nanoparticles. Arginine-glycine-aspartate (RGD) is a small peptide recognized by cell integrin receptors and it was reported that avidin internalization was highly promoted by tumor lectin. Both RGD and avidin were linked to the surface of mesoporous silica nanoparticle materials to investigate the effect of receptor-associated biomolecule on cellular endocytosis efficiency. The effect of ligand types, ligand conformation and ligand density were discussed in Chapter 2 and 3. Furthermore, the exocytosis of mesoporous silica nanoparticles is very attractive for biological applications. The cellular protein sequestration study of mesoporous silica nanoparticles was examined for further information of the intracellular pathway of endocytosed mesoporous silica nanoparticle materials. The surface functionality of mesoporous silica nanoparticle materials demonstrated selectivity among the materials and cancer and normal cell lines. We aimed to determine

  4. High efficiency nanocomposite sorbents for CO2 capture based on amine-functionalized mesoporous capsules

    KAUST Repository

    Qi, Genggeng; Wang, Yanbing; Estevez, Luis; Duan, Xiaonan; Anako, Nkechi; Park, Ah-Hyung Alissa; Li, Wen; Jones, Christopher W.; Giannelis, Emmanuel P.

    2011-01-01

    A novel high efficiency nanocomposite sorbent for CO2 capture has been developed based on oligomeric amine (polyethylenimine, PEI, and tetraethylenepentamine, TEPA) functionalized mesoporous silica capsules. The newly synthesized sorbents exhibit extraordinary capture capacity up to 7.9 mmol g-1 under simulated flue gas conditions (pre-humidified 10% CO 2). The CO2 capture kinetics were found to be fast and reached 90% of the total capacities within the first few minutes. The effects of the mesoporous capsule features such as particle size and shell thickness on CO2 capture capacity were investigated. Larger particle size, higher interior void volume and thinner mesoporous shell thickness all improved the CO2 capacity of the sorbents. PEI impregnated sorbents showed good reversibility and stability during cyclic adsorption-regeneration tests (50 cycles). © 2011 The Royal Society of Chemistry.

  5. Synthesis and high catalytic properties of mesoporous Pt nanowire array by novel conjunct template method

    Science.gov (United States)

    Zhong, Yi; Xu, Cai-Ling; Kong, Ling-Bin; Li, Hu-Lin

    2008-12-01

    A novel conjunct template method for fabricating mesoporous Pt nanowire array through direct current (DC) electrodeposition of Pt into the pores of anodic aluminum oxide (AAO) template on Ti/Si substrate from hexagonal structured lyotropic liquid crystalline phase is demonstrated in this paper. The morphology and structure of as-prepared Pt nanowire array are characterized by field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). The electrocatalytic properties of Pt nanowire array for methanol are also investigated in detail. The results indicate that Pt nanowire array has the unique mesoporous structure of approximate 40-50 nm in diameter, which resulted in the high surface area and greatly improved electrocatalytic activity for methanol. The mesoporous Pt nanowire array synthesized by the new conjunct template method has a very promising application in portable fuel cell power sources.

  6. Amine-modified ordered mesoporous silica: Effect of pore size on carbon dioxide capture

    Energy Technology Data Exchange (ETDEWEB)

    V. Zelenak; M. Badanicova; D. Halamova; J. Cejka; A. Zukal; N. Murafa; G. Goerigk [P.J. Safarik University, Kosice (Slovak Republic)

    2008-10-15

    Three mesoporous silica materials with different pore sizes and pore connectivity were prepared and functionalized with aminopropyl (AP) ligands by post-synthesis treatment. The materials were characterized by small angle X-ray scattering (SAXS), transmission electron microscopy (TEM), thermogravimetric analysis (TGA) and nitrogen adsorption/desorption experiments. The carbon dioxide sorption on modified mesoporous molecular sieves was investigated by using of microbalances at 25{sup o}C, and the influence of pore size and pore architecture on CO{sub 2} sorption was discussed. The large pore silica, SBA-15, showed the largest carbon dioxide sorption capacity (1.5 mmol/g), relating to highest amine surface density in this material. On the other hand, three-dimensional accessibility of amine sites inside the pores of SBA-12 silica resulted in a faster response to CO{sub 2} uptake in comparison with MCM-41 and SBA-15 molecular sieves

  7. Nitrogen-enriched carbon with extremely high mesoporosity and tunable mesopore size for high-performance supercapacitors

    Science.gov (United States)

    Yang, Xiaoqing; Li, Chengfei; Fu, Ruowen

    2016-07-01

    As one of the most potential electrode materials for supercapacitors, nitrogen-enriched nanocarbons are still facing challenge of constructing developed mesoporosity for rapid mass transportation and tailoring their pore size for performance optimization and expanding their application scopes. Herein we develop a series of nitrogen-enriched mesoporous carbon (NMC) with extremely high mesoporosity and tunable mesopore size by a two-step method using silica gel as template. In our approach, mesopore size can be easily tailored from 4.7 to 35 nm by increasing the HF/TEOS volume ratio from 1/100 to 1/4. The NMC with mesopores of 6.2 nm presents the largest mesopore volume, surface area and mesopore ratio of 2.56 cm3 g-1, 1003 m2 g-1 and 97.7%, respectively. As a result, the highest specific capacitance of 325 F g-1 can be obtained at the current density of 0.1 A g-1, which can stay over 88% (286 F g-1) as the current density increases by 100 times (10 A g-1). This approach may open the doors for preparation of nitrogen-enriched nanocarbons with desired nanostructure for numerous applications.

  8. Synthesis of high-quality mesoporous silicon particles for enhanced lithium storage performance

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Chundong, E-mail: apcdwang@hust.edu.cn [School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074 (China); Center of Super-Diamond and Advanced Films (COSDAF), Department of Physics and Materials Science, City University of Hong Kong, Kowloon, Hong Kong SAR (China); Ren, Jianguo [Center of Super-Diamond and Advanced Films (COSDAF), Department of Physics and Materials Science, City University of Hong Kong, Kowloon, Hong Kong SAR (China); Chen, Hao [Department of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou (China); Zhang, Yi [School of Chemical Engineering and Pharmacy, Wuhan Institute of Technology, Wuhan, 430073 (China); Ostrikov, Kostya [School of Chemistry, Physics, and Mechanical Engineering, Queensland University of Technology, Brisbane 4000, QLD (Australia); Manufacturing Flagship, CSIRO, P. O. Box 218, Lindfield, NSW 2070 (Australia); Zhang, Wenjun [Center of Super-Diamond and Advanced Films (COSDAF), Department of Physics and Materials Science, City University of Hong Kong, Kowloon, Hong Kong SAR (China); Li, Yi, E-mail: liyi@suda.edu.cn [Department of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou (China); Center of Super-Diamond and Advanced Films (COSDAF), Department of Physics and Materials Science, City University of Hong Kong, Kowloon, Hong Kong SAR (China)

    2016-04-15

    Silicon has been considered as one of the most promising anode materials for high-capacity lithium-ion batteries (LIBs) due to its ultrahigh theoretical capacity, abundance, and environmentally benign nature. Nonetheless, the severe break during the prolonged cycling results in poor electrochemical performance, which hinders its practical application. Herein, we report the synthesis of novel mesoporous silicon particles with a facile template method by using a magnesiothermic reduction for LIBs. The obtained silicon nanoparticles are highly porous with densely porous cavities (20–40 nm) on the wall, of which it presents good crystallization. Electrochemical measurements showed that the mesoporous silicon nanoparticles delivered a high reversible specific capacity of 910 mA h g{sup −1} at a high current density of 1200 mA g{sup −1} over 50 cycles. The specific capacity at such high current density is still over twofold than that of commercial graphite anode, suggesting that the nanoporous Si architectures is suitable for high-performance Si-based anodes for lithium ion batteries in terms of capacity, cycle life, and rate capacity. - Highlights: • Silica nanotubes were prepared with a facile template method. • Novel mesoporous silicon particles were obtained by magnesiothermic reduction. • High-Performance LIBs were achieved by using mesoporous Si particle Electrodes.

  9. Au and AuCu Nanoparticles Supported on SBA-15 Ordered Mesoporous Titania-Silica as Catalysts for Methylene Blue Photodegradation

    Directory of Open Access Journals (Sweden)

    Isabel Barroso-Martín

    2018-05-01

    Full Text Available The photocatalytic degradation of methylene blue (MB dye has been performed under UV irradiation in aqueous suspension, employing photocatalysts based on Au (1.5 wt % and AuCu (Au/Cu = 1, 2.0 wt %, and supported on SBA-15-ordered mesoporous silica, with and without titania (Si/Ti = 3, in order to evaluate the versatility of this mesoporous support in this type of reaction of great impact from the environmental point of view. Samples were characterized by X-ray diffraction (XRD, transmission electron microscopy (TEM, N2 adsorption-desorption at −196 °C, and X-ray photoelectron spectroscopy (XPS, so as to study their structural, optical, and chemical properties. All the prepared catalysts were found to be active in the test reaction. The bimetallic AuCu-based catalysts attained very high MB degradation values, in particular AuCu/SBA-15 titania-silica sample reached 100% of dye oxidation after the monitored reaction period (120 min.

  10. Highly effective catalytic peroxymonosulfate activation on N-doped mesoporous carbon for o-phenylphenol degradation.

    Science.gov (United States)

    Hou, Jifei; Yang, Shasha; Wan, Haiqin; Fu, Heyun; Qu, Xiaolei; Xu, Zhaoyi; Zheng, Shourong

    2018-04-01

    As a broad-spectrum preservative, toxic o-phenylphenol (OPP) was frequently detected in aquatic environments. In this study, N-doped mesoporous carbon was prepared by a hard template method using different nitrogen precursors and carbonization temperatures (i.e., 700, 850 and 1000 °C), and was used to activate peroxymonosulfate (PMS) for OPP degradation. For comparison, mesoporous carbon (CMK-3) was also prepared. Characterization results showed that the N-doped mesoporous carbon samples prepared under different conditions were perfect replica of their template. In comparison with ethylenediamine (EDA) and dicyandiamide (DCDA) as the precursors, N-doped mesoporous carbon prepared using EDA and carbon tetrachloride as the precursors displayed a higher catalytic activity for OPP degradation. Increasing carbonization temperature of N-doped mesoporous carbon led to decreased N content and increased graphitic N content at the expense of pyridinic and pyrrolic N. Electron paramagnetic resonance (EPR) analysis showed that PMS activation on N-doped mesoporous carbon resulted in highly active species and singlet oxygen, and catalytic PMS activation for OPP degradation followed a combined radical and nonradical reaction mechanism. Increasing PMS concentration enhanced OPP degradation, while OPP degradation rate was independent on initial OPP concentration. Furthermore, the dependency of OPP degradation on PMS concentration followed the Langmuir-Hinshelwood model, reflecting that the activation of adsorbed PMS was the rate controlling step. Based on the analysis by time-of-flight mass spectrometry, the degradation pathway of OPP was proposed. Copyright © 2018 Elsevier Ltd. All rights reserved.

  11. Fluid adsorption in ordered mesoporous solids determined by in situ small-angle X-ray scattering.

    Science.gov (United States)

    Findenegg, Gerhard H; Jähnert, Susanne; Müter, Dirk; Prass, Johannes; Paris, Oskar

    2010-07-14

    The adsorption of two organic fluids (n-pentane and perfluoropentane) in a periodic mesoporous silica material (SBA-15) is investigated by in situ small-angle X-ray scattering (SAXS) using synchrotron radiation. Structural changes are monitored as the ordered and disordered pores in the silica matrix are gradually filled with the fluids. The experiments yield integrated peak intensities from up to ten Bragg reflections from the 2D hexagonal pore lattice, and additionally diffuse scattering contributions arising from disordered (mostly intrawall) porosity. The analysis of the scattering data is based on a separation of these two contributions. Bragg scattering is described by adopting a form factor model for ordered pores of cylindrical symmetry which accounts for the filling of the microporous corona, the formation of a fluid film at the pore walls, and condensation of the fluid in the core. The filling fraction of the disordered intrawall pores is extracted from the diffuse scattering intensity and its dependence on the fluid pressure is analyzed on the basis of a three-phase model. The data analysis introduced here provides an important generalisation of a formalism presented recently (J. Phys. Chem. C, 2009, 13, 15201), which was applicable to contrast-matching fluids only. In this way, the adsorption behaviour of fluids into ordered and disordered pores in periodic mesoporous materials can be analyzed quantitatively irrespective of the fluid density.

  12. Highly active Pd-In/mesoporous alumina catalyst for nitrate reduction.

    Science.gov (United States)

    Gao, Zhenwei; Zhang, Yonggang; Li, Deyi; Werth, Charles J; Zhang, Yalei; Zhou, Xuefei

    2015-04-09

    The catalytic reduction of nitrate is a promising technology for groundwater purification because it transforms nitrate into nitrogen and water. Recent studies have mainly focused on new catalysts with higher activities for the reduction of nitrate. Consequently, metal nanoparticles supported on mesoporous metal oxides have become a major research direction. However, the complex surface chemistry and porous structures of mesoporous metal oxides lead to a non-uniform distribution of metal nanoparticles, thereby resulting in a low catalytic efficiency. In this paper, a method for synthesizing the sustainable nitrate reduction catalyst Pd-In/Al2O3 with a dimensional structure is introduced. The TEM results indicated that Pd and In nanoparticles could efficiently disperse into the mesopores of the alumina. At room temperature in CO2-buffered water and under continuous H2 as the electron donor, the synthesized material (4.9 wt% Pd) was the most active at a Pd-In ratio of 4, with a first-order rate constant (k(obs) = 0.241 L min(-1) g(cata)(-1)) that was 1.3× higher than that of conventional Pd-In/Al2O3 (5 wt% Pd; 0.19 L min(-1) g(cata)(-1)). The Pd-In/mesoporous alumina is a promising catalyst for improving the catalytic reduction of nitrate. Copyright © 2015 Elsevier B.V. All rights reserved.

  13. Co{sub 3}O{sub 4} nanoparticles embedded in ordered mesoporous carbon with enhanced performance as an anode material for Li-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Park, Junsu; Kim, Gil-Pyo [Seoul National University (SNU), World Class University (WCU) Program of Chemical Convergence for Energy and Environment C2E2, School of Chemical and Biological Engineering, College of Engineering, Institute of Chemical Processes (Korea, Republic of); Umh, Ha Nee [Kwangwoon University, Department of Chemical Engineering (Korea, Republic of); Nam, Inho; Park, Soomin [Seoul National University (SNU), World Class University (WCU) Program of Chemical Convergence for Energy and Environment C2E2, School of Chemical and Biological Engineering, College of Engineering, Institute of Chemical Processes (Korea, Republic of); Kim, Younghun [Kwangwoon University, Department of Chemical Engineering (Korea, Republic of); Yi, Jongheop, E-mail: jyi@snu.ac.kr [Seoul National University (SNU), World Class University (WCU) Program of Chemical Convergence for Energy and Environment C2E2, School of Chemical and Biological Engineering, College of Engineering, Institute of Chemical Processes (Korea, Republic of)

    2013-09-15

    A Co{sub 3}O{sub 4}/ordered mesoporous carbon (OMC) nanocomposite, in which Co{sub 3}O{sub 4} nanoparticles (NPs), with an average size of about 10 nm homogeneously embedded in the OMC framework, are prepared for use as an anode material in Li-ion batteries. The composite is prepared by a one-pot synthesis based on the solvent evaporation-induced co-self-assembly of a phenolic resol, a triblock copolymer F127, and Co(NO{sub 3}){sub 2}{center_dot}6H{sub 2}O, followed by carbonization and oxidation. The resulting material has a high reversible capacity of {approx}1,025 mA h g{sup -1} after 100 cycles at a current density of 0.1 A g{sup -1}. The enhanced cycling stability and rate capability of the composite can be attributed to the combined mesoporous nanostructure which provides efficient pathways for Li-ion transport and the homogeneous distribution of the Co{sub 3}O{sub 4} NPs in the pore wall of the OMC, which prevents aggregation. These findings suggest that the OMC has promise for use as a carbon metric for metals and metal oxides as an anode material in high performance Li-ion batteries.

  14. Scalable 2D Mesoporous Silicon Nanosheets for High-Performance Lithium-Ion Battery Anode.

    Science.gov (United States)

    Chen, Song; Chen, Zhuo; Xu, Xingyan; Cao, Chuanbao; Xia, Min; Luo, Yunjun

    2018-03-01

    Constructing unique mesoporous 2D Si nanostructures to shorten the lithium-ion diffusion pathway, facilitate interfacial charge transfer, and enlarge the electrode-electrolyte interface offers exciting opportunities in future high-performance lithium-ion batteries. However, simultaneous realization of 2D and mesoporous structures for Si material is quite difficult due to its non-van der Waals structure. Here, the coexistence of both mesoporous and 2D ultrathin nanosheets in the Si anodes and considerably high surface area (381.6 m 2 g -1 ) are successfully achieved by a scalable and cost-efficient method. After being encapsulated with the homogeneous carbon layer, the Si/C nanocomposite anodes achieve outstanding reversible capacity, high cycle stability, and excellent rate capability. In particular, the reversible capacity reaches 1072.2 mA h g -1 at 4 A g -1 even after 500 cycles. The obvious enhancements can be attributed to the synergistic effect between the unique 2D mesoporous nanostructure and carbon capsulation. Furthermore, full-cell evaluations indicate that the unique Si/C nanostructures have a great potential in the next-generation lithium-ion battery. These findings not only greatly improve the electrochemical performances of Si anode, but also shine some light on designing the unique nanomaterials for various energy devices. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Highly active Pd–In/mesoporous alumina catalyst for nitrate reduction

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Zhenwei; Zhang, Yonggang; Li, Deyi [State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Shanghai 200092 (China); Werth, Charles J. [Civil, Architectural and Environmental Engineering, University of Texas at Austin, 301 East Dean Keeton St., Stop C1786, Austin, TX 78712 (United States); Zhang, Yalei, E-mail: zhangyalei2003@163.com [State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Shanghai 200092 (China); Zhou, Xuefei, E-mail: zhouxuefei@tongji.edu.cn [State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Shanghai 200092 (China)

    2015-04-09

    Highlights: • Pd–In nanoparticles (6–7 nm) uniformly form in the mesopores of alumina (4 nm). • Pd–In nanoparticles aggregation is prevented during the synthesis process. • The reduction rate of nitrate is efficient by using the obtained catalyst. • The selectivity toward N{sub 2} is ideal by using the obtained catalyst. - Abstract: The catalytic reduction of nitrate is a promising technology for groundwater purification because it transforms nitrate into nitrogen and water. Recent studies have mainly focused on new catalysts with higher activities for the reduction of nitrate. Consequently, metal nanoparticles supported on mesoporous metal oxides have become a major research direction. However, the complex surface chemistry and porous structures of mesoporous metal oxides lead to a non-uniform distribution of metal nanoparticles, thereby resulting in a low catalytic efficiency. In this paper, a method for synthesizing the sustainable nitrate reduction catalyst Pd–In/Al{sub 2}O{sub 3} with a dimensional structure is introduced. The TEM results indicated that Pd and In nanoparticles could efficiently disperse into the mesopores of the alumina. At room temperature in CO{sub 2}-buffered water and under continuous H{sub 2} as the electron donor, the synthesized material (4.9 wt% Pd) was the most active at a Pd–In ratio of 4, with a first-order rate constant (k{sub obs} = 0.241 L min{sup −1} g{sub cata}{sup −1}) that was 1.3× higher than that of conventional Pd–In/Al{sub 2}O{sub 3} (5 wt% Pd; 0.19 L min{sup −1} g{sub cata}{sup −1}). The Pd–In/mesoporous alumina is a promising catalyst for improving the catalytic reduction of nitrate.

  16. Highly selective epoxidation of styrene over mesoporous Au-Ti-SBA-15 via photocatalysis process: Synthesis, characterization, and catalytic application

    Energy Technology Data Exchange (ETDEWEB)

    Guo Yajie; Liu Zhengwang [School of Chemistry and Materials Science, Huaibei Normal University, Huaibei 235000, Anhui (China); Wang Guangjian, E-mail: wgj2260@chnu.edu.cn [School of Chemistry and Materials Science, Huaibei Normal University, Huaibei 235000, Anhui (China); Huang Yanhog; Kang Fangfang [School of Chemistry and Materials Science, Huaibei Normal University, Huaibei 235000, Anhui (China)

    2011-11-15

    Highly ordered Au-Ti-SBA-15 mesoporous molecular sieves were successfully synthesized by one-pot hydrothermal synthesis in acid medium, and were characterized by XRD, UV-vis, SEM, element-mapping, HRTEM, N{sub 2} adsorption, XPS, {sup 29}Si MAS NMR, NH{sub 3}-TPD and FT-IR. The as-prepared Au-Ti-SBA-15 samples were possessed of highly ordered mesostructures with larger pore diameter, pore volume and uniform mesopore size distribution. In the oxidation of styrene with H{sub 2}O{sub 2} as the oxidant over Au-Ti-SBA-15 catalyst under photo-irradiation, reaction parameters, such as molar ratio of H{sub 2}O{sub 2} to styrene, reaction time, solvent, the amount of catalyst, catalyst species, and the amount of 3% NaOH, were conditioned at length. As a result, highly selective epoxidation of styrene over catalyst was carried out perfectly for 10 min with high TOF of 4.75 Multiplication-Sign 10{sup 3} min{sup -1}.

  17. Nitrogen Doped Ordered Mesoporous Carbon as Support of PtRu Nanoparticles for Methanol Electro-Oxidation

    Directory of Open Access Journals (Sweden)

    David Sebastián

    2018-04-01

    Full Text Available The low oxidation kinetics of alcohols and the need for expensive platinum group metals are still some of the main drawbacks for the commercialization of energy efficient direct alcohol fuel cells. In this work, we investigate the influence of nitrogen doping of ordered mesoporous carbon (CMK as support on the electrochemical activity of PtRu nanoparticles. Nitrogen doping procedures involve the utilization of pyrrole as both nitrogen and carbon precursor by means of a templating method using mesoporous silica. This method allows obtaining carbon supports with up to 14 wt. % nitrogen, with an effective introduction of pyridinic, pyrrolic and quaternary nitrogen. PtRu nanoparticles were deposited by sodium formate reduction method. The presence of nitrogen mainly influences the Pt:Ru atomic ratio at the near surface, passing from 50:50 on the bare (un-doped CMK to 70:30 for the N-doped CMK catalyst. The electroactivity towards the methanol oxidation reaction (MOR was evaluated in acid and alkaline electrolytes. The presence of nitrogen in the support favors a faster oxidation of methanol due to the enrichment of Pt at the near surface together with an increase of the intrinsic activity of PtRu nanoparticles.

  18. Amperometric catechol biosensor based on laccase immobilized on nitrogen-doped ordered mesoporous carbon (N-OMC)/PVA matrix

    International Nuclear Information System (INIS)

    Guo, Meiqing; Wang, Hefeng; Huang, Di; Han, Zhijun; Wang, Xiaojun; Li, Qiang; Chen, Jing

    2014-01-01

    A functionalized nitrogen-containing ordered mesoporous carbon (N-OMC), which shows good electrical properties, was synthesized by the carbonization of polyaniline inside a SBA-15 mesoporous silica template. Based on this, through entrapping laccase onto the N-OMC/polyvinyl alcohol (PVA) film a facilely fabricated amperometric biosensor was developed. Laccase from Trametes versicolor was assembled on a composite film of a N-OMC/PVA modified Au electrode and the electrochemical behavior was investigated. The results indicated that the N-OMC modified electrode exhibits electrical properties towards catechol. The optimum experimental conditions of a biosensor for the detection of catechol were studied in detail. Under the optimal conditions, the sensitivity of the biosensor was 0.29 A*M −1 with a detection limit of 0.31 μM and a linear detection range from 0.39 μM to 8.98 μM for catechol. The calibration curve followed the Michaelis–Menten kinetics and the apparent Michaelis–Menten (K M app ) was 6.28 μM. This work demonstrated that the N-OMC/PVA composite provides a suitable support for laccase immobilization and the construction of a biosensor. (papers)

  19. Mesoporous Spinel Li4Ti5O12 Nanoparticles for High Rate Lithium-ion Battery Anodes

    International Nuclear Information System (INIS)

    Liu, Weijian; Shao, Dan; Luo, Guoen; Gao, Qiongzhi; Yan, Guangjie; He, Jiarong; Chen, Dongyang; Yu, Xiaoyuan; Fang, Yueping

    2014-01-01

    Graphical abstract: - Highlights: • Mesoporous Li 4 Ti 5 O 12 nanoparticles were prepared by a simple hydrothermal method. • The mesoporous Li 4 Ti 5 O 12 nanoparticles exhibited a diameter of 40 ± 5 nm and a pore-size distribution of 6 - 8 nm. • Cells with the mesoporous Li 4 Ti 5 O 12 anode showed excellent high rate electrochemical properties. - Abstract: Mesoporous spinel lithium titanate (Li 4 Ti 5 O 12 ) nanoparticles with the diameter of 40 ± 5 nm and the pore-size distribution of 6 - 8 nm were prepared by a simple hydrothermal method. As an anode material for lithium-ion batteries, these spinel Li 4 Ti 5 O 12 mesoporous nanoparticles exhibited desirable lithium storage properties with an initial discharge capacity of 176 mAh g −1 at 1 C rate and a capacity of approximately 145 mAh g −1 after 200 cycles at a high rate of 20 C. These excellent electrochemical properties at high charge/discharge rates are due to the mesoporous nano-scale structures with small size particles, uniform mesopores and larger electrode/electrolyte contact area, which shortens the diffusion path for both electrons and Li + ions, and offers more active sites for Li + insertion-extraction process

  20. Mesoporous Carbon Produced from Tri-constituent Mesoporous Carbon-silica Composite for Water Purification

    KAUST Repository

    Yu, Yanjie

    2012-01-01

    Highly ordered mesoporous carbon-silica nanocomposites with interpenetrating carbon and silica networks were synthesized by the evaporation-induced tri-constituent co- assembly approach. The removal of silica by concentrated NaOH solution produced mesoporous carbons, which contained not only the primary large pores, but also the secondary mesopores in the carbon walls. The thus synthesized mesoporous carbon was further activated by using ZnCl2. The activated mesoporous carbon showed an improved surface area and pore volume. The synthesized mesoporous carbon was tested for diuron removal from water and the results showed that the carbon gave a fast diuron adsorption kinetics and a high diuron removal capacity, which was attributable to the primary mesopore channels being the highway for mass transfer, which led to short diffusion path length and easy accessibility of the interpenetrated secondary mesopores. The optimal adsorption capacity of the porous carbon was determined to be 390 mg/g, the highest values ever reported for diuron adsorption on carbon-based materials.

  1. Mesoporous Carbon Produced from Tri-constituent Mesoporous Carbon-silica Composite for Water Purification

    KAUST Repository

    Yu, Yanjie

    2012-05-01

    Highly ordered mesoporous carbon-silica nanocomposites with interpenetrating carbon and silica networks were synthesized by the evaporation-induced tri-constituent co- assembly approach. The removal of silica by concentrated NaOH solution produced mesoporous carbons, which contained not only the primary large pores, but also the secondary mesopores in the carbon walls. The thus synthesized mesoporous carbon was further activated by using ZnCl2. The activated mesoporous carbon showed an improved surface area and pore volume. The synthesized mesoporous carbon was tested for diuron removal from water and the results showed that the carbon gave a fast diuron adsorption kinetics and a high diuron removal capacity, which was attributable to the primary mesopore channels being the highway for mass transfer, which led to short diffusion path length and easy accessibility of the interpenetrated secondary mesopores. The optimal adsorption capacity of the porous carbon was determined to be 390 mg/g, the highest values ever reported for diuron adsorption on carbon-based materials.

  2. Highly mesoporous single-crystalline zeolite beta synthesized using a nonsurfactant cationic polymer as a dual-function template

    KAUST Repository

    Zhu, Jie

    2014-02-12

    Mesoporous zeolites are useful solid catalysts for conversion of bulky molecules because they offer fast mass transfer along with size and shape selectivity. We report here the successful synthesis of mesoporous aluminosilicate zeolite Beta from a commercial cationic polymer that acts as a dual-function template to generate zeolitic micropores and mesopores simultaneously. This is the first demonstration of a single nonsurfactant polymer acting as such a template. Using high-resolution electron microscopy and tomography, we discovered that the resulting material (Beta-MS) has abundant and highly interconnected mesopores. More importantly, we demonstrated using a three-dimensional electron diffraction technique that each Beta-MS particle is a single crystal, whereas most previously reported mesoporous zeolites are comprised of nanosized zeolitic grains with random orientations. The use of nonsurfactant templates is essential to gaining single-crystalline mesoporous zeolites. The single-crystalline nature endows Beta-MS with better hydrothermal stability compared with surfactant-derived mesoporous zeolite Beta. Beta-MS also exhibited remarkably higher catalytic activity than did conventional zeolite Beta in acid-catalyzed reactions involving large molecules. © 2014 American Chemical Society.

  3. Control of ordered mesoporous titanium dioxide nanostructures formed using plasma enhanced glancing angle deposition

    Energy Technology Data Exchange (ETDEWEB)

    Gibson, Des [Institute of Thin Films, Sensors & Imaging, Scottish Universities Physics Alliance, University of West of Scotland, Paisley, PA1 2BE (United Kingdom); Child, David, E-mail: david.child@uws.ac.uk [Institute of Thin Films, Sensors & Imaging, Scottish Universities Physics Alliance, University of West of Scotland, Paisley, PA1 2BE (United Kingdom); Song, Shigeng; Zhao, Chao [Institute of Thin Films, Sensors & Imaging, Scottish Universities Physics Alliance, University of West of Scotland, Paisley, PA1 2BE (United Kingdom); Alajiani, Yahya [Institute of Thin Films, Sensors & Imaging, Scottish Universities Physics Alliance, University of West of Scotland, Paisley, PA1 2BE (United Kingdom); Department of Physics, Faculty of Science, Jazan University, Jazan (Saudi Arabia); Waddell, Ewan [Thin Film Solutions Ltd, West of Scotland Science Park, Glasgow, G20 0TH (United Kingdom)

    2015-10-01

    Three dimensional nanostructures of mesoporous (pore diameter between 2-50 nm) nanocrystalline titania (TiO{sub 2}) were produced using glancing angle deposition combined with plasma ion assisted deposition, providing plasma enhanced glancing angle deposition eliminating the need for post-annealing to achieve film crystallinity. Electron beam evaporation was chosen to deposit nanostructures at various azimuthal angles, achieving designed variation in three dimensional nanostructure. A thermionic broad beam hollow cathode plasma source was used to enhance electron beam deposition, with ability to vary in real time ion fluxes and energies providing a means to modify and control TiO{sub 2} nanostructure real time with controlled density and porosity along and lateral to film growth direction. Plasma ion assisted deposition was carried out at room temperature using a hollow cathode plasma source, ensuring low heat loading to the substrate during deposition. Plasma enhanced glancing angle TiO{sub 2} structures were deposited onto borosilicate microscope slides and used to characterise the effects of glancing angle and plasma ion energy distribution function on the optical and nanostructural properties. Variation in TiO{sub 2} refractive index from 1.40 to 2.45 (@ 550 nm) using PEGLAD is demonstrated. Results and analysis of the influence of plasma enhanced glancing angle deposition on evaporant path and resultant glancing angle deviation from standard GLAD are described. Control of mesoporous morphology is described, providing a means of optimising light trapping features and film porosity, relevant to applications such as fabrication of dye sensitised solar cells. - Highlights: • Plasma assistance during glancing angle deposition enables control of morphology. • Ion energy variation during glancing angle deposition varies columnar angle • Column thickness of glancing angle deposition dependant on ion current density • Ion current density variation during

  4. Optimization of fuel cell membrane electrode assemblies for transition metal ion-chelating ordered mesoporous carbon cathode catalysts

    Directory of Open Access Journals (Sweden)

    Johanna K. Dombrovskis

    2014-12-01

    Full Text Available Transition metal ion-chelating ordered mesoporous carbon (TM-OMC materials were recently shown to be efficient polymer electrolyte membrane fuel cell (PEMFC catalysts. The structure and properties of these catalysts are largely different from conventional catalyst materials, thus rendering membrane electrode assembly (MEA preparation parameters developed for conventional catalysts not useful for applications of TM-OMC catalysts. This necessitates development of a methodology to incorporate TM-OMC catalysts in the MEA. Here, an efficient method for MEA preparation using TM-OMC catalyst materials for PEMFC is developed including effects of catalyst/ionomer loading and catalyst/ionomer-mixing and application procedures. An optimized protocol for MEA preparation using TM-OMC catalysts is described.

  5. Fabrication of high specificity hollow mesoporous silica nanoparticles assisted by Eudragit for targeted drug delivery.

    Science.gov (United States)

    She, Xiaodong; Chen, Lijue; Velleman, Leonora; Li, Chengpeng; Zhu, Haijin; He, Canzhong; Wang, Tao; Shigdar, Sarah; Duan, Wei; Kong, Lingxue

    2015-05-01

    Hollow mesoporous silica nanoparticles (HMSNs) are one of the most promising carriers for effective drug delivery due to their large surface area, high volume for drug loading and excellent biocompatibility. However, the non-ionic surfactant templated HMSNs often have a broad size distribution and a defective mesoporous structure because of the difficulties involved in controlling the formation and organization of micelles for the growth of silica framework. In this paper, a novel "Eudragit assisted" strategy has been developed to fabricate HMSNs by utilising the Eudragit nanoparticles as cores and to assist in the self-assembly of micelle organisation. Highly dispersed mesoporous silica spheres with intact hollow interiors and through pores on the shell were fabricated. The HMSNs have a high surface area (670 m(2)/g), small diameter (120 nm) and uniform pore size (2.5 nm) that facilitated the effective encapsulation of 5-fluorouracil within HMSNs, achieving a high loading capacity of 194.5 mg(5-FU)/g(HMSNs). The HMSNs were non-cytotoxic to colorectal cancer cells SW480 and can be bioconjugated with Epidermal Growth Factor (EGF) for efficient and specific cell internalization. The high specificity and excellent targeting performance of EGF grafted HMSNs have demonstrated that they can become potential intracellular drug delivery vehicles for colorectal cancers via EGF-EGFR interaction. Copyright © 2014 Elsevier Inc. All rights reserved.

  6. Ultrathin mesoporous Co3O4 nanosheets on Ni foam for high-performance supercapacitors

    International Nuclear Information System (INIS)

    Qiu, Kangwen; Lu, Yang; Cheng, Jinbing; Yan, Hailong; Hou, Xiaoyi; Zhang, Deyang; Lu, Min; Liu, Xianming; Luo, Yongsong

    2015-01-01

    Ultrathin Co 3 O 4 nanosheets with a mesoporous structure and a large surface area are hydrothermally grown on a three dimensional nickel foam. The ultrathin mesoporous Co 3 O 4 nanosheets are grown on Ni foam with robust adhesion, which endows fast ion and electron transport, large electroactive surface area, and excellent structural stability. Such unique nanoarchitecture exhibits remarkable electrochemical performance with high capacitance and desirable cycle life. When evaluate as an electrode material for supercapacitors, the Co 3 O 4 nanosheets electrode is able to deliver high specific capacitance of 2194 F g −1 at a current density of 1 A g −1 in 1 M KOH aqueous solution. The electrode also exhibits excellent cycling stability by retaining 93.1% of the maximum capacitance after 5000 charge-discharge cycles. The fabrication strategy presented here is facile, cost-effective, and can offer a way for energy storage device applications

  7. High surface area mesoporous activated carbon-alginate beads for efficient removal of methylene blue.

    Science.gov (United States)

    Nasrullah, Asma; Bhat, A H; Naeem, Abdul; Isa, Mohamed Hasnain; Danish, Mohammed

    2018-02-01

    High surface area mesoporous activated carbon-alginate (AC-alginate) beads were successfully synthesized by entrapping activated carbon powder derived from Mangosteen fruit peel into calcium-alginate beads for methylene blue (MB) removal from aqueous solution. The structure and surface characteristics of AC-alginate beads were analyzed using Fourier transform infra-red (FTIR) spectroscopy, scanning electron microscopy (SEM) and surface area analysis (S BET ), while thermal properties were tested using thermogravimetric analysis (TGA). The effect of AC-alginate dose, pH of solution, contact time, initial concentration of MB solution and temperature on MB removal was elucidated. The results showed that the maximum adsorption capacity of 230mg/g was achieved for 100mg/L of MB solution at pH 9.5 and temperature 25°C. Furthermore, the adsorption of MB on AC-alginate beads followed well pseudo-second order equation and equilibrium adsorption data were better fitted by the Freundlich isotherm model. The findings reveal the feasibility of AC-alginate beads composite to be used as a potential and low cost adsorbent for removal of cationic dyes. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Hierarchical mesoporous graphene@Ni-Co-S arrays on nickel foam for high-performance supercapacitors

    International Nuclear Information System (INIS)

    Nguyen, Van Hoa; Lamiel, Charmaine; Shim, Jae-Jin

    2015-01-01

    Highlights: • Hierarchical mesoporous graphene@Ni-Co-S arays have been decorated on Ni foam. • The electrode exhibits a high specific capacitance of 9.2 F cm −1 at 100 mA cm −1 . • The electrode presents large electroactive surface area and excellent structural stability. - Abstract: Hierarchical mesoporous graphene and ternary nickel cobalt sulfide (Ni-Co-S) arrays on nickel foam were designed and fabricated by chemical vapor deposition and electrodeposition for supercapacitor applications. The electrodes exhibited rapid electron and ion transport, large electroactive surface area, and excellent structural stability owing to the highly conductive, mesoporous nature of graphene and the Ni-Co-S nanosheets, as well as to the open framework of the three-dimensional nanoarchitectures. The specific capacitance of the obtained electrode was as high as 9.2 F cm −1 at a high current density of 100 mA cm −1 , indicating promising applications as an efficient electrode for electrochemical capacitors

  9. Template-free synthesis of mesoporous nanoring-like Zn-Co mixed oxides with high lithium storage performance

    Science.gov (United States)

    Lu, Lun; Gao, Yan-Li; Yang, Zhi-Zheng; Wang, Cheng; Wang, Jin-Guo; Wang, Hui-Yuan; Jiang, Qi-Chuan

    2018-04-01

    Mesoporous nanoring-like Zn-Co mixed oxides are synthesized via a simple template-free solvothermal method with a subsequent annealing process. The ring-like nanostructures with hollow interiors are formed under the complexing effects of potassium sodium tartrate. Numerous mesopores are generated after the precursor is annealed at 500 °C. When applied as anode materials, the mesoporous nanoring-like Zn-Co mixed oxides can deliver a high discharge capacity of 1102 mAh g-1 after 200 cycles at 500 mA g-1. Even when the current density is increased to 2 A g-1, the mixed oxides can still retain a reversible capacity of 761 mAh g-1. Such high cycling stability and rate capability are mainly derived from the unique mesoporous ring-like nanostructures and the synergistic effects between Zn and Co based oxides.

  10. Fabrication of mesoporous and high specific surface area lanthanum carbide-carbon nanotube composites

    International Nuclear Information System (INIS)

    Biasetto, L.; Carturan, S.; Maggioni, G.; Zanonato, P.; Bernardo, P. Di; Colombo, P.; Andrighetto, A.; Prete, G.

    2009-01-01

    Mesoporous lanthanum carbide-carbon nanotube composites were produced by means of carbothermal reaction of lanthanum oxide, graphite and multi-walled carbon nanotube mixtures under high vacuum. Residual gas analysis revealed the higher reactivity of lanthanum oxide towards carbon nanotubes compared to graphite. After sintering, the composites revealed a specific surface area increasing with the amount of carbon nanotubes introduced. The meso-porosity of carbon nanotubes was maintained after thermal treatment.

  11. Functionalized Mesoporous Silica Membranes for CO2 Separation Applications

    Directory of Open Access Journals (Sweden)

    Hyung-Ju Kim

    2015-01-01

    Full Text Available Mesoporous silica molecular sieves are emerging candidates for a number of potential applications involving adsorption and molecular transport due to their large surface areas, high pore volumes, and tunable pore sizes. Recently, several research groups have investigated the potential of functionalized mesoporous silica molecular sieves as advanced materials in separation devices, such as membranes. In particular, mesoporous silica with a two- or three-dimensional pore structure is one of the most promising types of molecular sieve materials for gas separation membranes. However, several important challenges must first be addressed regarding the successful fabrication of mesoporous silica membranes. First, a novel, high throughput process for the fabrication of continuous and defect-free mesoporous silica membranes is required. Second, functionalization of mesopores on membranes is desirable in order to impart selective properties. Finally, the separation characteristics and performance of functionalized mesoporous silica membranes must be further investigated. Herein, the synthesis, characterization, and applications of mesoporous silica membranes and functionalized mesoporous silica membranes are reviewed with a focus on CO2 separation.

  12. Structural analysis and characterization of synthesized ordered mesoporous silicate (MCM-41) using small angle X-rays scattering and complementary techniques

    Science.gov (United States)

    Akinlalu, Ademola V.

    Mesoporous silicate have widespread potential applications, such as drug delivery, supports for catalysis, selective adsorption and host to guest molecules. Most important in the area of scientific research and industrial applications is their demand due to its extremely high surface areas (> 800m 2g-1) and larger pores with well defined structures. Mesoporous silicate (MCM-41) samples were prepared by hydrothermal method under various chemo-physical conditions and various experimental methods such as small angle X-rays scattering (SAXS), Nitrogen adsorption-desorption analysis at 77 K, Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) were employed to investigate the changes in the structural morphology and subtle lattice parameter changes. With regards to the subtle changes in the structural characteristics of the synthesized mesoporous silicate, we seek to understand the electron density function changes as the synthesis parameter are varied from low molar concentration of ATAB/Si to higher concentration, the system becoming more acidity due to increase in the hydrolysis time of pH regulator as a result of increased production of ethanol and acetic acid and the changes due to extended reaction time. This Ph.D. research tries to understand the influence of various parameters like surfactant-Si molar ratio, reaction time, and the hydrolysis of the pH regulator on the orderliness/disorderliness of the lattice order, lattice spacing and electron density function. The stages during synthesis are carefully selected to better understand where the greater influence on the overall structural morphology exist so as to be able to ne tune this parameter for any desired specification and application. The SAXS measurement were conducted on a HECUS S3-Micro X-ray system at Rensselaer Polytechnic Institute, Troy, NY. while the data evaluation and visualization were carried in 3DView 4.2 and EasySWAXS software. The electron density functions

  13. Enabling high-rate electrochemical flow capacitors based on mesoporous carbon microspheres suspension electrodes

    Science.gov (United States)

    Tian, Meng; Sun, Yueqing; Zhang, Chuanfang (John); Wang, Jitong; Qiao, Wenming; Ling, Licheng; Long, Donghui

    2017-10-01

    Electrochemical flow capacitor (EFC) is a promising technology for grid energy storage, which combines the fast charging/discharging capability of supercapacitors with the scalable energy capacity of flow batteries. In this study, we report a high-power-density EFC using mesoporous carbon microspheres (MCMs) as suspension electrodes. By using a simple yet effective spray-drying technique, monodispersed MCMs with average particle size of 5 μm, high BET surface area of 1150-1267 m2 g-1, large pore volume of 2-4 cm3 g-1 and controllable mesopore size of 7-30 nm have been successfully prepared. The resultant MCMs suspension electrode shows excellent stability and considerable high capacitance of 100 F g-1 and good cycling ability (86% of initial capacitance after 10000 cycles). Specially, the suspension electrode exhibits excellent rate performance with 75% capacitance retention from 2 to 100 mV s-1, significantly higher than that of microporous carbon electrodes (20∼30%), due to the developed mesoporous channels facilitating for rapid ion diffusion. In addition, the electrochemical responses on both negative and positive suspension electrodes are studied, based on which an optimal capacitance matching between them is suggested for large-scale EFC unit.

  14. Prussian blue mediated amplification combined with signal enhancement of ordered mesoporous carbon for ultrasensitive and specific quantification of metolcarb by a three-dimensional molecularly imprinted electrochemical sensor.

    Science.gov (United States)

    Yang, Yukun; Cao, Yaoyu; Wang, Xiaomin; Fang, Guozhen; Wang, Shuo

    2015-02-15

    In this work, we presented a three-dimensional (3D) molecularly imprinted electrochemical sensor (MIECS) with novel strategy for ultrasensitive and specific quantification of metolcarb based on prussian blue (PB) mediated amplification combined with signal enhancement of ordered mesoporous carbon. The molecularly imprinted polymers were synthesized by electrochemically induced redox polymerization of para aminobenzoic acid (p-ABA) in the presence of template metolcarb. Ordered mesoporous carbon material (CMK-3) was introduced to enhance the electrochemical response by improving the structure of the modified electrodes and facilitating charge transfer processes of PB which was used as an inherent electrochemical active probe. The modification process for the working electrodes of the MIECS was characterized by scanning electron microscope (SEM) and cyclic voltammetry (CV), and several important parameters controlling the performance of the MIECS were investigated and optimized in detail. The MIECS with 3D structure had the advantages of ease of preparation, high porous surface structure, speedy response, ultrasensitivity, selectivity, reliable stability, good reproducibility and repeatability. Under the optimal conditions, the MIECS offered an excellent current response for metolcarb in the linear response range of 5.0 × 10(-10)-1.0 × 10(-4) mol L(-1) and the limit of detection (LOD) was calculated to be 9.3 × 10 (-11)mol L(-1) (S/N = 3). The proposed MIECS has been successfully applied for the determination of metolcarb in real samples with satisfactory recoveries. Furthermore, the construction route of this ultrasensitive 3D MIECS may provide a guideline for the determination of non-electroactive analytes in environmental control and food safety. Copyright © 2014 Elsevier B.V. All rights reserved.

  15. A high-performance mesoporous carbon supported nitrogen-doped carbon electrocatalyst for oxygen reduction reaction

    Science.gov (United States)

    Xu, Jingjing; Lu, Shiyao; Chen, Xu; Wang, Jianan; Zhang, Bo; Zhang, Xinyu; Xiao, Chunhui; Ding, Shujiang

    2017-12-01

    Investigating low-cost and highly active electrocatalysts for oxygen reduction reactions (ORR) is of crucial importance for energy conversion and storage devices. Herein, we design and prepare mesoporous carbon supported nitrogen-doped carbon by pyrolysis of polyaniline coated on CMK-3. This electrocatalyst exhibits excellent performance towards ORR in alkaline media. The optimized nitrogen-doped mesoporous electrocatalyst show an onset potential (E onset) of 0.95 V (versus reversible hydrogen electrode (RHE)) and half-wave potential (E 1/2) of 0.83 V (versus RHE) in 0.1 M KOH. Furthermore, the as-prepared catalyst presents superior durability and methanol tolerance compared to commercial Pt/C indicating its potential applications in fuel cells and metal-air batteries.

  16. Mesoporous Silicate Materials in Sensing

    Directory of Open Access Journals (Sweden)

    Paul T. Charles

    2008-08-01

    Full Text Available Mesoporous silicas, especially those exhibiting ordered pore systems and uniform pore diameters, have shown great potential for sensing applications in recent years. Morphological control grants them versatility in the method of deployment whether as bulk powders, monoliths, thin films, or embedded in coatings. High surface areas and pore sizes greater than 2 nm make them effective as adsorbent coatings for humidity sensors. The pore networks also provide the potential for immobilization of enzymes within the materials. Functionalization of materials by silane grafting or through cocondensation of silicate precursors can be used to provide mesoporous materials with a variety of fluorescent probes as well as surface properties that aid in selective detection of specific analytes. This review will illustrate how mesoporous silicas have been applied to sensing changes in relative humidity, changes in pH, metal cations, toxic industrial compounds, volatile organic compounds, small molecules and ions, nitroenergetic compounds, and biologically relevant molecules.

  17. Synthesis and characterization of novel mesocomposites Co3O4 and CuO@OMS (ordered mesoporous silica) as active catalysts for hydrocarbon oxidation

    Science.gov (United States)

    Comănescu, Cezar

    2014-03-01

    Novel metal nanoporous transition metal oxides M x O y (Co3O4, CuO) have been synthesized by thermal decomposition of inorganic salts precursors (acetates, nitrates) impregnated into hexagonal mesoporous silica (OMS, ordered mesoporous silica) of SBA-15 type (prepared in-house) at different precursor loadings, the mesocomposites thus obtained being monitored after each impregnation-calcination step by small and wide angle powder XRD. The pore size for the ordered silica host range from 5.08 to 7.06 nm. Retention of the hexagonal silica framework has been observed in spite of the temperatures up to 500 °C. Mesoporous Co3O4 has been obtained by leaching the silica through overnight HF dissolution, which partially preserved the small-range ordering found in the parent Co3O4@OMS composite prior to leaching. Both Co3O4 ( meso) and Co3O4@SBA-15 have been tested in methane oxidation and were found to be superior to the bulk Co3O4 performance, with mesoporous Co3O4 being able to fully oxidize methane to CO2 and H2O at 350 °C, while Co3O4@OMS exhibits a lower activity with 20 % conversion at 350 °C. CuO@OMS shows the lowest activity, with only 13 % conversion at 500 °C.

  18. Gyroidal mesoporous carbon materials and methods thereof

    Energy Technology Data Exchange (ETDEWEB)

    Wiesner, Ulrich B.; Werner, Joerg G.

    2017-07-25

    The present invention relates to, inter alia, gyroidal mesoporous carbon materials and methods of use and manufacture thereof. In one embodiment, the present invention relates to a mesoporous carbon composition comprising a gyroidal mesoporous carbon having an ordered gyroidal structure and mesopores having a pore size of greater than 2 nanometers (nm) in diameter, and more particularly greater than 11 nm in diameter.

  19. Amine-modified ordered mesoporous silica: The effect of pore size on CO{sub 2} capture performance

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Lin; Yao, Manli [Key Laboratory of the Ministry of Education for Advanced Catalysis Materials, Institute of Physical Chemistry, Zhejiang Normal University, Jinhua 321004 (China); Hu, Xin [College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua 321004 (China); Hu, Gengshen, E-mail: gshu@zjnu.edu.cn [Key Laboratory of the Ministry of Education for Advanced Catalysis Materials, Institute of Physical Chemistry, Zhejiang Normal University, Jinhua 321004 (China); Lu, Jiqing; Luo, Mengfei [Key Laboratory of the Ministry of Education for Advanced Catalysis Materials, Institute of Physical Chemistry, Zhejiang Normal University, Jinhua 321004 (China); Fan, Maohong, E-mail: mfan@uwyo.edu [Department of Chemical and Petroleum Engineering, University of Wyoming, Laramie, WY 82071 (United States)

    2015-01-01

    Highlights: • Larger pore size could decrease the mass transfer resistance and increase the interaction between CO{sub 2} and TEPA. • The CO{sub 2} uptakes of sorbents were enhanced in the presence of moisture. • The sorbents are stable and regenerable under test conditions. - Abstract: The objective of current research is to investigate the effect of pore size of mesoporous silica supports on the CO{sub 2} capture performance of solid amine sorbents. Two ordered mesoporous silicas (OMS) with different pore sizes (5.6 nm and 7.6 nm) were synthesized as tetraethylenepentamine (TEPA) supports. A serious of techniques, such as physical adsorption, infrared spectroscopy and thermal gravimetric analysis were used to characterize the solid amine sorbents. The CO{sub 2} capture performances of the sorbents were evaluated using breakthrough method with a fixed-bed reactor equipped with an online mass spectrometer. The experimental results indicate that the pore size has significant influence on CO{sub 2} capture performance. Larger pore size could decrease the mass transfer resistance and increase the interaction between CO{sub 2} and TEPA. Therefore, OMS-7.6 is better than OMS-5.6 as amine support. The highest CO{sub 2} sorption capacities achieved with OMS-7.6 with 50 wt% TEPA loading (OMS-7.6-50) in the absence and presence of moisture are 3.45 mmol/g and 4.28 mmol/g, respectively, under the conditions of 10.0% CO{sub 2}/N{sub 2} mixture at 75 °C. Cyclic CO{sub 2} adsorption–desorption experiments indicate that the solid amine sorbents are fairly stable and regenerable.

  20. Physical state of poorly water soluble therapeutic molecules loaded into SBA-15 ordered mesoporous silica carriers: a case study with itraconazole and ibuprofen.

    Science.gov (United States)

    Mellaerts, Randy; Jammaer, Jasper A G; Van Speybroeck, Michiel; Chen, Hong; Van Humbeeck, Jan; Augustijns, Patrick; Van den Mooter, Guy; Martens, Johan A

    2008-08-19

    The ordered mesoporous silica material SBA-15 was loaded with the model drugs itraconazole and ibuprofen using three different procedures: (i) adsorption from solution, (ii) incipient wetness impregnation, and (iii) heating of a mixture of drug and SBA-15 powder. The location of the drug molecules in the SBA-15 particles and molecular interactions were investigated using nitrogen adsorption, TGA, DSC, DRS UV-vis, and XPS. The in vitro release of hydrophobic model drugs was evaluated in an aqueous environment simulating gastric fluid. The effectiveness of the loading method was found to be strongly compound dependent. Incipient wetness impregnation using a concentrated itraconazole solution in dichloromethane followed by solvent evaporation was most efficient for dispersing itraconazole in SBA-15. The itraconazole molecules were located on the mesopore walls and inside micropores of the mesopore walls. When SBA-15 was loaded by slurrying it in a diluted itraconazole solution from which the solvent was evaporated, the itraconazole molecules ended up in the mesopores that they plugged locally. At a loading of 30 wt %, itraconazole exhibited intermolecular interactions inside the mesopores revealed by UV spectroscopy and endothermic events traced with DSC. The physical mixing of itraconazole and SBA-15 powder followed by heating above the itraconazole melting temperature resulted in formulations in which glassy itraconazole particles were deposited externally on the SBA-15 particles. Loading with ibuprofen was successful with each of the three loading procedures. Ibuprofen preferably is positioned inside the micropores. In vitro release experiments showed fast release kinetics provided the drug molecules were evenly deposited over the mesoporous surface.

  1. Generation of high order modes

    CSIR Research Space (South Africa)

    Ngcobo, S

    2012-07-01

    Full Text Available with the location of the Laguerre polynomial zeros. The Diffractive optical element is used to shape the TEM00 Gassian beam and force the laser to operate on a higher order TEMp0 Laguerre-Gaussian modes or high order superposition of Laguerre-Gaussian modes...

  2. Ordered mesoporous carbon film as an effective solid-phase microextraction coating for determination of benzene series from aqueous media

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Hui [Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094 (China); School of Geography Science, Nantong University, Nantong 226001 (China); Li, Jiansheng, E-mail: lijsh@mail.njust.edu.cn [Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094 (China); Jiang, Mingyue; Lu, Rui; Shen, Jinyou; Sun, Xiuyun; Han, Weiqing [Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094 (China); Wang, Lianjun, E-mail: wanglj@mail.njust.edu.cn [Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094 (China)

    2015-08-12

    The present work reports preparation of ordered mesoporous carbon (OMC) film supported on a graphite fiber as a new type of solid-phase microextraction (SPME) fiber for determination of benzene series from aqueous media. The strategy for the supported OMC film preparation was combined dip-coating technology with solvent evaporation-induced self-assembly (EISA) approach. A graphite fiber was immersed in an ethanol solution containing phenolic resin and Pluronic triblock copolymer. Upon solvent evaporation and subsequent pyrolysis under 700 °C, the phenolic resin and the surfactant self-assembled on the surface of the graphite fiber to form smooth OMC film. X-ray diffraction (XRD), transmission electron microscopy (TEM) and nitrogen isothermal adsorption results indicate that the resultant OMC film possesses well-ordered two dimensional hexagonal mesostructure with pore diameters of 4.5 nm and BET surfaces of 630 m{sup 2}/g. Scanning electron microscopy (SEM) studies show the supported OMC film with thickness at 8.5 μm is continuous and defect-free. The SPME efficiency of the OMC fiber was evaluated by analysis of five benzene series (benzene, toluene, ethylbenzene, p-xylene and m-xylene) from water samples by gas chromatography-flame ionization detection (GC-FID). The analysis results indicate that the prepared OMC fiber has wide linear ranges (0.5–500 μg/L), low detection limits (0.01–0.05 μg/L) and good repeatabilities (4.0–5.8% for one fiber, 2.9–8.7% for fiber-to-fiber). Compared with commercial counterparts, the OMC fiber exhibits improved extraction efficiency for benzene series and PAHs. - Highlights: • Ordered mesoporous carbon film supported on graphite fiber was first reported as solid-phase microextraction coating. • The strategy for the film preparation was combined dip-coating technology with evaporation-induced self-assembly approach. • The obtained fiber showed enhanced thermal stability and organic solvents resistance. • The

  3. High order depletion sensitivity analysis

    International Nuclear Information System (INIS)

    Naguib, K.; Adib, M.; Morcos, H.N.

    2002-01-01

    A high order depletion sensitivity method was applied to calculate the sensitivities of build-up of actinides in the irradiated fuel due to cross-section uncertainties. An iteration method based on Taylor series expansion was applied to construct stationary principle, from which all orders of perturbations were calculated. The irradiated EK-10 and MTR-20 fuels at their maximum burn-up of 25% and 65% respectively were considered for sensitivity analysis. The results of calculation show that, in case of EK-10 fuel (low burn-up), the first order sensitivity was found to be enough to perform an accuracy of 1%. While in case of MTR-20 (high burn-up) the fifth order was found to provide 3% accuracy. A computer code SENS was developed to provide the required calculations

  4. Functionalisation of mesoporous materials for application as additives in high temperature PEM fuel cell membranes

    Energy Technology Data Exchange (ETDEWEB)

    Sharifi, Monir

    2012-03-06

    The presented thesis contains six original research articles dedicated to the preparation and characterization of organic-inorganic mesoporous materials as additives for polymer electroly1e membrane fuel cells (PEMFCs). The mesoporous materials Si-MCM-41 and benzene-PMO (periodic mesoporous organosilica) were chosen for the investigations. These materials were modified with functional groups for enhanced proton conductivity and water-keeping properties. In order to improve these materials Broenstedt acidic groups were introduced in the framework of mesoporous Si-MCM-41. Therefore, some silicium atoms in the framework were substituted by aluminium using different aluminium sources. Here NaAlO{sub 2} exhibits clearly the best results because the entire aluminium incorporated within the framework is tetragonally coordinated as observed by {sup 2}7AI MAS NMR. The increase of the proton conductivities results from an improved hydrophilicity, a decreased particle size, and newly introduced Broenstedt acidity in the mesoporous Al-MCM-41. However, mesoporous Si-MCM-41 materials functionalised by co-condensation with sulphonic acid groups exhibit the best results concerning proton conductivity, compared to those prepared by grafting. Hence, these materials where characterized in more detail by SANS and by MAS NMR measurements. The first one indicated that by co-condensation the entire inner pore surface is altered by functional groups which are, thus, distributed much more homogeneously than samples functionalised by grafting. This result explains the improved proton conductivities. Additionally, {sup 2}9Si NMR spectra proved that samples prepared by co-condensation lead to a successful and almost complete incorporation of mercaptopropyltrimethoxysilan (MPMS) into the mesoporous framework. Furthermore, it was shown by {sup 1}3C MAS NMR spectroscopy that the majority of the organic functional groups remained intact after H{sub 2}0{sub 2}-oxidation. However, proton

  5. Tunable conductivity in mesoporous germanium

    Science.gov (United States)

    Beattie, Meghan N.; Bioud, Youcef A.; Hobson, David G.; Boucherif, Abderraouf; Valdivia, Christopher E.; Drouin, Dominique; Arès, Richard; Hinzer, Karin

    2018-05-01

    Germanium-based nanostructures have attracted increasing attention due to favourable electrical and optical properties, which are tunable on the nanoscale. High densities of germanium nanocrystals are synthesized via electrochemical etching, making porous germanium an appealing nanostructured material for a variety of applications. In this work, we have demonstrated highly tunable electrical conductivity in mesoporous germanium layers by conducting a systematic study varying crystallite size using thermal annealing, with experimental conductivities ranging from 0.6 to 33 (×10‑3) Ω‑1 cm‑1. The conductivity of as-prepared mesoporous germanium with 70% porosity and crystallite size between 4 and 10 nm is shown to be ∼0.9 × 10‑3 Ω‑1 cm‑1, 5 orders of magnitude smaller than that of bulk p-type germanium. Thermal annealing for 10 min at 400 °C further reduced the conductivity; however, annealing at 450 °C caused a morphological transformation from columnar crystallites to interconnecting granular crystallites and an increase in conductivity by two orders of magnitude relative to as-prepared mesoporous germanium caused by reduced influence of surface states. We developed an electrostatic model relating the carrier concentration and mobility of p-type mesoporous germanium to the nanoscale morphology. Correlation within an order of magnitude was found between modelled and experimental conductivities, limited by variation in sample uniformity and uncertainty in void size and fraction after annealing. Furthermore, theoretical results suggest that mesoporous germanium conductivity could be tuned over four orders of magnitude, leading to optimized hybrid devices.

  6. High performance of a unique mesoporous polystyrene-based adsorbent for blood purification.

    Science.gov (United States)

    Chen, Jian; Han, Wenyan; Chen, Jie; Zong, Wenhui; Wang, Weichao; Wang, Yue; Cheng, Guanghui; Li, Chunran; Ou, Lailiang; Yu, Yaoting

    2017-02-01

    A multi-functional polystyrene based adsorbent (NKU-9) with a unique mesoporous and a high surface area was prepared by suspension polymerization for removal of therapeutic toxins in blood purification. The adsorbent produced had an almost equal amount of mesopore distribution in the range from 2 to 50 nm. The adsorption of serum toxins with different molecular weights were examined by in vitro adsorption assays and compared with some clinical currently used adsorbents such as HA-330, Cytosorb and BL-300 which are produced by China, America and Japan, respectively. Test results indicated that the adsorption rate for pentobarbital by NKU-9 was 81.24% which is nearly as high as HA-330 (81.44%). The latter adsorbent is currently used for acute detoxification treatment in China. To reach adsorption equilibrium, NKU-9 was faster than HA-330, which implies short treatment time. For the removal of middle molecular toxins such as β2-microglobulin (98.88%), NKU-9 performed better adsorptive selectivity than Cytosorb (92.80%). In addition, NKU-9 showed high performance for the removal of albumin-bound toxins (e.g., bilirubin), and its adsorption rate for total bilirubin (80.79%) in plasma was 8.4% higher than that of anion exchange resin BL-300 which is currently used to eliminate bilirubin in clinic. Therefore, our results indicate that the newly developed adsorbent with a wide distribution and almost equal amount of mesopores is a multifunctional adsorbent for high efficient removal of serum toxins with different molecular weights which might be an excellent blood purification adsorbent especially to treat diseases that conventional medical methods are low or not efficient.

  7. Electrochemical determination of bisphenol A at ordered mesoporous carbon modified nano-carbon ionic liquid paste electrode.

    Science.gov (United States)

    Li, Yonghong; Zhai, Xiurong; Liu, Xinsheng; Wang, Ling; Liu, Herong; Wang, Haibo

    2016-02-01

    A simple bisphenol A (BPA) sensor was successfully fabricated based on ordered mesoporous carbon CMK-3 modified nano-carbon ionic liquid paste electrode (CMK-3/nano-CILPE). The nanostructure of CMK-3 and the surface morphologies of modified electrodes were characterized by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). Electrochemical properties of the fabricated electrodes were investigated by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The fabricated sensor displayed excellent electroactivity towards bisphenol A using linear sweep voltammetry (LSV). Experimental conditions influencing the analytical performance of the modified electrode were optimized. Under optimal conditions, the oxidation peak current was proportional to BPA concentration in the range from 0.2 μM to 150 μM with a detection limit of 0.05 μM (S/N=3). This method was successfully used for determination of BPA leached from drinking bottle and plastic bag with good recoveries. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. In-Situ Observation of Solid Electrolyte Interphase Formation in Ordered Mesoporous Hard Carbon by Small-Angle Neutron Scattering

    International Nuclear Information System (INIS)

    Bridges, Craig A.; Paranthaman, Mariappan Parans; Sun, Xiao-Guang; Zhao, Jinkui; Dai, Sheng

    2012-01-01

    The aim of this work was to better understand the electrochemical processes occurring during the cycling of a lithium-ion half-cell containing ordered mesoporous hard carbon using time-resolved in situ small-angle neutron scattering (SANS). Utilizing electrolytes containing mixtures of deuterated (2H) and non-deuterated (1H) carbonates, we have addressed the challenging task of monitoring the formation and evolution of the solid-electrolyte interphase (SEI) layer. An evolution occurs in the SEI layer during discharge from a composition dominated by a higher scattering length density (SLD) lithium salt, to a lower SLD lithium salt for the ethylene carbonate/dimethyl carbonate (EC/DMC) mixture employed. By comparing half-cells containing different solvent deuteration levels, we show that it is possible to observe both SEI formation and lithium intercalation occurring concurrently at the low voltage region in which lithium intercalates into the hard carbon. These results demonstrate that SANS can be employed to monitor complicated electrochemical processes occurring in rechargeable batteries, in a manner that simultaneously provides information on the composition and microstructure of the electrode.

  9. Crystalline mesoporous tungsten oxide nanoplate monoliths synthesized by directed soft template method for highly sensitive NO2 gas sensor applications

    International Nuclear Information System (INIS)

    Hoa, Nguyen Duc; Duy, Nguyen Van; Hieu, Nguyen Van

    2013-01-01

    Graphical abstract: Display Omitted Highlights: ► Mesoporous WO 3 nanoplate monoliths were obtained by direct templating synthesis. ► Enable effective accession of the analytic molecules for the sensor applications. ► The WO 3 sensor exhibited a high performance to NO 2 gas at low temperature. -- Abstract: Controllable synthesis of nanostructured metal oxide semiconductors with nanocrystalline size, porous structure, and large specific surface area is one of the key issues for effective gas sensor applications. In this study, crystalline mesoporous tungsten oxide nanoplate-like monoliths with high specific surface areas were obtained through instant direct-templating synthesis for highly sensitive nitrogen dioxide (NO 2 ) sensor applications. The copolymer soft template was converted into a solid carbon framework by heat treatment in an inert gas prior to calcinations in air to sustain the mesoporous structure of tungsten oxide. The multidirectional mesoporous structures of tungsten oxide with small crystalline size, large specific surface area, and superior physical characteristics enabled the rapid and effective accession of analytic gas molecules. As a result, the sensor response was enhanced and the response and recovery times were reduced, in which the mesoporous tungsten oxide based gas sensor exhibited a superior response of 21,155% to 5 ppm NO 2 . In addition, the developed sensor exhibited selective detection of low NO 2 concentration in ammonia and ethanol at a low temperature of approximately 150 °C.

  10. Mesoporous LiMnPO4/C nanoparticles as high performance cathode material for lithium ion batteries

    International Nuclear Information System (INIS)

    Wen, Fang; Shu, Hongbo; Zhang, Yuanyuan; Wan, Jiajia; Huang, Weihua; Yang, Xiukang; Yu, Ruizhi; Liu, Li; Wang, Xianyou

    2016-01-01

    LiMnPO 4 has been considered as one of the most promising high voltage cathode materials for next-generation lithium ion batteries. However, LiMnPO 4 suffers from intrinsic drawbacks of extremely low electronic conductivity and ionic diffusivity between LiMnPO 4 /MnPO 4 . In this paper, mesoporous LiMnPO 4 nanoparticles are synthesized successfully via a facile glycine-assisted solvothermal rout. The as-prepared mesoporous LiMnPO 4 /C nanoparticles present well-defined abundant mesoporous structure (diameter of 3 ∼ 10 nm), uniform carbon layer (thickness of 3 ∼ 4 nm), high specific surface area (90.1 m 2 /g). As a result, the mesoporous LiMnPO 4 /C nanoparticles achieve excellent electrochemical performance as cathode materials for lithium ion batteries. It demonstrates a high discharge capacity of 167.7, 161.6, 156.4, 148.4 and 128.7 mAh/g at 0.1, 0.5, 1, 2 and 5C, and maintains a discharge capacity of 130.0 mAh/g after 100 cycles at 1C. The good electrochemical performance is attributed to its special interpenetrating mesoporous structure in LiMnPO 4 nanoparticles, which significantly enhances the ionic and electronic transport and additional capacitive behavior to compensate the sluggish kinetics.

  11. Highly electroconductive mesoporous graphene nanofibers and their capacitance performance at 4 V.

    Science.gov (United States)

    Cui, Chaojie; Qian, Weizhong; Yu, Yuntao; Kong, Chuiyan; Yu, Bo; Xiang, Lan; Wei, Fei

    2014-02-12

    We report the fabrication of one-dimensional highly electroconductive mesoporous graphene nanofibers (GNFs) by a chemical vapor deposition method using MgCO3·3H2O fibers as the template. The growth of such a unique structure underwent the first in situ decomposition of MgCO3·3H2O fibers to porous MgO fibers, followed by the deposition of carbon on the MgO surface, the removal of MgO by acidic washing, and the final self-assembly of wet graphene from single to double layer in drying process. GNFs exhibited good structural stability, high surface area, mesopores in large amount, and electrical conductivity 3 times that of carbon nanotube aggregates. It, used as an electrode in a 4 V supercapacitor, exhibited high energy density in a wide range of high power density and excellent cycling stability. The short diffusion distance for ions of ionic liquids electrolyte to the surface of GNFs yielded high surface utilization efficiency and a capacitance up to 15 μF/cm(2), higher than single-walled carbon nanotubes.

  12. Selective adsorption and release of cationic organic dye molecules on mesoporous borosilicates

    International Nuclear Information System (INIS)

    Paul, Manidipa; Pal, Nabanita; Bhaumik, Asim

    2012-01-01

    Mesoporous materials can play a pivotal role as a host material for delivery application to a specific part of a system. In this work we explore the selective adsorption and release of cationic organic dye molecules such as safranine T (ST) and malachite green (MG) on mesoporous borosilicate materials. The mesoporous silica SBA-15 and borosilicate materials (MBS) were prepared using non-ionic surfactant Pluronic P123 as template via evaporation induced self-assembly (EISA) method. After template removal the materials show high surface areas and in some cases ordered mesopores of dimensions ca. 6–7 nm. High surface area, mesoporosity and the presence of heteroatom (boron) help this mesoporous borosilicate material to adsorb high amount of cationic dye molecules at its surface from the respective aqueous solutions. Furthermore, the mesoporous borosilicate samples containing higher percentage adsorbed dyes show excellent release of ST or MG dye in simulated body fluid (SBF) solution at physiological pH = 7.4 and temperature 310 K. The adsorption and release efficiency of mesoporous borosilicate samples are compared with reference boron-free mesoporous pure silica material to understand the nature of adsorbate–adsorbent interaction at the surfaces. - Graphical abstract: Highly ordered 2D-hexagonal mesoporous borosilicate materials have been synthesized by using Pluronic P123 as template. The materials show very good adsorption and release of organic cationic dye molecules under physiological conditions. Highlights: ► Highly ordered 2D-hexagonal mesoporous borosilicate. ► Nonionic Pluoronic P123 templated mesoporous material. ► Adsorption of organic dyes at the mesopore surface. ► Controlled release of dyes under physiological pH and temperature. ► Release of safranine T (ST) and malachite green (MG) dyes in simulated body fluids.

  13. Synthesis of magnetic CoFe2O4/ordered mesoporous carbon nanocomposites and application in Fenton-like oxidation of rhodamine B.

    Science.gov (United States)

    Deng, Jing; Chen, Yi-Jing; Lu, Yu-An; Ma, Xiao-Yan; Feng, Shan-Fang; Gao, Naiyun; Li, Jun

    2017-06-01

    CoFe 2 O 4 /ordered mesoporous carbon (OMC) nanocomposites were synthesized and tested as heterogeneous peroxymonosulfate (PMS) activator for the removal of rhodamine B. Characterization confirmed that CoFe 2 O 4 nanoparticles were tightly bonded to OMC, and the hybrid catalyst possessed high surface area, pore volume, and superparamagnetism. Oxidation experiments demonstrated that CoFe 2 O 4 /OMC nanocomposites displayed favorable catalytic activity in PMS solution and rhodamine B degradation could be well described by pseudo-first-order kinetic model. Sulfate radicals (SO 4 - ·) were verified as the primary reactive species which was responsible for the decomposition of rhodamine B. The optimum loading ratio of CoFe 2 O 4 and OMC was determined to be 5:1. Under optimum operational condition (catalyst dosage 0.05 g/L, PMS concentration 1.5 mM, pH 7.0, and 25 °C), CoFe 2 O 4 /OMC-activated peroxymonosulfate system could achieve almost complete decolorization of 100 mg/L rhodamine B within 60 min. The enhanced catalytic activity of CoFe 2 O 4 /OMC nanocomposites compared to that of CoFe 2 O 4 nanoparticles could be attributable to the increased adsorption capacity and accelerated redox cycles between Co(III)/Co(II) and Fe(III)/Fe(II).

  14. Incorporation of Pt, Ru and Pt-Ru nanoparticles into ordered mesoporous carbons for efficient oxygen reduction reaction in alkaline media

    International Nuclear Information System (INIS)

    Stojmenović, Marija; Momčilović, Milan; Gavrilov, Nemanja; Pašti, Igor A.; Mentus, Slavko; Jokić, Bojan; Babić, Biljana

    2015-01-01

    Ordered mesoporous carbon, volume-doped up to 3 w.% with Pt, Ru and Pt-Ru nanoparticles was synthesized by evaporation-induced self-assembly method, under acidic conditions. The content of incorporated metal was determined by EDX analysis. The X-ray diffractometry confirmed the existence of highly dispersed metallic phases in doped samples. Specific surface area was determined by N 2 -physisorption measurements to range between 452 and 545 m 2 g −1 . Raman spectroscopy of investigated materials indicated highly disordered carbon structure with crystallite sizes around 1.4 nm. In a form of thin-layer electrode on glassy carbon support, in 0.1 M KOH solution, the prepared materials displayed high activity toward oxygen reduction reaction (ORR) in alkaline media, with onset potentials more positive than −0.10 V vs. SCE. The kinetics of O 2 reduction was found to be affected by both the specific surface area and the concentration of metal dopants. The ethanol tolerance of (Pt, Ru)-doped OMCs was found to be higher than that of common Pt/C ORR catalysts. Presented study provides a new route for the synthesis of active and selective ORR catalysts in alkaline media, being competitive with, or superior to, the existing ones in terms of performance and price

  15. High-temperature synthesis of highly hydrothermal stable mesoporous silica and Fe-SiO2 using ionic liquid as a template

    International Nuclear Information System (INIS)

    Liu, Hong; Wang, Mengyang; Hu, Hongjiu; Liang, Yuguang; Wang, Yong; Cao, Weiran; Wang, Xiaohong

    2011-01-01

    Mesoporous silicas and Fe-SiO 2 with worm-like structures have been synthesized using a room temperature ionic liquid, 1-hexadecane-3-methylimidazolium bromide, as a template at a high aging temperature (150-190 o C) with the assistance of NaF. The hydrothermal stability of mesoporous silica was effectively improved by increasing the aging temperature and adding NaF to the synthesis gel. High hydrothermally stable mesoporous silica was obtained after being aged at 190 o C in the presence of NaF, which endured the hydrothermal treatment in boiling water at least for 10 d or steam treatment at 600 o C for 6 h. The ultra hydrothermal stability could be attributed to its high degree of polymerization of silicate. Furthermore, highly hydrothermal stable mesoporous Fe-SiO 2 has been synthesized, which still remained its mesostructure after being hydrothermally treated at 100 o C for 12 d or steam-treated at 600 o C for 6 h. -- Graphical abstract: Worm-like mesoporous silica and Fe-SiO 2 with high hydrothermal stability have been synthesized using ionic liquid 1-hexadecane-3-methylimidazolium bromide as a template under the assistance of NaF at high temperature. Display Omitted Research highlights: → Increasing aging temperature improved the hydrothermal stability of materials. →Addition of NaF enhanced the polymerization degree of silicates. → Mesoporous SiO 2 and Fe-SiO 2 obtained have remarkable hydrothermal stability.

  16. Hierarchical Mesoporous Zinc-Nickel-Cobalt Ternary Oxide Nanowire Arrays on Nickel Foam as High-Performance Electrodes for Supercapacitors.

    Science.gov (United States)

    Wu, Chun; Cai, Junjie; Zhang, Qiaobao; Zhou, Xiang; Zhu, Ying; Shen, Pei Kang; Zhang, Kaili

    2015-12-09

    Nickel foam supported hierarchical mesoporous Zn-Ni-Co ternary oxide (ZNCO) nanowire arrays are synthesized by a simple two-step approach including a hydrothermal method and subsequent calcination process and directly utilized for supercapacitive investigation for the first time. The nickel foam supported hierarchical mesoporous ZNCO nanowire arrays possess an ultrahigh specific capacitance value of 2481.8 F g(-1) at 1 A g(-1) and excellent rate capability of about 91.9% capacitance retention at 5 A g(-1). More importantly, an asymmetric supercapacitor with a high energy density (35.6 Wh kg(-1)) and remarkable cycle stability performance (94% capacitance retention over 3000 cycles) is assembled successfully by employing the ZNCO electrode as positive electrode and activated carbon as negative electrode. The remarkable electrochemical behaviors demonstrate that the nickel foam supported hierarchical mesoporous ZNCO nanowire array electrodes are highly desirable for application as advanced supercapacitor electrodes.

  17. Highly improved sensibility and selectivity ethanol sensor of mesoporous Fe-doped NiO nanowires

    Science.gov (United States)

    Li, X. Q.; Wei, J. Q.; Xu, J. C.; Jin, H. X.; Jin, D. F.; Peng, X. L.; Hong, B.; Li, J.; Yang, Y. T.; Ge, H. L.; Wang, Xinqing

    2017-12-01

    In this paper, nickel oxides (NiO) and iron (Fe)-doped NiO nanowires (NWs) with the various doping content (from 1 to 9 at%) were synthesized by using SBA-15 templates with the nanocasting method. All samples were synthesized in the same conditions and exhibited the same mesoporous-structures, uniform diameter, and defects. Mesoporous-structures with high surface area created more active sites for the adsorption of oxygen on the surface of all samples, resulting in the smaller surface resistance in air. The impurity energy levels from the donor Fe-doping provided electrons to neutralize the holes of p-type Fe-doped NiO NWs, which greatly enhanced the total resistance. The comparative gas-sensing study between NiO NWs and Fe-doped NiO NWs indicated that the high-valence donor Fe-doping obviously improved the ethanol sensitivity and selectivity for Fe-doped NiO NWs. And Ni0.94Fe0.06O1.03 NWs sensor presented the highest sensitivity of 14.30 toward ethanol gas at 320 °C for the high-valence metal-doping.

  18. Synthesis and characterization of nanometal-ordered mesoporous carbon composites as heterogeneous catalysts for electrooxidation of aniline

    International Nuclear Information System (INIS)

    Duan, Xiaoyue; Chen, Yawen; Liu, Xinyue; Chang, Limin

    2017-01-01

    Highlights: •NM-OMC catalysts were prepared for electrochemical oxidation of aniline. •The oxidation of aniline was studied with NM-OMC catalysts suspended in solution. •The Cu-OMC exhibited the highest catalytic activity for aniline degradation. •The mineralization current efficiency was improved by 2 times with Cu-OMC catalyst. •An electrochemical mineralization pathway of aniline was proposed. -- Abstract: The Cu, Co and Ni nanometal embedded ordered mesoporous carbons (NM-OMCs) were fabricated by a soft-template method using phenol/formaldehyde as carbon source and triblock copolymer F127 as template agent. The morphology, structure, surface physicochemical properties and pore structure of the NM-OMCs were characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and nitrogen adsorption-desorption isotherms. Their potential application to the electrocatalytic degradation of aniline was investigated using electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) and ·OH radicals generation test. Furthermore, the electrochemical oxidation process of aniline was also investigated in the presence of the OMC-based catalyst particles suspended in a Na 2 SO 4 solution using a PbO 2 anode. Results revealed that the NM-OMCs inherited the ordered mesostructure of pristine OMC and the metal nanoparticles (Cu, Co or Ni) were embedded in the carbon framework. The Cu-OMC exhibited significantly higher catalytic activity than OMC and other NM-OMCs for the electrooxidation of aniline. In electrochemical oxidation process of aniline, nearly all of aniline could be degraded after 120 min of electrolysis with Cu-OMC particles as catalyst, while 89%, 92%, and 97% with OMC, Co-OMC and Ni-OMC catalysts, respectively, obviously higher than 76% of electrochemical oxidation without assistance of catalysts. After

  19. Carboxylic acid-grafted mesoporous material and its high catalytic activity in one-pot three-component coupling reaction

    Directory of Open Access Journals (Sweden)

    Ruth Gomes

    2014-11-01

    Full Text Available A new carboxylic acid functionalized mesoporous organic polymer has been synthesized via in situ radical polymerization of divinylbenzene and acrylic acid using a mesoporous silica as a seed during the polymerization process under solvothermal conditions. The mesoporous material MPDVAA-1 has been thoroughly characterized employing powder XRD, solid state 13C cross polarization magic angle spinning-nuclear magnetic resonance, FT-IR spectroscopy, N2 sorption, HR-TEM, and NH3 temperature programmed desorption-thermal conductivity detector (TPD-TCD analysis to understand its porosity, chemical environment, bonding, and surface properties. The mesoporous polymer was used as a catalyst for a three comp onent Biginelli condensation between various aldehydes, β-keto esters, and urea/thioureas to give 3,4-dihydropyrimidine-2(1H-ones. The reactions were carried out under conventional heating as well as solvent-free microwave irradiation of solid components, and in both the cases, the mesoporous polymer MPDVAA-1 proved to be a powerful, robust, and reusable catalyst with high catalytic efficiency.

  20. Mesoporous structured MIPs@CDs fluorescence sensor for highly sensitive detection of TNT.

    Science.gov (United States)

    Xu, Shoufang; Lu, Hongzhi

    2016-11-15

    A facile strategy was developed to prepare mesoporous structured molecularly imprinted polymers capped carbon dots (M-MIPs@CDs) fluorescence sensor for highly sensitive and selective determination of TNT. The strategy using amino-CDs directly as "functional monomer" for imprinting simplify the imprinting process and provide well recognition sites accessibility. The as-prepared M-MIPs@CDs sensor, using periodic mesoporous silica as imprinting matrix, and amino-CDs directly as "functional monomer", exhibited excellent selectivity and sensitivity toward TNT with detection limit of 17nM. The recycling process was sustainable for 10 times without obvious efficiency decrease. The feasibility of the developed method in real samples was successfully evaluated through the analysis of TNT in soil and water samples with satisfactory recoveries of 88.6-95.7%. The method proposed in this work was proved to be a convenient and practical way to prepare high sensitive and selective fluorescence MIPs@CDs sensors. Copyright © 2016 Elsevier B.V. All rights reserved.

  1. Mesoporous high surface area Ce0.9Gd0.1O1.95 synthesized by spray drying

    DEFF Research Database (Denmark)

    Lundberg, Mats; Wang, Hsiang-Jen; Blennow Tullmar, Peter

    2011-01-01

    Mesoporous gadolinium doped cerium dioxide with high surface area was produced by spray drying using Pluronic 123 as surfactant. The powder, when calcined at 400 °C, had a BET surface area of 136 m2 g−1 and was polycrystalline as confirmed by XRD and TEM. XEDS confirmed Ce, Gd and O, as the only......, corresponding to the crystallite size calculated from XRD data. The similar size range of the mesopores and the observed crystallite size indicates that the porosity is partly formed from intergranular mesoporosity. Using the spray drying method of a surfactant assisted liquid precursor solution it can...

  2. Functional Carbon Nanotube/Mesoporous Carbon/MnO2 Hybrid Network for High-Performance Supercapacitors

    Directory of Open Access Journals (Sweden)

    Tao Tao

    2014-01-01

    Full Text Available A functional carbon nanotube/mesoporous carbon/MnO2 hybrid network has been developed successfully through a facile route. The resulting composites exhibited a high specific capacitance of 351 F/g at 1 A g−1, with intriguing charge/discharge rate performance and cycling stability due to a synergistic combination of large surface area and excellent electron-transport capabilities of MnO2 with the good conductivity of the carbon nanotube/mesoporous carbon networks. Such composite shows great potential to be used as electrodes for supercapacitors.

  3. Preparation of Cerium (III) 12-tungstophosphoric acid/ordered mesoporous carbon composite modified electrode and its electrocatalytic properties

    International Nuclear Information System (INIS)

    Liu Lin; Ndamanisha, Jean Chrysostome; Bai Jing; Guo Liping

    2010-01-01

    In this work, a novel structured Cerium (III) 12-tungstophosphoric acid (CePW)/ordered mesoporous carbon (OMC) composite is synthesized. The characterization of the material by the Fourier transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and electrochemical characterization shows that the novel CePW/OMC composite has improved properties based on the combination of CePW and OMC properties. CePW/OMC can be used to modify the glassy carbon (GC) electrode and the CePW/OMC/GC modified electrode shows an enhanced electrocatalytic activity. This property can be applied in the determination of some biomolecules. Especially, the detection and determination of the guanine (G) in the presence of adenine (A) is achieved. The catalytic current of G versus its concentration shows a good linearity with two good linear ranges from 4.0 x 10 -6 to 8.0 x 10 -5 M and from 8.0 x 10 -5 to 1.9 x 10 -3 M (correlation coefficient = 0.999 and 0.996) with a detection limit of 5.7 x 10 -9 M (S/N = 3). The linear range for adenine is 4.0 x 10 -6 -7.0 x 10 -4 M with a detection limit of 7.45 x 10 -8 M. With good stability and reproducibility, the present CePW/OMC/GC modified electrode should be a good model for constructing a novel and promising electrochemical sensing platform for further electrochemical detection of other biomolecules.

  4. Rhodium Nanoparticle-mesoporous Silicon Nanowire Nanohybrids for Hydrogen Peroxide Detection with High Selectivity

    Science.gov (United States)

    Song, Zhiqian; Chang, Hucheng; Zhu, Weiqin; Xu, Chenlong; Feng, Xinjian

    2015-01-01

    Developing nanostructured electrocatalysts, with low overpotential, high selectivity and activity has fundamental and technical importance in many fields. We report here rhodium nanoparticle and mesoporous silicon nanowire (RhNP@mSiNW) hybrids for hydrogen peroxide (H2O2) detection with high electrocatalytic activity and selectivity. By employing electrodes that loaded with RhNP@mSiNW nanohybrids, interference caused from both many electroactive substances and dissolved oxygen were eliminated by electrochemical assaying at an optimal potential of +75 mV. Furthermore, the electrodes exhibited a high detection sensitivity of 0.53 μA/mM and fast response (< 5 s). This high-performance nanohybrid electrocatalyst has great potential for future practical application in various oxidase-base biosensors. PMID:25588953

  5. Effect of ordered mesoporous carbon contact layer on the sensing performance of sputtered RuO2 thin film pH sensor.

    Science.gov (United States)

    Lonsdale, W; Maurya, D K; Wajrak, M; Alameh, K

    2017-03-01

    The effect of contact layer on the pH sensing performance of a sputtered RuO 2 thin film pH sensor is investigated. The response of pH sensors employing RuO 2 thin film electrodes on screen-printed Pt, carbon and ordered mesoporous carbon (OMC) contact layers are measured over a pH range from 4 to 10. Working electrodes with OMC contact layer are found to have Nernstian pH sensitivity (-58.4mV/pH), low short-term drift rate (5.0mV/h), low hysteresis values (1.13mV) and fast reaction times (30s), after only 1h of conditioning. A pH sensor constructed with OMC carbon contact layer displays improved sensing performance compared to Pt and carbon-based counterparts, making this electrode more attractive for applications requiring highly-accurate pH sensing with reduced conditioning time. Copyright © 2016 Elsevier B.V. All rights reserved.

  6. Performance of a Novel Hydrophobic Mesoporous Material for High Temperature Catalytic Oxidation of Naphthalene

    Directory of Open Access Journals (Sweden)

    Guotao Zhao

    2014-01-01

    Full Text Available A high surface area, hydrophobic mesoporous material, MFS, has been successfully synthesized by a hydrothermal synthesis method using a perfluorinated surfactant, SURFLON S-386, as the single template. N2 adsorption and TEM were employed to characterize the pore structure and morphology of MFS. Static water adsorption test indicates that the hydrophobicity of MFS is significantly higher than that of MCM-41. XPS and Py-GC/MS analysis confirmed the existence of perfluoroalkyl groups in MFS which led to its high hydrophobicity. MFS was used as a support for CuO in experiments of catalytic combustion of naphthalene, where it showed a significant advantage over MCM-41 and ZSM-5. SEM was helpful in understanding why CuO-MFS performed so well in the catalytic combustion of naphthalene. Experimental results indicated that MFS was a suitable support for catalytic combustion of large molecular organic compounds, especially for some high temperature catalytic reactions when water vapor was present.

  7. Dissolution enhancement of a model poorly water-soluble drug, atorvastatin, with ordered mesoporous silica: comparison of MSF with SBA-15 as drug carriers.

    Science.gov (United States)

    Maleki, Aziz; Hamidi, Mehrdad

    2016-01-01

    The purpose of this study was to develop mesoporous silica materials incorporated with poorly water-soluble drug atorvastatin calcium (AC) in order to improve drug dissolution, and intended to be orally administrated. A comparison between 2D-hexagonal silica nanostructured SBA-15 and mesocellular siliceous foam (MSF) with continuous 3D pore system on drug release rate was investigated. AC-loaded mesoporous silicas were characterized thorough N2 adsorption-desorption analysis, Fourier transform infrared (FT-IR) spectroscopy, powder X-ray diffraction (PXRD), differential scanning calorimetry (DSC) and dynamic light scattering (DLS). Results demonstrated a successful incorporation of AC into the silica-based hosts. The results taken from the drug release tests were also analyzed using different parameters, namely similarity factor (f2), difference factor (f1), dissolution efficiency (DE%), mean dissolution rate (MDR) and dissolution time (tm%). It confirmed a significant enhancement in the release profile of atorvastatin calcium with SBA-15, and MSF as drug carrier. Moreover, in comparison with SBA-15, MSF showed faster release rate of AC in enzyme-free simulated gastric fluid (pH 1.2). We believed that our findings can help the use of mesoporous silica materials in improving bioavailability of poorly water-soluble drugs.

  8. KF-loaded mesoporous Mg-Fe bi-metal oxides: high performance transesterification catalysts for biodiesel production.

    Science.gov (United States)

    Tao, Guiju; Hua, Zile; Gao, Zhe; Zhu, Yan; Zhu, Yan; Chen, Yu; Shu, Zhu; Zhang, Lingxia; Shi, Jianlin

    2013-09-21

    Using newly developed mesoporous Mg-Fe bi-metal oxides as supports, a novel kind of high performance transesterification catalysts for biodiesel production has been synthesized. More importantly, the impregnation solvent was for the first time found to substantially affect the structures and catalytic performances of the resultant transesterification catalysts.

  9. General strategy for fabricating thoroughly mesoporous nanofibers

    KAUST Repository

    Hou, Huilin; Wang, Lin; Gao, Fengmei; Wei, Guodong; Tang, Bin; Yang, Weiyou; Wu, Tao

    2014-01-01

    mesoporous nanofibers with high purity and uniformity. Here, we report a general, simple and cost-effective strategy, namely, foaming-assisted electrospinning, for producing mesoporous nanofibers with high purity and enhanced specific surface areas. As a

  10. Microwave-induced synthesis of highly dispersed gold nanoparticles within the pore channels of mesoporous silica

    International Nuclear Information System (INIS)

    Gu Jinlou; Fan Wei; Shimojima, Atsushi; Okubo, Tatsuya

    2008-01-01

    Highly dispersed gold nanoparticles have been incorporated into the pore channels of SBA-15 mesoporous silica through a newly developed strategy assisted by microwave radiation (MR). The sizes of gold are effectively controlled attributed to the rapid and homogeneous nucleation, simultaneous propagation and termination of gold precursor by MR. Diol moieties with high dielectric and dielectric loss constants, and hence a high microwave activation, were firstly introduced to the pore channels of SBA-15 by a simple addition reaction between amino group and glycidiol and subsequently served as the reduction centers for gold nanoparticles. Extraction of the entrapped gold from the nanocomposite resulted in milligram quantities of gold nanoparticles with low dispersity. The successful assembly process of diol groups and formation of gold nanoparticles were monitored and tracked by solid-state NMR and UV-vis measurements. Characterization by small angle X-ray diffraction (XRD) and transmission electron microscopy (TEM) indicated that the incorporation of gold nanoparticles would not breakup the structural integrity and long-range periodicity of SBA-15. The gold nanoparticles had a narrow size distribution with diameters in the size range of 5-10 nm through TEM observation. The average particles size is 7.9 nm via calculation by the Scherrer formula and TEM measurements. Nitrogen adsorption and desorption isotherms gave further evidence that the employed method was efficient and gold nanoparticles were successfully incorporated into the pore channels of SBA-15. - Graphical abstract: A facile and novel strategy has been developed to incorporate gold nanoparticles into the pore channels of mesoporous SBA-15 assisted by microwave radiation (MR) with mild reaction condition and rapid reaction speed. Due to the rapid and homogeneous nucleation, simultaneous propagation and termination by MR, the size of gold nanoparticles are effectively controlled

  11. Synthesis of hierarchical mesoporous lithium nickel cobalt manganese oxide spheres with high rate capability for lithium-ion batteries

    Science.gov (United States)

    Tong, Wei; Huang, Yudai; Cai, Yanjun; Guo, Yong; Wang, Xingchao; Jia, Dianzeng; Sun, Zhipeng; Pang, Weikong; Guo, Zaiping; Zong, Jun

    2018-01-01

    Hierarchical mesoporous LiNi1/3Co1/3Mn1/3O2 spheres have been synthesized by urea-assisted solvothermal method with adding Triton X-100. The structure and morphology of the as-prepared materials were analyzed by X-ray diffraction and electron microscope. The results show that the as-prepared samples can be indexed as hexagonal layered structure with hierarchical architecture, and the possible formation mechanism is speculated. When evaluated as cathode material, the hierarchical mesoporous LiNi1/3Co1/3Mn1/3O2 spheres show good electrochemical properties with high initial discharge capacity of 129.9 mAh g-1, and remain the discharge capacity of 95.5 mAh g-1 after 160 cycles at 10C. The excellent electrochemical performance of the as-prepared sample can be attributed to its stable hierarchical mesoporous framework in conjunction with large specific surface, low cation mixing and small particle size. They not only provide a large number of reaction sites for surface or interface reaction, but also shorten the diffusion length of Li+ ions. Meanwhile, the mesoporous spheres composed of nanoparticles can contribute to high rate ability and buffer volume changes during charge/discharge process.

  12. Immobilization of Nafion-ordered mesoporous carbon on a glassy carbon electrode: Application to the detection of epinephrine

    International Nuclear Information System (INIS)

    Zhou Ming; Guo Liping; Hou Ying; Peng Xiaojuan

    2008-01-01

    A stable suspension of ordered mesoporous carbon (OMC) was obtained by dispersing OMC in a solution of Nafion. By coating the suspension onto glassy carbon (GC) electrode, cyclic voltammetry was used to evaluate the electrochemical behaviors of Nafion-OMC-modified GC (Nafion-OMC/GC) electrode in 0.1 mmol L -1 hexaammineruthenium(III) chloride (Ru(NH 3 ) 6 Cl 3 )/0.1 mol L -1 KCl solution, where Nafion-OMC/GC electrode shows a faster electron transfer rate as compared with OMC/GC, Nafion/GC and GC electrodes. Due to the unique properties of Nafion-OMC, an obvious decrease in the overvoltage of the epinephrine (EP) oxidation (ca. 100 mV at pH 4.1 and 115 mV at pH 7.0) as well as a dramatic increase in the peak current (12 times at pH 4.1 and 6 times at pH 7.0) was observed at Nafion-OMC/GC electrode compared to that seen at GC electrode. By combining the advantages of OMC with those of Nafion, the anodic peak of EP and that of ascorbic acid (AA) were separated successfully (by ca. 144-270 mV) in the pH range of 2.0-10.0, which may make Nafion-OMC/GC electrode potential for selective determination of EP in the presence of AA at a broad pH range. As an EP sensor, the EP amperometric response at Nafion-OMC/GC electrode in pH 7.0 PBS is extremely stable, with 99% of the initial activity remaining (compared to 32% at GC surface) after 120 min stirring of 0.20 mmol L -1 EP. And Nafion-OMC/GC electrode can be used to readily detect the physiological concentration of EP at pH 7.0. These make Nafion-OMC/GC electrode potential candidates for stable and efficient electrochemical sensor for the detection of EP. The solubilization of OMC by Nafion may provide a route to more precise manipulation, and functionalization for the construction of OMC-based sensors, as well as allowing OMC to be introduced to biologically relevant systems

  13. Immobilization of Nafion-ordered mesoporous carbon on a glassy carbon electrode: Application to the detection of epinephrine

    Energy Technology Data Exchange (ETDEWEB)

    Zhou Ming [Faculty of Chemistry, Northeast Normal University, Renmin Street 5268, Changchun 130024 (China); Guo Liping [Faculty of Chemistry, Northeast Normal University, Renmin Street 5268, Changchun 130024 (China)], E-mail: guolp078@nenu.edu.cn; Hou Ying; Peng Xiaojuan [Faculty of Chemistry, Northeast Normal University, Renmin Street 5268, Changchun 130024 (China)

    2008-05-01

    A stable suspension of ordered mesoporous carbon (OMC) was obtained by dispersing OMC in a solution of Nafion. By coating the suspension onto glassy carbon (GC) electrode, cyclic voltammetry was used to evaluate the electrochemical behaviors of Nafion-OMC-modified GC (Nafion-OMC/GC) electrode in 0.1 mmol L{sup -1} hexaammineruthenium(III) chloride (Ru(NH{sub 3}){sub 6}Cl{sub 3})/0.1 mol L{sup -1} KCl solution, where Nafion-OMC/GC electrode shows a faster electron transfer rate as compared with OMC/GC, Nafion/GC and GC electrodes. Due to the unique properties of Nafion-OMC, an obvious decrease in the overvoltage of the epinephrine (EP) oxidation (ca. 100 mV at pH 4.1 and 115 mV at pH 7.0) as well as a dramatic increase in the peak current (12 times at pH 4.1 and 6 times at pH 7.0) was observed at Nafion-OMC/GC electrode compared to that seen at GC electrode. By combining the advantages of OMC with those of Nafion, the anodic peak of EP and that of ascorbic acid (AA) were separated successfully (by ca. 144-270 mV) in the pH range of 2.0-10.0, which may make Nafion-OMC/GC electrode potential for selective determination of EP in the presence of AA at a broad pH range. As an EP sensor, the EP amperometric response at Nafion-OMC/GC electrode in pH 7.0 PBS is extremely stable, with 99% of the initial activity remaining (compared to 32% at GC surface) after 120 min stirring of 0.20 mmol L{sup -1} EP. And Nafion-OMC/GC electrode can be used to readily detect the physiological concentration of EP at pH 7.0. These make Nafion-OMC/GC electrode potential candidates for stable and efficient electrochemical sensor for the detection of EP. The solubilization of OMC by Nafion may provide a route to more precise manipulation, and functionalization for the construction of OMC-based sensors, as well as allowing OMC to be introduced to biologically relevant systems.

  14. Mesoporous titanium dioxide (TiO2) with hierarchically 3D dendrimeric architectures: formation mechanism and highly enhanced photocatalytic activity.

    Science.gov (United States)

    Li, Xiao-Yun; Chen, Li-Hua; Rooke, Joanna Claire; Deng, Zhao; Hu, Zhi-Yi; Wang, Shao-Zhuan; Wang, Li; Li, Yu; Krief, Alain; Su, Bao-Lian

    2013-03-15

    Mesoporous TiO(2) with a hierarchically 3D dendrimeric nanostructure comprised of nanoribbon building units has been synthesized via a spontaneous self-formation process from various titanium alkoxides. These hierarchically 3D dendrimeric architectures can be obtained by a very facile, template-free method, by simply dropping a titanium butoxide precursor into methanol solution. The novel configuration of the mesoporous TiO(2) nanostructure in nanoribbon building units yields a high surface area. The calcined samples show significantly enhanced photocatalytic activity and degradation rates owing to the mesoporosity and their improved crystallinity after calcination. Furthermore, the 3D dendrimeric architectures can be preserved after phase transformation from amorphous TiO(2) to anatase or rutile, which occurs during calcination. In addition, the spontaneous self-formation process of mesoporous TiO(2) with hierarchically 3D dendrimeric architectures from the hydrolysis and condensation reaction of titanium butoxide in methanol has been followed by in situ optical microscopy (OM), revealing the secret on the formation of hierarchically 3D dendrimeric nanostructures. Moreover, mesoporous TiO(2) nanostructures with similar hierarchically 3D dendrimeric architectures can also be obtained using other titanium alkoxides. The porosities and nanostructures of the resultant products were characterized by SEM, TEM, XRD, and N(2) adsorption-desorption measurements. The present work provides a facile and reproducible method for the synthesis of novel mesoporous TiO(2) nanoarchitectures, which in turn could herald the fabrication of more efficient photocatalysts. Copyright © 2012 Elsevier Inc. All rights reserved.

  15. Synthesis of highly phosphonic acid functionalized benzene-bridged periodic mesoporous organosilicas for use as efficient dye adsorbents

    International Nuclear Information System (INIS)

    Deka, Juti Rani; Liu, Chia-Ling; Wang, Tzu-Hua; Chang, Wei-Chieh; Kao, Hsien-Ming

    2014-01-01

    Highlights: • Synthesis of highly phosphonic acid functionalized benzene-bridged PMOs. • Phosphonic acid loaded PMOs as adsorbent for cationic and anionic dyes. • Due to electrostatic interaction the adsorbent has high dye adsorption capacity. • π–π stacking interaction between benzene and dye enhances adsorption capacity. • Intraparticle diffusion played a dominant role in the adsorption process. - Abstract: Periodic mesoporous organosilicas (PMOs) with benzene bridging groups in the silica wall were functionalized with a tunable content of phosphonic acid groups. These bifunctional materials were synthesized by co-condensation of two different organosilane precursors, that is, 1,4-bis(triethoxysilyl)benzene (BTEB) and sodium 3-(trihydroxysilyl)propyl methyl phosphate (SPMP), under acidic conditions using nonionic surfactant Brij-S10 as template. The materials exhibited well-ordered mesostructures and were characterized by X-ray diffraction, nitrogen sorption, TEM, TGA, FTIR, and solid-state NMR measurements. The materials thus obtained were employed as adsorbents to remove different types of dyes, for example, cationic dyes methylene blue and phenosafranine, anionic orange II, and amphoteric rhodamine B, from aqueous solutions. The materials exhibited a remarkably high adsorption capacity than activated carbon due to their ordered mesostructures, a large number of phosphonic acid groups, and high surface areas. The adsorption was mainly governed by electrostatic interaction, but also involved π–π stacking interaction as well as hydrogen bonding. The adsorption kinetics can be better fitted by the pseudo-second order model. The adsorption process was controlled by the mechanisms of external mass transfer and intraparticle diffusion. The materials retained more than 97% dye removal efficiency after use for five consecutive cycles

  16. Facile synthesis of mesoporous silica sublayer with hierarchical pore structure on ceramic membrane using anionic polyelectrolyte.

    Science.gov (United States)

    Kang, Taewook; Oh, Seogil; Kim, Honggon; Yi, Jongheop

    2005-06-21

    A facile method for introducing mesoporous silica sublayer onto the surface of a ceramic membrane for use in liquid-phase separation is described. To reduce the electrostatic repulsion between the mesoporous silica sol and the ceramic membrane in highly acidic conditions (pH ceramic membrane, as confirmed by experimental titration data. Consistent with the titration results, the amount of mesoporous silica particles on the surface of the ceramic membrane was low, in the absence of PSS- treatment, whereas mesoporous silica sublayer with hierarchical pore structure was produced, when 1 wt % PSS- was used. The results show that mesoporous silica grows in the confined surface, eventually forming a multistacked surface architecture. The mesoporous silica sublayer contained uniform, ordered (P6 mm) mesopores of ca. 7.5 nm from mesoporous silica as well as macropores ( approximately mum) from interparticle voids, as evidenced by transmission electron microscopy and scanning electron microscopy analyses. The morphologies of the supported mesoporous silica could be manipulated, thus permitting the generation of uniform needlelike forms or uniform spheroid particles by varying the concentration of PSS-.

  17. 无外加酸体系中AlSBA¯15为模板,有序介孔炭材料CMK¯3的合成与表征%Synthesis and characterization of ordered mesoporous carbons CMK_3 produced by tailoring the mesopores of an AlSBA_15 hard template synthesized without acid

    Institute of Scientific and Technical Information of China (English)

    石磊; 徐艳; 邢立淑; 李湘萍; 杨成; 林森

    2014-01-01

    在无外加酸体系中改变晶化温度合成AlSBA¯15介孔材料,并以此为刚性模板,蔗糖为碳源,合成出一系列具有不同孔结构的有序介孔炭材料CMK¯3,系统考察晶化温度对AlSBA¯15和其反相复制结构CMK¯3孔道结构的影响。结果显示在无外加酸合成体系中改变晶化温度可对AlSBA¯15的孔道结构进行有效调控,通过结构复制技术可制备出具有不同结构的CMK¯3。控制刚性模板AlSBA¯15的晶化温度为90益,所得介孔炭材料CMK¯3(CMK¯3(90))结构最佳,除介孔排列高度有序外,还具有高比表面积(1688 m2·g-1)和大孔容(0.95 cm3·g-1)。另外,对CMK¯3的微孔性质与刚性模板孔壁中的次级介孔结构的内在联系进行研究,发现调变刚性模板的晶化温度可以有效改善有序介孔炭材料CMK¯3的结构性质。%Highly ordered mesoporous carbons ( OMCs) designated CMK¯3 were synthesized using mesoporous Al¯SBA¯15 with different textural properties as hard templates and sucrose as a carbon source. Al¯SBA¯15 is an ordered mesoporous alumina¯silica synthesized with a soft template, P123. The effect of the aging temperature for the hard templates on the pore structure of CMK¯3 was investigated. X¯ray diffraction, N2 adsorption and transmission electron microscopy were used to characterize the pore structures of the hard templates and the resultant CMK¯3. Result indicates that CMK¯3 with different pore structures can be obtained by tailor¯ ing the pore structures of the hard templates bysimply controlling the aging temperature in an acid¯free medium. The best CMK¯3 possessed a highly¯ordered pore structure, and a very high BET surface area (1 688 m2 ·g-1 ) and pore volume (0. 95 cm3 ·g-1 ) when the hard template was aged at 90 ℃. The microporous character of the CMK¯3 was related to the thickness of the mesopore wall of the hard templates. The textural characteristics of the resultant CMK¯3 can be improved by simply

  18. Asymmetric mesoporous silica nanoparticles as potent and safe immunoadjuvants provoke high immune responses.

    Science.gov (United States)

    Abbaraju, Prasanna Lakshmi; Jambhrunkar, Manasi; Yang, Yannan; Liu, Yang; Lu, Yao; Yu, Chengzhong

    2018-02-20

    Asymmetric mesoporous silica nanoparticles with a head-tail structure are potent immunoadjuvants for delivering a peptide antigen, generating a higher antibody immune response in mice compared to their symmetric counterparts.

  19. Mesoporous carbon incorporated metal oxide nanomaterials as supercapacitor electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Hao [Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237 (China); School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798 (Singapore); Ma, Jan [School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798 (Singapore); Li, Chunzhong [Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237 (China)

    2012-08-08

    Supercapacitors have attracted huge attention in recent years as they have the potential to satisfy the demand of both huge energy and power density in many advanced technologies. However, poor conductivity and cycling stability remains to be the major challenge for its widespread application. Various strategies have been developed for meeting the ever-increasing energy and power demands in supercapacitors. This Research News article aims to review recent progress in the development of mesoporous carbon incorporated metal oxide nanomaterials, especially metal oxide nanoparticles confined in ordered mesoporous carbon and 1D metal oxides coated with a layer of mesoporous carbon for high-performance supercapacitor applications. In addition, a recent trend in supercapacitor development - hierarchical porous graphitic carbons (HPGC) combining macroporous cores, mesoporous walls, and micropores as an excellent support for metal oxides - is also discussed. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  20. Ferroelectric BiFeO3as an Oxide Dye in Highly Tunable Mesoporous All-Oxide Photovoltaic Heterojunctions

    KAUST Repository

    Wang, Lingfei

    2016-10-12

    As potential photovoltaic materials, transition-metal oxides such as BiFeO3 (BFO) are capable of absorbing a substantial portion of solar light and incorporating ferroic orders into solar cells with enhanced performance. But the photovoltaic application of BFO has been hindered by low energy-conversion efficiency due to poor carrier transport and collection. In this work, a new approach of utilizing BFO as a light-absorbing sensitizer is developed to interface with charge-transporting TiO2 nanoparticles. This mesoporous all-oxide architecture, similar to that of dye-sensitized solar cells, can effectively facilitate the extraction of photocarriers. Under the standard AM1.5 (100 mW cm−2) irradiation, the optimized cell shows an open-circuit voltage of 0.67 V, which can be enhanced to 1.0 V by tailoring the bias history. A fill factor of 55% is achieved, which is much higher than those in previous reports on BFO-based photovoltaic devices. The results provide here a new viable approach toward developing highly tunable and stable photovoltaic devices based on ferroelectric transition-metal oxides.

  1. Ferroelectric BiFeO3 as an Oxide Dye in Highly Tunable Mesoporous All-Oxide Photovoltaic Heterojunctions.

    Science.gov (United States)

    Wang, Lingfei; Ma, He; Chang, Lei; Ma, Chun; Yuan, Guoliang; Wang, Junling; Wu, Tom

    2017-01-01

    As potential photovoltaic materials, transition-metal oxides such as BiFeO 3 (BFO) are capable of absorbing a substantial portion of solar light and incorporating ferroic orders into solar cells with enhanced performance. But the photovoltaic application of BFO has been hindered by low energy-conversion efficiency due to poor carrier transport and collection. In this work, a new approach of utilizing BFO as a light-absorbing sensitizer is developed to interface with charge-transporting TiO 2 nanoparticles. This mesoporous all-oxide architecture, similar to that of dye-sensitized solar cells, can effectively facilitate the extraction of photocarriers. Under the standard AM1.5 (100 mW cm -2 ) irradiation, the optimized cell shows an open-circuit voltage of 0.67 V, which can be enhanced to 1.0 V by tailoring the bias history. A fill factor of 55% is achieved, which is much higher than those in previous reports on BFO-based photovoltaic devices. The results provide here a new viable approach toward developing highly tunable and stable photovoltaic devices based on ferroelectric transition-metal oxides. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. A mesoporous WO3−X/graphene composite as a high-performance Li-ion battery anode

    International Nuclear Information System (INIS)

    Liu, Fei; Kim, Jong Gu; Lee, Chul Wee; Im, Ji Sun

    2014-01-01

    Graphical abstract: The highly flexible and conductive graphene layer can enhance electron transfer, protect metal oxides against disintegration and aggregation and buffer the strain induced by volume expansion during cycles. The mesoporous surface layer provides an open network for Li+ diffusion. - Highlights: • Novel cocktail effects of 2D mesoporous WO 3−X /graphene for lithium ion battery. • New approach for lithium ion battery by easy and unique synthesis method. • Mechanism study with proper data for understanding a reaction on anode surface. - Abstract: A novel mesoporous WO 3−X /graphene composite was developed. This material allowed rapid electron and Li + ion diffusion when used as a Li-ion battery (LIB) anode material. Remarkably, the graphene support protected WO 3−X from changing volume during the electrochemical cycling process; this process generally induces capacity loss. The current work describes a high-performance anode material for LIB that has highly dense WO 3−X , as well as high capacity, rate capability and stability

  3. Highly Sensitive and Selective Hydrogen Gas Sensor Using the Mesoporous SnO2 Modified Layers

    Directory of Open Access Journals (Sweden)

    Niuzi Xue

    2017-10-01

    Full Text Available It is important to improve the sensitivities and selectivities of metal oxide semiconductor (MOS gas sensors when they are used to monitor the state of hydrogen in aerospace industry and electronic field. In this paper, the ordered mesoporous SnO2 (m-SnO2 powders were prepared by sol-gel method, and the morphology and structure were characterized by X-ray diffraction analysis (XRD, transmission electron microscope (TEM and Brunauer–Emmett–Teller (BET. The gas sensors were fabricated using m-SnO2 as the modified layers on the surface of commercial SnO2 (c-SnO2 by screen printing technology, and tested for gas sensing towards ethanol, benzene and hydrogen with operating temperatures ranging from 200 °C to 400 °C. Higher sensitivity was achieved by using the modified m-SnO2 layers on the c-SnO2 gas sensor, and it was found that the S(c/m2 sensor exhibited the highest response (Ra/Rg = 22.2 to 1000 ppm hydrogen at 400 °C. In this paper, the mechanism of the sensitivity and selectivity improvement of the gas sensors is also discussed.

  4. Electrolyte Engineering: Optimizing High-Rate Double-Layer Capacitances of Micropore- and Mesopore-Rich Activated Carbon.

    Science.gov (United States)

    Chen, Ting-Hao; Yang, Cheng-Hsien; Su, Ching-Yuan; Lee, Tai-Chou; Dong, Quan-Feng; Chang, Jeng-Kuei

    2017-09-22

    Various types of electrolyte cations as well as binary cations are used to optimize the capacitive performance of activated carbon (AC) with different pore structures. The high-rate capability of micropore-rich AC, governed by the mobility of desolvated cations, can outperform that of mesopore-rich AC, which essentially depends on the electrolyte conductivity. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Mesoporous MnO2/carbon aerogel composites as promising electrode materials for high-performance supercapacitors.

    Science.gov (United States)

    Li, Gao-Ren; Feng, Zhan-Ping; Ou, Yan-Nan; Wu, Dingcai; Fu, Ruowen; Tong, Ye-Xiang

    2010-02-16

    MnO(2) as one of the most promising candidates for electrochemical supercapacitors has attracted much attention because of its superior electrochemical performance, low cost, and environmentally benign nature. In this Letter, we explored a novel route to prepare mesoporous MnO(2)/carbon aerogel composites by electrochemical deposition assisted by gas bubbles. The products were characterized by energy-dispersive spectrometry (EDS), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The MnO(2) deposits are found to have high purity and have a mesoporous structure that will optimize the electronic and ionic conductivity to minimize the total resistance of the system and thereby maximize the performance characteristics of this material for use in supercapacitor electrodes. The results of nitrogen adsorption-desorption experiments and electrochemical measurements showed that these obtained mesoporous MnO(2)/carbon aerogel composites had a large specific surface area (120 m(2)/g), uniform pore-size distribution (around 5 nm), high specific capacitance (515.5 F/g), and good stability over 1000 cycles, which give these composites potential application as high-performance supercapacitor electrode materials.

  6. Fluorocarbon-bonded magnetic mesoporous microspheres for the analysis of perfluorinated compounds in human serum by high-performance liquid chromatography coupled to tandem mass spectrometry

    International Nuclear Information System (INIS)

    Liu, Xiaodan; Yu, Yingjia; Li, Yan; Zhang, Haiying; Ling, Jin; Sun, Xueni; Feng, Jianan; Duan, Gengli

    2014-01-01

    Highlights: • New SPE method was developed for analysis of PFCs in human serum. • Fluorocarbon-bonded magnetic mesoporous microspheres were used as SPE absorbents. • PFCs in serum were directly extracted without any other pretreatment procedure. • The PFCs-adsorbed microspheres were simply and rapidly isolated by using a magnet. - Abstract: We report herein an extraction method for the analysis of perfluorinated compounds in human serum based on magnetic core–mesoporous shell microspheres with decyl-perfluorinated interior pore-walls (Fe 3 O 4 @mSiO 2 -F 17 ). Thanks to the unique properties of the Fe 3 O 4 @mSiO 2 -F 17 microspheres, macromolecules like proteins could be easily excluded from the mesoporous channels due to size exclusion effect, and perfluorinated compounds (PFCs) in protein-rich biosamples such as serum could thus be directly extracted with the fluorocarbon modified on the channel wall without any other pretreatment procedure. The PFCs adsorbed Fe 3 O 4 @mSiO 2 -F 17 microspheres could then be simply and rapidly isolated by using a magnet, followed by being identified and quantified by LC–MS/MS (high-performance liquid chromatography coupled to tandem mass spectrometry). Five perfluorinatedcarboxylic acids (C6, C8–C11) and perfluorooctane sulfonate (PFOS) were selected as model analytes. In order to achieve the best extraction efficiency, some important factors including the amount of Fe 3 O 4 @mSiO 2 -F 17 microspheres added, adsorption time, type of elution solvent, eluting solvent volume and elution time were investigated. The ranges of the LOD were 0.02–0.05 ng mL −1 for the six PFCs. The recovery of the optimized method varies from 83.13% to 92.42% for human serum samples

  7. High-order finite volume advection

    OpenAIRE

    Shaw, James

    2018-01-01

    The cubicFit advection scheme is limited to second-order convergence because it uses a polynomial reconstruction fitted to point values at cell centres. The highOrderFit advection scheme achieves higher than second order by calculating high-order moments over the mesh geometry.

  8. High-performing mesoporous iron oxalate anodes for lithium-ion batteries.

    Science.gov (United States)

    Ang, Wei An; Gupta, Nutan; Prasanth, Raghavan; Madhavi, Srinivasan

    2012-12-01

    Mesoporous iron oxalate (FeC(2)O(4)) with two distinct morphologies, i.e., cocoon and rod, has been synthesized via a simple, scalable chimie douce precipitation method. The solvent plays a key role in determining the morphology and microstructure of iron oxalate, which are studied by field-emission scanning electron microscopy and high-resolution transmission electron microscopy. Crystallographic characterization of the materials has been carried out by X-ray diffraction and confirmed phase-pure FeC(2)O(4)·2H(2)O formation. The critical dehydration process of FeC(2)O(4)·2H(2)O resulted in anhydrous FeC(2)O(4), and its thermal properties are studied by thermogravimetric analysis. The electrochemical properties of anhydrous FeC(2)O(4) in Li/FeC(2)O(4) cells are evaluated by cyclic voltammetry, galvanostatic charge-discharge cycling, and electrochemical impedance spectroscopy. The studies showed that the initial discharge capacities of anhydrous FeC(2)O(4) cocoons and rods are 1288 and 1326 mA h g(-1), respectively, at 1C rate. Anhydrous FeC(2)O(4) cocoons exhibited stable capacity even at high C rates (11C). The electrochemical performance of anhydrous FeC(2)O(4) is found to be greatly influenced by the number of accessible reaction sites, morphology, and size effects.

  9. Highly-Bioreactive Silica-Based Mesoporous Bioactive Glasses Enriched with Gallium(III

    Directory of Open Access Journals (Sweden)

    Sandra Sanchez-Salcedo

    2018-03-01

    Full Text Available Beneficial effects in bone cell growth and antibacterial action are currently attributed to Ga3+ ions. Thus, they can be used to upgrade mesoporous bioactive glasses (MBGs, investigated for tissue engineering, whenever they released therapeutic amounts of gallium ions to the surrounding medium. Three gallium-enriched MBGs with composition (in mol % xSiO2–yCaO–zP2O5–5Ga2O3, being x = 70, y = 15, z = 10 for Ga_1; x = 80, y = 12, z = 3 for Ga_2; and x = 80, y = 15, z = 0 for Ga_3, were investigated and compared with the gallium-free 80SiO2–15CaO–5P2O5 MBG (B. 29Si and 31P MAS NMR analyses indicated that Ga3+ acts as network modifier in the glass regions with higher polymerization degree and as network former in the zones with high concentration of classical modifiers (Ca2+ ions. Ga_1 and Ga_2 exhibited a quick in vitro bioactive response because they were coated by an apatite-like layer after 1 and 3 days in simulated body fluid. Although we have not conducted biological tests in this paper (cells or bacteria, Ga_1 released high but non-cytotoxic amounts of Ga3+ ions in Todd Hewitt Broth culture medium that were 140 times higher than the IC90 of Pseudomonas aeruginosa bacteria, demonstrating its potential for tissue engineering applications.

  10. Controllable growth of polyaniline nanowire arrays on hierarchical macro/mesoporous graphene foams for high-performance flexible supercapacitors

    International Nuclear Information System (INIS)

    Yu, Pingping; Zhao, Xin; Li, Yingzhi; Zhang, Qinghua

    2017-01-01

    Highlights: • Hierarchical porous graphene foam prepared by templating and embossing method.. • Vertically PANI nanowires aligned on interconnected porous graphene sheets. • The fRGO-F/PANI device exhibited 939 F g"−"1 at 1 A g"−"1. • ED and PD of fRGO-F/PANI device was 20.9 Wh kg"−"1 and 103.2 kW kg"−"1. - Abstract: Free-standing hierarchical macro/mesoporous flexible graphene foam have been constructed by rational intergration ofwell dispersed graphene oxide sheets and amino-modified polystyrene (PS) spheres through a facile “templating and embossing” technique. The three dimensional (3D) macro/mesoporous flexible graphene foam not only inherits the uniform porous structures of graphene foam, but also contains hierarchical macro/mesopores on the struts by sacrificing PS spheres and the activation of KOH, which could providing rapid pathways for ionic and electronic transport to high specific capacitance. Vertically polyaniline (PANI) nanowire arrays are then uniformly deposited onto the hierarchical macro/mesoporous graphene foam(fRGO-F/PANI) by a simple in situ polymerization, which show a high specific capacitance of 939 F g"−"1. Thanks to the synergistic function of 3D bicontinuous hierarchical porous structure of graphene foam and effective immobilization of PANI nanowires on the struts, the assembled symmetric supercapctior with fRGO-F/PANI as electrodes exhibits a maximum energy density and power density of 20.9 Wh kg"−"1 and 103.2 kW kg"−"1, respectively. Moreover, it also displays an excellent cyclic stability with a 88.7% retention after 5000 cycles.

  11. Controllable growth of polyaniline nanowire arrays on hierarchical macro/mesoporous graphene foams for high-performance flexible supercapacitors

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Pingping [State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai 201620 (China); Department of Materials Science, Fudan University, Shanghai 200433 (China); Zhao, Xin, E-mail: xzhao@dhu.edu.cn [State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai 201620 (China); Li, Yingzhi [State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai 201620 (China); Zhang, Qinghua, E-mail: qhzhang@dhu.edu.cn [State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai 201620 (China)

    2017-01-30

    Highlights: • Hierarchical porous graphene foam prepared by templating and embossing method.. • Vertically PANI nanowires aligned on interconnected porous graphene sheets. • The fRGO-F/PANI device exhibited 939 F g{sup −1} at 1 A g{sup −1}. • ED and PD of fRGO-F/PANI device was 20.9 Wh kg{sup −1} and 103.2 kW kg{sup −1}. - Abstract: Free-standing hierarchical macro/mesoporous flexible graphene foam have been constructed by rational intergration ofwell dispersed graphene oxide sheets and amino-modified polystyrene (PS) spheres through a facile “templating and embossing” technique. The three dimensional (3D) macro/mesoporous flexible graphene foam not only inherits the uniform porous structures of graphene foam, but also contains hierarchical macro/mesopores on the struts by sacrificing PS spheres and the activation of KOH, which could providing rapid pathways for ionic and electronic transport to high specific capacitance. Vertically polyaniline (PANI) nanowire arrays are then uniformly deposited onto the hierarchical macro/mesoporous graphene foam(fRGO-F/PANI) by a simple in situ polymerization, which show a high specific capacitance of 939 F g{sup −1}. Thanks to the synergistic function of 3D bicontinuous hierarchical porous structure of graphene foam and effective immobilization of PANI nanowires on the struts, the assembled symmetric supercapctior with fRGO-F/PANI as electrodes exhibits a maximum energy density and power density of 20.9 Wh kg{sup −1} and 103.2 kW kg{sup −1}, respectively. Moreover, it also displays an excellent cyclic stability with a 88.7% retention after 5000 cycles.

  12. High-Order Hamilton's Principle and the Hamilton's Principle of High-Order Lagrangian Function

    International Nuclear Information System (INIS)

    Zhao Hongxia; Ma Shanjun

    2008-01-01

    In this paper, based on the theorem of the high-order velocity energy, integration and variation principle, the high-order Hamilton's principle of general holonomic systems is given. Then, three-order Lagrangian equations and four-order Lagrangian equations are obtained from the high-order Hamilton's principle. Finally, the Hamilton's principle of high-order Lagrangian function is given.

  13. Low-cost route for synthesis of mesoporous silica materials with high silanol groups and their application for Cu(II) removal

    International Nuclear Information System (INIS)

    Wang Yangang; Huang Sujun; Kang Shifei; Zhang Chengli; Li Xi

    2012-01-01

    Graphical abstract: A simple and low-cost route to synthesize mesoporous silica materials with high silanol groups has been demonstrated by means of a sol–gel process using citric acid as the template and acid catalyst, further studies on the adsorption of Cu(II) onto the representative amine-functionalized mesoporous silica showed that it had a high Cu(II) removal efficiency. Highlights: ► A low-cost route to synthesize mesoporous silica with high silanol groups was demonstrated. ► Citric acid as the template and acid catalyst for the reaction of tetraethylorthosilicate. ► Water extraction method was an effective technique to remove template which can be recycled. ► The mesoporous silica with high silanol groups was easily modified by functional groups. ► A high Cu(II) removal efficiency on the amine-functionalized mesoporous silica. - Abstract: We report a simple and low-cost route for the synthesis of mesoporous silica materials with high silanol groups by means of a sol–gel process using citric acid as the template, tetraethylorthosilicate (TEOS) as the silica source under aqueous solution system. The citric acid can directly work as an acid catalyst for the hydrolysis of TEOS besides the function as a pore-forming agent in the synthesis. It was found that by using a water extraction method the citric acid template in as-prepared mesoporous silica composite can be easily removed and a high degree of silanol groups were retained in the mesopores, moreover, the citric acid template in the filtrate can be recycled after being dried. The structural properties of the obtained mesoporous silica materials were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), and nitrogen adsorption–desorption analysis. Furthermore, an adsorption of Cu(II) from aqueous solution on the representative amine-functionalized mesoporous silica was investigated

  14. Rational design of mesoporous metals and related nanomaterials by a soft-template approach.

    Science.gov (United States)

    Yamauchi, Yusuke; Kuroda, Kazuyuki

    2008-04-07

    We review recent developments in the preparation of mesoporous metals and related metal-based nanomaterials. Among the many types of mesoporous materials, mesoporous metals hold promise for a wide range of potential applications, such as in electronic devices, magnetic recording media, and metal catalysts, owing to their metallic frameworks. Mesoporous metals with highly ordered networks and narrow pore-size distributions have traditionally been produced by using mesoporous silica as a hard template. This method involves the formation of an original template followed by deposition of metals within the mesopores and subsequent removal of the template. Another synthetic method is the direct-template approach from lyotropic liquid crystals (LLCs) made of nonionic surfactants at high concentrations. Direct-template synthesis creates a novel avenue for the production of mesoporous metals as well as related metal-based nanomaterials. Many mesoporous metals have been prepared by the chemical or electrochemical reduction of metal salts dissolved in aqueous LLC domains. As a soft template, LLCs are more versatile and therefore more advantageous than hard templates. It is possible to produce various nanostructures (e.g., lamellar, 2D hexagonal (p6mm), and 3D cubic (Ia\\3d)), nanoparticles, and nanotubes simply by controlling the composition of the reaction bath.

  15. Multiscale high-order/low-order (HOLO) algorithms and applications

    International Nuclear Information System (INIS)

    Chacón, L.; Chen, G.; Knoll, D.A.; Newman, C.; Park, H.; Taitano, W.; Willert, J.A.; Womeldorff, G.

    2017-01-01

    We review the state of the art in the formulation, implementation, and performance of so-called high-order/low-order (HOLO) algorithms for challenging multiscale problems. HOLO algorithms attempt to couple one or several high-complexity physical models (the high-order model, HO) with low-complexity ones (the low-order model, LO). The primary goal of HOLO algorithms is to achieve nonlinear convergence between HO and LO components while minimizing memory footprint and managing the computational complexity in a practical manner. Key to the HOLO approach is the use of the LO representations to address temporal stiffness, effectively accelerating the convergence of the HO/LO coupled system. The HOLO approach is broadly underpinned by the concept of nonlinear elimination, which enables segregation of the HO and LO components in ways that can effectively use heterogeneous architectures. The accuracy and efficiency benefits of HOLO algorithms are demonstrated with specific applications to radiation transport, gas dynamics, plasmas (both Eulerian and Lagrangian formulations), and ocean modeling. Across this broad application spectrum, HOLO algorithms achieve significant accuracy improvements at a fraction of the cost compared to conventional approaches. It follows that HOLO algorithms hold significant potential for high-fidelity system scale multiscale simulations leveraging exascale computing.

  16. Multiscale high-order/low-order (HOLO) algorithms and applications

    Energy Technology Data Exchange (ETDEWEB)

    Chacón, L., E-mail: chacon@lanl.gov [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Chen, G.; Knoll, D.A.; Newman, C.; Park, H.; Taitano, W. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Willert, J.A. [Institute for Defense Analyses, Alexandria, VA 22311 (United States); Womeldorff, G. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

    2017-02-01

    We review the state of the art in the formulation, implementation, and performance of so-called high-order/low-order (HOLO) algorithms for challenging multiscale problems. HOLO algorithms attempt to couple one or several high-complexity physical models (the high-order model, HO) with low-complexity ones (the low-order model, LO). The primary goal of HOLO algorithms is to achieve nonlinear convergence between HO and LO components while minimizing memory footprint and managing the computational complexity in a practical manner. Key to the HOLO approach is the use of the LO representations to address temporal stiffness, effectively accelerating the convergence of the HO/LO coupled system. The HOLO approach is broadly underpinned by the concept of nonlinear elimination, which enables segregation of the HO and LO components in ways that can effectively use heterogeneous architectures. The accuracy and efficiency benefits of HOLO algorithms are demonstrated with specific applications to radiation transport, gas dynamics, plasmas (both Eulerian and Lagrangian formulations), and ocean modeling. Across this broad application spectrum, HOLO algorithms achieve significant accuracy improvements at a fraction of the cost compared to conventional approaches. It follows that HOLO algorithms hold significant potential for high-fidelity system scale multiscale simulations leveraging exascale computing.

  17. Electrochemical synthesis of mesoporous Pt-Au binary alloys with tunable compositions for enhancement of electrochemical performance.

    Science.gov (United States)

    Yamauchi, Yusuke; Tonegawa, Akihisa; Komatsu, Masaki; Wang, Hongjing; Wang, Liang; Nemoto, Yoshihiro; Suzuki, Norihiro; Kuroda, Kazuyuki

    2012-03-21

    Mesoporous Pt-Au binary alloys were electrochemically synthesized from lyotropic liquid crystals (LLCs) containing corresponding metal species. Two-dimensional exagonally ordered LLC templates were prepared on conductive substrates from diluted surfactant solutions including water, a nonionic surfactant, ethanol, and metal species by drop-coating. Electrochemical synthesis using such LLC templates enabled the preparation of ordered mesoporous Pt-Au binary alloys without phase segregation. The framework composition in the mesoporous Pt-Au alloy was controlled simply by changing the compositional ratios in the precursor solution. Mesoporous Pt-Au alloys with low Au content exhibited well-ordered 2D hexagonal mesostructures, reflecting those of the original templates. With increasing Au content, however, the mesostructural order gradually decreased, thereby reducing the electrochemically active surface area. Wide-angle X-ray diffraction profiles, X-ray photoelectron spectra, and elemental mapping showed that both Pt and Au were atomically distributed in the frameworks. The electrochemical stability of mesoporous Pt-Au alloys toward methanol oxidation was highly improved relative to that of nonporous Pt and mesoporous Pt films, suggesting that mesoporous Pt-Au alloy films are potentially applicable as electrocatalysts for direct methanol fuel cells. Also, mesoporous Pt-Au alloy electrodes showed a highly sensitive amperometric response for glucose molecules, which will be useful in next-generation enzyme-free glucose sensors.

  18. Antisolvent Precipitation for the Synthesis of Monodisperse Mesoporous Niobium Oxide Spheres as Highly Effective Solid Acid Catalysts

    KAUST Repository

    Li, Cheng Chao; Dou, Jian; Chen, Luwei; Lin, Jianyi; Zeng, Hua Chun

    2012-01-01

    We have developed a low-cost reaction protocol to synthesize mesoporous Nb 2O 5-based solid acid catalysts with external shape control. In the synthesis, monodisperse glycolated niobium oxide spheres (GNOS) were prepared by means of a simple antisolvent precipitation approach and subsequently converted to mesoporous niobium oxide spheres (MNOS) with a large surface area of 312m 2g -1 by means of the hydrothermal treatment. The antisolvent acetone used to obtain GNOS was recovered through distillation at high purity. The obtained mesoporous MNOS were functionalized further with sulfate anions at different temperatures or incorporated with tungstophosphoric acid to obtain recyclable solid acid catalysts. These MNOS-based catalysts showed excellent performance in a wide range of acid-catalyzed reactions, such as Friedel-Crafts alkylation, esterification, and hydrolysis of acetates. As they are monodisperse spheres with diameters in the submicrometer range, the catalysts can be easily separated and reused. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Antisolvent Precipitation for the Synthesis of Monodisperse Mesoporous Niobium Oxide Spheres as Highly Effective Solid Acid Catalysts

    KAUST Repository

    Li, Cheng Chao

    2012-03-20

    We have developed a low-cost reaction protocol to synthesize mesoporous Nb 2O 5-based solid acid catalysts with external shape control. In the synthesis, monodisperse glycolated niobium oxide spheres (GNOS) were prepared by means of a simple antisolvent precipitation approach and subsequently converted to mesoporous niobium oxide spheres (MNOS) with a large surface area of 312m 2g -1 by means of the hydrothermal treatment. The antisolvent acetone used to obtain GNOS was recovered through distillation at high purity. The obtained mesoporous MNOS were functionalized further with sulfate anions at different temperatures or incorporated with tungstophosphoric acid to obtain recyclable solid acid catalysts. These MNOS-based catalysts showed excellent performance in a wide range of acid-catalyzed reactions, such as Friedel-Crafts alkylation, esterification, and hydrolysis of acetates. As they are monodisperse spheres with diameters in the submicrometer range, the catalysts can be easily separated and reused. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Iron oxide nanoparticles stabilized inside highly ordered ...

    Indian Academy of Sciences (India)

    Nanosized iron oxide, a moderately large band-gap semiconductor and an essential component of optoelectrical and magnetic devices, has been prepared successfully inside the restricted internal pores of mesoporous silica material through in-situ reduction during impregnation. The samples were characterized by ...

  1. Mesoporous polyaniline film on ultra-thin graphene sheets for high performance supercapacitors

    Science.gov (United States)

    Wang, Qian; Yan, Jun; Fan, Zhuangjun; Wei, Tong; Zhang, Milin; Jing, Xiaoyan

    2014-02-01

    A facile approach has been developed to fabricate mesoporous PANI film on ultra-thin graphene nanosheet (G-mPANI) hybrid by in situ polymerization using graphene-mesoporous silica composite as template. Due to its mesoporous structure, over-all conductive network, G-mPANI electrode displays a specific capacitance of 749 F g-1 at 0.5 A g-1 with excellent rate capability (remains 73% even at 5.0 A g-1), much higher than that of pristine PANI electrode (315 F g-1 at 0.5 A g-1, 39% retention at 5.0 A g-1) in 1 mol L-1 H2SO4 aqueous solution. More interestingly, the G-mPANI hybrid can maintain 88% of its initial capacitance compared to 45% for pristine PANI after 1000 cycles, suggesting a superior electrochemical cyclic stability.

  2. "Bricks and mortar" self-assembly approach to graphitic mesoporous carbon nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Fulvio, P. F.; Mayes, R.; Wang, X. Q.; Mahurin, S., M.; Bauer, J. C.; Presser, V.; McDonough, J.; Gogotsi, Y.; Dai, S.

    2011-04-20

    Mesoporous carbon materials do not have sufficient ordering at the atomic scale to exhibit good electronic conductivity. To date, mesoporous carbons having uniform mesopores and high surface areas have been prepared from partially-graphitizable precursors in the presence of templates. High temperature thermal treatments above 2000 °C, which are usually required to increase conductivity, result in a partial or total collapse of the mesoporous structures and reduced surface areas induced by growth of graphitic domains, limiting their applications in electric double layer capacitors and lithium-ion batteries. In this work, we successfully implemented a “brick-and-mortar” approach to obtain ordered graphitic mesoporous carbon nanocomposites with tunable mesopore sizes below 850 °C without using graphitization catalysts or high temperature thermal treatments. Phenolic resin-based mesoporous carbons act as mortar to highly conductive carbon blacks and carbon onions (bricks). The capacitance and resistivity of final materials can be tailored by changing the mortar to brick ratios.

  3. Highly mesoporous single-crystalline zeolite beta synthesized using a nonsurfactant cationic polymer as a dual-function template

    KAUST Repository

    Zhu, Jie; Zhu, Yihan; Zhu, Liangkui; Rigutto, Marcello S.; Van Der Made, Alexander W.; Yang, Chengguang; Pan, Shuxiang; Wang, Liang; Zhu, Longfeng; Jin, Yinying; Sun, Qi; Wu, Qinming; Meng, Xiangju; Zhang, Daliang; Han, Yu; Li, Jixue; Chu, Yueying; Zheng, Anmin; Qiu, Shilun; Zheng, Xiaoming; Xiao, Fengshou

    2014-01-01

    Mesoporous zeolites are useful solid catalysts for conversion of bulky molecules because they offer fast mass transfer along with size and shape selectivity. We report here the successful synthesis of mesoporous aluminosilicate zeolite Beta from a

  4. High-Order Frequency-Locked Loops

    DEFF Research Database (Denmark)

    Golestan, Saeed; Guerrero, Josep M.; Quintero, Juan Carlos Vasquez

    2017-01-01

    In very recent years, some attempts for designing high-order frequency-locked loops (FLLs) have been made. Nevertheless, the advantages and disadvantages of these structures, particularly in comparison with a standard FLL and high-order phase-locked loops (PLLs), are rather unclear. This lack...... study, and its small-signal modeling, stability analysis, and parameter tuning are presented. Finally, to gain insight about advantages and disadvantages of high-order FLLs, a theoretical and experimental performance comparison between the designed second-order FLL and a standard FLL (first-order FLL...

  5. Mesoporous layers of TiO2 as highly efficient photocatalysts for the purification of air

    Czech Academy of Sciences Publication Activity Database

    Kalousek, Vít; Tschirch, J.; Bahnemann, D.; Rathouský, Jiří

    2008-01-01

    Roč. 44, 4-5 (2008), s. 506-513 ISSN 0749-6036 R&D Projects: GA MŠk 1M0577 Institutional research plan: CEZ:AV0Z40400503 Keywords : TiO2 * mesoporous film * evaporation induced self-assembly Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.211, year: 2008

  6. Template synthesis and characterization of nanostructured hierarchical mesoporous ribbon-like NiO as high performance electrode material for supercapacitor

    International Nuclear Information System (INIS)

    Yao, Mingming; Hu, Zhonghua; Xu, Zijie; Liu, Yafei; Liu, Peipei; Zhang, Qiang

    2015-01-01

    The ribbon-like NiO was synthesized by a hard-template method combining the calcination, using mesoporous carbon as a hard templat and guanidine hydrochloride as precipitant of weak base, respectively. The nanostructured hierarchical mesoporous ribbon-like NiO exhibits the high specific capacitance of 1260 F g −1 at the current density of 1 A g −1 , and 95% capacity retention at a current density of 10 A g −1 in a testing range of 5000 cycles. - Highlights: • Ribbon-like NiO was prepared by using mesoporous carbon as a hard template. • Typical ribbon-like NiO possesses the hierarchical mesoporous nanostructure. • High specific capacitance of 1260 F g −1 is obtained at a current density of 1 A g −1 . • Excellent electrochemical stability of 95% after 5000 charge–discharge cycles. - Abstract: In this paper, nanostructured hierarchical mesoporous ribbon-like NiO was synthesized by a hard-template method combining the calcination process. Nickel sulfate hexahydrate, guanidine hydrochloride and mesoporous carbon were used as nickel precursors, precipitant of weak base and template, respectively. The resultant NiO samples were characterized by Raman spectroscopy, energy dispersive spectrometer, X-ray diffraction, N 2 adsorption and desorption, scanning electron microscopy and transmission electron microscopy. The electrochemical performances were evaluated by cyclic voltammetry (CV), cyclic chronopotentiometry (CP) and electrochemical impedance spectroscopy (EIS) in 6 M KOH solution. The typical hierarchical mesoporous ribbon-like NiO shows a good electrochemical performance: a high specific capacitance of 1260 F g −1 at 1 A g −1 , 748 F g −1 at high current density of 20 A g −1 and 95% capacity retention at a current density of 10 A g −1 in a testing range of 5000 cycles

  7. Facile synthesis of mesoporous NiFe2O4/CNTs nanocomposite cathode material for high performance asymmetric pseudocapacitors

    Science.gov (United States)

    Kumar, Nagesh; Kumar, Amit; Huang, Guan-Min; Wu, Wen-Wei; Tseng, Tseung Yuen

    2018-03-01

    Morphology and synergistic effect of constituents are the two very important factors that greatly influence the physical, chemical and electrochemical properties of a composite material. In the present work, we report the enhanced electrochemical performance of mesoporous NiFe2O4 and multiwall carbon nanotubes (MWCNTs) nanocomposites synthesized via hexamethylene tetramine (HMT) assisted one-pot hydrothermal approach. The synthesized cubic phase spinel NiFe2O4 nanomaterial possesses high specific surface area (148 m2g-1) with narrow mesopore size distribution. The effect of MWCNTs addition on the electrochemical performance of nanocomposite has been probed thoroughly in a normal three electrode configuration using 2 M KOH electrolyte at room temperature. Experimental results show that the addition of mere 5 mg MWCNTs into fixed NiFe2O4 precursors amount enhances the specific capacitance up to 1291 F g-1 at 1 A g-1, which is the highest reported value for NiFe2O4 nanocomposites so far. NiFe2O4/CNT nanocomposite exhibits small relaxation time constant (1.5 ms), good rate capability and capacitance retention of 81% over 500 charge-discharge cycles. This excellent performance can be assigned to high surface area, mesoporous structure of NiFe2O4 and conducting network formed by MWCNTs in the composite. Further, to evaluate the device performance of the composite, an asymmetric pseudocapacitor has been designed using NiFe2O4/CNT nanocomposite as a positive and N-doped graphene as a negative electrode material, respectively. Our designed asymmetric pseudocapacitor gives maximum energy density of 23 W h kg-1 at power density of 872 W kg-1. These promising results assert the potential of synthesized nanocomposite in the development of efficient practical high-capacitive energy storage devices.

  8. Crystalline mesoporous tungsten oxide nanoplate monoliths synthesized by directed soft template method for highly sensitive NO{sub 2} gas sensor applications

    Energy Technology Data Exchange (ETDEWEB)

    Hoa, Nguyen Duc, E-mail: ndhoa@itims.edu.vn [International Training Institute for Materials Science (ITIMS), Hanoi University of Science and Technology (HUST) (Viet Nam); Duy, Nguyen Van [International Training Institute for Materials Science (ITIMS), Hanoi University of Science and Technology (HUST) (Viet Nam); Hieu, Nguyen Van, E-mail: hieu@itims.edu.vn [International Training Institute for Materials Science (ITIMS), Hanoi University of Science and Technology (HUST) (Viet Nam)

    2013-02-15

    Graphical abstract: Display Omitted Highlights: ► Mesoporous WO{sub 3} nanoplate monoliths were obtained by direct templating synthesis. ► Enable effective accession of the analytic molecules for the sensor applications. ► The WO{sub 3} sensor exhibited a high performance to NO{sub 2} gas at low temperature. -- Abstract: Controllable synthesis of nanostructured metal oxide semiconductors with nanocrystalline size, porous structure, and large specific surface area is one of the key issues for effective gas sensor applications. In this study, crystalline mesoporous tungsten oxide nanoplate-like monoliths with high specific surface areas were obtained through instant direct-templating synthesis for highly sensitive nitrogen dioxide (NO{sub 2}) sensor applications. The copolymer soft template was converted into a solid carbon framework by heat treatment in an inert gas prior to calcinations in air to sustain the mesoporous structure of tungsten oxide. The multidirectional mesoporous structures of tungsten oxide with small crystalline size, large specific surface area, and superior physical characteristics enabled the rapid and effective accession of analytic gas molecules. As a result, the sensor response was enhanced and the response and recovery times were reduced, in which the mesoporous tungsten oxide based gas sensor exhibited a superior response of 21,155% to 5 ppm NO{sub 2}. In addition, the developed sensor exhibited selective detection of low NO{sub 2} concentration in ammonia and ethanol at a low temperature of approximately 150 °C.

  9. Sensors based on mesoporous SnO{sub 2}-CuWO{sub 4} with high selective sensitivity to H{sub 2}S at low operating temperature

    Energy Technology Data Exchange (ETDEWEB)

    Stanoiu, Adelina; Simion, Cristian E. [National Institute of Materials Physics, Atomistilor 405A, P.O. Box MG-7, 077125 Bucharest, Măgurele (Romania); Calderon-Moreno, Jose Maria; Osiceanu, Petre [“Ilie Murgulescu” Institute of Physical Chemistry, Romanian Academy, Surface Chemistry and Catalysis Laboratory, Spl. Independentei 202, 060021, Bucharest (Romania); Florea, Mihaela [University of Bucharest, Faculty of Chemistry, Department of Organic Chemistry, Biochemistry and Catalysis, B-dul Regina Elisabeta 4-12, Bucharest (Romania); National Institute of Materials Physics, Atomistilor 405A, P.O. Box MG-7, 077125 Bucharest, Măgurele (Romania); Teodorescu, Valentin S. [National Institute of Materials Physics, Atomistilor 405A, P.O. Box MG-7, 077125 Bucharest, Măgurele (Romania); Somacescu, Simona, E-mail: somacescu.simona@gmail.com [“Ilie Murgulescu” Institute of Physical Chemistry, Romanian Academy, Surface Chemistry and Catalysis Laboratory, Spl. Independentei 202, 060021, Bucharest (Romania)

    2017-06-05

    Highlights: • Mesoporous SnO{sub 2}-CuWO{sub 4} obtained by an inexpensive synthesis route. • Powders characterization performed by a variety of complementary techniques. • SnO{sub 2}-CuWO{sub 4} layers with high selective sensitivity to H{sub 2}S. • Low operating temperature and relative humidity influences. - Abstract: Development of new sensitive materials by different synthesis routes in order to emphasize the sensing properties for hazardous H{sub 2}S detection is one of a nowadays challenge in the field of gas sensors. In this study we obtained mesoporous SnO{sub 2}-CuWO{sub 4} with selective sensitivity to H{sub 2}S by an inexpensive synthesis route with low environmental pollution level, using tripropylamine (TPA) as template and polyvinylpyrrolidone (PVP) as dispersant/stabilizer. In order to bring insights about the intrinsic properties, the powders were characterized by means of a variety of complementary techniques such as: X-Ray Diffraction, XRD; Transmission Electron Microscopy, TEM; High Resolution TEM, HRTEM; Raman Spectroscopy, RS; Porosity Analysis by N{sub 2} adsorption/desorption, BET; Scanning Electron Microscopy, SEM and X-ray Photoelectron Spectroscopy, XPS. The sensors were fabricated by powders deposition via screen-printing technique onto planar commercial Al{sub 2}O{sub 3} substrates. The sensor signals towards H{sub 2}S exposure at low operating temperature (100 °C) reaches values from 10{sup 5} (for SnWCu600) to 10{sup 6} (for SnWCu800) over the full range of concentrations (5–30 ppm). The recovery processes were induced by a short temperature trigger of 500 °C. The selective sensitivity was underlined with respect to the H{sub 2}S, relative to other potential pollutants and relative humidity (10–70% RH).

  10. Mesoporous Zn2SnO4 as effective electron transport materials for high-performance perovskite solar cells

    International Nuclear Information System (INIS)

    Bao, Sha; Wu, Jihuai; He, Xin; Tu, Yongguang; Wang, Shibo; Huang, Miaoliang; Lan, Zhang

    2017-01-01

    Highlights: •Large grain and mesoporous Zn 2 SnO 4 are synthesized by a facile hydrothermal method. •Perovskite device with Zn 2 SnO 4 electron transport layer get efficiency of 17.21%. •While the device with TiO 2 electron transport layer obtain an efficiency of 14.83%. •Superior photovoltaic performance stems from the intrinsic characteristics of Zn 2 SnO 4 . -- Abstract: Electron transport layer with higher carrier mobility and suitable band gap structure plays a significant role in determining the photovoltaic performance of perovskite solar cells (PSCs). Here, we report a synthesis of high crystalline zinc stannate (Zn 2 SnO 4 ) by a facile hydrothermal method. The as-synthesized Zn 2 SnO 4 possesses particle size of 20 nm, large surface area, mesoporous hierarchical structure, and can be used as a promising electron-transport materials to replace the conventional mesoporous TiO 2 material. A perovskite solar cell with structure of FTO/blocking layer/Zn 2 SnO 4 /CH 3 NH 3 PbI 3 /Spiro-OMeOTAD/Au is fabricated, and the preparation condition is optimized. The champion device based on Zn 2 SnO 4 electron transport material achieves a power conversion efficiency of 17.21%, while the device based on TiO 2 electron transport material gets an efficiency of 14.83% under the same experimental conditions. The results render Zn 2 SnO 4 an effective candidate as electron transport material for high performance perovskite solar cells and other devices.

  11. Encapsulation of valproic acid and sodic phenytoin in ordered mesoporous SiO 2 solids for the treatment of temporal lobe epilepsy

    Science.gov (United States)

    López, T.; Basaldella, E. I.; Ojeda, M. L.; Manjarrez, J.; Alexander-Katz, R.

    2006-10-01

    Temporal lobe epilepsy is one of the most frequent types of human neurological diseases, and a variety of surgical procedures have been developed for the treatment of intractable cases. An alternative is the use of drug-containing reservoirs based on nanostructured materials of controlled pore sizes in order to deliver the drug without causing secondary effects. Ordered SiO 2 nanostructures were developed as drug reservoirs. The latter were prepared by the sol-gel process using tetraethyl orthosilicate TEOS as precursor to form the "sol" and P123 surfactant as the organic structure-directing agent. In addition to the nontoxic nature of amorphous silica, uniform and tunable pore sizes between 2.5 and 30 nm can be obtained in this way. The aim of this study is to investigate the potential of these materials for the storage and release of drugs in the brain. For that, we loaded valproic acid (VH) and sodic phenytoin (PH) molecules into an ordered mesoporous SiO 2 by impregnation and characterized the drug impregnated SiO 2 by standard physical and spectroscopic techniques to identify the parameters necessary to improve the capacity and quality of the reservoirs. Finally, a study of neurohistopathology of the effects of these reservoirs on brain tissue is presented.

  12. High-performance carbon nanotube-implanted mesoporous carbon spheres for supercapacitors with low series resistance

    Energy Technology Data Exchange (ETDEWEB)

    Yi, Bin [College of Materials Science and Engineering, Hunan University, Changsha 410082 (China); Chen, Xiaohua, E-mail: hudacxh62@yahoo.com.cn [College of Materials Science and Engineering, Hunan University, Changsha 410082 (China); Guo, Kaimin [College of Physics and Electronic Science, Changsha University of Science and Technology (China); Xu, Longshan [Department of Mechanical Engineering, Xiamen University of Technology, Xiamen 361024 (China); Chen, Chuansheng [College of Physics and Electronic Science, Changsha University of Science and Technology (China); Yan, Haimei; Chen, Jianghua [College of Materials Science and Engineering, Hunan University, Changsha 410082 (China)

    2011-11-15

    Research highlights: {yields} CNTs-implanted porous carbon spheres are prepared by using gelatin as soft template. {yields} Homogeneously distributed CNTs form a well-develop network in carbon spheres. {yields} CNTs act as a reinforcing backbone assisting the formation of pore structure. {yields} CNTs improve electrical conductivity and specific capacitance of supercapacitor. -- Abstract: Carbon nanotube-implanted mesoporous carbon spheres were prepared by an easy polymerization-induced colloid aggregation method using gelatin as a soft template. Scanning electron microscopy, transmission electron microscopy and nitrogen adsorption-desorption measurements reveal that the materials are mesoporous carbon spheres, with a diameter of {approx}0.5-1.0 {mu}m, a specific surface area of 284 m{sup 2}/g and average pore size of 3.9 nm. Using the carbon nanotube-implanted mesoporous carbon spheres as electrode material for supercapacitors in an aqueous electrolyte solution, a low equivalent series resistance of 0.83 {Omega} cm{sup 2} and a maximum specific capacitance of 189 F/g with a measured power density of 8.7 kW/kg at energy density of 6.6 Wh/kg are obtained.

  13. High Rate Performance Nanocomposite Electrode of Mesoporous Manganese Dioxide/Silver Nanowires in KI Electrolytes

    Directory of Open Access Journals (Sweden)

    Yanhua Jiang

    2015-10-01

    Full Text Available In recent years, manganese dioxide has become a research hotspot as an electrode material because of its low price. However, it has also become an obstacle to industrialization due to its low ratio of capacitance and the low rate performance which is caused by the poor electrical conductivity. In this study, a KI solution with electrochemical activity was innovatively applied to the electrolyte, and we systematically investigated the rate performance of the mesoporous manganese dioxide and the composite electrode with silver nanowires in supercapacitors. The results showed that when mesoporous manganese dioxide and mesoporous manganese dioxide/silver nanowires composite were used as electrodes, the strength of the current was amplified five times (from 0.1 to 0.5 A/g, the remaining rates of specific capacitance were 95% (from 205.5 down to 197.1 F/g and 92% (from 208.1 down to 191.7 F/g in the KI electrolyte, and the rate performance was much higher than which in an Na2SO4 electrolyte with a remaining rate of 25% (from 200.3 down to 49.1 F/g and 60% (from 187.2 down to 113.1 F/g. The morphology and detail structure were investigated by Scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectrometry and Nitrogen adsorption-desorption isotherms. The electrochemical performance was assessed by cyclic voltammograms, galvanostatic charge/discharge and electrochemical impedance spectroscopy.

  14. High-order passive photonic temporal integrators.

    Science.gov (United States)

    Asghari, Mohammad H; Wang, Chao; Yao, Jianping; Azaña, José

    2010-04-15

    We experimentally demonstrate, for the first time to our knowledge, an ultrafast photonic high-order (second-order) complex-field temporal integrator. The demonstrated device uses a single apodized uniform-period fiber Bragg grating (FBG), and it is based on a general FBG design approach for implementing optimized arbitrary-order photonic passive temporal integrators. Using this same design approach, we also fabricate and test a first-order passive temporal integrator offering an energetic-efficiency improvement of more than 1 order of magnitude as compared with previously reported passive first-order temporal integrators. Accurate and efficient first- and second-order temporal integrations of ultrafast complex-field optical signals (with temporal features as fast as approximately 2.5ps) are successfully demonstrated using the fabricated FBG devices.

  15. Mesoporous Co3O4 nanosheets-3D graphene networks hybrid materials for high-performance lithium ion batteries

    International Nuclear Information System (INIS)

    Sun, Hongyu; Liu, Yanguo; Yu, Yanlong; Ahmad, Mashkoor; Nan, Ding; Zhu, Jing

    2014-01-01

    Graphical abstract: - Highlights: • The mesoporous Co 3 O 4 nanosheets-3D graphene networks have been found to display better LIB performance as compare with Co 3 O 4 /CNT and Co 3 O 4 structures. • Electrochemical impedance spectroscopy shows that the addition of 3DGN largely enhanced the electrochemical activity of Co 3 O 4 during the cycling processes. • The large specific surface area and porous nature of the Co 3 O 4 nanosheets are very convenient and accessible for electrolyte diffusion and intercalation of Li + ions into the active phases. - Abstract: Mesoporous Co 3 O 4 nanosheets-3D graphene networks (3DGN) hybrid materials have been synthesized by combining chemical vapor deposition (CVD) and hydrothermal method and investigated as anode materials for Li-ion batteries (LIBs). Microscopic characterizations have been performed to confirm the 3DGN and mesoporous Co 3 O 4 nanostructures. The specific surface area and pore size of the hybrid structures have been found ∼ 34.5 m 2 g −1 and ∼ 3.8 nm respectively. It has been found that the Co 3 O 4 /3DGNs composite displays better LIB performance with enhanced reversible capacity, good cyclic performance and rate capability as compare with Co 3 O 4 /CNT and Co 3 O 4 structures. Electrochemical impedance spectroscopy (EIS) results show that the addition of 3DGN not only preserves high conductivity of the composite electrode, but also largely enhanced the electrochemical activity of Co 3 O 4 during the cycling processes. The improved electrochemical performance is considered due to the addition of 3DGNs which prevent the cracking of electrode. In addition, the large specific surface area and porous nature of the Co 3 O 4 nanosheets are also very convenient and accessible for electrolyte diffusion and intercalation of Li + ions into the active phases. Therefore, this combination can be considered to be an attractive candidate as an anode material for LIBs

  16. High-order beam optics - an overview

    International Nuclear Information System (INIS)

    Heighway, E.A.

    1989-01-01

    Beam-transport codes have been around for as long as thirty years and high order codes, second-order at least, for close to twenty years. Before this period of design-code development, there was considerable high-order treatment, but it was almost entirely analytical. History has a way of repeating itself, and the current excitement in the field of high-order optics is based on the application of Lie algebra and the so-called differential algebra to beam-transport codes, both of which are highly analytical in foundation. The author will describe some of the main design tools available today, giving a little of their history, and will conclude by trying to convey some of the excitement in the field through a brief description of Lie and differential algebra. 30 refs., 7 figs., 1 tab

  17. Bioinspired Nanocomposite Hydrogels with Highly Ordered Structures.

    Science.gov (United States)

    Zhao, Ziguang; Fang, Ruochen; Rong, Qinfeng; Liu, Mingjie

    2017-12-01

    In the human body, many soft tissues with hierarchically ordered composite structures, such as cartilage, skeletal muscle, the corneas, and blood vessels, exhibit highly anisotropic mechanical strength and functionality to adapt to complex environments. In artificial soft materials, hydrogels are analogous to these biological soft tissues due to their "soft and wet" properties, their biocompatibility, and their elastic performance. However, conventional hydrogel materials with unordered homogeneous structures inevitably lack high mechanical properties and anisotropic functional performances; thus, their further application is limited. Inspired by biological soft tissues with well-ordered structures, researchers have increasingly investigated highly ordered nanocomposite hydrogels as functional biological engineering soft materials with unique mechanical, optical, and biological properties. These hydrogels incorporate long-range ordered nanocomposite structures within hydrogel network matrixes. Here, the critical design criteria and the state-of-the-art fabrication strategies of nanocomposite hydrogels with highly ordered structures are systemically reviewed. Then, recent progress in applications in the fields of soft actuators, tissue engineering, and sensors is highlighted. The future development and prospective application of highly ordered nanocomposite hydrogels are also discussed. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Hydrothermal stability investigation of micro- and mesoporous silica containing long-range ordered cobalt oxide clusters by XAS.

    Science.gov (United States)

    Liu, Liang; Wang, David K; Kappen, Peter; Martens, Dana L; Smart, Simon; Diniz da Costa, João C

    2015-07-15

    This work investigates the hydrothermal stability of cobalt doped silica materials with different Co/Si molar ratios (0, 0.05, 0.10, and 0.25). The resultant materials were characterized by N2 sorption and chemical structures by Raman and X-ray absorption spectroscopy before and after a harsh hydrothermal exposure (550 °C, 75 mol% vapour and 40 h). The cobalt silica materials showed a lower surface area loss from 48% to 12% with increasing Co/Si molar ratio from 0.05 to 0.25 and relatively maintaining their pore size distribution, while pure silica exhibited significant surface area reduction (80%) and pore size broadening. For low cobalt loading sample (Co/Si = 0.05), the cobalt was highly dispersed in the silica network in a tetrahedral coordination with oxygen and a small proportion of Co-Co interaction in the second shell. Long range order Co3O4 was observed when Co/Si molar ratio increased to 0.10 and 0.25. The hydrothermal exposure did not affect the local cobalt environments and no cobalt-silicon interaction was observed by X-ray absorption spectroscopy. The hydrothermal stability of the silica matrix was attributed to the physical barrier of cobalt oxide in opposing densification and silica mobility under harsh hydrothermal conditions.

  19. Kinetically Controlled Synthesis of Pt-Based One-Dimensional Hierarchically Porous Nanostructures with Large Mesopores as Highly Efficient ORR Catalysts.

    Science.gov (United States)

    Fu, Shaofang; Zhu, Chengzhou; Song, Junhua; Engelhard, Mark H; Xia, Haibing; Du, Dan; Lin, Yuehe

    2016-12-28

    Rational design and construction of Pt-based porous nanostructures with large mesopores have triggered significant considerations because of their high surface area and more efficient mass transport. Hydrochloric acid-induced kinetically controlled reduction of metal precursors in the presence of soft template F-127 and hard template tellurium nanowires has been successfully demonstrated to construct one-dimensional hierarchical porous PtCu alloy nanostructures with large mesopores. Moreover, the electrochemical experiments demonstrated that the PtCu hierarchically porous nanostructures synthesized under optimized conditions exhibit enhanced electrocatalytic performance for oxygen reduction reaction in acid media.

  20. Kinetically Controlled Synthesis of Pt-Based One-Dimensional Hierarchically Porous Nanostructures with Large Mesopores as Highly Efficient ORR Catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Fu, Shaofang; Zhu, Chengzhou; Song, Junhua; Engelhard, Mark H.; Xia, Haibing; Du, Dan; Lin, Yuehe

    2016-12-28

    Rational design and construction of Pt-based porous nanostructures with large mesopores have triggered significant considerations because of their high surface area and more efficient mass transport. Hydrochloric acid-induced kinetic reduction of metal precursors in the presence of soft template F-127 and hard template tellurium nanowires has been successfully demonstrated to construct one-dimensional hierarchical porous PtCu alloy nanostructures with large mesopores. Moreover, the electrochemical experiments demonstrated that the resultant PtCu hierarchically porous nanostructures with optimized composition exhibit enhanced electrocatalytic performance for oxygen reduction reaction.

  1. A high performance flexible all solid state supercapacitor based on the MnO2 sphere coated macro/mesoporous Ni/C electrode and ionic conducting electrolyte

    Science.gov (United States)

    Zhi, Jian; Reiser, Oliver; Wang, Youfu; Hu, Aiguo

    2016-06-01

    A high contact resistance between the active materials and the current collector, a low ionic conductivity of the gel electrolyte, and an impenetrable electrode structure are the three major barriers which greatly limit the capacitance of MnO2 in solid state supercapacitors. As a potential solution to these problems, in this work we report a novel electrode for solid state supercapacitors, based on a ternary system composed of hierarchical MnO2 spheres as the active material, macroporous Ni foam as gel penetrable skeletons and an ordered mesoporous carbon (OMC) membrane as the charge-transport accelerating layer. By employing butyl-3-methylimidazolium chloride (BMIMCl) modified gels as the ionic conducting electrolyte, the utilization efficiency of MnO2 on the specific capacitance was enhanced up to 88% of the theoretical value, delivering a volumetric capacitance of 81 F cm-3, which is the highest value among MnO2 based solid state supercapacitors. Moreover, such a flexible device exhibits exceptional volumetric energy and power density (6.6 Wh L-1 and 549 W L-1, based on the whole device volume) combined with a small capacity loss of 8.5% after 6000 cycles under twisting. These encouraging findings unambiguously overcome the energy bottleneck of MnO2 in solid state supercapacitors, and open up a new application of macro/mesoporous materials in flexible devices.A high contact resistance between the active materials and the current collector, a low ionic conductivity of the gel electrolyte, and an impenetrable electrode structure are the three major barriers which greatly limit the capacitance of MnO2 in solid state supercapacitors. As a potential solution to these problems, in this work we report a novel electrode for solid state supercapacitors, based on a ternary system composed of hierarchical MnO2 spheres as the active material, macroporous Ni foam as gel penetrable skeletons and an ordered mesoporous carbon (OMC) membrane as the charge-transport accelerating

  2. Surface-Casting Synthesis of Mesoporous Zirconia with a CMK-5-Like Structure and High Surface Area.

    Science.gov (United States)

    Gu, Dong; Schmidt, Wolfgang; Pichler, Christian M; Bongard, Hans-Josef; Spliethoff, Bernd; Asahina, Shunsuke; Cao, Zhengwen; Terasaki, Osamu; Schüth, Ferdi

    2017-09-04

    About 15 years ago, the Ryoo group described the synthesis of CMK-5, a material consisting of a hexagonal arrangement of carbon nanotubes. Extension of the surface casting synthesis to oxide compositions, however, was not possible so far, in spite of many attempts. Here it is demonstrated, that crystalline mesoporous hollow zirconia materials with very high surface areas up to 400 m 2  g -1 , and in selected cases in the form of CMK-5-like, are indeed accessible via such a surface casting process. The key for the successful synthesis is an increased interaction between the silica hard template surface and the zirconia precursor species by using silanol group-rich mesoporous silica as a hard template. The surface areas of the obtained zirconias exceed those of conventionally hard-templated ones by a factor of two to three. The surface casting process seems to be applicable also to other oxide materials. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Mesoporous cobalt monoxide nanorods grown on reduced graphene oxide nanosheets with high lithium storage performance

    International Nuclear Information System (INIS)

    Zhu, Wenjun; Huang, Hui; Gan, Yongping; Tao, Xinyong; Xia, Yang; Zhang, Wenkui

    2014-01-01

    Graphical abstract: - Highlights: • Facile synthesis of mesoporous CoO NRs/rGO composite by a hydrothermal method. • The composite has an unique 1D porous nanorods/2D sheets hybrid nanostructure. • The CoO NRs/rGO composite shows excellent electrochemical performance as anode materials for Li-ion batteries. - Abstract: Graphene-based hybrid nanostructures could offer many opportunities for improved lithium storage performance. Herein, we report a facile synthesis of mesoporous CoO nanorods (CoO NRs) on a reduced graphene oxide (rGO) substrate by hydrothermal and calcination treatment. Transmission electron microscopy (TEM) investigation reveals that the CoO NRs with a diameter of 20–60 nm are tightly anchored on the surface of rGO sheets. Compared to pure CoO NRs, the CoO NRs/rGO composite shows higher lithium storage capacity and superior rate capability as anode materials for Li-ion batteries. The CoO NRs/rGO composite delivers an initial discharge capacity of 1452 mAh g −1 , and it can still remains 960 mAh g −1 after 50 cycles at 0.1 A g −1 . After each 10 cycles at 0.1, 0.2, 0.5, and 1 A g −1 , the specific capacities of the composite are about 1096, 1049, 934 and 513 mAh g −1 , respectively. The enhanced electrochemical performance of the composite is closely related to its unique structure, such as 1D mesoporous morphology of CoO NRs and its tightly-contacting with rGO nanosheets, which could shorten the transport pathway for both electrons and ions, enhance the electrical conductivity and accommodate the volume expansion during prolonged cycling

  4. A highly stable zeotype mesoporous zirconium metal-organic framework with ultralarge pores.

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Dawei; Wang, Kecheng; Su, Jie; Liu, Tian-Fu; Park, Jihye; Wei, Zhangwen; Bosch, Mathieu; Yakovenko, Andrey; Zou, Xiaodong; Zhou, Hong-Cai

    2015-01-02

    Through topological rationalization, a zeotype mesoporous Zr-containing metal-organic framework (MOF), namely PCN-777, has been designed and synthesized. PCN-777 exhibits the largest cage size of 3.8nm and the highest pore volume of 2.8cm(3)g(-1) among reported Zr-MOFs. Moreover, PCN-777 shows excellent stability in aqueous environments, which makes it an ideal candidate as a support to incorporate different functional moieties. Through facile internal surface modification, the interaction between PCN-777 and different guests can be varied to realize efficient immobilization

  5. Synthesis of CaO-SiO2-P2O5 mesoporous bioactive glasses with high P2O5 content by evaporation induced self assembly process.

    Science.gov (United States)

    Zhao, Shan; Li, Yanbao; Li, Dongxu

    2011-02-01

    Mesoporous bioactive glasses (MBGs) of the CaO-SiO(2)-P(2)O(5) system containing relatively high P(2)O(5) contents (10-30 mol%) were prepared from a sol-gel. An evaporation-induced self-assembly (EISA) technique was used with poly(ethylene oxide)-block-poly(propylene oxide)-block-poly(ethylene oxide) (EO(20)-PO(70)-EO(20), P123) acting as a template. The structural, morphological and textural properties of MBGs were investigated by small-angle X-ray diffraction (SAXRD), transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy and a N(2) sorption/desorption technique. SAXRD and TEM results display the reduced long-range ordering of mesopores with increasing P(2)O(5) content. N(2) sorption/desorption analysis shows that all three samples exhibit a type IV isotherm with type H1 hysteresis loops, characteristic of independent cylindrical slim pore channels and this material has a Barret-Joyner-Halenda (BJH) model pore size of ~4 nm and BET specific surface area ~430 m(2)/g. NMR results indicate a more condensed framework for samples with 30 mol% P(2)O(5) than samples with 10 mol% P(2)O(5). For in vitro bioactivity tests where samples were soaked in simulated body fluid (SBF), samples with 30 mol% P(2)O(5) showed higher crystallinity than those with lower P(2)O(5) contents Silicon concentration increased in SBF solution during the soaking period, which indicates MBGs can be degradable in SBF solution.

  6. High order Poisson Solver for unbounded flows

    DEFF Research Database (Denmark)

    Hejlesen, Mads Mølholm; Rasmussen, Johannes Tophøj; Chatelain, Philippe

    2015-01-01

    This paper presents a high order method for solving the unbounded Poisson equation on a regular mesh using a Green’s function solution. The high order convergence was achieved by formulating mollified integration kernels, that were derived from a filter regularisation of the solution field....... The method was implemented on a rectangular domain using fast Fourier transforms (FFT) to increase computational efficiency. The Poisson solver was extended to directly solve the derivatives of the solution. This is achieved either by including the differential operator in the integration kernel...... the equations of fluid mechanics as an example, but can be used in many physical problems to solve the Poisson equation on a rectangular unbounded domain. For the two-dimensional case we propose an infinitely smooth test function which allows for arbitrary high order convergence. Using Gaussian smoothing...

  7. Bio-assisted synthesis of mesoporous Li3V2(PO4)3 for high performance lithium-ion batteries

    International Nuclear Information System (INIS)

    He, Wen; Zhang, Xudong; Du, Xiaoyong; Zhang, Yang; Yue, Yuanzheng; Shen, Jianxing; Li, Mei

    2013-01-01

    Graphical abstract: - Highlights: • We present a biomimetic way for obtaining mesoporous biocarbon coated Li 3 V 2 (PO 4 ) 3 (MBC-LVP). • This method is to apply yeasts as a structural template and a biocarbon source. • The MBC-LVP has uniform particles and fine biocarbon coating network structure. • The MBC-LVP exhibits outstanding electrochemical performances. - Abstract: The mesoporous biocarbon coated Li 3 V 2 (PO 4 ) 3 (MBC-LVP) cathode material is synthesized by a biotemplate-assisted sol–gel reaction process using low-cost beer waste brewing yeasts (BWBYs) as both structural template and biocarbon source. The structure and electrochemical performances of MBC-LVP were investigated using Raman spectra, thermogravimetric measurements (TGA), adsorption–desorption isotherms and pore-size-distribution curves, X-ray diffraction (XRD), transmission electron microscope (TEM and HRTEM), and electrochemical methods. The results show that the MBC-LVP synthesized at 750 °C has a hierarchical nanostructure, which consist of Li 3 V 2 (PO 4 ) 3 crystal nanoparticles and amorphous biocarbons network (11.5%) with hierarchical mesoporous structures (slit shape mesopores, open wormlike mesopores and plugged mesopores). This hierarchical nanostructure facilitates electron and lithium ion diffusion. The MBC-LVP electrode has high discharge capacity (about 205 mAh g −1 ) at a current density of 0.2 C in the voltage region of 3.0–4.8 V and the diffusion coefficient of Li + -ions determined by CV and EIS is higher than those of olivine LiFePO 4 . We have revealed the formation mechanism of MBC-LVP, the possible lithium pathways in the MBC-LVP and established a relation between the structure and the ionic and electronic transport properties

  8. High Capacitive Storage Performance of Sulfur and Nitrogen Codoped Mesoporous Graphene.

    Science.gov (United States)

    Ma, Xinlong; Gao, Daowei

    2018-03-22

    Mesoporous graphene is synthesized based on the chemical vapor deposition methodology by using heavy MgO flakes as substrates in a fluidized-bed reactor. Subsequently, sulfur and nitrogen coincorporation into graphene frameworks is realized by the reaction between carbon atoms and thiourea molecules. The as-obtained sulfur and nitrogen codoped mesoporous graphene (SNMG) exhibits remarkable capacitive energy-storage behavior, as a result of well-developed pore channels, in terms of that in a symmetric supercapacitor and lithium-ion hybrid capacitor (LIHC). The ultrahigh durability of the SNMG/SNMG symmetric supercapacitor is demonstrated by long-term cycling, for which no capacitance decay is found after 20 000 cycles. A LIHC constructed from commercial Li 4 Ti 5 O 12 (LTO) as the anode and SNMG as the cathode is capable of delivering much enhanced lithium-storage ability and better rate capability than that of activated carbon (AC)/LTO LIHC. Moreover, SNMG/LTO LIHC exhibits maximum energy and power densities of 86.2 Wh kg -1 and 7443 W kg -1 and maintains 87 % capacitance retention after 2000 cycles. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Mesoporous Silicon Sponge as an Anti-Pulverization Structure for High-Performance Lithium-ion Battery Anodes

    Energy Technology Data Exchange (ETDEWEB)

    Li, Xiaolin; Gu, Meng; Hu, Shenyang Y.; Kennard, Rhiannon; Yan, Pengfei; Chen, Xilin; Wang, Chong M.; Sailor, Michael J.; Zhang, Jiguang; Liu, Jun

    2014-07-08

    Nanostructured silicon is a promising anode material for high performance lithium-ion batteries, yet scalable synthesis of such materials, and retaining good cycling stability in high loading electrode remain significant challenges. Here, we combine in-situ transmission electron microscopy and continuum media mechanical calculations to demonstrate that large (>20 micron) mesoporous silicon sponge (MSS) prepared by the scalable anodization method can eliminate the pulverization of the conventional bulk silicon and limit particle volume expansion at full lithiation to ~30% instead of ~300% as observed in bulk silicon particles. The MSS can deliver a capacity of ~750 mAh/g based on the total electrode weight with >80% capacity retention over 1000 cycles. The first-cycle irreversible capacity loss of pre-lithiated MSS based anode is only <5%. The insight obtained from MSS also provides guidance for the design of other materials that may experience large volume variation during operations.

  10. Mesoporous coaxial titanium nitride-vanadium nitride fibers of core-shell structures for high-performance supercapacitors.

    Science.gov (United States)

    Zhou, Xinhong; Shang, Chaoqun; Gu, Lin; Dong, Shanmu; Chen, Xiao; Han, Pengxian; Li, Lanfeng; Yao, Jianhua; Liu, Zhihong; Xu, Hongxia; Zhu, Yuwei; Cui, Guanglei

    2011-08-01

    In this study, titanium nitride-vanadium nitride fibers of core-shell structures were prepared by the coaxial electrospinning, and subsequently annealed in the ammonia for supercapacitor applications. These core-shell (TiN-VN) fibers incorporated mesoporous structure into high electronic conducting transition nitride hybrids, which combined higher specific capacitance of VN and better rate capability of TiN. These hybrids exhibited higher specific capacitance (2 mV s(-1), 247.5 F g(-1)) and better rate capability (50 mV s(-1), 160.8 F g(-1)), which promise a good candidate for high-performance supercapacitors. It was also revealed by electrochemical impedance spectroscopy (EIS) and X-ray photoelectron spectroscopy (XPS) characterization that the minor capacitance fade originated from the surface oxidation of VN and TiN.

  11. Ultrathin mesoporous Co_3O_4 nanosheets-constructed hierarchical clusters as high rate capability and long life anode materials for lithium-ion batteries

    International Nuclear Information System (INIS)

    Wu, Shengming; Xia, Tian; Wang, Jingping; Lu, Feifei; Xu, Chunbo; Zhang, Xianfa; Huo, Lihua; Zhao, Hui

    2017-01-01

    Graphical abstract: Ultrathin mesoporous Co_3O_4 nanosheets-constructed hierarchical clusters (UMCN-HCs) have been successfully synthesized via a facile hydrothermal method followed by a subsequent thermolysis treatment. When tested as anode materials for LIBs, UMCN-HCs achieve high reversible capacity, good long cycling life, and rate capability. - Highlights: • UMCN-HCs show high capacity, excellent stability, and good rate capability. • UMCN-HCs retain a capacity of 1067 mAh g"−"1 after 100 cycles at 100 mA g"−"1. • UMCN-HCs deliver a capacity of 507 mAh g"−"1 after 500 cycles at 2 A g"−"1. - Abstract: Herein, Ultrathin mesoporous Co_3O_4 nanosheets-constructed hierarchical clusters (UMCN-HCs) have been successfully synthesized via a facile hydrothermal method followed by a subsequent thermolysis treatment at 600 °C in air. The products consist of cluster-like Co_3O_4 microarchitectures, which are assembled by numerous ultrathin mesoporous Co_3O_4 nanosheets. When tested as anode materials for lithium-ion batteries, UMCN-HCs deliver a high reversible capacity of 1067 mAh g"−"1 at a current density of 100 mA g"−"1 after 100 cycles. Even at 2 A g"−"1, a stable capacity as high as 507 mAh g"−"1 can be achieved after 500 cycles. The high reversible capacity, excellent cycling stability, and good rate capability of UMCN-HCs may be attributed to their mesoporous sheet-like nanostructure. The sheet-layered structure of UMCN-HCs may buffer the volume change during the lithiation-delithiation process, and the mesoporous characteristic make lithium-ion transfer more easily at the interface between the active electrode and the electrolyte.

  12. High-order nonlinear susceptibilities of He

    International Nuclear Information System (INIS)

    Liu, W.C.; Clark, C.W.

    1996-01-01

    High-order nonlinear optical response of noble gases to intense laser radiation is of considerable experimental interest, but is difficult to measure or calculate accurately. The authors have begun a set of calculations of frequency-dependent nonlinear susceptibilities of He 1s, within the framework of Rayleigh=Schroedinger perturbation theory at lowest applicable order, with the goal of providing critically evaluated atomic data for modelling high harmonic generation processes. The atomic Hamiltonian is decomposed in term of Hylleraas coordinates and spherical harmonics using the formalism of Ponte and Shakeshaft, and the hierarchy of inhomogeneous equations of perturbation theory is solved iteratively. A combination of Hylleraas and Frankowski basis functions is used; the compact Hylleraas basis provides a highly accurate representation of the ground state wavefunction, whereas the diffuse Frankowski basis functions efficiently reproduce the correct asymptotic structure of the perturbed orbitals

  13. Heteroatom Polymer-Derived 3D High-Surface-Area and Mesoporous Graphene Sheet-Like Carbon for Supercapacitors.

    Science.gov (United States)

    Sheng, Haiyang; Wei, Min; D'Aloia, Alyssa; Wu, Gang

    2016-11-09

    Current supercapacitors suffer from low energy density mainly due to the high degree of microporosity and insufficient hydrophilicity of their carbon electrodes. Development of a supercapacitor capable of simultaneously storing as much energy as a battery, along with providing sufficient power and long cycle stability would be valued for energy storage applications and innovations. Differing from commonly studied reduced graphene oxides, in this work we identified an inexpensive heteroatom polymer (polyaniline-PANI) as a carbon/nitrogen precursor, and applied a controlled thermal treatment at elevated temperature to convert PANI into 3D high-surface-area graphene-sheet-like carbon materials. During the carbonization process, various transition metals including Fe, Co, and Ni were added, which play critical roles in both catalyzing the graphitization and serving as pore forming agents. Factors including post-treatments, heating temperatures, and types of metal were found crucial for achieving enhanced capacitance performance on resulting carbon materials. Using FeCl 3 as precursor along with optimal heating temperature 1000 °C and mixed acid treatment (HCl+HNO 3 ), the highest Brunauer-Emmett-Teller (BET) surface area of 1645 m 2 g -1 was achieved on the mesopore dominant graphene-sheet-like carbon materials. The unique morphologies featured with high-surface areas, dominant mesopores, proper nitrogen doping, and 3D graphene-like structures correspond to remarkably enhanced electrochemical specific capacitance up to 478 Fg -1 in 1.0 M KOH at a scan rate of 5 mV s -1 . Furthermore, in a real two-electrode system of a symmetric supercapacitor, a specific capacitance of 235 Fg -1 using Nafion binder is obtained under a current density of 1 Ag -1 by galvanostatic charge-discharge tests in 6.0 M KOH. Long-term cycle stability up to 5000 cycles by using PVDF binder in electrode was systematically evaluated as a function of types of metals and current densities.

  14. Highly Dispersed Nickel-Containing Mesoporous Silica with Superior Stability in Carbon Dioxide Reforming of Methane: The Effect of Anchoring

    Directory of Open Access Journals (Sweden)

    Wenjia Cai

    2014-03-01

    Full Text Available A series of nickel-containing mesoporous silica samples (Ni-SiO2 with different nickel content (3.1%–13.2% were synthesized by the evaporation-induced self-assembly method. Their catalytic activity was tested in carbon dioxide reforming of methane. The characterization results revealed that the catalysts, e.g., 6.7%Ni-SiO2, with highly dispersed small nickel particles, exhibited excellent catalytic activity and long-term stability. The metallic nickel particle size was significantly affected by the metal anchoring effect between metallic nickel particles and unreduced nickel ions in the silica matrix. A strong anchoring effect was suggested to account for the remaining of small Ni particle size and the improved catalytic performance.

  15. Highly improved ethanol gas-sensing performance of mesoporous nickel oxides nanowires with the stannum donor doping

    Science.gov (United States)

    Wei, Junqi; Li, Xiaoqing; Han, Yanbing; Xu, Jingcai; Jin, Hongxiao; Jin, Dingfeng; Peng, Xiaoling; Hong, Bo; Li, Jing; Yang, Yanting; Ge, Hongliang; Wang, Xinqing

    2018-06-01

    Mesoporous nickel oxides (NiO) and stannum(Sn)-doped NiO nanowires (NWs) were synthesized by using SBA-15 templates with the nanocasting method. X-ray diffraction, transmission electron microscope, energy dispersive spectrometry, nitrogen adsorption/desorption isotherm and UV–vis spectrum were used to characterize the phase structure, components and microstructure of the as-prepared samples. The gas-sensing analysis indicated that the Sn-doping could greatly improve the ethanol sensitivity for mesoporous NiO NWs. With the increasing Sn content, the ethanol sensitivity increased from 2.16 for NiO NWs up to the maximum of 15.60 for Ni0.962Sn0.038O1.038, and then decreased to 12.24 for Ni0.946Sn0.054O1.054 to 100 ppm ethanol gas at 340 °C. The high surface area from the Sn-doping improved the adsorption of oxygen on the surface of NiO NWs, resulting in the smaller surface resistance in air. Furthermore, owing to the recombination of the holes in hole-accumulation lay with the electrons from the donor impurity level and the increasing the body defects for Sn-doping, the total resistance in ethanol gas enhanced greatly. It was concluded that the sensitivity of Sn-doped NiO NWs based sensor could be greatly improved by the higher surface area and high-valence donor substitution from Sn-doping.

  16. Macrocyclic ligand decorated ordered mesoporous silica with large-pore and short-channel characteristics for effective separation of lithium isotopes: synthesis, adsorptive behavior study and DFT modeling.

    Science.gov (United States)

    Liu, Yuekun; Liu, Fei; Ye, Gang; Pu, Ning; Wu, Fengcheng; Wang, Zhe; Huo, Xiaomei; Xu, Jian; Chen, Jing

    2016-10-18

    Effective separation of lithium isotopes is of strategic value which attracts growing attention worldwide. This study reports a new class of macrocyclic ligand decorated ordered mesoporous silica (OMS) with large-pore and short-channel characteristics, which holds the potential to effectively separate lithium isotopes in aqueous solutions. Initially, a series of benzo-15-crown-5 (B15C5) derivatives containing different electron-donating or -withdrawing substituents were synthesized. Extractive separation of lithium isotopes in a liquid-liquid system was comparatively studied, highlighting the effect of the substituent, solvent, counter anion and temperature. The optimal NH 2 -B15C5 ligands were then covalently anchored to a short-channel SBA-15 OMS precursor bearing alkyl halides via a post-modification protocol. Adsorptive separation of the lithium isotopes was fully investigated, combined with kinetics and thermodynamics analysis, and simulation by using classic adsorption isotherm models. The NH 2 -B15C5 ligand functionalized OMSs exhibited selectivity to lithium ions against other alkali metal ions including K(i). Additionally, a more efficient separation of lithium isotopes could be obtained at a lower temperature in systems with softer counter anions and solvents with a lower dielectric constant. The highest value separation factor (α = 1.049 ± 0.002) was obtained in CF 3 COOLi aqueous solution at 288.15 K. Moreover, theoretical computation based on the density functional theory (DFT) was performed to elucidate the complexation interactions between the macrocyclic ligands and lithium ions. A suggested mechanism involving an isotopic exchange equilibrium was proposed to describe the lithium isotope separation by the functionalized OMSs.

  17. Substituent effect on the oxidation peak potentials of phenol derivatives at ordered mesoporous carbons modified electrode and its application in determination of acidity coefficients (pKa)

    International Nuclear Information System (INIS)

    Zhang, Tingting; Lang, Qiaolin; Zeng, Lingxing; Li, Tie; Wei, Mingdeng; Liu, Aihua

    2014-01-01

    In this paper, the relationship between the electrochemical characteristics and the structure of a series of substituted phenol derivatives with electron-donating or electron-withdrawing groups were studied by voltammetry using ordered mesoporous carbons (OMCs) modified glassy carbon electrode (GCE) (OMCs/GCE). p-Nitrophenol (p-NP) and p-methylphenol were selected as models of electron-withdrawing and electron-donating groups, respectively, to illustrate the electrochemical behavior and reaction mechanism of substituted phenols. Voltammetric study showed that the oxidation peak potential (E pa ) of substituted phenols with an electron-withdrawing group was systematically higher than that of substituted phenols with an electron-donating group. That is, the direct electrochemical oxidation of substituted phenol with an electron-withdrawing group is more difficult than that of substituted phenol with an electron-donating group. The E pa value shifted negatively with the increase of pKa for both p-substituted phenols and o-substituted phenols with the equations of pKa = −6.986 E pa + 13.261 (for p-substituted phenols) and pKa = −7.929 E pa + 13.831 (for o-substituted phenols). Thus, a simple and novel method was proposed for the precise prediction of the pKa of substituted phenols by determining E pa values with voltammetry at OMCs/GCE, which matched fairly with the results calculated from Hammett's constants. Thus, the present work may provide additional strategy to determine pKa values and investigate possible mechanisms of some organic reactions. In addition, by making use of the substituent effect, different p-substituted phenols (or o-substituted phenols) can be well separated and identified at OMCs/GCE by voltametry, which may find possible applications in simultaneous detection of p-substituted phenols (or o-substituted phenols)

  18. High-order nonuniformly correlated beams

    Science.gov (United States)

    Wu, Dan; Wang, Fei; Cai, Yangjian

    2018-02-01

    We have introduced a class of partially coherent beams with spatially varying correlations named high-order nonuniformly correlated (HNUC) beams, as an extension of conventional nonuniformly correlated (NUC) beams. Such beams bring a new parameter (mode order) which is used to tailor the spatial coherence properties. The behavior of the spectral density of the HNUC beams on propagation has been investigated through numerical examples with the help of discrete model decomposition and fast Fourier transform (FFT) algorithm. Our results reveal that by selecting the mode order appropriately, the more sharpened intensity maxima can be achieved at a certain propagation distance compared to that of the NUC beams, and the lateral shift of the intensity maxima on propagation is closed related to the mode order. Furthermore, analytical expressions for the r.m.s width and the propagation factor of the HNUC beams on free-space propagation are derived by means of Wigner distribution function. The influence of initial beam parameters on the evolution of the r.m.s width and the propagation factor, and the relation between the r.m.s width and the occurring of the sharpened intensity maxima on propagation have been studied and discussed in detail.

  19. High order corrections to the renormalon

    International Nuclear Information System (INIS)

    Faleev, S.V.

    1997-01-01

    High order corrections to the renormalon are considered. Each new type of insertion into the renormalon chain of graphs generates a correction to the asymptotics of perturbation theory of the order of ∝1. However, this series of corrections to the asymptotics is not the asymptotic one (i.e. the mth correction does not grow like m.). The summation of these corrections for the UV renormalon may change the asymptotics by a factor N δ . For the traditional IR renormalon the mth correction diverges like (-2) m . However, this divergence has no infrared origin and may be removed by a proper redefinition of the IR renormalon. On the other hand, for IR renormalons in hadronic event shapes one should naturally expect these multiloop contributions to decrease like (-2) -m . Some problems expected upon reaching the best accuracy of perturbative QCD are also discussed. (orig.)

  20. Synthesis of S/Cr doped mesoporous TiO2 with high-active visible light degradation property via solid state reaction route

    International Nuclear Information System (INIS)

    Liu Shaoyou; Tang Qunli; Feng Qingge

    2011-01-01

    S/Cr doped mesoporous TiO 2 (S-TiO 2 , Cr-TiO 2 , S-Cr-TiO 2 ) were successfully synthesized via a simple, effective and environmental benign solid state reaction route. The low angle XRD patterns demonstrated that the resulting samples possess mesostructures. The further characterizations via N 2 adsorption-desorption and XPS showed that the typical S/Cr co-doped mesoporous TiO 2 (S-Cr-TiO 2 (5S-5Cr)) possesses mesopore with the high specific surface area of 118.4 m 2 /g and narrow pore size distribution, and both S and Cr have been incorporated into the lattice of TiO 2 with the amounts of 4.16% sulfur and 7.88% chromium, respectively. And Raman spectroscopy shows that the surface of S-Cr-TiO 2 (5S-5Cr) material possesses stretching vibrational peaks at ∼709, ∼793 cm -1 are assignable to the Ti-O-Cr, O-Cr (Ti)-OH bonds, respectively. Interestingly, the UV-vis displayed that the absorption regions of S/Cr doped mesoporous TiO 2 cover the visible light region. As for the series of S-Cr-TiO 2 samples, the absorption region even extends to near infrared region with strong adsorption. Moreover, compared with the pure titanium dioxide (P25-TiO 2 ), the photodegradation properties of bromocresol green (BCG) on the S/Cr doped mesoporous TiO 2 showed excellent photocatalytic properties under visible light irradiation. Within 50 min visible light irradiation, 82.6% of the initial BCG was degraded for the S-Cr-TiO 2 (6S-4Cr) photocatalyst.

  1. High drug load, stable, manufacturable and bioavailable fenofibrate formulations in mesoporous silica: a comparison of spray drying versus solvent impregnation methods.

    Science.gov (United States)

    Hong, Shiqi; Shen, Shoucang; Tan, David Cheng Thiam; Ng, Wai Kiong; Liu, Xueming; Chia, Leonard S O; Irwan, Anastasia W; Tan, Reginald; Nowak, Steven A; Marsh, Kennan; Gokhale, Rajeev

    2016-01-01

    Encapsulation of drugs in mesoporous silica using co-spray drying process has been recently explored as potential industrial method. However, the impact of spray drying on manufacturability, physiochemical stability and bioavailability in relation to conventional drug load processes are yet to be fully investigated. Using a 2(3) factorial design, this study aims to investigate the effect of drug-loading process (co-spray drying and solvent impregnation), mesoporous silica pore size (SBA-15, 6.5 nm and MCM-41, 2.5 nm) and percentage drug load (30% w/w and 50% w/w) on material properties, crystallinity, physicochemical stability, release profiles and bioavailability of fenofibrate (FEN) loaded into mesoporous silica. From the scanning electronic microscopy (SEM) images, powder X-ray diffraction and Differential scanning calorimetry measurements, it is indicated that the co-spray drying process was able to load up to 50% (w/w) FEN in amorphous form onto the mesoporous silica as compared to the 30% (w/w) for solvent impregnation. The in vitro dissolution rate of the co-spray dried formulations was also significantly (p = 0.044) better than solvent impregnated formulations at the same drug loading. Six-month accelerated stability test at 40 °C/75 RH in open dish indicated excellent physical and chemical stability of formulations prepared by both methods. The amorphous state of FEN and the enhanced dissolution profiles were well preserved, and very low levels of degradation were detected after storage. The dog data for the three selected co-spray-dried formulations revealed multiple fold increment in FEN bioavailability compared to the reference crystalline FEN. These results validate the viability of co-spray-dried mesoporous silica formulations with high amorphous drug load as potential drug delivery systems for poorly water soluble drugs.

  2. High order harmonic generation from plasma mirror

    International Nuclear Information System (INIS)

    Thaury, C.

    2008-09-01

    When an intense laser beam is focused on a solid target, its surface is rapidly ionized and forms a dense plasma that reflects the incident field. For laser intensities above few 10 15 W/cm 2 , high order harmonics of the laser frequency, associated in the time domain to a train of atto-second pulses (1 as = 10 18 s), can be generated upon this reflection. Because such a plasma mirror can be used with arbitrarily high laser intensities, this process should eventually lead to the production of very intense pulses in the X-ray domain. In this thesis, we demonstrate that for laser intensities about 10 19 W/cm 2 , two mechanisms can contribute to the generation of high order harmonics: the coherent wake emission and the relativistic emission. These two mechanisms are studied both theoretically and experimentally. In particular, we show that, thanks to very different properties, the harmonics generated by these two processes can be unambiguously distinguished experimentally. We then investigate the phase properties of the harmonic, in the spectral and in the spatial domain. Finally, we illustrate how to exploit the coherence of the generation mechanisms to get information on the dynamics of the plasma electrons. (author)

  3. Mesoporous TiO{sub 2} aggregate photoanode with high specific surface area and strong light scattering for dye-sensitized solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Li, Chunhui; Luo, Yanhong; Guo, Xiaozhi; Li, Dongmei [Key Laboratory for Renewable Energy, Chinese Academy of Sciences, Beijing Key Laboratory for New Energy Materials and Devices, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Mi, Jianli; So, Lasse; Hald, Peter [Center for Materials Crystallography, Department of Chemistry and Interdisciplinary Nanoscience Center, Aarhus University, DK-8000 Aarhus (Denmark); Meng, Qingbo, E-mail: qbmeng@iphy.ac.cn [Key Laboratory for Renewable Energy, Chinese Academy of Sciences, Beijing Key Laboratory for New Energy Materials and Devices, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Iversen, Bo B., E-mail: bo@chem.au.dk [Center for Materials Crystallography, Department of Chemistry and Interdisciplinary Nanoscience Center, Aarhus University, DK-8000 Aarhus (Denmark)

    2012-12-15

    Phase-pure anatase TiO{sub 2} nanocrystallite aggregates synthesized by a continuous supercritical fluid process have been first used for fabricating mesoporous photoanodes of dye-sensitized solar cells (DSCs). Due to the small size (11 nm) of the TiO{sub 2} nanocrystallites in the aggregates, the mesoporous photoanode provides a high specific surface area, 80 m{sup 2}/g, which ensures high dye loading. At the same time, the submicrometer-sized aggregates endow the mesoporous photoanode with strong light scattering effect. Therefore, the light harvesting efficiency of the photoanode is increased. With an improved short-circuit current density, a high overall power conversion efficiency of 8.65% (100 mW/cm{sup 2}, AM 1.5) is achieved without additional scattering layers, 12% enhanced compared with the DSCs fabricated from commercial Degussa P25 with exactly the same procedures. In addition, this supercritical fluid process is scalable and rapid (less than one minute) for TiO{sub 2} aggregates synthesis, which will push the commercialization of DSCs in the future. - Graphical abstract: Due to the special morphology and structure, the photoanode of DSCs provides high specific surface area and strong light scattering at the same time, which results in high conversion efficiencies of the DSCs. Table of contents: Thanks to the synchronous realization of high specific surface area and strong light scattering, a high efficiency of 8.65% was achieved based on a novel mesoporous TiO{sub 2} aggregates photoanode for DSCs. Highlights: Black-Right-Pointing-Pointer The TiO{sub 2} aggregate photoanode provides a possible route for highly efficient DSCs. Black-Right-Pointing-Pointer Photoanode with high dye loading and light scattering is successfully fabricated. Black-Right-Pointing-Pointer TiO{sub 2} synthesized by a supercritical fluid process is first applied to DSCs. Black-Right-Pointing-Pointer The synthesis method and high efficiency will push the commercialization of DSCs.

  4. Mesoporous tungsten titanate as matrix for matrix-assisted laser desorption/ionization time-of-flight mass spectrometry analysis of biomolecules

    International Nuclear Information System (INIS)

    Shan Zhe; Han Lu; Yuan Minjia; Deng Chunhui; Zhao Dongyuan; Tu Bo; Yang Pengyuan

    2007-01-01

    In this paper, mesoporous tungsten titanate (WTiO) with different nano-pore structures was utilized as matrix for the analysis of short peptides by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS). Effect of characteristic features of mesoporous matrices on laser desorption/ionization process was investigated. Experiments showed that the ordered two-dimensional and three-dimensional mesoporous matrices were superior in performance to the non-ordered WTiO matrix. The dramatic enhancement of signal sensitivity by the ordered mesoporous matrices can be reasonably attributed to the ordered structure, which facilitated the understanding on structure-function relationship in mesoporous cavity for laser desorption process of adsorbed biomolecules. With the ordered mesoporous matrix, the short peptides are successfully detected. The presence of trace alkali metal salt effectively increased the analyte ion yields and the MALDI-TOFMS using the inorganic mesoporous matrices displayed a high salt tolerance. The developed technique also showed a satisfactory performance in peptide-mapping and amino-acid sequencing analysis

  5. High Order Semi-Lagrangian Advection Scheme

    Science.gov (United States)

    Malaga, Carlos; Mandujano, Francisco; Becerra, Julian

    2014-11-01

    In most fluid phenomena, advection plays an important roll. A numerical scheme capable of making quantitative predictions and simulations must compute correctly the advection terms appearing in the equations governing fluid flow. Here we present a high order forward semi-Lagrangian numerical scheme specifically tailored to compute material derivatives. The scheme relies on the geometrical interpretation of material derivatives to compute the time evolution of fields on grids that deform with the material fluid domain, an interpolating procedure of arbitrary order that preserves the moments of the interpolated distributions, and a nonlinear mapping strategy to perform interpolations between undeformed and deformed grids. Additionally, a discontinuity criterion was implemented to deal with discontinuous fields and shocks. Tests of pure advection, shock formation and nonlinear phenomena are presented to show performance and convergence of the scheme. The high computational cost is considerably reduced when implemented on massively parallel architectures found in graphic cards. The authors acknowledge funding from Fondo Sectorial CONACYT-SENER Grant Number 42536 (DGAJ-SPI-34-170412-217).

  6. Mesoporous carbon materials

    Science.gov (United States)

    Dai, Sheng; Fulvio, Pasquale Fernando; Mayes, Richard T.; Wang, Xiqing; Sun, Xiao-Guang; Guo, Bingkun

    2014-09-09

    A conductive mesoporous carbon composite comprising conductive carbon nanoparticles contained within a mesoporous carbon matrix, wherein the conductive mesoporous carbon composite possesses at least a portion of mesopores having a pore size of at least 10 nm and up to 50 nm, and wherein the mesopores are either within the mesoporous carbon matrix, or are spacings delineated by surfaces of said conductive carbon nanoparticles when said conductive carbon nanoparticles are fused with each other, or both. Methods for producing the above-described composite, devices incorporating them (e.g., lithium batteries), and methods of using them, are also described.

  7. Formation of monodisperse mesoporous silica microparticles via spray-drying.

    Science.gov (United States)

    Waldron, Kathryn; Wu, Winston Duo; Wu, Zhangxiong; Liu, Wenjie; Selomulya, Cordelia; Zhao, Dongyuan; Chen, Xiao Dong

    2014-03-15

    In this work, a protocol to synthesize monodisperse mesoporous silica microparticles via a unique microfluidic jet spray-drying route is reported for the first time. The microparticles demonstrated highly ordered hexagonal mesostructures with surface areas ranging from ~900 up to 1500 m(2)/g and pore volumes from ~0.6 to 0.8 cm(3)/g. The particle size could be easily controlled from ~50 to 100 μm from the same diameter nozzle via changing the initial solute content, or changing the drying temperature. The ratio of the surfactant (CTAB) and silica (TEOS), and the amount of water in the precursor were found to affect the degree of ordering of mesopores by promoting either the self-assembly of the surfactant-silica micelles or the condensation of the silica as two competing processes in evaporation induced self-assembly. The drying rate and the curvature of particles also affected the self-assembly of the mesostructure. The particle mesostructure is not influenced by the inlet drying temperature in the range of 92-160 °C, with even a relatively low temperature of 92 °C producing highly ordered mesoporous microparticles. The spray-drying derived mesoporous silica microparticles, while of larger sizes and more rapidly synthesized, showed a comparable performance with the conventional mesoporous silica MCM-41 in controlled release of a dye, Rhodamine B, indicating that these spray dried microparticles could be used for the immobilisation and controlled release of small molecules. Copyright © 2013 Elsevier Inc. All rights reserved.

  8. Hierarchical activated mesoporous phenolic-resin-based carbons for supercapacitors.

    Science.gov (United States)

    Wang, Zhao; Zhou, Min; Chen, Hao; Jiang, Jingui; Guan, Shiyou

    2014-10-01

    A series of hierarchical activated mesoporous carbons (AMCs) were prepared by the activation of highly ordered, body-centered cubic mesoporous phenolic-resin-based carbon with KOH. The effect of the KOH/carbon-weight ratio on the textural properties and capacitive performance of the AMCs was investigated in detail. An AMC prepared with a KOH/carbon-weight ratio of 6:1 possessed the largest specific surface area (1118 m(2) g(-1)), with retention of the ordered mesoporous structure, and exhibited the highest specific capacitance of 260 F g(-1) at a current density of 0.1 A g(-1) in 1 M H2 SO4 aqueous electrolyte. This material also showed excellent rate capability (163 F g(-1) retained at 20 A g(-1)) and good long-term electrochemical stability. This superior capacitive performance could be attributed to a large specific surface area and an optimized micro-mesopore structure, which not only increased the effective specific surface area for charge storage but also provided a favorable pathway for efficient ion transport. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. General strategy for fabricating thoroughly mesoporous nanofibers

    KAUST Repository

    Hou, Huilin

    2014-12-03

    Recently, preparation of mesoporous fibers has attracted extensive attentions because of their unique and broad applications in photocatalysis, optoelectronics, and biomaterials. However, it remains a great challenge to fabricate thoroughly mesoporous nanofibers with high purity and uniformity. Here, we report a general, simple and cost-effective strategy, namely, foaming-assisted electrospinning, for producing mesoporous nanofibers with high purity and enhanced specific surface areas. As a proof of concept, the as-fabricated mesoporous TiO2 fibers exhibit much higher photocatalytic activity and stability than both the conventional solid counterparts and the commercially available P25. The abundant vapors released from the introduced foaming agents are responsible for the creation of pores with uniform spatial distribution in the spun precursor fibers. The present work represents a critically important step in advancing the electrospinning technique for generating mesoporous fibers in a facile and universal manner.

  10. High order harmonic generation from plasma mirrors

    International Nuclear Information System (INIS)

    George, H.

    2010-01-01

    When an intense laser beam is focused on a solid target, the target's surface is rapidly ionized and forms dense plasma that reflects the incident field. For laser intensities above few 10 to the power of 15 Wcm -2 , high order harmonics of the laser frequency, associated in the time domain to a train of atto-second pulses (1 as 10 -18 s), can be generated upon this reflection. In this thesis, we developed numerical tools to reveal original aspects of harmonic generation mechanisms in three different interaction regime: the coherent wake emission, the relativistic emission and the resonant absorption. In particular, we established the role of these mechanisms when the target is a very thin foil (thickness of the order of 100 nm). Then we study experimentally the spectral, spatial and coherence properties of the emitted light. We illustrate how to exploit these measurements to get information on the plasma mirror dynamics on the femtosecond and atto-second time scales. Last, we propose a technique for the single-shot complete characterization of the temporal structure of the harmonic light emission from the laser-plasma mirror interaction. (author)

  11. A mesoporous WO{sub 3−X}/graphene composite as a high-performance Li-ion battery anode

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Fei [C-Industry Incubation Center, Korea Research Institute of Chemical Technology (KRICT), Daejeon 305-600 (Korea, Republic of); Kim, Jong Gu [C-Industry Incubation Center, Korea Research Institute of Chemical Technology (KRICT), Daejeon 305-600 (Korea, Republic of); Department of Fine Chemical Engineering and Applied Chemistry, Chungnam National University, Daejeon 305-764 (Korea, Republic of); Lee, Chul Wee [C-Industry Incubation Center, Korea Research Institute of Chemical Technology (KRICT), Daejeon 305-600 (Korea, Republic of); University of Science and Technology (UST), Gajeong-ro, Yuseong-gu, Daejeon 305-333 (Korea, Republic of); Im, Ji Sun, E-mail: jsim@krict.re.kr [C-Industry Incubation Center, Korea Research Institute of Chemical Technology (KRICT), Daejeon 305-600 (Korea, Republic of); University of Science and Technology (UST), Gajeong-ro, Yuseong-gu, Daejeon 305-333 (Korea, Republic of)

    2014-10-15

    Graphical abstract: The highly flexible and conductive graphene layer can enhance electron transfer, protect metal oxides against disintegration and aggregation and buffer the strain induced by volume expansion during cycles. The mesoporous surface layer provides an open network for Li+ diffusion. - Highlights: • Novel cocktail effects of 2D mesoporous WO{sub 3−X}/graphene for lithium ion battery. • New approach for lithium ion battery by easy and unique synthesis method. • Mechanism study with proper data for understanding a reaction on anode surface. - Abstract: A novel mesoporous WO{sub 3−X}/graphene composite was developed. This material allowed rapid electron and Li{sup +} ion diffusion when used as a Li-ion battery (LIB) anode material. Remarkably, the graphene support protected WO{sub 3−X} from changing volume during the electrochemical cycling process; this process generally induces capacity loss. The current work describes a high-performance anode material for LIB that has highly dense WO{sub 3−X}, as well as high capacity, rate capability and stability.

  12. Facile Synthesis of A 3D Flower-Like Mesoporous Ni@C Composite Material for High-Energy Aqueous Asymmetric Supercapacitors.

    Science.gov (United States)

    Liu, Song; An, Cuihua; Zang, Lei; Chang, Xiaoya; Guo, Huinan; Jiao, Lifang; Wang, Yijing

    2018-04-16

    A 3D flower-like mesoporous Ni@C composite material has been synthesized by using a facile and economical one-pot hydrothermal method. This unique 3D flower-like Ni@C composite, which exhibited a high surface area (522.4 m 2  g -1 ), consisted of highly dispersed Ni nanoparticles on mesoporous carbon flakes. The effect of calcination temperature on the electrochemical performance of the Ni@C composite was systematically investigated. The optimized material (Ni@C 700) displayed high specific capacity (1306 F g -1 at 2 A g -1 ) and excellent cycling performance (96.7 % retention after 5000 cycles). Furthermore, an asymmetric supercapacitor (ASC) that contained Ni@C 700 as cathode and mesoporous carbon (MC) as anode demonstrated high energy density (60.4 W h kg -1 at a power density of 750 W kg -1 ). © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. 软模法磁性有序介孔炭的合成与表征%Synthesis and characterization of magnetic ordered mesoporous carbon materials using soft templating method

    Institute of Scientific and Technical Information of China (English)

    王加; 林汉森; 王秀芳

    2012-01-01

    Magnetic ordered mesoporous carbon is synthesized through soft templating method by using triblock-copolymer Pluronic F127 as soft template,resorcinol-formaldehyde (RF) as carbon precursor and ferric nitrate as an iron source. HC1 is used as the catalyst for RF polymerization. The resultant materials are characterized by X-ray diffraction, N2 sorption and vibrating-sample magnetometer measurements. The results show that magnetic ordered mesoporous carbons are obtained when the Fe/R ratio is 0. 025. For those with Fe/R ratios greater than this value,the ordering,the BET surface area,pore volume and pore size decrease. N2 sorption isotherms of all the samples show representative type IV curves with HI hysteresis loops, which indicates a typical mesoporous material. Magnetic hysteresis loops show that the remanent magnetization of Fe/OMC samples increases with the increase of the content of Fe. This research can provide scientific proof for the optimized synthesis and application in magnetic separation for magnetic ordered mesoporous carbons.%以三嵌段共聚物为软模,间苯二酚-甲醛为炭前躯体,硝酸铁为铁源合成了磁性有序介孔炭,用XRD、氮气吸附、磁性测试等方法对样品进行表征.结果表明,当硝酸铁与间苯二酚摩尔比为0.025、0.05及0.10时得到的介孔炭具有有序性,随着铁质量分数的增加,有序性降低,比表面积、孔容都相应减小.基本磁化曲线结果表明,随着铁质量分数的增加,饱和磁化强度随之增加(0.01~0.10 emu/g),材料具有较好的磁性,容易从溶液中分离,表现出良好的分离性能.为磁性有序介孔炭的优化合成及磁性分离应用提供科学依据.

  14. Engineering 3D bicontinuous hierarchically macro-mesoporous LiFePO4/C nanocomposite for lithium storage with high rate capability and long cycle stability.

    Science.gov (United States)

    Zhang, Qian; Huang, Shao-Zhuan; Jin, Jun; Liu, Jing; Li, Yu; Wang, Hong-En; Chen, Li-Hua; Wang, Bin-Jie; Su, Bao-Lian

    2016-05-16

    A highly crystalline three dimensional (3D) bicontinuous hierarchically macro-mesoporous LiFePO4/C nanocomposite constructed by nanoparticles in the range of 50~100 nm via a rapid microwave assisted solvothermal process followed by carbon coating have been synthesized as cathode material for high performance lithium-ion batteries. The abundant 3D macropores allow better penetration of electrolyte to promote Li(+) diffusion, the mesopores provide more electrochemical reaction sites and the carbon layers outside LiFePO4 nanoparticles increase the electrical conductivity, thus ultimately facilitating reverse reaction of Fe(3+) to Fe(2+) and alleviating electrode polarization. In addition, the particle size in nanoscale can provide short diffusion lengths for the Li(+) intercalation-deintercalation. As a result, the 3D macro-mesoporous nanosized LiFePO4/C electrode exhibits excellent rate capability (129.1 mA h/g at 2 C; 110.9 mA h/g at 10 C) and cycling stability (87.2% capacity retention at 2 C after 1000 cycles, 76.3% at 5 C after 500 cycles and 87.8% at 10 C after 500 cycles, respectively), which are much better than many reported LiFePO4/C structures. Our demonstration here offers the opportunity to develop nanoscaled hierarchically porous LiFePO4/C structures for high performance lithium-ion batteries through microwave assisted solvothermal method.

  15. Carbon-Free CoO Mesoporous Nanowire Array Cathode for High-Performance Aprotic Li-O2 Batteries.

    Science.gov (United States)

    Wu, Baoshan; Zhang, Hongzhang; Zhou, Wei; Wang, Meiri; Li, Xianfeng; Zhang, Huamin

    2015-10-21

    Although various kinds of catalysts have been developed for aprotic Li-O2 battery application, the carbon-based cathodes are still vulnerable to attacks from the discharge intermediates or products, as well as the accompanying electrolyte decomposition. To ameliorate this problem, the free-standing and carbon-free CoO nanowire array cathode was purposely designed for Li-O2 batteries. The single CoO nanowire formed as a special mesoporous structure, owing even comparable specific surface area and pore volume to the typical Super-P carbon particles. In addition to the highly selective oxygen reduction/evolution reactions catalytic activity of CoO cathodes, both excellent discharge specific capacity and cycling efficiency of Li-O2 batteries were obtained, with 4888 mAh gCoO(-1) and 50 cycles during 500 h period. Owing to the synergistic effect between elaborate porous structure and selective intermediate absorption on CoO crystal, a unique bimodal growth phenomenon of discharge products was occasionally observed, which further offers a novel mechanism to control the formation/decomposition morphology of discharge products in nanoscale. This research work is believed to shed light on the future development of high-performance aprotic Li-O2 batteries.

  16. Two-dimensional mesoporous carbon nanosheets and their derived graphene nanosheets: synthesis and efficient lithium ion storage.

    Science.gov (United States)

    Fang, Yin; Lv, Yingying; Che, Renchao; Wu, Haoyu; Zhang, Xuehua; Gu, Dong; Zheng, Gengfeng; Zhao, Dongyuan

    2013-01-30

    We report a new solution deposition method to synthesize an unprecedented type of two-dimensional ordered mesoporous carbon nanosheets via a controlled low-concentration monomicelle close-packing assembly approach. These obtained carbon nanosheets possess only one layer of ordered mesopores on the surface of a substrate, typically the inner walls of anodic aluminum oxide pore channels, and can be further converted into mesoporous graphene nanosheets by carbonization. The atomically flat graphene layers with mesopores provide high surface area for lithium ion adsorption and intercalation, while the ordered mesopores perpendicular to the graphene layer enable efficient ion transport as well as volume expansion flexibility, thus representing a unique orthogonal architecture for excellent lithium ion storage capacity and cycling performance. Lithium ion battery anodes made of the mesoporous graphene nanosheets have exhibited an excellent reversible capacity of 1040 mAh/g at 100 mA/g, and they can retain at 833 mAh/g even after numerous cycles at varied current densities. Even at a large current density of 5 A/g, the reversible capacity is retained around 255 mAh/g, larger than for most other porous carbon-based anodes previously reported, suggesting a remarkably promising candidate for energy storage.

  17. Machine Learning Control For Highly Reconfigurable High-Order Systems

    Science.gov (United States)

    2015-01-02

    calibration and applications,” Mechatronics and Embedded Systems and Applications (MESA), 2010 IEEE/ASME International Conference on, IEEE, 2010, pp. 38–43...AFRL-OSR-VA-TR-2015-0012 MACHINE LEARNING CONTROL FOR HIGHLY RECONFIGURABLE HIGH-ORDER SYSTEMS John Valasek TEXAS ENGINEERING EXPERIMENT STATION...DIMENSIONAL RECONFIGURABLE SYSTEMS FA9550-11-1-0302 Period of Performance 1 July 2011 – 29 September 2014 John Valasek Aerospace Engineering

  18. Functionalized mesoporous materials for adsorption and release of different drug molecules: A comparative study

    International Nuclear Information System (INIS)

    Wang Gang; Otuonye, Amy N.; Blair, Elizabeth A.; Denton, Kelley; Tao Zhimin; Asefa, Tewodros

    2009-01-01

    The adsorption capacity and release properties of mesoporous materials for drug molecules can be improved by functionalizing their surfaces with judiciously chosen organic groups. Functionalized ordered mesoporous materials containing various types of organic groups via a co-condensation synthetic method from 15% organosilane and by post-grafting organosilanes onto a pre-made mesoporous silica were synthesized. Comparative studies of their adsorption and release properties for various model drug molecules were then conducted. Functional groups including 3-aminopropyl, 3-mercaptopropyl, vinyl, and secondary amine groups were used to functionalize the mesoporous materials while rhodamine 6G and ibuprofen were utilized to investigate the materials' relative adsorption and release properties. The self-assembly of the mesoporous materials was carried out in the presence of cetyltrimethylammonium bromide (CTAB) surfactant, which produced MCM-41 type materials with pore diameters of ∼2.7-3.3 nm and moderate to high surface areas up to ∼1000 m 2 /g. The different functional groups introduced into the materials dictated their adsorption capacity and release properties. While mercaptopropyl and vinyl functionalized samples showed high adsorption capacity for rhodamine 6G, amine functionalized samples exhibited higher adsorption capacity for ibuprofen. While the diffusional release of ibuprofen was fitted on the Fickian diffusion model, the release of rhodamine 6G followed Super Case-II transport model. - Graphical abstract: The adsorption capacity and release properties of mesoporous materials for various drug molecules are tuned by functionalizing the surfaces of the materials with judiciously chosen organic groups. This work reports comparative studies of the adsorption and release properties of functionalized ordered mesoporous materials containing different hydrophobic and hydrophilic groups that are synthesized via a co-condensation and post-grafting methods for

  19. Microporous MOFs Engaged in the Formation of Nitrogen-Doped Mesoporous Carbon Nanosheets for High-Rate Supercapacitors.

    Science.gov (United States)

    Hou, Ya-Nan; Zhao, Zongbin; Yu, Zhengfa; Zhang, Su; Li, Shaofeng; Yang, Juan; Zhang, Han; Liu, Chang; Wang, Zhiyu; Qiu, Jieshan

    2018-02-21

    Nitrogen-doped mesoporous carbon nanosheets (NMCS) have been fabricated from zinc-based microporous metal-organic frameworks (ZIF-8) by pyrolysis in a molten salt medium. The as-prepared NMCS exhibit significantly improved specific capacitance (NMCS-8: 232 F g -1 at 0.5 A g -1 ) and capacitance retention ratio (75.9 % at 50 A g -1 ) compared with the micropore-dominant nitrogen-doped porous carbon polyhedrons (NPCP-5: 178 F g -1 at 0.5 A g -1 , 15.9 % at 20 A g -1 ) obtained by direct pyrolysis of nanocrystalline ZIF-8. The excellent capacitive performance and high rate performance of the NMCS can be attributed to their unique combination of structure and composition, that is, the two-dimensional and hierarchically porous structure provides a short ion-transport pathway and facilitates the supply of electrolyte ions, and the nitrogen-doped polar surface improves the interface wettability when used as an electrode. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Synthesis of nitrogen-doped mesoporous carbon from polyaniline with an F127 template for high-performance supercapacitors

    Science.gov (United States)

    Xin, Guoxiang; Wang, Yanhui; Jia, Shaopei; Tian, Pengfei; Zhou, Shuyu; Zang, Jianbing

    2017-11-01

    N-doped mesoporous carbons (N-MCs) were synthesized via the oxypolymerization of aniline with a Pluronic F127 template, sintering at 850 °C in N2 atmosphere, and activation in a KOH solution. The contrast experiments were carried out without the addition of F127 and the obtained sample was defined as N-Cs. The Brunaner-Emmett-Teller measurement, pore size distribution measurements, transmission electron microscopy, and X-ray photoelectron spectroscopy of N-MCs and N-Cs were performed. The specific areas of the N-MCs and N-Cs reached 721 and 394 m2 g-1, respectively. The specific capacitances of the N-MCs and N-Cs were as high as 318 and 106 F g-1 at 0.2 A g-1. The cycle life of N-MCs at different current densities was above 96% after 5000 cycles of charging and discharging, indicating that the N-MCs had excellent cycle stability.

  1. Periodic Mesoporous Organosilica Nanoparticles with Controlled Morphologies and High Drug/Dye Loadings for Multicargo Delivery in Cancer Cells

    KAUST Repository

    Croissant, Jonas G.

    2016-06-01

    Despite the worldwide interest generated by periodic mesoporous organosilica (PMO) bulk materials, the design of PMO nanomaterials with controlled morphology remains largely unexplored and their properties unknown. In this work, we describe the first study of PMO nanoparticles (NPs) based on meta-phenylene bridges, and we conducted a comparative structure–property relationship investigation with para-phenylene-bridged PMO NPs. Our findings indicate that the change of the isomer drastically affects the structure, morphology, size, porosity and thermal stability of PMO materials. We observed a much higher porosity and thermal stability of the para-based PMO which was likely due to a higher molecular periodicity. Additionally, the para isomer could generate multipodal NPs at very low stirring speed and upon this discovery we designed a phenylene–ethylene bridged PMO with a controlled Janus morphology. Unprecedentedly high payloads could be obtained from 40 to 110 wt % regardless of the organic bridge of PMOs. Finally, we demonstrate for the first time the co-delivery of two cargos by PMO NPs. Importantly, the cargo stability in PMOs did not require the capping of the pores, unlike pure silica, and the delivery could be autonomously triggered in cancer cells by acidic pH with nearly 70 % cell killing. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

  2. High order harmonic generation in rare gases

    Energy Technology Data Exchange (ETDEWEB)

    Budil, Kimberly Susan [Univ. of California, Davis, CA (United States)

    1994-05-01

    The process of high order harmonic generation in atomic gases has shown great promise as a method of generating extremely short wavelength radiation, extending far into the extreme ultraviolet (XUV). The process is conceptually simple. A very intense laser pulse (I ~1013-1014 W/cm2) is focused into a dense (~1017 particles/cm3) atomic medium, causing the atoms to become polarized. These atomic dipoles are then coherently driven by the laser field and begin to radiate at odd harmonics of the laser field. This dissertation is a study of both the physical mechanism of harmonic generation as well as its development as a source of coherent XUV radiation. Recently, a semiclassical theory has been proposed which provides a simple, intuitive description of harmonic generation. In this picture the process is treated in two steps. The atom ionizes via tunneling after which its classical motion in the laser field is studied. Electron trajectories which return to the vicinity of the nucleus may recombine and emit a harmonic photon, while those which do not return will ionize. An experiment was performed to test the validity of this model wherein the trajectory of the electron as it orbits the nucleus or ion core is perturbed by driving the process with elliptically, rather than linearly, polarized laser radiation. The semiclassical theory predicts a rapid turn-off of harmonic production as the ellipticity of the driving field is increased. This decrease in harmonic production is observed experimentally and a simple quantum mechanical theory is used to model the data. The second major focus of this work was on development of the harmonic "source". A series of experiments were performed examining the spatial profiles of the harmonics. The quality of the spatial profile is crucial if the harmonics are to be used as the source for experiments, particularly if they must be refocused.

  3. Mesoporous multi-shelled ZnO microspheres for the scattering layer of dye sensitized solar cell with a high efficiency

    Energy Technology Data Exchange (ETDEWEB)

    Xia, Weiwei; Mei, Chao; Zeng, Xianghua, E-mail: xhzeng@yzu.edu.cn; Wu, Guoqing; Shen, Xiaoshuang [College of Physics Science and Technology and Institute of Optoelectronic Technology, Yangzhou University, Yangzhou 225002 (China); Chang, Shuai [Beijing Key Laboratory of Nanophotonics and Ultrafine Optoelectronic Systems, School of Materials Science and Engineering, Beijing Institute of Technology, Beijing 100081 (China)

    2016-03-14

    Both light scattering and dye adsorbing are important for the power conversion efficiency PCE performance of dye sensitized solar cell (DSSC). Nanostructured scattering layers with a large specific surface area are regarded as an efficient way to improve the PCE by increasing dye adsorbing, but excess adsorbed dye will hinder light scattering and light penetration. Thus, how to balance the dye adsorbing and light penetration is a key problem to improve the PCE performance. Here, multiple-shelled ZnO microspheres with a mesoporous surface are fabricated by a hydrothermal method and are used as scattering layers on the TiO{sub 2} photoanode of the DSSC in the presence of N719 dye and iodine–based electrolyte, and the results reveal that the DSSCs based on triple shelled ZnO microsphere with a mesoporous surface exhibit an enhanced PCE of 7.66%, which is 13.0% higher than those without the scattering layers (6.78%), indicating that multiple-shelled microspheres with a mesoporous surface can ensure enough light scattering between the shells, and a favorable concentration of the adsorbed dye can improve the light penetration. These results may provide a promising pathway to obtain the high efficient DSSCs.

  4. Synergistic interaction and controllable active sites of nitrogen and sulfur co-doping into mesoporous carbon sphere for high performance oxygen reduction electrocatalysts

    Science.gov (United States)

    Oh, Taeseob; Kim, Myeongjin; Park, Dabin; Kim, Jooheon

    2018-05-01

    Nitrogen and sulfur co-doped mesoporous carbon sphere (NSMCS) was prepared as a metal-free catalyst by an economical and facile pyrolysis process. The mesoporous carbon spheres were derived from sodium carboxymethyl cellulose as the carbon source and the nitrogen and sulfur dopants were derived from urea and p-benzenedithiol, respectively. The doping level and chemical states of nitrogen and sulfur in the prepared NSMCS can be easily adjusted by controlling the pyrolysis temperature. The NSMCS pyrolyzed at 900 °C (NSMCS-900) exhibited higher oxygen reduction reaction activity than the mesoporous carbon sphere doped solely with nitrogen or sulfur, due to the synergistic effect of co-doping. Among all the NSMCS samples, NSMCS-900 exhibited excellent ORR catalytic activity owing to the presence of a highly active site, consisting of pyridinic N, graphitic N, and thiophene S. Remarkably, the NSMCS-900 catalyst was comparable with commercial Pt/C, in terms of the onset and the half-wave potentials and showed better durability than Pt/C for ORR in an alkaline electrolyte. The approach demonstrated in this work could be used to prepare promising metal-free electrocatalysts for application in energy conversion and storage.

  5. Phosphoryl functionalized mesoporous silica for uranium adsorption

    International Nuclear Information System (INIS)

    Xue, Guo; Yurun, Feng; Li, Ma; Dezhi, Gao; Jie, Jing; Jincheng, Yu; Haibin, Sun; Hongyu, Gong; Yujun, Zhang

    2017-01-01

    Highlights: • Phosphoryl functionalized mesoporous silica (TBP-SBA-15) is synthesized. • The amino and phosphoryl groups are successfully grafted on SBA-15. • TBP-SBA-15 has high and rapid uranium adsorption capacity in broad pH range. • The U(VI) adsorption of TBP-SBA-15 is spontaneous and belongs to chemical adsorption. - Abstract: Phosphoryl functionalized mesoporous silica (TBP-SBA-15) was synthesized by modified mesoporous silica with γ-amino propyl triethoxy silane and tributyl phosphate. The obtained samples were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), small angle X-ray diffraction (SAXRD), thermo-gravimetric/differential thermalanalyzer (TG/DTA), N_2 adsorption–desorption (BET) and Fourier transform infrared spectroscopy (FT-IR) techniques. Results showed that TBP-SBA-15 had large surface areas with ordered channel structure. Moreover, the effects of adsorption time, sorbent dose, solution pH, initial uranium concentration and temperature on the uranium adsorption behaviors were investigated. TBP-SBA-15 showed a high uranium adsorption capacity in a broad range of pH values. The U(VI) adsorption rate of TBP-SBA-15 was fast and nearly achieved completion in 10 min with the sorbent dose of 1 g/L. The U(VI) adsorption of TBP-SBA-15 followed the pseudo-second-order kinetic model and Freundlich isotherm model, indicating that the process was belonged to chemical adsorption. Furthermore, the thermodynamic parameters (ΔG"0, ΔH"0 and ΔS"0) confirmed that the adsorption process was endothermic and spontaneous.

  6. Phosphoryl functionalized mesoporous silica for uranium adsorption

    Energy Technology Data Exchange (ETDEWEB)

    Xue, Guo; Yurun, Feng; Li, Ma; Dezhi, Gao; Jie, Jing; Jincheng, Yu; Haibin, Sun [Key Laboratory for Liquid-Solid Structural Evolution & Processing of Materials of Ministry of Education, Shandong University, Jinan 250061 (China); Key Laboratory of Special Functional Aggregated Materials, Ministry of Education, Shandong University, Jinan 250061 (China); Hongyu, Gong, E-mail: gong_hongyu@163.com [Key Laboratory for Liquid-Solid Structural Evolution & Processing of Materials of Ministry of Education, Shandong University, Jinan 250061 (China); Key Laboratory of Special Functional Aggregated Materials, Ministry of Education, Shandong University, Jinan 250061 (China); Yujun, Zhang, E-mail: yujunzhangcn@163.com [Key Laboratory for Liquid-Solid Structural Evolution & Processing of Materials of Ministry of Education, Shandong University, Jinan 250061 (China); Key Laboratory of Special Functional Aggregated Materials, Ministry of Education, Shandong University, Jinan 250061 (China)

    2017-04-30

    Highlights: • Phosphoryl functionalized mesoporous silica (TBP-SBA-15) is synthesized. • The amino and phosphoryl groups are successfully grafted on SBA-15. • TBP-SBA-15 has high and rapid uranium adsorption capacity in broad pH range. • The U(VI) adsorption of TBP-SBA-15 is spontaneous and belongs to chemical adsorption. - Abstract: Phosphoryl functionalized mesoporous silica (TBP-SBA-15) was synthesized by modified mesoporous silica with γ-amino propyl triethoxy silane and tributyl phosphate. The obtained samples were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), small angle X-ray diffraction (SAXRD), thermo-gravimetric/differential thermalanalyzer (TG/DTA), N{sub 2} adsorption–desorption (BET) and Fourier transform infrared spectroscopy (FT-IR) techniques. Results showed that TBP-SBA-15 had large surface areas with ordered channel structure. Moreover, the effects of adsorption time, sorbent dose, solution pH, initial uranium concentration and temperature on the uranium adsorption behaviors were investigated. TBP-SBA-15 showed a high uranium adsorption capacity in a broad range of pH values. The U(VI) adsorption rate of TBP-SBA-15 was fast and nearly achieved completion in 10 min with the sorbent dose of 1 g/L. The U(VI) adsorption of TBP-SBA-15 followed the pseudo-second-order kinetic model and Freundlich isotherm model, indicating that the process was belonged to chemical adsorption. Furthermore, the thermodynamic parameters (ΔG{sup 0}, ΔH{sup 0} and ΔS{sup 0}) confirmed that the adsorption process was endothermic and spontaneous.

  7. A high performance totally ordered multicast protocol

    Science.gov (United States)

    Montgomery, Todd; Whetten, Brian; Kaplan, Simon

    1995-01-01

    This paper presents the Reliable Multicast Protocol (RMP). RMP provides a totally ordered, reliable, atomic multicast service on top of an unreliable multicast datagram service such as IP Multicasting. RMP is fully and symmetrically distributed so that no site bears un undue portion of the communication load. RMP provides a wide range of guarantees, from unreliable delivery to totally ordered delivery, to K-resilient, majority resilient, and totally resilient atomic delivery. These QoS guarantees are selectable on a per packet basis. RMP provides many communication options, including virtual synchrony, a publisher/subscriber model of message delivery, an implicit naming service, mutually exclusive handlers for messages, and mutually exclusive locks. It has commonly been held that a large performance penalty must be paid in order to implement total ordering -- RMP discounts this. On SparcStation 10's on a 1250 KB/sec Ethernet, RMP provides totally ordered packet delivery to one destination at 842 KB/sec throughput and with 3.1 ms packet latency. The performance stays roughly constant independent of the number of destinations. For two or more destinations on a LAN, RMP provides higher throughput than any protocol that does not use multicast or broadcast.

  8. Mesoporous carbon nitride based biosensor for highly sensitive and selective analysis of phenol and catechol in compost bioremediation.

    Science.gov (United States)

    Zhou, Yaoyu; Tang, Lin; Zeng, Guangming; Chen, Jun; Cai, Ye; Zhang, Yi; Yang, Guide; Liu, Yuanyuan; Zhang, Chen; Tang, Wangwang

    2014-11-15

    Herein, we reported here a promising biosensor by taking advantage of the unique ordered mesoporous carbon nitride material (MCN) to convert the recognition information into a detectable signal with enzyme firstly, which could realize the sensitive, especially, selective detection of catechol and phenol in compost bioremediation samples. The mechanism including the MCN based on electrochemical, biosensor assembly, enzyme immobilization, and enzyme kinetics (elucidating the lower detection limit, different linear range and sensitivity) was discussed in detail. Under optimal conditions, GCE/MCN/Tyr biosensor was evaluated by chronoamperometry measurements and the reduction current of phenol and catechol was proportional to their concentration in the range of 5.00 × 10(-8)-9.50 × 10(-6)M and 5.00 × 10(-8)-1.25 × 10(-5)M with a correlation coefficient of 0.9991 and 0.9881, respectively. The detection limits of catechol and phenol were 10.24 nM and 15.00 nM (S/N=3), respectively. Besides, the data obtained from interference experiments indicated that the biosensor had good specificity. All the results showed that this material is suitable for load enzyme and applied to the biosensor due to the proposed biosensor exhibited improved analytical performances in terms of the detection limit and specificity, provided a powerful tool for rapid, sensitive, especially, selective monitoring of catechol and phenol simultaneously. Moreover, the obtained results may open the way to other MCN-enzyme applications in the environmental field. Copyright © 2014 Elsevier B.V. All rights reserved.

  9. Novel strategy for the preparation of graphene-encapsulated mesoporous metal oxides with enhanced lithium storage

    International Nuclear Information System (INIS)

    Lin, Rong; Yue, Wenbo; Niu, Fangzhou; Ma, Jie

    2016-01-01

    As potential anode materials for lithium-ion batteries, mesoporous metal oxides show high reversible capacities but relatively poor cycle stability due to the structural collapse during cycles. Graphene-encapsulated mesoporous metal oxides may increase the electronic conductivity of the composite as well as stabilize the mesostructure of metal oxides, thereby enhancing the electrochemical performance of mesoporous metal oxides. Herein we describe a novel strategy for the preparation of graphene-encapsulated mesoporous metal oxides (SnO_2, Mn_3O_4), which exhibit superior electrochemical performance compared to pure mesoporous metal oxides. Moreover, some mesoporous metal oxides may be further reduced to low-valence metal oxides when calcined in presence of graphene. Mesoporous metal oxides with high isoelectric points are not essential for this synthesis method since metal oxides are connected with graphene through mesoporous silica template, thus expanding the types of graphene-encapsulated mesoporous metal oxides.

  10. Mesoporous mixed metal oxides derived from P123-templated Mg-Al layered double hydroxides

    International Nuclear Information System (INIS)

    Wang Jun; Zhou Jideng; Li Zhanshuang; He Yang; Lin Shuangshuang; Liu Qi; Zhang Milin; Jiang Zhaohua

    2010-01-01

    We report the preparation of mesoporous mixed metal oxides (MMOs) through a soft template method. Different amounts of P123 were used as structure directing agent to synthesize P123-templated Mg-Al layered double hydroxides (LDHs). After calcination of as-synthesized LDHs at 500 o C, the ordered mesopores were obtained by removal of P123. The mesoporous Mg-Al MMOs fabricated by using 2 wt% P123 exhibited a high specific surface area of 108.1 m 2 /g, and wide distribution of pore size (2-18 nm). An investigation of the 'memory effect' of the mesoporous MMOs revealed that they were successfully reconstructed to ibuprofen intercalated LDHs having different gallery heights, which indicated different intercalation capacities. Due to their mesoporosity these unique MMOs have particular potential as drug or catalyst carriers. - Graphical abstract: Ordered mesoporous Mg-Al MMOs can be obtained through the calcination of P123-templated Mg-Al-CO 3 LDHs. The pore diameter is 2.2 nm. At the presence of ibuprofen, the Mg-Al MMOs can recover to Mg-Al-IBU LDHs, based on its 'remember effect'. Display Omitted

  11. Multilayered High Surface Area "Brick and Mortar" Mesoporous Titania Films as Efficient Anodes in Dye-Sensitized Solar Cells

    Czech Academy of Sciences Publication Activity Database

    Szeifert, J. M.; Fattakhova-Rohlfing, D.; Rathouský, Jiří; Bein, T.

    2012-01-01

    Roč. 24, č. 4 (2012), s. 659-663 ISSN 0897-4756 Institutional research plan: CEZ:AV0Z40400503 Keywords : titanium dioxide * functional coatings * mesoporous metal oxides Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 8.238, year: 2012

  12. High order dark wavefront sensing simulations

    Science.gov (United States)

    Ragazzoni, Roberto; Arcidiacono, Carmelo; Farinato, Jacopo; Viotto, Valentina; Bergomi, Maria; Dima, Marco; Magrin, Demetrio; Marafatto, Luca; Greggio, Davide; Carolo, Elena; Vassallo, Daniele

    2016-07-01

    Dark wavefront sensing takes shape following quantum mechanics concepts in which one is able to "see" an object in one path of a two-arm interferometer using an as low as desired amount of light actually "hitting" the occulting object. A theoretical way to achieve such a goal, but in the realm of wavefront sensing, is represented by a combination of two unequal beams interferometer sharing the same incoming light, and whose difference in path length is continuously adjusted in order to show different signals for different signs of the incoming perturbation. Furthermore, in order to obtain this in white light, the path difference should be properly adjusted vs the wavelength used. While we incidentally describe how this could be achieved in a true optomechanical setup, we focus our attention to the simulation of a hypothetical "perfect" dark wavefront sensor of this kind in which white light compensation is accomplished in a perfect manner and the gain is selectable in a numerical fashion. Although this would represent a sort of idealized dark wavefront sensor that would probably be hard to match in the real glass and metal, it would also give a firm indication of the maximum achievable gain or, in other words, of the prize for achieving such device. Details of how the simulation code works and first numerical results are outlined along with the perspective for an in-depth analysis of the performances and its extension to more realistic situations, including various sources of additional noise.

  13. High order QED corrections in Z physics

    International Nuclear Information System (INIS)

    Marck, S.C. van der.

    1991-01-01

    In this thesis a number of calculations of higher order QED corrections are presented, all applying to the standard LEP/SLC processes e + e - → f-bar f, where f stands for any fermion. In cases where f≠ e - , ν e , the above process is only possible via annihilation of the incoming electron positron pair. At LEP/SLC this mainly occurs via the production and the subsequent decay of a Z boson, i.e. the cross section is heavily dominated by the Z resonance. These processes and the corrections to them, treated in a semi-analytical way, are discussed (ch. 2). In the case f = e - (Bhabha scattering) the process can also occur via the exchange of a virtual photon in the t-channel. Since the latter contribution is dominant at small scattering angles one has to exclude these angles if one is interested in Z physics. Having excluded that region one has to recalculate all QED corrections (ch. 3). The techniques introduced there enables for the calculation the difference between forward and backward scattering, the forward backward symmetry, for the cases f ≠ e - , ν e (ch. 4). At small scattering angles, where Bhabha scattering is dominated by photon exchange in the t-channel, this process is used in experiments to determine the luminosity of the e + e - accelerator. hence an accurate theoretical description of this process at small angles is of vital interest to the overall normalization of all measurements at LEP/SLC. Ch. 5 gives such a description in a semi-analytical way. The last two chapters discuss Monte Carlo techniques that are used for the cases f≠ e - , ν e . Ch. 6 describes the simulation of two photon bremsstrahlung, which is a second order QED correction effect. The results are compared with results of the semi-analytical treatment in ch. 2. Finally ch. 7 reviews several techniques that have been used to simulate higher order QED corrections for the cases f≠ e - , ν e . (author). 132 refs.; 10 figs.; 16 tabs

  14. Solution-Processed Ultrathin TiO2 Compact Layer Hybridized with Mesoporous TiO2 for High-Performance Perovskite Solar Cells.

    Science.gov (United States)

    Jeong, Inyoung; Park, Yun Hee; Bae, Seunghwan; Park, Minwoo; Jeong, Hansol; Lee, Phillip; Ko, Min Jae

    2017-10-25

    The electron transport layer (ETL) is a key component of perovskite solar cells (PSCs) and must provide efficient electron extraction and collection while minimizing the charge recombination at interfaces in order to ensure high performance. Conventional bilayered TiO 2 ETLs fabricated by depositing compact TiO 2 (c-TiO 2 ) and mesoporous TiO 2 (mp-TiO 2 ) in sequence exhibit resistive losses due to the contact resistance at the c-TiO 2 /mp-TiO 2 interface and the series resistance arising from the intrinsically low conductivity of TiO 2 . Herein, to minimize such resistive losses, we developed a novel ETL consisting of an ultrathin c-TiO 2 layer hybridized with mp-TiO 2 , which is fabricated by performing one-step spin-coating of a mp-TiO 2 solution containing a small amount of titanium diisopropoxide bis(acetylacetonate) (TAA). By using electron microscopies and elemental mapping analysis, we establish that the optimal concentration of TAA produces an ultrathin blocking layer with a thickness of ∼3 nm and ensures that the mp-TiO 2 layer has a suitable porosity for efficient perovskite infiltration. We compare PSCs based on mesoscopic ETLs with and without compact layers to determine the role of the hole-blocking layer in their performances. The hybrid ETLs exhibit enhanced electron extraction and reduced charge recombination, resulting in better photovoltaic performances and reduced hysteresis of PSCs compared to those with conventional bilayered ETLs.

  15. Rapid microwave-assisted synthesis of mesoporous NiMoO_4 nanorod/reduced graphene oxide composites for high-performance supercapacitors

    International Nuclear Information System (INIS)

    Liu, Ting; Chai, Hui; Jia, Dianzeng; Su, Ying; Wang, Tao; Zhou, Wanyong

    2015-01-01

    Graphical abstract: Mesoporous NiMoO_4-rGO shows high specific capacitance of 1274 F/g at 1 A/g and ultrahigh energy density of 30.3 Wh/kg at a power density of 187 W/kg. - Abstract: Mesoporous NiMoO_4 nanorods grown on the surface of reduced graphene oxide composites (NiMoO_4-rGO) were synthesized via a simple, rapidly, and environment-friendly microwave-solvothermal method. The structure and morphology of the composites were characterized by X-ray diffraction, Raman spectra, scanning electron microscopy, and transmission electron microscopy. The NiMoO_4-rGO composite exhibited high performance as an electrode material for supercapacitors. At a current density of 1 A g"−"1, the specific capacitance reached 1274 F g"−"1, which is higher than that of pure NiMoO_4 (800 F g"−"1). NiMoO_4-rGO can retain about 81.1% of its initial capacitance after 1000 charge/discharge cycles. Remarkably, NiMoO_4-rGO composites can be applied in asymmetric supercapacitors with ultrahigh energy density of 30.3 Wh kg"−"1 at a power density of 187 W kg"−"1. The enhanced electrochemical performance of NiMoO_4-rGO is mainly ascribed to the mesoporous-NiMoO_4 nanorods with large specific surface area, as well as high coupling with conductive rGO.

  16. Mesoporous Transition Metal Oxides for Supercapacitors

    OpenAIRE

    Wang, Yan; Guo, Jin; Wang, Tingfeng; Shao, Junfeng; Wang, Dong; Yang, Ying-Wei

    2015-01-01

    Recently, transition metal oxides, such as ruthenium oxide (RuO2), manganese dioxide (MnO2), nickel oxides (NiO) and cobalt oxide (Co3O4), have been widely investigated as electrode materials for pseudo-capacitors. In particular, these metal oxides with mesoporous structures have become very hot nanomaterials in the field of supercapacitors owing to their large specific surface areas and suitable pore size distributions. The high specific capacities of these mesoporous metal oxides are result...

  17. Periodically Arranged Arrays of Dendritic Pt Nanospheres Using Cage-Type Mesoporous Silica as a Hard Template.

    Science.gov (United States)

    Kani, Kenya; Malgras, Victor; Jiang, Bo; Hossain, Md Shahriar A; Alshehri, Saad M; Ahamad, Tansir; Salunkhe, Rahul R; Huang, Zhenguo; Yamauchi, Yusuke

    2018-01-04

    Dendritic Pt nanospheres of 20 nm diameter are synthesized by using a highly concentrated surfactant assembly within the large-sized cage-type mesopores of mesoporous silica (LP-FDU-12). After diluting the surfactant solution with ethanol, the lower viscosity leads to an improved penetration inside the mesopores. After Pt deposition followed by template removal, the arrangement of the Pt nanospheres is a replication from that of the mesopores in the original LP-FDU-12 template. Although it is well known that ordered LLCs can form on flat substrates, the confined space inside the mesopores hinders surfactant self-organization. Therefore, the Pt nanospheres possess a dendritic porous structure over the entire area. The distortion observed in some nanospheres is attributed to the close proximity existing between neighboring cage-type mesopores. This new type of nanoporous metal with a hierarchical architecture holds potential to enhance substance diffusivity/accessibility for further improvement of catalytic activity. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Surfactant-assisted sol gel preparation of high-surface area mesoporous TiO2 nanocrystalline Li-ion battery anodes

    International Nuclear Information System (INIS)

    Casino, S.; Di Lupo, F.; Francia, C.; Tuel, A.; Bodoardo, S.; Gerbaldi, C.

    2014-01-01

    Highlights: • Mesoporous TiO 2 nanocrystalline lithium battery anodes with tunable morphology. • Simple sol–gel technique using different cationic surfactants is adopted. • Textural/morphological characteristics define the electrochemical behaviour. • TiO 2 anatase using C16TAB exhibits stable performance after 200 cycles. • It shows promising prospects as high-voltage safe Li-ion battery anode. - Abstract: We here investigate the physico-chemical/morphological characteristics and cycling behaviour of several kinds of nanocrystalline TiO 2 Li-ion battery anodes selectively prepared through a simple sol–gel strategy based on a low-cost titanium oxysulfate precursor, by mediation of different cationic surfactants having different features (e.g., chain lengths, counter ion, etc.): i.e., cetyl-trimethylammonium bromide (CTAB), cetyl-trimethylammonium chloride (CTAC), benzalkonium chloride (BC) or octadecyl-trimethyl ammonium bromide (C 18 TAB). X-ray diffraction profiles reveal single phase anatase having good correspondence with the reference pattern when using short chain CTAB, while in the other cases the presence of chloride and/or an increased chain length affect the purity of the samples. FESEM analysis reveal nanosized particles forming cauliflower-like aggregates. TiO 2 materials demonstrate mesoporous characteristics and large specific surface area ranging from 250 to 30 m 2 g −1 . Remarkably stable electrode performance are achieved by appropriately selecting the cationic surfactant and the surfactant/precursor ratio. Detailed analysis is provided on the effect of the reaction conditions upon the formation of mesoporous crystalline titania enlightening new directions for the development of high performing lithium storage electrodes by a simple and low cost sol–gel strategy

  19. Highly efficient enrichment of phosphopeptides from HeLa cells using hollow magnetic macro/mesoporous TiO2 nanoparticles.

    Science.gov (United States)

    Hong, Yayun; Zhan, Qiliang; Pu, Chenlu; Sheng, Qianying; Zhao, Hongli; Lan, Minbo

    2018-09-01

    In this work, hollow magnetic macro/mesoporous TiO 2 nanoparticles (denoted as Fe 3 O 4 @H-fTiO 2 ) were synthesized by a facile "hydrothermal etching assisted crystallization" route to improve the phosphopeptide enrichment efficiency. The porous nanostructure of TiO 2 shell and large hollow space endowed the Fe 3 O 4 @H-fTiO 2 with a high surface area (144.71 m 2 g -1 ) and a large pore volume (0.52 cm 3 g -1 ), which could provide more affinity sites for phosphopeptide enrichment. Besides, the large pore size of TiO 2 nanosheets and large hollow space could effectively prevent the "shadow effect", thereby facilitating the diffusion and release of phosphopeptides. Compared with the hollow magnetic mesoporous TiO 2 with small and deep pores (denoted as Fe 3 O 4 @H-mTiO 2 ) and solid magnetic macro/mesoporous TiO 2 , the Fe 3 O 4 @H-fTiO 2 nanoparticles showed a better selectivity (molar ratio of α-casein/BSA up to 1:10000) and a higher sensitivity (0.2 fmol/μL α-casein) for phosphopeptide enrichment. Furthermore, 1485 unique phosphopeptides derived from 660 phosphoproteins were identified from HeLa cell extracts after enrichment with Fe 3 O 4 @H-fTiO 2 nanoparticles, further demonstrating that the Fe 3 O 4 @H-fTiO 2 nanoparticles had a high-efficiency performance for phosphopeptide enrichment. Taken together, the Fe 3 O 4 @H-fTiO 2 nanoparticles will have unique advantages in phosphoproteomics analysis. Copyright © 2018 Elsevier B.V. All rights reserved.

  20. Highly Sensitive Ethanol Chemical Sensor Based on Novel Ag-Doped Mesoporous α-Fe2O3 Prepared by Modified Sol-Gel Process

    Science.gov (United States)

    Alqahtani, Moteb M.; Ali, Atif M.; Harraz, Farid A.; Faisal, M.; Ismail, Adel A.; Sayed, Mahmoud A.; Al-Assiri, M. S.

    2018-05-01

    Mesoporous α-Fe2O3 has been synthesized via a simple sol-gel procedure in the presence of Pluronic (F-127) triblock copolymer as structure directing agent. Silver (Ag) nanoparticles were deposited onto α-Fe2O3 matrix by the photochemical reduction approach. Morphological analysis revealed the formation of Ag nanoparticles with small sizes < 20 nm onto the mesoporous structure of α-Fe2O3 possessing < 50 nm semi-spherical shape. The XRD, FTIR, Raman, UV-vis, PL, and N2 sorption isotherm studies confirmed the high crystallinity, mesoporosity, and optical characteristics of the synthesized product. The electrochemical sensing toward liquid ethanol has been performed using the current devolved Ag/α-Fe2O3-modified glassy carbon electrode (GCE) by cyclic voltammetry ( CV) and current potential ( I-V) techniques, and the obtained results were compared with bare GCE or pure α-Fe2O3. Mesoporous Ag/α-Fe2O3 was found to largely enhance the sensor sensitivity and it exhibited excellent sensing characteristics during the precision detection of low concentrations of ethanol. High and reproducible sensitivity of 41.27 μAmM- 1 cm- 2 at lower ethanol concentration region (0.05 to 0.8 mM) and 2.93 μAmM- 1 cm- 2 at higher concentration zone (0.8 to 15 mM), with a limit of detection (LOD) of 15.4 μM have been achieved. Investigation on reaction kinetics revealed a characteristic behavior of mixed surface and diffusion-controlled processes. Detailed sensing studies revealed also that the sensitivity toward ethanol was higher than that of methanol or isopropanol. With further effort in developing the synthesis and fabrication approaches, a proper utility for the current proposed protocol for fabricating a better sensor device performance is possible.

  1. Surfactant-assisted sol gel preparation of high-surface area mesoporous TiO{sub 2} nanocrystalline Li-ion battery anodes

    Energy Technology Data Exchange (ETDEWEB)

    Casino, S. [GAME Lab, Department of Applied Science and Technology – DISAT, Institute of Chemistry, Politecnico di Torino, C.so Duca degli Abruzzi 24, 10129 Torino (Italy); Di Lupo, F., E-mail: francesca.dilupo@polito.it [GAME Lab, Department of Applied Science and Technology – DISAT, Institute of Chemistry, Politecnico di Torino, C.so Duca degli Abruzzi 24, 10129 Torino (Italy); Francia, C. [GAME Lab, Department of Applied Science and Technology – DISAT, Institute of Chemistry, Politecnico di Torino, C.so Duca degli Abruzzi 24, 10129 Torino (Italy); Tuel, A. [IRCELYON, Institut de Recherches sur la Catalyse et l’environnement de Lyon, UMR 5256, CNRS-Université de Lyon 1, 2 Avenue Albert Einstein, 69626 Villeurbanne Cedex (France); Bodoardo, S. [GAME Lab, Department of Applied Science and Technology – DISAT, Institute of Chemistry, Politecnico di Torino, C.so Duca degli Abruzzi 24, 10129 Torino (Italy); Gerbaldi, C., E-mail: claudio.gerbaldi@polito.it [GAME Lab, Department of Applied Science and Technology – DISAT, Institute of Chemistry, Politecnico di Torino, C.so Duca degli Abruzzi 24, 10129 Torino (Italy)

    2014-05-01

    Highlights: • Mesoporous TiO{sub 2} nanocrystalline lithium battery anodes with tunable morphology. • Simple sol–gel technique using different cationic surfactants is adopted. • Textural/morphological characteristics define the electrochemical behaviour. • TiO{sub 2} anatase using C16TAB exhibits stable performance after 200 cycles. • It shows promising prospects as high-voltage safe Li-ion battery anode. - Abstract: We here investigate the physico-chemical/morphological characteristics and cycling behaviour of several kinds of nanocrystalline TiO{sub 2} Li-ion battery anodes selectively prepared through a simple sol–gel strategy based on a low-cost titanium oxysulfate precursor, by mediation of different cationic surfactants having different features (e.g., chain lengths, counter ion, etc.): i.e., cetyl-trimethylammonium bromide (CTAB), cetyl-trimethylammonium chloride (CTAC), benzalkonium chloride (BC) or octadecyl-trimethyl ammonium bromide (C{sub 18}TAB). X-ray diffraction profiles reveal single phase anatase having good correspondence with the reference pattern when using short chain CTAB, while in the other cases the presence of chloride and/or an increased chain length affect the purity of the samples. FESEM analysis reveal nanosized particles forming cauliflower-like aggregates. TiO{sub 2} materials demonstrate mesoporous characteristics and large specific surface area ranging from 250 to 30 m{sup 2} g{sup −1}. Remarkably stable electrode performance are achieved by appropriately selecting the cationic surfactant and the surfactant/precursor ratio. Detailed analysis is provided on the effect of the reaction conditions upon the formation of mesoporous crystalline titania enlightening new directions for the development of high performing lithium storage electrodes by a simple and low cost sol–gel strategy.

  2. Synthesis of Pyrimethanil-Loaded Mesoporous Silica Nanoparticles and Its Distribution and Dissipation in Cucumber Plants.

    Science.gov (United States)

    Zhao, Pengyue; Cao, Lidong; Ma, Dukang; Zhou, Zhaolu; Huang, Qiliang; Pan, Canping

    2017-05-16

    Mesoporous silica nanoparticles are used as pesticide carries in plants, which has been considered as a novel method to reduce the indiscriminate use of conventional pesticides. In the present work, mesoporous silica nanoparticles with particle diameters of 200-300 nm were synthesized in order to obtain pyrimethanil-loaded nanoparticles. The microstructure of the nanoparticles was observed by scanning electron microscopy. The loading content of pyrimethanil-loaded nanoparticles was investigated. After treatment on cucumber leaves, the concentrations of pyrimethanil were determined in different parts of cucumber over a period of 48 days using high performance liquid chromatography tandem mass spectrometry. It was shown that the pyrimethanil-loaded mesoporous silica nanoparticles might be more conducive to acropetal, rather than basipetal, uptake, and the dosage had almost no effect on the distribution and dissipation rate in cucumber plants. The application of the pesticide-loaded nanoparticles in leaves had a low risk of pyrimethanil accumulating in the edible part of the plant.

  3. Synthesis, characterization, and catalytic properties of stable mesoporous molecular sieve MCM-41 prepared from zeolite mordenite

    International Nuclear Information System (INIS)

    Wang Shan; Dou Tao; Li Yuping; Zhang Ying; Li Xiaofeng; Yan Zichun

    2004-01-01

    Mesoporous molecular sieves (denoted as M-MCM-41) with ordered hexagonal structure have been successfully synthesized from the assembly of precursors from preformed zeolite Mordenite with CTAB surfactant micelle in alkaline media. The samples were characterized by XRD, N 2 adsorption, IR and DTG. The materials exhibit highly hydrothermal stability, as compared with conventional MCM-41. Characterization results indicate that the mesoporous walls of M-MCM-41 contain the secondary building units similar to those in microporous crystal of zeolite Mordenite. In catalytic dealkylation of C10 + aromatic hydrocarbon, M-MCM-41 shows higher activities in comparison with Mordenite and MCM-41, which would be ascribed to the combination of advantages of both MCM-41 (large pores) and Mordenite (strong acidity). Furthermore, this synthesis strategy could be used as a new general method for the preparation of hydrothermally stable mesoporous aluminosilicate materials under alkaline conditions

  4. Synthesis and characterization of nanoparticulate MnS within the pores of mesoporous silica

    International Nuclear Information System (INIS)

    Barry, Louse; Copley, Mark; Holmes, Justin D.; Otway, David J.; Kazakova, Olga; Morris, Michael A.

    2007-01-01

    Mesoporous silica was loaded with nanoparticulate MnS via a simple post-synthesis treatment. The mesoporous material that still contained surfactant was passivated to prevent MnS formation at the surface. The surfactant was extracted and a novel manganese ethylxanthate was used to impregnate the pore network. This precursor thermally decomposes to yield MnS particles that are smaller or equal to the pore size. The particles exhibit all three common polymorphs. The passivation treatment is most effective at lower loadings because at the highest loadings (SiO 2 :MnS molar ratio of 6:1) large particles (>50 nm) form at the exterior of the mesoporous particles. The integrity of the mesoporous network is maintained through the preparation and high order is maintained. The MnS particles exhibit unexpected ferromagnetism at low temperatures. Strong luminescence of these samples is observed and this suggests that they may have a range of important application areas. - Graphical abstract: A novel manganese ethylxanthate precursor was used to impregnate the pore network of mesoporous silica and was decomposed to yield MnS particles smaller or equal to the pore size. The particles exhibit all three common polymorphs, demonstrate unexpected ferromagnetism at low temperatures and display a strong luminescence

  5. Biodegradable Magnetic Silica@Iron Oxide Nanovectors with Ultra-Large Mesopores for High Protein Loading, Magnetothermal Release, and Delivery

    KAUST Repository

    Omar, Haneen

    2016-11-29

    The delivery of large cargos of diameter above 15 nm for biomedical applications has proved challenging since it requires biocompatible, stably-loaded, and biodegradable nanomaterials. In this study, we describe the design of biodegradable silica-iron oxide hybrid nanovectors with large mesopores for large protein delivery in cancer cells. The mesopores of the nanomaterials spanned from 20 to 60 nm in diameter and post-functionalization allowed the electrostatic immobilization of large proteins (e.g. mTFP-Ferritin, ~ 534 kDa). Half of the content of the nanovectors was based with iron oxide nanophases which allowed the rapid biodegradation of the carrier in fetal bovine serum and a magnetic responsiveness. The nanovectors released large protein cargos in aqueous solution under acidic pH or magnetic stimuli. The delivery of large proteins was then autonomously achieved in cancer cells via the silica-iron oxide nanovectors, which is thus a promising for biomedical applications.

  6. Mesoporous ZnO-NiO architectures for use in a high-performance nonenzymatic glucose sensor

    International Nuclear Information System (INIS)

    Liu, Yuanying; Wei, Chengzhen; Hao, Mingming; Zheng, Shasha; Pang, Huan; Zheng, Mingbo

    2014-01-01

    Mesoporous ZnO-NiO architectures were prepared by thermal annealing of zinc-nickel hydroxycarbonate composites. The resulting architectures are shown to be assembled by many mesoporous nanosheets, and this results in a large surface area and a strong synergy between the ZnO and NiO nanoparticles. The material obtained by annealing at 400 °C was used as an electrode that responds to glucose over a wide concentration range (from 0.5 μM to 6.4 mM), with a detection limit as low as 0.5 μM, fast response time (<3 s), and good sensitivity (120.5 μA · mM −1  · cm −2 ). (author)

  7. Designing advanced functional periodic mesoporous organosilicas for biomedical applications

    Directory of Open Access Journals (Sweden)

    Dolores Esquivel

    2014-03-01

    Full Text Available Periodic mesoporous organosilicas (PMOs, reported for the first time in 1999, constitute a new branch of organic-inorganic hybrid materials with high-ordered structures, uniform pore size and homogenous distribution of organic bridges into a silica framework. Unlike conventional mesoporous silicas, these materials offer the possibility to adjust the surface (hydrophilicity/hydrophobicity and physical properties (morphology, porosity as well as their mechanical stability through the incorporation of different functional organic moieties in their pore walls. A broad variety of PMOs has been designed for their subsequent application in many fields. More recently, PMOs have attracted growing interest in emerging areas as biology and biomedicine. This review provides a comprehensive overview of the most recent breakthroughs achieved for PMOs in biological and biomedical applications.

  8. Direct large-scale synthesis of 3D hierarchical mesoporous NiO microspheres as high-performance anode materials for lithium ion batteries.

    Science.gov (United States)

    bai, Zhongchao; Ju, Zhicheng; Guo, Chunli; Qian, Yitai; Tang, Bin; Xiong, Shenglin

    2014-03-21

    Hierarchically porous materials are an ideal material platform for constructing high performance Li-ion batteries (LIBs), offering great advantages such as large contact area between the electrode and the electrolyte, fast and flexible transport pathways for the electrolyte ions and the space for buffering the strain caused by repeated Li insertion/extraction. In this work, NiO microspheres with hierarchically porous structures have been synthesized via a facile thermal decomposition method by only using a simple precursor. The superstructures are composed of nanocrystals with high specific surface area, large pore volume, and broad pore size distribution. The electrochemical properties of 3D hierarchical mesoporous NiO microspheres were examined by cyclic voltammetry and galvanostatic charge-discharge studies. The results demonstrate that the as-prepared NiO nanospheres are excellent electrode materials in LIBs with high specific capacity, good retention and rate performance. The 3D hierarchical mesoporous NiO microspheres can retain a reversible capacity of 800.2 mA h g(-1) after 100 cycles at a high current density of 500 mA g(-1).

  9. Synthesis of a mesoporous single crystal Ga2O3 nanoplate with improved photoluminescence and high sensitivity in detecting CO.

    Science.gov (United States)

    Yan, Shicheng; Wan, Lijuan; Li, Zhaosheng; Zhou, Yong; Zou, Zhigang

    2010-09-14

    A new approach is proposed to synthesize a mesoporous single crystal Ga(2)O(3) nanoplate by heating a single crystal nanoplate of GaOOH, which involves an ion exchange between KGaO(2) and CH(3)COOH at room temperature for the formation of GaOOH and pseudomorphic and topotactic phase transformation from GaOOH to Ga(2)O(3).

  10. A simple synthetic route of N-doped mesoporous carbon derived from casein extracted with cobalt ions for high rate performance supercapacitors

    International Nuclear Information System (INIS)

    Jia, Shaopei; Wang, Yanhui; Tian, Pengfei; Zhou, Shuyu; Cai, Haixia; Gao, Hongwei; Zang, Jianbing

    2017-01-01

    Highlights: •NMC is prepared by pyrolysis of cobalt-containing casein. •Cobalt-containing casein is extracted from the pure milk by cobalt ions. •The cobalt element increases the specific surface area and the N doping amount. •NMC exhibits high specific capacitance, high rate capability, and excellent cycling stability. -- Abstract: Nitrogen-doped mesoporous carbon (NMC) was synthesized via pyrolysis of cobalt-containing casein obtained by extraction from pure milk with the auxiliary of cobalt ions. The cobalt element in casein promoted specific surface area and N element doping amount of casein-derived porous carbon. The N-doped porous carbon obtained by carbonization at 800 °C (NPC-800) possessed a specific surface area of ∼886.7 m 2 g −1 , and the mesoporous size was centered at 2.7 and 7 nm. X-ray photoelectron spectroscopy analysis showed that the nitrogen content of NPC-800 was 3.29 at%. The NPC-800 was explored as a symmetric supercapacitor, which exhibited specific capacity of 380 F g −1 at a current density of 0.5 A g −1 , 218 F g −1 at a current density of 20 A g −1 , and high capacitance retention of 91.3% after charging/discharging 5,000 cycles.

  11. Lightweight, Mesoporous, and Highly Absorptive All-Nanofiber Aerogel for Efficient Solar Steam Generation.

    Science.gov (United States)

    Jiang, Feng; Liu, He; Li, Yiju; Kuang, Yudi; Xu, Xu; Chen, Chaoji; Huang, Hao; Jia, Chao; Zhao, Xinpeng; Hitz, Emily; Zhou, Yubing; Yang, Ronggui; Cui, Lifeng; Hu, Liangbing

    2018-01-10

    The global fresh water shortage has driven enormous endeavors in seawater desalination and wastewater purification; among these, solar steam generation is effective in extracting fresh water by efficient utilization of naturally abundant solar energy. For solar steam generation, the primary focus is to design new materials that are biodegradable, sustainable, of low cost, and have high solar steam generation efficiency. Here, we designed a bilayer aerogel structure employing naturally abundant cellulose nanofibrils (CNFs) as basic building blocks to achieve sustainability and biodegradability as well as employing a carbon nanotube (CNT) layer for efficient solar utilization with over 97.5% of light absorbance from 300 to 1200 nm wavelength. The ultralow density (0.0096 g/cm 3 ) of the aerogel ensures that minimal material is required, reducing the production cost while at the same time satisfying the water transport and thermal-insulation requirements due to its highly porous structure (99.4% porosity). Owing to its rationally designed structure and thermal-regulation performance, the bilayer CNF-CNT aerogel exhibits a high solar-energy conversion efficiency of 76.3% and 1.11 kg m -2 h -1 at 1 kW m -2 (1 Sun) solar irradiation, comparable or even higher than most of the reported solar steam generation devices. Therefore, the all-nanofiber aerogel presents a new route for designing biodegradable, sustainable, and scalable solar steam generation devices with superb performance.

  12. Partial hydrogenation of alkynes on highly selective nano-structured mesoporous silica MCM-41 composite catalyst

    International Nuclear Information System (INIS)

    Kojoori, R.K.

    2016-01-01

    In this research, we have developed a silica MCM-41/Metformin/Pd (II) nano composite catalyst for the selective hydrogenation of alkynes to the corresponding (Z)-alkenes under a mild condition of atmospheric pressure and room temperature. Firstly, functionalized Si-MCM-41 metformin catalyst with the optimum performance was prepared. Then, the synthesized catalyst was elucidated by X-ray powder diffraction, BET surface area, FT-IR spectrophotometer, Scanning electron microscopy (SEM) and Transmission electron microscopy (TEM) and applied in partial hydrogenation of different alkynes, with high selectivity and high yield. The products were characterized by 1H-NMR, 13C-NMR, FT-IR, and Mass Spectrometry (MS) that strongly approved the (Z)-double bond configuration of produced alkenes. This prepared catalyst is competitive with the best palladium catalysts known for the selective liquid phase hydrogenation of alkynes and can be easily recovered and regenerated with keeping high activity and selectivity over at least three cycles with a simple regeneration procedure. (author)

  13. Mesoporous hydroxyapatite: Preparation, drug adsorption, and release properties

    Energy Technology Data Exchange (ETDEWEB)

    Gu, Lina; He, Xiaomei; Wu, Zhenyu, E-mail: zhenyuwuhn@sina.com

    2014-11-14

    Mesoporous hydroxyapatite (HA) was synthesized through gas–liquid chemical precipitation method at ambient temperature without any template. Structure, morphology and pore size distribution of HA were analyzed via X-ray powder diffraction, scanning electron microscopy, transmission electron microscopy, high-resolution electron microscopy and N{sub 2} adsorption/desorption. The chemotherapeutic agent doxorubicin (DOX) was used to investigate the drug adsorption and release behavior of HA. The kinetics of DOX adsorption on HA followed the pseudo-second-order rate expression. Adsorption isotherms at various temperatures were obtained, and the equilibrium data fitted the Langmuir model. The values of thermodynamic parameters (Gibbs free energy, entropy, and enthalpy changes) demonstrated that the adsorption process was spontaneous and endothermic. In vitro pH-responsive (pH = 7.4, 5.8) controlled release was investigated. DOX-loaded HA showed a slow, long-term, and steady release rate. The release rate at pH5.8 was larger than that at pH7.4. Consequently, the as-prepared mesoporous HA has potential applications in controlled drug delivery systems. - Highlights: • Mesoporous HA was synthesized by a simple precipitation method without any template. • The kinetics of adsorption followed the pseudo-second-order rate expression. • Thermodynamics investigation showed that adsorption was spontaneous and endothermic. • DOX-loaded HA showed a long-term, steady, and pH-controlled release rate.

  14. Synthesis of Ru nanoparticles confined in magnesium oxide-modified mesoporous alumina and their enhanced catalytic performance during ammonia decomposition

    KAUST Repository

    Tan, Hua

    2012-09-01

    In this work, Ru nanoparticles confined in the channels of ordered mesoporous alumina (MA) and magnesium oxide-modified ordered MA are prepared for the first time via a two-solvent technique, combined with the amorphous citrate route. Structural characterizations reveal that uniform 2-3 nm Ru nanoparticles are highly dispersed in the blockage-free channels of mesoporous supports. The Ru nanoparticles confined in MA modified with 20% molar ratio magnesium oxide exhibited a high catalytic activity and stability during ammonia decomposition due to the optimized particle size, basic support, lack of chlorine, and confined space provided by the channels of the mesoporous supports. © 2012 Elsevier B.V. All rights reserved.

  15. Synthesis of Ru nanoparticles confined in magnesium oxide-modified mesoporous alumina and their enhanced catalytic performance during ammonia decomposition

    KAUST Repository

    Tan, Hua; Li, Kun; Sioud, Salim; Cha, Dong Kyu; Amad, Maan H.; Hedhili, Mohamed N.; Al-Talla, Zeyad

    2012-01-01

    In this work, Ru nanoparticles confined in the channels of ordered mesoporous alumina (MA) and magnesium oxide-modified ordered MA are prepared for the first time via a two-solvent technique, combined with the amorphous citrate route. Structural characterizations reveal that uniform 2-3 nm Ru nanoparticles are highly dispersed in the blockage-free channels of mesoporous supports. The Ru nanoparticles confined in MA modified with 20% molar ratio magnesium oxide exhibited a high catalytic activity and stability during ammonia decomposition due to the optimized particle size, basic support, lack of chlorine, and confined space provided by the channels of the mesoporous supports. © 2012 Elsevier B.V. All rights reserved.

  16. Spontaneous Synthesis of Highly Crystalline TiO2 Compact/Mesoporous Stacked Films by a Low-Temperature Steam-Annealing Method for Efficient Perovskite Solar Cells.

    Science.gov (United States)

    Sanehira, Yoshitaka; Numata, Youhei; Ikegami, Masashi; Miyasaka, Tsutomu

    2018-05-23

    Highly crystalline TiO 2 nanostructured films were synthesized by a simple steam treatment of a TiCl 4 precursor film under a saturated water vapor atmosphere at 125 °C, here referred to as the steam-annealing method. In a single TiO 2 film preparation step, a bilayer structure comprising a compact bottom layer and a mesoporous surface layer was formed. The mesoporous layer was occupied by bipyramidal nanoparticles, with a composite phase of anatase and brookite crystals. Despite the low-temperature treatment process, the crystallinity of the TiO 2 film was high, comparable with that of the TiO 2 film sintered at 500 °C. The compact double-layered TiO 2 film was applied to perovskite solar cells (PSCs) as an electron-collecting layer. The PSC exhibited a maximum power conversion efficiency (PCE) of 18.9% with an open-circuit voltage ( V OC ) of 1.15 V. The PCE and V OC were higher than those of PSCs using a TiO 2 film formed by 500 °C sintering.

  17. Hierarchical Mesoporous NiO/MnO2@PANI Core-Shell Microspheres, Highly Efficient and Stable Bifunctional Electrocatalysts for Oxygen Evolution and Reduction Reactions.

    Science.gov (United States)

    He, Junkai; Wang, Mingchao; Wang, Wenbo; Miao, Ran; Zhong, Wei; Chen, Sheng-Yu; Poges, Shannon; Jafari, Tahereh; Song, Wenqiao; Liu, Jiachen; Suib, Steven L

    2017-12-13

    We report on the new facile synthesis of mesoporous NiO/MnO 2 in one step by modifying inverse micelle templated UCT (University of Connecticut) methods. The catalyst shows excellent electrocatalytic activity and stability for both the oxygen evolution reaction (OER) and the oxygen reduction reaction (ORR) in alkaline media after further coating with polyaniline (PANI). For electrochemical performance, the optimized catalyst exhibits a potential gap, ΔE, of 0.75 V to achieve a current of 10 mA cm -2 for the OER and -3 mA cm -2 for the ORR in 0.1 M KOH solution. Extensive characterization methods were applied to investigate the structure-property of the catalyst for correlations with activity (e.g., XRD, BET, SEM, HRTEM, FIB-TEM, XPS, TGA, and Raman). The high electrocatalytic activity of the catalyst closely relates to the good electrical conductivity of PANI, accessible mesoporous structure, high surface area, as well as the synergistic effect of the specific core-shell structure. This work opens a new avenue for the rational design of core-shell structure catalysts for energy conversion and storage applications.

  18. Triblock-Terpolymer-Directed Self-Assembly of Mesoporous TiO2: High-Performance Photoanodes for Solid-State Dye-Sensitized Solar Cells

    KAUST Repository

    Docampo, Pablo

    2012-04-30

    A new self-assembly platform for the fast and straightforward synthesis of bicontinuous, mesoporous TiO 2 films is presented, based on the triblock terpolymer poly(isoprene - b - styrene - b - ethylene oxide). This new materials route allows the co-assembly of the metal oxide as a fully interconnected minority phase, which results in a highly porous photoanode with strong advantages over the state-of-the-art nanoparticle-based photoanodes employed in solidstate dye-sensitized solar cells. Devices fabricated through this triblock terpolymer route exhibit a high availability of sub-bandgap states distributed in a narrow and low enough energy band, which maximizes photoinduced charge generation from a state-of-the-art organic dye, C220. As a consequence, the co-assembled mesoporous metal oxide system outperformed the conventional nanoparticle-based electrodes fabricated and tested under the same conditions, exhibiting solar power-conversion efficiencies of over 5%. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Triblock-Terpolymer-Directed Self-Assembly of Mesoporous TiO2: High-Performance Photoanodes for Solid-State Dye-Sensitized Solar Cells

    KAUST Repository

    Docampo, Pablo; Stefik, Morgan; Guldin, Stefan; Gunning, Robert; Yufa, Nataliya A.; Cai, Ning; Wang, Peng; Steiner, Ullrich; Wiesner, Ulrich; Snaith, Henry J.

    2012-01-01

    A new self-assembly platform for the fast and straightforward synthesis of bicontinuous, mesoporous TiO 2 films is presented, based on the triblock terpolymer poly(isoprene - b - styrene - b - ethylene oxide). This new materials route allows the co-assembly of the metal oxide as a fully interconnected minority phase, which results in a highly porous photoanode with strong advantages over the state-of-the-art nanoparticle-based photoanodes employed in solidstate dye-sensitized solar cells. Devices fabricated through this triblock terpolymer route exhibit a high availability of sub-bandgap states distributed in a narrow and low enough energy band, which maximizes photoinduced charge generation from a state-of-the-art organic dye, C220. As a consequence, the co-assembled mesoporous metal oxide system outperformed the conventional nanoparticle-based electrodes fabricated and tested under the same conditions, exhibiting solar power-conversion efficiencies of over 5%. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Triblock-terpolymer-directed self-assembly of mesoporous TiO{sub 2}: High-performance photoanodes for solid-state dye-sensitized solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Docampo, Pablo; Gunning, Robert; Snaith, Henry J. [Clarendon Laboratory, Department of Physics, University of Oxford, Parks Road, Oxford OX1 3PU (United Kingdom); Stefik, Morgan; Wiesner, Ulrich [Department of Materials Science and Engineering, Cornell University, Ithaca, NY 14853 (United States); Guldin, Stefan; Yufa, Nataliya A.; Steiner, Ullrich [Department of Physics, University of Cambridge, J. J. Thomson Avenue, Cambridge CB3 0HE (United Kingdom); Cai, Ning; Wang, Peng [State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China)

    2012-06-15

    A new self-assembly platform for the fast and straightforward synthesis of bicontinuous, mesoporous TiO{sub 2} films is presented, based on the triblock terpolymer poly(isoprene-b-styrene-b-ethylene oxide). This new materials route allows the co-assembly of the metal oxide as a fully interconnected minority phase, which results in a highly porous photoanode with strong advantages over the state-of-the-art nanoparticle-based photoanodes employed in solid-state dye-sensitized solar cells. Devices fabricated through this triblock terpolymer route exhibit a high availability of sub-bandgap states distributed in a narrow and low enough energy band, which maximizes photoinduced charge generation from a state-of-the-art organic dye, C220. As a consequence, the co-assembled mesoporous metal oxide system outperformed the conventional nanoparticle-based electrodes fabricated and tested under the same conditions, exhibiting solar power-conversion efficiencies of over 5%. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  1. Airfoil noise computation use high-order schemes

    DEFF Research Database (Denmark)

    Zhu, Wei Jun; Shen, Wen Zhong; Sørensen, Jens Nørkær

    2007-01-01

    High-order finite difference schemes with at least 4th-order spatial accuracy are used to simulate aerodynamically generated noise. The aeroacoustic solver with 4th-order up to 8th-order accuracy is implemented into the in-house flow solver, EllipSys2D/3D. Dispersion-Relation-Preserving (DRP) fin...

  2. Minute-made and low carbon fingerprint microwave synthesis of high quality templated mesoporous silica

    KAUST Repository

    Chaignon, J.; Bouizi, Y.; Davin, L.; Calin, N.; Albela, B.; Bonneviot, L.

    2015-01-01

    © The Royal Society of Chemistry 2015. Hexagonal mesostructured templated silicas were produced in less than 10 minutes using an ultra-fast microwave assisted hydrothermal synthesis. Typically, 10 g can be prepared at once in a commercial microwave device usually devoted to analytical digestion. Undesired alcohol side-products were avoided using inexpensive water colloidal silica instead of silicon alkoxides as the silicon source. In comparison with classical heating activation, the absence of pore expansion and pore wall thickening even for synthesis temperatures as high as 190 °C evidenced that heat transfer and diffusion of matter had no time to take place. Comparison between the chemically extracted and calcined samples shows that the structure was better stabilized for autoclaving above 150 °C. However, a fast temperature ramping and final temperatures above 180 °C were required to sear structures of the highest quality comparable to that of the best conventional methods. This is rationalized by assuming a sequential flake-by-flake assembly of the pore-wall at the micelle palisade. Notably, tosylate counterions yielded better structural characteristics than bromide counterions and allowed better opportunities for surfactant recycling.

  3. Sonochemical synthesis and high lithium storage properties of ordered Co/CMK-3 nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Qiao, Hui, E-mail: huiqiaoz@163.com [Key Laboratory of Eco-textiles, Ministry of Education, Jiangnan University, Wuxi 214122 (China); Department of Electrical Engineering and Computer Sciences, South Dakota State University, Brookings, SD 57007 (United States); Xia, Zhaokang; Liu, Yanhua [Key Laboratory of Eco-textiles, Ministry of Education, Jiangnan University, Wuxi 214122 (China); Cui, Rongrong, E-mail: cuirong3243@sina.com [Key Laboratory of Eco-textiles, Ministry of Education, Jiangnan University, Wuxi 214122 (China); Fei, Yaqian; Cai, Yibing; Wei, Qufu [Key Laboratory of Eco-textiles, Ministry of Education, Jiangnan University, Wuxi 214122 (China); Yao, Qingxia [School of Chemistry and Chemical Engineering, Liaocheng University, Liaocheng, 252000 (China); Qiao, Qiquan, E-mail: qiquan.qiao@sdstate.edu [Department of Electrical Engineering and Computer Sciences, South Dakota State University, Brookings, SD 57007 (United States)

    2017-04-01

    Graphical abstract: A novel ordered Co/CMK-3 nanocomposite was successfully synthesized via the sonochemical method followed by carbonization process. The lithium storage properties demonstrated that ordered Co/CMK-3 nanocomposites possessed high reversible capacity and cycling stability. Moreover, the ordered Co/CMK-3 nanocomposites electrode also exhibits high capacity at higher charge/discharge rate. - Highlights: • A novel ordered Co/CMK-3 nanocomposite was successfully synthesized via the sonochemical method followed by carbonization process. • The lithium storage properties shows that the ordered Co/CMK-3 nanocomposites exhibit a large reversible capacity and good cycle stability with the capacity of 720 mAh g{sup −1} after 50 cycles. • The ordered Co/CMK-3 nanocomposites also showed high capacity at higher discharge and charge rate. - Abstract: A novel ordered Co/CMK-3 nanocomposite was successfully synthesized via the sonochemical method followed by carbonization process. The ordered Co/CMK-3 nanocomposite were characterized by X-ray diffraction, transmission electron microscopy and N{sub 2} adsorption–desorption analysis techniques. The lithium storage properties shows that the Co/CMK-3 nanocomposites exhibit a large reversible capacity and good cycle stability with the capacity of 720 mAh g{sup −1} after 50 cycles at a current rate of 50 mA g{sup −1}, much higher than that of original CMK-3 electrode. The Co/CMK-3 nanocomposites also demonstrates an excellent rate capability with capacity of 479 mAh g{sup −1} even at a current density of 1000 mA g{sup −1} after 50 cycles. The improved lithium storage properties of ordered Co/CMK-3 nanocomposites can be attributed to the CMK-3 could restrain the aggregation of Co nanoparticles, the large surface area of the mesopores in which the Co nanoparticles are formed, as well as presence of Co which played the role of catalyst could promote the lithium storage reaction.

  4. Sonochemical synthesis and high lithium storage properties of ordered Co/CMK-3 nanocomposites

    International Nuclear Information System (INIS)

    Qiao, Hui; Xia, Zhaokang; Liu, Yanhua; Cui, Rongrong; Fei, Yaqian; Cai, Yibing; Wei, Qufu; Yao, Qingxia; Qiao, Qiquan

    2017-01-01

    Graphical abstract: A novel ordered Co/CMK-3 nanocomposite was successfully synthesized via the sonochemical method followed by carbonization process. The lithium storage properties demonstrated that ordered Co/CMK-3 nanocomposites possessed high reversible capacity and cycling stability. Moreover, the ordered Co/CMK-3 nanocomposites electrode also exhibits high capacity at higher charge/discharge rate. - Highlights: • A novel ordered Co/CMK-3 nanocomposite was successfully synthesized via the sonochemical method followed by carbonization process. • The lithium storage properties shows that the ordered Co/CMK-3 nanocomposites exhibit a large reversible capacity and good cycle stability with the capacity of 720 mAh g"−"1 after 50 cycles. • The ordered Co/CMK-3 nanocomposites also showed high capacity at higher discharge and charge rate. - Abstract: A novel ordered Co/CMK-3 nanocomposite was successfully synthesized via the sonochemical method followed by carbonization process. The ordered Co/CMK-3 nanocomposite were characterized by X-ray diffraction, transmission electron microscopy and N_2 adsorption–desorption analysis techniques. The lithium storage properties shows that the Co/CMK-3 nanocomposites exhibit a large reversible capacity and good cycle stability with the capacity of 720 mAh g"−"1 after 50 cycles at a current rate of 50 mA g"−"1, much higher than that of original CMK-3 electrode. The Co/CMK-3 nanocomposites also demonstrates an excellent rate capability with capacity of 479 mAh g"−"1 even at a current density of 1000 mA g"−"1 after 50 cycles. The improved lithium storage properties of ordered Co/CMK-3 nanocomposites can be attributed to the CMK-3 could restrain the aggregation of Co nanoparticles, the large surface area of the mesopores in which the Co nanoparticles are formed, as well as presence of Co which played the role of catalyst could promote the lithium storage reaction.

  5. A flexible mesoporous Li4Ti5O12-rGO nanocomposite film as free-standing anode for high rate lithium ion batteries

    Science.gov (United States)

    Zhu, Kunxu; Gao, Hanyang; Hu, Guoxin

    2018-01-01

    Advanced flexible electrode is crucial in the development of flexible energy storage devices for emerging wearable and portable electronics. Herein, a free-standing flexible mesoporous Li4Ti5O12-rGO (LTO-rGO) nanocomposite film is rationally designed and fabricated for lithium ion batteries (LIBs). This efficient synthesis involves the growth of lithium titanate hydrate (LTH) precursors on the graphene oxide (GO) by a hydrothermal reaction, assembly into LTH-GO film by vacuum filtration with some extra GO added, and subsequent conversion into LTO-rGO nanocomposite film through calcination. When rGO content in the LTO-rGO film is set, the addition sequence of GO is found to affect its textural and mechanical properties. The resultant free-standing LTO-rGO electrode, taking advantages of high Li4Ti5O12 loading of 73.9%, mesoporous layer-stacked channels with good electron/ion conductivity, good mechanical strength, and enlarged electrode/electrolyte contact area, delivers excellent electrochemical performance (e.g., specific capacity of 135.4 mAh g-1 at 40 C) over the electrode of conventional configuration. Moreover, no organic but all inorganic reagents are used in the synthesis, offering an eco-friendly, cost-efficient, and easily scalable way to fabricate binder-free flexible electrode for LIBs.

  6. Mesoporous anatase TiO2/reduced graphene oxide nanocomposites: A simple template-free synthesis and their high photocatalytic performance

    International Nuclear Information System (INIS)

    Zhou, Qi; Zhong, Yong-Hui; Chen, Xing; Huang, Xing-Jiu; Wu, Yu-Cheng

    2014-01-01

    Graphical abstract: - Highlights: • Mesoporous TiO 2 nanoparticles with anatase phase were assembled on reduced graphene oxide via a template-free one-step hydrothermal method. • The TiO 2 /rGO nanocomposites have better adsorption capacity and photocatalytic degradation efficiency for dyes removal. • Improved dye adsorption and photogenerated charge separation are responsible for enhanced activity. - Abstract: Mesoporous anatase phase TiO 2 was assembled on reduced graphene oxide (rGO) using a template-free one-step hydrothermal process. The nanocomposites were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and Brunauer–Emmett–Teller (BET) surface area. Morphology of TiO 2 was related to the content of graphene oxide. TiO 2 /rGO nanocomposites exhibited excellent photocatalytic activity for the photo-degradation of methyl orange. The degradation rate was 4.5 times greater than that of pure TiO 2 nanoparticles. This difference was attributed to the thin two-dimensional graphene sheet. The graphene sheet had a large surface area, high adsorption capacity, and acted as a good electron acceptor for the transfer of photo-generated electrons from the conduction band of TiO 2 . The enhanced surface adsorption characteristics and excellent charge transport separation were independent properties of the photocatalytic degradation process

  7. A Highly Stable and Magnetically Recyclable Nanocatalyst System: Mesoporous Silica Spheres Embedded with FeCo/Graphitic Shell Magnetic Nanoparticles and Pt Nanocatalysts.

    Science.gov (United States)

    Kim, Da Jeong; Li, Yan; Kim, Yun Jin; Hur, Nam Hwi; Seo, Won Seok

    2015-12-01

    We have developed a highly stable and magnetically recyclable nanocatalyst system for alkene hydrogenation. The materials are composed of mesoporous silica spheres (MSS) embedded with FeCo/graphitic shell (FeCo/GC) magnetic nanoparticles and Pt nanocatalysts (Pt-FeCo/GC@MSS). The Pt-FeCo/GC@MSS have superparamagnetism at room temperature and show type IV isotherm typical for mesoporous silica, thereby ensuring a large enough inner space (surface area of 235.3 m(2)  g(-1), pore volume of 0.165 cm(3)  g(-1), and pore diameter of 2.8 nm) to undergo catalytic reactions. We have shown that the Pt-FeCo/GC@MSS system readily converts cyclohexene into cyclohexane, which is the only product isolated and Pt-FeCo/GC@MSS can be seperated very quickly by an external magnetic field after the catalytic reaction is finished. We have demonstrated that the recycled Pt-FeCo/GC@MSS can be reused further for the same hydrogenation reaction at least four times without loss in the initial catalytic activity. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Nanostructured Mesoporous Silicas for Bone Tissue Regeneration

    Directory of Open Access Journals (Sweden)

    Isabel Izquierdo-Barba

    2008-01-01

    Full Text Available The research on the development of new biomaterials that promote bone tissue regeneration is receiving great interest by the biomedical scientific community. Recent advances in nanotechnology have allowed the design of materials with nanostructure similar to that of natural bone. These materials can promote new bone formation by inducing the formation of nanocrystalline apatites analogous to the mineral phase of natural bone onto their surfaces, i.e. they are bioactive. They also stimulate osteoblast proliferation and differentiation and, therefore, accelerate the healing processes. Silica-based ordered mesoporous materials are excellent candidates to be used as third generation bioceramics that enable the adsorption and local control release of biological active agents that promote bone regeneration. This local delivery capability together with the bioactive behavior of mesoporous silicas opens up promising expectations in the bioclinical field. In this review, the last advances in nanochemistry aimed at designing and tailoring the chemical and textural properties of mesoporous silicas for biomedical applications are described. The recent developed strategies to synthesize bioactive glasses with ordered mesopore arrangements are also summarized. Finally, a deep discussion about the influence of the textural parameters and organic modification of mesoporous silicas on molecules adsorption and controlled release is performed.

  9. Mesoporous TiO{sub 2} nanoparticles for highly sensitive solid-phase microextraction of organochlorine pesticides

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Shuqin; Xie, Lijun; Zheng, Juan; Jiang, Ruifeng; Zhu, Fang; Luan, Tiangang; Ouyang, Gangfeng, E-mail: cesoygf@mail.sysu.edu.cn

    2015-06-09

    Highlights: • Mesoporous TiO{sub 2} nanoparticles were synthesized and characterized. • A novel SPME fiber was fabricated with silicone sealant film and TiO{sub 2} powder. • The fiber exhibited excellent extraction performance to OCPs. • The fiber was used for analysis of OCPs in real water samples. - Abstract: Mesoporous TiO{sub 2} nanoparticles were synthesized with the hydrothermal method and characterized by powder X-ray diffraction (PXRD) and transmission electron microscope (TEM). Then a superior solid-phase microextraction (SPME) fiber was fabricated by sequentially coating the stainless steel fiber with silicone sealant film and mesoporous TiO{sub 2} powder. The developed fiber possessed a homogeneous surface and a long life-span up to 100 times at direct immersing (DI) extraction mode. Under the optimized conditions, the extraction efficiencies of the self-made 17 μm TiO{sub 2} fiber for six organochlorine pesticides (OCPs) were higher than those of the two commercial fibers (65 μm PDMS/DVB and 85 μm PA fibers) which were much thicker than the former. As for analytical performance, low detection limits (0.08–0.60 ng L{sup −1}) and wide linearity (5–5000 ng L{sup −1}) were achieved under the optimal conditions. The repeatabilities (n = 5) for single fiber were between 2.8 and 12.3%, while the reproducibilities (n = 3) of fiber-to-fiber were in the range of 3.7–15.7%. The proposed fiber was successfully applied to the sensitive analysis of OCPs in real water samples and four of the six analytes were detected from the rainwater and the lake water samples.

  10. The Effect of Mesoporous Carbon Nitride Modification by Titanium Oxide Nanoparticles on Photocatalytic Degradation of 1,3-Dinitrobenzene

    Directory of Open Access Journals (Sweden)

    Seyyed Ershad Moradi

    2015-11-01

    Full Text Available In the present work, well ordered, mesoporous carbon nitride (MCN sorbent with uniform mesoporous wall, high surface area and pore volume has been fabricated using the simple polymerization reaction between ethylene diamine and carbon tetrachloride in mesoporous silica media, and then modified by TiO2 nanoparticles (Ti-MCN. The structural order and textural properties of the nanoporous materials were studied by XRD, elemental analysis, and nitrogen adsorption–desorption experiments. Photodegradation experiments for 1,3-dinitrobenzene were conducted in batch mode, the Ti-MCN catalysts were found to be more active compared to the free TiO2 nanoparticles for 1,3-dinitrobenzene degradation.

  11. Facile preparation of magnetic mesoporous Fe_3O_4/C/Cu composites as high performance Fenton-like catalysts

    International Nuclear Information System (INIS)

    Li, Keyan; Zhao, Yongqin; Janik, Michael J.; Song, Chunshan; Guo, Xinwen

    2017-01-01

    Highlights: • Fe-Cu composites with different compositions were prepared by calcining tartrates. • Magnetic mesoporous Fe_3O_4/C/Cu was obtained by calcining tartrate under N_2. • Fe_3O_4/C/Cu exhibits excellent photo-Fenton catalytic activity and reusability. • The activity is due to the synergistic and photo-reduction effects of Fe and Cu. - Abstract: Fe-Cu composites with different compositions and morphologies were synthesized by a hydrothermal method combined with precursor thermal transformation. γ-Fe_2O_3/CuO and α-Fe_2O_3/CuO were obtained by calcining the Fe and Cu tartrates under air atmosphere at 350 °C and 500 °C, respectively, while Fe_3O_4/C/Cu was obtained by calcining the tartrate precursor under N_2 atmosphere at 500 °C. The Fe_3O_4/C/Cu composite possessed mesoporous structure and large surface area up to 133 m"2 g"−"1. The Fenton catalytic performance of Fe_3O_4/C/Cu composite was closely related to the Fe/Cu molar ratio, and only proper amounts of Fe and Cu exhibited a synergistic enhancement in Fenton catalytic activity. Cu inclusion reduced Fe"3"+ to Fe"2"+, which accelerated the Fe"3"+/Fe"2"+ cycles and favored H_2O_2 decomposition to produce more hydroxyl radicals for methylene blue (MB) oxidation. Due to the photo-reduction of Fe"3"+ and Cu"2"+, the Fenton catalytic performance was greatly improved when amending with visible light irradiation in the Fe_3O_4/C/Cu-H_2O_2 system, and MB (100 mg L"−"1) was nearly removed within 60 min. The Fe_3O_4/C/Cu composite showed good recyclability and could be conveniently separated by an applied magnetic field. Compared with conventional methods for mesoporous composite construction, the thermolysis method using mixed metal tartrates as precursors has the advantages of easy preparation and low cost. This strategy provides a facile, cheap and green method for the synthesis of mesoporous composites as excellent Fenton-like catalysts, without any additional reductants or organic

  12. Direct access to highly crystalline mesoporous nano TiO2 using sterically bulky organic acid templates

    Science.gov (United States)

    Bakre, Pratibha V.; Tilve, S. G.

    2018-05-01

    Sterically bulky monocarboxylic acid templates pivalic acid and phenoxyacetic acid are reported for the first time as organic templates in the sol-gel synthesis of TiO2. Mesoporous nanoparticulates of pure anatase phase and of well defined size were synthesized. The characterization of the materials prepared was done by various methods such as XRD, SEM, TEM, FTIR, UV-DRS, BET, etc. The prepared TiO2 samples were evaluated for the day light photodegradation of methylene blue by comparing with Degussa P25 and templates free synthesized TiO2 and were found to be more efficient.

  13. Mesoporous Bragg reflectors: block-copolymer self-assembly leads to building blocks with well defined continuous pores and high control over optical properties

    KAUST Repository

    Guldin, S.

    2011-08-19

    Mesoporous distributed Bragg re ectors (MDBRs) exhibit porosity on the sub-optical length scale. This makes them ideally suited as sensing platforms in biology and chemistry as well as for light management in optoelectronic devices. Here we present a new fast forward route for the fabrication of MDBRs which relies on the self-assembling properties of the block copolymer poly(isoprene-block -ethylene oxide) (PI-b -PEO) in combination with sol-gel chemistry. The interplay between structure directing organic host and co-assembled inorganic guest allows the ne tuning of refractive index in the outcome material. The refractive index dierence between the high and low porosity layer can be as high as 0.4, with the optical interfaces being well dened. Following a 30 min annealing protocol after each layer deposition enables the fast and reliable stacking of MDBRs which exhibit a continuous TiO2 network with large accessible pores and high optical quality.

  14. Synthesis of ultrathin mesoporous NiCo2O4 nanosheets on carbon fiber paper as integrated high-performance electrodes for supercapacitors

    Science.gov (United States)

    Deng, Fangze; Yu, Lin; Cheng, Gao; Lin, Ting; Sun, Ming; Ye, Fei; Li, Yongfeng

    2014-04-01

    Two-dimensional ultrathin mesoporous NiCo2O4 nanosheets on carbon fiber paper (CFP) are synthesized through a facile solvothermal method combined with a post thermal treatment. The well interconnected ultrathin NiCo2O4 nanosheets directly grown on the carbon nanofibers could allow for easy diffusion of the electrolyte, shorten the transport path of ion and electron and accommodate the strain during cycling. As a result, superior pseudocapacitive performance is achieved with large specific capacitance of 999 F g-1 at a high current density of 20 A g-1. The capacitance loss is 15.6% after 3000 cycles at a current density of 10 A g-1, displaying good cycle ability and high rate capability.

  15. Investigation of heterogeneous asymmetric dihydroxylation over OsO{sub 4}-(QN){sub 2}PHAL catalysts of functionalized bimodal mesoporous silica with ionic liquid

    Energy Technology Data Exchange (ETDEWEB)

    Qiu, Shenjie [College of Environmental and Energy Engineering, Beijing University of Technology, Beijing 100124 (China); Sun, Jihong, E-mail: jhsun@bjut.edu.cn [College of Environmental and Energy Engineering, Beijing University of Technology, Beijing 100124 (China); Li, Yuzhen; Gao, Lin [College of Environmental and Energy Engineering, Beijing University of Technology, Beijing 100124 (China)

    2011-08-15

    Highlights: {yields} Functionalized bimodal mesoporous silica with MTMSPIm{sup +}Cl{sup -}. {yields} Mesoporous catalyst immobilized with OsO{sub 4}-(QN){sub 2}PHAL. {yields} Catalysts for asymmetric dihydroxylation reaction with high yield and enatioselectivity. {yields} Recyclable catalysts. -- Abstract: A novel synthesis of the functionalized bimodal mesoporous silica with ionic liquid (FBMMs) was performed. After grafting 1-methyl-3-(trimethoxysilyl)propylimidazolium chloride onto the surface of bimodal mesoporous silicas, 1,4-bis(9-O-quininyl)phthalazine ((QN){sub 2}-PHAL) and K{sub 2}Os(OH){sub 4}.2H{sub 2}O were immobilized onto the modified FBMMs by adsorption or ionic exchange methods, and then, the asymmetric dihydroxylation reaction was carried out by using solid catalysts. Techniques such as X-ray diffraction, Fourier Transform Infrared spectroscopy, N{sub 2} adsorption and desorption were employed to characterize their structure and properties. The results showed that the mesoporous ordering degree of bimodal mesoporous silica decreased after functionalization and immobilization of OsO{sub 4}-(QN){sub 2}PHAL. Being very effective in asymmetric dihydroxylation with high yield and enantioselectivity, the prepared heterogeneous solid catalyst could be recycled for five times with little loss of enantioselectivity, with comparison of those results obtained in homophase system. Moreover, the effect of Osmium catalyst on asymmetric dihydroxylation was investigated.

  16. Tailored Design of Bicontinuous Gyroid Mesoporous Carbon and Nitrogen-Doped Carbon from Poly(ethylene oxide-b-caprolactone) Diblock Copolymers.

    Science.gov (United States)

    Chu, Wei-Cheng; Bastakoti, Bishnu Prasad; Kaneti, Yusuf Valentino; Li, Jheng-Guang; Alamri, Hatem R; Alothman, Zeid A; Yamauchi, Yusuke; Kuo, Shiao-Wei

    2017-10-04

    Highly ordered mesoporous resol-type phenolic resin and the corresponding mesoporous carbon materials were synthesized by using poly(ethylene oxide-b-caprolactone) (PEO-b-PCL) diblock copolymer as a soft template. The self-assembled mesoporous phenolic resin was found to form only in a specific resol concentration range of 40-70 wt % due to an intriguing balance of hydrogen-bonding interactions in the resol/PEO-b-PCL mixtures. Furthermore, morphological transitions of the mesostructures from disordered to gyroid to cylindrical and finally to disordered micelle structure were observed with increasing resol concentration. By calcination under nitrogen atmosphere at 800 °C, the bicontinuous mesostructured gyroid phenolic resin could be converted to mesoporous carbon with large pore size without collapse of the original mesostructure. Furthermore, post-treatment of the mesoporous gyroid phenolic resin with melamine gave rise to N-doped mesoporous carbon with unique electronic properties for realizing high CO 2 adsorption capacity (6.72 mmol g -1 at 0 °C). © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Plutonium sorption to nanocast mesoporous carbon

    Energy Technology Data Exchange (ETDEWEB)

    Parsons-Moss, Tashi; Wang, Deborah; Jones, Stephen; Olive, Daniel; Nitsche, Heino [California Univ., Berkeley, CA (United States). Dept. of Chemistry; Lawrence Berkeley National Laboratory, Berkeley, CA (United States). Nuclear Science Div.; Tueysuez, Harun [Lawrence Berkeley National Laboratory, Berkeley, CA (United States). Nuclear Science Div.; Max-Planck-Institut fuer Kohlenforschung, Muelheim an der Ruhr (Germany)

    2014-09-01

    Nanocast ordered mesoporous carbons are attractive as sorbents because of their extremely high surface areas and large pore volumes. This paper compares Pu uptake, added as Pu(VI), to both untreated and chemically oxidized CMK-(carbon molecular sieves from KAIST) type mesoporous carbon with that to a commercial amorphous activated carbon. The CMK was synthesized via nanocasting by using cubic ordered mesoporous silica KIT-6 as a hard template, and characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), and nitrogen adsorption. A portion of the CMK was oxidized by treatment with nitric acid, and will be called OX CMK. The three carbon powders have similar particle morphology, and high BET surface areas. The activated carbon is disordered, while the CMK materials show large domains of ordered cubic mesostructure. The CMK material seems to have more oxygen-containing functional groups than the activated carbon, and the oxidation of the CMK increased the density of these groups, especially - COOH, thus lowering the point of zero charge (PZC) of the material. Batch studies of all 3 materials with plutonium solutions, in a 0.1 M NaClO{sub 4} matrix were performed to investigate pH dependence, sorption kinetics, Pu uptake capacities, competition with ethylenediaminetetraacetic acid (EDTA) in solution, and Pu desorption. Both CMK materials demonstrated high Pu sorption from solutions of pH 3 or greater, and the oxidized CMK also showed high sorption from pH 2 solutions. The activated carbon bound less Pu, and at a much slower rate than CMK. All other batch experiments were carried out in pH 4 solutions. The Pu uptake from low-concentration solutions was faster for the oxidized CMK than for untreated CMK, but in more concentrated samples (∝ 250 μM Pu), the Pu uptake kinetics and apparent capacity were the same for oxidized and untreated CMK. The 23-h Pu uptake capacity of the CMK

  18. Design and synthesis of hierarchical mesoporous WO3-MnO2 composite nanostructures on carbon cloth for high-performance supercapacitors

    Science.gov (United States)

    Shinde, Pragati A.; Lokhande, Vaibhav C.; Patil, Amar M.; Ji, Taeksoo; Lokhande, Chandrakant D.

    2017-12-01

    To enhance the energy density and power performance of supercapacitors, the rational design and synthesis of active electrode materials with hierarchical mesoporous structure is highly desired. In the present work, fabrication of high-performance hierarchical mesoporous WO3-MnO2 composite nanostructures on carbon cloth substrate via a facile hydrothermal method is reported. By varying the content of MnO2 in the composite, different WO3-MnO2 composite thin films are obtained. The formation of composite is confirmed by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analyses. The Brunauer-Emmett-Teller (BET) analysis reveals maximum specific surface area of 153 m2 g-1. The optimized WO3-MnO2 composite electrode demonstrates remarkable electrochemical performance with high specific capacitance of 657 F g-1 at a scan rate of 5 mV s-1 and superior longterm cycling stability (92% capacity retention over 2000 CV cycles). Furthermore, symmetric flexible solid-state supercapacitor based on WO3-MnO2 electrodes has been fabricated. The device exhibits good electrochemical performance with maximum specific capacitance of 78 F g-1 at a scan rate of 5 mV s-1 and specific energy of 10.8 Wh kg-1 at a specific power of 0.65 kW kg-1. The improved electrochemical performance could be ascribed to the unique combination of multivalence WO3 and MnO2 nanostructures and synergistic effect between them

  19. Photocatalytic performance of highly amorphous titania–silica aerogels with mesopores: The adverse effect of the in situ adsorption of some organic substrates during photodegradation

    Energy Technology Data Exchange (ETDEWEB)

    Lázár, István [Department of Inorganic and Analytical Chemistry, University of Debrecen, Egyetem tér 1 H-4032 (Hungary); Kalmár, József, E-mail: kalmar.jozsef@science.unideb.hu [MTA-DE Homogeneous Catalysis and Reaction Mechanisms Research Group, Egyetem tér 1 H-4032 (Hungary); Peter, Anca [Department of Chemistry and Biology, Technical University of Cluj Napoca, North University Center of Baia Mare, Baia Mare, Victoriei 76, 430122 (Romania); Szilágyi, Anett; Győri, Enikő; Ditrói, Tamás; Fábián, István [Department of Inorganic and Analytical Chemistry, University of Debrecen, Egyetem tér 1 H-4032 (Hungary)

    2015-11-30

    Graphical abstract: - Highlights: • Details on the preparation of titania–silica aerogels with no crystalline anatase phase. • Investigation of the structure and the photocatalytic activity of highly amorphous titania–silica aerogels with mesopores. • The fast adsorption of methylene blue and salicylic acid reduces the rates of their photocatalytic degradations. • An elaborate kinetic model which incorporates both adsorption and photocatalysis. - Abstract: Titania–silica composite aerogels with 16–29% Ti-content by the mass were synthesized by the sol–gel method from different Ti-precursors, and calcined at 500 °C. These aerogels are highly amorphous as no crystalline TiO{sub 2} phase can be detected in them by X-ray diffraction methods, and show the dominating presence of either mesopores or macropores. The incorporation of Ti into the silica structure is shown by the appearance of characteristic IR transitions of Si−O−Ti vibrations. The characteristic band-gap energies of the different aerogels are estimated to be between 3.6 and 3.9 eV from UV reflection spectra. Band-gap energy decreases with decreasing pore-size. When suspended in solution, even these highly amorphous aerogels accelerate the photodegradation of salicylic acid and methylene blue compared to simple photolysis. Kinetic experiments were conducted under illumination, and also in the dark to study the adsorption of the substrates onto the suspended aerogels. We assume that the fast in situ adsorption of the organic substrates mask the suspended aerogel particles from UV photons, which reduces the rate of photocatalysis. We managed to mathematically separate the parallel processes of photocatalysis and adsorption, and develop a simple kinetic model to describe the reaction system.

  20. Preparation and characterization of mesoporous TiO{sub 2}-sphere-supported Au-nanoparticle catalysts with high activity for CO oxidation at ambient temperature

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Lili; Huang, Shouying; Zhu, Baolin; Zhang, Shoumin; Huang, Weiping, E-mail: hwp914@nankai.edu.cn [Nankai University, College of Chemistry, The Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education), and Tianjin Key Lab of Metal and Molecule-based Material Chemistry (China)

    2016-11-15

    Mesoporous TiO{sub 2}-sphere-supported Au-nanoparticles (Au/m-TiO{sub 2}-spheres) catalysts have been synthesized by a simple method using tetrabutyl titanate as TiO{sub 2} precursor and characterized with XRD, BET, ICP, SEM, TEM, UV-Vis DRS, XPS, as well as FT-IR. The samples with the size in the range of 200–400 nm were almost perfectly spherical. The average diameter of pores was about 3.6 nm, and the mesopore size distribution was in the range of 2–6 nm with a narrow distribution. When the catalyst was calcined at 300 °C, the Au NPs with the size ca. 5 nm were highly dispersed on the surfaces of m-TiO{sub 2} spheres and partially embedded in the supports. Remarkably, the specific surface area of the Au/m-TiO{sub 2}-spheres was as high as 117 m{sup 2} g{sup −1}. The CO-adsorbed catalyst showed an apparent IR adsorption peak at 1714 cm{sup −1} that matched with bridging model CO. It means the catalysts should be of high catalytic activity for the CO oxidation due to they could adsorb and activate CO commendably. When Au-content was 0.48 wt.%, the Au/m-TiO{sub 2}-spheres could convert CO completely into CO{sub 2} at ambient temperature.

  1. High performance of mesoporous γ-Fe2O3 nanoparticle/Ketjen Black composite as anode material for lithium ion batteries

    International Nuclear Information System (INIS)

    Dong, Hui; Xu, Yunlong; Ji, Mandi; Zhang, Huang; Zhao, Zhen; Zhao, Chongjun

    2015-01-01

    Highlights: • A mesoporous γ-Fe 2 O 3 /KB composite was synthesized via solvothermal method. • KB was used as a carbon template to improve electrochemical performance of γ-Fe 2 O 3 . • 3D network structure can relieve volume change and improve the ionic transport. • The composite exhibited an ultrahigh capacity and high rate performance. - Abstract: A type of γ-Fe 2 O 3 nanoparticle/Ketjen Black (KB) composite material is synthesized by a solvothermal method combined with precursor thermal transformation. The structure and morphology are characterized by XRD, raman spectra, TG, nitrogen sorption, SEM, TEM and EDS. The results show that the composite has a uniform nanoporous network and well-dispersed γ-Fe 2 O 3 particles with a size of ca. 5 nm are embedded in the mesopores of KB. The γ-Fe 2 O 3 /KB exhibits superior eletrochemical performances to the bare γ-Fe 2 O 3 , especially at high current rate. The discharge capacity of the composite is 1100 mAh·g −1 at the first cycle and remains 988.8 mAh·g −1 after 100 cycles at 0.2 C. Moreover, it also maintains a high discharge capacity of 697.8 mAh·g −1 at 2 C and 410.1 mAh·g −1 at 5 C after 100 cycles, respectively. Such improved electrochemical performances could be attributed to the superior conductivity and favorable structure of KB, which contributes to the improvement in electronic conductivity and structure stability of γ-Fe 2 O 3 during the lithium ion insertion/desertion process

  2. Isomeric periodic mesoporous organosilicas with controllable properties

    NARCIS (Netherlands)

    Vercaemst, C.; Ide, I.; Friedrich, H.; de Jong, K.P.; Verpoort, F.; van der Voort, P.

    2009-01-01

    The synthesis procedure for isomeric periodic mesoporous organosilicas with E-configured ethenylene bridges was investigated using the homemade pure E-isomer of 1,2-bis(triethoxysilyl)ethene. The pH, aging temperature and the presence of cosolvents played a key role in obtaining well-ordered

  3. Generation of intense high-order vortex harmonics.

    Science.gov (United States)

    Zhang, Xiaomei; Shen, Baifei; Shi, Yin; Wang, Xiaofeng; Zhang, Lingang; Wang, Wenpeng; Xu, Jiancai; Yi, Longqiong; Xu, Zhizhan

    2015-05-01

    This Letter presents for the first time a scheme to generate intense high-order optical vortices that carry orbital angular momentum in the extreme ultraviolet region based on relativistic harmonics from the surface of a solid target. In the three-dimensional particle-in-cell simulation, the high-order harmonics of the high-order vortex mode is generated in both reflected and transmitted light beams when a linearly polarized Laguerre-Gaussian laser pulse impinges on a solid foil. The azimuthal mode of the harmonics scales with its order. The intensity of the high-order vortex harmonics is close to the relativistic region, with the pulse duration down to attosecond scale. The obtained intense vortex beam possesses the combined properties of fine transversal structure due to the high-order mode and the fine longitudinal structure due to the short wavelength of the high-order harmonics. In addition to the application in high-resolution detection in both spatial and temporal scales, it also presents new opportunities in the intense vortex required fields, such as the inner shell ionization process and high energy twisted photons generation by Thomson scattering of such an intense vortex beam off relativistic electrons.

  4. Uric acid-derived Fe3C-containing mesoporous Fe/N/C composite with high activity for oxygen reduction reaction in alkaline medium

    Science.gov (United States)

    Ma, Jun; Xiao, Dejian; Chen, Chang Li; Luo, Qiaomei; Yu, Yue; Zhou, Junhao; Guo, Changding; Li, Kai; Ma, Jie; Zheng, Lirong; Zuo, Xia

    2018-02-01

    In this work, a category of Fe3C-containing Fe/N/C mesoporous material has been fabricated by carbonizing the mixture of uric acid, Iron (Ⅲ) chloride anhydrous and carbon support (XC-72) under different pyrolysis temperature. Of all these samples, pyrolysis temperature (800 °C) becomes the most crucial factor in forming Fe3C active sites which synergizes with high content of graphitic N to catalyze oxygen reduction reaction (ORR). X-ray absorption fine structure spectroscopy (XAFS) is used to exhibit that the space structure around Fe atoms in the catalyst. This kind of catalyst possesses comparable ORR properties with commercial 20% Pt/C (onset potential is 0 V vs. Ag/AgCl in 0.1 M KOH), the average transfer electron number is 3.84 reflecting the 4-electron process. Moreover, superior stability and methanol tolerance deserve to be mentioned.

  5. Thermal decomposition pathway of undoped and doped zinc layered gallate nanohybrid with Fe 3+, Co 2+ and Ni 2+ to produce mesoporous and high pore volume carbon material

    Science.gov (United States)

    Ghotbi, Mohammad Yeganeh; bin Hussein, Mohd Zobir; Yahaya, Asmah Hj; Abd Rahman, Mohd Zaki

    2009-12-01

    A series of brucite-like materials, undoped and doped zinc layered hydroxide nitrate with 2% (molar) Fe 3+, Co 2+ and Ni 2+ were synthesized. Organic-inorganic nanohybrid material with gallate anion as a guest, and zinc hydroxide nitrate, as an inorganic layered host was prepared by the ion-exchange method. The nanohybrid materials were heat-treated at various temperatures, 400-700 °C. X-ray diffraction, thermal analysis and also Fourier transform infrared results showed that incorporation of the doping agents within the zinc layered hydroxide salt layers has enhanced the heat-resistivity of the nanohybrid materials in the thermal decomposition pathway. Porous carbon materials can be obtained from the heat-treating the nanohybrids at 600 and 700 °C. Calcination of the nanohybrids at 700 °C under nitrogen atmosphere produces mesoporous and high pore volume carbon materials.

  6. Microstructure and Magnetic Properties of Highly Ordered SBA-15 Nanocomposites Modified with Fe2O3 and Co3O4 Nanoparticles

    Directory of Open Access Journals (Sweden)

    P. F. Wang

    2012-01-01

    Full Text Available Owing to the unique order mesopores, mesoporous SBA-15 could be used as the carrier of the magnetic nanoparticles. The magnetic nanoparticles in the frame and the mesopores lead to the exchange-coupling interaction or other interactions, which could improve the magnetic properties of SBA-15 nanocomposites. Mesoporous Fe/SBA-15 had been prepared via in situ anchoring Fe2O3 into the frame and the micropores of SBA-15 using the sol-gel and hydrothermal processes. Co3O4 nanoparticles had been impregnated into the mesopores of Fe/SBA-15 to form mesoporous Fe/SBA-15-Co3O4 nanocomposites. XRD, HRTEM, VSM, and N2 physisorption isotherms were used to characterize the mesostructure and magnetic properties of the SBA-15 nanocomposites, and all results indicated that the Fe2O3 nanoparticles presented into the frame and micropores, while the Co3O4 nanoparticles existed inside the mesopores of Fe/SBA-15. Furthermore, the magnetic properties of SBA-15 could be conveniently adjusted by the Fe2O3 and Co3O4 magnetic nanoparticles. Fe/SBA-15 exhibited ferromagnetic properties, while the impregnation of Co3O4 nanoparticles greatly improved the coercivity with a value of 1424.6 Oe, which was much higher than that of Fe/SBA-15.

  7. Contribution of mesopores in MgO-templated mesoporous carbons to capacitance in non-aqueous electrolytes

    Science.gov (United States)

    Kado, Yuya; Soneda, Yasushi; Yoshizawa, Noriko

    2015-02-01

    MgO-templated mesoporous carbons were fabricated by annealing trimagnesium dicitrate nonahydrate at various temperatures from 700 to 1000 °C with subsequent acid leaching of MgO. The obtained carbons contained a large amount of mesopores. Performances of electric double-layer capacitors using these carbons were examined for propylene carbonate electrolyte containing 1 M tetraethylammonium tetrafluoroborate. The mesoporous carbons synthesized at higher temperatures showed better rate capabilities. AC impedance measurements indicated that high-temperature annealing of the carbon precursors and the presence of mesopores were important for high rate performance. In addition, the contribution of mesopores to capacitance was more significant at higher current densities of 30 A g-1.

  8. Efficient Unsteady Flow Visualization with High-Order Access Dependencies

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Jiang; Guo, Hanqi; Yuan, Xiaoru

    2016-04-19

    We present a novel high-order access dependencies based model for efficient pathline computation in unsteady flow visualization. By taking longer access sequences into account to model more sophisticated data access patterns in particle tracing, our method greatly improves the accuracy and reliability in data access prediction. In our work, high-order access dependencies are calculated by tracing uniformly-seeded pathlines in both forward and backward directions in a preprocessing stage. The effectiveness of our proposed approach is demonstrated through a parallel particle tracing framework with high-order data prefetching. Results show that our method achieves higher data locality and hence improves the efficiency of pathline computation.

  9. Mesoporous C/CrN and C/VN Nanocomposites Obtained by One-Pot Soft-Templating Process

    Directory of Open Access Journals (Sweden)

    Julien Kiener

    2016-07-01

    Full Text Available Nanocomposites of ordered mesoporous carbon associated with chromium nitride (CrN or vanadium nitride (VN nanoparticles were obtained by a simple one-pot synthesis based on the solvent evaporation induced self-assembly (EISA process using Pluronic triblock surfactant as soft-template and a phenol-based resin (resol as carbon precursor. These nanocomposites were characterized by X-ray diffraction, nitrogen physisorption and Transmission Electron Microscopy (TEM techniques. Electron tomography (or 3D-TEM technique was particularly useful for providing direct insight on the internal architecture of C/CrN nanocomposite. Nanocomposites showed a very well organized hexagonal mesoporous carbon structure and a relatively high concentration of nanoparticles well distributed in the porous network. The chromium and vanadium nitrides/mesoporous carbon nanocomposites could have many potential applications in catalysis, Li-ion batteries, and supercapacitors.

  10. Template method synthesis of mesoporous carbon spheres and its applications as supercapacitors

    Science.gov (United States)

    Wilgosz, Karolina; Chen, Xuecheng; Kierzek, Krzysztof; Machnikowski, Jacek; Kalenczuk, Ryszard J.; Mijowska, Ewa

    2012-05-01

    Mesoporous carbon spheres (MCS) have been fabricated from structured mesoporous silica sphere using chemical vapor deposition (CVD) with ethylene as a carbon feedstock. The mesoporous carbon spheres have a high specific surface area of 666.8 m2/g and good electrochemical properties. The mechanism of formation mesoporous carbon spheres (carbon spheres) is investigated. The important thing is a surfactant hexadecyl trimethyl ammonium bromide (CTAB), which accelerates the process of carbon deposition. An additional advantage of this surfactant is an increase the yield of product. These mesoporous carbon spheres, which have good electrochemical properties is suitable for supercapacitors.

  11. [Study on absorbing volatile oil with mesoporous carbon].

    Science.gov (United States)

    Yan, Hong-mei; Jia, Xiao-bin; Zhang, Zhen-hai; Sun, E; Yang Nan

    2014-11-01

    Clove oil and turmeric oil were absorbed by mesoporous carbon. The absorption ratio of mesoporous carbon to volatile oil was optimized with the eugenol yield and curcumol yield as criteria Curing powder was characterized by scanning electron microscopy (SEM) and differential scanning calorietry (DSC). The effects of mesoporous carbon on dissolution in vitro and thermal stability of active components were studied. They reached high adsorption rate when the absorption ratio of mesoporous carbon to volatile oil was 1:1. When volatile oil was absorbed, dissolution rate of active components had a little improvement and their thermal stability improved after volatile oil was absorbed by the loss rate decreasing more than 50%. Absorbing herbal volatile oil with mesoporous carbon deserves further studying.

  12. Intra-cavity generation of high order LGpl modes

    CSIR Research Space (South Africa)

    Ngcobo, S

    2012-08-01

    Full Text Available with the location of the Laguerre polynomial zeros. The Diffractive optical element is used to shape the TEM00 Gaussian beam and force the laser to operate on a higher order LGpl Laguerre-Gaussian modes or high order superposition of Laguerre-Gaussian modes...

  13. Soft-Templating Synthesis of Mesoporous Silica-Based Materials for Environmental Applications

    Science.gov (United States)

    Gunathilake, Chamila Asanka

    Dissertation research is mainly focus on: 1) the development of mesoporous silica materials with organic pendant and bridging groups (isocyanurate, amidoxime, benzene) and incorporated metal (aluminum, zirconium, calcium, and magnesium) species for high temperature carbon dioxide (CO2) sorption, 2) phosphorous-hydroxy functionalized mesoporous silica materials for water treatment, and 3) amidoxime-modified ordered mesoporous silica materials for uranium sorption under seawater conditions. The goal is to design composite materials for environmental applications with desired porosity, surface area, and functionality by selecting proper metal oxide precursors, organosilanes, tetraethylorthosilicate, (TEOS), and block copolymer templates and by adjusting synthesis conditions. The first part of dissertation presents experimental studies on the merge of aluminum, zirconium, calcium, and magnesium oxides with mesoporous silica materials containing organic pendant (amidoxime) and bridging groups (isocyanurate, benzene) to obtain composite sorbents for CO2 sorption at ambient (0-25 °C) and elevated (60-120 °C) temperatures. These studies indicate that the aforementioned composite sorbents are fairly good for CO2 capture at 25 °C via physisorption mechanism and show a remarkably high affinity toward CO2 chemisorption at 60-120 °C. The second part of dissertation is devoted to silica-based materials with organic functionalities for removal of heavy metal ions such as lead from contaminated water and for recovery of metal ions such as uranium from seawater. First, ordered mesoporous organosilica (OMO) materials with diethylphosphatoethyl and hydroxyphosphatoethyl surface groups were examined for Pb2+ adsorption and showed unprecedented adsorption capacities up to 272 mg/g and 202 mg/g, respectively However, the amidoxime-modified OMO materials were explored for uranium extraction under seawater conditions and showed remarkable capacities reaching 57 mg of uranium per gram

  14. Catalytic hydrodeoxygenation of 2-methoxy phenol and dibenzofuran over Pt/mesoporous zeolites

    International Nuclear Information System (INIS)

    Lee, Hyung Won; Jun, Bo Ram; Kim, Hannah; Kim, Do Heui; Jeon, Jong-Ki; Park, Sung Hoon; Ko, Chang Hyun; Kim, Tae-Wan; Park, Young-Kwon

    2015-01-01

    The hydrodeoxygenation of 2-methoxy phenol and dibenzofuran, which are representative model compounds of bio-oil, was performed using two different Pt/mesoporous zeolite catalysts, Pt/mesoporous Y and Pt/mesoporous MFI. The reforming of 2-methoxy phenol and dibenzofuran via catalytic hydrodeoxygenation was investigated using a batch reactor at 40 bar and 250 °C. The characteristics of the catalysts were analyzed by N 2 adsorption-desorption, X-ray diffraction, and NH 3 temperature programmed desorption. Pt/mesoporous zeolite catalysts containing both strong acid sites and mesopores showed the higher conversion of 2-methoxy phenol than Pt/SiO 2 and Pt/Si-MCM-48 with no acid sites, Pt/γ-Al 2 O 3 , and a mixture of mesoporous Y and Pt/SiO 2 , indicating the importance of both Pt and strong acid sites for high catalytic activity. Among the two Pt/mesoporous zeolite catalysts tested, the conversion of 2-methoxy phenol to cyclohexane over Pt/mesoporous Y was much higher than that over the Pt/mesoporous MFI. This was attributed to the better textural properties, such as surface area, pore volume and micropore size, compared to those of Pt/mesoporous MFI. The catalytic conversions of dibenzofuran obtained using two Pt/mesoporous zeolite catalysts were similar and the main products were 1,1′-bicyclohexyl, cyclopentylmethyl-cyclohexane and cyclohexane. In addition, the reaction mechanisms of 2-methoxy phenol and dibenzofuran over Pt/mesoporous zeolite were suggested. - Highlights: • HDO of 2-methoxy phenol and dibenzofuran was performed over Pt/mesoporous zeolites. • Pt/mesoporous zeolites have mesopores and strong acid sites. • Main product of HDO of 2-methoxy phenol was cyclohexane. • Main products of HDO of dibenzofuran were bicyclohexyl (BCH), i-BCH, and cyclohexane

  15. A high order solver for the unbounded Poisson equation

    DEFF Research Database (Denmark)

    Hejlesen, Mads Mølholm; Rasmussen, Johannes Tophøj; Chatelain, Philippe

    In mesh-free particle methods a high order solution to the unbounded Poisson equation is usually achieved by constructing regularised integration kernels for the Biot-Savart law. Here the singular, point particles are regularised using smoothed particles to obtain an accurate solution with an order...... of convergence consistent with the moments conserved by the applied smoothing function. In the hybrid particle-mesh method of Hockney and Eastwood (HE) the particles are interpolated onto a regular mesh where the unbounded Poisson equation is solved by a discrete non-cyclic convolution of the mesh values...... and the integration kernel. In this work we show an implementation of high order regularised integration kernels in the HE algorithm for the unbounded Poisson equation to formally achieve an arbitrary high order convergence. We further present a quantitative study of the convergence rate to give further insight...

  16. A general soft-enveloping strategy in the templating synthesis of mesoporous metal nanostructures.

    Science.gov (United States)

    Fang, Jixiang; Zhang, Lingling; Li, Jiang; Lu, Lu; Ma, Chuansheng; Cheng, Shaodong; Li, Zhiyuan; Xiong, Qihua; You, Hongjun

    2018-02-06

    Metal species have a relatively high mobility inside mesoporous silica; thus, it is difficult to introduce the metal precursors into silica mesopores and suppress the migration of metal species during a reduction process. Therefore, until now, the controlled growth of metal nanocrystals in a confined space, i.e., mesoporous channels, has been very challenging. Here, by using a soft-enveloping reaction at the interfaces of the solid, liquid, and solution phases, we successfully control the growth of metallic nanocrystals inside a mesoporous silica template. Diverse monodispersed nanostructures with well-defined sizes and shapes, including Ag nanowires, 3D mesoporous Au, AuAg alloys, Pt networks, and Au nanoparticle superlattices are successfully obtained. The 3D mesoporous AuAg networks exhibit enhanced catalytic activities in an electrochemical methanol oxidation reaction. The current soft-enveloping synthetic strategy offers a robust approach to synthesize diverse mesoporous metal nanostructures that can be utilized in catalysis, optics, and biomedicine applications.

  17. Synthesis of Ordered Mesoporous Carbon Loaded Fe, Co, Ni Nanocrystals by the Soft Templating Route and Their Characterization%有序介孔碳负载Fe、Co、Ni纳米晶的软模板合成及其表征

    Institute of Scientific and Technical Information of China (English)

    李健生; 顾娟; 凌晓凤; 孙秀云; 沈锦优; 韩卫清; 王连军

    2011-01-01

    报道了在有序介孔碳基体中一步合成负载Fe、Co、Ni纳米晶的方法.以间二苯酚和甲醛为碳源,F127为模板剂,Fe、Co、Ni的硝酸盐为前驱体,通过软模板组装路线在酸性条件下合成了负载型有序介孔碳复合材料.采用X射线衍射(XRD)、透射电镜(TEM)和氮气吸附等手段对所合成材料进行了表征.结果表明:合成的材料具有类似于SBA-15的有序介孔结构,有序介孔碳负载Fe、Co、Ni纳米晶复合材料的比表面积分别为586、626和698m2·g-1.XRD和TEM表征结果证实了金属物种以高分散纳米晶的形式分布在介孔碳基体中.%We report a one-step method for the synthesis of M(Fe, Co, Ni) nanocrystals supported by ordered mesoporous carbon (OMC) materials. M/OMC composites were obtained by the soft templating route under acidic conditions using resorcinol and formaldehyde as carbon precursors, tdblock copolymer Pluronic F127 as a template and Fe, Co, Ni nitrates as metal precursors. The as-synthesized materials were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and N2 adsorption.Characterization revealed that the as-synthesized materials possessed an ordered hexagonal mesoporous structure similar to SBA-15. The specific surface areas of the Fe/OMC, Co/OMC, and Ni/OMC composites were found to be 586, 626, and 698 m2· g-1, respectively. The fact that the metal species were present as highly dispersed nanocrystals in the OMC matrix was confirmed by XRD and high-resolution TEM.

  18. Analysis and Design of High-Order Parallel Resonant Converters

    Science.gov (United States)

    Batarseh, Issa Eid

    1990-01-01

    In this thesis, a special state variable transformation technique has been derived for the analysis of high order dc-to-dc resonant converters. Converters comprised of high order resonant tanks have the advantage of utilizing the parasitic elements by making them part of the resonant tank. A new set of state variables is defined in order to make use of two-dimensional state-plane diagrams in the analysis of high order converters. Such a method has been successfully used for the analysis of the conventional Parallel Resonant Converters (PRC). Consequently, two -dimensional state-plane diagrams are used to analyze the steady state response for third and fourth order PRC's when these converters are operated in the continuous conduction mode. Based on this analysis, a set of control characteristic curves for the LCC-, LLC- and LLCC-type PRC are presented from which various converter design parameters are obtained. Various design curves for component value selections and device ratings are given. This analysis of high order resonant converters shows that the addition of the reactive components to the resonant tank results in converters with better performance characteristics when compared with the conventional second order PRC. Complete design procedure along with design examples for 2nd, 3rd and 4th order converters are presented. Practical power supply units, normally used for computer applications, were built and tested by using the LCC-, LLC- and LLCC-type commutation schemes. In addition, computer simulation results are presented for these converters in order to verify the theoretical results.

  19. Efficiency of High Order Spectral Element Methods on Petascale Architectures

    KAUST Repository

    Hutchinson, Maxwell; Heinecke, Alexander; Pabst, Hans; Henry, Greg; Parsani, Matteo; Keyes, David E.

    2016-01-01

    High order methods for the solution of PDEs expose a tradeoff between computational cost and accuracy on a per degree of freedom basis. In many cases, the cost increases due to higher arithmetic intensity while affecting data movement minimally. As architectures tend towards wider vector instructions and expect higher arithmetic intensities, the best order for a particular simulation may change. This study highlights preferred orders by identifying the high order efficiency frontier of the spectral element method implemented in Nek5000 and NekBox: the set of orders and meshes that minimize computational cost at fixed accuracy. First, we extract Nek’s order-dependent computational kernels and demonstrate exceptional hardware utilization by hardware-aware implementations. Then, we perform productionscale calculations of the nonlinear single mode Rayleigh-Taylor instability on BlueGene/Q and Cray XC40-based supercomputers to highlight the influence of the architecture. Accuracy is defined with respect to physical observables, and computational costs are measured by the corehour charge of the entire application. The total number of grid points needed to achieve a given accuracy is reduced by increasing the polynomial order. On the XC40 and BlueGene/Q, polynomial orders as high as 31 and 15 come at no marginal cost per timestep, respectively. Taken together, these observations lead to a strong preference for high order discretizations that use fewer degrees of freedom. From a performance point of view, we demonstrate up to 60% full application bandwidth utilization at scale and achieve ≈1PFlop/s of compute performance in Nek’s most flop-intense methods.

  20. Efficiency of High Order Spectral Element Methods on Petascale Architectures

    KAUST Repository

    Hutchinson, Maxwell

    2016-06-14

    High order methods for the solution of PDEs expose a tradeoff between computational cost and accuracy on a per degree of freedom basis. In many cases, the cost increases due to higher arithmetic intensity while affecting data movement minimally. As architectures tend towards wider vector instructions and expect higher arithmetic intensities, the best order for a particular simulation may change. This study highlights preferred orders by identifying the high order efficiency frontier of the spectral element method implemented in Nek5000 and NekBox: the set of orders and meshes that minimize computational cost at fixed accuracy. First, we extract Nek’s order-dependent computational kernels and demonstrate exceptional hardware utilization by hardware-aware implementations. Then, we perform productionscale calculations of the nonlinear single mode Rayleigh-Taylor instability on BlueGene/Q and Cray XC40-based supercomputers to highlight the influence of the architecture. Accuracy is defined with respect to physical observables, and computational costs are measured by the corehour charge of the entire application. The total number of grid points needed to achieve a given accuracy is reduced by increasing the polynomial order. On the XC40 and BlueGene/Q, polynomial orders as high as 31 and 15 come at no marginal cost per timestep, respectively. Taken together, these observations lead to a strong preference for high order discretizations that use fewer degrees of freedom. From a performance point of view, we demonstrate up to 60% full application bandwidth utilization at scale and achieve ≈1PFlop/s of compute performance in Nek’s most flop-intense methods.

  1. Enhanced high-order harmonic generation from Argon-clusters

    NARCIS (Netherlands)

    Tao, Yin; Hagmeijer, Rob; Bastiaens, Hubertus M.J.; Goh, S.J.; van der Slot, P.J.M.; Biedron, S.; Milton, S.; Boller, Klaus J.

    2017-01-01

    High-order harmonic generation (HHG) in clusters is of high promise because clusters appear to offer an increased optical nonlinearity. We experimentally investigate HHG from Argon clusters in a supersonic gas jet that can generate monomer-cluster mixtures with varying atomic number density and

  2. Highly flexible self-standing film electrode composed of mesoporous rutile TiO2/C nanofibers for lithium-ion batteries

    International Nuclear Information System (INIS)

    Zhao Bote; Cai Rui; Jiang Simin; Sha Yujing; Shao Zongping

    2012-01-01

    There is increasing interest in flexible, safe, high-power thin-film lithium-ion batteries which can be applied to various modern devices. Although TiO 2 in rutile phase is highly attractive as an anode material of lithium-ion batteries for its high thermal stability and theoretical capacity of 336 mA h g −1 and low price, its inflexibility and sluggish lithium intercalation kinetics of bulk phase strongly limit its practical application for particular in thin-film electrode. Here we show a simple way to prepare highly flexible self-standing thin-film electrodes composed of mesoporous rutile TiO 2 /C nanofibers with low carbon content ( 2 in as-fabricated nanofibers. Big size (10 cm × 4 cm), flexible thin film is obtained after heat treatment under 10%H 2 –Ar at 900 °C for 3 h. After optimization, the diameter of fibers can reach as small as ∼110 nm, and the as-prepared rutile TiO 2 films show high initial electrochemical activity with the first discharge capacity as high as 388 mA h g −1 . What is more, very stable reversible capacities of ∼122, 92, and 70 mA h g −1 are achieved respectively at 1, 5 and 10 C rates with negligible decay rate within 100 cycling times.

  3. A rigorous analysis of high-order electromagnetic invisibility cloaks

    International Nuclear Information System (INIS)

    Weder, Ricardo

    2008-01-01

    There is currently a great deal of interest in the invisibility cloaks recently proposed by Pendry et al that are based on the transformation approach. They obtained their results using first-order transformations. In recent papers, Hendi et al and Cai et al considered invisibility cloaks with high-order transformations. In this paper, we study high-order electromagnetic invisibility cloaks in transformation media obtained by high-order transformations from general anisotropic media. We consider the case where there is a finite number of spherical cloaks located in different points in space. We prove that for any incident plane wave, at any frequency, the scattered wave is identically zero. We also consider the scattering of finite-energy wave packets. We prove that the scattering matrix is the identity, i.e., that for any incoming wave packet the outgoing wave packet is the same as the incoming one. This proves that the invisibility cloaks cannot be detected in any scattering experiment with electromagnetic waves in high-order transformation media, and in particular in the first-order transformation media of Pendry et al. We also prove that the high-order invisibility cloaks, as well as the first-order ones, cloak passive and active devices. The cloaked objects completely decouple from the exterior. Actually, the cloaking outside is independent of what is inside the cloaked objects. The electromagnetic waves inside the cloaked objects cannot leave the concealed regions and vice versa, the electromagnetic waves outside the cloaked objects cannot go inside the concealed regions. As we prove our results for media that are obtained by transformation from general anisotropic materials, we prove that it is possible to cloak objects inside general crystals

  4. Templating mesoporous zeolites

    DEFF Research Database (Denmark)

    Egeblad, Kresten; Christensen, Christina Hviid; Kustova, Marina

    2008-01-01

    The application of templating methods to produce zeolite materials with hierarchical bi- or trimodal pore size distributions is reviewed with emphasis on mesoporous materials. Hierarchical zeolite materials are categorized into three distinctly different types of materials: hierarchical zeolite...... crystals, nanosized zeolite crystals, and supported zeolite crystals. For the pure zeolite materials in the first two categories, the additional meso- or macroporosity can be classified as being either intracrystalline or intercrystalline, whereas for supported zeolite materials, the additional porosity...... originates almost exclusively from the support material. The methods for introducing mesopores into zeolite materials are discussed and categorized. In general, mesopores can be templated in zeolite materials by use of solid templating, supramolecular templating, or indirect templating...

  5. Mesoporous Ruthenium/Ruthenium Oxide Thin Films: Active Electrocatalysts for the Oxygen Evolution Reaction

    DEFF Research Database (Denmark)

    Kibsgaard, Jakob; Hellstern, Thomas R.; Choi, Shin-Jung

    2017-01-01

    We report the first synthesis of a fully contiguous large area supported thin film of highly ordered mesoporous Ru and RuO2 and investigate the electrocatalytic properties towards the oxygen evolution reaction (OER). We find that the nanoscale porous network of these catalysts provides significant...... enhancements in geometric OER activity without any loss in specific activity. This work demonstrates a strategy for engineering materials at the nanoscale that can simultaneously decrease precious metal loading and increase electrode activity....

  6. High Order Differential Frequency Hopping: Design and Analysis

    Directory of Open Access Journals (Sweden)

    Yong Li

    2015-01-01

    Full Text Available This paper considers spectrally efficient differential frequency hopping (DFH system design. Relying on time-frequency diversity over large spectrum and high speed frequency hopping, DFH systems are robust against hostile jamming interference. However, the spectral efficiency of conventional DFH systems is very low due to only using the frequency of each channel. To improve the system capacity, in this paper, we propose an innovative high order differential frequency hopping (HODFH scheme. Unlike in traditional DFH where the message is carried by the frequency relationship between the adjacent hops using one order differential coding, in HODFH, the message is carried by the frequency and phase relationship using two-order or higher order differential coding. As a result, system efficiency is increased significantly since the additional information transmission is achieved by the higher order differential coding at no extra cost on either bandwidth or power. Quantitative performance analysis on the proposed scheme demonstrates that transmission through the frequency and phase relationship using two-order or higher order differential coding essentially introduces another dimension to the signal space, and the corresponding coding gain can increase the system efficiency.

  7. High-rate capability of three-dimensionally ordered macroporous T-Nb2O5 through Li+ intercalation pseudocapacitance

    Science.gov (United States)

    Lou, Shuaifeng; Cheng, Xinqun; Wang, Long; Gao, Jinlong; Li, Qin; Ma, Yulin; Gao, Yunzhi; Zuo, Pengjian; Du, Chunyu; Yin, Geping

    2017-09-01

    Orthorhombic Niobium oxide (T-Nb2O5) has been regarded as a promising anode material for high-rate lithium ion batteries (LIBs) due to its potential to operate at high rates with improved safety and high theoretical capacity of 200 mA h g-1. Herein, three-dimensionally ordered macroporous (3DOM) T-Nb2O5, with mesoporous hierarchical structure, was firstly prepared by a simple approach employing self-assembly polystyrene (PS) microspheres as hard templates. The obtained T-Nb2O5 anode material presents obvious and highly-efficiency pseudocapacitive Li+ intercalation behaviour, which plays a dominant role in the kinetics of electrode process. As a result, rapid Li+ intercalation/de-intercalation are achieved, leading to excellent rate capability and long cycle life. The 3DOM T-Nb2O5 shows a remarkable high capacity of 106 and 77 mA h g-1 at the rate of 20C and 50C. The work presented herein holds great promise for future design of material structure, and demonstrates the great potential of T-Nb2O5 as a practical high-rate anode material for LIBs.

  8. Dynamic Stability Analysis Using High-Order Interpolation

    Directory of Open Access Journals (Sweden)

    Juarez-Toledo C.

    2012-10-01

    Full Text Available A non-linear model with robust precision for transient stability analysis in multimachine power systems is proposed. The proposed formulation uses the interpolation of Lagrange and Newton's Divided Difference. The High-Order Interpolation technique developed can be used for evaluation of the critical conditions of the dynamic system.The technique is applied to a 5-area 45-machine model of the Mexican interconnected system. As a particular case, this paper shows the application of the High-Order procedure for identifying the slow-frequency mode for a critical contingency. Numerical examples illustrate the method and demonstrate the ability of the High-Order technique to isolate and extract temporal modal behavior.

  9. A high order solver for the unbounded Poisson equation

    DEFF Research Database (Denmark)

    Hejlesen, Mads Mølholm; Rasmussen, Johannes Tophøj; Chatelain, Philippe

    2013-01-01

    . The method is extended to directly solve the derivatives of the solution to Poissonʼs equation. In this way differential operators such as the divergence or curl of the solution field can be solved to the same high order convergence without additional computational effort. The method, is applied......A high order converging Poisson solver is presented, based on the Greenʼs function solution to Poissonʼs equation subject to free-space boundary conditions. The high order convergence is achieved by formulating regularised integration kernels, analogous to a smoothing of the solution field...... and validated, however not restricted, to the equations of fluid mechanics, and can be used in many applications to solve Poissonʼs equation on a rectangular unbounded domain....

  10. Improved Stabilities of Immobilized Glucoamylase on Functionalized Mesoporous Silica Synthesised using Decane as Swelling Agent

    Directory of Open Access Journals (Sweden)

    Reni George

    2013-06-01

    Full Text Available Ordered mesoporous silica, with high porosity was used to immobilize glucoamylase via adsorption and covalent binding. Immobilization of glucoamylase within mesoporous silica was successfully achieved, resulting in catalytically high efficiency during starch hydrolysis. In this study, mesoporous silica was functionalized by co-condensation of tetraethoxysilane (TEOS with organosilane (3-aminopropyl triethoxysilane (APTES in a wide range of molar ratios of APTES: TEOS in the presence of triblock copolymer P123 under acidic hydrothermal conditions. The prepared materials were characterized by Small angle XRD, Nitrogen adsorption – desorption and 29Si MAS solid state NMR. N2 desorption studies showed that pore size distribution decreases due to pore blockage after functionalization and enzyme immobilization. Small angle XRD and 29Si MAS NMR study reveals mesophase formation and Si environment of the materials. The main aim of our work was to study the catalytical activity, effect of pH, temperature storage stability and reusability of covalently bound glucoamylase on mesoporous silica support. The result shows that the stability of enzyme can be enhanced by immobilization.  © 2013 BCREC UNDIP. All rights reservedReceived: 3rd December 2012; Revised: 4th April 2013; Accepted: 20th April 2013[How to Cite: George, R., Gopinath, S., Sugunan, S. (2013. Improved Stabilities of Immobilized Glucoamyl-ase on Functionalized Mesoporous Silica Synthesized using Decane as Swelling Agent. Bulletin of Chemical Reaction Engineering & Catalysis, 8 (1: 70-76. (doi:10.9767/bcrec.8.1.4208.70-76][Permalink/DOI: http://dx.doi.org/10.9767/bcrec.8.1.4208.70-76] | View in  |

  11. Synthesis of MgO nanoparticle loaded mesoporous Al2O3 and its defluoridation study

    International Nuclear Information System (INIS)

    Dayananda, Desagani; Sarva, Venkateswara R.; Prasad, Sivankutty V.; Arunachalam, Jayaraman; Parameswaran, Padmanabhan; Ghosh, Narendra N.

    2015-01-01

    Highlights: • Simple and cost effective preparation of MgO nanoparticles loaded mesoporous Al 2 O 3 . • Adsorbents possess high surface area and mesoporous structure. • Higher fluoride removal capacity of MgO loaded Al 2 O 3 than that of pure Al 2 O 3 . • Faster fluoride adsorption kinetics of MgO loaded Al 2 O 3 from water. - Abstract: MgO nanoparticle loaded mesoporous alumina has been synthesized using a simple aqueous solution based cost effective method for removal of fluoride from water. Wide angle powder X-ray diffraction, nitrogen adsorption desorption analysis, transmission electron microscopy techniques and energy dispersive X-ray spectroscopy were used to characterize the synthesized adsorbents. Synthesized adsorbents possess high surface area with mesoporous structure. The adsorbents have been thoroughly investigated for the adsorption of F − using batch adsorption method. MgO nanoparticle loading on mesoporous Al 2 O 3 enhances the F − adsorption capacity of Al 2 O 3 from 56% to 90% (initial F − concentration = 10 mg L −1 ). Kinetic study revealed that adsorption kinetics follows the pseudo-second order model, suggesting the chemisorption mechanism. The F − adsorption isotherm data was explained by both Langmuir and Freundlich model. The maximum adsorption capacity of 40MgO@Al 2 O 3 was 37.35 mg g −1 . It was also observed that, when the solutions having F − concentration of 5 mg L −1 and 10 mg L −1 was treated with 40MgO@Al 2 O 3 , the F − concentration in treated water became <1 mg L −1 , which is well below the recommendation of WHO

  12. Low-temperature fabrication of mesoporous solid strong bases by using multifunction of a carbon interlayer.

    Science.gov (United States)

    Liu, Xiao-Yan; Sun, Lin-Bing; Liu, Xiao-Dan; Li, Ai-Guo; Lu, Feng; Liu, Xiao-Qin

    2013-10-09

    Mesoporous solid strong bases are highly promising for applications as environmentally benign catalysts in various reactions. Their preparation attracts increasing attention for the demand of sustainable chemistry. In the present study, a new strategy was designed to fabricate strong basicity on mesoporous silica by using multifunction of a carbon interlayer. A typical mesoporous silica, SBA-15, was precoated with a layer of carbon prior to the introduction of base precursor LiNO3. The carbon interlayer performs two functions by promoting the conversion of LiNO3 at low temperatures and by improving the alkali-resistant ability of siliceous host. Only a tiny amount of LiNO3 was decomposed on pristine SBA-15 at 400 °C; for the samples containing >8 wt % of carbon, however, LiNO3 can be entirely converted to strongly basic sites Li2O under the same conditions. The guest-host redox reaction was proven to be the answer for the conversion of LiNO3, which breaks the tradition of thermally induced decomposition. More importantly, the residual carbon layer can prevent the siliceous frameworks from corroding by the newly formed strongly basic species, which is different from the complete destruction of mesostructure in the absence of carbon. Therefore, materials possessing both ordered mesostructure and strong basicity were successfully fabricated, which is extremely desirable for catalysis and impossible to realize by conventional methods. We also demonstrated that the resultant mesoporous basic materials are active in heterogeneous synthesis of dimethyl carbonate (DMC) and the yield of DMC can reach 32.4%, which is apparently higher than that over the catalysts without a carbon interlayer (<12.9%) despite the same lithium content. The strong basicity, in combination with the uniform mesopores, is believed to be responsible for such a high activity.

  13. Interface chemistry of nanostructured materials: ion adsorption on mesoporous alumina.

    Science.gov (United States)

    Wang, Yifeng; Bryan, Charles; Xu, Huifang; Pohl, Phil; Yang, Yi; Brinker, C Jeffrey

    2002-10-01

    This paper presents a part of our work on understanding the effect of nanoscale pore space confinement on ion sorption by mesoporous materials. Acid-base titration experiments were performed on both mesoporous alumina and alumina particles under various ionic strengths. The point of zero charge (PZC) for mesoporous alumina was measured to be approximately 9.1, similar to that for nonmesoporous alumina materials, indicating that nanoscale pore space confinement does not have a significant effect on the PZC of pore surfaces. However, for a given pH deviation from the PZC, (pH-PZC), the surface charge per mass on mesoporous alumina was as much as 45 times higher than that on alumina particles. This difference cannot be fully explained by the surface area difference between the two materials. Our titration data have demonstrated that nanoscale confinement has a significant effect, most likely via the overlap of the electric double layer (EDL), on ion sorption onto mesopore surfaces. This effect cannot be adequately modeled by existing surface complexation models, which were developed mostly for an unconfined solid-water interface. Our titration data have also indicated that the rate of ion uptake by mesoporous alumina is relatively slow, probably due to diffusion into mesopores, and complete equilibration for sorption could take 4-5 min. A molecular simulation using a density functional theory was performed to calculate ion adsorption coefficients as a function of pore size. The calculation has shown that as pore size is reduced to nanoscales (<10 nm), the adsorption coefficients of ions can vary by more than two orders of magnitude relative to those for unconfined interfaces. The prediction is supported by our experimental data on Zn sorption onto mesoporous alumina. Owing to their unique surface chemistry, mesoporous materials can potentially be used as effective ion adsorbents for separation processes and environmental cleanup.

  14. Retrieval of high-order susceptibilities of nonlinear metamaterials

    International Nuclear Information System (INIS)

    Wang Zhi-Yu; Qiu Jin-Peng; Chen Hua; Mo Jiong-Jiong; Yu Fa-Xin

    2017-01-01

    Active metamaterials embedded with nonlinear elements are able to exhibit strong nonlinearity in microwave regime. However, existing S -parameter based parameter retrieval approaches developed for linear metamaterials do not apply in nonlinear cases. In this paper, a retrieval algorithm of high-order susceptibilities for nonlinear metamaterials is derived. Experimental demonstration shows that, by measuring the power level of each harmonic while sweeping the incident power, high-order susceptibilities of a thin-layer nonlinear metamaterial can be effectively retrieved. The proposedapproach can be widely used in the research of active metamaterials. (paper)

  15. High-order harmonic generation with short-pulse lasers

    International Nuclear Information System (INIS)

    Schafer, K.J.; Krause, J.L.; Kulander, K.C.

    1992-12-01

    Recent progress in the understanding of high-order harmonic conversion from atoms and ions exposed to high-intensity, short-pulse optical lasers is reviewed. We find that ions can produce harmonics comparable in strength to those obtained from neutral atoms, and that the emission extends to much higher order. Simple scaling laws for the strength of the harmonic emission and the maximium observable harmonic are suggested. These results imply that the photoemission observed in recent experiments in helium and neon contains contributions from ions as well as neutrals

  16. Ductile long range ordered alloys with high critical ordering temperature and wrought articles fabricated therefrom

    Science.gov (United States)

    Liu, Chain T.; Inouye, Henry

    1979-01-01

    Malleable long range ordered alloys having high critical ordering temperatures exist in the V(Fe, Co).sub.3 and V(Fe, Co, Ni).sub.3 systems. These alloys have the following compositions comprising by weight: 22-23% V, 14-30% Fe, and the remainder Co or Co and Ni with an electron density no more than 7.85. The maximum combination of high temperature strength, ductility and creep resistance are manifested in the alloy comprising by weight 22-23% V, 14-20% Fe and the remainder Co and having an atomic composition of V(Fe .sub.0.20-0.26 C Co.sub.0.74-0.80).sub.3. The alloy comprising by weight 22-23% V, 16-17% Fe and 60-62% Co has excellent high temperature properties. The alloys are fabricable into wrought articles by casting, deforming, and annealing for sufficient time to provide ordered structure.

  17. High-Order Curvilinear Finite Element Methods for Lagrangian Hydrodynamics [High Order Curvilinear Finite Elements for Lagrangian Hydrodynamics

    Energy Technology Data Exchange (ETDEWEB)

    Dobrev, Veselin A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Kolev, Tzanio V. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Rieben, Robert N. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2012-09-20

    The numerical approximation of the Euler equations of gas dynamics in a movingLagrangian frame is at the heart of many multiphysics simulation algorithms. Here, we present a general framework for high-order Lagrangian discretization of these compressible shock hydrodynamics equations using curvilinear finite elements. This method is an extension of the approach outlined in [Dobrev et al., Internat. J. Numer. Methods Fluids, 65 (2010), pp. 1295--1310] and can be formulated for any finite dimensional approximation of the kinematic and thermodynamic fields, including generic finite elements on two- and three-dimensional meshes with triangular, quadrilateral, tetrahedral, or hexahedral zones. We discretize the kinematic variables of position and velocity using a continuous high-order basis function expansion of arbitrary polynomial degree which is obtained via a corresponding high-order parametric mapping from a standard reference element. This enables the use of curvilinear zone geometry, higher-order approximations for fields within a zone, and a pointwise definition of mass conservation which we refer to as strong mass conservation. Moreover, we discretize the internal energy using a piecewise discontinuous high-order basis function expansion which is also of arbitrary polynomial degree. This facilitates multimaterial hydrodynamics by treating material properties, such as equations of state and constitutive models, as piecewise discontinuous functions which vary within a zone. To satisfy the Rankine--Hugoniot jump conditions at a shock boundary and generate the appropriate entropy, we introduce a general tensor artificial viscosity which takes advantage of the high-order kinematic and thermodynamic information available in each zone. Finally, we apply a generic high-order time discretization process to the semidiscrete equations to develop the fully discrete numerical algorithm. Our method can be viewed as the high-order generalization of the so-called staggered

  18. Hybrid RANS-LES using high order numerical methods

    Science.gov (United States)

    Henry de Frahan, Marc; Yellapantula, Shashank; Vijayakumar, Ganesh; Knaus, Robert; Sprague, Michael

    2017-11-01

    Understanding the impact of wind turbine wake dynamics on downstream turbines is particularly important for the design of efficient wind farms. Due to their tractable computational cost, hybrid RANS/LES models are an attractive framework for simulating separation flows such as the wake dynamics behind a wind turbine. High-order numerical methods can be computationally efficient and provide increased accuracy in simulating complex flows. In the context of LES, high-order numerical methods have shown some success in predictions of turbulent flows. However, the specifics of hybrid RANS-LES models, including the transition region between both modeling frameworks, pose unique challenges for high-order numerical methods. In this work, we study the effect of increasing the order of accuracy of the numerical scheme in simulations of canonical turbulent flows using RANS, LES, and hybrid RANS-LES models. We describe the interactions between filtering, model transition, and order of accuracy and their effect on turbulence quantities such as kinetic energy spectra, boundary layer evolution, and dissipation rate. This work was funded by the U.S. Department of Energy, Exascale Computing Project, under Contract No. DE-AC36-08-GO28308 with the National Renewable Energy Laboratory.

  19. A Brown Mesoporous TiO2-x /MCF Composite with an Extremely High Quantum Yield of Solar Energy Photocatalysis for H2 Evolution.

    Science.gov (United States)

    Xing, Mingyang; Zhang, Jinlong; Qiu, Bocheng; Tian, Baozhu; Anpo, Masakazu; Che, Michel

    2015-04-24

    A brown mesoporous TiO2-x /MCF composite with a high fluorine dopant concentration (8.01 at%) is synthesized by a vacuum activation method. It exhibits an excellent solar absorption and a record-breaking quantum yield (Φ = 46%) and a high photon-hydrogen energy conversion efficiency (η = 34%,) for solar photocatalytic H2 production, which are all higher than that of the black hydrogen-doped TiO2 (Φ = 35%, η = 24%). The MCFs serve to improve the adsorption of F atoms onto the TiO2 /MCF composite surface, which after the formation of oxygen vacancies by vacuum activation, facilitate the abundant substitution of these vacancies with F atoms. The decrease of recombination sites induced by high-concentration F doping and the synergistic effect between lattice Ti(3+)-F and surface Ti(3+)-F are responsible for the enhanced lifetime of electrons, the observed excellent absorption of solar light, and the photocatalytic production of H2 for these catalysts. The as-prepared F-doped composite is an ideal solar light-driven photocatalyst with great potential for applications ranging from the remediation of environmental pollution to the harnessing of solar energy for H2 production. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Protein-gold clusters-capped mesoporous silica nanoparticles for high drug loading, autonomous gemcitabine/doxorubicin co-delivery, and in-vivo tumor imaging

    KAUST Repository

    Croissant, Jonas G.; Zhang, Dingyuan; Alsaiari, Shahad K.; Lu, Jie; Deng, Lin; Tamanoi, Fuyuhiko; Zink, Jeffrey I.; Khashab, Niveen M.

    2016-01-01

    Functional nanocarriers capable of transporting high drug contents without premature leakage and to controllably deliver several drugs are needed for better cancer treatments. To address this clinical need, gold cluster bovine serum albumin (AuNC@BSA) nanogates were engineered on mesoporous silica nanoparticles (MSN) for high drug loadings and co-delivery of two different anticancer drugs. The first drug, gemcitabine (GEM, 40 wt%), was loaded in positively-charged ammonium-functionalized MSN (MSN-NH3+). The second drug, doxorubicin (DOX, 32 wt%), was bound with negatively-charged AuNC@BSA electrostatically-attached onto MSN-NH3+, affording highly loaded pH-responsive MSN-AuNC@BSA nanocarriers. The co-delivery of DOX and GEM was achieved for the first time via an inorganic nanocarrier, possessing a zero-premature leakage behavior as well as drug loading capacities seven times higher than polymersome NPs. Besides, unlike the majority of strategies used to cap the pores of MSN, AuNC@BSA nanogates are biotools and were applied for targeted red nuclear staining and in-vivo tumor imaging. The straightforward non-covalent combination of MSN and gold-protein cluster bioconjugates thus leads to a simple, yet multifunctional nanotheranostic for the next generation of cancer treatments.

  1. Protein-gold clusters-capped mesoporous silica nanoparticles for high drug loading, autonomous gemcitabine/doxorubicin co-delivery, and in-vivo tumor imaging

    KAUST Repository

    Croissant, Jonas G.

    2016-03-23

    Functional nanocarriers capable of transporting high drug contents without premature leakage and to controllably deliver several drugs are needed for better cancer treatments. To address this clinical need, gold cluster bovine serum albumin (AuNC@BSA) nanogates were engineered on mesoporous silica nanoparticles (MSN) for high drug loadings and co-delivery of two different anticancer drugs. The first drug, gemcitabine (GEM, 40 wt%), was loaded in positively-charged ammonium-functionalized MSN (MSN-NH3+). The second drug, doxorubicin (DOX, 32 wt%), was bound with negatively-charged AuNC@BSA electrostatically-attached onto MSN-NH3+, affording highly loaded pH-responsive MSN-AuNC@BSA nanocarriers. The co-delivery of DOX and GEM was achieved for the first time via an inorganic nanocarrier, possessing a zero-premature leakage behavior as well as drug loading capacities seven times higher than polymersome NPs. Besides, unlike the majority of strategies used to cap the pores of MSN, AuNC@BSA nanogates are biotools and were applied for targeted red nuclear staining and in-vivo tumor imaging. The straightforward non-covalent combination of MSN and gold-protein cluster bioconjugates thus leads to a simple, yet multifunctional nanotheranostic for the next generation of cancer treatments.

  2. 一步法合成载铁有序介孔碳材料的形成机理%Mechanism of the synthesis of ordered Fe-containing mesoporous carbon composite materials in one-pot

    Institute of Scientific and Technical Information of China (English)

    凌晓凤; 顾娟; 李健生; 孙秀云; 韩卫清; 沈锦优; 王连军

    2012-01-01

    采用软模板路线以三嵌段共聚物F127为模板剂,间苯二酚-甲醛缩聚所形成酚醛树脂(RF)为碳源,与酚羟基有络合作用的无机铁盐为金属前体,在无外加酸碱催化剂的条件下,利用铁盐的水解反应形成酚醛缩聚所需酸性环境,多组分共组装一步合成了载铁有序介孔碳材料(Fe/OMC)。对Fe/OMC合成各阶段过程进行了分析,利用X射线衍射、透射电子显微镜等手段对材料进行表征,比较了不同老化时间、硝酸铁投加量及酚醛比例等合成条件对材料结构的影响规律。结果表明,在较长的老化时间(≥60 h)、适宜的n(Fe)/n(R)比(0.05~0.2)和n(R)/n(F)比[(1/1.5)~(1/2)]条件下,均可形成有序的介孔结构。在此基础上,提出了载铁有序介孔碳材料的形成机理。%Ordered Fe-containing mesoporous carbon composite materials(Fe/OMC)have been synthesized via soft-templating routes by using triblock copolymer F127 as a template agent,resorcinol(R)-formaldehyde(F)as a carbon precursor,inorganic iron salts having complex reaction with phenols as a metal precursor in one-pot.The main strategy of this approach was to utilize the acidity self-generated from the hydrolysis of inorganic salts in the aqueous solutions as the catalyst for RF polymerization,where no addition of mineral acids was necessary.The resultant Fe/OMC materials were characterized by X-ray diffraction,Transmission electron microscopy.The influences of the aging time,the dosage of iron nitrate and the molar ratio of R/F on the structure of the obtained materials were investigated.Results show that the ordered mesoporous structure can be obtained under the synthetic condition of the aging time≥60 h,n(Fe)/n(R)=0.05— 0.2,n(R)/n(F)=1/1.5— 1/2.0.Moreover,a possible mechanism of the synthesis of Fe/OMC was proposed.

  3. Eliminating high-order scattering effects in optical microbubble sizing.

    Science.gov (United States)

    Qiu, Huihe

    2003-04-01

    Measurements of bubble size and velocity in multiphase flows are important in much research and many industrial applications. It has been found that high-order refractions have great impact on microbubble sizing by use of phase-Doppler anemometry (PDA). The problem has been investigated, and a model of phase-size correlation, which also takes high-order refractions into consideration, is introduced to improve the accuracy of bubble sizing. Hence the model relaxes the assumption of a single-scattering mechanism in a conventional PDA system. The results of simulation based on this new model are compared with those based on a single-scattering-mechanism approach or a first-order approach. An optimization method for accurately sizing air bubbles in water has been suggested.

  4. Nanostructured nitrogen-doped mesoporous carbon derived from polyacrylonitrile for advanced lithium sulfur batteries

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Ying; Zhao, Xiaohui; Chauhan, Ghanshyam S. [Department of Chemical Engineering and Research Institute for Green Energy Convergence Technology, Gyeongsang National University, 501 Jinju-daero, Jinju 660-701 (Korea, Republic of); Ahn, Jou-Hyeon, E-mail: jhahn@gnu.ac.kr [Department of Chemical Engineering and Research Institute for Green Energy Convergence Technology, Gyeongsang National University, 501 Jinju-daero, Jinju 660-701 (Korea, Republic of); Department of Materials Engineering and Convergence Technology and RIGET, Gyeongsang National University, 501 Jinju-daero, Jinju 660-701 (Korea, Republic of)

    2016-09-01

    Graphical abstract: Well-ordered nitrogen-doped mesoporous carbon materials were prepared by in-situ polymerization of polyacrylonitrile in SBA-15 template. The composite of sulfur and nitrogen-doped carbon was successfully used as a cathode material for lithium sulfur battery. - Highlights: • N-doped mesoporous carbons were prepared with PAN as carbon source. • Highly ordered pore system facilitates sulfur loading. • Ladder-type carbon matrix provides good structural stability for confining sulfur. • N-doping ensures an improved absorbability of soluble polysulfides. - Abstract: Nitrogen doping in carbon matrix can effectively improve the wettability of electrolyte and increase electric conductivity of carbon by ensuring fast transfer of ions. We synthesized a series of nitrogen-doped mesoporous carbons (CPANs) via in situ polymerization of polyacrylonitrile (PAN) in SBA-15 template followed by carbonization at different temperatures. Carbonization results in the formation of ladder structure which enhances the stability of the matrix. In this study, CPAN-800, carbon matrix synthesized by the carbonization at 800 °C, was found to possess many desirable properties such as high specific surface area and pore volume, moderate nitrogen content, and highly ordered mesoporous structure. Therefore, it was used to prepare S/CPAN-800 composite as cathode material in lithium sulfur (Li-S) batteries. The S/CPAN-800 composite was proved to be an excellent material for Li-S cells which delivered a high initial discharge capacity of 1585 mAh g{sup −1} and enhanced capacity retention of 862 mAh g{sup −1} at 0.1 C after 100 cycles.

  5. International Conference on Spectral and High-Order Methods

    CERN Document Server

    Dumont, Ney; Hesthaven, Jan

    2017-01-01

    This book features a selection of high-quality papers chosen from the best presentations at the International Conference on Spectral and High-Order Methods (2016), offering an overview of the depth and breadth of the activities within this important research area. The carefully reviewed papers provide a snapshot of the state of the art, while the extensive bibliography helps initiate new research directions.

  6. A high order solver for the unbounded Poisson equation

    DEFF Research Database (Denmark)

    Hejlesen, Mads Mølholm; Rasmussen, Johannes Tophøj; Chatelain, Philippe

    2012-01-01

    This work improves upon Hockney and Eastwood's Fourier-based algorithm for the unbounded Poisson equation to formally achieve arbitrary high order of convergence without any additional computational cost. We assess the methodology on the kinematic relations between the velocity and vorticity fields....

  7. factor high order fuzzy time series with applications to temperature

    African Journals Online (AJOL)

    HOD

    In this paper, a novel two – factor highorder fuzzy time series forecasting method based on .... to balance between local and global exploitations of the swarms. While, .... Although, there were a number of outliers but, the spread at the spot in ...

  8. In-situ growth of LiFePO4 nanocrystals on interconnected carbon nanotubes/mesoporous carbon nanosheets for high-performance lithium ion batteries

    International Nuclear Information System (INIS)

    Wu, Ruofei; Xia, Guofeng; Shen, Shuiyun; Zhu, Fengjuan; Jiang, Fengjing; Zhang, Junliang

    2015-01-01

    Graphical abstract: In-situ soft-templated LFP nanocrystals on interconnected carbon nanotubes/mesoporous carbon nanosheets (designated as LFP@CNTs/CNSs), exhibited superior electrochemical performance due to the synergetic effect between CNTs and CNSs, which form interconnected conductive network for fast transport of both electrons and lithium ions. - Highlights: • LFP nanocrystals were in-situ synthesized on interconnected CNTs/CNSs framework with an in-situ soft-templated method. • LFP@CNTs/CNSs exhibited superior rate capability and cycling stability, due to interconnected conductive network for fast transport of both electrons and lithium ions. • The synergetic effect between CNTs and CNSs on the electrochemical performance of LFP electrode was demonstrated by a systematically electrochemical study compared with LFP/CNSs and LFP/CNTs. - Abstract: Lithium ion phosphate (LiFePO 4 ) nanocrystals are successfully in-situ grown on interconnected carbon nanotubes/mesoporous carbon nanosheets (designated as LFP@CNTs/CNSs) with a soft-templated method, which involves the multi-constituent co-assembly of a triblock copolymer, CNTs, resol and precursors of LFP followed by thermal treatment. X-ray diffraction, scanning electron microscopy, high resolution transmission electron microscopy and N 2 adsorption-desorption techniques are used to characterize the structure and morphology of the as-synthesized materials. When used as the cathode of lithium ion batteries, the LFP@CNTs/CNSs composite exhibits superior rate capability and cycling stability, compared with the samples modified only with CNSs (designated as LFP/CNSs) or with CNTs (designated as LFP/CNTs). This is mainly attributed to the synergetic effect between CNTs and CNSs caused by their unique structure, which forms interconnected conductive network for fast transport of both electrons and lithium ions, and thus remarkably improves the electrode kinetics. Firstly, nano-sized LFP are in-situ grown on the

  9. Near-infrared emission from mesoporous crystalline germanium

    Energy Technology Data Exchange (ETDEWEB)

    Boucherif, Abderraouf; Aimez, Vincent; Arès, Richard, E-mail: richard.ares@usherbrooke.ca [Institut Interdisciplinaire d’Innovation Technologique (3IT), Université de Sherbrooke, 3000 Boulevard Université, Sherbrooke, J1K OA5, Québec (Canada); Laboratoire Nanotechnologies Nanosystèmes (LN2)-CNRS UMI-3463, Université de Sherbrooke, 3000 Boulevard Université, Sherbrooke, J1K OA5, Québec (Canada); Korinek, Andreas [Canadian Centre for Electron Microscopy, Brockhouse Institute for Materials Research, McMaster University, Hamilton, Ontario, L8S 4M1 (Canada)

    2014-10-15

    Mesoporous crystalline germanium was fabricated by bipolar electrochemical etching of Ge wafer in HF-based electrolyte. It yields uniform mesoporous germanium layers composed of high density of crystallites with an average size 5-7 nm. Subsequent extended chemical etching allows tuning of crystallites size while preserving the same chemical composition. This highly controllable nanostructure exhibits photoluminescence emission above the bulk Ge bandgap, in the near-infrared range (1095-1360nm) with strong evidence of quantum confinement within the crystallites.

  10. High-order perturbations of a spherical collapsing star

    International Nuclear Information System (INIS)

    Brizuela, David; Martin-Garcia, Jose M.; Sperhake, Ulrich; Kokkotas, Kostas D.

    2010-01-01

    A formalism to deal with high-order perturbations of a general spherical background was developed in earlier work [D. Brizuela, J. M. Martin-Garcia, and G. A. Mena Marugan, Phys. Rev. D 74, 044039 (2006); D. Brizuela, J. M. Martin-Garcia, and G. A. Mena Marugan, Phys. Rev. D 76, 024004 (2007)]. In this paper, we apply it to the particular case of a perfect fluid background. We have expressed the perturbations of the energy-momentum tensor at any order in terms of the perturbed fluid's pressure, density, and velocity. In general, these expressions are not linear and have sources depending on lower-order perturbations. For the second-order case we make the explicit decomposition of these sources in tensor spherical harmonics. Then, a general procedure is given to evolve the perturbative equations of motions of the perfect fluid for any value of the harmonic label. Finally, with the problem of a spherical collapsing star in mind, we discuss the high-order perturbative matching conditions across a timelike surface, in particular, the surface separating the perfect fluid interior from the exterior vacuum.

  11. Ultrasmall Tin Nanodots Embedded in Nitrogen-Doped Mesoporous Carbon: Metal-Organic-Framework Derivation and Electrochemical Application as Highly Stable Anode for Lithium Ion Batteries

    International Nuclear Information System (INIS)

    Dai, Ruoling; Sun, Weiwei; Wang, Yong

    2016-01-01

    Highlights: • Sn-based metal-organic-framework (MOF) is prepared. • Ultrasmall tin nanodots (2–3 nm) are embedded in nitrogen-doped mesoporous carbon. • The Sn/C composite anode shows high capacity and ultralong cycle life. - Abstract: This work reports a facile metal-organic-framework based approach to synthesize Sn/C composite, in which ultrasmall Sn nanodots with typical size of 2–3 nm are uniformly embedded in the nitrogen-doped porous carbon matrix (denoted as Sn@NPC). The effect of thermal treatment and nitrogen doping are also explored. Owing to the delicate size control and confined volume change within carbon matrix, the Sn@NPC composite can exhibit reversible capacities of 575 mAh g −1 (Sn contribution: 1091 mAh g −1 ) after 500 cycles at 0.2 A g −1 and 507 mAh g −1 (Sn contribution: 1077 mAh g −1 ) after 1500 cycles at 1 A g −1 . The excellent long-life electrochemical stability of the Sn@NPC anode has been mainly attributed to the uniform distribution of ultrasmall Sn nanodots and the highly-conductive and flexible N-doped carbon matrix, which can effectively facilitate lithium ion/electron diffusion, buffer the large volume change and improve the structure stability of the electrode during repetitive cycling with lithium ions.

  12. Electro-spray deposition of a mesoporous TiO2 charge collection layer: toward large scale and continuous production of high efficiency perovskite solar cells.

    Science.gov (United States)

    Kim, Min-cheol; Kim, Byeong Jo; Yoon, Jungjin; Lee, Jin-wook; Suh, Dongchul; Park, Nam-gyu; Choi, Mansoo; Jung, Hyun Suk

    2015-12-28

    The spin-coating method, which is widely used for thin film device fabrication, is incapable of large-area deposition or being performed continuously. In perovskite hybrid solar cells using CH(3)NH(3)PbI(3) (MAPbI(3)), large-area deposition is essential for their potential use in mass production. Prior to replacing all the spin-coating process for fabrication of perovskite solar cells, herein, a mesoporous TiO(2) electron-collection layer is fabricated by using the electro-spray deposition (ESD) system. Moreover, impedance spectroscopy and transient photocurrent and photovoltage measurements reveal that the electro-sprayed mesoscopic TiO(2) film facilitates charge collection from the perovskite. The series resistance of the perovskite solar cell is also reduced owing to the highly porous nature of, and the low density of point defects in, the film. An optimized power conversion efficiency of 15.11% is achieved under an illumination of 1 sun; this efficiency is higher than that (13.67%) of the perovskite solar cell with the conventional spin-coated TiO(2) films. Furthermore, the large-area coating capability of the ESD process is verified through the coating of uniform 10 × 10 cm(2) TiO(2) films. This study clearly shows that ESD constitutes therefore a viable alternative for the fabrication of high-throughput, large-area perovskite solar cells.

  13. Hollow Mesoporous Silica Supported Ruthenium Nanoparticles: A Highly Active and Reusable Catalyst for H2 Generation from the Hydrolysis of NaBH4

    Directory of Open Access Journals (Sweden)

    Shuge Peng

    2015-01-01

    Full Text Available Ru nanoparticles supported on hollow mesoporous silica (HMS, which are prepared via in situ wet chemical reduction, have been investigated as the highly efficient heterogeneous catalyst for H2 generation from the hydrolysis of an alkaline NaBH4 solution. Many techniques, including X-ray diffraction (XRD, transmission electron microscope (TEM, and X-ray photoelectron spectroscopy (XPS, are used to characterize the as-prepared nanocatalyst (Ru/HMS. Factors, such as Ru loadings in HMS, catalyst concentration, and solution temperature, on catalytic property and reutilization are investigated in this work. A rate of H2 generation as high as 18.6 L min−1 g−1 (Ru using 1 wt% NaBH4 solution containing 3 wt% NaOH and 40 mg of Ru/HMS catalyst can be reached at room temperature. The minimum apparent activation energy (Ea of H2 generation, obtained by fitting the curve of Ea values versus catalyst amount, is determined to be 46.7 ± 1 kJ/mol. The residual catalytic activity of the repeated Ru/HMS still remains 47.7% after 15 runs, which perhaps results from the incorporation of the residual by-product (NaBO2 in the pores of HMS based on the analysis of XPS.

  14. HOKF: High Order Kalman Filter for Epilepsy Forecasting Modeling.

    Science.gov (United States)

    Nguyen, Ngoc Anh Thi; Yang, Hyung-Jeong; Kim, Sunhee

    2017-08-01

    Epilepsy forecasting has been extensively studied using high-order time series obtained from scalp-recorded electroencephalography (EEG). An accurate seizure prediction system would not only help significantly improve patients' quality of life, but would also facilitate new therapeutic strategies to manage epilepsy. This paper thus proposes an improved Kalman Filter (KF) algorithm to mine seizure forecasts from neural activity by modeling three properties in the high-order EEG time series: noise, temporal smoothness, and tensor structure. The proposed High-Order Kalman Filter (HOKF) is an extension of the standard Kalman filter, for which higher-order modeling is limited. The efficient dynamic of HOKF system preserves the tensor structure of the observations and latent states. As such, the proposed method offers two main advantages: (i) effectiveness with HOKF results in hidden variables that capture major evolving trends suitable to predict neural activity, even in the presence of missing values; and (ii) scalability in that the wall clock time of the HOKF is linear with respect to the number of time-slices of the sequence. The HOKF algorithm is examined in terms of its effectiveness and scalability by conducting forecasting and scalability experiments with a real epilepsy EEG dataset. The results of the simulation demonstrate the superiority of the proposed method over the original Kalman Filter and other existing methods. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. On high-order perturbative calculations at finite density

    CERN Document Server

    Ghisoiu, Ioan; Kurkela, Aleksi; Romatschke, Paul; Säppi, Matias; Vuorinen, Aleksi

    2017-01-01

    We discuss the prospects of performing high-order perturbative calculations in systems characterized by a vanishing temperature but finite density. In particular, we show that the determination of generic Feynman integrals containing fermionic chemical potentials can be reduced to the evaluation of three-dimensional phase space integrals over vacuum on-shell amplitudes. Applications of these rules will be discussed in the context of the thermodynamics of cold and dense QCD, where it is argued that they facilitate an extension of the Equation of State of cold quark matter to higher perturbative orders.

  16. On high-order perturbative calculations at finite density

    Energy Technology Data Exchange (ETDEWEB)

    Ghişoiu, Ioan, E-mail: ioan.ghisoiu@helsinki.fi [Helsinki Institute of Physics and Department of Physics, University of Helsinki (Finland); Gorda, Tyler, E-mail: tyler.gorda@helsinki.fi [Helsinki Institute of Physics and Department of Physics, University of Helsinki (Finland); Department of Physics, University of Colorado Boulder, Boulder, CO (United States); Kurkela, Aleksi, E-mail: aleksi.kurkela@cern.ch [Theoretical Physics Department, CERN, Geneva (Switzerland); Faculty of Science and Technology, University of Stavanger, Stavanger (Norway); Romatschke, Paul, E-mail: paul.romatschke@colorado.edu [Department of Physics, University of Colorado Boulder, Boulder, CO (United States); Center for Theory of Quantum Matter, University of Colorado, Boulder, CO (United States); Säppi, Matias, E-mail: matias.sappi@helsinki.fi [Helsinki Institute of Physics and Department of Physics, University of Helsinki (Finland); Vuorinen, Aleksi, E-mail: aleksi.vuorinen@helsinki.fi [Helsinki Institute of Physics and Department of Physics, University of Helsinki (Finland)

    2017-02-15

    We discuss the prospects of performing high-order perturbative calculations in systems characterized by a vanishing temperature but finite density. In particular, we show that the determination of generic Feynman integrals containing fermionic chemical potentials can be reduced to the evaluation of three-dimensional phase space integrals over vacuum on-shell amplitudes — a result reminiscent of a previously proposed “naive real-time formalism” for vacuum diagrams. Applications of these rules are discussed in the context of the thermodynamics of cold and dense QCD, where it is argued that they facilitate an extension of the Equation of State of cold quark matter to higher perturbative orders.

  17. Theoretical description of high-order harmonic generation in solids

    International Nuclear Information System (INIS)

    Kemper, A F; Moritz, B; Devereaux, T P; Freericks, J K

    2013-01-01

    We consider several aspects of high-order harmonic generation in solids: the effects of elastic and inelastic scattering, varying pulse characteristics and inclusion of material-specific parameters through a realistic band structure. We reproduce many observed characteristics of high harmonic generation experiments in solids including the formation of only odd harmonics in inversion-symmetric materials, and the nonlinear formation of high harmonics with increasing field. We find that the harmonic spectra are fairly robust against elastic and inelastic scattering. Furthermore, we find that the pulse characteristics can play an important role in determining the harmonic spectra. (paper)

  18. High-Performance Li-Ion Capacitor Based on an Activated Carbon Cathode and Well-Dispersed Ultrafine TiO2 Nanoparticles Embedded in Mesoporous Carbon Nanofibers Anode.

    Science.gov (United States)

    Yang, Cheng; Lan, Jin-Le; Liu, Wen-Xiao; Liu, Yuan; Yu, Yun-Hua; Yang, Xiao-Ping

    2017-06-07

    A novel Li-ion capacitor based on an activated carbon cathode and a well-dispersed ultrafine TiO 2 nanoparticles embedded in mesoporous carbon nanofibers (TiO 2 @PCNFs) anode was reported. A series of TiO 2 @PCNFs anode materials were prepared via a scalable electrospinning method followed by carbonization and a postetching method. The size of TiO 2 nanoparticles and the mesoporous structure of the TiO 2 @PCNFs were tuned by varying amounts of tetraethyl orthosilicate (TEOS) to increase the energy density and power density of the LIC significantly. Such a subtle designed LIC displayed a high energy density of 67.4 Wh kg -1 at a power density of 75 W kg -1 . Meanwhile, even when the power density was increased to 5 kW kg -1 , the energy density can still maintain 27.5 Wh kg -1 . Moreover, the LIC displayed a high capacitance retention of 80.5% after 10000 cycles at 10 A g -1 . The outstanding electrochemical performance can be contributed to the synergistic effect of the well-dispersed ultrafine TiO 2 nanoparticles, the abundant mesoporous structure, and the conductive carbon networks.

  19. Very high order lattice perturbation theory for Wilson loops

    International Nuclear Information System (INIS)

    Horsley, R.

    2010-10-01

    We calculate perturbativeWilson loops of various sizes up to loop order n=20 at different lattice sizes for pure plaquette and tree-level improved Symanzik gauge theories using the technique of Numerical Stochastic Perturbation Theory. This allows us to investigate the behavior of the perturbative series at high orders. We observe differences in the behavior of perturbative coefficients as a function of the loop order. Up to n=20 we do not see evidence for the often assumed factorial growth of the coefficients. Based on the observed behavior we sum this series in a model with hypergeometric functions. Alternatively we estimate the series in boosted perturbation theory. Subtracting the estimated perturbative series for the average plaquette from the non-perturbative Monte Carlo result we estimate the gluon condensate. (orig.)

  20. Preparation of Silica Monoliths with Macropores and Mesopores and of High Specific Surface Area with Low Shrinkage using a Template Induced Method

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Jianyu [Shanghai Normal Univ., Shanghai (China); Lu, Yan [Shanghai Institute of Technology, Shanghai (China); Whiting, Roger [AUT Univ., Auckland (New Zealand)

    2013-02-15

    In this study we report a new method for the synthesis of a silica monolithic column bed with bimodal pores (throughpores and mesopores). The template induced synthesis method was used to direct bimodal pores simultaneously instead of the usual post base-treating method. Block polymer Pluronic F127 was chosen as a dual-function template to form hierarchically porous silica monolith with both macropores and mesopores. This is a simplification of the method of monolithic column preparation. Poly(ethylene glycol) was used as a partial substitute for F127 can effectively prevent shrinkage during the monolith aging process without losing much surface area (944 m{sup 2}/g to 807 m{sup 2}/g). More importantly, the resultant material showed a much narrower mesopore size (centered at 6 nm) distribution than that made using only F127 as the template reagent, which helps the mass transfer process. The solvent washing method was used to remove the remaining organic template, and it was proved to be effective enough. The new synthesis method makes the fabrication of the silica monolithic column (especially capillary column) much easier. All the structure parameters indicate that monolith PFA05 prepared by the above method is a good material for separation, with the merits of much higher surface area than usual commercial HPLC silica particles, suitable mesopore volume, narrow mesopore size distribution, low shrinkage and it is easily prepared.

  1. Mesoporous Transition Metal Oxides for Supercapacitors.

    Science.gov (United States)

    Wang, Yan; Guo, Jin; Wang, Tingfeng; Shao, Junfeng; Wang, Dong; Yang, Ying-Wei

    2015-10-14

    Recently, transition metal oxides, such as ruthenium oxide (RuO₂), manganese dioxide (MnO₂), nickel oxides (NiO) and cobalt oxide (Co₃O₄), have been widely investigated as electrode materials for pseudo-capacitors. In particular, these metal oxides with mesoporous structures have become very hot nanomaterials in the field of supercapacitors owing to their large specific surface areas and suitable pore size distributions. The high specific capacities of these mesoporous metal oxides are resulted from the effective contacts between electrode materials and electrolytes as well as fast transportation of ions and electrons in the bulk of electrode and at the interface of electrode and electrolyte. During the past decade, many achievements on mesoporous transition metal oxides have been made. In this mini-review, we select several typical nanomaterials, such as RuO₂, MnO₂, NiO, Co₃O₄ and nickel cobaltite (NiCo₂O₄), and briefly summarize the recent research progress of these mesoporous transition metal oxides-based electrodes in the field of supercapacitors.

  2. Mesoporous Transition Metal Oxides for Supercapacitors

    Science.gov (United States)

    Wang, Yan; Guo, Jin; Wang, Tingfeng; Shao, Junfeng; Wang, Dong; Yang, Ying-Wei

    2015-01-01

    Recently, transition metal oxides, such as ruthenium oxide (RuO2), manganese dioxide (MnO2), nickel oxides (NiO) and cobalt oxide (Co3O4), have been widely investigated as electrode materials for pseudo-capacitors. In particular, these metal oxides with mesoporous structures have become very hot nanomaterials in the field of supercapacitors owing to their large specific surface areas and suitable pore size distributions. The high specific capacities of these mesoporous metal oxides are resulted from the effective contacts between electrode materials and electrolytes as well as fast transportation of ions and electrons in the bulk of electrode and at the interface of electrode and electrolyte. During the past decade, many achievements on mesoporous transition metal oxides have been made. In this mini-review, we select several typical nanomaterials, such as RuO2, MnO2, NiO, Co3O4 and nickel cobaltite (NiCo2O4), and briefly summarize the recent research progress of these mesoporous transition metal oxides-based electrodes in the field of supercapacitors. PMID:28347088

  3. Mesoporous Transition Metal Oxides for Supercapacitors

    Directory of Open Access Journals (Sweden)

    Yan Wang

    2015-10-01

    Full Text Available Recently, transition metal oxides, such as ruthenium oxide (RuO2, manganese dioxide (MnO2, nickel oxides (NiO and cobalt oxide (Co3O4, have been widely investigated as electrode materials for pseudo-capacitors. In particular, these metal oxides with mesoporous structures have become very hot nanomaterials in the field of supercapacitors owing to their large specific surface areas and suitable pore size distributions. The high specific capacities of these mesoporous metal oxides are resulted from the effective contacts between electrode materials and electrolytes as well as fast transportation of ions and electrons in the bulk of electrode and at the interface of electrode and electrolyte. During the past decade, many achievements on mesoporous transition metal oxides have been made. In this mini-review, we select several typical nanomaterials, such as RuO2, MnO2, NiO, Co3O4 and nickel cobaltite (NiCo2O4, and briefly summarize the recent research progress of these mesoporous transition metal oxides-based electrodes in the field of supercapacitors.

  4. Biocompatibility of Soft-Templated Mesoporous Carbons

    Energy Technology Data Exchange (ETDEWEB)

    Gencoglu, Maria F. [Michigan Technological Univ., Houghton, MI (United States). Dept. of Chemical Engineering; Spurri, Amanda [Widener Univ., Chester, PA (United States). Dept. of Chemical Engineering; Franko, Mitchell [Widener Univ., Chester, PA (United States). Dept. of Chemical Engineering; Chen, Jihua [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Science (CNMS); Hensley, Dale K. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Science (CNMS); Heldt, Caryn L. [Michigan Technological Univ., Houghton, MI (United States). Dept. of Chemical Engineering; Saha, Dipendu [Widener Univ., Chester, PA (United States). Dept. of Chemical Engineering

    2014-08-21

    We report that soft-templated mesoporous carbon is morphologically a non-nano type of carbon. It is a relatively newer variety of biomaterial, which has already demonstrated its successful role in drug delivery applications. To investigate the toxicity and biocompatibility, we introduced three types of mesoporous carbons with varying synthesis conditions and pore textural properties. We compared the Brunauer–Emmett–Teller (BET) surface area and pore width and performed cytotoxicity experiments with HeLa cells, cell viability studies with fibroblast cells and hemocomapatibility studies. Cytotoxicity tests reveal that two of the carbons are not cytotoxic, with cell survival over 90%. The mesoporous carbon with the highest surface area showed slight toxicity (~70% cell survival) at the highest carbon concentration of 500 μg/mL. Fibroblast cell viability assays suggested high and constant viability of over 98% after 3 days with no apparent relation with materials property and good visible cell-carbon compatibility. No hemolysis (<1%) was confirmed for all the carbon materials. Protein adsorption experiments with bovine serum albumin (BSA) and fibrinogen revealed a lower protein binding capacity of 0.2–0.6 mg/m2 and 2–4 mg/m2 for BSA and fibrinogen, respectively, with lower binding associated with an increase in surface area. The results of this study confirm the biocompatibility of soft-templated mesoporous carbons.

  5. Improvement of the Derjaguin-Broekhoff-de Boer theory for the capillary condensation/evaporation of nitrogen in spherical cavities and its application for the pore size analysis of silicas with ordered cagelike mesopores.

    Science.gov (United States)

    Kowalczyk, Piotr; Jaroniec, Mietek; Kaneko, Katsumi; Terzyk, Artur P; Gauden, Piotr A

    2005-11-08

    In a previous work, we proposed an improvement of the Derjaguin-Broekhoff-de Boer (DBdB) theory for capillary condensation/evaporation in open-ended cylindrical mesopores. In this paper, we report a further extension of this approach to the capillary condensation/evaporation of nitrogen in siliceous spherical cavities. The main idea of this improvement is to employ the Gibbs-Tolman-Koenig-Buff equation to predict the variation of the surface tension in spherical mesopores. In addition, the statistical film thickness (the so-called t-curve), which is evaluated accurately on the basis of adsorption isotherms measured for MCM-41 materials, is used instead of the originally proposed t-curve to take into account the excess chemical potential due to the surface forces. It is shown that the aforementioned modifications of the original DBdB theory that was refined by Ravikovitch and Neimark have significant implications for the pore size analysis of cagelike mesoporous silicas. To verify the proposed improvement of the DBdB pore size analysis (IDBdB), two series of FDU-1 samples, which are well-defined cagelike mesoporous materials (composed of siliceous spherical cavities interconnected by short necks), were used for the evaluation of the pore size distributions (PSDs). The correlation between the spinodal condensation point in the spherical pores predicted by the nonlocal density functional theory (NDFT) developed by Ravikovitch and Neimark and that predicted by the IDBdB theory is very good in the whole range of mesopores. This feature is mirrored to the realistic PSD characterized by the bimodal structure of pores computed from the IDBdB theory. As in the case of open-ended cylindrical pores, the improvement of the classical DBdB theory preserves its simplicity and simultaneously ensures a significant improvement of the pore size analysis, which is confirmed by the independent estimation of the average pore size by the NDFT and the powder X-ray diffraction method.

  6. Ultrathin mesoporous Co{sub 3}O{sub 4} nanosheets-constructed hierarchical clusters as high rate capability and long life anode materials for lithium-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Shengming [Key Laboratory of Functional Inorganic Materials Chemistry, Ministry of Education, School of Chemistry, Chemical Engineering and Materials, Heilongjiang University, Heilongjiang, Harbin 150080 (China); Xia, Tian, E-mail: xiatian@hlju.edu.cn [Key Laboratory of Functional Inorganic Materials Chemistry, Ministry of Education, School of Chemistry, Chemical Engineering and Materials, Heilongjiang University, Heilongjiang, Harbin 150080 (China); Wang, Jingping [Key Laboratory of Superlight Material and Surface Technology, Ministry of Education, College of Materials Science and Chemical Engineering, Harbin Engineering University, Heilongjiang, Harbin 150001 (China); Lu, Feifei [Key Laboratory of Functional Inorganic Materials Chemistry, Ministry of Education, School of Chemistry, Chemical Engineering and Materials, Heilongjiang University, Heilongjiang, Harbin 150080 (China); Xu, Chunbo [Key Laboratory of Superlight Material and Surface Technology, Ministry of Education, College of Materials Science and Chemical Engineering, Harbin Engineering University, Heilongjiang, Harbin 150001 (China); Zhang, Xianfa; Huo, Lihua [Key Laboratory of Functional Inorganic Materials Chemistry, Ministry of Education, School of Chemistry, Chemical Engineering and Materials, Heilongjiang University, Heilongjiang, Harbin 150080 (China); Zhao, Hui, E-mail: zhaohui98@yahoo.com [Key Laboratory of Functional Inorganic Materials Chemistry, Ministry of Education, School of Chemistry, Chemical Engineering and Materials, Heilongjiang University, Heilongjiang, Harbin 150080 (China)

    2017-06-01

    Graphical abstract: Ultrathin mesoporous Co{sub 3}O{sub 4} nanosheets-constructed hierarchical clusters (UMCN-HCs) have been successfully synthesized via a facile hydrothermal method followed by a subsequent thermolysis treatment. When tested as anode materials for LIBs, UMCN-HCs achieve high reversible capacity, good long cycling life, and rate capability. - Highlights: • UMCN-HCs show high capacity, excellent stability, and good rate capability. • UMCN-HCs retain a capacity of 1067 mAh g{sup −1} after 100 cycles at 100 mA g{sup −1}. • UMCN-HCs deliver a capacity of 507 mAh g{sup −1} after 500 cycles at 2 A g{sup −1}. - Abstract: Herein, Ultrathin mesoporous Co{sub 3}O{sub 4} nanosheets-constructed hierarchical clusters (UMCN-HCs) have been successfully synthesized via a facile hydrothermal method followed by a subsequent thermolysis treatment at 600 °C in air. The products consist of cluster-like Co{sub 3}O{sub 4} microarchitectures, which are assembled by numerous ultrathin mesoporous Co{sub 3}O{sub 4} nanosheets. When tested as anode materials for lithium-ion batteries, UMCN-HCs deliver a high reversible capacity of 1067 mAh g{sup −1} at a current density of 100 mA g{sup −1} after 100 cycles. Even at 2 A g{sup −1}, a stable capacity as high as 507 mAh g{sup −1} can be achieved after 500 cycles. The high reversible capacity, excellent cycling stability, and good rate capability of UMCN-HCs may be attributed to their mesoporous sheet-like nanostructure. The sheet-layered structure of UMCN-HCs may buffer the volume change during the lithiation-delithiation process, and the mesoporous characteristic make lithium-ion transfer more easily at the interface between the active electrode and the electrolyte.

  7. High-Order Modulation for Optical Fiber Transmission

    CERN Document Server

    Seimetz, Matthias

    2009-01-01

    Catering to the current interest in increasing the spectral efficiency of optical fiber networks by the deployment of high-order modulation formats, this monograph describes transmitters, receivers and performance of optical systems with high-order phase and quadrature amplitude modulation. In the first part of the book, the author discusses various transmitter implementation options as well as several receiver concepts based on direct and coherent detection, including designs of new structures. Hereby, both optical and electrical parts are considered, allowing the assessment of practicability and complexity. In the second part, a detailed characterization of optical fiber transmission systems is presented, regarding a wide range of modulation formats. It provides insight in the fundamental behavior of different formats with respect to relevant performance degradation effects and identifies the major trends in system performance.

  8. High-order harmonic generation in laser plasma plumes

    CERN Document Server

    Ganeev, Rashid A

    2013-01-01

    This book represents the first comprehensive treatment of high-order harmonic generation in laser-produced plumes, covering the principles, past and present experimental status and important applications. It shows how this method of frequency conversion of laser radiation towards the extreme ultraviolet range matured over the course of multiple studies and demonstrated new approaches in the generation of strong coherent short-wavelength radiation for various applications. Significant discoveries and pioneering contributions of researchers in this field carried out in various laser scientific centers worldwide are included in this first attempt to describe the important findings in this area of nonlinear spectroscopy. "High-Order Harmonic Generation in Laser Plasma Plumes" is a self-contained and unified review of the most recent achievements in the field, such as the application of clusters (fullerenes, nanoparticles, nanotubes) for efficient harmonic generation of ultrashort laser pulses in cluster-containin...

  9. Optimal explicit strong stability preserving Runge–Kutta methods with high linear order and optimal nonlinear order

    KAUST Repository

    Gottlieb, Sigal; Grant, Zachary; Higgs, Daniel

    2015-01-01

    High order spatial discretizations with monotonicity properties are often desirable for the solution of hyperbolic PDEs. These methods can advantageously be coupled with high order strong stability preserving time discretizations. The search

  10. Discrete nonlinear Schrodinger equations with arbitrarily high-order nonlinearities

    DEFF Research Database (Denmark)

    Khare, A.; Rasmussen, Kim Ø; Salerno, M.

    2006-01-01

    -Ladik equation. As a common property, these equations possess three kinds of exact analytical stationary solutions for which the Peierls-Nabarro barrier is zero. Several properties of these solutions, including stability, discrete breathers, and moving solutions, are investigated.......A class of discrete nonlinear Schrodinger equations with arbitrarily high-order nonlinearities is introduced. These equations are derived from the same Hamiltonian using different Poisson brackets and include as particular cases the saturable discrete nonlinear Schrodinger equation and the Ablowitz...

  11. High order modes in Project-X linac

    Energy Technology Data Exchange (ETDEWEB)

    Sukhanov, A., E-mail: ais@fnal.gov; Lunin, A.; Yakovlev, V.; Awida, M.; Champion, M.; Ginsburg, C.; Gonin, I.; Grimm, C.; Khabiboulline, T.; Nicol, T.; Orlov, Yu.; Saini, A.; Sergatskov, D.; Solyak, N.; Vostrikov, A.

    2014-01-11

    Project-X, a multi-MW proton source, is now under development at Fermilab. In this paper we present study of high order modes (HOM) excited in continues-wave (CW) superconducting linac of Project-X. We investigate effects of cryogenic losses caused by HOMs and influence of HOMs on beam dynamics. We find that these effects are small. We conclude that HOM couplers/dampers are not needed in the Project-X SC RF cavities.

  12. Conditional High-Order Boltzmann Machines for Supervised Relation Learning.

    Science.gov (United States)

    Huang, Yan; Wang, Wei; Wang, Liang; Tan, Tieniu

    2017-09-01

    Relation learning is a fundamental problem in many vision tasks. Recently, high-order Boltzmann machine and its variants have shown their great potentials in learning various types of data relation in a range of tasks. But most of these models are learned in an unsupervised way, i.e., without using relation class labels, which are not very discriminative for some challenging tasks, e.g., face verification. In this paper, with the goal to perform supervised relation learning, we introduce relation class labels into conventional high-order multiplicative interactions with pairwise input samples, and propose a conditional high-order Boltzmann Machine (CHBM), which can learn to classify the data relation in a binary classification way. To be able to deal with more complex data relation, we develop two improved variants of CHBM: 1) latent CHBM, which jointly performs relation feature learning and classification, by using a set of latent variables to block the pathway from pairwise input samples to output relation labels and 2) gated CHBM, which untangles factors of variation in data relation, by exploiting a set of latent variables to multiplicatively gate the classification of CHBM. To reduce the large number of model parameters generated by the multiplicative interactions, we approximately factorize high-order parameter tensors into multiple matrices. Then, we develop efficient supervised learning algorithms, by first pretraining the models using joint likelihood to provide good parameter initialization, and then finetuning them using conditional likelihood to enhance the discriminant ability. We apply the proposed models to a series of tasks including invariant recognition, face verification, and action similarity labeling. Experimental results demonstrate that by exploiting supervised relation labels, our models can greatly improve the performance.

  13. High order spectral difference lattice Boltzmann method for incompressible hydrodynamics

    Science.gov (United States)

    Li, Weidong

    2017-09-01

    This work presents a lattice Boltzmann equation (LBE) based high order spectral difference method for incompressible flows. In the present method, the spectral difference (SD) method is adopted to discretize the convection and collision term of the LBE to obtain high order (≥3) accuracy. Because the SD scheme represents the solution as cell local polynomials and the solution polynomials have good tensor-product property, the present spectral difference lattice Boltzmann method (SD-LBM) can be implemented on arbitrary unstructured quadrilateral meshes for effective and efficient treatment of complex geometries. Thanks to only first oder PDEs involved in the LBE, no special techniques, such as hybridizable discontinuous Galerkin method (HDG), local discontinuous Galerkin method (LDG) and so on, are needed to discrete diffusion term, and thus, it simplifies the algorithm and implementation of the high order spectral difference method for simulating viscous flows. The proposed SD-LBM is validated with four incompressible flow benchmarks in two-dimensions: (a) the Poiseuille flow driven by a constant body force; (b) the lid-driven cavity flow without singularity at the two top corners-Burggraf flow; and (c) the unsteady Taylor-Green vortex flow; (d) the Blasius boundary-layer flow past a flat plate. Computational results are compared with analytical solutions of these cases and convergence studies of these cases are also given. The designed accuracy of the proposed SD-LBM is clearly verified.

  14. Novel chiral core-shell silica microspheres with trans-(1R,2R)-diaminocyclohexane bridged in the mesoporous shell: synthesis, characterization and application in high performance liquid chromatography.

    Science.gov (United States)

    Wu, Xiabing; You, Linjun; Di, Bin; Hao, Weiqiang; Su, Mengxiang; Gu, Yu; Shen, Lingling

    2013-07-19

    Novel chiral core-shell silica microspheres with trans-(1R,2R)-diaminocyclohexane (DACH) moiety bridged in the mesoporous shell were synthesized using layer-by-layer method. The chiral mesoporous shell around the nonporous silica core was formed by the co-condensation of N,N'-bis-[(triethoxysilyl)propyl]-trans-(1R,2R)-bis-(ureido)-cyclohexane (DACH-BS) and tetraethoxysilane (TEOS) using octadecyltrimethylammonium chloride (C18TMACl) and triblock poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide) copolymer (P123) as the templates. The functionalized core-shell silica microspheres were characterized and tested as chiral stationary phases for high performance liquid chromatography (HPLC). R/S-1,1'-bi-2,2'-naphthol, R/S-6,6'-dibromo-1,1'-bi-2-naphthol and R/S-1,1'-bi-2,2'-phenanthrol were enantioseparated rapidly on the column packed with the DACH core-shell silica particles. Moreover, the column packed with core-shell particles exhibited better performance than the column packed with the DACH functionalized periodic mesoporous organosilicas. Copyright © 2013 Elsevier B.V. All rights reserved.

  15. High-order harmonic conversion efficiency in helium

    International Nuclear Information System (INIS)

    Crane, J.K.

    1992-01-01

    Calculated results are presented for the energy, number of photons, and conversion efficiency for high-order harmonic generation in helium. The results show the maximum values that we should expect to achieve experimentally with our current apparatus and the important parameters for scaling this source to higher output. In the desired operating regime where the coherence length, given by L coh =πb/(q-1), is greater than the gas column length, l, the harmonic output can be summarized by a single equation: N q =[(π z n z b 3 τ q |d q | z )/4h]{(p/q)(2l/b) z }. N q - numbers of photons of q-th harmonic; n - atom density; b - laser confocal parameter; τ q - pulse width of harmonic radiation; q - harmonic order; p - effective order of nonlinearity. (Note the term in brackets, the phase-matching function, has been separated from the rest of the expression in order to be consistent with the relevant literature)

  16. Mesopore- and Macropore-Dominant Nitrogen-Doped Hierarchically Porous Carbons for High-Energy and Ultrafast Supercapacitors in Non-Aqueous Electrolytes.

    Science.gov (United States)

    Shao, Rong; Niu, Jin; Liang, Jingjing; Liu, Mengyue; Zhang, Zhengping; Dou, Meiling; Huang, Yaqin; Wang, Feng

    2017-12-13

    Non-aqueous electrolytes (e.g., organic and ionic liquid electrolytes) can undergo high working voltage to improve the energy densities of supercapacitors. However, the large ion sizes, high viscosities, and low ionic conductivities of organic and ionic liquid electrolytes tend to cause the low specific capacitances, poor rate, and cycling performance of supercapacitors based on conventional micropore-dominant activated carbon electrodes, limiting their practical applications. Herein, we propose an effective strategy to simultaneously obtain high power and energy densities in non-aqueous electrolytes via using a cattle bone-derived porous carbon as an electrode material. Because of the unique co-activation of KOH and hydroxyapatite (HA) within the cattle bone, nitrogen-doped hierarchically porous carbon (referred to as NHPC-HA/KOH) is obtained and possesses a mesopore- and macropore-dominant porosity with an ultrahigh specific surface area (2203 m 2 g -1 ) of meso- and macropores. The NHPC-HA/KOH electrodes exhibit superior performance with specific capacitances of 224 and 240 F g -1 at 5 A g -1 in 1.0 M TEABF 4 /AN and neat EMIMBF 4 electrolyte, respectively. The symmetric supercapacitor using NHPC-HA/KOH electrodes can deliver integrated high energy and power properties (48.6 W h kg -1 at 3.13 kW kg -1 in 1.0 M TEABF 4 /AN and 75 W h kg -1 at 3.75 kW kg -1 in neat EMIMBF 4 ), as well as superior cycling performance (over 89% of the initial capacitance after 10 000 cycles at 10 A g -1 ).

  17. Removal of malachite green dye from aqueous solution using mesoporous silica synthesized from 1-octyl-3-methylimidazolium chloride ionic liquid

    International Nuclear Information System (INIS)

    Ekka, Basanti; Nayak, Soumitra Ranjan; Dash, Priyabrat; Patel, Raj Kishore

    2016-01-01

    In this research, mesoporous silica was synthesized via a modified sol-gel route using 1-octyl-3-methylimidazolium chloride and was employed to remove malachite green (MG) dye from aqueous solution. Subsequently, this material was characterized and identified by different techniques such as Fourier transform infrared spectroscopy (FT-IR), N_2 adsorption-desorption method, scanning electron microscopy (SEM), and thermosgravimetric analysis (TGA). Unique properties such as high surface area and pore diameter, in addition to highly reactive atoms and presence of various functional groups make the mesoporous silica possible for efficient removal of malachite green (MG). In batch experimental set-up, optimum conditions for quantitative removal of MG by mesoporous silica was attained by varying different variables such as adsorbent dosage, initial dye concentration, contact time, and pH. Optimum values were set as pH of 8.0, 0.5 g of adsorbent at contact time of 120 min. The adsorption of MG follows the pseudo-second-order rate equation. Equilibrium data fitted well with the Freundlich model at all amount of adsorbent, while maximum adsorption capacity was 5.981 mg g"−1 for 0.5 g mesoporous silica synthesized in IL.

  18. Direct synthesis of graphitic mesoporous carbon from green phenolic resins exposed to subsequent UV and IR laser irradiations

    Science.gov (United States)

    Sopronyi, Mihai; Sima, Felix; Vaulot, Cyril; Delmotte, Luc; Bahouka, Armel; Matei Ghimbeu, Camelia

    2016-01-01

    The design of mesoporous carbon materials with controlled textural and structural features by rapid, cost-effective and eco-friendly means is highly demanded for many fields of applications. We report herein on the fast and tailored synthesis of mesoporous carbon by UV and IR laser assisted irradiations of a solution consisting of green phenolic resins and surfactant agent. By tailoring the UV laser parameters such as energy, pulse repetition rate or exposure time carbon materials with different pore size, architecture and wall thickness were obtained. By increasing irradiation dose, the mesopore size diminishes in the favor of wall thickness while the morphology shifts from worm-like to an ordered hexagonal one. This was related to the intensification of phenolic resin cross-linking which induces the reduction of H-bonding with the template as highlighted by 13C and 1H NMR. In addition, mesoporous carbon with graphitic structure was obtained by IR laser irradiation at room temperature and in very short time periods compared to the classical long thermal treatment at very high temperatures. Therefore, the carbon texture and structure can be tuned only by playing with laser parameters, without extra chemicals, as usually required. PMID:28000781

  19. Adsorptive removal of selected pharmaceuticals by mesoporous silica SBA-15

    International Nuclear Information System (INIS)

    Bui, Tung Xuan; Choi, Heechul

    2009-01-01

    The removal of five selected pharmaceuticals, viz., carbamazepine, clofibric acid, diclofenac, ibuprofen, and ketoprofen was examined by batch sorption experiments onto a synthesized mesoporous silica SBA-15. SBA-15 was synthesized and characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), N 2 adsorption-desorption measurement, and point of zero charge (PZC) measurement. Pharmaceutical adsorption kinetics was rapid and occurred on a scale of minutes, following a pseudo-second-order rate expression. Adsorption isotherms were best fitted by the Freundlich isotherm model. High removal rates of individual pharmaceuticals were achieved in acidic media (pH 3-5) and reached 85.2% for carbamazepine, 88.3% for diclofenac, 93.0% for ibuprofen, 94.3% for ketoprofen, and 49.0% for clofibric acid at pH 3 but decreased with increase in pH. SBA-15 also showed high efficiency for removal of a mixture of 5 pharmaceuticals. Except for clofibric acid (35.6%), the removal of pharmaceuticals in the mixture ranged from 75.2 to 89.3%. Based on adsorption and desorption results, the mechanism of the selected pharmaceuticals was found to be a hydrophilic interaction, providing valuable information for further studies to design materials for the purpose. The results of this study suggest that mesoporous-silica-based materials are promising adsorbents for removing pharmaceuticals from not only surface water but also wastewater of pharmaceutical industrial manufactures.

  20. Adsorptive removal of selected pharmaceuticals by mesoporous silica SBA-15

    Energy Technology Data Exchange (ETDEWEB)

    Bui, Tung Xuan, E-mail: bxtung@gist.ac.kr [Department of Environmental Science and Engineering, Gwangju Institute of Science and Technology (GIST), 261 Cheomdan-gwagiro, Buk-gu, Gwangju 500-712 (Korea, Republic of); Choi, Heechul, E-mail: hcchoi@gist.ac.kr [Department of Environmental Science and Engineering, Gwangju Institute of Science and Technology (GIST), 261 Cheomdan-gwagiro, Buk-gu, Gwangju 500-712 (Korea, Republic of)

    2009-09-15

    The removal of five selected pharmaceuticals, viz., carbamazepine, clofibric acid, diclofenac, ibuprofen, and ketoprofen was examined by batch sorption experiments onto a synthesized mesoporous silica SBA-15. SBA-15 was synthesized and characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), N{sub 2} adsorption-desorption measurement, and point of zero charge (PZC) measurement. Pharmaceutical adsorption kinetics was rapid and occurred on a scale of minutes, following a pseudo-second-order rate expression. Adsorption isotherms were best fitted by the Freundlich isotherm model. High removal rates of individual pharmaceuticals were achieved in acidic media (pH 3-5) and reached 85.2% for carbamazepine, 88.3% for diclofenac, 93.0% for ibuprofen, 94.3% for ketoprofen, and 49.0% for clofibric acid at pH 3 but decreased with increase in pH. SBA-15 also showed high efficiency for removal of a mixture of 5 pharmaceuticals. Except for clofibric acid (35.6%), the removal of pharmaceuticals in the mixture ranged from 75.2 to 89.3%. Based on adsorption and desorption results, the mechanism of the selected pharmaceuticals was found to be a hydrophilic interaction, providing valuable information for further studies to design materials for the purpose. The results of this study suggest that mesoporous-silica-based materials are promising adsorbents for removing pharmaceuticals from not only surface water but also wastewater of pharmaceutical industrial manufactures.

  1. Aluminum-rich mesoporous MFI - type zeolite single crystals

    DEFF Research Database (Denmark)

    Kustova, Marina; Kustov, Arkadii; Christensen, Christina Hviid

    2005-01-01

    Zeolitcs are crystalline materials, which are widely used as solid acid catalysts and supports in many industrial processes. Recently, mesoporous MFI-type zeolite single crystals were synthesized by use of carbon particles as a mesopore template and sodium aluminate as the aluminum Source....... With this technique, only zeolites with relatively low Al contents were reported (Si/Al ratio about 100). In this work, the preparation of aluminum-rich mesoporous MFI-type zeolite single crystals (Si/Al similar to 16-50) using aluminum isopropoxide as the aluminum Source is reported for the first time. All samples...... are characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), ammonia temperature programmed desorption (NH3-TPD), and N-2 adsorption measurements. The obtained zeolites combine the high crystallinity and the characteristic micropores of zeolites with an intracrystalline mesopore system...

  2. Wilson loops in very high order lattice perturbation theory

    International Nuclear Information System (INIS)

    Ilgenfritz, E.M.; Nakamura, Y.; Perlt, H.; Schiller, A.; Rakow, P.E.L.; Schierholz, G.; Regensburg Univ.

    2009-10-01

    We calculate Wilson loops of various sizes up to loop order n=20 for lattice sizes of L 4 (L=4,6,8,12) using the technique of Numerical Stochastic Perturbation Theory in quenched QCD. This allows to investigate the behaviour of the perturbative series at high orders. We discuss three models to estimate the perturbative series: a renormalon inspired fit, a heuristic fit based on an assumed power-law singularity and boosted perturbation theory. We have found differences in the behavior of the perturbative series for smaller and larger Wilson loops at moderate n. A factorial growth of the coefficients could not be confirmed up to n=20. From Monte Carlo measured plaquette data and our perturbative result we estimate a value of the gluon condensate left angle (α)/(π)GG right angle. (orig.)

  3. A high-order SPH method by introducing inverse kernels

    Directory of Open Access Journals (Sweden)

    Le Fang

    2017-02-01

    Full Text Available The smoothed particle hydrodynamics (SPH method is usually expected to be an efficient numerical tool for calculating the fluid-structure interactions in compressors; however, an endogenetic restriction is the problem of low-order consistency. A high-order SPH method by introducing inverse kernels, which is quite easy to be implemented but efficient, is proposed for solving this restriction. The basic inverse method and the special treatment near boundary are introduced with also the discussion of the combination of the Least-Square (LS and Moving-Least-Square (MLS methods. Then detailed analysis in spectral space is presented for people to better understand this method. Finally we show three test examples to verify the method behavior.

  4. Selective Preparation of trans-Carveol over Ceria Supported Mesoporous Materials MCM-41 and SBA-15

    Directory of Open Access Journals (Sweden)

    Nariman F. Salakhutdinov

    2013-05-01

    Full Text Available Ce-modified mesoporous silica materials MCM-41 and SBA-15, namely 32 wt % Ce–Si–MCM-41, 16 wt % Ce–H–MCM-41 and 20 wt % Ce–Si–SBA-15, were prepared, characterized and studied in the selective preparation of trans-carveol by α-pinene oxide isomerization. The characterizations of these catalysts were performed using scanning electron microscopy, X-ray photoelectron spectroscopy, nitrogen adsorption and FTIR pyridine adsorption. Selective preparation of trans-carveol was carried out in the liquid phase in a batch reactor. The activity and the selectivity of catalyst were observed to be influenced by their acidity, basicity and morphology of the mesoporous materials. The formation of trans-carveol is moreover strongly influenced by the basicity of the used solvent and in order to achieve high yields of this desired alcohol it is necessary to use polar basic solvent.

  5. Hemi-ordered nanoporous carbon electrode material for highly selective determination of nitrite in physiological and environmental systems

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Shenghai; Wu, Hongmin; Wu, Ying; Shi, Hongyan; Feng, Xun; Jiang, Shang; Chen, Jian; Song, Wenbo, E-mail: wbsong@jlu.edu.cn

    2014-08-01

    Hemi-ordered nanoporous carbon (HONC) was obtained from a mesoporous silica template through a nano-replication method using furfuryl alcohol as the carbon source. The structure and morphology of HONC were characterized and analyzed in detail by X-ray diffraction, N{sub 2}-sorption, Raman spectroscopy and transmission electron microscopy. HONC was then demonstrated as active electrode material for selective determination of nitrite in either physiological or environmental system. Well separated oxidation peaks of ascorbic acid, dopamine, uric acid and nitrite were observed in physiological system, and simultaneous discrimination of catechol, hydroquinone, resorcinol and nitrite in environmental system was also accomplished. Distinctly improved performances for selective determination of nitrite (such as significantly fast and sensitive current response with especially high selectivity) coexisted with ascorbic acid, dopamine and uric acid in the physiological system, as well as with catechol, hydroquinone and resorcinol in the environmental system were achieved at HONC electrode material. The excellent discriminating ability and high selectivity for NO{sub 2}{sup −} determination were ascribed to the good electronic conductivity, unique hemi-ordered porous structure, large surface area and large number of edge plane defect sites contained on the surface of nanopore walls of HONC. Results in this work demonstrated that HONC is one of the promising catalytic electrode materials for nitrite sensor fabrication. - Highlights: • Hemi-ordered nanoporous carbon as an active electrode material • Good discriminating ability towards NO{sub 2}{sup −} from physiological or environmental system • Highly selective determination of nitrite with fast and sensitive current response.

  6. Mesoporous Nb and Ta Oxides: Synthesis, Characterization and Applications in Heterogeneous Acid Catalysis

    Science.gov (United States)

    Rao, Yuxiang Tony

    In this work, a series of mesoporous Niobium and Tantalum oxides with different pore sizes (C6, C12, C18 , ranging from 12A to 30 A) were synthesized using the ligand-assisted templating approach and investigated for their activities in a wide range of catalytic applications including benzylation, alkylation and isomerization. The as-synthesized mesoporous materials were characterized by nitrogen adsorption, powder X-ray diffraction, transmission electron microscopy (TEM), scanning electron microscopy (SEM), thermo gravimetric analysis (TGA), differential scanning calorimetry (DSC), and solid-state Nuclear magnetic resonance (NMR) techniques. In order to probe into the structural and coordination geometry of mesoporous Nb oxide and in efforts to make meaningful comparisons of mesoporous niobia prepared by the amine-templating method with the corresponding bulk sol-gel prepared Nb2O5 phase, 17O magic-angle-spinning solid-state NMR studies were conducted. The results showed a very high local order in the mesoporous sample. The oxygen atoms are coordinated only as ONb 2 in contrast with bulk phases in which the oxygen atoms are always present in a mixture of ONb2 and ONb3 coordination environments. To enhance their surface acidities and thus improve their performance as solid acid catalysts in the acid-catalyzed reactions mentioned above, pure mesoporous Nb and Ta oxides were further treated with 1M sulfuric acid or phosphoric acid. Their surface acidities before and after acid treatment were measured by Fourier transform infraRed (FT IR), amine titration and temperature programmed desorption of ammonia (NH3-TPD). Results obtained in this study showed that sulfated mesoporous Nb and Ta oxides materials possess relative high surface areas (up to 612 m 2/g) and amorphous wormhole structure. These mesoporous structures are thus quite stable to acid treatment. It was also found that Bronsted (1540 cm-1) and Lewis (1450 cm-1) acid sites coexist in a roughly 50:50 mixture

  7. FePO4 nanoparticles embedded in a large mesoporous carbon matrix as a high-capacity and high-rate cathode for lithium-ion batteries

    International Nuclear Information System (INIS)

    Chen, Lian; Wu, Ping; Xie, Kongwei; Li, Jianping; Xu, Bin; Cao, Gaoping; Chen, Yu; Tang, Yawen; Zhou, Yiming; Lu, Tianhong; Yang, Yusheng

    2013-01-01

    Highlights: ► Self-made nano-CaCO 3 templated LMC as a novel supporting matrix for FePO 4 cathode. ► The 3D porous structure of LMC is well retained in LMC–FePO 4 nanohybrid. ► Its reaction kinetics of lithium insertion/extraction is significantly improved. ► Markedly higher capacities and rate capability by virtue of its structure superiority. -- Abstract: By using large mesoporous carbon (LMC) as a novel host matrix, LMC–FePO 4 nanohybrid has been synthesized through a facile homogeneous precipitation process and subsequent annealing approach. When evaluated as a cathode for lithium-ion batteries (LIBs), the LMC–FePO 4 nanohybrid exhibits higher specific capacities, improved rate capability, and better cycling performance by virtue of its unique structural characteristics

  8. Nature-Inspired 2D-Mosaic 3D-Gradient Mesoporous Framework: Bimetal Oxide Dual-Composite Strategy toward Ultrastable and High-Capacity Lithium Storage.

    Science.gov (United States)

    Yu, Jia; Wang, Yanlei; Mou, Lihui; Fang, Daliang; Chen, Shimou; Zhang, Suojiang

    2018-02-27

    In allusion to traditional transition-metal oxide (TMO) anodes for lithium-ion batteries, which face severe volume variation and poor conductivity, herein a bimetal oxide dual-composite strategy based on two-dimensional (2D)-mosaic three-dimensional (3D)-gradient design is proposed. Inspired by natural mosaic dominance phenomena, Zn 1-x Co x O/ZnCo 2 O 4 2D-mosaic-hybrid mesoporous ultrathin nanosheets serve as building blocks to assemble into a 3D Zn-Co hierarchical framework. Moreover, a series of derivative frameworks with high evolution are controllably synthesized, based on which a facile one-pot synthesis process can be developed. From a component-composite perspective, both Zn 1-x Co x O and ZnCo 2 O 4 provide superior conductivity due to bimetal doping effect, which is verified by density functional theory calculations. From a structure-composite perspective, 2D-mosaic-hybrid mode gives rise to ladder-type buffering and electrochemical synergistic effect, thus realizing mutual stabilization and activation between the mosaic pair, especially for Zn 1-x Co x O with higher capacity yet higher expansion. Moreover, the inside-out Zn-Co concentration gradient in 3D framework and rich oxygen vacancies further greatly enhance Li storage capability and stability. As a result, a high reversible capacity (1010 mA h g -1 ) and areal capacity (1.48 mA h cm -2 ) are attained, while ultrastable cyclability is obtained during high-rate and long-term cycles, rending great potential of our 2D-mosaic 3D-gradient design together with facile synthesis.

  9. High-order harmonics generation from overdense plasmas

    International Nuclear Information System (INIS)

    Quere, F.; Thaury, C.; Monot, P.; Martin, Ph.; Geindre, J.P.; Audebert, P.; Marjoribanks, R.

    2006-01-01

    Complete test of publication follows. When an intense laser beam reflects on an overdense plasma generated on a solid target, high-order harmonics of the incident laser frequency are observed in the reflected beam. This process provides a way to produce XUV femtosecond and attosecond pulses in the μJ range from ultrafast ultraintense lasers. Studying the mechanisms responsible for this harmonic emission is also of strong fundamental interest: just as HHG in gases has been instrumental in providing a comprehensive understanding of basic intense laser-atom interactions, HHG from solid-density plasmas is likely to become a unique tool to investigate many key features of laser-plasma interactions at high intensities. We will present both experimental and theoretical evidence that two mechanisms contribute to this harmonic emission: - Coherent Wake Emission: in this process, harmonics are emitted by plasma oscillations in te overdense plasma, triggered in the wake of jets of Brunel electrons generated by the laser field. - The relativistic oscillating mirror: in this process, the intense laser field drives a relativistic oscillation of the plasma surface, which in turn gives rise to a periodic phase modulation of the reflected beam, and hence to the generation of harmonics of the incident frequency. Left graph: experimental harmonic spectrum from a polypropylene target, obtained with 60 fs laser pulses at 10 19 W/cm 2 , with a very high temporal contrast (10 10 ). The plasma frequency of this target corresponds to harmonics 15-16, thus excluding the CWE mechanism for the generation of harmonics of higher orders. Images on the right: harmonic spectra from orders 13 et 18, for different distances z between the target and the best focus. At the highest intensity (z=0), harmonics emitted by the ROM mechanism are observed above the 15th order. These harmonics have a much smaller spectral width then those due to CWE (below the 15th order). These ROM harmonics vanish as soon

  10. Hybrid overlay metrology for high order correction by using CDSEM

    Science.gov (United States)

    Leray, Philippe; Halder, Sandip; Lorusso, Gian; Baudemprez, Bart; Inoue, Osamu; Okagawa, Yutaka

    2016-03-01

    Overlay control has become one of the most critical issues for semiconductor manufacturing. Advanced lithographic scanners use high-order corrections or correction per exposure to reduce the residual overlay. It is not enough in traditional feedback of overlay measurement by using ADI wafer because overlay error depends on other process (etching process and film stress, etc.). It needs high accuracy overlay measurement by using AEI wafer. WIS (Wafer Induced Shift) is the main issue for optical overlay, IBO (Image Based Overlay) and DBO (Diffraction Based Overlay). We design dedicated SEM overlay targets for dual damascene process of N10 by i-ArF multi-patterning. The pattern is same as device-pattern locally. Optical overlay tools select segmented pattern to reduce the WIS. However segmentation has limit, especially the via-pattern, for keeping the sensitivity and accuracy. We evaluate difference between the viapattern and relaxed pitch gratings which are similar to optical overlay target at AEI. CDSEM can estimate asymmetry property of target from image of pattern edge. CDSEM can estimate asymmetry property of target from image of pattern edge. We will compare full map of SEM overlay to full map of optical overlay for high order correction ( correctables and residual fingerprints).

  11. High-order space charge effects using automatic differentiation

    International Nuclear Information System (INIS)

    Reusch, Michael F.; Bruhwiler, David L.

    1997-01-01

    The Northrop Grumman Topkark code has been upgraded to Fortran 90, making use of operator overloading, so the same code can be used to either track an array of particles or construct a Taylor map representation of the accelerator lattice. We review beam optics and beam dynamics simulations conducted with TOPKARK in the past and we present a new method for modeling space charge forces to high-order with automatic differentiation. This method generates an accurate, high-order, 6-D Taylor map of the phase space variable trajectories for a bunched, high-current beam. The spatial distribution is modeled as the product of a Taylor Series times a Gaussian. The variables in the argument of the Gaussian are normalized to the respective second moments of the distribution. This form allows for accurate representation of a wide range of realistic distributions, including any asymmetries, and allows for rapid calculation of the space charge fields with free space boundary conditions. An example problem is presented to illustrate our approach

  12. High-order space charge effects using automatic differentiation

    International Nuclear Information System (INIS)

    Reusch, M.F.; Bruhwiler, D.L.; Computer Accelerator Physics Conference Williamsburg, Virginia 1996)

    1997-01-01

    The Northrop Grumman Topkark code has been upgraded to Fortran 90, making use of operator overloading, so the same code can be used to either track an array of particles or construct a Taylor map representation of the accelerator lattice. We review beam optics and beam dynamics simulations conducted with TOPKARK in the past and we present a new method for modeling space charge forces to high-order with automatic differentiation. This method generates an accurate, high-order, 6-D Taylor map of the phase space variable trajectories for a bunched, high-current beam. The spatial distribution is modeled as the product of a Taylor Series times a Gaussian. The variables in the argument of the Gaussian are normalized to the respective second moments of the distribution. This form allows for accurate representation of a wide range of realistic distributions, including any asymmetries, and allows for rapid calculation of the space charge fields with free space boundary conditions. An example problem is presented to illustrate our approach. copyright 1997 American Institute of Physics

  13. High-order harmonic generation in a capillary discharge

    Science.gov (United States)

    Rocca, Jorge J.; Kapteyn, Henry C.; Mumane, Margaret M.; Gaudiosi, David; Grisham, Michael E.; Popmintchev, Tenio V.; Reagan, Brendan A.

    2010-06-01

    A pre-ionized medium created by a capillary discharge results in more efficient use of laser energy in high-order harmonic generation (HHG) from ions. It extends the cutoff photon energy, and reduces the distortion of the laser pulse as it propagates down the waveguide. The observed enhancements result from a combination of reduced ionization energy loss and reduced ionization-induced defocusing of the driving laser as well as waveguiding of the driving laser pulse. The discharge plasma also provides a means to spectrally tune the harmonics by tailoring the initial level of ionization of the medium.

  14. Stability of the high-order finite elements for acoustic or elastic wave propagation with high-order time stepping

    KAUST Repository

    De Basabe, Jonás D.

    2010-04-01

    We investigate the stability of some high-order finite element methods, namely the spectral element method and the interior-penalty discontinuous Galerkin method (IP-DGM), for acoustic or elastic wave propagation that have become increasingly popular in the recent past. We consider the Lax-Wendroff method (LWM) for time stepping and show that it allows for a larger time step than the classical leap-frog finite difference method, with higher-order accuracy. In particular the fourth-order LWM allows for a time step 73 per cent larger than that of the leap-frog method; the computational cost is approximately double per time step, but the larger time step partially compensates for this additional cost. Necessary, but not sufficient, stability conditions are given for the mentioned methods for orders up to 10 in space and time. The stability conditions for IP-DGM are approximately 20 and 60 per cent more restrictive than those for SEM in the acoustic and elastic cases, respectively. © 2010 The Authors Journal compilation © 2010 RAS.

  15. High order effects in cross section sensitivity analysis

    International Nuclear Information System (INIS)

    Greenspan, E.; Karni, Y.; Gilai, D.

    1978-01-01

    Two types of high order effects associated with perturbations in the flux shape are considered: Spectral Fine Structure Effects (SFSE) and non-linearity between changes in performance parameters and data uncertainties. SFSE are investigated in Part I using a simple single resonance model. Results obtained for each of the resolved and for representative unresolved resonances of 238 U in a ZPR-6/7 like environment indicate that SFSE can have a significant contribution to the sensitivity of group constants to resonance parameters. Methods to account for SFSE both for the propagation of uncertainties and for the adjustment of nuclear data are discussed. A Second Order Sensitivity Theory (SOST) is presented, and its accuracy relative to that of the first order sensitivity theory and of the direct substitution method is investigated in Part II. The investigation is done for the non-linear problem of the effect of changes in the 297 keV sodium minimum cross section on the transport of neutrons in a deep-penetration problem. It is found that the SOST provides a satisfactory accuracy for cross section uncertainty analysis. For the same degree of accuracy, the SOST can be significantly more efficient than the direct substitution method

  16. Design and high order optimization of the ATF2 lattices

    CERN Document Server

    Marin, E; Woodley, M; Kubo, K; Okugi, T; Tauchi, T; Urakawa, J; Tomas, R

    2013-01-01

    The next generation of future linear colliders (LC) demands nano-meter beam sizes at the interaction point (IP) in order to reach the required luminosity. The final focus system (FFS) of a LC is meant to deliver such small beam sizes. The Accelerator Test Facility (ATF) aims to test the feasibility of the new local chromaticity correction scheme which the future LCs are based on. To this end the ATF2 nominal and ultra-low beta* lattices are design to vertically focus the beam at the IP to 37nm and 23nm, respectively if error-free lattices are considered. However simulations show that the measured field errors of the ATF2 magnets preclude to reach the mentioned spot sizes. This paper describes the optimization of high order aberrations of the ATF2 lattices in order to minimize the detrimental effect of the measured multipole components for both ATF2 lattices. Specifically three solutions are studied, the replacement of the last focusing quadrupole (QF1FF), insertion of octupole magnets and optics modification....

  17. Optimal explicit strong stability preserving Runge–Kutta methods with high linear order and optimal nonlinear order

    KAUST Repository

    Gottlieb, Sigal

    2015-04-10

    High order spatial discretizations with monotonicity properties are often desirable for the solution of hyperbolic PDEs. These methods can advantageously be coupled with high order strong stability preserving time discretizations. The search for high order strong stability time-stepping methods with large allowable strong stability coefficient has been an active area of research over the last two decades. This research has shown that explicit SSP Runge-Kutta methods exist only up to fourth order. However, if we restrict ourselves to solving only linear autonomous problems, the order conditions simplify and this order barrier is lifted: explicit SSP Runge-Kutta methods of any linear order exist. These methods reduce to second order when applied to nonlinear problems. In the current work we aim to find explicit SSP Runge-Kutta methods with large allowable time-step, that feature high linear order and simultaneously have the optimal fourth order nonlinear order. These methods have strong stability coefficients that approach those of the linear methods as the number of stages and the linear order is increased. This work shows that when a high linear order method is desired, it may still be worthwhile to use methods with higher nonlinear order.

  18. High-order quantum algorithm for solving linear differential equations

    International Nuclear Information System (INIS)

    Berry, Dominic W

    2014-01-01

    Linear differential equations are ubiquitous in science and engineering. Quantum computers can simulate quantum systems, which are described by a restricted type of linear differential equations. Here we extend quantum simulation algorithms to general inhomogeneous sparse linear differential equations, which describe many classical physical systems. We examine the use of high-order methods (where the error over a time step is a high power of the size of the time step) to improve the efficiency. These provide scaling close to Δt 2 in the evolution time Δt. As with other algorithms of this type, the solution is encoded in amplitudes of the quantum state, and it is possible to extract global features of the solution. (paper)

  19. Synthesis and characterization of V, Mo and Nb incorporated micro-mesoporous MCM-41 materials

    Energy Technology Data Exchange (ETDEWEB)

    Solmaz, Arzu, E-mail: arzu.solmaz@rshm.gov.tr [Gazi University, Faculty of Engineering, Chemical Engineering Department, 06570 Ankara (Turkey); Balci, Suna, E-mail: sunabalci@gazi.edu.tr [Gazi University, Faculty of Engineering, Chemical Engineering Department, 06570 Ankara (Turkey); Dogu, Timur, E-mail: tdogu@metu.edu.tr [Middle East Technical University, Faculty of Engineering, Chemical Engineering Department, 06531 Ankara (Turkey)

    2011-01-01

    Highly microporous metal-MCM-41 ordered mesoporous structure catalysts having different metal/Si (V, Mo, Nb) atomic ratios and combinations of metal sources were hydrothermally synthesized. The structural properties estimated using different techniques were found to be in agreement with each other. Metals were successfully incorporated into MCM-41 without deteriorating the ordered hexagonal structure. The metal ions in the synthesis solutions probably settled on the hydrophilic end of the template hence the metal incorporation resulted improvements in the micropore structure. Low loading of metals caused an increase in the surface area and pore volume values of the catalysts. The highest total (1310 m{sup 2} g{sup -1}) and micropore surface area values (1083 m{sup 2} g{sup -1}) were obtained by Nb incorporation. The micro- and mesopore dimensions of MCM-41 increased from 0.5 to 1.1 nm and from 2.5 to 2.8 nm, respectively, with metal incorporation. Low V/Si ratios and presence of Nb in the starting solution enhanced narrow mesopore size distribution. The pore dimension and wall thickness values estimated from nitrogen adsorption and X-ray diffraction methods were consistent with the corresponding values obtained using transmission electron microscopy.

  20. Eco-Friendly Synthesis of Nitrogen-Doped Mesoporous Carbon for Supercapacitor Application

    Directory of Open Access Journals (Sweden)

    Georges Moussa

    2018-03-01

    Full Text Available A sustainable and simple synthesis procedure involving the co-assembly of green phenolic resin and amphiphilic polymer template in water/ethanol mixture at room temperature to synthesize nitrogen doped mesoporous carbon is reported herein. Guanine is proposed as a novel nitrogen-based precursor which is able to create H-bondings both with the phenolic resin and the template allowing the formation of mesoporous carbons with nitrogen atoms uniformly distributed in their framework. The influence of the synthesis procedure, template amount and annealing temperature on the carbon textural properties, structure and surface chemistry were investigated. For several conditions, carbon materials with ordered pore size and high nitrogen content (up to 10.6 at % could be achieved. The phase separation procedure combined with optimal amount of template favor the formation of ordered mesoporous carbons with higher specific surface area while the increase in the temperature induces a decrease in the surface area and amount of heteroatoms (N and O. The electrochemical performances as electrode in supercapacitors were evaluated in acidic medium and the capacitance was closely related to the material conductivity and surface chemistry.

  1. Ion-Exchange-Induced Selective Etching for the Synthesis of Amino-Functionalized Hollow Mesoporous Silica for Elevated-High-Temperature Fuel Cells.

    Science.gov (United States)

    Zhang, Jin; Liu, Jian; Lu, Shanfu; Zhu, Haijin; Aili, David; De Marco, Roland; Xiang, Yan; Forsyth, Maria; Li, Qingfeng; Jiang, San Ping

    2017-09-20

    As differentiated from conventional synthetic processes, amino-functionalized hollow mesoporous silica (NH 2 -HMS) has been synthesized using a new and facile strategy of ion-exchange-induced selective etching of amino-functionalized mesoporous silica (NH 2 -meso-silica) by an alkaline solution. Nuclear magnetic resonance (NMR) spectroscopy and in situ time-resolved small-angle X-ray scattering (SAXS) reveal that ion-exchange-induced selective etching arises from the gradient distribution of OH - in the NH 2 -meso-silica nanospheres. Moreover, the ion-exchange-induced selective etching mechanism is verified through a successful synthesis of hollow mesoporous silica. After infiltration with phosphotungstic acid (PWA), PWA-NH 2 -HMS nanoparticles are dispersed in the poly(ether sulfone)-polyvinylpyrrolidone (PES-PVP) matrix, forming a hybrid PWA-NH 2 -HMS/PES-PVP nanocomposite membrane. The resultant nanocomposite membrane with an optimum loading of 10 wt % of PWA-NH 2 -HMS showed an enhanced proton conductivity of 0.175 S cm -1 and peak power density of 420 mW cm -2 at 180 °C under anhydrous conditions. Excellent durability of the hybrid composite membrane fuel cell has been demonstrated at 200 °C. The results of this study demonstrated the potential of the facile synthetic strategy in the fabrication of NH 2 -HMS with controlled mesoporous structure for application in nanocomposite membranes as a technology platform for elevated-temperature proton exchange membrane fuel cells.

  2. Ion-Exchange-Induced Selective Etching for the Synthesis of Amino-Functionalized Hollow Mesoporous Silica for Elevated-High-Temperature Fuel Cells

    DEFF Research Database (Denmark)

    Zhang, Jin; Liu, Jian; Lu, Shanfu

    2017-01-01

    is verified through a successful synthesis of hollow mesoporous silica. After infiltration with phosphotungstic acid (PWA), PWA–NH2–HMS nanoparticles are dispersed in the poly(ether sulfone)–polyvinylpyrrolidone (PES–PVP) matrix, forming a hybrid PWA–NH2–HMS/PES–PVP nanocomposite membrane. The resultant...

  3. Bio-assisted synthesis of mesoporous Li3V2(PO4)3 for high performance lithium-ion batteries

    DEFF Research Database (Denmark)

    He, W.; Zhang, X.D.; Du, X.Y.

    2013-01-01

    The mesoporous biocarbon coated Li3V2(PO4)3(MBC-LVP) cathode material is synthesized by abiotemplate-assisted sol–gel reaction process using low-cost beer waste brewing yeasts (BWBYs) as bothstructural template and biocarbon source. The structure and electrochemical performances of MBC-LVPwere in...

  4. Benchmarking with high-order nodal diffusion methods

    International Nuclear Information System (INIS)

    Tomasevic, D.; Larsen, E.W.

    1993-01-01

    Significant progress in the solution of multidimensional neutron diffusion problems was made in the late 1970s with the introduction of nodal methods. Modern nodal reactor analysis codes provide significant improvements in both accuracy and computing speed over earlier codes based on fine-mesh finite difference methods. In the past, the performance of advanced nodal methods was determined by comparisons with fine-mesh finite difference codes. More recently, the excellent spatial convergence of nodal methods has permitted their use in establishing reference solutions for some important bench-mark problems. The recent development of the self-consistent high-order nodal diffusion method and its subsequent variational formulation has permitted the calculation of reference solutions with one node per assembly mesh size. In this paper, we compare results for four selected benchmark problems to those obtained by high-order response matrix methods and by two well-known state-of-the-art nodal methods (the open-quotes analyticalclose quotes and open-quotes nodal expansionclose quotes methods)

  5. A High-Order CFS Algorithm for Clustering Big Data

    Directory of Open Access Journals (Sweden)

    Fanyu Bu

    2016-01-01

    Full Text Available With the development of Internet of Everything such as Internet of Things, Internet of People, and Industrial Internet, big data is being generated. Clustering is a widely used technique for big data analytics and mining. However, most of current algorithms are not effective to cluster heterogeneous data which is prevalent in big data. In this paper, we propose a high-order CFS algorithm (HOCFS to cluster heterogeneous data by combining the CFS clustering algorithm and the dropout deep learning model, whose functionality rests on three pillars: (i an adaptive dropout deep learning model to learn features from each type of data, (ii a feature tensor model to capture the correlations of heterogeneous data, and (iii a tensor distance-based high-order CFS algorithm to cluster heterogeneous data. Furthermore, we verify our proposed algorithm on different datasets, by comparison with other two clustering schemes, that is, HOPCM and CFS. Results confirm the effectiveness of the proposed algorithm in clustering heterogeneous data.

  6. Ferroelectric BiFeO3as an Oxide Dye in Highly Tunable Mesoporous All-Oxide Photovoltaic Heterojunctions

    KAUST Repository

    Wang, Lingfei; Ma, He; Chang, Lei; Ma, Chun; Yuan, Guoliang; Wang, Junling; Wu, Tao

    2016-01-01

    As potential photovoltaic materials, transition-metal oxides such as BiFeO3 (BFO) are capable of absorbing a substantial portion of solar light and incorporating ferroic orders into solar cells with enhanced performance. But the photovoltaic

  7. Single-Crystal Mesoporous ZnO Thin Films Composed of Nanowalls

    KAUST Repository

    Wang, Xudong

    2009-02-05

    This paper presents a controlled, large scale fabrication of mesoporous ZnO thin films. The entire ZnO mesoporous film is one piece of a single crystal, while high porosity made of nanowalls is present. The growth mechanism was proposed in comparison with the growth of ZnO nanowires. The ZnO mesoporous film was successfully applied as a gas sensor. The fabrication and growth analysis of the mesoporous ZnO thin film gi ve general guidance for the controlled growth of nanostructures. It also pro vides a unique structure with a superhigh surface-to-volume ratio for surface-related applications. © 2009 American Chemical Society.

  8. Microwave radiation hydrothermal synthesis and characterization of micro- and mesoporous composite molecular sieve Y/SBA-15

    Directory of Open Access Journals (Sweden)

    Wenyuan Wu

    2017-05-01

    Full Text Available A microwave radiation hydrothermal method to control synthesis of micro- and mesoporous Y/SBA-15 composite molecular sieves was reported. The synthesized SBA-15 and Y/SBA-15 were characterized by scanning electron microscopy (SEM and N2 adsorption–desorption. The three kinds of different concentrations of hydrochloric acid (0.75 M, 2 M and 3.25 M were used to investigate the effect on Y/SBA-15. The analysis results of the composite products indicated that the optimization synthesis condition employed zeolite type Y and TEOS as silicon sources under 0.75 M hydrochloric acid by the microwave radiation hydrothermal synthesis method. The N2 adsorption–desorption test results of micro–mesoporous composite molecular sieve type Y/SBA-15 in mesoporous extent indicated that SBET is 355.529 m2/g, D‾BET is 4.050 nm, and mesoporous aperture focuses on the distribution region of 5.3 nm. It was found that the received composite product has an appropriate proportion of smaller size, larger size pore structure and the thicker pore wall. In addition, its internal channels have a high degree of order and smooth flow in long-range channels.

  9. Mesoporous materials as fining agents in variety Cabernet Sauvignon wines

    Directory of Open Access Journals (Sweden)

    Dumitriu Georgiana-Diana

    2016-01-01

    Full Text Available Innovative oenological products and techniques constantly need to be optimized in order to produce high quality wines that are able to fulfill the demanding consumers, with a pleasant colour, astringency, bitterness and a balanced organoleptic profile. New mesoporous materials with viability and environmental safety characteristics, might be a feasible alternative to the use of bentonite, while nowadays in the winemaking there is a major challenge caused by wastes derivate mainly from wine clarification stages. This study was aimed at investigating the influence of conventional (bentonite and activated coal and alternative (MCM-41, SBA-15, KIT-6 fining agents on enological parameters, colour, as well as on the antioxidant activity of a Cabernet Sauvignon wines. Our results show that mesoporous materials, KIT-6 and SBA-15 (6 g/L present the highest reduction on antioxidant activity with 23.08% and 24.41%, while bentonite and activated coal (1.5 g/L reduced with 20.72%, respectively 33.18%. Cluster analysis performed with the values of antioxidant activity differentiated wines treated with activated carbon from other wines.

  10. Ultrasound-driven design of new mesoporous metal catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Schaeferhans, Jana; Pazos Perez, Nicolas; Andreeva, Daria [Physikalische Chemie II, Univ. Bayreuth (Germany); Skorb, Ekaterina [Max-Planck-Institut fuer Kolloid- und Grenzflaechenforschung, Golm (Germany)

    2011-07-01

    Mesoporous metal nanocomposites were formed by a ''green chemistry'' method with ultrasound irradiation. The sonication technique combines the fabrication of a mesoporous support consisting of metallic particles (Al, Mg) several tens of micrometers in size and the subsequent incorporation of metal (Ag, Au, Pt etc.) nanoparticles into its pores. Next to filling the mesoporous support with particles we are also able to form mesoporous alloys e.g. AlNi or CoAlFe. The resulting material is analyzed by transmission electron microscopy, powder X-ray diffraction, small-angle neutron scattering and the Brunauer-Emmett-Teller and the Barrett-Joyner-Halenda method. Surface areas up to 200 m{sup 2}/g with a narrow pore size distribution around 3 nm can be achieved. The mesoporous structures are analyzed by confocal light microscopy after coloring the particles with dye. We explain the formation of the mesoporous inner structures by the following mechanism: Thermal etching and recrystallization of metals by ultrasound-stimulated high-speed jets of liquid form the porous structure that is stabilized by surface oxidation through free radicals generated during cavitation. We expect this approach to be universal and opening perspectives for a whole new class of catalytic materials that can be prepared in a fairly easy and cost effective way.

  11. Polycrystalline and Mesoporous 3-D Bi2O3 Nanostructured Negatrodes for High-Energy and Power-Asymmetric Supercapacitors: Superfast Room-Temperature Direct Wet Chemical Growth.