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Sample records for mesoporous oxide materials

  1. Oxidative dehydrogenation of ethane over vanadium supported on mesoporous materials of M41S family

    Czech Academy of Sciences Publication Activity Database

    Čapek, J.; Adam, J.; Grygar, Tomáš; Bulánek, R.; Vradman, L.; Košová-Kučerová, G.; Čičmanec, P.; Knotek, P.

    2008-01-01

    Roč. 342, 1-2 (2008), s. 99-106 ISSN 0926-860X Grant - others:GA ČR(CZ) GP104/07/P038 Program:GP Institutional research plan: CEZ:AV0Z40320502 Keywords : oxidative dehydrogenation * ethane * vanadium * mesoporous materials Subject RIV: CA - Inorganic Chemistry Impact factor: 3.190, year: 2008

  2. 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.

  3. 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.

  4. 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...

  5. 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.

  6. Synthesis of acid-base bifunctional mesoporous materials by oxidation and thermolysis

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Xiaofang [College of Chemistry, Jilin University, Jiefang Road 2519, Changchun 130023 (China); Zou, Yongcun [State Key Laboratory of Inoranic Synthesis and Preparative Chemistryg, College of Chemistry, Jilin University, Changchun 130012 (China); Wu, Shujie; Liu, Heng [College of Chemistry, Jilin University, Jiefang Road 2519, Changchun 130023 (China); Guan, Jingqi, E-mail: guanjq@jlu.edu.cn [College of Chemistry, Jilin University, Jiefang Road 2519, Changchun 130023 (China); Kan, Qiubin, E-mail: qkan@jlu.edu.cn [College of Chemistry, Jilin University, Jiefang Road 2519, Changchun 130023 (China)

    2011-06-15

    Graphical abstract: A novel and efficient method has been developed for the synthesis of acid-base bifunctional catalyst. The obtained sample of SO{sub 3}H-MCM-41-NH{sub 2} containing amine and sulfonic acids exhibits excellent catalytic activity in aldol condensation reaction. Research highlights: {yields} Synthesize acid-base bifunctional mesoporous materials SO{sub 3}H-MCM-41-NH{sub 2}. {yields} Oxidation and then thermolysis to generate acidic site and basic site. {yields} Exhibit good catalytic performance in aldol condensation reaction between acetone and various aldehydes. -- Abstract: A novel and efficient method has been developed for the synthesis of acid-base bifunctional catalyst SO{sub 3}H-MCM-41-NH{sub 2}. This method was achieved by co-condensation of tetraethylorthosilicate (TEOS), 3-mercaptopropyltrimethoxysilane (MPTMS) and (3-triethoxysilylpropyl) carbamicacid-1-methylcyclohexylester (3TAME) in the presence of cetyltrimethylammonium bromide (CTAB), followed by oxidation and then thermolysis to generate acidic site and basic site. X-ray diffraction (XRD) and transmission electron micrographs (TEM) show that the resultant materials keep mesoporous structure. Thermogravimetric analysis (TGA), X-ray photoelectron spectra (XPS), back titration, solid-state {sup 13}C CP/MAS NMR and solid-state {sup 29}Si MAS NMR confirm that the organosiloxanes were condensed as a part of the silica framework. The bifunctional sample (SO{sub 3}H-MCM-41-NH{sub 2}) containing amine and sulfonic acids exhibits excellent acid-basic properties, which make it possess high activity in aldol condensation reaction between acetone and various aldehydes.

  7. Synthesis and characterization of mesoporous materials for CO_2 capture: influence of nickel oxide

    International Nuclear Information System (INIS)

    Nascimento, Alexsandra Rodrigues do

    2014-01-01

    Several materials are currently under study for the CO_2 capture process, like the metal oxides and mixed metal oxides, zeolites, carbonaceous materials, metal-organic frameworks (MOF's) organosilica and modified silica surfaces. In this work, evaluated the adsorption capacity of CO_2 in mesoporous materials of different structures, such as MCM-48 and SBA-15 without impregnating and impregnated with nickel in the proportions 5 %, 10 % and 20 % (m/m), known as 5Ni-MCM-48, 10Ni-MCM-48, 20Ni-MCM-48 and 5Ni-SBA-15, 10Ni-SBA-15, 20Ni-SBA-15. The materials were characterized by means of X-ray diffraction (XRD), thermal analysis (TG and DTG), Fourier transform infrared spectroscopy (FT-IR), N_2 adsorption and desorption (BET) and scanning electron microscopy (SEM) with EDS. The adsorption process was performed varying the pressure of 100 - 4000 kPa and keeping the temperature constant and equal to 298 K. At a pressure of 100 kPa, higher concentrations of adsorption occurred for the materials 5Ni-MCM-48 (0.795 mmol g"-"1) and SBA-15 (0.914 mmol g"-"1) is not impregnated, and at a pressure of 4000 kPa for MCM-48 materials (14.89 mmol g"-"1) and SBA-15 (9.97 mmol g"-"1) not impregnated. The results showed that the adsorption capacity varies positively with the specific area, however, has a direct dependency on the type and geometry of the porous structure of channels. The data were fitted using the Langmuir and Freundlich models and were evaluated thermodynamic parameters Gibbs free energy and entropy of the adsorption system. (author)

  8. 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.

  9. Fabrication of mesoporous metal oxide coated-nanocarbon hybrid materials via a polyol-mediated self-assembly process

    Science.gov (United States)

    Feng, Bingmei; Wang, Huixin; Wang, Dongniu; Yu, Huilong; Chu, Yi; Fang, Hai-Tao

    2014-11-01

    After clarifying the formation mechanism of a typical metal glycolate precipitate, Ti glycolate, in a polyol-mediated synthesis using acetone as a precipitation medium, we describe a simple template-free approach based on an ethylene glycol-mediated synthesis to fabricate mesoporous metal oxide coated-nanocarbon hybrid materials including TiO2 coated-carbon nanotube (CNT), SnO2 coated-CNT, Cu2O/CuO coated-CNT and TiO2 coated-graphene sheet (GS). In the approach, metal oxide precursors, metal glycolates, were first deposited on CNTs or GSs, and subsequently transformed to the metal oxide coatings by pyrolysis or hydrolysis. By a comparison between the characterization of two TiO2-CNT hybrid materials using carboxylated CNTs and pristine CNTs without carboxyl groups, the driving force for initiating the deposition of metal glycolates on the carboxylated CNTs is confirmed to be the hydrogen bonding between the carboxyl groups and the polymer chains in metal glycolate sols. The electrochemical performances of the mesoporous TiO2 coated-carboxylated CNTs and TiO2-pristine CNT hybrid materials were investigated. The results show that the mesoporous TiO2 coated-carboxylated CNT with a uniform core-shell nanostructure exhibits substantial improvement in the rate performance in comparison with its counterpart from 0.5 C to 100 C because of its higher electronic conductivity and shorter diffusion path for the lithium ion. At the extremely high rate of 100 C, the specific capacity of TiO2 of the former reaches 85 mA h g-1, twice as high as that of the latter.After clarifying the formation mechanism of a typical metal glycolate precipitate, Ti glycolate, in a polyol-mediated synthesis using acetone as a precipitation medium, we describe a simple template-free approach based on an ethylene glycol-mediated synthesis to fabricate mesoporous metal oxide coated-nanocarbon hybrid materials including TiO2 coated-carbon nanotube (CNT), SnO2 coated-CNT, Cu2O/CuO coated-CNT and TiO2

  10. 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.

  11. 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

  12. 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.

  13. 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.

  14. Electroactive mesoporous yttria stabilized zirconia containing platinum or nickel oxide nanoclusters: a new class of solid oxide fuel cell electrode materials

    Energy Technology Data Exchange (ETDEWEB)

    Mamak, M.; Coombs, N.; Ozin, G.A. [Toronto Univ., ON (Canada). Dept. of Chemistry

    2001-02-01

    The electroactivity of surfactant-templated mesoporous yttria stabilized zirconia, containing nanoclusters of platinum or nickel oxide, is explored by alternating current (AC) complex impedance spectroscopy. The observed oxygen ion and mixed oxygen ion-electron charge-transport behavior for these materials, compared to the sintered-densified non-porous crystalline versions, is ascribed to the unique integration of mesoporosity and nanocrystallinity within the binary and ternary solid solution microstructure. These attributes inspire interest in this new class of materials as candidates for the development of improved performance solid oxide fuel cell electrodes. (orig.)

  15. 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.

  16. 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.

  17. 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.

  18. Magnetic mesoporous material for the sequestration of algae

    Science.gov (United States)

    Trewyn, Brian G.; Kandel, Kapil; Slowing, Igor Ivan; Lee, Show-Ling

    2014-09-09

    The present invention provides a magnetic mesoporous nanoparticle that includes a mesoporous silicate nanoparticle and iron oxide. The present invention also provides a method of using magnetic mesoporous nanoparticles to sequester microorganisms from a media.

  19. 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.

  20. One-pot hydrothermal synthesis of mesoporous Zn(x)Cd(1-x)S/reduced graphene oxide hybrid material and its enhanced photocatalytic activity.

    Science.gov (United States)

    Wang, Xinwei; Tian, Hongwei; Cui, Xiaoqiang; Zheng, Weitao; Liu, Yichun

    2014-09-14

    We successfully synthesized mesoporous Zn(x)Cd(1-x)S/reduced graphene oxide (Z(x)CSG) hybrid materials as photocatalysts using a facile one-pot hydrothermal reaction, in which graphene oxide (GO) was easily reduced (RGO), and simultaneously Zn(x)Cd(1-x)S (Z(x)CS) nanoparticles (NPs) with a mesoporous structure were uniformly dispersed on the RGO sheets. By well tuning the band gap from 3.42 to 2.21 eV by changing the molar ratio of Zn/Cd (or Zn content), Z(x)CSG with an optimal zinc content has been found to have a significant absorption in the visible light (VL) region. In addition, under VL irradiation (λ > 420 nm), Z(x)CSG also showed zinc content-dependent photocatalytic efficiencies for the degradation of methylene blue (MB). Our findings are that, among Z(x)CSG, Z(0.4)CSG displayed not only a superior photodegradation efficiency of MB (98%), but also good removal efficiency of total organic carbon (TOC) (67%). Furthermore, Z(0.4)CSG had a high photocatalytic stability, and could be used repeatedly. The enhanced photocatalytic activity for Z(0.4)CSG could be attributed to a synergistic effect between mesoporous Z(x)CS NPs and RGO, including the optimal band gap and the moderate conduction band position for ZxCS (compared to CdS), efficient separation and transfer ability of photogenerated electron/hole pairs in the presence of RGO sheets, and relatively high surface area for both mesoporous Z(x)CS NPs and RGO.

  1. The Synthesis, Characterization and Catalytic Reaction Studies of Monodisperse Platinum Nanoparticles in Mesoporous Oxide Materials

    Energy Technology Data Exchange (ETDEWEB)

    Rioux, Robert M. [Univ. of California, Berkeley, CA (United States)

    2006-01-01

    A catalyst design program was implemented in which Pt nanoparticles, either of monodisperse size and/or shape were synthesized, characterized and studied in a number of hydrocarbon conversion reactions. The novel preparation of these materials enables exquisite control over their physical and chemical properties that could be controlled (and therefore rationally tuned) during synthesis. The ability to synthesize rather than prepare catalysts followed by thorough characterization enable accurate structure-function relationships to be elucidated. This thesis emphasizes all three aspects of catalyst design: synthesis, characterization and reactivity studies. The precise control of metal nanoparticle size, surface structure and composition may enable the development of highly active and selective heterogeneous catalysts.

  2. Al-doped TiO{sub 2} mesoporous material supported Pd with enhanced catalytic activity for complete oxidation of ethanol

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Jing, E-mail: mlczjsls123@163.com; Mu, Wentao, E-mail: mwt15035687833@163.com; Su, Liqing, E-mail: suliqing0163@163.com; Li, Xingying, E-mail: lixingying0479@link.tyut.edu.cn; Guo, Yuyu, E-mail: guoyuyu0455@link.tyut.edu.cn; Zhang, Shen, E-mail: zhangshen0472@link.tyut.edu.cn; Li, Zhe, E-mail: lizhe@tyut.edu.cn

    2017-04-15

    Pd catalysts supported on Al-doped TiO{sub 2} mesoporous materials were evaluated in complete oxidation of ethanol. The catalysts synthesized by wet impregnation based on evaporation-induced self-assembly were characterized by X-ray diffraction, measurement of pore structure, XPS, FT-IR, temperature programmed reduction and TEM. Characteristic results showed that the aluminium was doped into the lattice of mesoporous anatase TiO{sub 2} to form Al-O-Ti defect structure. Catalytic results revealed that Al-doped catalysts were much more active than the pristine one, especially at low temperature (≤200 °C). This should be ascribed to the introduction of aluminium ions that suppressed the strong metal-support interaction and increased the active sites of Pd oxides, enhanced the stabilized anatase TiO{sub 2}, improved well dispersed high valence palladium species with high reducibility and enriched chemisorption oxygen. - Graphical abstract: Al-doped Pd/TiO{sub 2} exhibited optimal catalytic performance for ethanol oxidation and CO{sub 2} yield by the suppression of SMSI. - Highlights: • Palladium catalysts supported on Al-doped TiO{sub 2} mesoporous materials were studied. • The introduction of Al can enhance anatase stabilization and increase defect TiO{sub 2}. • The Pd/Al-TiO{sub 2} catalysts show higher ethanol conversion and CO{sub 2} yield than Pd/TiO{sub 2}. • The influence of Al on SMSI and catalytic performance were evaluated by TPR and XPS.

  3. Mesoporous metal oxides and processes for preparation thereof

    Energy Technology Data Exchange (ETDEWEB)

    Suib, Steven L.; Poyraz, Altug Suleyman

    2018-03-06

    A process for preparing a mesoporous metal oxide, i.e., transition metal oxide. Lanthanide metal oxide, a post-transition metal oxide and metalloid oxide. The process comprises providing an acidic mixture comprising a metal precursor, an interface modifier, a hydrotropic ion precursor, and a surfactant; and heating the acidic mixture at a temperature and for a period of time sufficient to form the mesoporous metal oxide. A mesoporous metal oxide prepared by the above process. A method of controlling nano-sized wall crystallinity and mesoporosity in mesoporous metal oxides. The method comprises providing an acidic mixture comprising a metal precursor, an interface modifier, a hydrotropic ion precursor, and a surfactant; and heating the acidic mixture at a temperature and for a period of time sufficient to control nano-sized wall crystallinity and mesoporosity in the mesoporous metal oxides. Mesoporous metal oxides and a method of tuning structural properties of mesoporous metal oxides.

  4. 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

  5. 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

  6. Mesoporous CuO–ZnO binary metal oxide nanocomposite for decontamination of sulfur mustard

    International Nuclear Information System (INIS)

    Praveen Kumar, J.; Prasad, G.K.; Ramacharyulu, P.V.R.K.; Garg, P.; Ganesan, K.

    2013-01-01

    Mesoporous CuO–ZnO binary metal oxide nanocomposites were studied as sorbent decontaminants against sulfur mustard, a well known chemical warfare agent. They were prepared by precipitation pyrolysis method and characterized by means of X-ray diffraction, transmission electron microscopy, nitrogen adsorption, Fourier transform infrared spectroscopy techniques. Obtained data indicated the presence of mesopores with diameter ranging from 2 to 80 nm and the materials exhibited relatively high surface area 86 m 2 g −1 when compared to the individual metal oxide nanoparticles. Reactive sites of mesoporous CuO–ZnO binary metal oxide nanocomposites were studied by infrared spectroscopy technique using pyridine as a probe molecule. These materials demonstrated superior decontamination properties against sulfur mustard when compared to single component metal oxides and decontaminated it to divinyl sulfide, chloroethyl vinyl sulfide, hemisulfur mustard, etc. - Graphical abstract: Mesoporous CuO–ZnO binary metal oxide nanocomposites were studied as sorbent decontaminants against sulfur mustard, a well known chemical warfare agent. These materials demonstrated superior decontamination properties against sulfur mustard and decontaminated it to divinyl sulfide, chloroethyl vinyl sulfide, hemisulfur mustard, etc. - Highlights: • Preparation of mesoporous CuO–ZnO binary metal oxide nanocomposite. • CuO–ZnO with better surface area was synthesized by precipitation pyrolysis. • Decontamination of HD using mesoporous CuO–ZnO binary metal oxide nanocomposite. • HD decontaminated by elimination and hydrolysis reactions

  7. Mesoporous CuO–ZnO binary metal oxide nanocomposite for decontamination of sulfur mustard

    Energy Technology Data Exchange (ETDEWEB)

    Praveen Kumar, J.; Prasad, G.K., E-mail: gkprasad2001@yahoo.com; Ramacharyulu, P.V.R.K.; Garg, P.; Ganesan, K.

    2013-11-01

    Mesoporous CuO–ZnO binary metal oxide nanocomposites were studied as sorbent decontaminants against sulfur mustard, a well known chemical warfare agent. They were prepared by precipitation pyrolysis method and characterized by means of X-ray diffraction, transmission electron microscopy, nitrogen adsorption, Fourier transform infrared spectroscopy techniques. Obtained data indicated the presence of mesopores with diameter ranging from 2 to 80 nm and the materials exhibited relatively high surface area 86 m{sup 2} g{sup −1} when compared to the individual metal oxide nanoparticles. Reactive sites of mesoporous CuO–ZnO binary metal oxide nanocomposites were studied by infrared spectroscopy technique using pyridine as a probe molecule. These materials demonstrated superior decontamination properties against sulfur mustard when compared to single component metal oxides and decontaminated it to divinyl sulfide, chloroethyl vinyl sulfide, hemisulfur mustard, etc. - Graphical abstract: Mesoporous CuO–ZnO binary metal oxide nanocomposites were studied as sorbent decontaminants against sulfur mustard, a well known chemical warfare agent. These materials demonstrated superior decontamination properties against sulfur mustard and decontaminated it to divinyl sulfide, chloroethyl vinyl sulfide, hemisulfur mustard, etc. - Highlights: • Preparation of mesoporous CuO–ZnO binary metal oxide nanocomposite. • CuO–ZnO with better surface area was synthesized by precipitation pyrolysis. • Decontamination of HD using mesoporous CuO–ZnO binary metal oxide nanocomposite. • HD decontaminated by elimination and hydrolysis reactions.

  8. Mesoporous tertiary oxides via a novel amphiphilic approach

    Energy Technology Data Exchange (ETDEWEB)

    Bennett, Natasha; Hall, Simon R., E-mail: simon.hall@bristol.ac.uk, E-mail: Annela.Seddon@bristol.ac.uk [Bristol Centre for Functional Nanomaterials, Centre for Nanoscience and Quantum Information, Tyndall Avenue, Bristol BS8 1FD, United Kingdom and Complex Functional Materials Group, School of Chemistry, University of Bristol, Bristol BS8 1TS (United Kingdom); Seddon, Annela M., E-mail: simon.hall@bristol.ac.uk, E-mail: Annela.Seddon@bristol.ac.uk; Hallett, James E. [H.H. Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol BS8 1TL (United Kingdom); Kockelmann, Winfried [STFC Rutherford Appleton Laboratory, Chilton OX11 0QX (United Kingdom); Ting, Valeska P. [Department of Chemical Engineering, University of Bath, Bath BA2 7AY (United Kingdom); Sadasivan, Sajanikumari; Tooze, Robert P. [Sasol Technology (UK) Ltd, Purdie Building, North Haugh, St Andrews, Fife KY16 9ST (United Kingdom)

    2016-01-01

    We report a facile biomimetic sol-gel synthesis using the sponge phase formed by the lipid monoolein as a structure-directing template, resulting in high phase purity, mesoporous dysprosium- and gadolinium titanates. The stability of monoolein in a 1,4-butanediol and water mixture complements the use of a simple sol-gel metal oxide synthesis route. By judicious control of the lipid/solvent concentration, the sponge phase of monoolein can be directly realised in the pyrochlore material, leading to a porous metal oxide network with an average pore diameter of 10 nm.

  9. Preparation and characterization of multifunctional magnetic mesoporous calcium silicate materials

    International Nuclear Information System (INIS)

    Zhang, Jianhua; Tao, Cuilian; Zhu, Yufang; Zhu, Min; Li, Jie; Hanagata, Nobutaka

    2013-01-01

    We have prepared multifunctional magnetic mesoporous Fe–CaSiO 3 materials using triblock copolymer (P123) as a structure-directing agent. The effects of Fe substitution on the mesoporous structure, in vitro bioactivity, magnetic heating ability and drug delivery property of mesoporous CaSiO 3 materials were investigated. Mesoporous Fe–CaSiO 3 materials had similar mesoporous channels (5–6 nm) with different Fe substitution. When 5 and 10% Fe were substituted for Ca in mesoporous CaSiO 3 materials, mesoporous Fe–CaSiO 3 materials still showed good apatite-formation ability and had no cytotoxic effect on osteoblast-like MC3T3-E1 cells evaluated by the elution cell culture assay. On the other hand, mesoporous Fe–CaSiO 3 materials could generate heat to raise the temperature of the surrounding environment in an alternating magnetic field due to their superparamagnetic property. When we use gentamicin (GS) as a model drug, mesoporous Fe–CaSiO 3 materials release GS in a sustained manner. Therefore, magnetic mesoporous Fe–CaSiO 3 materials would be a promising multifunctional platform with bone regeneration, local drug delivery and magnetic hyperthermia. (paper)

  10. Synthesis and catalytic applications of combined zeolitic/mesoporous materials

    Directory of Open Access Journals (Sweden)

    Jarian Vernimmen

    2011-11-01

    Full Text Available In the last decade, research concerning nanoporous siliceous materials has been focused on mesoporous materials with intrinsic zeolitic features. These materials are thought to be superior, because they are able to combine (i the enhanced diffusion and accessibility for larger molecules and viscous fluids typical of mesoporous materials with (ii the remarkable stability, catalytic activity and selectivity of zeolites. This review gives an overview of the state of the art concerning combined zeolitic/mesoporous materials. Focus is put on the synthesis and the applications of the combined zeolitic/mesoporous materials. The different synthesis approaches and formation mechanisms leading to these materials are comprehensively discussed and compared. Moreover, Ti-containing nanoporous materials as redox catalysts are discussed to illustrate a potential implementation of combined zeolitic/mesoporous materials.

  11. Aspirin degradation in surface-charged TEMPO-oxidized mesoporous crystalline nanocellulose.

    Science.gov (United States)

    Carlsson, Daniel O; Hua, Kai; Forsgren, Johan; Mihranyan, Albert

    2014-01-30

    TEMPO-mediated surface oxidation of mesoporous highly crystalline Cladophora cellulose was used to introduce negative surface charges onto cellulose nanofibrils without significantly altering other structural characteristics. This enabled the investigation of the influence of mesoporous nanocellulose surface charges on aspirin chemical stability to be conducted. The negative surface charges (carboxylate content 0.44±0.01 mmol/g) introduced on the mesoporous crystalline nanocellulose significantly accelerated aspirin degradation, compared to the starting material which had significantly less surface charge (0.06±0.01 mmol/g). This effect followed from an increased aspirin amorphisation ability in mesopores of the oxidized nanocellulose. These results highlight the importance of surface charges in formulating nanocellulose for drug delivery. Copyright © 2013 Elsevier B.V. All rights reserved.

  12. 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)

  13. Hexamethyldisilazane Removal with Mesoporous Materials Prepared from Calcium Fluoride Sludge.

    Science.gov (United States)

    Kao, Ching-Yang; Lin, Min-Fa; Nguyen, Nhat-Thien; Tsai, Hsiao-Hsin; Chang, Luh-Maan; Chen, Po-Han; Chang, Chang-Tang

    2018-05-01

    A large amount of calcium fluoride sludge is generated by the semiconductor industry every year. It also requires a high amount of fuel consumption using rotor concentrators and thermal oxidizers to treat VOCs. The mesoporous adsorbent prepared by calcium fluoride sludge was used for VOCs treatment. The semiconductor industry employs HMDS to promote the adhesion of photo-resistant material to oxide(s) due to the formation of silicon dioxide, which blocks porous adsorbents. The adsorption of HMDS (Hexamethyldisiloxane) was tested with mesoporous silica materials synthesized from calcium fluoride (CF-MCM). The resulting samples were characterized by XRD, XRF, FTIR, N2-adsorption-desorption techniques. The prepared samples possessed high specific surface area, large pore volume and large pore diameter. The crystal patterns of CF-MCM were similar with Mobil composite matter (MCM-41) from TEM image. The adsorption capacity of HMDS with CF-MCM was 40 and 80 mg g-1, respectively, under 100 and 500 ppm HMDS. The effects of operation parameters, such as contact time and mixture concentration, on the performance of CF-MCM were also discussed in this study.

  14. Preparation of mesoporous carbon/polypyrrole composite materials and their supercapacitive properties

    Directory of Open Access Journals (Sweden)

    WU-JUN ZOU

    2011-08-01

    Full Text Available We synthesized mesoporous carbons/polypyrrole composites, using a chemical oxidative polymerization and calcium carbonate as a sacrificial template. N2 adsorption-desorption method, Fourier infrared spectroscopy, and transmission electron microscopy were used to characterize the structure and morphology of the composites. The measurement results indicated that as-synthesized carbon with the disordered mesoporous structure and a pore size of approximately 5 nm was uniformly coated by polypyrrole. The electrochemical behavior of the resulting composite was examined by cyclic voltammetry and cycle life measurements, and the obtained results showed that the specific capacitance of the resulting composite electrode was as high as 313 F g−1, nearly twice the capacitance of pure mesoporous carbon electrode (163 F g–1. This reveals that the electrochemical performance of these materials is governed by a combination of the electric double layer capacitance of mesoporous carbon and pseudocapacitance of polypyrrole.

  15. Mesoporous materials for clean energy technologies.

    Science.gov (United States)

    Linares, Noemi; Silvestre-Albero, Ana M; Serrano, Elena; Silvestre-Albero, Joaquín; García-Martínez, Javier

    2014-11-21

    Alternative energy technologies are greatly hindered by significant limitations in materials science. From low activity to poor stability, and from mineral scarcity to high cost, the current materials are not able to cope with the significant challenges of clean energy technologies. However, recent advances in the preparation of nanomaterials, porous solids, and nanostructured solids are providing hope in the race for a better, cleaner energy production. The present contribution critically reviews the development and role of mesoporosity in a wide range of technologies, as this provides for critical improvements in accessibility, the dispersion of the active phase and a higher surface area. Relevant examples of the development of mesoporosity by a wide range of techniques are provided, including the preparation of hierarchical structures with pore systems in different scale ranges. Mesoporosity plays a significant role in catalysis, especially in the most challenging processes where bulky molecules, like those obtained from biomass or highly unreactive species, such as CO2 should be transformed into most valuable products. Furthermore, mesoporous materials also play a significant role as electrodes in fuel and solar cells and in thermoelectric devices, technologies which are benefiting from improved accessibility and a better dispersion of materials with controlled porosity.

  16. 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.

  17. 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.

  18. A novel, efficient and facile method for the template removal from mesoporous materials

    KAUST Repository

    Chen, Lu; Jiang, Shang; Wang, Runwei; Zhang, Zongtao; Qiu, Shilun

    2014-01-01

    © 2014, Jilin University, The Editorial Department of Chemical Research in Chinese Universities and Springer-Verlag GmbH. A new catalytic-oxidation method was adopted to remove the templates from SBA-15 and MCM-41 mesoporous materials via Fenton

  19. Mesoporous metal oxide microsphere electrode compositions and their methods of making

    Science.gov (United States)

    Parans Paranthaman, Mariappan; Bi, Zhonghe; Bridges, Craig A.; Brown, Gilbert M.

    2017-04-11

    Compositions and methods of making are provided for treated mesoporous metal oxide microspheres electrodes. The compositions include microspheres with an average diameter between about 200 nanometers and about 10 micrometers and mesopores on the surface and interior of the microspheres. The methods of making include forming a mesoporous metal oxide microsphere composition and treating the mesoporous metal oxide microspheres by at least annealing in a reducing atmosphere, doping with an aliovalent element, and coating with a coating composition.

  20. Study of Horseradish Peroxidase Fixed on Mesoporous Materials as a Chemical Reaction Catalyst

    Science.gov (United States)

    Gao, Mengdan; Dai, Rongji

    2017-12-01

    Nanostructured mesoporous materials is a new type of porous materials, which has been widely used. It has excellent capability in enzymes immobilization, but modification on the chemical bonds of the enzyme reduce the enzymatic activity and rarely used in chemical reactions. The horseradish peroxidase was immobilized on the mesoporous materials with appropriate aperture and its activity and stability was evaluated when catalyzing the nitration reaction of amines and oxidation reaction of thiourea. The optimum mesoporous material to fix the horseradish peroxidase can be obtained by mixing polyoxyethylene - polyoxypropylene-pol, yoxyethylene(P123), 1,3,5-trimethylbenzene(TMB), and tetramethoxysilane (TMOS) at a ratio of 10:1:1, whose surface area and pore volume and pore diameter calculated by BET and BJH model were 402.903m2/g, 1.084cm2/g, 1.084cm2/g respectively. The horseradish peroxidase, immobilized on the mesoporous materials, was applied for catalyzing the nitration reaction of anilines and oxidation reaction of thiourea, produced a high product yield and can be recycled. Thus, it is a strong candidate as a catalysts for oxidation reactions, to be produced at industral scale, due to its high efficiency and low cost.

  1. A novel, efficient and facile method for the template removal from mesoporous materials

    KAUST Repository

    Chen, Lu

    2014-11-12

    © 2014, Jilin University, The Editorial Department of Chemical Research in Chinese Universities and Springer-Verlag GmbH. A new catalytic-oxidation method was adopted to remove the templates from SBA-15 and MCM-41 mesoporous materials via Fenton-like techniques under microwave irradiation. The mesoporous silica materials were treated with different Fenton agents based on the template’s property and textural property. The samples were characterized by powder X-ray diffraction(XRD) measurement, N2 adsorption-desorption isotherms, infrared spectroscopy, 29Si MAS NMR and thermo gravimetric analysis(TGA). The results reveal that this is an efficient and facile approach to the thorough template-removal from mesoporous silica materials, as well as to offering products with more stable structures, higher BET surface areas, larger pore volumes and larger quantity of silanol groups.

  2. Structured mesoporous Mn, Fe, and Co oxides: Synthesis, physicochemical, and catalytic properties

    Science.gov (United States)

    Maerle, A. A.; Karakulina, A. A.; Rodionova, L. I.; Moskovskaya, I. F.; Dobryakova, I. V.; Egorov, A. V.; Romanovskii, B. V.

    2014-02-01

    Structured mesoporous Mn, Fe, and Co oxides are synthesized using "soft" and "hard" templates; the resulting materials are characterized by XRD, SEM, TEM, BET, and TG. It is shown that in the first case, the oxides have high surface areas of up to 450 m2/g that are preserved after calcination of the material up to 300°C. Even though, the surface area of the oxides prepared by the "hard-template" method does not exceed 100 m2/g; it is, however, thermally stable up to 500°C. Catalytic activity of mesoporous oxides in methanol conversion was found to depend on both the nature of the transition metal and the type of template used in synthesis.

  3. 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.

  4. Electrochemical Synthesis of Mesoporous CoPt Nanowires for Methanol Oxidation

    Directory of Open Access Journals (Sweden)

    Albert Serrà

    2014-03-01

    Full Text Available A new electrochemical method to synthesize mesoporous nanowires of alloys has been developed. Electrochemical deposition in ionic liquid-in-water (IL/W microemulsion has been successful to grow mesoporous CoPt nanowires in the interior of polycarbonate membranes. The viscosity of the medium was high, but it did not avoid the entrance of the microemulsion in the interior of the membrane’s channels. The structure of the IL/W microemulsions, with droplets of ionic liquid (4 nm average diameter dispersed in CoPt aqueous solution, defined the structure of the nanowires, with pores of a few nanometers, because CoPt alloy deposited only from the aqueous component of the microemulsion. The electrodeposition in IL/W microemulsion allows obtaining mesoporous structures in which the small pores must correspond to the size of the droplets of the electrolytic aqueous component of the microemulsion. The IL main phase is like a template for the confined electrodeposition. The comparison of the electrocatalytic behaviours towards methanol oxidation of mesoporous and compact CoPt nanowires of the same composition, demonstrated the porosity of the material. For the same material mass, the CoPt mesoporous nanowires present a surface area 16 times greater than compact ones, and comparable to that observed for commercial carbon-supported platinum nanoparticles.

  5. 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

  6. Mesoporous tin-doped indium oxide thin films: effect of mesostructure on electrical conductivity

    Directory of Open Access Journals (Sweden)

    Till von Graberg, Pascal Hartmann, Alexander Rein, Silvia Gross, Britta Seelandt, Cornelia Röger, Roman Zieba, Alexander Traut, Michael Wark, Jürgen Janek and Bernd M Smarsly

    2011-01-01

    Full Text Available We present a versatile method for the preparation of mesoporous tin-doped indium oxide (ITO thin films via dip-coating. Two poly(isobutylene-b-poly(ethyleneoxide (PIB-PEO copolymers of significantly different molecular weight (denoted as PIB-PEO 3000 and PIB-PEO 20000 are used as templates and are compared with non-templated films to clarify the effect of the template size on the crystallization and, thus, on the electrochemical properties of mesoporous ITO films. Transparent, mesoporous, conductive coatings are obtained after annealing at 500 °C; these coatings have a specific resistance of 0.5 Ω cm at a thickness of about 100 nm. Electrical conductivity is improved by one order of magnitude by annealing under a reducing atmosphere. The two types of PIB-PEO block copolymers create mesopores with in-plane diameters of 20–25 and 35–45 nm, the latter also possessing correspondingly thicker pore walls. Impedance measurements reveal that the conductivity is significantly higher for films prepared with the template generating larger mesopores. Because of the same size of the primary nanoparticles, the enhanced conductivity is attributed to a higher conduction path cross section. Prussian blue was deposited electrochemically within the films, thus confirming the accessibility of their pores and their functionality as electrode material.

  7. 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.

  8. Mesoporous cerium oxide nanospheres for the visible-light driven photocatalytic degradation of dyes

    Directory of Open Access Journals (Sweden)

    Subas K. Muduli

    2014-04-01

    Full Text Available A facile, solvothermal synthesis of mesoporous cerium oxide nanospheres is reported for the purpose of the photocatalytic degradation of organic dyes and future applications in sustainable energy research. The earth-abundant, relatively affordable, mixed valence cerium oxide sample, which consists of predominantly Ce7O12, has been characterized by powder X-ray diffraction, X-ray photoelectron and UV–vis spectroscopy, and transmission electron microscopy. Together with N2 sorption experiments, the data confirms that the new cerium oxide material is mesoporous and absorbs visible light. The photocatalytic degradation of rhodamin B is investigated with a series of radical scavengers, suggesting that the mechanism of photocatalytic activity under visible-light irradiation involves predominantly hydroxyl radicals as the active species.

  9. Oxidative nanopatterning of titanium generates mesoporous surfaces with antimicrobial properties

    Directory of Open Access Journals (Sweden)

    Variola F

    2014-05-01

    Full Text Available Fabio Variola,1,2 Sylvia Francis Zalzal,3 Annie Leduc,3 Jean Barbeau,3 Antonio Nanci31Faculty of Engineering, Department of Mechanical Engineering, 2Faculty of Science, Department of Physics, University of Ottawa, Ottawa, ON, 3Faculty of Dental Medicine, Université de Montréal, Montreal, QC, CanadaAbstract: Mesoporous surfaces generated by oxidative nanopatterning have the capacity to selectively regulate cell behavior, but their impact on microorganisms has not yet been explored. The main objective of this study was to test the effects of such surfaces on the adherence of two common bacteria and one yeast strain that are responsible for nosocomial infections in clinical settings and biomedical applications. In addition, because surface characteristics are known to affect bacterial adhesion, we further characterized the physicochemical properties of the mesoporous surfaces. Focused ion beam (FIB was used to generate ultrathin sections for elemental analysis by energy-dispersive X-ray spectroscopy (EDS, nanobeam electron diffraction (NBED, and high-angle annular dark field (HAADF scanning transmission electron microscopy (STEM imaging. The adherence of Staphylococcus aureus, Escherichia coli and Candida albicans onto titanium disks with mesoporous and polished surfaces was compared. Disks with the two surfaces side-by-side were also used for direct visual comparison. Qualitative and quantitative results from this study indicate that bacterial adhesion is significantly hindered by the mesoporous surface. In addition, we provide evidence that it alters structural parameters of C. albicans that determine its invasiveness potential, suggesting that microorganisms can sense and respond to the mesoporous surface. Our findings demonstrate the efficiency of a simple chemical oxidative treatment in generating nanotextured surfaces with antimicrobial capacity with potential applications in the implant manufacturing industry and hospital setting

  10. Kinetic and catalytic analysis of mesoporous metal oxides on the oxidation of Rhodamine B

    Science.gov (United States)

    Xaba, Morena S.; Noh, Ji-Hyang; Mokgadi, Keabetswe; Meijboom, Reinout

    2018-05-01

    In this study, we demonstrate the synthesis and catalytic activity of different mesoporous transition metal oxides, silica (SiO2), copper oxide (CuO), chromium oxide (Cr2O3), iron oxide (Fe2O3) cobalt oxide (Co3O4), cerium oxide (CeO2) and nickel oxide (NiO), on the oxidation of a pollutant dye, Rhodamine B (RhB). These metal oxides were synthesized by inverse micelle formation method and characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), adsorption-desorption isotherms (BET) and H2-temperature programmed reduction (TPR). UV-vis spectrophotometry was used to monitor the time-resolved absorbance of RhB at λmax = 554 nm. Mesoporous copper oxide was calcined at different final heating temperatures of 250, 350, 450 and 550 °C, and each mesoporous copper oxide catalyst showed unique physical properties and catalytic behavior. Mesoporous CuO-550 with the smallest characteristic path length δ, proved to be the catalyst of choice for the oxidation of RhB in aqueous media. We observed that the oxidation of RhB in aqueous media is dependent on the crystallite size and characteristic path length of the mesoporous metal oxide. The Langmuir-Hinshelwood model was used to fit the experimental data and to prove that the reaction occurs on the surface of the mesoporous CuO. The thermodynamic parameters, EA, ΔH#, ΔS# and ΔG# were calculated and catalyst recycling and reusability were demonstrated.

  11. 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

  12. Synthesis of Novel Mesoporous Silica Materials with Hierarchical Pore Structures

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, Suk Bon; Choi, Wang Kyu; Choi, Byung Seon; Moon, Jei Kwon [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2012-05-15

    Porous materials with various pore sizes in the range of micropore (< 2 nm), mesopore (2-50 nm), and macropore (> 50 nm) are attractive due to their many emerging applications such as catalysts, separation systems, and low dielectric constant materials. The discovery of new M41S mesoporous silica families with pore sizes larger than 2 nm in diameter in 1992 extended the applications into much wider pore ranges, bringing in a new prosperous era in porous material research. The synthesis of these silica materials has been mainly accomplished through a self-assembly between surfactant molecules and inorganic species under various pH conditions. Recently, core-shell nanoparticles with a silica core and mesoporous shell under basic conditions were synthesized using the silica nanoparticles as a core, and a silica precursor (TEOS) and cationic surfactant (CTABr) as a material for the formation of the mesoporous shell. The resultant materials were very monodispersive in size and showed a narrow pore size distribution in the range of ca 2-3 nm in diameter, depending on the alkyl-chain length of the surfactants used. In this work, the mesoporous shell coated-fumed silicas (denoted as MS M-5s) were synthesized by using fumed silica instead of the silica nanoparticle as a core based on previous reports. Also, the structural properties of the MS M-5s such as the specific surface area and pore volume were easily controlled by varying the amount of the silica precursor and surfactant. The resultant materials exhibited a BET surface area of ca 279-446 m{sup 2}/g and total pore volume of ca 0.64-0.74 cm{sup 3}/g and showed a narrow pore size distribution (PSD) due to the removal of the organic surfactant molecules

  13. Cumene cracking on modified mesoporous material type MCM-41

    African Journals Online (AJOL)

    AlMCM-41 materials, the method of its exchange mode and its grains form were investigated for the mesoporous catalytic activity in the cumene (i.e. isopropylbenzene) cracking reaction. Benzene, propylene and xylene derivatives are the main ...

  14. Gas-generated thermal oxidation of a coordination cluster for an anion-doped mesoporous metal oxide.

    Science.gov (United States)

    Hirai, Kenji; Isobe, Shigehito; Sada, Kazuki

    2015-12-18

    Central in material design of metal oxides is the increase of surface area and control of intrinsic electronic and optical properties, because of potential applications for energy storage, photocatalysis and photovoltaics. Here, we disclose a facile method, inspired by geochemical process, which gives rise to mesoporous anion-doped metal oxides. As a model system, we demonstrate that simple calcination of a multinuclear coordination cluster results in synchronic chemical reactions: thermal oxidation of Ti8O10(4-aminobenzoate)12 and generation of gases including amino-group fragments. The gas generation during the thermal oxidation of Ti8O10(4-aminobenzoate)12 creates mesoporosity in TiO2. Concurrently, nitrogen atoms contained in the gases are doped into TiO2, thus leading to the formation of mesoporous N-doped TiO2. The mesoporous N-doped TiO2 can be easily synthesized by calcination of the multinuclear coordination cluster, but shows better photocatalytic activity than the one prepared by a conventional sol-gel method. Owing to an intrinsic designability of coordination compounds, this facile synthetic will be applicable to a wide range of metal oxides and anion dopants.

  15. 3-D periodic mesoporous nickel oxide for nonenzymatic uric acid sensors with improved sensitivity

    Science.gov (United States)

    Huang, Wei; Cao, Yang; Chen, Yong; Zhou, Yang; Huang, Qingyou

    2015-12-01

    3-D periodic mesoporous nickel oxide (NiO) particles with crystalline walls have been synthesized through the microwave-assisted hard template route toward the KIT-6 silica. It was investigated as a nonenzymatic amperometric sensor for the detection of uric acid. 3-D periodic nickel oxide matrix has been obtained by the hard template route from the KIT-6 silica template. The crystalline nickel oxide belonged to the Ia3d space group, and its structure was characterized by X-ray diffraction (XRD), N2 adsorption-desorption, and transmission electron microscopy (TEM). The analysis results showed that the microwave-assisted mesoporous NiO materials were more appropriate to be electrochemical sensors than the traditional mesoporous NiO. Cyclic voltammetry (CV) revealed that 3-D periodic NiO exhibited a direct electrocatalytic activity for the oxidation of uric acid in sodium hydroxide solution. The enzyme-less amperometric sensor used in the detection of uric acid with detection limit of 0.005 μM (S/N = 3) over wide linear detection ranges up to 0.374 mM and with a high sensitivity of 756.26 μA mM-1 cm-2, and a possible mechanism was also given in the paper.

  16. Functionalized mesoporous silica materials for molsidomine adsorption: Thermodynamic study

    Energy Technology Data Exchange (ETDEWEB)

    Alyoshina, Nonna A.; Parfenyuk, Elena V., E-mail: evp@iscras.ru

    2013-09-15

    A series of unmodified and organically modified mesoporous silica materials was prepared. The unmodified mesoporous silica was synthesized via sol–gel synthesis in the presence of D-glucose as pore-forming agent. The functionalized by phenyl, aminopropyl and mercaptopropyl groups silica materials were prepared via grafting. The fabricated adsorbent materials were characterized by Fourier transform infrared spectroscopy (FTIR) analysis, N{sub 2} adsorption/desorption and elemental analysis methods. Then their adsorption properties for mesoionic dug molsidomine were investigated at 290–313 K and physiological pH value. Thermodynamic parameters of molsidomine adsorption on the synthesized materials have been calculated. The obtained results showed that the adsorption process of molsidomine on the phenyl modified silica is the most quantitatively and energetically favorable. The unmodified and mercaptopropyl modified silica materials exhibit significantly higher adsorption capacities and energies for molsidomine than the aminopropyl modified sample. The effects are discussed from the viewpoint of nature of specific interactions responsible for the adsorption. - Graphical abstract: Comparative analysis of the thermodynamic characteristics of molsidomine adsorption showed that the adsorption process on mesoporous silica materials is controlled by chemical nature of surface functional groups. Molsidomine adsorption on the phenyl modified silica is the most quantitatively and energetically favorable. Taking into account ambiguous nature of mesoionic compounds, it was found that molsidomine is rather aromatic than dipolar. Display Omitted - Highlights: • Unmodified and organically modified mesoporous silica materials were prepared. • Molsidomine adsorption on the silica materials was studied. • Phenyl modified silica shows the highest adsorption capacity and favorable energy. • Molsidomine exhibits the lowest affinity to aminopropyl modified silica.

  17. Functionalized mesoporous silica materials for molsidomine adsorption: Thermodynamic study

    International Nuclear Information System (INIS)

    Alyoshina, Nonna A.; Parfenyuk, Elena V.

    2013-01-01

    A series of unmodified and organically modified mesoporous silica materials was prepared. The unmodified mesoporous silica was synthesized via sol–gel synthesis in the presence of D-glucose as pore-forming agent. The functionalized by phenyl, aminopropyl and mercaptopropyl groups silica materials were prepared via grafting. The fabricated adsorbent materials were characterized by Fourier transform infrared spectroscopy (FTIR) analysis, N 2 adsorption/desorption and elemental analysis methods. Then their adsorption properties for mesoionic dug molsidomine were investigated at 290–313 K and physiological pH value. Thermodynamic parameters of molsidomine adsorption on the synthesized materials have been calculated. The obtained results showed that the adsorption process of molsidomine on the phenyl modified silica is the most quantitatively and energetically favorable. The unmodified and mercaptopropyl modified silica materials exhibit significantly higher adsorption capacities and energies for molsidomine than the aminopropyl modified sample. The effects are discussed from the viewpoint of nature of specific interactions responsible for the adsorption. - Graphical abstract: Comparative analysis of the thermodynamic characteristics of molsidomine adsorption showed that the adsorption process on mesoporous silica materials is controlled by chemical nature of surface functional groups. Molsidomine adsorption on the phenyl modified silica is the most quantitatively and energetically favorable. Taking into account ambiguous nature of mesoionic compounds, it was found that molsidomine is rather aromatic than dipolar. Display Omitted - Highlights: • Unmodified and organically modified mesoporous silica materials were prepared. • Molsidomine adsorption on the silica materials was studied. • Phenyl modified silica shows the highest adsorption capacity and favorable energy. • Molsidomine exhibits the lowest affinity to aminopropyl modified silica

  18. Comparative study of hydrogen storage on metal doped mesoporous materials

    Science.gov (United States)

    Carraro, P. M.; Sapag, K.; Oliva, M. I.; Eimer, G. A.

    2018-06-01

    The hydrogen adsorption capacity of mesoporous materials MCM-41 modified with Co, Fe, Ti, Mg and Ni at 77 K and 10 bar was investigated. Various techniques including XRD, N2 adsorption and DRUV-vis were employed for the materials characterization. The results showed that a low nickel loading on MCM-41 support promoted the presence of hydrogen-favorable sites, increasing the hydrogen storage capacity.

  19. Mesoporous nickel oxide nanowires: hydrothermal synthesis, characterisation and applications for lithium-ion batteries and supercapacitors with superior performance.

    Science.gov (United States)

    Su, Dawei; Kim, Hyun-Soo; Kim, Woo-Seong; Wang, Guoxiu

    2012-06-25

    Mesoporous nickel oxide nanowires were synthesized by a hydrothermal reaction and subsequent annealing at 400 °C. The porous one-dimensional nanostructures were analysed by field-emission SEM, high-resolution TEM and N(2) adsorption/desorption isotherm measurements. When applied as the anode material in lithium-ion batteries, the as-prepared mesoporous nickel oxide nanowires demonstrated outstanding electrochemical performance with high lithium storage capacity, satisfactory cyclability and an excellent rate capacity. They also exhibited a high specific capacitance of 348 F g(-1) as electrodes in supercapacitors. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. 3-D periodic mesoporous nickel oxide for nonenzymatic uric acid sensors with improved sensitivity

    International Nuclear Information System (INIS)

    Huang, Wei; Cao, Yang; Chen, Yong; Zhou, Yang; Huang, Qingyou

    2015-01-01

    Graphical abstract: The enzyme-less amperometric sensor based on 3-D periodic mesoporous NiO nanomaterials used in the detection of uric acid with detection limit of 0.005 μM (S/N = 3) over wide linear detection ranges up to 0.374 mM and with a high sensitivity of 756.26 μA mM"−"1 cm"−"2. - Highlights: • Microwave-assisted method was used to fabricate the 3-D periodic mesoporous NiO particles. • The mesoporous nickel oxide was applied to nonenzymatic uric acid biosensor. • The detection limit is 0.005 μM over wide linear detection ranges up to 0.374 mM. • The sensitivity is 756.26 μA mM"−"1 cm"−"2. - Abstract: 3-D periodic mesoporous nickel oxide (NiO) particles with crystalline walls have been synthesized through the microwave-assisted hard template route toward the KIT-6 silica. It was investigated as a nonenzymatic amperometric sensor for the detection of uric acid. 3-D periodic nickel oxide matrix has been obtained by the hard template route from the KIT-6 silica template. The crystalline nickel oxide belonged to the Ia3d space group, and its structure was characterized by X-ray diffraction (XRD), N_2 adsorption–desorption, and transmission electron microscopy (TEM). The analysis results showed that the microwave-assisted mesoporous NiO materials were more appropriate to be electrochemical sensors than the traditional mesoporous NiO. Cyclic voltammetry (CV) revealed that 3-D periodic NiO exhibited a direct electrocatalytic activity for the oxidation of uric acid in sodium hydroxide solution. The enzyme-less amperometric sensor used in the detection of uric acid with detection limit of 0.005 μM (S/N = 3) over wide linear detection ranges up to 0.374 mM and with a high sensitivity of 756.26 μA mM"−"1 cm"−"2, and a possible mechanism was also given in the paper.

  1. 3-D periodic mesoporous nickel oxide for nonenzymatic uric acid sensors with improved sensitivity

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Wei; Cao, Yang, E-mail: caowang507@163.com; Chen, Yong; Zhou, Yang; Huang, Qingyou

    2015-12-30

    Graphical abstract: The enzyme-less amperometric sensor based on 3-D periodic mesoporous NiO nanomaterials used in the detection of uric acid with detection limit of 0.005 μM (S/N = 3) over wide linear detection ranges up to 0.374 mM and with a high sensitivity of 756.26 μA mM{sup −1} cm{sup −2}. - Highlights: • Microwave-assisted method was used to fabricate the 3-D periodic mesoporous NiO particles. • The mesoporous nickel oxide was applied to nonenzymatic uric acid biosensor. • The detection limit is 0.005 μM over wide linear detection ranges up to 0.374 mM. • The sensitivity is 756.26 μA mM{sup −1} cm{sup −2}. - Abstract: 3-D periodic mesoporous nickel oxide (NiO) particles with crystalline walls have been synthesized through the microwave-assisted hard template route toward the KIT-6 silica. It was investigated as a nonenzymatic amperometric sensor for the detection of uric acid. 3-D periodic nickel oxide matrix has been obtained by the hard template route from the KIT-6 silica template. The crystalline nickel oxide belonged to the Ia3d space group, and its structure was characterized by X-ray diffraction (XRD), N{sub 2} adsorption–desorption, and transmission electron microscopy (TEM). The analysis results showed that the microwave-assisted mesoporous NiO materials were more appropriate to be electrochemical sensors than the traditional mesoporous NiO. Cyclic voltammetry (CV) revealed that 3-D periodic NiO exhibited a direct electrocatalytic activity for the oxidation of uric acid in sodium hydroxide solution. The enzyme-less amperometric sensor used in the detection of uric acid with detection limit of 0.005 μM (S/N = 3) over wide linear detection ranges up to 0.374 mM and with a high sensitivity of 756.26 μA mM{sup −1} cm{sup −2}, and a possible mechanism was also given in the paper.

  2. 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.

  3. Adsorption Of Water And Benzene Vapour In Mesoporous Materials

    Directory of Open Access Journals (Sweden)

    Paulina Taba

    2008-11-01

    Full Text Available Mesoporous materials have attracted the attention of many researchers due to the potential applications promised by the materials. This article discusses adsorption of water and benzene vapour in mesoporous materials (mesoporous silica: MCM-41, MCM-48 and their modification. MCM-41 and MCM-48 were synthesized hydrothermally at 100 oC using cethyltrimethylammonium chloride or dodecyltrimethylammonium bromide for MCM-41 (C16 or MCM-41 (C12 respectively and a mixture of cethyltrimethylammonium bromide and Triton X-100 for MCM-48 as templates. Their modifications were conducted by silylation of MCM-41 (C16 and MCM-48 with trimethylchloro silane (MCM16-TMCS and MCM48-TMCS and t-butyldimethylchloro silane (MCM16-TBDMCS and MCM48-TBDMCS. Results showed that MCM-41 and MCM-48 materials had hydrophobic features which were shown in the small amount of water adsorption at low P/P0. The hydrophobicity of samples used in this study decrease in the sequence: MCM-41 (C16 > MCM-48 > MCM-41 (C12. The hydrophobicity increased when MCM-41 and MCM-48 were silylated with TMCS or TBDMCS. All unsilylated MCM materials show higher affinity to benzene at low P/P0 than the silylated samples. The results of water and benzene adsorption showed that silylated samples are promising candidates as selective adsorbents for organic compounds.

  4. Formation of pyridine N-oxides using mesoporous titanium silicalite-1

    DEFF Research Database (Denmark)

    Mielby, Jerrik Jørgen; Abildstrøm, Jacob Oskar; Perez-Ferreras, Susana

    2014-01-01

    Mesoporous titanium silicalite-1 (TS-1) prepared by carbon-templating is significantly more active than conventional TS-1 for the oxidation of pyridine derivatives using aqueous hydrogen peroxide as oxidant. The catalytic activity is increased by the system of mesopores that helps to overcome the...

  5. Soft templating strategies for the synthesis of mesoporous materials: inorganic, organic-inorganic hybrid and purely organic solids.

    Science.gov (United States)

    Pal, Nabanita; Bhaumik, Asim

    2013-03-01

    With the discovery of MCM-41 by Mobil researchers in 1992 the journey of the research on mesoporous materials started and in the 21st century this area of scientific investigation have extended into numerous branches, many of which contribute significantly in emerging areas like catalysis, energy, environment and biomedical research. As a consequence thousands of publications came out in large varieties of national and international journals. In this review, we have tried to summarize the published works on various synthetic pathways and formation mechanisms of different mesoporous materials viz. inorganic, organic-inorganic hybrid and purely organic solids via soft templating pathways. Generation of nanoscale porosity in a solid material usually requires participation of organic template (more specifically surfactants and their supramolecular assemblies) called structure-directing agent (SDA) in the bottom-up chemical reaction process. Different techniques employed for the syntheses of inorganic mesoporous solids, like silicas, metal doped silicas, transition and non-transition metal oxides, mixed oxides, metallophosphates, organic-inorganic hybrids as well as purely organic mesoporous materials like carbons, polymers etc. using surfactants are depicted schematically and elaborately in this paper. Moreover, some of the frontline applications of these mesoporous solids, which are directly related to their functionality, composition and surface properties are discussed at the appropriate places. Copyright © 2012 Elsevier B.V. All rights reserved.

  6. Fluorescent Functionalized Mesoporous Silica for Radioactive Material Extraction

    International Nuclear Information System (INIS)

    Li, Juan; Zhu, Kake; Shang, Jianying; Wang, Donghai; Nie, Zimin; Guo, Ruisong; Liu, Chongxuan; Wang, Zheming; Li, Xiaolin; Liu, Jun

    2012-01-01

    Mesoporous silica with covalently bound salicylic acid molecules incorporated in the structure was synthesized with a one-pot, co-condensation reaction at room temperature. The as-synthesized material has a large surface area, uniform particle size, and an ordered pore structure as determined by characterization with transmission electron microscopy, thermal gravimetric analysis, and infrared spectra, etc. Using the strong fluorescence and metal coordination capability of salicylic acid, functionalized mesoporous silica (FMS) was developed to track and extract radionuclide contaminants, such as uranyl (U(VI)) ions encountered in subsurface environments. Adsorption measurements showed a strong affinity of the FMS toward U(VI) with a Kd value of 105 mL/g, which is four orders of magnitude higher than the adsorption of U(VI) onto most of the sediments in natural environments. The new materials have a potential for synergistic environmental monitoring and remediation of the radionuclide U(VI) from contaminated subsurface environments.

  7. 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.

  8. Potential of hybrid functionalized meso-porous materials for the separation and immobilization of radionuclides

    International Nuclear Information System (INIS)

    Luca, V.

    2013-01-01

    Functionalized meso-porous materials are a class of hybrid organic-inorganic material in which a meso-porous metal oxide framework is functionalized with multifunctional organic molecules. These molecules may contain one or more anchor groups that form strong bonds to the pore surfaces of the metal oxide framework and free functional groups that can impart and or modify the functionality of the material such as for binding metal ions in solution. Such materials have been extensively studied over the past decade and are of particular interest in absorption applications because of the tremendous versatility in choosing the composition and architecture of the metal oxide framework and the nature of the functional organic molecule as well as the efficient mass transfer that can occur through a well-designed hierarchically porous network. A sorbent for nuclear applications would have to be highly selective for particular radio nuclides, it would need to be hydrolytically and radiolytically stable, and it would have to possess reasonable capacity and fast kinetics. The sorbent would also have to be available in a form suitable for use in a column. Finally, it would also be desirable if once saturated with radio nuclides, the sorbent could be recycled or converted directly into a ceramic or glass waste form suitable for direct repository disposal or even converted directly into a material that could be used as a transmutation target. Such a cradle-to- grave strategy could have many benefits in so far as process efficiency and the generation of secondary wastes are concerned.This paper will provide an overview of work done on all of the above mentioned aspects of the development of functionalized meso-porous adsorbent materials for the selective separation of lanthanides and actinides and discuss the prospects for future implementation of a cradle-to-grave strategy with such materials. (author)

  9. A review on chemical methodologies for preparation of mesoporous silica and alumina based materials.

    Science.gov (United States)

    Naik, Bhanudas; Ghosh, Narendra Nath

    2009-01-01

    The discovery of novel family of molecular sieves called M41S aroused a worldwide resurgence in the field of porous materials. According to IUPAC definition inorganic solids that contain pores with diameter in the size range of 20-500 A are considered mesoporous materials. Mesoporous silica and alumina based materials find applications in catalysis, adsorption, host- guest encapsulation etc. This article reviews the current state of art and outline the recent patents in mesoporous materials research in three general areas: Synthesis, various mechanisms involved for porous structure formation and applications of silica and alumina based mesoporous materials.

  10. Assessment of surface acidity in mesoporous materials containing aluminum and titanium

    Science.gov (United States)

    Araújo, Rinaldo S.; Maia, Débora A. S.; Azevedo, Diana C. S.; Cavalcante, Célio L., Jr.; Rodríguez-Castellón, E.; Jimenez-Lopez, A.

    2009-04-01

    The surface acidity of mesoporous molecular sieves of aluminum and titanium was evaluated using four different techniques: n-butylamine volumetry, cyclohexylamine thermodesorption, temperature-programmed desorption of ammonia and adsorption of pyridine. The nature, strength and concentration of the acid sites were determined and correlated to the results of a probe reaction of anthracene oxidation to 9,10-anthraquinone (in liquid phase). In general, the surface acidity was highly influenced by the nature, location and coordination of the metal species (Al and Ti) in the mesoporous samples. Moderate to strong Brönsted acid sites were identified for the Al-MCM-41 sample in a large temperature range. For mesoporous materials containing Ti, the acidity was represented by a combination of weak to moderate Brönsted and Lewis acid sites. The Ti-HMS sample exhibits a higher acidity of moderate strength together with a well-balanced concentration of Brönsted and Lewis acid sites, which enhanced both conversion and selectivity in the oxidation reaction of anthracene.

  11. Spectroscopy of photonic band gaps in mesoporous one-dimensional photonic crystals based on aluminum oxide

    International Nuclear Information System (INIS)

    Gorelik, V.S.; Voinov, Yu.P.; Shchavlev, V.V.; Bi, Dongxue; Shang, Guo Liang; Fei, Guang Tao

    2017-01-01

    Mesoporous one-dimensional photonic crystals based on aluminum oxide have been synthesized by electrochemical etching method. Reflection spectra of the obtained mesoporous samples in a wide spectral range that covers several band gaps are presented. Microscopic parameters of photonic crystals are calculated and corresponding reflection spectra for the first six band gaps are presented.

  12. 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.

  13. Mesoporous silica as carrier of antioxidant for food packaging materials

    Science.gov (United States)

    Buonocore, Giovanna Giuliana; Gargiulo, Nicola; Verdolotti, Letizia; Liguori, Barbara; Lavorgna, Marino; Caputo, Domenico

    2014-05-01

    Mesoporous silicas have been long recognized as very promising materials for the preparation of drug delivery systems. In this work SBA-15 mesoporous silica has been functionalized with amino-silane to be used as carrier of antioxidant compound in the preparation of active food packaging materials exhibiting tailored release properties. Active films have been prepared by loading the antioxidant tocopherol, the purely siliceous SBA-15 and the aminofunctionalized SBA-15 loaded with tocopherol into LDPE matrix trough a two-step process (mixing+extrusion). The aim of the present work is the study of the effect of the pore size and of the chemical functionality of the internal walls of the mesophase on the migration of tocopherol from active LDPE polymer films. Moreover, it has been proved that the addition of the active compound do not worsen the properties of the film such as optical characteristic and water vapor permeability, thus leading to the development of a material which could be favorably used mainly, but not exclusively, in the sector of food packaging.

  14. Mesoporous binary metal oxide nanocomposites: Synthesis, characterization and decontamination of sulfur mustard

    Energy Technology Data Exchange (ETDEWEB)

    Praveen Kumar, J., E-mail: praveenjella10@gmail.com; Prasad, G.K.; Ramacharyulu, P.V.R.K.; Singh, Beer; Gopi, T.; Krishna, R.

    2016-04-15

    Mesoporous MnO{sub 2}–ZnO, Fe{sub 2}O{sub 3}–ZnO, NiO–ZnO, and CeO{sub 2}–ZnO binary metal oxide nanocomposites were studied as sorbent decontaminants against sulfur mustard. They were synthesized by precipitation pyrolysis method and characterized by means of transmission electron microscopy, scanning electron microscopy coupled with energy dispersive analysis of X rays, X ray diffraction, and nitrogen adsorption techniques. The transmission electron microscopy and nitrogen adsorption data indicated the presence of pores with diameter ranging from 10 to 70 nm in the binary metal oxide nanocomposites and these materials exhibited surface area values in the range of 76–134 m{sup 2}/g. These binary metal oxide nanocomposites demonstrated large decontamination efficiencies against sulfur mustard when compared to their single component metal oxide nanoparticles. The binary metal oxide nanocomposites effectively decontaminated sulfur mustard into relatively non toxic products such as chloro ethyl vinyl sulfide, divinyl sulfide, 1,4-oxathiane, etc. The promising decontamination properties of binary metal oxide nanocomposites against sulfur mustard were attributed to the basic sites, Lewis acid sites, and the presence of these sites was confirmed by CO{sub 2} and NH{sub 3} temperature programmed desorption. - Graphical abstract: Mesoporous MnO{sub 2}–ZnO, Fe{sub 2}O{sub 3}–ZnO, NiO–ZnO, and CeO{sub 2}–ZnO binary metal oxide nanocomposites were studied as sorbent decontaminants against sulfur mustard. - Highlights: • Binary metal oxide nanocomposites were synthesized by co-precipitation method. • They were studied as sorbent decontaminants against sulfur mustard. • They decontaminated sulfur mustard into non toxic products. • MnO{sub 2}–ZnO and CeO{sub 2}–ZnO nanocomposites showed greater decontamination efficiency.

  15. 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

  16. Polyaniline nanofiber/large mesoporous carbon composites as electrode materials for supercapacitors

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Huan; Xu, Bin; Jia, Mengqiu, E-mail: jiamq@mail.buct.edu.cn; Zhang, Mei; Cao, Bin; Zhao, Xiaonan; Wang, Yu

    2015-03-30

    Highlights: • The composites of polyaniline nanofiber and large mesoporous carbon were prepared for supercapacitors. • The large mesoporous carbons were simply prepared by nano-CaCO{sub 3} template method. • The composites exhibit high capacitance and good rate capability and cycle stability. - Abstract: A composite of polyaniline nanofiber/large mesoporous carbon (PANI-F/LMC) hybrid was prepared by an in situ chemical oxidative polymerization of aniline monomer with nano-CaCO{sub 3} templated LMC as host matrix for supercapacitors. The morphology, composition and electronic structure of the composites (PANI-F/LMC) together with pure PANI nanofibers and the LMC were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), FT-IR, X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). It is found that the PANI nanofibers were incorporated into the large mesochannels of LMC with interpenetrating framework formed. Such unique structure endows the PANI-F/LMC composite with a high capacitance of 473 F g{sup −1} at a current load of 0.1 A g{sup −1} with good rate performance and cycling stability, suggesting its potential application in the electrode material for supercapacitors.

  17. Polyaniline nanofiber/large mesoporous carbon composites as electrode materials for supercapacitors

    International Nuclear Information System (INIS)

    Liu, Huan; Xu, Bin; Jia, Mengqiu; Zhang, Mei; Cao, Bin; Zhao, Xiaonan; Wang, Yu

    2015-01-01

    Highlights: • The composites of polyaniline nanofiber and large mesoporous carbon were prepared for supercapacitors. • The large mesoporous carbons were simply prepared by nano-CaCO 3 template method. • The composites exhibit high capacitance and good rate capability and cycle stability. - Abstract: A composite of polyaniline nanofiber/large mesoporous carbon (PANI-F/LMC) hybrid was prepared by an in situ chemical oxidative polymerization of aniline monomer with nano-CaCO 3 templated LMC as host matrix for supercapacitors. The morphology, composition and electronic structure of the composites (PANI-F/LMC) together with pure PANI nanofibers and the LMC were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), FT-IR, X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). It is found that the PANI nanofibers were incorporated into the large mesochannels of LMC with interpenetrating framework formed. Such unique structure endows the PANI-F/LMC composite with a high capacitance of 473 F g −1 at a current load of 0.1 A g −1 with good rate performance and cycling stability, suggesting its potential application in the electrode material for supercapacitors

  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. 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.

  20. Mesoporous silicon oxide films and their uses as templates in obtaining nanostructured conductive polymers

    Science.gov (United States)

    Salgado, R.; Arteaga, G. C.; Arias, J. M.

    2018-04-01

    Obtaining conductive polymers (CPs) for the manufacture of OLEDs, solar cells, electrochromic devices, sensors, etc., has been possible through the use of electrochemical techniques that allow obtaining films of controlled thickness with positive results in different applications. Current trends point towards the manufacture of nanomaterials, and therefore it is necessary to develop methods that allow obtaining CPs with nanostructured morphology. This is possible by using a porous template to allow the growth of the polymeric materials. However, prior and subsequent treatments are required to separate the material from the template so that it can be evaluated in the applications mentioned above. This is why mesoporous silicon oxide films (template) are essential for the synthesis of nanostructured polymers since both the template and the polymer are obtained on the electrode surface, and therefore it is not necessary to separate the material from the template. Thus, the material can be evaluated directly in the applications mentioned above. The dimensions of the resulting nanostructures will depend on the power, time and technique used for electropolymerization as well as the monomer and the surfactant of the mesoporous film.

  1. 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

  2. Preparation, characterization, and electrochemical application of mesoporous copper oxide

    International Nuclear Information System (INIS)

    Cheng, Liang; Shao, Mingwang; Chen, Dayan; Zhang, Yuzhong

    2010-01-01

    Mesoporous CuO was successfully synthesized via thermal decomposition of CuC 2 O 4 precursors. These products had ring-like morphology, which was made up of nanoparticles with the average diameter of 40 nm. The electrochemical experiments showed that the mesoporous CuO decreased the overvoltage of the electrode and increased electron transference in the measurement of dopamine.

  3. Bi-template assisted synthesis of mesoporous manganese oxide nanostructures: Tuning properties for efficient CO oxidation.

    Science.gov (United States)

    Roy, Mouni; Basak, Somjyoti; Naskar, Milan Kanti

    2016-02-21

    A simple soft bi-templating process was used for the synthesis of mesoporous manganese oxide nanostructures using KMnO4 as a precursor and polyethylene glycol and cetyltrimethylammonium bromide as templates in the presence of benzaldehyde as an organic additive in alkaline media, followed by calcination at 400 °C. X-ray diffraction and Raman spectroscopic analysis of the calcined products confirmed the existence of stoichiometric (MnO2 and Mn5O8) and non-stoichiometric mixed phases (MnO2 + Mn5O8) of Mn oxides obtained by tuning the concentration of the additive and the synthesis time. The surface properties of the prepared Mn oxides were determined by X-ray photoelectron spectroscopy. The mesoporosity of the samples was confirmed by N2 adsorption-desorption. Different synthetic conditions resulted in the formation of different morphologies of the Mn oxides (α-MnO2, Mn5O8, and α-MnO2 + Mn5O8), such as nanoparticles, nanorods, and nanowires. The synthesized mesoporous Mn oxide nanostructures were used for the catalytic oxidation of the harmful air pollutant carbon monoxide. The Mn5O8 nanoparticles with the highest Brunauer-Emmett-Teller surface area and the non-stoichiometric manganese oxide (α-MnO2 + Mn5O8) nanorods with a higher Mn(3+) concentration had the best catalytic efficiency.

  4. 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.

  5. Bridged graphite oxide materials

    Science.gov (United States)

    Herrera-Alonso, Margarita (Inventor); McAllister, Michael J. (Inventor); Aksay, Ilhan A. (Inventor); Prud'homme, Robert K. (Inventor)

    2010-01-01

    Bridged graphite oxide material comprising graphite sheets bridged by at least one diamine bridging group. The bridged graphite oxide material may be incorporated in polymer composites or used in adsorption media.

  6. 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

  7. Hydrothermal synthesis of mesoporous metal oxide arrays with enhanced properties for electrochemical energy storage

    International Nuclear Information System (INIS)

    Xiao, Anguo; Zhou, Shibiao; Zuo, Chenggang; Zhuan, Yongbing; Ding, Xiang

    2015-01-01

    Highlights: • NiO mesoporous nanowall arrays are prepared via hydrothermal method. • Mesoporous nanowall arrays are favorable for fast ion/electron transfer. • NiO mesoporous nanowall arrays show good supercapacitor performance. - Abstract: Mesoporous nanowall NiO arrays are prepared by a facile hydrothermal synthesis method with a following annealing process. The NiO nanowall shows continuous mesopores ranging from 5 to 10 nm and grows vertically on the substrate forming a porous net-like structure with macropores of 20–300 nm. A plausible mechanism is proposed for the growth of mesoporous nanowall NiO arrays. As cathode material of pseudocapacitors, the as-prepared mesoporous nanowall NiO arrays show good pseudocapacitive performances with a high capacitance of 600 F g −1 at 2 A g −1 and impressive high-rate capability with a specific capacitance of 338 F g −1 at 40 A g −1 . In addition, the mesoporous nanowall NiO arrays possess good cycling stability. After 6000 cycles at 2 A g −1 , a high capacitance of 660 F g −1 is attained, and no obvious degradation is observed. The good electrochemical performance is attributed to its highly porous morphology, which provides large reaction surface and short ion diffusion paths, leading to enhanced electrochemical properties

  8. Preparation of mesoporous alumina films by anodization: Effect of pretreatments on the aluminum surface and MTBE catalytic oxidation

    International Nuclear Information System (INIS)

    Vazquez, A.L.; Carrera, R.; Arce, E.; Castillo, N.; Castillo, S.; Moran-Pineda, M.

    2009-01-01

    Mesoporous materials are both scientifically and technologically important because of the presence of voids of controllable dimensions at atomic, molecular, and nanometric scales. Over the last decade, there has been both an increasing interest and research effort in the synthesis and characterization of these types of materials. The purposes of this work are to study the physical and chemical changes in the properties of mesoporous alumina films produced by anodization in sulphuric acid by different pretreatments on the aluminium surface such as mechanical polishing [MP] and electropolishing [EP]; and to compare their properties such as morphology, structure and catalytic activity with those present in commercial alumina. The morphologic and physical characterizations of the alumina film samples were carried out by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The chemical evaluations were performed by the oxidation of methyl-tert-butyl-ether (MTBE) at 400 deg. C under O 2 /He oxidizing conditions (Praxair, 2.0% O 2 /He balance). According to the results, the samples that presented higher activities than those in Al 2 O 3 /Al [MP] and commercial alumina in the MTBE oxidation (69%), were those prepared by Al 2 O 3 /Al [EP]. The average mesoporous diameter was 17 nm, and the morphological shape was equiaxial; thus, that pore distribution was the smallest of all with a homogeneous distribution.

  9. Preparation of mesoporous alumina films by anodization: Effect of pretreatments on the aluminum surface and MTBE catalytic oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Vazquez, A.L., E-mail: avazquezd@ipn.m [Departamento de Ingenieria Metalurgica, ESIQIE-IPN, AP 75-876, Mexico, D.F. (Mexico); Programa de Ingenieria Molecular, Instituto Mexicano del Petroleo, Eje Lazaro Cardenas 152, C.P. 07730, Mexico, D.F. (Mexico); Carrera, R. [Departamento de Ingenieria Metalurgica, ESIQIE-IPN, AP 75-876, Mexico, D.F. (Mexico); Programa de Ingenieria Molecular, Instituto Mexicano del Petroleo, Eje Lazaro Cardenas 152, C.P. 07730, Mexico, D.F. (Mexico); Arce, E. [Departamento de Ingenieria Metalurgica, ESIQIE-IPN, AP 75-876, Mexico, D.F. (Mexico); Castillo, N. [CINVESTAV, Departamento de Fisica. Av. IPN 2508, 07360, Mexico, D.F (Mexico); Castillo, S. [Departamento de Ingenieria Metalurgica, ESIQIE-IPN, AP 75-876, Mexico, D.F. (Mexico); Programa de Ingenieria Molecular, Instituto Mexicano del Petroleo, Eje Lazaro Cardenas 152, C.P. 07730, Mexico, D.F. (Mexico); Moran-Pineda, M. [Programa de Ingenieria Molecular, Instituto Mexicano del Petroleo, Eje Lazaro Cardenas 152, C.P. 07730, Mexico, D.F. (Mexico)

    2009-08-26

    Mesoporous materials are both scientifically and technologically important because of the presence of voids of controllable dimensions at atomic, molecular, and nanometric scales. Over the last decade, there has been both an increasing interest and research effort in the synthesis and characterization of these types of materials. The purposes of this work are to study the physical and chemical changes in the properties of mesoporous alumina films produced by anodization in sulphuric acid by different pretreatments on the aluminium surface such as mechanical polishing [MP] and electropolishing [EP]; and to compare their properties such as morphology, structure and catalytic activity with those present in commercial alumina. The morphologic and physical characterizations of the alumina film samples were carried out by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The chemical evaluations were performed by the oxidation of methyl-tert-butyl-ether (MTBE) at 400 deg. C under O{sub 2}/He oxidizing conditions (Praxair, 2.0% O{sub 2}/He balance). According to the results, the samples that presented higher activities than those in Al{sub 2}O{sub 3}/Al [MP] and commercial alumina in the MTBE oxidation (69%), were those prepared by Al{sub 2}O{sub 3}/Al [EP]. The average mesoporous diameter was 17 nm, and the morphological shape was equiaxial; thus, that pore distribution was the smallest of all with a homogeneous distribution.

  10. Synthesis of Nitrogen-Doped Mesoporous Carbon for the Catalytic Oxidation of Ethylbenzene

    Science.gov (United States)

    Wang, Ruicong; Yu, Yifeng; Zhang, Yue; Lv, Haijun; Chen, Aibing

    2017-06-01

    Nitrogen-doped ordered mesoporous carbon (NOMC) was fabricated via a simple hard-template method by functionalized ionic liquids as carbon and nitrogen source, SBA-15 as a hard-template. The obtained NOMC materials have a high nitrogen content of 5.55 %, a high surface area of 446.2 m2 g-1, and an excellent performance in catalysing oxidation of ethylbenzene. The conversion rate of ethylbenzene can be up to 84.5% and the yield of acetophenone can be up to 69.9%, the results indicated that the NOMC materials have a faster catalytic rate and a higher production of acetophenone than catalyst-free and CMK-3, due to their uniform pore size, high surface area and rich active sites in the carbon pore walls.

  11. Mesoporous amorphous tungsten oxide electrochromic films: a Raman analysis of their good switching behavior

    International Nuclear Information System (INIS)

    Chatzikyriakou, Dafni; Krins, Natacha; Gilbert, Bernard; Colson, Pierre; Dewalque, Jennifer; Denayer, Jessica; Cloots, Rudi; Henrist, Catherine

    2014-01-01

    Graphical abstract: - Highlights: • Mesoporous films exhibit better electrochemical kinetics compared to the dense films. • Mesoporous films exhibit better reversibility compared to the dense films. • Li + cations disrupt WO 3 network in a reversible way in the mesoporous film. • Li + irreversibly intercalate in the voids of crystallites in the dense film. - Abstract: The intercalation and de-intercalation of lithium cations in electrochromic tungsten oxide thin films are significantly influenced by their structural and surface characteristics. In this study, we prepared two types of amorphous films via the sol-gel technique: one dense and one mesoporous in order to compare their response upon lithium intercalation and de-intercalation. According to chronoamperometric measurements, Li + intercalates/de-intercalates faster in the mesoporous film (24s/6s) than in the dense film (48s/10s). The electrochemical measurements (cyclic voltammetry and chronoamperometry) also showed worse reversibility for the dense film compared to the mesoporous film, giving rise to important Li + trapping and remaining coloration of the film. Raman analysis showed that the mesoporous film provides more accessible and various W-O surface bonds for Li + intercalation. On the contrary, in the first electrochemical insertion and de-insertion in the dense film, Li + selectively reacts with a few surface W-O bonds and preferentially intercalates into pre-existing crystallites to form stable irreversible Li x WO 3 bronze

  12. A tri-continuous mesoporous material with a silica pore wall following a hexagonal minimal surface

    KAUST Repository

    Han, Yu

    2009-04-06

    Ordered porous materials with unique pore structures and pore sizes in the mesoporous range (2-50nm) have many applications in catalysis, separation and drug delivery. Extensive research has resulted in mesoporous materials with one-dimensional, cage-like and bi-continuous pore structures. Three families of bi-continuous mesoporous materials have been made, with two interwoven but unconnected channels, corresponding to the liquid crystal phases used as templates. Here we report a three-dimensional hexagonal mesoporous silica, IBN-9, with a tri-continuous pore structure that is synthesized using a specially designed cationic surfactant template. IBN-9 consists of three identical continuous interpenetrating channels, which are separated by a silica wall that follows a hexagonal minimal surface. Such a tri-continuous mesostructure was predicted mathematically, but until now has not been observed in real materials. © 2009 Macmillan Publishers Limited. All rights reserved.

  13. A tri-continuous mesoporous material with a silica pore wall following a hexagonal minimal surface

    KAUST Repository

    Han, Yu; Zhang, Daliang; Chng, Leng Leng; Sun, Junliang; Zhao, L. J.; Zou, Xiaodong; Ying, Jackie

    2009-01-01

    Ordered porous materials with unique pore structures and pore sizes in the mesoporous range (2-50nm) have many applications in catalysis, separation and drug delivery. Extensive research has resulted in mesoporous materials with one-dimensional, cage-like and bi-continuous pore structures. Three families of bi-continuous mesoporous materials have been made, with two interwoven but unconnected channels, corresponding to the liquid crystal phases used as templates. Here we report a three-dimensional hexagonal mesoporous silica, IBN-9, with a tri-continuous pore structure that is synthesized using a specially designed cationic surfactant template. IBN-9 consists of three identical continuous interpenetrating channels, which are separated by a silica wall that follows a hexagonal minimal surface. Such a tri-continuous mesostructure was predicted mathematically, but until now has not been observed in real materials. © 2009 Macmillan Publishers Limited. All rights reserved.

  14. Synthesis and characterization of a mesoporous hydrous zirconium oxide used for arsenic removal from drinking water

    International Nuclear Information System (INIS)

    Bortun, Anatoly; Bortun, Mila; Pardini, James; Khainakov, Sergei A.; Garcia, Jose R.

    2010-01-01

    Powder (20-50 μm) mesoporous hydrous zirconium oxide was prepared from a zirconium salt granular precursor. The effect of some process parameters on product morphology, porous structure and adsorption performance has been studied. The use of hydrous zirconium oxide for selective arsenic removal from drinking water is discussed.

  15. Investigation of Room Temperature Synthesis of Titanium Dioxide Nanoclusters Dispersed on Cubic MCM-48 Mesoporous Materials

    OpenAIRE

    Sridhar Budhi; Chia-Ming Wu; Dan Zhao; Ranjit T. Koodali

    2015-01-01

    Titania containing cubic MCM-48 mesoporous materials were synthesized successfully at room temperature by a modified Stöber method. The integrity of the cubic mesoporous phase was retained even at relatively high loadings of titania. The TiO2-MCM-48 materials were extensively characterized by a variety of physico-chemical techniques. The physico-chemical characterization indicate that Ti4+ ions can be substituted in framework tetrahedral positions. The relative amount of Ti4+ ions in tetrahe...

  16. Fenton detemplation of ordered (meso)porous materials

    NARCIS (Netherlands)

    Melian-Cabrera, I.; Osman, A. H.; van Eck, E. R. H.; Kentgens, Arno P.M.; Polushkin, E.; Kapteijn, F.; Moulijn, J. A.; Xu, R; Gao, Z; Chen, J; Yan, W

    2007-01-01

    This article describes a new methodology (Fenton detemplation), which consists of removing the template by chemical oxidation and develop the material's porosity. The oxidizing agents are OH radicals, which are generated from H(2)O(2) in the presence of catalytic amounts of Fe cations. This is known

  17. Confine sulfur in mesoporous metal–organic framework @ reduced graphene oxide for lithium sulfur battery

    International Nuclear Information System (INIS)

    Bao, Weizhai; Zhang, Zhian; Qu, Yaohui; Zhou, Chengkun; Wang, Xiwen; Li, Jie

    2014-01-01

    Highlights: • Metal organic framework @ reduced graphene oxide was applied for sulfur cathode. • MIL-101(Cr)@rGO/S composites are synthesized by a facile two-step liquid method. • Cycling stability of MIL-101(Cr)@rGO/S sulfur cathode was improved. -- Abstract: Mesoporous metal organic framework @ reduced graphene oxide (MIL-101(Cr)@rGO) materials have been used as a host material to prepare the multi-composite sulfur cathode through a facile and effective two-step liquid phase method successfully, which is different from the simple MIL-101(Cr)/S mixed preparation method. The successful reduced graphene oxide coating in the MIL-101(Cr)@rGO improve the electronic conductivity of meso-MOFs effectively. The discharge capacity and capacity retention rate of MIL-101(Cr)@rGO/S composite sulfur cathode are as high as 650 mAh g −1 and 66.6% at the 50th cycle at the current density of 335 mA g −1 . While the discharge capacity and capacity retention rate of MIL-101(Cr)/S mixed sulfur cathode is 458 mAh g −1 and 37.3%. Test results indicate that the MIL-101(Cr)@rGO is a promising host material for the sulfur cathode in the lithium–sulfur battery applications

  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. Facile synthesis of graphene oxide @ mesoporous carbon hybrid nanocomposites for lithium sulfur battery

    International Nuclear Information System (INIS)

    Bao, Weizhai; Zhang, Zhian; Chen, Wei; Zhou, Chengkun; Lai, Yanqing; Li, Jie

    2014-01-01

    Graphical abstract: - Highlights: • A novel design and synthesis of GO@Meso-C using GO@MOF-5 as precursor. • GO@Meso-C hybrid material as a host material was applied for sulfur cathode. • Electrochemical performances were improved in sulfur cathode using Go@Meso-C. - Abstract: We present a design and synthesis of a hierarchical architecture of graphene oxide @ mesoporous carbon (GO@Meso-C) using graphene oxide @ metal-organic framework hybrid materials (GO@MOF-5) as both the template and precursor. Active sulfur is encapsulated into the GO@Meso-C matrix prepared via carbonize GO@MOF-5 polyhedrons for high performance lithium sulfur battery. The initial and 100th cycle discharge capacity of GO@Meso-C/S sulfur cathode are as high as 1122 mAh g −1 and 820 mAh g −1 at a current rate of 0.2 C. The remarkably high special capacity and capacity retention rate indicate that the GO@Meso-C is a promising host material for the sulfur cathode in the lithium sulfur battery applications

  20. 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.

  1. Functionalization of mesoporous materials for lanthanide and actinide extraction.

    Science.gov (United States)

    Florek, Justyna; Giret, Simon; Juère, Estelle; Larivière, Dominic; Kleitz, Freddy

    2016-10-14

    Among the energy sources currently available that could address our insatiable appetite for energy and minimize our CO2 emission, solar, wind, and nuclear energy currently occupy an increasing portion of our energy portfolio. The energy associated with these sources can however only be harnessed after mineral resources containing valuable constituents such as actinides (Ac) and rare earth elements (REEs) are extracted, purified and transformed into components necessary for the conversion of energy into electricity. Unfortunately, the environmental impacts resulting from their manufacture including the generation of undesirable and, sometimes, radioactive wastes and the non-renewable nature of the mineral resources, to name a few, have emerged as challenges that should be addressed by the scientific community. In this perspective, the recent development of functionalized solid materials dedicated to selective elemental separation/pre-concentration could provide answers to several of the above-mentioned challenges. This review focuses on recent advances in the field of mesoporous solid-phase (SP) sorbents designed for REEs and Ac liquid-solid extraction. Particular attention will be devoted to silica and carbon sorbents functionalized with commonly known ligands, such as phosphorus or amide-containing functionalities. The extraction performances of these new systems are discussed in terms of sorption capacity and selectivity. In order to support potential industrial applications of the silica and carbon-based sorbents, their main drawbacks and advantages are highlighted and discussed.

  2. Recent progress in mesoporous titania materials: adjusting morphology for innovative applications

    Directory of Open Access Journals (Sweden)

    Juan L Vivero-Escoto, Ya-Dong Chiang, Kevin C-W Wu and Yusuke Yamauchi

    2012-01-01

    Full Text Available This review article summarizes recent developments in mesoporous titania materials, particularly in the fields of morphology control and applications. We first briefly introduce the history of mesoporous titania materials and then review several synthesis approaches. Currently, mesoporous titania nanoparticles (MTNs have attracted much attention in various fields, such as medicine, catalysis, separation and optics. Compared with bulk mesoporous titania materials, which are above a micrometer in size, nanometer-sized MTNs have additional properties, such as fast mass transport, strong adhesion to substrates and good dispersion in solution. However, it has generally been known that the successful synthesis of MTNs is very difficult owing to the rapid hydrolysis of titanium-containing precursors and the crystallization of titania upon thermal treatment. Finally, we review four emerging fields including photocatalysis, photovoltaic devices, sensing and biomedical applications of mesoporous titania materials. Because of its high surface area, controlled porous structure, suitable morphology and semiconducting behavior, mesoporous titania is expected to be used in innovative applications.

  3. Metalloporphyrins immobilized in Fe3O4@SiO2 mesoporous submicrospheres: Reusable biomimetic catalysts for hydrocarbon oxidation.

    Science.gov (United States)

    Barbosa, Isaltino A; de Sousa Filho, Paulo C; da Silva, Douglas L; Zanardi, Fabrício B; Zanatta, Lucas D; de Oliveira, Adilson J A; Serra, Osvaldo A; Iamamoto, Yassuko

    2016-05-01

    We successfully immobilized metalloporphyrins (MeP) in mesoporous silica coating magnetite spheres. In this sense, we prepared two different classes of core@shell supports, which comprise aligned (Fe3O4-AM-MeP, MeP=FeP or MnP) and non-aligned (Fe3O4-NM-MeP, MeP=FeP or MnP) mesoporous magnetic structures. X-ray diffractometry and energy dispersive X-ray spectroscopy confirmed the mesoporous nature of the silica shell of the materials. Magnetization measurements, scanning and transmission electron microscopies (SEM/TEM), electrophoretic mobility (ζ-potential), and infrared spectroscopy (FTIR) also confirm the composition and structure of the materials. The catalysts maintained their catalytic activity during nine reaction cycles toward hydrocarbon oxidation processes without detectable catalyst leaching. The catalysis results revealed a biomimetic pattern of cytochrome P450-type enzymes, thus confirming that the prepared materials are can effectively mimic the activity of such groups. Copyright © 2016 Elsevier Inc. All rights reserved.

  4. Polyaniline nanofiber/large mesoporous carbon composites as electrode materials for supercapacitors

    Science.gov (United States)

    Liu, Huan; Xu, Bin; Jia, Mengqiu; Zhang, Mei; Cao, Bin; Zhao, Xiaonan; Wang, Yu

    2015-03-01

    A composite of polyaniline nanofiber/large mesoporous carbon (PANI-F/LMC) hybrid was prepared by an in situ chemical oxidative polymerization of aniline monomer with nano-CaCO3 templated LMC as host matrix for supercapacitors. The morphology, composition and electronic structure of the composites (PANI-F/LMC) together with pure PANI nanofibers and the LMC were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), FT-IR, X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). It is found that the PANI nanofibers were incorporated into the large mesochannels of LMC with interpenetrating framework formed. Such unique structure endows the PANI-F/LMC composite with a high capacitance of 473 F g-1 at a current load of 0.1 A g-1 with good rate performance and cycling stability, suggesting its potential application in the electrode material for supercapacitors.

  5. A controlled release of ibuprofen by systematically tailoring the morphology of mesoporous silica materials

    International Nuclear Information System (INIS)

    Qu Fengyu; Zhu Guangshan; Lin Huiming; Zhang Weiwei; Sun Jinyu; Li Shougui; Qiu Shilun

    2006-01-01

    A series of mesoporous silica materials with similar pore sizes, different morphologies and variable pore geometries were prepared systematically. In order to control drug release, ibuprofen was employed as a model drug and the influence of morphology and pore geometry of mesoporous silica on drug release profiles was extensively studied. The mesoporous silica and drug-loaded samples were characterized by X-ray diffraction, Fourier transform IR spectroscopy, N 2 adsorption and desorption, scanning electron microscopy, and transmission electron microscopy. It was found that the drug-loading amount was directly correlated to the Brunauer-Emmett-Teller surface area, pore geometry, and pore volume; while the drug release profiles could be controlled by tailoring the morphologies of mesoporous silica carriers. - Graphical abstract: The release of ibuprofen is controlled by tailoring the morphologies of mesoporous silica. The mesoporous silica and drug-loaded samples are characterized by powder X-ray diffraction, Fourier transform IR spectroscopy, N 2 adsorption and desorption, scanning electron microscopy, and transmission electron microscopy. The drug-loading amount is directly correlated to the Brunauer-Emmett-Teller surface area, pore geometry, and pore volume; while the drug release profiles can be controlled by tailoring the morphologies of mesoporous silica carriers

  6. Utilization of a by-product produced from oxidative desulfurization process over Cs-mesoporous silica catalysts.

    Science.gov (United States)

    Kim, Hyeonjoo; Jeong, Kwang-Eun; Jeong, Soon-Yong; Park, Young-Kwon; Kim, Do Heui; Jeon, Jong-Ki

    2011-02-01

    We investigated the use of Cs-mesoporous silica catalysts to upgrade a by-product of oxidative desulfurization (ODS). Cs-mesoporous silica catalysts were characterized through N2 adsorption, XRD, CO2-temperature-programmed desorption, and XRF. Cs-mesoporous silica prepared by the direct incorporation method showed higher catalytic performance than a Cs/MCM-41 catalyst by impregnation method for the catalytic decomposition of sulfone compounds produced from ODS process.

  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. Vanadium-substituted heteropolyacids immobilized on amine- functionalized mesoporous MCM-41: A recyclable catalyst for selective oxidation of alcohols with H2O2

    International Nuclear Information System (INIS)

    Dong, Xinbo; Wang, Danjun; Li, Kebin; Zhen, Yanzhong; Hu, Huaiming; Xue, Ganglin

    2014-01-01

    Graphical abstract: Vanadium-substituted phosphotungstic acids are immobilized on amine- functionalized mesoporous MCM-41 and the hybrid catalyst is proved to be a highly efficient solid catalyst for the oxidation of aromatic alcohols to the corresponding carbonyl compounds with H 2 O 2 , featured by the high conversion and selectivity, easy recovery, and quite steady reuse. - Highlights: • Vanadium-substituted phosphotungstic acid immobilized on amine-functionalized mesoporous MCM-41 are prepared. • HPAs were fixed on the inner surface of mesoporous MCM-41 by chemical bonding to aminosilane groups. • The hybrid catalyst showed much higher catalytic activity than the pure HPAs. • The hybrid catalyst is a highly efficient recyclable solid catalyst for the selective oxidation of aromatic alcohols. - Abstract: New hybrid materials of vanadium-substituted phosphotungstic acids (VHPW) immobilized on amine-functionalized mesoporous MCM-41 (VHPW/MCM-41/NH 2 ) are prepared and characterized by FT-IR, XRD, N 2 adsorption, elemental analysis, SEM and TEM for their structural integrity and physicochemical properties. It is found that the structure of the heteropolyacids is retained upon immobilization over mesoporous materials. The catalytic activities of these hybrid materials are tested in the selective oxidation of alcohols to the carbonyl products with 30% aqueous H 2 O 2 as oxidant in toluene. The catalytic activities of different number of vanadium-substituted phosphotungstic acid are investigated, and among the catalysts, H 5 [PV 2 W 10 O 40 ] immobilized on amine-functionalized MCM-41 exhibits the highest activity with 97% conversion and 99% selectivity in the oxidation of benzyl alcohol to benzaldehyde. The hybrid catalyst is proved to be a highly efficient recyclable solid catalyst for the selective oxidation of aromatic alcohols to the corresponding aldehydes with H 2 O 2

  9. Vanadium-substituted heteropolyacids immobilized on amine- functionalized mesoporous MCM-41: A recyclable catalyst for selective oxidation of alcohols with H{sub 2}O{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Dong, Xinbo [Key Laboratory of Synthetic and Natural Functional Molecule Chemistry, Department of Chemistry (Ministry of Education), Northwest University, Xi' an 710069 (China); Wang, Danjun [Key Laboratory of Synthetic and Natural Functional Molecule Chemistry, Department of Chemistry (Ministry of Education), Northwest University, Xi' an 710069 (China); College of Chemistry Chemical Engineering, Yanan University, Shaanxi Key Laboratory of Chemical Reaction Engineering, Yan' an 716000 (China); Li, Kebin [Key Laboratory of Synthetic and Natural Functional Molecule Chemistry, Department of Chemistry (Ministry of Education), Northwest University, Xi' an 710069 (China); Zhen, Yanzhong [Key Laboratory of Synthetic and Natural Functional Molecule Chemistry, Department of Chemistry (Ministry of Education), Northwest University, Xi' an 710069 (China); College of Chemistry Chemical Engineering, Yanan University, Shaanxi Key Laboratory of Chemical Reaction Engineering, Yan' an 716000 (China); Hu, Huaiming [Key Laboratory of Synthetic and Natural Functional Molecule Chemistry, Department of Chemistry (Ministry of Education), Northwest University, Xi' an 710069 (China); Xue, Ganglin, E-mail: xglin707@163.com [Key Laboratory of Synthetic and Natural Functional Molecule Chemistry, Department of Chemistry (Ministry of Education), Northwest University, Xi' an 710069 (China)

    2014-09-15

    Graphical abstract: Vanadium-substituted phosphotungstic acids are immobilized on amine- functionalized mesoporous MCM-41 and the hybrid catalyst is proved to be a highly efficient solid catalyst for the oxidation of aromatic alcohols to the corresponding carbonyl compounds with H{sub 2}O{sub 2}, featured by the high conversion and selectivity, easy recovery, and quite steady reuse. - Highlights: • Vanadium-substituted phosphotungstic acid immobilized on amine-functionalized mesoporous MCM-41 are prepared. • HPAs were fixed on the inner surface of mesoporous MCM-41 by chemical bonding to aminosilane groups. • The hybrid catalyst showed much higher catalytic activity than the pure HPAs. • The hybrid catalyst is a highly efficient recyclable solid catalyst for the selective oxidation of aromatic alcohols. - Abstract: New hybrid materials of vanadium-substituted phosphotungstic acids (VHPW) immobilized on amine-functionalized mesoporous MCM-41 (VHPW/MCM-41/NH{sub 2}) are prepared and characterized by FT-IR, XRD, N{sub 2} adsorption, elemental analysis, SEM and TEM for their structural integrity and physicochemical properties. It is found that the structure of the heteropolyacids is retained upon immobilization over mesoporous materials. The catalytic activities of these hybrid materials are tested in the selective oxidation of alcohols to the carbonyl products with 30% aqueous H{sub 2}O{sub 2} as oxidant in toluene. The catalytic activities of different number of vanadium-substituted phosphotungstic acid are investigated, and among the catalysts, H{sub 5}[PV{sub 2}W{sub 10}O{sub 40}] immobilized on amine-functionalized MCM-41 exhibits the highest activity with 97% conversion and 99% selectivity in the oxidation of benzyl alcohol to benzaldehyde. The hybrid catalyst is proved to be a highly efficient recyclable solid catalyst for the selective oxidation of aromatic alcohols to the corresponding aldehydes with H{sub 2}O{sub 2}.

  10. N, P-codoped Mesoporous Carbon Supported PtCox Nanoparticles and Their Superior Electrochemical toward Methanol Oxidation

    Science.gov (United States)

    Cui, Hangjun; Li, Yueming; Liu, Shimin

    2018-03-01

    In this report, a novel strategy by using the N, P co-doped mesoporous carbon structure as catalyst support to enhance the electrochemical catalytic activity of Pt-based catalysts is proposed. The as-synthesized PtCox@N, P-doped mesoporous carbon nanocomposties have been studied as an anode catalyst toward methanol oxidation, exhibiting greatly improved electrochemical activity and stability compared with Pt@mesoporous carbon. The synergistic effects of N, P dual-doping and porous carbon structure help to achieve better electron transport at the electrode surface, which eventually leads to greatly enhanced catalytic activity compared to the pristine Pt/mesoporous carbon.…

  11. Study of vanadium based mesoporous silicas for oxidative dehydrogenation of propane and n-butane

    Czech Academy of Sciences Publication Activity Database

    Bulánek, R.; Kalužová, A.; Setnička, M.; Zukal, Arnošt; Čičmanec, P.; Mayerová, Jana

    2012-01-01

    Roč. 179, č. 1 (2012), s. 149-158 ISSN 0920-5861 R&D Projects: GA ČR GAP106/10/0196 Institutional research plan: CEZ:AV0Z40400503 Keywords : vanadium * oxidative dehydrogenation * mesoporous silicas Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.980, year: 2012

  12. Mesoporous Pt and Pt/Ru alloy electrocatalysts for methanol oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Franceschini, Esteban A. [Grupo de Celdas de Combustible, Departamento de Fisica de la Materia Condensada, Centro Atomico Constituyentes, CNEA. Av. General Paz 1499 (1650), San Martin, Buenos Aires (Argentina); Planes, Gabriel A. [Departamento de Quimica, Facultad de Ciencias Exactas, Fisicoquimicas y Naturales, Universidad Nacional de Rio Cuarto, Agencia Postal No 3, 5800, Rio Cuarto (Argentina); Williams, Federico J. [Departamento de Quimica Inorganica, Analitica y Quimica-Fisica, INQUIMAE CONICET, Facultad Ciencias Exactas y Naturales, Pabellon 2, Ciudad Universitaria, Buenos Aires (Argentina); Soler-Illia, Galo J.A.A. [Gerencia de Quimica, Centro Atomico Constituyentes, CNEA. Av. General Paz 1499 (1650), San Martin, Buenos Aires (Argentina); Corti, Horacio R. [Grupo de Celdas de Combustible, Departamento de Fisica de la Materia Condensada, Centro Atomico Constituyentes, CNEA. Av. General Paz 1499 (1650), San Martin, Buenos Aires (Argentina); Departamento de Quimica Inorganica, Analitica y Quimica-Fisica, INQUIMAE CONICET, Facultad Ciencias Exactas y Naturales, Pabellon 2, Ciudad Universitaria, Buenos Aires (Argentina)

    2011-02-15

    Mesoporous Pt and Pt/Ru catalysts with 2D-hexagonal mesostructure were synthesized using a triblock poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide) copolymer (Pluronic F127 {sup registered}) template, on a gold support. Large electrochemical surface areas were observed for the catalysts prepared at high overpotentials. Compared to the Pt catalyst, the Pt/Ru alloy containing 3 at% of Ru exhibited lower onset potential and more than three times the limit mass activity for methanol oxidation. This behavior is assigned to the larger pore size of the mesoporous Pt and Pt/Ru catalysts obtained with this template that seems to improve the methanol accessibility to the active sites compared to those obtained using lyotropic liquid crystals. (author)

  13. 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

  14. A general approach to mesoporous metal oxide microspheres loaded with noble metal nanoparticles

    KAUST Repository

    Jin, Zhao; Xiao, Manda; Bao, Zhihong; Wang, Peng; Wang, Jianfang

    2012-01-01

    Catalytic microspheres: A general approach is demonstrated for the facile preparation of mesoporous metal oxide microspheres loaded with noble metal nanoparticles (see TEM image in the picture). Among 18 oxide/noble metal catalysts, TiO 2/0.1 mol Pd microspheres showed the highest turnover frequency in NaBH 4 reduction of 4-nitrophenol (see picture). Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. A general approach to mesoporous metal oxide microspheres loaded with noble metal nanoparticles

    KAUST Repository

    Jin, Zhao

    2012-04-26

    Catalytic microspheres: A general approach is demonstrated for the facile preparation of mesoporous metal oxide microspheres loaded with noble metal nanoparticles (see TEM image in the picture). Among 18 oxide/noble metal catalysts, TiO 2/0.1 mol Pd microspheres showed the highest turnover frequency in NaBH 4 reduction of 4-nitrophenol (see picture). Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. 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.

  17. 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.

  18. Mesoporous material grafted with luminescent molecules for the design of selective metal ion chemosensor

    International Nuclear Information System (INIS)

    Zhang Huidong; Zhang Ping; Ye Kaiqi; Sun Yinghui; Jiang Shimei; Wang Yue; Pang Wenqin

    2006-01-01

    Luminescent Schiff-base groups have been successfully grafted on the surface of mesoporous material MCM-48. The grafted Schiff-base groups were employed to prepare luminescent Schiff-base-Zn complex that was covalently bound to the MCM-48 surface. These luminescent mesoporous materials were characterized with X-ray, UV-VIS and emission spectroscopic methods. Experimental results demonstrated that MCM-48 modified with functional groups exhibited novel luminescent property. The chemosensing property of modified MCM-48 sample was investigated. It was demonstrated that the fluorescence of MCM-48 solid with Schiff-base groups could be completely quenched by Cu 2+ cation and this mesoporous material was suitable for sensing Cu 2+ cation in aqueous media

  19. Facile route for synthesis of mesoporous Cr2O3 sheet as anode materials for Li-ion batteries

    International Nuclear Information System (INIS)

    Cao, Zhiqin; Qin, Mingli; Jia, Baorui; Zhang, Lin; Wan, Qi; Wang, Mingshan; Volinsky, Alex A.; Qu, Xuanhui

    2014-01-01

    Mesoporous Cr 2 O 3 with a high specific surface area of 162 m 2 g −1 is prepared by the solution combustion method. The mesoporous Cr 2 O 3 has a sheet structure, which consists of nanoparticles with an average size of 20 nm. As an anode electrode material for rechargeable lithium-ion batteries, the mesoporous Cr 2 O 3 nanoparticles display enhanced electrochemical performance. Stable and reversible capacity of 480 mA h g −1 after 55 cycles is demonstrated. The enhanced electrochemical performance of the Cr 2 O 3 can be attributed to the high surface area and morphological characteristics of mesoporous materials

  20. Structural and Quantitative Investigation of Perovskite Pore Filling in Mesoporous Metal Oxides

    Directory of Open Access Journals (Sweden)

    Shany Gamliel

    2016-11-01

    Full Text Available In recent years, hybrid organic–inorganic perovskite light absorbers have attracted much attention in the field of solar cells due to their optoelectronic characteristics that enable high power conversion efficiencies. Perovskite-based solar cells’ efficiency has increased dramatically from 3.8% to more than 20% in just a few years, making them a promising low-cost alternative for photovoltaic applications. The deposition of perovskite into a mesoporous metal oxide is an influential factor affecting solar cell performance. Full coverage and pore filling into the porous metal oxide are important issues in the fabrication of highly-efficient mesoporous perovskite solar cells. In this work, we carry out a structural and quantitative investigation of CH3NH3PbI3 pore filling deposited via sequential two-step deposition into two different mesoporous metal oxides—TiO2 and Al2O3. We avoid using a hole conductor in the perovskite solar cells studied in this work to eliminate undesirable end results. Filling oxide pores with perovskite was characterized by Energy Dispersive X-ray Spectroscopy (EDS in Transmission Electron Microscopy (TEM on cross-sectional focused ion beam (FIB lamellae. Complete pore filling of CH3NH3PbI3 perovskite into the metal oxide pores was observed down to X-depth, showing the presence of Pb and I inside the pores. The observations reported in this work are particularly important for mesoporous Al2O3 perovskite solar cells, as pore filling is essential for the operation of this solar cell structure. This work presents structural and quantitative proof of complete pore filling into mesoporous perovskite-based solar cells, substantiating their high power conversion efficiency.

  1. Mesoporous TiO2 : an alternative material for PEM fuel cells catalyst support

    Energy Technology Data Exchange (ETDEWEB)

    Do, T.B. [Michigan Univ., Ann Arbor, MI (United States). Dept. of Materials Science; Ruthkosky, M.; Cai, M. [General Motors, Warren, MI (United States). Research and Development Center

    2008-07-01

    This paper discussed the feasibility of using an alternative catalyst support material to replace carbon in proton exchange membrane (PEM) fuel cells. The alternative catalyst support material requires a high surface area with a large porosity but must have comparable conductivity with carbon. A mesoporous titanium oxide (TiO2) material produced by coprecipitation was introduced. The conductivity of the material is about one order of that of carbon. The 8 mole per cent Nb-doped TiO2 was formed and deposited on the surface of a nano polystyrene (PS) template via the hydrolysis of a co-solution of Ti(OC4H9)4 and Nb(OC2H5)5. The removal of PS by heat treatment produced porous structure of TiO2 with the appearance of 3 different pore types, notably open pore, ink-pot pores and closed pores. TiO2 formed from the rutile phase, allowing a lower activation temperature at 850 degrees C in a hydrogen atmosphere. The pore structures were retained after this heat treatment. The BET surface area was 116 m{sup 2}/g, porosity was 22 per cent and the average pore size was 159 angstrom. The conductivity improved considerably from almost non-conductive to one order of that of carbon.

  2. Unexpected nitrile formation in bio-based mesoporous materials (Starbons®).

    Science.gov (United States)

    Attard, Jennifer; Milescu, Roxana; Budarin, Vitaliy; Matharu, Avtar S; Clark, James H

    2018-01-16

    The bio-based mesoporous materials made from polysaccharides, Starbons® can be modified by two different routes to give high levels of N-content, unexpectedly including significant quantities of nitrile groups which can improve the materials performance in applications including metal capture.

  3. 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.

  4. Formation of Micro and Mesoporous Amorphous Silica-Based Materials from Single Source Precursors

    Directory of Open Access Journals (Sweden)

    Mohd Nazri Mohd Sokri

    2016-03-01

    Full Text Available Polysilazanes functionalized with alkoxy groups were designed and synthesized as single source precursors for fabrication of micro and mesoporous amorphous silica-based materials. The pyrolytic behaviors during the polymer to ceramic conversion were studied by the simultaneous thermogravimetry-mass spectrometry (TG-MS analysis. The porosity of the resulting ceramics was characterized by the N2 adsorption/desorption isotherm measurements. The Fourier transform infrared spectroscopy (FT-IR and Raman spectroscopic analyses as well as elemental composition analysis were performed on the polymer-derived amorphous silica-based materials, and the role of the alkoxy group as a sacrificial template for the micro and mesopore formations was discussed from a viewpoint to establish novel micro and mesoporous structure controlling technologies through the polymer-derived ceramics (PDCs route.

  5. 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.

  6. Mesoporous MFe{sub 2}O{sub 4} (M = Mn, Co, and Ni) for anode materials of lithium-ion batteries: Synthesis and electrochemical properties

    Energy Technology Data Exchange (ETDEWEB)

    Duan, Lianfeng, E-mail: duanlf@mail.ccut.edu.cn [State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Key Laboratory of Advanced Structural Materials, Ministry of Education, and Department of Materials Science and Engineering, Changchun University of Technology, Changchun 130012 (China); Wang, Yuanxin; Wang, Linan [Key Laboratory of Advanced Structural Materials, Ministry of Education, and Department of Materials Science and Engineering, Changchun University of Technology, Changchun 130012 (China); Zhang, Feifei [State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Wang, Limin [State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China)

    2015-01-15

    Highlights: • MFe{sub 2}O{sub 4} (M = Mn, Co, and Ni) are synthesized by a template-free hydrothermal method. • The mesoporous morphology is formed by self-assembly of crystal nucleus. • The mesporous MnFe{sub 2}O{sub 4} have the active phase and the synergy for Li-ion storage. - Abstract: The MFe{sub 2}O{sub 4} (M = Mn, Co, and Ni) mesoporous spheres with an average diameter of 250 nm were synthesized through a template-free hydrothermal method. The mesoporous MnFe{sub 2}O{sub 4} with a large surface area of 87.5 m{sup 2}/g and an average pore size of 27.52 nm were obtained. As the anode materials for Li-ion batteries, the mesoporous MnFe{sub 2}O{sub 4} exhibits excellent initial charge and discharge capacities of 1010 and 642.5 mA h/g. After 50 cycles, the discharge capacity could still remain at 379 mA h/g. The results showed that the active phase and the synergy between different metal oxides greatly improved the electrochemical performance, and the mesoporous composite could stabilize the structure of the electrodes.

  7. Importance of Micropore-Mesopore Interfaces in Carbon Dioxide Capture by Carbon-Based Materials.

    Science.gov (United States)

    Durá, Gema; Budarin, Vitaliy L; Castro-Osma, José A; Shuttleworth, Peter S; Quek, Sophie C Z; Clark, James H; North, Michael

    2016-08-01

    Mesoporous carbonaceous materials (Starbons®) derived from low-value/waste bio-resources separate CO2 from CO2 /N2 mixtures. Compared to Norit activated charcoal (AC), Starbons® have much lower microporosities (8-32 % versus 73 %) yet adsorb up to 65 % more CO2 . The presence of interconnected micropores and mesopores is responsible for the enhanced CO2 adsorption. The Starbons® also showed three-four times higher selectivity for CO2 adsorption rather than N2 adsorption compared to AC. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Carbon-coated mesoporous SnO2 nanospheres as anode material for lithium ion batteries

    International Nuclear Information System (INIS)

    Wang, Fei; Song, Xiaoping; Yao, Gang; Zhao, Mingshu; Liu, Rui; Xu, Minwei; Sun, Zhanbo

    2012-01-01

    In this paper mesoporous SnO 2 nanospheres with an average diameter of about 83 nm, composed of many tiny primary particles (∼10 nm) and holes, are synthesized on a large scale by a simple hydrothermal route. The as-prepared mesoporous SnO 2 nanospheres were uniformly coated with carbon by a further hydrothermal treatment in glucose aqueous solution. As anode materials for lithium-ion batteries, the core–shell SnO 2 /C nanocomposites exhibit a markedly improved cycling performance.

  9. Comparison of oxidation properties of Nb and Sn in mesoporous molecular sieves

    Czech Academy of Sciences Publication Activity Database

    Nowak, I.; Feliczak, A.; Nekoksová, Iveta; Čejka, Jiří

    2007-01-01

    Roč. 321, č. 1 (2007), s. 40-48 ISSN 0926-860X R&D Projects: GA MPO FT-TA/040; GA AV ČR 1ET400400413 Grant - others:Ministry of Scientific Research and Information Technology(PL) N204 084 31/1965 Institutional research plan: CEZ:AV0Z40400503 Keywords : mesoporous molecular sieves * niobium * tin * synthesis * oxidation properties Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.166, year: 2007

  10. 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.

  11. Validity of the t-plot method to assess microporosity in hierarchical micro/mesoporous materials.

    Science.gov (United States)

    Galarneau, Anne; Villemot, François; Rodriguez, Jeremy; Fajula, François; Coasne, Benoit

    2014-11-11

    The t-plot method is a well-known technique which allows determining the micro- and/or mesoporous volumes and the specific surface area of a sample by comparison with a reference adsorption isotherm of a nonporous material having the same surface chemistry. In this paper, the validity of the t-plot method is discussed in the case of hierarchical porous materials exhibiting both micro- and mesoporosities. Different hierarchical zeolites with MCM-41 type ordered mesoporosity are prepared using pseudomorphic transformation. For comparison, we also consider simple mechanical mixtures of microporous and mesoporous materials. We first show an intrinsic failure of the t-plot method; this method does not describe the fact that, for a given surface chemistry and pressure, the thickness of the film adsorbed in micropores or small mesopores (plot method to estimate the micro- and mesoporous volumes of hierarchical samples is then discussed, and an abacus is given to correct the underestimated microporous volume by the t-plot method.

  12. Mesoporous silica wrapped with graphene oxide-conducting PANI nanowires as a novel hybrid electrode for supercapacitor

    Science.gov (United States)

    Javed, Mohsin; Abbas, Syed Mustansar; Siddiq, Mohammad; Han, Dongxue; Niu, Li

    2018-02-01

    A high charge-carrier transport is an important aim in the synthesis of nanostructures for an effective supercapacitor. This article describes a methodology to prepare mesoporous silica nanoparticles (MSNs) wrapped with graphene oxide (GO) together with conducting polyaniline (PANI) wires. The morphology and chemical structure of the prepared samples have been tested by transmission electron microscopy (TEM), high-resolution TEM (HRTEM), and X-ray diffraction (XRD), whereas the stability and electrostatic interaction of the structures have been verified by thermogravimetric analysis (TGA) and Fourier-transform infrared (FT-IR) spectroscopy, respectively. The supercapacitive behaviour of these nanocomposites has been analysed by cyclic voltammetry (CV), charge-discharge tests, and electrochemical impedance spectroscopy (EIS). Compared with pristine MSNs and PANI, the 20%-GO@MSNs/PANI nanocomposite had the highest specific capacitance, reaching 412 F g-1. The nanocomposite structure maximizes the synergy between mesoporous metal oxide, conducting PANI, and GO, yielding a significantly enhanced specific capacitance, rapid charge-discharge rates, and good cycling stability of the resulting device. The wrapping with GO prevents the structural breakdown and acts as a highly conductive pathway by bridging the individual particles, whereas the MSNs nanoparticles greatly enlarge the specific surface area to facilitate ion transport and charge transfer throughout the cycling performance of supercapacitor. The approach adopted in this article can be applied for preparing similar novel functional materials in future for electrochemical applications.

  13. Mesoporous Silica Supported Au Nanoparticles with Controlled Size as Efficient Heterogeneous Catalyst for Aerobic Oxidation of Alcohols

    Directory of Open Access Journals (Sweden)

    Xuefeng Chu

    2015-01-01

    Full Text Available A series of Au catalysts with different sizes were synthesized and employed on amine group functionalized ordered mesoporous silica solid supports as catalyst for the aerobic oxidation of various alcohols. The mesoporous silica of MCM-41 supported Au nanoparticles (Au-1 exhibited the smallest particle size at ~1.8 nm with superior catalytic activities owing to the confinement effect of the mesoporous channels. Au-1 catalyst is also very stable and reusable under aerobic condition. Therefore, this presented work would obviously provide us a platform for synthesizing more size-controlled metal catalysts to improve the catalytic performances.

  14. Active Iron Sites of Disordered Mesoporous Silica Catalyst FeKIL-2 in the Oxidation of Volatile Organic Compounds (VOC

    Directory of Open Access Journals (Sweden)

    Mojca Rangus

    2014-05-01

    Full Text Available Iron-functionalized disordered mesoporous silica (FeKIL-2 is a promising, environmentally friendly, cost-effective and highly efficient catalyst for the elimination of volatile organic compounds (VOCs from polluted air via catalytic oxidation. In this study, we investigated the type of catalytically active iron sites for different iron concentrations in FeKIL-2 catalysts using advanced characterization of the local environment of iron atoms by a combination of X-ray Absorption Spectroscopy Techniques (XANES, EXAFS and Atomic-Resolution Scanning Transmission Electron Microscopy (AR STEM. We found that the molar ratio Fe/Si ≤ 0.01 leads to the formation of stable, mostly isolated Fe3+ sites in the silica matrix, while higher iron content Fe/Si > 0.01 leads to the formation of oligonuclear iron clusters. STEM imaging and EELS techniques confirmed the existence of these clusters. Their size ranges from one to a few nanometers, and they are unevenly distributed throughout the material. The size of the clusters was also found to be similar, regardless of the nominal concentration of iron (Fe/Si = 0.02 and Fe/Si = 0.05. From the results obtained from sample characterization and model catalytic tests, we established that the enhanced activity of FeKIL-2 with the optimal Fe/Si = 0.01 ratio can be attributed to: (1 the optimal concentration of stable isolated Fe3+ in the silica support; and (2 accelerated diffusion of the reactants in disordered mesoporous silica (FeKIL-2 when compared to ordered mesoporous silica materials (FeSBA-15, FeMCM-41.

  15. Influence of metal loading on hydrocracking of rapeseed oil using bifunctional micro-/mesoporous composite materials

    Energy Technology Data Exchange (ETDEWEB)

    Gille, T.; Busse, O.; Reschetilowski, W. [Technische Univ. Dresden (Germany). Inst. of Industrial Chemistry

    2013-11-01

    Hydrocracking of rapeseed oil has been investigated in a fixed bed reactor under integral conditions. A synthesized micro-/mesoporous composite material Al-MCM-41/ZSM-5 modified by different metal loadings (NiMo, PtNiMo, Pt) was used as catalyst system. It could be demonstrated that the support material and their metal loading influence the product selectivity as well as the deactivation tendencies of the catalyst sample. (orig.)

  16. Nanocasting of Periodic Mesoporous Materials as an Effective Strategy to Prepare Mixed Phases of Titania

    Directory of Open Access Journals (Sweden)

    Luther Mahoney

    2015-12-01

    Full Text Available Mesoporous titanium dioxide materials were prepared using a nanocasting technique involving silica SBA-15 as the hard-template. At an optimal loading of titanium precursor, the hexagonal periodic array of pores in SBA-15 was retained. The phases of titanium dioxide could be easily varied by the number of impregnation cycles and the nature of titanium alkoxide employed. Low number of impregnation cycles produced mixed phases of anatase and TiO2(B. The mesoporous TiO2 materials were tested for solar hydrogen production, and the material consisting of 98% anatase and 2% TiO2(B exhibited the highest yield of hydrogen from the photocatalytic splitting of water. The periodicity of the pores was an important factor that influenced the photocatalytic activity. This study indicates that mixed phases of titania containing ordered array of pores can be prepared by using the nanocasting strategy.

  17. Mesoporous silica materials modified with alumina polycations as catalysts for the synthesis of dimethyl ether from methanol

    Energy Technology Data Exchange (ETDEWEB)

    Macina, Daniel; Piwowarska, Zofia; Tarach, Karolina; Góra-Marek, Kinga [Jagiellonian University, Faculty of Chemistry, Ingardena 3, 30-060 Kraków (Poland); Ryczkowski, Janusz [Maria Curie Skłodowska University, Faculty of Chemistry, Maria Curie-Skłodowska 2, 20-031 Lublin (Poland); Chmielarz, Lucjan, E-mail: chmielar@chemia.uj.edu.pl [Jagiellonian University, Faculty of Chemistry, Ingardena 3, 30-060 Kraków (Poland)

    2016-02-15

    Highlights: • Deposition of alumina ologoctaions on mesoporous silicas modified with surface −SO{sub 3}H groups. • Alumina aggregates generated acid properties in the silica supports. • Alumina modified SBA-15 and MCF were active and selective catalysts in DME synthesis. - Abstract: Mesoporous silica materials (SBA-15 and MCF) were used as catalytic supports for the deposition of aggregated alumina species using the method consisting of the following steps: (i) anchoring 3-(mercaptopropyl)trimethoxysilane (MPTMS) on the silica surface followed by (ii) oxidation of −SH to−SO{sub 3}H groups and then (iii) deposition of aluminum Keggin oligocations by ion-exchange method and (iv) calcination. The obtained samples were tested as catalysts for synthesis of dimethyl ether from methanol. The modified silicas were characterized with respect to the ordering of their porous structure (XRD), textural properties (BET), chemical composition (EDS, CHNS), structure ({sup 27}Al NMR, FTIR) and location of alumina species (EDX-TEM), surface acidity (NH{sub 3}-TPD, Py-FTIR) and thermal stability (TGA). The obtained materials were found to be active and selective catalysts for methanol dehydration to dimethyl ether (DME) in the MTD process (methanol-to-dimethyl ether).

  18. 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....

  19. Batch fabrication of mesoporous boron-doped nickel oxide nanoflowers for electrochemical capacitors

    International Nuclear Information System (INIS)

    Yang, Jing-He; Yu, Qingtao; Li, Yamin; Mao, Liqun; Ma, Ding

    2014-01-01

    Highlights: • A new facile liquid-phase method has been employed for synthesis boron-doped NiO nanoflowers. • The specific surface area of NiO is as high as 200 m 2 g −1 . • NiO nanoflowers exhibit a high specific capacitance of ∼1309 F g −1 at a charge and discharge current density of 3 A g −1 . • NiO nanoflowers have excellent cycling ability and even after 2500 cycles there is no significant reduction in specific capacitance. - Abstract: Boron-doped nickel oxide (B-NiO) nanoflowers are prepared by simple thermal decomposition of nickel hydroxide. B-NiO is porous sphere with a diameter of about 400 nm. B-NiO nanoflowers are composed of approximately 30 nm nanoplates and the thickness of the nanosheets is approximately 3 nm. The specific surface area of the material is as high as 200 m 2 g −1 and the pore size distribution curves of B-NiO has three typical peaks in the range of mesoporous (5 nm, 13 nm and 18 nm). As an electrode for supercapacitors, the crystalline B-NiO nanoflowers have favorable characteristics, for instance, a specific capacitance of 1309 F g −1 at a current density of 3 A g −1 and no significant reduction in Coulombic efficiency after 2500 cycles at 37.5 A g −1 . This remarkable electrochemical performance will make B-NiO nanoflowers a promising electrode material for high performance supercapacitors

  20. 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.

  1. Micelle swelling agent derived cavities for increasing hydrophobic organic compound removal efficiency by mesoporous micelle@silica hybrid materials

    KAUST Repository

    Shi, Yifeng; Li, Bin; Wang, Peng; Dua, Rubal; Zhao, Dongyuan

    2012-01-01

    Mesoporous micelle@silica hybrid materials with 2D hexagonal mesostructures were synthesized as reusable sorbents for hydrophobic organic compounds (HOCs) removal by a facile one-step aqueous solution synthesis using 3-(trimethoxysily)propyl

  2. Synthesis and characterization of mesoporous Mn-MCM-41 materials

    International Nuclear Information System (INIS)

    Saladino, Maria Luisa; Kraleva, Elka; Todorova, Silvia; Spinella, Alberto; Nasillo, Giorgio; Caponetti, Eugenio

    2011-01-01

    Highlights: · Manganese MCM-41 as catalyst. · Influence of pH on the structure of MCM-41. · Influence of manganese on the structure and activity of Mn-MCM-41. - Abstract: MCM-41 has been synthesized at two different pH using cetyl-trimethylammonium bromide (CTAB) surfactant as template and adding the silica precursor to aqueous solutions containing CTAB. The obtained solids were calcined at 600 deg. C for 4 h. Mn-MCM-41 powders with different Mn/Si molar ratios were prepared using the incipient wetness method, followed by calcination at 550 deg. C for 5 h. At the end of the impregnation process the powders colour changed from white to brown whose intensity depends on manganese quantity. The materials characterization was performed by X-ray diffraction, N 2 adsorption, 29 Si Cross Polarization-Magic Angle Spinning NMR, and X-ray Photoelectron Spectroscopy. The effects of the manganese quantity and of the structural characteristic of the MCM-41 support were studied. The catalytic activity of the prepared systems was evaluated in a complete n-hexane oxidation.

  3. Catalytic removal of sulfur dioxide from dibenzothiophene sulfone over Mg-Al mixed oxides supported on mesoporous silica.

    Science.gov (United States)

    You, Nansuk; Kim, Min Ji; Jeong, Kwang-Eun; Jeong, Soon-Yong; Park, Young-Kwon; Jeon, Jong-Ki

    2010-05-01

    Dibenzothiophene sulfone (DBTS), one of the products of the oxidative desulfurization of heavy oil, can be removed through extraction as well as by an adsorption process. It is necessary to utilize DBTS in conjunction with catalytic cracking. An object of the present study is to provide an Mg-Al-mesoporous silica catalyst for the removal of sulfur dioxide from DBTS. The characteristics of the Mg-Al-mesoporous silica catalyst were investigated through N2 adsorption, XRD, ICP, and XRF. An Mg-Al-mesoporous silica catalyst formulated in a direct incorporation method showed higher catalytic performance compared to pure MgO during the catalytic removal of sulfur dioxide from DBTS. The higher dispersion of Mg as well as the large surface area of the Mg-Al-mesoporous silica catalyst strongly influenced the catalyst basicity in DBTS cracking.

  4. Controlled synthesis of the tricontinuous mesoporous material IBN-9 and its carbon and platinum derivatives

    KAUST Repository

    Zhao, Yunfeng

    2011-08-23

    Controlled synthesis of mesoporous materials with ultracomplicated pore configurations is of great importance for both fundamental research of nanostructures and the development of novel applications. IBN-9, which is the only tricontinuous mesoporous silica with three sets of interpenetrating three-dimensional channel systems, appears to be an excellent model mesophase for such study. The extensive study of synthesis space diagrams proves mesophase transition among the cylindrical MCM-41, tricontinuous IBN-9 and bicontinuous MCM-48, and also allows a more precise control of phase-pure synthesis. On the other hand, rational design of structure-directing agents offers a possibility to extend the synthesis conditions of IBN-9, as well as tailor its pore size. Moreover, an unprecedented helical structure consisting of twisted 3-fold interwoven mesoporous channels is reported here for the first time. The unique tricontinuous mesostructure of IBN-9 has been well-replicated by other functional materials (e.g., carbon and platinum) via a "hard- templating" synthesis route. The obtained carbon material possesses large surface area (∼1900 m2/g), high pore volume (1.56 cm 3/g), and remarkable gas adsorption capability at both cryogenic temperatures and room temperature. The platinum material has an ordered mesostructure composed of highly oriented nanocrystals. © 2011 American Chemical Society.

  5. Gelatin Template Synthesis of Aluminum Oxide and/or Silicon Oxide Containing Micro/Mesopores Using the Proteic Sol-Gel Method

    Directory of Open Access Journals (Sweden)

    Amanda Sayure Kasuya de Oliveira

    2017-01-01

    Full Text Available Aluminum oxide and/or silicon oxide-based supports were synthesized by proteic sol-gel method. The characterization was performed through the analysis of TG, XRD, FTIR, SEM, and N2 physisorption. The XRD diffractograms showed an amorphous material profile. TG results indicate the total liberation of the organic and inorganic material in the calcination temperature used, occurring in different mass loss range. This piece of information was reaffirmed by the FTIR spectra, which presented characteristic bands of gelatin structure before calcinations which disappear in the spectrum of the solid after calcinations, indicating the loss of organic matter from gelatin after heat treatment. The spectra exhibited M-O stretching vibration at low wavenumbers after calcinations related to metal oxides. The acquired images by SEM suggest the obtaining of a highly porous material with very different characteristics depending on the composition of the support. The N2 isotherms indicate the presence of a micro/mesoporous oxide with interesting textural properties, particularly for the supports containing aluminum and silicon oxide. The ethanol dehydration results showed greater selectivity to diethyl ether compared to ethylene. From the reaction data, the following order of acid strength was obtained: 2Si-Al > Si-2Al > Si-Al > Al, which is related to the Si-Al ratio.

  6. Cooperation of micro- and meso-porous carbon electrode materials in electric double-layer capacitors

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Cheng [State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, 5625 Renmin Street, Changchun 130022, Jilin Province (China); Graduate University of Chinese Academy of Sciences, Beijing 100039 (China); Qi, Li; Wang, Hongyu [State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, 5625 Renmin Street, Changchun 130022, Jilin Province (China); Yoshio, Masaki [Advanced Research Center, Saga University, 1341 Yoga-machi, Saga 840-0047 (Japan)

    2010-07-01

    The capacitive characteristics of micro- and meso-porous carbon materials have been compared in cyclic voltammetric studies and galvanostatic charge-discharge tests. Meso-porous carbon can keep certain high capacitance values at high scan rates, whereas micro-porous carbon possesses very high capacitance values at low scan rates but fades quickly as the scan rate rises up. For better performance of electric double-layer capacitors (EDLCs), the cooperative application of both kinds of carbon materials has been proposed in the following two ways: mixing both kinds of carbons in the same electrode or using the asymmetric configuration of carbon electrodes in the same EDLC. The cooperative effect on the electrochemical performance has also been addressed. (author)

  7. Synthesis of mesoporous aluminophosphate and silicoaluminophosphate in the presence of nonionic poly(ethylene oxide) surfactant

    International Nuclear Information System (INIS)

    Zhao, G.L.; Zhang, X.J.; Chen, T.H.; Yuan, Z.Y.

    2006-01-01

    Thermally stable mesoporous aluminophosphate and silicoaluminophosphate materials have been synthesized by using nonionic PEO-surfactant C 16 H 33 (PEO) 10 OH as a structure-directing agent. The synthesized aluminophosphate and silicoaluminophosphate possess disordered wormhole-like mesostructures with pore sizes of 3.8 and 5 nm, respectively. BET surface areas of 376-412 m 2 /g are obtained. Both four- and six-coordinate Al and tetrahedrally coordinated P were observed. It is believed that these materials may find potential applications in the fields of catalysis and material sciences

  8. Hydrocracking of ethyl laurate on bifunctional micro-/mesoporous composite materials

    Energy Technology Data Exchange (ETDEWEB)

    Adam, M.; Busse, O.; Reschetilowski, W. [Technische Univ. Dresden (Germany). Inst. for Industrial Chemistry

    2011-07-01

    Hydrocracking of ethyl laurate (dodecanoic acid ethyl ester) as a representative model compound of vegetable oil has been investigated in a fixed bed reactor under integral conditions. A synthesized micro-/mesoporous composite support material Al-MCM-41/ZSM-5 modified by different metal loadings (NiMo, NiW, PtNiW) was used as catalyst system. It could be demonstrated that the metal loading and reducibility influence product selectivity as well as deactivation behavior of catalyst samples. (orig.)

  9. Mesoporous Silica-Supported Metal Oxide-Promoted Rh Nanocatalyst for Selective Production of Ethanol from Syngas

    Energy Technology Data Exchange (ETDEWEB)

    Kraus, George

    2010-09-30

    The objective is to develop a process that will convert synthesis gas from coal into ethanol and then transform the ethanol into hydrogen. Principal investigators from Iowa State University include Dr. George Kraus, Dr. Victor Lin, Marek Pruski, and Dr. Robert Brown. Task 1 involves catalyst development and catalyst scale up. Mesoporous manganese silicate mixed oxide materials will be synthesized, characterized and evaluated. The first-and secondgeneration catalysts have been prepared and scaled up for use in Task 2. The construction of a high-pressure reactor system for producing synthetic liquid fuel from simulated synthesis gas stream has been completed as the first step in Task 2. Using the first- and second generation catalysts, the reactor has demonstrated the production of synthetic liquid fuel from a simulated synthesis gas stream.

  10. Removal of Congo Red by magnetic mesoporous titanium dioxide-graphene oxide core-shell microspheres for water purification.

    Science.gov (United States)

    Li, Leilei; Li, Xiangjun; Duan, Huimin; Wang, Xiaojiao; Luo, Chuannan

    2014-06-14

    Magnetic mesoporous titanium dioxide-graphene oxide (Fe3O4@mTiO2@GO) with a large surface area and a good magnetic responsiveness was synthesized by immobilizing a mesoporous titanium dioxide (mTiO2) shell on the surface of magnetic Fe3O4 nanoparticles prior to binding with graphene oxide (GO). It showed a tunable pore structure and surface properties, and was mechanically strong. The characteristic results of a Fourier transform infrared spectrometer (FTIR), a scanning electron microscope (SEM), a vibrating sample magnetometer (VSM) and X-ray diffraction (XRD) indicated that Fe3O4@mTiO2@GO has been prepared. Fe3O4@mTiO2@GO was used as an adsorbent for the removal of Congo Red (CR) from simulated wastewater with a fast solid-liquid separation in the presence of an external magnetic field. Batch adsorption experiments were performed to evaluate the adsorption conditions and reusability. The results showed that the maximum adsorption capacity was 89.95 mg g(-1), which is much higher than the previously reported values of other absorbent materials. Moreover, the Fe3O4@mTiO2@GO could be repeatedly used via simple treatment without any obvious structure and performance degradation. The adsorption kinetic data were best described by a pseudo-second-order model and the equilibrium adsorptions were well-described by the Freundlich isotherm model. The Fe3O4@mTiO2@GO may be suitable materials for use in CR pollution cleanup if synthesized on a large scale and at a low price in the near future.

  11. Mesoporous Niobium Oxide Spheres as an Effective Catalyst for the Transamidation of Primary Amides with Amines

    KAUST Repository

    Ghosh, Subhash Chandra; Li, Cheng Chao; Zeng, Hua Chun; Ngiam, Joyce S Y; Seayad, Abdul M.; Chen, Anqi

    2014-01-01

    Mesoporous niobium oxide spheres (MNOS), conveniently prepared by a novel antisolvent precipitation approach, have been shown to be an effective catalyst for the transamidation of primary amides with amines. This novel transamidation can be efficiently carried out under solvent-free conditions and is applicable to a wide range of primary amides and amines to provide N-alkyl amides in good to excellent yields. The catalyst is highly stable and reusable. The application of this transamidation reaction has been demonstrated in the synthesis of antidepressant drug moclobemide and other druglike compounds. © 2014 Wiley-VCH Verlag GmbH&Co. KGaA, Weinheim.

  12. Mesoporous Niobium Oxide Spheres as an Effective Catalyst for the Transamidation of Primary Amides with Amines

    KAUST Repository

    Ghosh, Subhash Chandra

    2014-02-06

    Mesoporous niobium oxide spheres (MNOS), conveniently prepared by a novel antisolvent precipitation approach, have been shown to be an effective catalyst for the transamidation of primary amides with amines. This novel transamidation can be efficiently carried out under solvent-free conditions and is applicable to a wide range of primary amides and amines to provide N-alkyl amides in good to excellent yields. The catalyst is highly stable and reusable. The application of this transamidation reaction has been demonstrated in the synthesis of antidepressant drug moclobemide and other druglike compounds. © 2014 Wiley-VCH Verlag GmbH&Co. KGaA, Weinheim.

  13. Steam-assisted crystallization of TPA+-exchanged MCM-41 type mesoporous materials with thick pore walls

    International Nuclear Information System (INIS)

    Chen, Hong Li; Zhang, Kun; Wang, Yi Meng

    2012-01-01

    Highlights: ► Mesoporous Ti-containing silica with thicker pore walls was synthesized. ► Ion-exchange and steam-assisted crystallization led to MCM-41/MFI composite. ► The introduction of Ti inhibited the formation of separated MFI particles. ► Lower temperature favored retaining mesoporous characteristics and morphology. -- Abstract: Hierarchical MCM-41/MFI composites were synthesized through ion-exchange of as-made MCM-41 type mesoporous materials with tetrapropylammonium bromide and subsequent steam-assisted recrystallization. The obtained samples were characterized by powder X-ray diffraction (XRD), UV–vis diffuse reflectance spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetric analysis, FT-IR, 1 H– 13 C CP/MAS and nitrogen adsorption–desorption. The XRD patterns show that the MCM-41/MFI composite possesses both ordered MCM-41 phase and zeolite MFI phase. SEM and TEM images indicate that the recrystallized materials retained the mesoporous characteristics and the morphology of as-made mesoporous materials without the formation of bulky zeolite, quite different from the mechanical mixture of MCM-41 and MFI structured zeolite. Among others, lower recrystallization temperature and the introduction of the titanium to the parent materials are beneficial to preserve the mesoporous structure during the recrystallization process.

  14. Selective Preparation of Furfural from Xylose over Sulfonic Acid Functionalized Mesoporous Sba-15 Materials

    Directory of Open Access Journals (Sweden)

    Panpan Li

    2011-04-01

    Full Text Available Sulfonic acid functionalized mesoporous SBA-15 materials were prepared using the co-condensation and grafting methods, respectively, and their catalytic performance in the dehydration of xylose to furfural was examined. SBA-15-SO3H(C prepared by the co-condensation method showed 92–95% xylose conversion and 74% furfural selectivity, and 68–70% furfural yield under the given reaction conditions. The deactivation and regeneration of the SBA-15-SO3H(C catalyst for the dehydration of xylose was also investigated. The results indicate that the used and regeneration catalysts retained the SBA-15 mesoporous structure, and the S content of SBA-15-SO3H(C almost did not change. The deactivation of the catalysts is proposed to be associated with the accumulation of byproducts, which is caused by the loss reaction of furfural. After regeneration by H2O2, the catalytic activity of the catalyst almost recovered.

  15. Hydrodeoxygenation of Pyrolysis Bio-Oil Over Ni Impregnated Mesoporous Materials.

    Science.gov (United States)

    Lee, In-Gu; Lee, Heejin; Kang, Bo Sung; Kim, Young-Min; Kim, Sang Chai; Jung, Sang-Chul; Ko, Chang Hyun; Park, Young-Kwon

    2018-02-01

    The catalytic hydrodeoxygenation (HDO) of bio-oil over Ni-supported mesoporous materials was performed using a high pressure autoclave reactor. The actual pyrolysis oil of cork oak wood was used as a sample, and Ni/Al-SBA-15 and Ni/Al-MSU-F were used as catalysts. In addition, supercritical ethanol was added as solvent. Both Ni-supported mesoporous catalysts showed efficient HDO reaction ability. A higher heating value and pH of bio-oil were achieved by the HDO reaction over both catalysts and upgraded bio-oil had a lower viscosity. Compared to Ni/Al-MSU-F, Ni/Al- SBA-15 produced more upgraded bio-oil with a lower oxygen content and higher heating value via a catalytic HDO process.

  16. Hierarchically mesoporous silica materials prepared from the uniaxially stretched polypropylene membrane and surfactant templates

    International Nuclear Information System (INIS)

    Wang Xiaocong; Ma Jin; Liu Jin; Zhou Chen; Zhao, Yan; Yi Shouzhi; Yang Zhenzhong

    2006-01-01

    Hierarchically mesoporous silica materials with a bimodal distribution were template-prepared from uniaxially stretched polypropylene membrane in the presence of a surfactant via a sol-gel process. Their regularity and morphologies were characterized by transmission electron microscopy (TEM), x-ray diffraction and Brunauer-Emmett-Teller (BET) surface area analysis. The larger channel pores formed by removing the microfibrils of uniaxially stretched polypropylene membrane have a broad pore size distribution, and their size is around 13 nm. In contrast, the smaller mesopores formed by surfactant templates have a narrow distribution; their size is about 3.9 nm. The size of the smaller pores could be tuned from 2 to 6 nm by selecting different surfactants and by changing the concentration of reactants

  17. Optical oxygen sensing materials based on a novel dirhenium(I) complex assembled in mesoporous silica

    International Nuclear Information System (INIS)

    Liu Yanhong; Li Bin; Cong Yan; Zhang Liming; Fan Di; Shi Linfang

    2011-01-01

    A new dirhenium(I) complex fac-[{Re(CO) 3 (4,7-dinonadecyl-1,10-phenanthro -line)} 2 (4,4'-bipyridyl)] (trifluoromethanesulfonate) 2 (denoted as D-Re(I) ) is assembled in MCM-41 and SBA-15 type mesoporous silica support. The emission peaks of D-Re(I) in D-Re(I)/MCM-41 and D-Re(I)/SBA-15 are observed at 522 and 517 nm, respectively. Their long excited lifetimes, which are of the order of microseconds, indicate the presence of phosphorescence emission arising from the metal to ligand charge-transfer (MLCT) transition. The luminescence intensities of D-Re(I)/MCM-41 and D-Re(I)/SBA-15 decrease remarkably with increase in the oxygen concentration, meaning that they can be used as optical oxygen sensing materials based on luminescence quenching. The ratios I 0 /I 100 of D-Re(I)/MCM-41 and D-Re(I)/SBA-15 are estimated to be 5.6 and 20.1, respectively. The obtained Stern-Volmer oxygen quenching plots of the mesoporous sensing materials could be fitted well to the two-site Demas model and Lehrer model. - Research highlights: → Dirhenium(I) complex assembled in mesoporous molecular sieves for oxygen sensor design. → Large α-diimine ligand L used to improve oxygen sensing properties. → High sensitivity (I 0 /I 100 ) up to 20.1.

  18. Hydrogen incorporation by plasma treatment gives mesoporous black TiO 2 thin films with visible photoelectrochemical water oxidation activity

    Energy Technology Data Exchange (ETDEWEB)

    Islam, Syed Z.; Reed, Allen; Nagpure, Suraj; Wanninayake, Namal; Browning, James F.; Strzalka, Joseph; Kim, Doo Young; Rankin, Stephen E.

    2018-05-01

    In this work, we use neutron reflectometry (NR) to investigate the roles of hydrogen in plasma treated hydrogen doped mesoporous black titania thin films in their visible light absorption and enhanced photoactivity for water oxidation. The cubic ordered mesoporous TiO2 thin films are prepared by a surfactant-templated sol-gel method and are treated with hydrogen plasma, an approach hypothesized to capitalize on the high degree of disorder in the material and the high energy of the plasma species to achieve efficient hydrogen doping. UV-vis absorbance spectra indicate that H2 plasma treatment makes TiO2 films black, with broad-spectrum enhancement of visible light absorption, and XPS analysis shows peak for Ti3+ state in treated films. The presence of hydrogen in black mesoporous titania (H-TiO2) films is confirmed by the scattering length density (SLD) profiles obtained from neutron reflectometry measurements. The H-TiO2 shows ca. 28 times and 8 times higher photocurrent for photoelectrochemical water oxidation compared to undoped TiO2 films under UV (365 nm) and blue (455 nm) LED irradiation, respectively. These findings provide the first direct evidence that the dramatic change in visible light absorbance of H-treated black TiO2 is accompanied by significant hydrogen uptake and not just Ti3+ generation or surface disordering.

  19. 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.

  20. Easy and General Synthesis of Large-Sized Mesoporous Rare-Earth Oxide Thin Films by 'Micelle Assembly'.

    Science.gov (United States)

    Li, Yunqi; Bastakoti, Bishnu Prasad; Imura, Masataka; Dai, Pengcheng; Yamauchi, Yusuke

    2015-12-01

    Large-sized (ca. 40 nm) mesoporous Er2O3 thin films are synthesized by using a triblock copolymer poly(styrene-b-2-vinyl pyridine-b-ethylene oxide) (PS-b-P2VP-b-PEO) as a pore directing agent. Each block makes different contributions and the molar ratio of PVP/Er(3+) is crucial to guide the resultant mesoporous structure. An easy and general method is proposed and used to prepare a series of mesoporous rare-earth oxide (Sm2O3, Dy2O3, Tb2O3, Ho2O3, Yb2O3, and Lu2O3) thin films with potential uses in electronics and optical devices. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. 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.

  2. Controllable synthesis of mesoporous multi-shelled ZnO microspheres as efficient photocatalysts for NO oxidation

    Science.gov (United States)

    Chen, Xiaolang; Zhang, Huiqiang; Zhang, Dieqing; Miao, Yingchun; Li, Guisheng

    2018-03-01

    The successful application of hierarchically porous structure in environmental treatment has provided new insights for solving environmental problems. Hierarchically structured semiconductor materials were considered as promising photocatalysts for NO oxidation in gas phase. Multi-shelled ZnO microspheres (MMSZ) were controllably shaped with hierarchically porous structures via a facile hydrothermal route using amino acid (N-Acetyl-D-Proline) as template and post-calcination treatment. Symmetric Ostwald ripening was used to explain the morphological evolution of hierarchical nanostructure. MMSZ was proved highly efficient for oxidizing NO (400 ppb) in gas phase under UV light irradiation with a much higher photocatalytic removal rate (77.3%) than that of the as-obtained ZnO crystals with other hierachically porous structures, owing to its higher photocurrent intensity. Such greatly enhanced photocatalytic activity can be assigned to the enhanced crystallinity of ZnO, mesopores and unique multi-shelled structure. Enhanced crystallinity promotes photogenerated charges under light irradiation. Mesoporous porosity can ensure enough light scattering between the shells. Multi-shelled structure endows ZnO with higher specific surface area and high frequency of multiple light reflection, resulting in more exposed active sites, higher light utilization efficiency, and fast separation efficiency of photogenerated charge carriers. The experimental results demonstrated that the photogenerated holes (h+) are the main active species. Hierarchically structured ZnO is not only contributed to directly use solar energy to solving various problems caused by atmospheric pollution, but also has potential applications in energy converse and storage including solar cells, lithium batteries, water-splitting, etc.

  3. Enantioselectively controlled release of chiral drug (metoprolol) using chiral mesoporous silica materials

    International Nuclear Information System (INIS)

    Guo Zhen; Liu Xianbin; Ng, Siu-Choon; Chen Yuan; Yang Yanhui; Du Yu

    2010-01-01

    Chiral porous materials have attracted burgeoning attention on account of their potential applications in many areas, such as enantioseparation, chiral catalysis, chemical sensors and drug delivery. In this report, chiral mesoporous silica (CMS) materials with various pore sizes and structures were prepared using conventional achiral templates (other than chiral surfactant) and a chiral cobalt complex as co-template. The synthesized CMS materials were characterized by x-ray diffraction, nitrogen physisorption, scanning electron microscope and transmission electron microscope. These CMS materials, as carriers, were demonstrated to be able to control the enantioselective release of a representative chiral drug (metoprolol). The release kinetics, as modeled by the power law equation, suggested that the release profiles of metoprolol were remarkably dependent on the pore diameter and pore structure of CMS materials. More importantly, R- and S-enantiomers of metoprolol exhibited different release kinetics on CMS compared to the corresponding achiral mesoporous silica (ACMS), attributable to the existence of local chirality on the pore wall surface of CMS materials. The chirality of CMS materials on a molecular level was further substantiated by vibrational circular dichroism measurements.

  4. Enantioselectively controlled release of chiral drug (metoprolol) using chiral mesoporous silica materials

    Energy Technology Data Exchange (ETDEWEB)

    Guo Zhen; Liu Xianbin; Ng, Siu-Choon; Chen Yuan; Yang Yanhui [School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore 637459 (Singapore); Du Yu, E-mail: du_yu@jlu.edu.cn, E-mail: yhyang@ntu.edu.sg [College of Electronic Science and Engineering, Jilin University, Changchun 130012 (China)

    2010-04-23

    Chiral porous materials have attracted burgeoning attention on account of their potential applications in many areas, such as enantioseparation, chiral catalysis, chemical sensors and drug delivery. In this report, chiral mesoporous silica (CMS) materials with various pore sizes and structures were prepared using conventional achiral templates (other than chiral surfactant) and a chiral cobalt complex as co-template. The synthesized CMS materials were characterized by x-ray diffraction, nitrogen physisorption, scanning electron microscope and transmission electron microscope. These CMS materials, as carriers, were demonstrated to be able to control the enantioselective release of a representative chiral drug (metoprolol). The release kinetics, as modeled by the power law equation, suggested that the release profiles of metoprolol were remarkably dependent on the pore diameter and pore structure of CMS materials. More importantly, R- and S-enantiomers of metoprolol exhibited different release kinetics on CMS compared to the corresponding achiral mesoporous silica (ACMS), attributable to the existence of local chirality on the pore wall surface of CMS materials. The chirality of CMS materials on a molecular level was further substantiated by vibrational circular dichroism measurements.

  5. Synthesis and Charaterization of Magensium Oxide Mesoporous Microstructures Using Pluronic F127

    Directory of Open Access Journals (Sweden)

    A. Tadjarodi

    2012-09-01

    Full Text Available Mesoporous  MgO  microstructures  were  synthesized  using magnesium  acetate  tetrahydrate,  ammonium  oxalate  monohydrate and  Pluronic  F127  via  heating  at  40  °C  for  24  h  and  subsequent calcination. The mesoporous structure of magnesium oxide with the specific  surface  area  of  47m2 /g,  pore  volume  0.30  cm3 /g  and  the average pore size 24 nm is produced. According to XRD studies, the diffraction peaks of  the product pattern can be  indexed  to  the cubic structure magnesium oxide with  the  lattice parameter of a = 4.22 Å and  showing  no  impurities.  The  product  was  characterized  by Fourier  transform  infrared  spectroscopy,  X-ray  powder  diffraction analysis,  N2  adsorption-desorption  and  Scanning  electron microscopy.

  6. Synthesis of mesoporous cerium-zirconium mixed oxides by hydrothermal templating method

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Mesoporous cerium-zirconium mixed oxides were prepared by hydrothermal method using cetyl trimethyl ammonium bromide (CTAB) as template.The effects of amount of template,pH value of solution and hydrothermal temperature on mesostructure of samples were systematically investigated.The final products were characterized by XRD,TEM,FT-IR,and BET.The results indicate that all the cerium-zirconium mixed oxides present a meso-structure.At molar ratio of n(CTAB)/n((Ce)+(Zr))=0.15,pH value of 9,and hydrothermal temperature of 120 ℃,the samples obtained possess a specific surface area of 207.9 m2/g with pore diameter of 3.70 nm and pore volume of 0.19 cm3/g.

  7. 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.

  8. Micelle swelling agent derived cavities for increasing hydrophobic organic compound removal efficiency by mesoporous micelle@silica hybrid materials

    KAUST Repository

    Shi, Yifeng

    2012-06-01

    Mesoporous micelle@silica hybrid materials with 2D hexagonal mesostructures were synthesized as reusable sorbents for hydrophobic organic compounds (HOCs) removal by a facile one-step aqueous solution synthesis using 3-(trimethoxysily)propyl-octadecyldimethyl-ammonium chloride (TPODAC) as a structure directing agent. The mesopores were generated by adding micelle swelling agent, 1,3,5-trimethyl benzene, during the synthesis and removing it afterward, which was demonstrated to greatly increase the HOC removal efficiency. In this material, TPODAC surfactant is directly anchored on the pore surface of mesoporous silica via SiOSi covalent bond after the synthesis due to its reactive Si(OCH 3) 3 head group, and thus makes the synthesized materials can be easily regenerated for reuse. The obtained materials show great potential in water treatment as pollutants sorbents. © 2011 Elsevier Inc. All rights reserved.

  9. 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.

  10. Effect of Mesoporous Chitosan Action and Coordination on the Catalytic Activity of Mesoporous Chitosan-Grafted Cobalt Tetrakis(p-SulfophenylPorphyrin for Ethylbenzene Oxidation

    Directory of Open Access Journals (Sweden)

    Guan Huang

    2018-05-01

    Full Text Available To simulate the active site cavity structure function and axial coordination of cytochrome P-450 enzymes, mesoporous chitosan(mesp-CTS was used as a scaffold for a meso-sized cavity to immobilize cobalt tetrakis(p-sulphophenylporphyrin chloride(Co TPPS. Immobilization was achieved via an acid–base reaction and axial coordination of the H2N-C group to the Co ion in Co TPPS, thus forming the biomimetic catalyst Co TPPS/mesp-CTS. Several approaches, including scanning electron microscopy (SEM, the Brunauer–Emmett–Teller (BETtechnique, Fourier transform infrared (FT-IR spectroscopy, ultraviolet-visible (UV-vis spectroscopy, thermogravimetric and differential scanning calorimetry (TG-DSC, and X-ray photoelectron spectroscopy (XPS, were used to characterize the grafted catalyst. The catalytic performance of Co TPPS/mesp-CTS in ethylbenzene oxidation without any solvents and additives was investigated. The results showed that only 0.96 × 10 mol of Co TPPS grafted onto mesp-CTS could be recycled three times for 200 mL of ethylbenzene oxidation, with an average yield of 44.6% and selectivity of 68.8%. The highly efficient catalysis can be attributed to promotion by mesp-CTS, including the effect of the mesoporous structure and the axial coordination to the Co ion in Co TPPS. This biomimetic methodology provides a method for clean production of acetophenone via ethylbenzene oxidation.

  11. 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.

  12. Mesoporous PtSnO2/C Catalyst with Enhanced Catalytic Activity for Ethanol Electro-oxidation

    Directory of Open Access Journals (Sweden)

    Siyu Chen

    2018-01-01

    Full Text Available In this paper, we report the synthesis, characterization, and electrochemical evaluation of a mesoporous PtSnO2/C catalyst, called PtSnO2(M/C, with a nominal Pt : Sn ratio of 3 : 1. Brunauer–Emmett–Teller and transmission electron microscopy characterizations showed the obvious mesoporous structure of SnO2 in PtSnO2(M/C catalyst. X-ray photoelectron spectroscopy analysis exhibited the interaction between Pt and mesoporous SnO2. Compared with Pt/C and commercial PtSnO2/C catalysts, PtSnO2(M/C catalyst has a lower active site, but higher catalytic activity for ethanol electro-oxidation reaction (EOR. The enhanced activity could be attributed to Pt nanoparticles deposited on mesoporous SnO2 that could decrease the amount of poisonous intermediates produced during EOR by the interaction between Pt and mesoporous SnO2.

  13. Oxidation of refractory sulfur compounds over Ti-containing mesoporous molecular sieves prepared by using a fluorosilicon compound.

    Science.gov (United States)

    Jeong, Kwang-Eun; Cho, Chin-Soo; Chae, Ho-Jeong; Kim, Chul-Ung; Jeong, Soon-Yong

    2010-05-01

    Titanium containing mesoporous molecular sieve (Ti-MMS) catalysts were studied for the oxidative desulfurization of refractory sulfur compounds. Ti-MMS catalysts were synthesized from fluorosilicon compounds and Ti with the hydrolysis reaction of H2SiF6 in an ammonia-surfactant mixed solution. The solid products were characterized by XRD, XRF, nitrogen adsorption, and diffuse reflectance UV-vis spectroscopy. Effects of Ti loading and oxidant/sulfur mole ratio, and sulfur species on ODS activity were investigated.

  14. Nickel cobalt oxide nanowire-reduced graphite oxide composite material and its application for high performance supercapacitor electrode material.

    Science.gov (United States)

    Wang, Xu; Yan, Chaoyi; Sumboja, Afriyanti; Lee, Pooi See

    2014-09-01

    In this paper, we report a facile synthesis method of mesoporous nickel cobalt oxide (NiCo2O4) nanowire-reduced graphite oxide (rGO) composite material by urea induced hydrolysis reaction, followed by sintering at 300 degrees C. P123 was used to stabilize the GO during synthesis, which resulted in a uniform coating of NiCo2O4 nanowire on rGO sheet. The growth mechanism of the composite material is discussed in detail. The NiCo2O4-rGO composite material showed an outstanding electrochemical performance of 873 F g(-1) at 0.5 A g(-1) and 512 F g(-1) at 40 A g(-1). This method provides a promising approach towards low cost and large scale production of supercapacitor electrode material.

  15. Coordination and Oxidation States of Iron Incorporated in Mesoporous MCM41

    International Nuclear Information System (INIS)

    Lazar, K.; Pal-Borbely, G.; Szegedi, A.; Beyer, H. K.

    2002-01-01

    Mesoporous Fe-MCM41 samples (Si/Fe=25) were synthesized and characterized under evacuation and reducing/oxidizing treatments by in situ FTIR and Moessbauer spectroscopies. Both Fe(II) and Fe(III) located in low coordination states in top layers of pore walls exhibit Lewis acidity and may participate in Fe(III) ↔ Fe(II) processes at low temperatures (570 K). Furthermore, Fe(III) ↔ Fe(II) cycles can be achieved and repeated with participation of the full amount of iron at higher temperatures (670 K). The accompanying formation of oxygen vacancies and restoration of the structure in the reverse process does not result in extended damages; the MCM41 structure retains its stability under the conditions applied.

  16. Heterogeneous oxidative desulfurization of diesel fuel catalyzed by mesoporous polyoxometallate-based polymeric hybrid.

    Science.gov (United States)

    Yang, Huawei; Jiang, Bin; Sun, Yongli; Zhang, Luhong; Huang, Zhaohe; Sun, Zhaoning; Yang, Na

    2017-07-05

    In this work, the simple preparation of novel polymer supported polyoxometallates (POMs) catalysts has been reported. Soluble task-specific cross-linked poly (ionic liquid) (PIL) was prepared with N,​N-​dimethyl-​dodecyl-​(4-​vinylbenzyl) ammonium chloride and divinylbenzene as co-monomers. The as-prepared cationic PILs were assembled with different commercial POMs to form the interlinked mesoporous catalysts, and the formation mechanism was provided. The catalytic oxidation activities of the catalysts were closely related to the formation pathway of their corresponding peroxide active species. The catalyst with H 2 W 12 O 42 10- as counterion, which exhibited the best activity in the oxidation of benzothiophene (BT) and dibenzothiophene (DBT) to sulfones in model oil with hydrogen peroxide (H 2 O 2 , 30wt%) as oxidant, was characterized by different techniques and systematically studied for its sulfur removal performance. As for the oxidative desulfurization of a real diesel, it was observed that almost all of the original sulfur compounds could be completely converted, and the catalyst could be reused for at least eight cycles without noticeable changes in both catalytic activity and chemical structure. In the end, a catalytic mechanism was put forward with the assistant of Raman analysis. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. 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.

  18. Investigating the Effects of Loading Factors on the In Vitro Pharmaceutical Performance of Mesoporous Materials as Drug Carriers for Ibuprofen

    Directory of Open Access Journals (Sweden)

    Junmin Lai

    2017-02-01

    Full Text Available The aim of the study was to investigate the effects of the loading factors, i.e., the initial drug loading concentration and the ratio of the drug to carriers, on the in vitro pharmaceutical performance of drug-loaded mesoporous systems. Ibuprofen (IBU was used as a model drug, and two non-ordered mesoporous materials of commercial silica Syloid® 244FP (S244FP and Neusilin® US2 (NS2 were selected in the study. The IBU-loaded mesoporous samples were prepared by a solvent immersion method with a rotary evaporation drying technique and characterized by polarized light microscopy (PLM, Fourier transform infrared (FTIR spectroscopy, X-ray powder diffraction (XRPD and differential scanning calorimetry (DSC. Dissolution experiments were performed in simulated gastric media at 37 °C under non-sink conditions. The concentration of IBU in solution was determined by HPLC. The study showed that the dissolution rate of IBU can be improved significantly using the mesoporous S224FP carriers due to the conversion of crystalline IBU into the amorphous form. Both of the loading factors affected the IBU dissolution kinetics. Due to the molecular interaction between the IBU and NS2 carriers, the loading factors had little effects on the drug release kinetics with incomplete drug desorption recovery and insignificant dissolution enhancement. Care and extensive evaluation must therefore be taken when mesoporous materials are chosen as carrier delivery systems.

  19. 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.

  20. The micro and meso-porous materials. Characterization; Les materiaux micro et mesoporeux. Caracterisation

    Energy Technology Data Exchange (ETDEWEB)

    Thibault-Starzyk, F.

    2004-10-01

    The micro and meso-porous materials, called zeolites, are very important in the modern chemical industry and in petrochemistry. This book deals in particular with the study and the characterization of zeolites. Its aim is to give to generalist chemists the tools for approaching experimentally these particular materials. The main methods of study and characterization are gathered in eight chapters, and the authors stress on the specificities due to the porous system: -structural analysis by the diffraction methods; -infrared spectroscopy; -NMR; -micro-calorimetry; -adsorption thermodynamics; -methods using the programed temperature; -modeling; -reactivity: kinetics and chemical engineering. This book appeals to students, engineers or searchers, without previous knowledge on these materials, but having a bachelor's degree or a master degree in general chemistry. (O.M.)

  1. Synthesis of cobalt-containing mesoporous catalysts using the ultrasonic-assisted “pH-adjusting” method: Importance of cobalt species in styrene oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Li, Baitao, E-mail: btli@scut.edu.cn; Zhu, Yanrun; Jin, Xiaojing

    2015-01-15

    Cobalt-containing SBA-15 and MCM-41 (Co-SBA-15 and Co-MCM-41) mesoporous catalysts were prepared via ultrasonic-assisted “pH-adjusting” technique in this study. Their physiochemical structures were comprehensively characterized and correlated with catalytic activity in oxidation of styrene. The nature of cobalt species depended on the type of mesoporous silica as well as pH values. The different catalytic performance between Co-SBA-15 and Co-MCM-41 catalysts originated from cobalt species. Cobalt species were homogenously incorporated into the siliceous framework of Co-SBA-15 in single-site Co(II) state, while Co{sub 3}O{sub 4} particles were loaded on Co-MCM-41 catalysts. The styrene oxidation tests showed that the single-site Co(II) state was more beneficial to the catalytic oxidation of styrene. The higher styrene conversion and benzaldehyde selectivity over Co-SBA-15 catalysts were mainly attributed to single-site Co(II) state incorporated into the framework of SBA-15. The highest conversion of styrene (34.7%) with benzaldehyde selectivity of 88.2% was obtained over Co-SBA-15 catalyst prepared at pH of 7.5, at the mole ratio of 1:1 (styrene to H{sub 2}O{sub 2}) at 70 °C. - Graphical abstract: Cobalt-containing mesoporous silica catalysts were developed via ultrasonic-assisted “pH-adjusting” technique. Compared with Co{sub 3}O{sub 4} in Co-MCM-41, the single-site Co(II) state in Co-SBA-15 was more efficient for the styrene oxidation. - Highlights: • Fast and cost-effective ultrasonic technique for preparing mesoporous materials. • Incorporation of Co via ultrasonic irradiation and “pH-adjusting”. • Physicochemical comparison between Co-SBA-15 and Co-MCM-41. • Correlation of styrene oxidation activity and catalyst structural property.

  2. 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.

  3. Synthesis of mesoporous TS-1 using a hybrid SiO{sub 2}–TiO{sub 2} xerogel for catalytic oxidative desulfurization

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Seung-Tae [Department of Chemical Engineering, Inha University, Incheon 402-751 (Korea, Republic of); Jeong, Kwang-Eun; Jeong, Soon-Yong [Research Center for Green Catalysis, Division of Green Chemistry and Engineering Research, Korea Research Institute of Chemical Technology, P.O. Box 107, 141 Gajeong-ro, Yuseong, Daejeon 305-600 (Korea, Republic of); Ahn, Wha-Seung, E-mail: whasahn@inha.ac.kr [Department of Chemical Engineering, Inha University, Incheon 402-751 (Korea, Republic of)

    2012-12-15

    Graphical abstract: Display Omitted Highlights: ► Meso-TS-1 catalyst was synthesized using a SiO{sub 2}–TiO{sub 2} xerogel with an organosilane precursor. ► Hierarchical pore structure was confirmed by characterization of the materials. ► Catalytic activity was tested using oxidative desulfurization of the model sulfur compounds. ► Meso-TS-1 demonstrated significantly improved catalytic activity than TS-1. -- Abstract: Mesoporous TS-1 (M-TS-1) was synthesized using a hybrid SiO{sub 2}–TiO{sub 2} xerogel combined with an organosilane precursor. Prepared samples were characterized by XRD, UV–vis spectroscopy, SEM, and N{sub 2} adsorption–desorption measurement. M-TS-1, prepared in 2 days, showed high crystallinity and the best textural properties among the samples. The N{sub 2} adsorption–desorption isotherms of M-TS-1 exhibited a hysteresis loop at pressure higher than P/P{sub 0} = 0.4, clearly indicating the existence of mesopores. M-TS-1 has significantly larger mesopore volume (0.48 cm{sup 3}/g) than that of conventional TS-1 (0.07 cm{sup 3}/g), and showed a narrow peak centered at ca. 6.3 nm. In the oxidative desulfurization reaction, M-TS-1 was more active than conventional TS-1 at the same Ti-loading; M-TS-1 produced a dibenzothiophene (DBT) conversion of 96%, whereas conventional TS-1 produced a final DBT conversion of 5.6% after a reaction time of 180 min. Oxidative desulfurization over TS-1 was influenced both by electron density and steric hindrance in the sulfur compounds tested.

  4. Synthesis of mesoporous TS-1 using a hybrid SiO2–TiO2 xerogel for catalytic oxidative desulfurization

    International Nuclear Information System (INIS)

    Yang, Seung-Tae; Jeong, Kwang-Eun; Jeong, Soon-Yong; Ahn, Wha-Seung

    2012-01-01

    Graphical abstract: Display Omitted Highlights: ► Meso-TS-1 catalyst was synthesized using a SiO 2 –TiO 2 xerogel with an organosilane precursor. ► Hierarchical pore structure was confirmed by characterization of the materials. ► Catalytic activity was tested using oxidative desulfurization of the model sulfur compounds. ► Meso-TS-1 demonstrated significantly improved catalytic activity than TS-1. -- Abstract: Mesoporous TS-1 (M-TS-1) was synthesized using a hybrid SiO 2 –TiO 2 xerogel combined with an organosilane precursor. Prepared samples were characterized by XRD, UV–vis spectroscopy, SEM, and N 2 adsorption–desorption measurement. M-TS-1, prepared in 2 days, showed high crystallinity and the best textural properties among the samples. The N 2 adsorption–desorption isotherms of M-TS-1 exhibited a hysteresis loop at pressure higher than P/P 0 = 0.4, clearly indicating the existence of mesopores. M-TS-1 has significantly larger mesopore volume (0.48 cm 3 /g) than that of conventional TS-1 (0.07 cm 3 /g), and showed a narrow peak centered at ca. 6.3 nm. In the oxidative desulfurization reaction, M-TS-1 was more active than conventional TS-1 at the same Ti-loading; M-TS-1 produced a dibenzothiophene (DBT) conversion of 96%, whereas conventional TS-1 produced a final DBT conversion of 5.6% after a reaction time of 180 min. Oxidative desulfurization over TS-1 was influenced both by electron density and steric hindrance in the sulfur compounds tested.

  5. Cyclic voltammetry modeling of proton transport effects on redox charge storage in conductive materials: application to a TiO2 mesoporous film.

    Science.gov (United States)

    Kim, Y S; Balland, V; Limoges, B; Costentin, C

    2017-07-21

    Cyclic voltammetry is a particularly useful tool for characterizing charge accumulation in conductive materials. A simple model is presented to evaluate proton transport effects on charge storage in conductive materials associated with a redox process coupled with proton insertion in the bulk material from an aqueous buffered solution, a situation frequently encountered in metal oxide materials. The interplay between proton transport inside and outside the materials is described using a formulation of the problem through introduction of dimensionless variables that allows defining the minimum number of parameters governing the cyclic voltammetry response with consideration of a simple description of the system geometry. This approach is illustrated by analysis of proton insertion in a mesoporous TiO 2 film.

  6. 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.

  7. Promotion effect of palladium on Co{sub 3}O{sub 4} incorporated within mesoporous MCM-41 silica for CO Oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Hassan, Hassan M.A., E-mail: hassan.hassan@suezuniv.edu.eg [Department of Chemistry, Faculty of Science, Suez University, Suez (Egypt); Institut fur Anorganische Chemie und Strukturchemie, Heinrich-Heine Universitat, Dusseldorf (Germany); Betiha, Mohamed A. [Egyptian Petroleum Research Institute, Cairo 11727, Nasr City, Cairo (Egypt); Elshaarawy, Reda F.M. [Department of Chemistry, Faculty of Science, Suez University, Suez (Egypt); Institut fur Anorganische Chemie und Strukturchemie, Heinrich-Heine Universitat, Dusseldorf (Germany); Samy El-Shall, M. [Department of Chemistry, Virginia Commonwealth University Richmond, VA 23284-2006 (United States)

    2017-04-30

    Highlights: • Co{sub 3}O{sub 4} incorporated MCM-41 materials were successfully synthesized using MWI direct approach. • Co3{sup +} cation is considered as favorable site for CO adsorption resulted in promote the CO oxidation. • The loading of Pd species resulted in enhancement of activity for CO oxidation. - Abstract: Co{sub 3}O{sub 4} incorporated within mesoporous MCM-41 silica have been successfully synthesized and promoted with Pd nanoparticles through a microwave irradiation (MWI) approach. Powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), N{sub 2}-physisorped, X-ray photoelectron spectroscopy (XPS), temperature program reduction of hydrogen (H{sub 2}-TPR), temperature program desorption of oxygen (O{sub 2}-TPD) and high resolution transmission electron microscopy (HRTEM) were adapted to characterize these prepared catalysts. Carbon monoxide oxidation as a model reaction was then used to assess the catalytic performance of these materials. In the light of H{sub 2}-TPR and XPS results, revealed that the coexisting of Co{sup 3+} and Co{sup 2+} species as well as surface Co{sup 3+}/Co{sup 2+} ratio within the hexagonal mesoporous of MCM-41, could create an ideal environment to accomplish most extreme catalytic activity. On the other hand, the enhanced CO oxidation by Pd nanoparticles deposition has been explained in the light of the enhancement of the redox ability and tuning the electronic structure of Co{sub 3}O{sub 4}, which improved the O{sub 2} activation and reduced the adsorption ability of CO simultaneously, which significantly boosted the catalytic performance of CO oxidation. This work provides insights into factors that could lead to improved low temperature CO oxidation performance in Pd-based catalysts.

  8. Enhanced antibacterial activity of silver-decorated sandwich-like mesoporous silica/reduced graphene oxide nanosheets through photothermal effect

    Science.gov (United States)

    Liu, Rong; Wang, Xuandong; Ye, Jun; Xue, Ximei; Zhang, Fangrong; Zhang, Huicong; Hou, Xuemei; Liu, Xiaolong; Zhang, Yun

    2018-03-01

    Drug resistance of bacteria has become a global health problem, as it makes conventional antibiotics less efficient. It is urgently needed to explore novel antibacterial materials and develop effective treatment strategies to overcome the drug resistance of antibiotics. Herein, we successfully synthesized silver decorated sandwich-like mesoporous silica/reduced graphene oxide nanosheets (rGO/MSN/Ag) as a novel antibacterial material through facile method. The rGO and Ag nanoparticles can be reduced in the reaction system without adding any other reductants. In addition, the rGO/MSN/Ag showed higher photothermal conversion capacity due to the modification of silver nanoparticles and exhibited excellent antibacterial activities against Pseudomonas putida, Escherichia coli and Rhodococcus at relatively low dosages, which was confirmed by the minimum inhibitory concentration (MIC) test. Meanwhile, the E. coli with a high concentration was selected for exposure using an 808 nm laser, and the antibacterial effect was obviously enhanced by the near-infrared irradiation induced photothermal effect. Moreover, the hepatocyte LO2 were used for the cytotoxicity evaluation, and the rGO/MSN/Ag showed low toxicity and were without detectable cytotoxicity at the antimicrobial dose. As the prepared rGO/MSN/Ag nanosheets have the advantages of low-cost and high antibacterial activity, they might be of promising and useful antibacterial agents for different applications.

  9. Mesoporous Mn promoted Co3O4 oxides as an efficient and stable catalyst for low temperature oxidation of CO

    Science.gov (United States)

    Liu, Changxiang; Gong, Lei; Dai, Runying; Lu, Meijuan; Sun, Tingting; Liu, Qian; Huang, Xigen; Huang, Zhong

    2017-09-01

    Mesoporous Mn-doped Co3O4 catalysts were successfully prepared via a dry soft reactive grinding method based on solid state reaction, and their catalytic performances on CO oxidation were evaluated at a high space velocity of 49,500 mL g-1 h-1. A significant promoted effect was observed once the atomic ratios of Mn/(Co+Mn) were lower than 10%, for instance, the temperature for 50% conversion decreased to about -60 °C, showing superior catalytic performance compared to the single metal oxide. Especially, the Mn-promoted Co3O4 catalyst with a Mn/(Co+Mn) molar ratio of 10% could convert 100% CO after 3000 min of time-on-steam without any deactivation at room temperature. As prepared catalysts were characterized by XRD, N2-adsorption/desorption, TEM, H2-TPR, O2-TPD and CO-titration analysis. The significant enhancement of performance for oxidation of CO over Mn-Co-O mixed oxides was associated with the high active oxygen species concentrations formed during the pretreatment in O2 atmosphere.

  10. Desorption Kinetics and Mechanisms of CO2 on Amine-Based Mesoporous Silica Materials

    Directory of Open Access Journals (Sweden)

    Yang Teng

    2017-01-01

    Full Text Available Tetraethylenepentamine (TEPA-based mesoporous MCM-41 is used as the adsorbent to determine the CO2 desorption kinetics of amine-modified materials after adsorption. The experimental data of CO2 desorption as a function of time are derived by zero-length column at different temperatures (35, 50, and 70 °C and analyzed by Avrami’s fractional-order kinetic model. A new method is used to distinguish the physical desorption and chemical desorption performance of surface-modified mesoporous MCM-41. The activation energy Ea of CO2 physical desorption and chemical desorption calculated from Arrhenius equation are 15.86 kJ/mol and 57.15 kJ/mol, respectively. Furthermore, intraparticle diffusion and Boyd’s film models are selected to investigate the mechanism of CO2 desorption from MCM-41 and surface-modified MCM-41. For MCM-41, there are three rate-limiting steps during the desorption process. Film diffusion is more prominent for the CO2 desorption rates at low temperatures, and pore diffusion mainly governs the rate-limiting process under higher temperatures. Besides the surface reaction, the desorption process contains four rate-limiting steps on surface-modified MCM-41.

  11. 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.

  12. Cu(II) recognition materials: Fluorophores grafted on mesoporous silica supports

    International Nuclear Information System (INIS)

    Kledzik, Krzysztof; Orlowska, Maja; Patralska, Dorota; Gwiazda, Marcin; Jezierska, Julia; Pikus, Stanislaw; Ostaszewski, Ryszard; Klonkowski, Andrzej M.

    2007-01-01

    There were designed and synthesized naphthalene and pyrene derivatives consisting of fluorophore group and of receptor fragment with donor N and O atoms. These fluorosensors were covalently attached by grafting carboxyl group to surfaces of silica xerogel or mesoporous silicas (MCM-41 and MCM-48) functionalized either with 3-aminopropyl or 3-glycidoxypropyl groups. The pyrene derivatives 2 and 3 covalently grafted on MCM-48 silica functionalized with 3-aminopropyl groups are potential recognition elements of a fluorescence chemical sensor. Fluorescence emission of the prepared recognition materials is quenched specifically owing to photoinduced electron transfer (PET) effect after coordination reactions with Cu(II) ions. Moreover, both the materials exhibit selectivity for Cu(II) ions in aqueous solutions in presence of such metal ions as: alkali, alkaline earth and transition. During UV irradiation the studied recognition elements undergo slowly photochemical degradation

  13. Mesoporous nitrogen-rich carbon materials as cathode catalysts in microbial fuel cells

    KAUST Repository

    Ahn, Yongtae

    2014-12-01

    The high cost of the catalyst material used for the oxygen reduction reaction in microbial fuel cell (MFC) cathodes is one of the factors limiting practical applications of this technology. Mesoporous nitrogen-rich carbon (MNC), prepared at different temperatures, was examined as an oxygen reduction catalyst, and compared in performance to Pt in MFCs and electrochemical cells. MNC calcined at 800 °C produced a maximum power density of 979 ± 131 mW m-2 in MFCs, which was 37% higher than that produced using MNC calined at 600 °C (715 ± 152 mW m-2), and only 14% lower than that obtained with Pt (1143 ± 54 mW m-2). The extent of COD removal and coulombic efficiencies were the same for all cathode materials. These results show that MNC could be used as an alternative to Pt in MFCs. © 2014 Elsevier B.V. All rights reserved.

  14. Mesoporous electrode material from alumina-stabilized anatase TiO.sub.2./sub. for lithium ion batteries

    Czech Academy of Sciences Publication Activity Database

    Attia, Adel; Zukalová, Markéta; Rathouský, Jiří; Zukal, Arnošt; Kavan, Ladislav

    2005-01-01

    Roč. 9, č. 3 (2005), s. 134-145 ISSN 1432-8488 R&D Projects: GA ČR(CZ) GA203/03/0824 Institutional research plan: CEZ:AV0Z40400503 Keywords : titanium dioxide * alumina * lithium battery * mesoporous materials Subject RIV: CG - Electrochemistry Impact factor: 1.158, year: 2005

  15. A mini review of designed mesoporous materials for energy-storage applications: from electric double-layer capacitors to hybrid supercapacitors

    Science.gov (United States)

    Lim, Eunho; Jo, Changshin; Lee, Jinwoo

    2016-04-01

    In recent years, porous materials have attracted significant attention in various research fields because of their structural merits. In particular, well-designed mesoporous structures with two- or three-dimensionally interconnected pores have been recognized as electrode materials of particular interest for achieving high-performance electrochemical capacitors (ECs). In this mini review, recent progress in the design of mesoporous electrode materials for ECs, from electric double-layer capacitors (EDLCs) and pseudocapacitors (PCs) to hybrid supercapacitors (HSCs), and research challenges for the development of new mesoporous electrode materials has been discussed.

  16. Spectral studies on the interaction of acetylacetone with aluminum-containing MCM-41 mesoporous materials

    International Nuclear Information System (INIS)

    Zanjanchi, M.A.; Vaziri, M.

    2008-01-01

    Diffuse reflectance spectroscopy (DRS) was used to study the interaction of acetylacetone (acac) with the mesoporous aluminum-containing MCM-41 materials. A room temperature synthesis method was used for preparation of purely siliceous MCM-41 and for aluminum-containing MCM-41 materials. Samples with Si/Al ratios of 50, 20, 10 and 5 were synthesized. The synthesized mesoporous materials possess highly ordered structure and high surface area as evidenced from X-ray diffraction and nitrogen physisorption measurements, respectively. The treatment of the as-synthesized aluminum-containing MCM-41 samples with acac shows a distinct band at ∼290 nm. This band is assigned to six coordinated aluminum atoms in the structure which is produced by diffusion of acac molecules through surfactant micelles and their interaction with aluminum atoms. The 290-nm band disappears upon several successive washing of the sample with ethanol. The treatment of the calcined aluminum-containing MCM-41 sample with acac produces the same 290-nm band where its intensity increases with the aluminum content of the sample. The intensity of this band is reduced upon successive ethanol washing, but remains nearly constant after three times washing. This irremovable aluminum species can be assigned to framework aluminum. The measured acidity for our aluminum-containing MCM-41 samples correlates linearly with the intensity of 290-nm band for the ethanol treated samples. This supports the idea that the Bronsted acidity in aluminum-modified MCM-41 samples is a function of the amount of tetrahedral framework aluminum in the structure

  17. Natural material-decorated mesoporous silica nanoparticle container for multifunctional membrane-controlled targeted drug delivery

    Directory of Open Access Journals (Sweden)

    Hu Y

    2017-11-01

    Full Text Available Yan Hu,1 Lei Ke,2 Hao Chen,1 Ma Zhuo,1 Xinzhou Yang,1 Dan Zhao,1 Suying Zeng,1 Xincai Xiao1 1Department of Pharmaceutics, School of Pharmaceutical Science, South-Central University for Nationalities, 2Department of Medicinal Chemistry, School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, People’s Republic of China Abstract: To avoid the side effects caused by nonspecific targeting, premature release, weak selectivity, and poor therapeutic efficacy of current nanoparticle-based systems used for drug delivery, we fabricated natural material-decorated nanoparticles as a multifunctional, membrane-controlled targeted drug delivery system. The nanocomposite material coated with a membrane was biocompatible and integrated both specific tumor targeting and responsiveness to stimulation, which improved transmission efficacy and controlled drug release. Mesoporous silica nanoparticles (MSNs, which are known for their biocompatibility and high drug-loading capacity, were selected as a model drug container and carrier. The membrane was established by the polyelectrolyte composite method from chitosan (CS which was sensitive to the acidic tumor microenvironment, folic acid-modified CS which recognizes the folate receptor expressed on the tumor cell surface, and a CD44 receptor-targeted polysaccharide hyaluronic acid. We characterized the structure of the nanocomposite as well as the drug release behavior under the control of the pH-sensitive membrane switch and evaluated the antitumor efficacy of the system in vitro. Our results provide a basis for the design and fabrication of novel membrane-controlled nanoparticles with improved tumor-targeting therapy. Keywords: multifunctional, membrane-controlled, natural materials, mesoporous silica nanoparticles, targeted drug delivery

  18. 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.

  19. Fabrication of Nitrogen-Doped Mesoporous-Carbon-Coated Palladium Nanoparticles: An Intriguing Electrocatalyst for Methanol and Formic Acid Oxidation.

    Science.gov (United States)

    Ray, Chaiti; Dutta, Soumen; Sahoo, Ramkrishna; Roy, Anindita; Negishi, Yuichi; Pal, Tarasankar

    2016-05-20

    Inspired by the attractive catalytic properties of palladium and the inert nature of carbon supports in catalysis, a concise and simple methodology for in situ nitrogen-doped mesoporous-carbon-supported palladium nanoparticles (Pd/N-C) has been developed by carbonizing a palladium dimethylglyoximate complex. The as-synthesized Pd/N-C has been exfoliated as a fuel cell catalyst by studying the electro-oxidation of methanol and formic acid. The material synthesized at 400 °C,namely, Pd/N-C-400,exhibitssuperior mass activity and stability among catalysts synthesized under different carbonization temperaturesbetween300 and 500 °C. The unique 1D porous structure in Pd/N-C-400 helps better electron transport at the electrode surface, which eventually leads to about five times better catalytic activity and about two times higher stability than that of commercial Pd/C. Thus, our designed sacrificial metal-organic templatedirected pathway becomes a promising technique for Pd/N-C synthesis with superior catalytic performances. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Preparation and characterization of mesoporous VO(x)-TiO2 complex oxides for the selective oxidation of methanol to dimethoxymethane.

    Science.gov (United States)

    Liu, Jingwei; Sun, Qing; Fu, Yuchuan; Shen, Jianyi

    2009-07-15

    Mesoporous VO(x)-TiO(2) with high surface areas were prepared using the procedure of evaporation-induced self-assembly combined with ammonia posttreatment. The samples were characterized by X-ray diffraction (XRD), laser Raman spectroscopy (LRS), transmission electron microscopy (TEM), N(2) adsorption, temperature-programmed reduction (H(2)-TPR), microcalorimetry for the adsorption of NH(3), and isopropanol probe reaction. Their catalytic activities were evaluated for the reaction of selective oxidation of methanol to dimethoxymethane (DMM). It was found that the VO(x)-TiO(2) materials exhibited high surface areas with pore diameters of 4 nm. The vanadia species were highly dispersed in the VO(x)-TiO(2) within 30 wt% VO(x) content, evidenced by the results of XRD and LRS. The VO(x)-TiO(2) samples exhibited both surface acidic and redox properties. The surface acidity was further enhanced on the addition of SO(4)2-. The catalyst SO(4)2-/30VO(x)-TiO(2) exhibited good performance for the selective oxidation of methanol (57% conversion) to DMM (83% selectivity) at 423 K.

  1. Facile and tunable synthesis of hierarchical mesoporous silica materials ranging from flower structure with wrinkled edges to hollow structure with coarse surface

    Energy Technology Data Exchange (ETDEWEB)

    Hao, Nanjing, E-mail: nanjing.hao@dartmouth.edu [Dartmouth College, Thayer School of Engineering (United States); Li, Laifeng; Tang, Fangqiong, E-mail: tangfq@mail.ipc.ac.cn [Chinese Academy of Sciences, Technical Institute of Physics and Chemistry (China)

    2016-11-15

    Mesoporous silica materials have attracted great attention in many fields. However, facile and tunable synthesis of hierarchical mesoporous silica structures is still a big challenge, and thus the development of them still lags behind. Herein, well-defined mesoporous silica flower structure with wrinkled edges and mesoporous silica hollow structure with coarse surface were synthesized simply by using poly(vinylpyrrolidone) and hexadecylamine as cotemplates in different water/ethanol solvent systems. The shape evolution from flower to hollow can be easily realized by tuning the volume ratio of water to ethanol, and the yields of both materials can reach gram scale. The formation mechanisms of mesoporous silica flower and hollow structures were also experimentally investigated and discussed. These novel hierarchical structures having unique physicochemical properties may bring many interesting insights into scientific research and technological application.

  2. Mesoporous titanium phosphates and related molecular sieves ...

    Indian Academy of Sciences (India)

    Unknown

    phosphate using a dilute H2O2 oxidant supports the tetrahedral coordination of Ti in ... production of H2 by photo-reduction of water under UV light irradiation. ... have been extensively studied and used as acid catalysts, adsorbents and ion ... mesoporous silica materials is also of outstanding interest because of their ...

  3. Preparation of Pt-mesoporous tungsten carbide/carbon composites via a soft-template method for electrochemical methanol oxidation

    International Nuclear Information System (INIS)

    Ma, Chun’an; Kang, Lingzhi; Shi, Meiqin; Lang, Xiaoling; Jiang, Yekun

    2014-01-01

    Highlights: • Mesoporous composite Pt-m(WC/C) is prepared by a soft template method. • The structure of phenolic gives a space limitation effect on the growth of WC. • Analysis of the effect of F127 on controlling the structure of composites. • Pt-m(WC/C) exhibits more than three times higher than Pt/C in catalytic activity. -- Abstract: This paper introduces a simple and reproducible chemical process for synthesis of Pt-mesoporous tungsten carbide/carbon composites composites Pt-m(WC/C) by means of a soft-template method. In this process, low-molecular-weight phenolic resol acted as the precursor both for carbon support and also the carbon resource of tungsten carbide. Tungsten hexachloride was used as a tungsten precursor along with different amount of triblock copolymer Pluronic F127 as pore-forming component. The best performance of Pt-m(WC/C) towards methanol oxidation is found when the mass ratios of WCl 6 :F127 is 1:0.6. The composite presents an improved methanol oxidation performance evidenced by a negative shift in onset potential, and increase of peak current density, compared with commercial Pt/C. The difference is explained by the adding of appropriate amount of F127 which facilitates the construction of mesoporous matrix structure of WC/C

  4. Preparation of Pt-mesoporous tungsten carbide/carbon composites via a soft-template method for electrochemical methanol oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Chun’an, E-mail: science@zjut.edu.cn; Kang, Lingzhi; Shi, Meiqin; Lang, Xiaoling; Jiang, Yekun

    2014-03-05

    Highlights: • Mesoporous composite Pt-m(WC/C) is prepared by a soft template method. • The structure of phenolic gives a space limitation effect on the growth of WC. • Analysis of the effect of F127 on controlling the structure of composites. • Pt-m(WC/C) exhibits more than three times higher than Pt/C in catalytic activity. -- Abstract: This paper introduces a simple and reproducible chemical process for synthesis of Pt-mesoporous tungsten carbide/carbon composites composites Pt-m(WC/C) by means of a soft-template method. In this process, low-molecular-weight phenolic resol acted as the precursor both for carbon support and also the carbon resource of tungsten carbide. Tungsten hexachloride was used as a tungsten precursor along with different amount of triblock copolymer Pluronic F127 as pore-forming component. The best performance of Pt-m(WC/C) towards methanol oxidation is found when the mass ratios of WCl{sub 6}:F127 is 1:0.6. The composite presents an improved methanol oxidation performance evidenced by a negative shift in onset potential, and increase of peak current density, compared with commercial Pt/C. The difference is explained by the adding of appropriate amount of F127 which facilitates the construction of mesoporous matrix structure of WC/C.

  5. 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.

  6. 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.

  7. The impact of framework organic functional groups on the hydrophobicity and overall stability of mesoporous silica materials

    International Nuclear Information System (INIS)

    Smeulders, Geert; Meynen, Vera; Silvestre-Albero, Ana; Houthoofd, Kristof; Mertens, Myrjam; Silvestre-Albero, Joaquin; Martens, Johan A.; Cool, Pegie

    2012-01-01

    Graphical abstract: The stability (hydrothermal, mechanical and chemical) of PMOs is studied in a systematic way and ranks them between classic and other hybrid mesoporous silica materials. Highlights: ► The stability (hydrothermal, mechanical and chemical) of PMOs is studied. ► Compared stability of PMOs with classic and other hybrid mesoporous silica materials. ► Immersion calorimetry to study the effect of hydrophobicity. ► PMOs show superior stability. - Abstract: The hydrothermal, mechanical and chemical stability of various mesoporous materials have been studied in detail, using X-ray diffraction and nitrogen sorption. Pure siliceous nanoporous powders (MCM-41 and SBA-15) are evaluated against their hybrid counterparts; namely 2 types of periodic mesoporous organosilicas (benzene and ethane bridged PMOs) and an organosilane grafted MCM-41 material. In primary tests, the stability of the hybrid materials is found to be superior compared to that of the pure siliceous ones. The stability of the materials was correlated to their hydrophobicity via immersion calorimetry, applied for the first time in this context. Based on these results, a clear correlation between the hydrophobicity of a material and its stability has been revealed. In addition, with 29 Si-MAS-NMR and vacuum experiments, the mechanism of the structural deterioration in the three different stability treatments could be unambiguously identified as the hydrolyzation of the siloxane bonds. The homogeneity of the hydrophobic groups throughout the entire network was found to be of great importance, irrespective of the hydrophobic nature at the surface as determined by calorimetric measurements. The results reveal that the most stable material can withstand (a) a pressure of 740 MPa during 5 min, (b) a 2 h stirring in a 2 M NaOH solution and (c) a 3 day steaming treatment at 393 K.

  8. The impact of framework organic functional groups on the hydrophobicity and overall stability of mesoporous silica materials

    Energy Technology Data Exchange (ETDEWEB)

    Smeulders, Geert, E-mail: geert.smeulders@ua.ac.be [University of Antwerpen (Ukraine), Laboratory of Adsorption and Catalysis, Universiteitsplein 1, 2610 Wilrijk (Belgium); Meynen, Vera [University of Antwerpen (Ukraine), Laboratory of Adsorption and Catalysis, Universiteitsplein 1, 2610 Wilrijk (Belgium); Silvestre-Albero, Ana [Universidad de Alicante, Laboratorio de Materiales Avanzados, Apartado 99, 03080 Alicante (Spain); Houthoofd, Kristof [KULeuven, Centre for Surface Chemistry and Catalysis, Kasteelpark Arenberg 23, 3001 Heverlee (Belgium); Mertens, Myrjam [Flemish Institute for Technological Research (VITO N.V.), Boeretang 200, 2400 Mol (Belgium); Silvestre-Albero, Joaquin [Universidad de Alicante, Laboratorio de Materiales Avanzados, Apartado 99, 03080 Alicante (Spain); Martens, Johan A. [KULeuven, Centre for Surface Chemistry and Catalysis, Kasteelpark Arenberg 23, 3001 Heverlee (Belgium); Cool, Pegie [University of Antwerpen (Ukraine), Laboratory of Adsorption and Catalysis, Universiteitsplein 1, 2610 Wilrijk (Belgium)

    2012-02-15

    Graphical abstract: The stability (hydrothermal, mechanical and chemical) of PMOs is studied in a systematic way and ranks them between classic and other hybrid mesoporous silica materials. Highlights: Black-Right-Pointing-Pointer The stability (hydrothermal, mechanical and chemical) of PMOs is studied. Black-Right-Pointing-Pointer Compared stability of PMOs with classic and other hybrid mesoporous silica materials. Black-Right-Pointing-Pointer Immersion calorimetry to study the effect of hydrophobicity. Black-Right-Pointing-Pointer PMOs show superior stability. - Abstract: The hydrothermal, mechanical and chemical stability of various mesoporous materials have been studied in detail, using X-ray diffraction and nitrogen sorption. Pure siliceous nanoporous powders (MCM-41 and SBA-15) are evaluated against their hybrid counterparts; namely 2 types of periodic mesoporous organosilicas (benzene and ethane bridged PMOs) and an organosilane grafted MCM-41 material. In primary tests, the stability of the hybrid materials is found to be superior compared to that of the pure siliceous ones. The stability of the materials was correlated to their hydrophobicity via immersion calorimetry, applied for the first time in this context. Based on these results, a clear correlation between the hydrophobicity of a material and its stability has been revealed. In addition, with {sup 29}Si-MAS-NMR and vacuum experiments, the mechanism of the structural deterioration in the three different stability treatments could be unambiguously identified as the hydrolyzation of the siloxane bonds. The homogeneity of the hydrophobic groups throughout the entire network was found to be of great importance, irrespective of the hydrophobic nature at the surface as determined by calorimetric measurements. The results reveal that the most stable material can withstand (a) a pressure of 740 MPa during 5 min, (b) a 2 h stirring in a 2 M NaOH solution and (c) a 3 day steaming treatment at 393 K.

  9. Shape-Enhanced Photocatalytic Activities of Thoroughly Mesoporous ZnO Nanofibers

    KAUST Repository

    Ren, Xiaolong; Hou, Huilin; Liu, Zhixiong; Gao, Fengmei; Zheng, Jinju; Wang, Lin; Li, Wenge; Ying, Pengzhan; Yang, Weiyou; Wu, Tao

    2016-01-01

    1D mesoporous materials have attracted extensive interest recently, owning to their fascinating properties and versatile applications. However, it remains as a grand challenge to develop a simple and efficient technique to produce oxide nanofibers

  10. 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.

  11. Synthesis, Characterization and Application of the novel, regular mesoporous materials MCM-41 and MCM-48

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, R

    1995-07-01

    In the application of zeolites to catalytic cracking of heavy oil fractions the need of regular solids with large pore sizes has become very obvious. The scope of this thesis was to synthesize and characterize the novel mesoporous materials MCM-41 and MCM-48 with the major emphasis laid on MCM-41. MCM-41 materials with bulk Si/Al ratios of 4, 9, 18 and {infinity} were synthesized and characterized by XRD and HREM. The catalytic cracking behaviour of Al-containing MCM-41 materials was investigated by pulse reactor studies using decalin as model feed and by Micro Activity Tests using atmospheric residue or n-hexadecane as feed. Aluminium containing MCM-41 was found to be active for the cracking of heavy oil fractions. Purely siliceous MCM-41 materials with pore sizes ranging from 18 Aa to 40 Aa were synthesized and their properties studied by means of NMR spectroscopy. The MCM-48, which is a cubic member of the M41S family with a three dimensional pore system, was studied by means of a combination of X-ray powder diffraction and HREM technique. 210 refs., 76 figs., 9 tabs.

  12. Mesoporous Nickel Oxide (NiO) Nanopetals for Ultrasensitive Glucose Sensing

    Science.gov (United States)

    Mishra, Suryakant; Yogi, Priyanka; Sagdeo, P. R.; Kumar, Rajesh

    2018-01-01

    Glucose sensing properties of mesoporous well-aligned, dense nickel oxide (NiO) nanostructures (NSs) in nanopetals (NPs) shape grown hydrothermally on the FTO-coated glass substrate has been demonstrated. The structural study based investigations of NiO-NPs has been carried out by X-ray diffraction (XRD), electron and atomic force microscopies, energy dispersive X-ray (EDX), and X-ray photospectroscopy (XPS). Brunauer-Emmett-Teller (BET) measurements, employed for surface analysis, suggest NiO's suitability for surface activity based glucose sensing applications. The glucose sensor, which immobilized glucose on NiO-NPs@FTO electrode, shows detection of wide range of glucose concentrations with good linearity and high sensitivity of 3.9 μA/μM/cm2 at 0.5 V operating potential. Detection limit of as low as 1 μΜ and a fast response time of less than 1 s was observed. The glucose sensor electrode possesses good anti-interference ability, stability, repeatability & reproducibility and shows inert behavior toward ascorbic acid (AA), uric acid (UA) and dopamine acid (DA) making it a perfect non-enzymatic glucose sensor.

  13. Hexagonal mesoporous titanosilicates as support for vanadium oxide-Promising catalysts for the oxidative dehydrogenation of n-butane

    Czech Academy of Sciences Publication Activity Database

    Setnička, M.; Čičmanec, P.; Bulánek, R.; Zukal, Arnošt; Pastva, Jakub

    2013-01-01

    Roč. 204, APR 2013 (2013), s. 132-139 ISSN 0920-5861 R&D Projects: GA ČR GAP106/10/0196 Institutional support: RVO:61388955 Keywords : mesoporous titanosilicate * hexagonal mesoporous structure * vanadium Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.309, year: 2013

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

    Energy Technology Data Exchange (ETDEWEB)

    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.)

  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. 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.

  17. 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.

  18. Degradability and Clearance of Silicon, Organosilica, Silsesquioxane, Silica Mixed Oxide, and Mesoporous Silica Nanoparticles

    KAUST Repository

    Croissant, Jonas G.; Fatieiev, Yevhen; Khashab, Niveen M.

    2017-01-01

    The biorelated degradability and clearance of siliceous nanomaterials have been questioned worldwide, since they are crucial prerequisites for the successful translation in clinics. Typically, the degradability and biocompatibility of mesoporous

  19. Synthesis and electrochemical performance of mesoporous SiO{sub 2}–carbon nanofibers composite as anode materials for lithium secondary batteries

    Energy Technology Data Exchange (ETDEWEB)

    Hyun, Yura; Choi, Jin-Yeong [Department of Chemistry, Keimyung University (Korea, Republic of); Park, Heai-Ku [Department of Chemical Engineering, Keimyung University (Korea, Republic of); Bae, Jae Young [Department of Chemistry, Keimyung University (Korea, Republic of); Lee, Chang-Seop, E-mail: surfkm@kmu.ac.kr [Department of Chemistry, Keimyung University (Korea, Republic of)

    2016-10-15

    Highlights: • Mesoporous SiO{sub 2}–carbon nanofibers composite synthesized on Ni foam without any binder. • This composite was directly applied as anode material of Li secondary batteries. • Showed the highest initial (2420 mAh/g) and discharging (2092 mAh/g) capacity. • This material achieved a retention rate of 86.4% after 30 cycles. - Abstract: In this study, carbon nanofibers (CNFs) and mesoporous SiO{sub 2}–carbon nanofibers composite were synthesized and applied as the anode materials in lithium secondary batteries. CNFs and mesoporous SiO{sub 2}–CNFs composite were grown via chemical vapor deposition method with iron-copper catalysts. Mesoporous SiO{sub 2} materials were prepared by sol–gel method using tetraethylorthosilicate as the silica source and cetyltrimethylammoniumchloride as the template. Ethylene was used as the carbon source and passes into a quartz reactor of a tube furnace heated to 600 °C, and the temperature was maintained at 600 °C for 10 min to synthesize CNFs and mesoporous SiO{sub 2}–CNFs composite. The electrochemical characteristics of the as-prepared CNFs and mesoporous SiO{sub 2}–CNFs composite as the anode of lithium secondary batteries were investigated using a three-electrode cell. In particular, the mesoporous SiO{sub 2}–CNFs composites synthesized without binder after depositing mesoporous SiO{sub 2} on Ni foam showed the highest charging and discharging capacity and retention rate. The initial capacity (2420 mAh/g) of mesoporous SiO{sub 2}–CNFs composites decreased to 2092 mAh/g after 30 cycles at a retention rate of 86.4%.

  20. Structural and magnetic properties of the nanocomposite materials based on a mesoporous silicon dioxide matrix

    Energy Technology Data Exchange (ETDEWEB)

    Grigor’eva, N. A., E-mail: natali@lns.pnpi.spb.ru [St. Petersburg State University (Russian Federation); Eckerlebe, H. [Helmholtz-Zentrum Geesthacht (Germany); Eliseev, A. A.; Lukashin, A. V.; Napol’skii, K. S. [Moscow State University (Russian Federation); Kraje, M. [Reactor Institute Delft (Netherlands); Grigor’ev, S. V. [St. Petersburg State University (Russian Federation)

    2017-03-15

    The structural and magnetic properties of the mesoporous systems based on silicon dioxide with a regular hexagonal arrangement of pores several microns in length and several nanometers in diameter, which are filled with iron compound nanofilaments in various chemical states, are studied in detail. The studies are performed using the following mutually complementary methods: transmission electron microscopy, SQUID magnetometry, electron spin resonance, Mössbauer spectroscopy, polarized neutron small-angle diffraction, and synchrotron radiation diffraction. It is shown that the iron nanoparticles in pores are mainly in the γ phase of Fe{sub 2}O{sub 3} with a small addition of the α phase and atomic iron clusters. The effective magnetic field acting on a nanofilament from other nanofilaments is 11 mT and has a dipole nature, the ferromagnetic–paramagnetic transition temperature is in the range 76–94 K depending on the annealing temperature of the samples, and the temperature that corresponds to the change in the magnetic state of the iron oxide nanofilaments is T ≈ 50–60 K at H = 0 and T ≈ 80 K at H = 300 mT. It is also shown that the magnetization reversal of an array of nanofilaments is caused by the magnetostatic interaction between nanofilaments at the fields that are lower than the saturation field.

  1. Mesoporous ethanesilica materials with bimodal and trimodal pore-size distributions synthesised in the presence of cobalt ions

    Directory of Open Access Journals (Sweden)

    Alufelwi M. Tshavhungwe

    2010-07-01

    Full Text Available Mesoporous organosilica materials containing ethane groups in their framework were formed with two and three pore sizes (i.e. bimodal and trimodal pores when synthesised by the sol-gel method in the presence of cobalt ions. The compounds 1,2-bistrimethoxysilylethane and tetraethylorthosilicate were used as silicon sources and the reactions were done in the presence of a surfactant, which served as a template. Diffuse reflectance infrared Fourier transform spectroscopy revealed that organic functional groups were incorporated into the ethanesilica. Powder X-ray diffraction and nitrogen adsorption data indicated that the mesophase and textural properties (surface area, pore volume, pore diameter of the materials were dependent on the ageing temperature, the amount/ratio of silica precursors and cobalt ion incorporation. Secondary mesopores were drastically reduced by changing the ratio of silicon precursors.

  2. Solvothermal synthesis and enhanced CO2 adsorption ability of mesoporous graphene oxide-ZnO nanocomposite

    International Nuclear Information System (INIS)

    Li, Weidong; Jiang, Xia; Yang, Huayun; Liu, Qi

    2015-01-01

    Highlights: • GO–ZnO nanocomposite was prepared by solvothermal method. • Several technologies have been used to ensure and analyze the composite. • GO–ZnO has CO 2 adsorption capacity of up to 44.8 cm 3 /g at 298 K and 1 bar. • The composite has excellent adsorption/desorption recycling ability. - Abstract: Mesoporous graphene oxide–ZnO (GO–ZnO) nanocomposite has been synthesized by GO and ZnO which was prepared by solvothermal method. Power X-ray diffraction (PXRD), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) have been used to characterize the structure and morphology of the porous GO–ZnO hybrid. With visible porosity of ZnO and GO–ZnO, N 2 adsorption–desorption measurements and pore size analysis have been investigated and compared. Comparing to ZnO, GO–ZnO showed larger Brunauer–Emmett–Teller (BET) surface area and enhanced ability on capturing CO 2 at different temperatures. Several cycles of adsorption–desorption experiments on CO 2 have been tested and it proved GO–ZnO to be potential adsorbent material with excellent cycling stability.

  3. 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.

  4. 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

  5. Synthesis and characterization of alkyl-imidazolium-based periodic mesoporous organosilicas: a versatile host for the immobilization of perruthenate (RuO4-) in the aerobic oxidation of alcohols.

    Science.gov (United States)

    Karimi, Babak; Elhamifar, Dawood; Yari, Omolbanin; Khorasani, Mojtaba; Vali, Hojatollah; Clark, James H; Hunt, Andrew J

    2012-10-15

    The preparation and characterization of a set of periodic mesoporous organosilicas (PMOs) that contain different fractions of 1,3-bis(3-trimethoxysilylpropyl)imidazolium chloride (BTMSPI) groups uniformly distributed in the silica mesoporous framework is described. The mesoporous structure of the materials was characterized by powder X-ray diffraction, transmission electron microscopy, and N(2) adsorption-desorption analysis. The presence of propyl imidazolium groups in the silica framework of the materials was also characterized by solid-state NMR spectroscopy and diffuse-reflectance Fourier-transform infrared spectroscopy. The effect of the BTMSPI concentration in the initial solutions on the structural properties (including morphology) of the final materials was also examined. The total organic content of the PMOs was measured by elemental analysis, whereas their thermal stability was determined by thermogravimetric analysis. Among the described materials, it was found that PMO with 10% imidazolium content is an effective host for the immobilization of perruthenate through an ion-exchange protocol. The resulting Ru@PI-10 was then employed as a recyclable catalyst in the highly efficient aerobic oxidation of various types of alcohols. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Outstanding low temperature HC-SCR of NOx over platinum-group catalysts supported on mesoporous materials expecting diesel-auto emission regulation

    International Nuclear Information System (INIS)

    Komatsu, Tamikuni; Tomokuni, Keizou; Yamada, Issaku

    2006-01-01

    Outstanding low temperature HC-SCR of NOx over platinum-group catalysts supported on mesoporous materials, which does not rely on the conventional NOx-absorption-reduction-catalysts, is presented for the purpose of de-NOx of diesel-auto emissions. The established catalysts basically consist of mesoporous silica or metal-substituted mesoporous silicates for supports and platinum for active species, which is operated under lean- and rich-conditions. The new catalysts are very active at 150-200 o C and free from difficult problems of SOx-deactivation and hydrothermal ageing of the NOx-absorption-reduction catalyst. (author)

  7. Substrate dependent self-organization of mesoporous cobalt oxide nanowires with remarkable pseudocapacitance

    KAUST Repository

    Baby, Rakhi Raghavan

    2012-05-09

    A scheme of current collector dependent self-organization of mesoporous cobalt oxide nanowires has been used to create unique supercapacitor electrodes, with each nanowire making direct contact with the current collector. The fabricated electrodes offer the desired properties of macroporosity to allow facile electrolyte flow, thereby reducing device resistance and nanoporosity with large surface area to allow faster reaction kinetics. Co 3O 4 nanowires grown on carbon fiber paper collectors self-organize into a brush-like morphology with the nanowires completely surrounding the carbon microfiber cores. In comparison, Co 3O 4 nanowires grown on planar graphitized carbon paper collectors self-organize into a flower-like morphology. In three electrode configuration, brush-like and flower-like morphologies exhibited specific capacitance values of 1525 and 1199 F/g, respectively, at a constant current density of 1 A/g. In two electrode configuration, the brush-like nanowire morphology resulted in a superior supercapacitor performance with high specific capacitances of 911 F/g at 0.25 A/g and 784 F/g at 40 A/g. In comparison, the flower-like morphology exhibited lower specific capacitance values of 620 F/g at 0.25 A/g and 423 F/g at 40 A/g. The Co 3O 4 nanowires with brush-like morphology exhibited high values of specific power (71 kW/kg) and specific energy (81 Wh/kg). Maximum energy and power densities calculated for Co 3O 4 nanowires with flower-like morphology were 55 Wh/kg and 37 kW/kg respectively. Both electrode designs exhibited excellent cycling stability by retaining ∼91-94% of their maximum capacitance after 5000 cycles of continuous charge-discharge. © 2012 American Chemical Society.

  8. Tuning the acidity of niobia: Characterization and catalytic activity of Nb2O5–MeO2 (Me = Ti, Zr, Ce) mesoporous mixed oxides

    International Nuclear Information System (INIS)

    Stošić, Dušan; Bennici, Simona; Pavlović, Vladimir; Rakić, Vesna; Auroux, Aline

    2014-01-01

    Mesoporous Nb 2 O 5 –MeO 2 (Me = Ti, Zr, Ce) mixed oxides were successfully prepared using evaporation-induced self-assembly (EISA) method. The structural and textural properties of these materials have been fully characterized using appropriate techniques (low-temperature adsorption–desorption of nitrogen, thermogravimetric analysis, X-ray diffraction analysis (XRD) transmission electron microscopy (TEM), scanning electron microscopy (SEM) and Raman spectroscopy). Acid–base properties were estimated by adsorption microcalorimetry of NH 3 and SO 2 molecules in order to determine the population, strength and strength distribution of acidic or basic sites. Formation of mesoporous structure was confirmed by the results of XRD, TEM and BET techniques. Results of adsorption microcalorimetry technique showed that the type of transition metal oxide added to niobia has a decisive role for acidic-basic character of investigated mixed oxides. Among the investigated mixed oxide formulations only Nb 2 O 5 –CeO 2 was amphoteric, while the other samples showed prominent acidic character. All the investigated materials are catalytically active in fructose dehydration; conversion of fructose and selectivity to 5-hydroxymethylfurfural (5-HMF) and levulinic acid (LA) are proved to be dependant on the number of acidic sites on the surface of catalysts. Furthermore, presence of the basic sites on the surface of the catalyst decreases the activity in the fructose dehydration reaction, as in the case of Nb 2 O 5 –CeO 2 sample. - Highlights: • Mesoporous Nb 2 O 5 –MeO 2 mixed oxides were successfully prepared by EISA method. • Acidic–basic properties depend on the nature of the oxide that was mixed with niobia. • Catalytic activity was tested in fructose dehydration in aqueous phase. • Selectivity and conversion in reaction are correlated to the number of acid sites

  9. 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.

  10. Effect of mesoporous g-C3N4 substrate on catalytic oxidation of CO over Co3O4

    Science.gov (United States)

    Yang, Heng; Lv, Kangle; Zhu, Junjiang; Li, Qin; Tang, Dingguo; Ho, Wingkei; Li, Mei; Carabineiro, Sónia A. C.

    2017-04-01

    Mesoporous graphitic carbon nitride (mpg-CN) was synthesized using Triton X-100, a surfactant containing a hydrophilic polyethylene oxide group and a tert-octyl-phenyl hydrophobic moiety, as a soft template. The obtained mpg-CN was used as a support for Co3O4, and this supported catalyst was used for CO oxidation. The effects of the amount of Triton X-100, weight ratio of Co3O4 to mpg-CN and calcination temperature on the catalytic performances for CO oxidation of Co3O4/mpg-CN composites were systematically studied. It was found that the presence of Triton X-100 not only retarded the polymerization of dicyandiamide, but also affected the microstructure of Co3O4. Bubbles formed because of the hydrophobic group of the surfactant Triton X-100 can be act as a soft template for the synthesis of mesoporous g-C3N4. The enhanced catalytic activity of Co3O4/mpg-CN was attributed to a synergistic effect, enlarged BET surface areas, increased Co3+ and lattice oxygen contents, and the porous structure of mpg-CN support. The high stability of 12.5% Co3O4/mpg-CN(1.0) makes it a promising catalyst for practical applications.

  11. Direct Synthesis of Methanol by Partial Oxidation of Methane with Oxygen over Cobalt Modified Mesoporous H-ZSM-5 Catalyst

    Directory of Open Access Journals (Sweden)

    Yuni Krisyuningsih Krisnandi

    2015-11-01

    Full Text Available Partial oxidation of methane over mesoporous catalyst cobalt modified H-ZSM-5 has been carried out. Mesoporous Na-ZSM-5 (Si/Al = 35.4 was successfully synthesized using double template method which has high surface area (450 m2/g and average pore diameter distribution of 1.9 nm. The as-synthesized Na-ZSM-5 was converted to H-ZSM-5 through multi-exchange treatment with ammonium ion solution, causing decreased crystallinity and surface area, but increased porous diameter, due to dealumination during treatment process. Moreover, H-ZSM-5 was loaded with cobalt (Co = 2.5% w by the incipient impregnation method and calcined at 550 °C. Partial oxidation of methane was performed in the batch reactor with 0.75 bar methane and 2 bar of nitrogen (with impurities of 0.5% oxygen as the input at various reaction time (30, 60 and 120 min. The reaction results show that cobalt species in catalyst has an important role, because H-ZSM-5 cannot produce methanol in partial oxidation of methane. The presence of molecular oxygen increased the percentage of methanol yield. The reaction is time-dependent with the highest methanol yield (79% was acquired using Co/H-ZSM-5 catalyst for 60 min.

  12. Synthesis of Hydrophobic Mesoporous Material MFS and Its Adsorption Properties of Water Vapor

    Directory of Open Access Journals (Sweden)

    Guotao Zhao

    2014-01-01

    Full Text Available Fluorine-containing hydrophobic mesoporous material (MFS with high surface area is successfully synthesized with hydrothermal synthesis method by using a perfluorinated surfactant SURFLON S-386 template. The adsorption properties of water vapor on the synthesized MFS are also investigated by using gravimetric method. Results show that SEM image of the MFS depicted roundish morphology with the average crystal size of 1-2 μm. The BET surface area and total pore volume of the MFS are 865.4 m2 g−1 and 0.74 cm3 g−1 with a narrow pore size distribution at 4.9 nm. The amount of water vapor on the MFS is about 0.41 mmol g−1 at 303 K, which is only 52.6% and 55.4% of MCM-41 and SBA-15 under the similar conditions, separately. The isosteric adsorption heat of water on the MFS is gradually about 27.0–19.8 kJ mol−1, which decreases as the absorbed water vapor amount increases. The value is much smaller than that on MCM-41 and SBA-15. Therefore, the MFS shows more hydrophobic surface properties than the MCM-41 and SBA-15. It may be a kind of good candidate for adsorption of large molecule and catalyst carrier with high moisture resistance.

  13. Heat storage properties of organic phase-change materials confined in the nanospace of mesoporous SBA-15 and CMK-3.

    Science.gov (United States)

    Kadoono, Tomosuke; Ogura, Masaru

    2014-03-28

    A novel type of material encapsulating phase-change materials (PCMs) is reported concerning their implication for use as thermal energy storage devices. The composites of siliceous SBA-15 or carbonaceous CMK-3 mesoporous assemblies and organic PCMs could be used to make leak-free devices that retain their capabilities over many thermal cycles for heat storage/release. A confinement effect was observed that alters the thermal properties of the encapsulated PCM, especially in CMK-3 without any similar effects in other carbon materials.

  14. Synthesis and characterization of silica mesoporous material produced by hydrothermal continues pH adjusting path way

    Directory of Open Access Journals (Sweden)

    A. Salemi Golezani

    2016-08-01

    Full Text Available Mesoporous silica molecular sieves MCM-41 were synthesized under hydrothermal conditions. For this purpose, a solution with a molar coefficient of water, cetyltri-methyl ammonium bromide surfactants as template and sodium silicate as the source of SiO2 are used. Phase formation, morphology and gas absorption properties were investigated by XRD and BET analysis, respectively. The results showed that silica mesoporous material has been successfully synthesized. A favorable special surface and porosity volume together with regular arrangement of nano metric-hexagonal porosities were obtained from this synthesis. Thickness of the wall and average diameter of the pores are 0.8 nm and 4 nm, respectively.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. Mesoporous Tin-Based Oxide Nanospheres/Reduced Graphene Composites as Advanced Anodes for Lithium-Ion Half/Full Cells and Sodium-Ion Batteries.

    Science.gov (United States)

    He, Yanyan; Li, Aihua; Dong, Caifu; Li, Chuanchuan; Xu, Liqiang

    2017-10-04

    The large volume variations of tin-based oxides hinder their extensive application in the field of lithium-ion batteries (LIBs). In this study, structure design, hybrid fabrication, and carbon-coating approaches have been simultaneously adopted to address these shortcomings. To this end, uniform mesoporous NiO/SnO 2 @rGO, Ni-Sn oxide@rGO, and SnO 2 @rGO nanosphere composites have been selectively fabricated. Among them, the obtained NiO/SnO 2 @rGO composite exhibited a high capacity of 800 mAh g -1 at 1000 mA g -1 after 400 cycles. The electrochemical mechanism of NiO/SnO 2 as an anode for LIBs has been preliminarily investigated by ex situ XRD pattern analysis. Furthermore, an NiO/SnO 2 @rGO-LiCoO 2 lithium-ion full cell showed a high capacity of 467.8 mAh g -1 at 500 mA g -1 after 100 cycles. Notably, the NiO/SnO 2 @rGO composite also showed good performance when investigated as an anode for sodium-ion batteries (SIBs). It is believed that the unique mesoporous nanospherical framework, synergistic effects between the various components, and uniform rGO wrapping of NiO/SnO 2 shorten the Li + ion diffusion pathways, maintain sufficient contact between the active material and the electrolyte, mitigate volume changes, and finally improve the electrical conductivity of the electrode. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Excellent performance of Pt-C/TiO2 for methanol oxidation: Contribution of mesopores and partially coated carbon

    Science.gov (United States)

    Wu, Xinbing; Zhuang, Wei; Lu, Linghong; Li, Licheng; Zhu, Jiahua; Mu, Liwen; Li, Wei; Zhu, Yudan; Lu, Xiaohua

    2017-12-01

    Partial deposition of carbon onto mesoporous TiO2 (C/TiO2) were prepared as supporting substrate for Pt catalyst development. Carbon deposition is achieved by in-situ carbonization of furfuryl alcohol. The hybrid catalysts were characterized by XRD, Raman, SEM and TEM and exhibited outstanding catalytic activity and stability in methanol oxidation reaction. The heterogeneous carbon coated on mesoporous TiO2 fibers provided excellent electrical conductivity and strong interfacial interaction between TiO2 support and Pt metal nanoparticles. Methanol oxidation reaction results showed that the activity of Pt-C/TiO2 is 3.0 and 1.5 times higher than that of Pt-TiO2 and Pt-C, respectively. In addition, the Pt-C/TiO2 exhibited a 6.7 times enhanced stability compared with Pt-C after 2000 cycles. The synergistic effect of C/TiO2 is responsible for the enhanced activity of Pt-C/TiO2, and its excellent durability could be ascribed to the strong interfacial interaction between Pt nanoparticles and C/TiO2 support.

  1. Quasi 2D Mesoporous Carbon Microbelts Derived from Fullerene Crystals as an Electrode Material for Electrochemical Supercapacitors.

    Science.gov (United States)

    Tang, Qin; Bairi, Partha; Shrestha, Rekha Goswami; Hill, Jonathan P; Ariga, Katsuhiko; Zeng, Haibo; Ji, Qingmin; Shrestha, Lok Kumar

    2017-12-27

    Fullerene C 60 microbelts were fabricated using the liquid-liquid interfacial precipitation method and converted into quasi 2D mesoporous carbon microbelts by heat treatment at elevated temperatures of 900 and 2000 °C. The carbon microbelts obtained by heat treatment of fullerene C 60 microbelts at 900 °C showed excellent electrochemical supercapacitive performance, exhibiting high specific capacitances ca. 360 F g -1 (at 5 mV s -1 ) and 290 F g -1 (at 1 A g -1 ) because of the enhanced surface area and the robust mesoporous framework structure. Additionally, the heat-treated carbon microbelt showed good rate performance, retaining 49% of capacitance at a high scan rate of 10 A g -1 . The carbon belts exhibit super cyclic stability. Capacity loss was not observed even after 10 000 charge/discharge cycles. These results demonstrate that the quasi 2D mesoporous carbon microbelts derived from a π-electron-rich carbon source, fullerene C 60 crystals, could be used as a new candidate material for electrochemical supercapacitor applications.

  2. Effect of hydrothermal treatment on catalytic activity of amorphous mesoporous Cr2O3–ZrO2 nanomaterials for ethanol oxidation

    International Nuclear Information System (INIS)

    Mahmoud, Hala R.

    2015-01-01

    Mesoporous 0.25Cr 2 O 3 –0.75ZrO 2 binary oxide catalysts (CZ-H) with high specific surface areas were successfully synthesized by hydrothermal treatment. The effect of synthesis conditions, such as hydrothermal temperature and time of CZ-H nanomaterials were investigated by X-ray diffraction (XRD), high-resolution transmission electron microscopy (HR-TEM), energy dispersive spectroscopic (EDS), UV–vis diffuse reflectance spectroscopy (DRS) and N 2 adsorption–desorption measurements (BET). The XRD analysis indicated the formation of amorphous materials of binary oxides. The results showed that hydrothermal temperature and time of CZ-H nanomaterials had great influence on the average particle diameter and surface area. Under the optimum synthesis conditions, the best CZ-H nanomaterial synthesized at 210 °C for 3 h (i.e., CZ-H213), presented spherical structure with smallest average particle diameter found to be 1.5 nm and possessed highest surface area of 526.6 m 2 /g. Optical studies by UV–vis spectroscopy for the different CZ-H nanomaterials exhibit slightly blue shift from 3.20 to 3.33 eV due to quantum confined exciton absorption. Moreover, hydrothermal synthesis leads to catalysts with higher surface area and with better acid–base properties than conventional co-precipitation method. Compared to the other nanomaterials, the CZ-H213 catalyst appears to be the best candidate for further application in acid–base catalysis and reusability. - Graphical abstract: Display Omitted - Highlights: • Mesoporous 25%Cr 2 O 3 –75%ZrO 2 catalysts (CZ-H) were prepared by hydrothermal method. • The hydrothermal temperature and time modified the properties of CZ-H nanomaterials. • The best CZ-H nanomaterial synthesized at 210 °C for 3 h (i.e., CZ-H213). • A CZ-H213 nanomaterial had the highest S BET and smallest average particle diameter. • A mesoporous CZ-H213 used as a reusable active catalyst in the ethanol conversion

  3. 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.

  4. Probing properties, stability, and performances of hierarchical meso-porous materials with nano-scale interfaces

    International Nuclear Information System (INIS)

    Baldinozzi, Gianguido; Gosset, Dominique; Simeone, David; Muller, Guillaume; Laberty-Robert, Christel; Sanchez, Clement

    2012-01-01

    Nano-crystals growth mechanism embedded into meso-porous thin films has been determined directly from grazing incidence X-ray diffraction data. We have shown, for the first time, that surface capillary forces control the growth mechanism of nano-crystals into these nano-architectures. Moreover, these data allow an estimation of the surface tension of the nano-crystals organized into a 3-D nano-architecture. The analysis of the variations in the strain field of these nano-crystals gives information on the evolution of the microstructure of these meso-porous films, that is, the contacts among nano-crystals. This work represents the first application of grazing incidence X-ray for understanding stability and performances of meso-porous thin films. This approach can be used to understand the structural stability of these nano-architectures at high temperature. (authors)

  5. Enhanced electrochemical performance of mesoporous NiCo{sub 2}O{sub 4} as an excellent supercapacitive alternative energy storage material

    Energy Technology Data Exchange (ETDEWEB)

    Bhojane, Prateek [Center for Materials Science and Engineering, Indian Institute of Technology Indore, Simrol Campus, Khandwa Road, Indore 452020 (India); Sen, Somaditya [Center for Materials Science and Engineering, Indian Institute of Technology Indore, Simrol Campus, Khandwa Road, Indore 452020 (India); Department of Physics, Indian Institute of Technology Indore, Simrol Campus, Khandwa Road, Indore 452020 (India); Shirage, Parasharam M., E-mail: paras.shirage@gmail.com [Center for Materials Science and Engineering, Indian Institute of Technology Indore, Simrol Campus, Khandwa Road, Indore 452020 (India); Department of Physics, Indian Institute of Technology Indore, Simrol Campus, Khandwa Road, Indore 452020 (India)

    2016-07-30

    Highlights: • A facile technique to grow mesopores NiCo{sub 2}O{sub 4} flakes. • High specific capacitance. • High capacitance retention at higher cycles. • A promising candidate for energy storage device. - Abstract: Here we report the supercapacitive properties of mesoporous nickel cobalt oxide (NiCo{sub 2}O{sub 4}) synthesized by fast, inexpensive and facile chemical bath method, by avoiding high pressure, high temperature and chemical complexity. Physico-chemical characterization techniques such as X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM), Raman Spectra, and nitrogen adsorption–desorption isotherm analysis is performed to characterize the electrode material. Brunauer-Emmett-Teller (BET) measurements reveal the surface area 52.86 m{sup 2} g{sup −1} and from Barrett-Joyner-Halenda (BJH), typical pores size ranges between 10 and 50 nm, also confirms the mesoporosity. The electrochemical properties are measured by cyclic voltammetry, electrochemical impedance spectroscopy and galvanostatic charging/discharging. The synthesized material exhibits remarkably enhanced electrochemical performance with specific capacitance of 1130 F g{sup −1} at 1 mV s{sup −1} sweep rate and 1125 F g{sup −1} at current density of 0.05 A g{sup −1}, highest without supporting base like carbon cloth, Ni-foam, Ti- foil used for direct growth (deposition) of electrode material. It is superior to those of its individual and hybrid components prepared by similar technique. Ragone plot shows high specific energy density (49.25 Wh kg{sup −1}) and corresponding specific power density (1851.31 W kg{sup −1}) even at high current density of 0.5 A g{sup −1}.

  6. Iron oxide nanoparticle layer templated by polydopamine spheres: a novel scaffold toward hollow-mesoporous magnetic nanoreactors.

    Science.gov (United States)

    Huang, Liang; Ao, Lijiao; Xie, Xiaobin; Gao, Guanhui; Foda, Mohamed F; Su, Wu

    2015-01-14

    Superparamagnetic iron oxide nanoparticle layers with high packing density and controlled thickness were in situ deposited on metal-affinity organic templates (polydopamine spheres), via one-pot thermal decomposition. The as synthesized hybrid structure served as a facile nano-scaffold toward hollow-mesoporous magnetic carriers, through surfactant-assisted silica encapsulation and its subsequent calcination. Confined but accessible gold nanoparticles were successfully incorporated into these carriers to form a recyclable catalyst, showing quick magnetic response and a large surface area (642.5 m(2) g(-1)). Current nano-reactors exhibit excellent catalytic performance and high stability in reduction of 4-nitrophenol, together with convenient magnetic separability and good reusability. The integration of compact iron oxide nanoparticle layers with programmable polydopamine templates paves the way to fabricate magnetic-response hollow structures, with high permeability and multi-functionality.

  7. Ibuprofen in mesopores of Mobil Crystalline Material 41 (MCM-41): a deeper understanding.

    Science.gov (United States)

    Skorupska, Ewa; Jeziorna, Agata; Paluch, Piotr; Potrzebowski, Marek J

    2014-05-05

    In this work, we compared two methods (incipient wetness and melting) for the encapsulation of ibuprofen in the pores of Mobil Crystalline Material 41 (MCM-41) through NMR (nuclear magnetic resonance) spectroscopy. (1)H NMR spectra were recorded under very fast MAS (sample spinning 60 kHz) conditions in both 1D and 2D mode (NOESY sequence). We also performed (13)C cross-polarization magic angle spinning (CP/MAS) experiments, (13)C single pulse experiments (SPE), and (1)H-(13)C HSQC HR/MAS (heteronuclear single quantum coherence high resolution) HR/MAS correlations. Evaluation of the encapsulation methods included an analysis of the filling factor of the drug into the pores. The stability of Ibu/MCM in an environment of ethanol or water vapor was tested. Our study showed that melting a mixture of Ibu and MCM is a much more efficient method of confining the drug in the pores compared to incipient wetness. The optimal experiments for the former method achieved a filling factor of approximately 60%. We concluded that the major limitation to the applicability of the incipient wetness method (filling factor ca. 20%) is the high affinity of solvent (typically ethanol) for MCM-41. We found that even ethanol vapor can remove Ibu from the pores. When a sample of Ibu/MCM was stored for a few hours in a closed vessel with ethanol vapor, Ibu was transported from the pores to the outer walls of MCM. We observed a similar phenomenon with water vapor, although this process is slower compared to the analogous procedure using ethanol. Our study clearly demonstrates that existing methods used to encapsulate drugs in mesoporous silica nanoparticles (MSNs) require reevaluation.

  8. Actinide Sequestration Using Self-Assembled Monolayers on Mesoporous Supports

    International Nuclear Information System (INIS)

    Fryxell, Glen E.; Lin, Yuehe; Fiskum, Sandra K.; Birnbaum, Jerome C.; Wu, Hong; Kemner, K. M.; Kelly, Shelley

    2005-01-01

    Surfactant templated synthesis of mesoporous ceramics provides a versatile foundation upon which to create high efficiency environmental sorbents. These nanoporous ceramic oxides condense a huge amount of surface area into a very small volume. The ceramic oxide interface is receptive to surface functionalization through molecular self-assembly. The marriage of mesoporous ceramics with self-assembled monolayer chemistry creates a powerful new class of environmental sorbent materials called self-assembled monolayers on mesoporous supports (SAMMS). These SAMMS materials are highly efficient sorbents, whose interfacial chemistry can be fine-tuned to selectively sequester a specific target species, such as heavy metals, tetrahedral oxometallate anions and radionuclides. Details addressing the design, synthesis and characterization of SAMMS materials specifically designed to sequester actinides, of central importance to the environmental clean-up necessary after 40 years of weapons grade plutonium production, as well as evaluation of their binding affinities and kinetics are presented

  9. Nanocomposite of graphene and metal oxide materials

    Science.gov (United States)

    Liu, Jun; Aksay, Ilhan A.; Choi, Daiwon; Wang, Donghai; Yang, Zhenguo

    2012-09-04

    Nanocomposite materials comprising a metal oxide bonded to at least one graphene material. The nanocomposite materials exhibit a specific capacity of at least twice that of the metal oxide material without the graphene at a charge/discharge rate greater than about 10C.

  10. Nanocomposite of graphene and metal oxide materials

    Science.gov (United States)

    Liu, Jun; Aksay, Ilhan A.; Choi, Daiwon; Wang, Donghai; Yang, Zhenguo

    2013-10-15

    Nanocomposite materials comprising a metal oxide bonded to at least one graphene material. The nanocomposite materials exhibit a specific capacity of at least twice that of the metal oxide material without the graphene at a charge/discharge rate greater than about 10 C.

  11. Micro–mesoporous iron oxides with record efficiency for the decomposition of hydrogen peroxide: morphology driven catalysis for the degradation of organic contaminants

    Science.gov (United States)

    A template-free solid-state synthesis of a morphologically controlled and highly organized iron(III)oxide micro–mesoporous Fenton catalyst has been engineered through a simple two-step synthetic procedure. The 3D nanoassembly of hematite nanoparticles (5–7 nm) organized into a ro...

  12. Manganese oxide-based multifunctionalized mesoporous silica nanoparticles for pH-responsive MRI, ultrasonography and circumvention of MDR in cancer cells.

    Science.gov (United States)

    Chen, Yu; Yin, Qi; Ji, Xiufeng; Zhang, Shengjian; Chen, Hangrong; Zheng, Yuanyi; Sun, Yang; Qu, Haiyun; Wang, Zheng; Li, Yaping; Wang, Xia; Zhang, Kun; Zhang, Linlin; Shi, Jianlin

    2012-10-01

    Nano-biotechnology has been introduced into cancer theranostics by engineering a new generation of highly versatile hybrid mesoporous composite nanocapsules (HMCNs) for manganese-based pH-responsive dynamic T(1)-weighted magnetic resonance imaging (MRI) to efficiently respond and detect the tumor acidic microenvironment, which was further integrated with ultrasonographic function based on the intrinsic unique hollow nanostructures of HMCNs for potentially in vitro and in vivo dual-modality cancer imaging. The manganese oxide-based multifunctionalization of hollow mesoporous silica nanoparticles was achieved by an in situ redox reaction using mesopores as the nanoreactors. Due to the dissolution nature of manganese oxide nanoparticles under weak acidic conditions, the relaxation rate r(1) of manganese-based mesoporous MRI-T(1) contrast agents (CAs) could reach 8.81 mM(-1)s(-1), which is a 11-fold magnitude increase compared to the neutral condition, and is almost two times higher than commercial Gd(III)-based complex agents. This is also the highest r(1) value ever reported for manganese oxide nanoparticles-based MRI-T(1) CAs. In addition, the hollow interiors and thin mesoporous silica shells endow HMCNs with the functions of CAs for efficient in vitro and in vivo ultrasonography under both harmonic- and B-modes. Importantly, the well-defined mesopores and large hollow interiors of HMCNs could encapsulate and deliver anticancer agents (doxorubicin) intracellularly to circumvent the multidrug resistance (MDR) of cancer cells and restore the anti-proliferative effect of drugs by nanoparticle-mediated endocytosis process, intracellular drug release and P-gp inhibition/ATP depletion in cancer cells. Copyright © 2012 Elsevier Ltd. All rights reserved.

  13. Nanocomposites based on graphene oxide and mesoporous silica nanoparticles: Preparation, characterization and nanobiointeractions with red blood cells and human plasma proteins

    Science.gov (United States)

    Fonseca, Leandro C.; de Araújo, Maciel M.; de Moraes, Ana Carolina M.; da Silva, Douglas S.; Ferreira, Ariane G.; Franqui, Lidiane S.; Martinez, Diego Stéfani T.; Alves, Oswaldo L.

    2018-04-01

    The current work refers to the development of a novel nanocomposite based on graphene oxide (GO) and mesoporous amino silica nanoparticles (H2N-MSNs) and its biological interaction with red blood cells (RBCs) and human blood plasma toward the investigation of nanobiointeractions. Silica nanoparticles and several graphene oxide-based materials are, separately, known for their high hemolytic potential and strong interaction with human plasma proteins. In this context, the GO-MSN interaction and its influence in minimizing the reported effects were investigated. The materials were synthesized by covalently attaching H2N-MSNs onto the surface of GO through an amidation reaction. GO-MSN nanocomposites were obtained by varying the mass of H2N-MSNs and were characterized by FTIR, NMR, XRD, TGA, zeta potential and TEM. The characterization results confirm that nanocomposites were obtained, suggest covalent bond attachment mostly by amine-epoxy reactions and evidence an unexpected reduction reaction of GO by H2N-MSNs, whose mechanism is proposed. Biological assays showed a decrease of hemolysis (RBC lysis) and a minimization of the interaction with human plasma proteins (protein corona formation). These are important findings toward achieving in vivo biocompatibility and understanding the nanobiointeractions. Finally, this work opens possibilities for new nanomedicine applications of GO-MSN nanocomposites, such as drug delivery system.

  14. Improved lithium cyclability and storage in mesoporous SnO2 electronically wired with very low concentrations (≤1 %) of reduced graphene oxide.

    Science.gov (United States)

    Shiva, Konda; Rajendra, H B; Subrahmanyam, K S; Bhattacharyya, Aninda J; Rao, C N R

    2012-04-10

    On the wire: Mesoporous tin dioxide (SnO(2)) wired with very low amounts (≤1 %) of reduced graphene oxide (rGO) exhibits a remarkable improvement in lithium-ion battery performance over bare mesoporous or solid nanoparticles of SnO(2). Reversible lithium intercalation into SnO(2)/SnO over several cycles was demonstrated in addition to conventional reversible lithium storage by an alloying reaction. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Low temperature oxidative desulfurization with hierarchically mesoporous titaniumsilicate Ti-SBA-2 single crystals.

    Science.gov (United States)

    Shi, Chengxiang; Wang, Wenxuan; Liu, Ni; Xu, Xueyan; Wang, Danhong; Zhang, Minghui; Sun, Pingchuan; Chen, Tiehong

    2015-07-21

    Hierarchically porous Ti-SBA-2 with high framework Ti content (up to 5 wt%) was firstly synthesized by employing organic mesomorphous complexes of a cationic surfactant (CTAB) and an anionic polyelectrolyte (PAA) as templates. The material exhibited excellent performance in oxidative desulfurization of diesel fuel at low temperature (40 °C or 25 °C) due to the unique hierarchically porous structure and high framework Ti content.

  16. 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

  17. 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...

  18. 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

  19. 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.

  20. Synthesis of Nano-Zinc Oxide Loaded on Mesoporous Silica by Coordination Effect and Its Photocatalytic Degradation Property of Methyl Orange.

    Science.gov (United States)

    Shen, Zhichuan; Zhou, Hongjun; Chen, Huayao; Xu, Hua; Feng, Chunhua; Zhou, Xinhua

    2018-05-09

    Salicylaldimine-modified mesoporous silica (Sal-MCM-3 and Sal-MCM-9) was prepared through a co-condensation method with different amounts of added salicylaldimine. With the coordination from the salicylaldimine, zinc ions were impregnated on Sal-MCM-3 and Sal-MCM-9. Then, Zn-Sal-MCM-3 and Zn-Sal-MCM-9 were calcined to obtain nano-zinc oxide loaded on mesoporous silica (ZnO-MCM-3 and ZnO-MCM-9). The material structures were systematically studied by Fourier transform infrared spectroscopy (FTIR), N₂ adsorption/desorption measurements, X-ray powder diffraction (XRD), zeta potential, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), ultraviolet diffused reflectance spectrum (UV-vis DRS), and thermogravimetry (TGA). Methyl orange (MO) was used to investigate the photocatalysis behavior of ZnO-MCM-3 and ZnO-MCM-9. The results confirmed that nano ZnO was loaded in the channels as well as the outside surface of mesoporous silica (MCM-41). The modification of salicylaldimine helped MCM-41 to load more nano ZnO on MCM-41. When the modification amount of salicylaldimine was one-ninth and one-third of the mass of the silicon source, respectively, the load of nano ZnO on ZnO-MCM-9 and ZnO-MCM-3 had atomic concentrations of 1.27 and 2.03, respectively. ZnO loaded on ZnO-MCM-9 had a wurtzite structure, while ZnO loaded on ZnO-MCM-3 was not in the same crystalline group. The blocking effect caused by nano ZnO in the channels reduced the orderliness of MCM-41. The photodegradation of MO can be divided in two processes, which are mainly controlled by the surface areas of ZnO-MCM and the loading amount of nano ZnO, respectively. The pseudo-first-order model was more suitable for the photodegradation process.

  1. 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.

  2. Metallorganic routes to nanoscale iron and titanium oxide particles encapsulated in mesoporous alumina: formation, physical properties, and chemical reactivity.

    Science.gov (United States)

    Schneider, J J; Czap, N; Hagen, J; Engstler, J; Ensling, J; Gütlich, P; Reinoehl, U; Bertagnolli, H; Luis, F; de Jongh, L J; Wark, M; Grubert, G; Hornyak, G L; Zanoni, R

    2000-12-01

    Iron and titanium oxide nanoparticles have been synthesized in parallel mesopores of alumina by a novel organometallic "chimie douce" approach that uses bis(toluene)iron(0) (1) and bis(toluene)titanium(0) (2) as precursors. These complexes are molecular sources of iron and titanium in a zerovalent atomic state. In the case of 1, core shell iron/iron oxide particles with a strong magnetic coupling between both components, as revealed by magnetic measurements, are formed. Mössbauer data reveal superparamagnetic particle behavior with a distinct particle size distribution that confirms the magnetic measurements. The dependence of the Mössbauer spectra on temperature and particle size is explained by the influence of superparamagnetic relaxation effects. The coexistence of a paramagnetic doublet and a magnetically split component in the spectra is further explained by a distribution in particle size. From Mössbauer parameters the oxide phase can be identified as low-crystallinity ferrihydrite oxide. In agreement with quantum size effects observed in UV-visible studies, TEM measurements determine the size of the particles in the range 5-8 nm. The particles are mainly arranged alongside the pore walls of the alumina template. TiO2 nanoparticles are formed by depositing 2 in mesoporous alumina template. This produces metallic Ti, which is subsequently oxidized to TiO2 (anatase) within the alumina pores. UV-visible studies show a strong quantum confinement effect for these particles. From UV-visible investigations the particle size is determined to be around 2 nm. XPS analysis of the iron- and titania- embedded nanoparticles reveal the presence of Fe2O3 and TiO2 according to experimental binding energies and the experimental line shapes. Ti4+ and Fe3+ are the only oxidation states of the particles which can be determined by this technique. Hydrogen reduction of the iron/iron-oxide nanoparticles at 500 degrees C under flowing H2/N2 produces a catalyst, which is active

  3. Mesoporous titanium phosphate molecular sieves with ion-exchange capacity.

    Science.gov (United States)

    Bhaumik, A; Inagaki, S

    2001-01-31

    Novel open framework molecular sieves, titanium(IV) phosphates named, i.e., TCM-7 and -8 (Toyota Composite Materials, numbers 7 and 8), with new mesoporous cationic framework topologies obtained by using both cationic and anionic surfactants are reported. The (31)P MAS NMR, UV-visible absorption, and XANES data suggest the tetrahedral state of P and Ti, and stabilization of the tetrahedral state of Ti in TCM-7/8 is due to the incorporation of phosphorus (at Ti/P = 1:1) vis-à-vis the most stable octahedral state of Ti in the pure mesoporous TiO(2). Mesoporous TCM-7 and -8 show anion exchange capacity due to the framework phosphonium cation and cation exchange capacity due to defective P-OH groups. The high catalytic activity in the liquid-phase partial oxidation of cyclohexene with a dilute H(2)O(2) oxidant supports the tetrahedral coordination of Ti in these materials.

  4. Mesoporous iron–manganese oxides for sulphur mustard and soman degradation

    Energy Technology Data Exchange (ETDEWEB)

    Štengl, Václav, E-mail: stengl@iic.cas.cz [Department of Solid State Chemistry, Institute of Inorganic Chemistry AS CR, v.v.i., 250 68 Řež (Czech Republic); J.E. Purkyně University in Ústí nad Labem, Faculty of Environment, 400 96 Ústí nad Labem (Czech Republic); Grygar, Tomáš Matys [Department of Solid State Chemistry, Institute of Inorganic Chemistry AS CR, v.v.i., 250 68 Řež (Czech Republic); J.E. Purkyně University in Ústí nad Labem, Faculty of Environment, 400 96 Ústí nad Labem (Czech Republic); Bludská, Jana [Department of Solid State Chemistry, Institute of Inorganic Chemistry AS CR, v.v.i., 250 68 Řež (Czech Republic); Opluštil, František; Němec, Tomáš [Military Technical Institute of Protection Brno, Veslařská 230, 628 00 Brno (Czech Republic)

    2012-12-15

    Graphical abstract: Display Omitted Highlights: ► New nanodispersive materials based on Fe and Mn oxides for degradations of warfare agents. ► The best activities for the degradation of sulphur mustard (97.9% in 64 min) and soman (97.9% in 64 min). ► One pot synthesis with friendly transformed to industrial conditions. -- Abstract: Substituted iron(III)–manganese(III, IV) oxides, ammonio-jarosite and birnessite, were prepared by a homogeneous hydrolysis of potassium permanganate and iron(III) sulphate with 2-chloroacetamide and urea, respectively. Synthesised oxides were characterised using Brunauer–Emmett–Teller (BET) surface area and Barrett–Joiner–Halenda porosity (BJH), X-ray diffraction (XRD), infrared spectroscopy (IR), Raman spectroscopy and scanning electron microscopy (SEM). The oxides were taken for an experimental evaluation of their reactivity against sulphur mustard (HD) and soman (GD). When ammonio-jarosite formation is suppressed by adding urea to the reaction mixture, the reaction products are mixtures of goethite, schwertmannite and ferrihydrite, and their degradation activity against soman considerably increases. The best activities for the degradation of sulphur mustard (97.9% in 64 min) and soman (97.9% in 64 min) were observed for FeMn{sub 7}5 with 32.6 wt.% Fe (36.8 wt.% Mn) and FeMn{sub 3}7U with 60.8 wt.% Fe (10.1 wt.% Mn) samples, respectively.

  5. Mesoporous iron–manganese oxides for sulphur mustard and soman degradation

    International Nuclear Information System (INIS)

    Štengl, Václav; Grygar, Tomáš Matys; Bludská, Jana; Opluštil, František; Němec, Tomáš

    2012-01-01

    Graphical abstract: Display Omitted Highlights: ► New nanodispersive materials based on Fe and Mn oxides for degradations of warfare agents. ► The best activities for the degradation of sulphur mustard (97.9% in 64 min) and soman (97.9% in 64 min). ► One pot synthesis with friendly transformed to industrial conditions. -- Abstract: Substituted iron(III)–manganese(III, IV) oxides, ammonio-jarosite and birnessite, were prepared by a homogeneous hydrolysis of potassium permanganate and iron(III) sulphate with 2-chloroacetamide and urea, respectively. Synthesised oxides were characterised using Brunauer–Emmett–Teller (BET) surface area and Barrett–Joiner–Halenda porosity (BJH), X-ray diffraction (XRD), infrared spectroscopy (IR), Raman spectroscopy and scanning electron microscopy (SEM). The oxides were taken for an experimental evaluation of their reactivity against sulphur mustard (HD) and soman (GD). When ammonio-jarosite formation is suppressed by adding urea to the reaction mixture, the reaction products are mixtures of goethite, schwertmannite and ferrihydrite, and their degradation activity against soman considerably increases. The best activities for the degradation of sulphur mustard (97.9% in 64 min) and soman (97.9% in 64 min) were observed for FeMn 7 5 with 32.6 wt.% Fe (36.8 wt.% Mn) and FeMn 3 7U with 60.8 wt.% Fe (10.1 wt.% Mn) samples, respectively.

  6. Template-assisted electrostatic spray deposition as a new route to mesoporous, macroporous, and hierarchically porous oxide films.

    Science.gov (United States)

    Sokolov, S; Paul, B; Ortel, E; Fischer, A; Kraehnert, R

    2011-03-01

    A novel film coating technique, template-assisted electrostatic spray deposition (TAESD), was developed for the synthesis of porous metal oxide films and tested on TiO(2). Organic templates are codeposited with the titania precursor by electrostatic spray deposition and then removed during calcination. Resultant films are highly porous with pores casted by uniformly sized templates, which introduced a new level of control over the pore morphology for the ESD method. Employing the amphiphilic block copolymer Pluronic P123, PMMA latex spheres, or a combination of the two, mesoporous, macroporous, and hierarchically porous TiO(2) films are obtained. Decoupled from other coating parameters, film thickness can be controlled by deposition time or depositing multiple layers while maintaining the coating's structure and integrity.

  7. Hollow mesoporous CuCo2O4 microspheres derived from metal organic framework: A novel functional materials for simultaneous H2O2 biosensing and glucose biofuel cell.

    Science.gov (United States)

    Cui, Shiqiang; Gu, Shuqing; Ding, Yaping; Zhang, Jiangjiang; Zhang, Zhen; Hu, Zongqian

    2018-02-01

    Hollow mesoporous CuCo 2 O 4 (meso-CuCo 2 O 4 ) microspheres were successfully synthesized by decomposing metal-organic frameworks (MOFs) as the template. The as-prepared CuCo 2 O 4 microspheres were first simultaneously used for H 2 O 2 biosensing and glucose biofuel cell (GFC) as the enzyme mimic. The resulting of meso-CuCo 2 O 4 displayed not only excellent catalytic performances to H 2 O 2 including a super-fast response time (within 2s), a super-high sensitivity (654.23 μA mM -1 cm -2 ) and a super-low detection limit (3nM at S/N = 3) on the sensor, but also great values in GFC as anode material with an open circuit voltage of 0.85V, a maximum power density of 0.33 mWcm -2 and a limiting current density of 1.27 mAcm -2 , respectively. The preeminent catalytic abilities to H 2 O 2 and glucose may be attributed to the surpassing intrinsic catalytic activity of CuCo 2 O 4 and large specific area of mesoporous structure. These significant findings deriving from this work not only provided a novel exploration for the fabrication of hollow spherical mesoporous bimetallic oxides, but also promoted the development of the supersensitive detection of H 2 O 2 and non-enzymatic biofuel cell. Copyright © 2017. Published by Elsevier B.V.

  8. Micro-mesoporous carbon spheres derived from carrageenan as electrode material for supercapacitors

    Science.gov (United States)

    Fan, Yang; Yang, Xin; Zhu, Bing; Liu, Pei-Fang; Lu, Hai-Ting

    2014-12-01

    The polysaccharide carrageenan is used as a natural precursor to prepare micro-mesoporous carbon spheres. The carbon spheres were synthesized by hydrothermal carbonization of carrageenan, and subsequent chemical activation by KOH at different temperatures. The obtained micro-mesoporous carbon spheres have high surface area (up to 2502 m2 g-1) and large pore volume (up to 1.43 cm3 g-1). Moreover, the micro- and mesoporosity can be finely tuned be modifying the activation temperatures in the range of 700-900 °C. The carbon spheres activated at 900 °C present high specific capacitance of 230 F g-1 at a current density of 1 A g-1 and good ion transport kinetics. The good capacitive performance can be ascribed to the high specific surface area, well-controlled micro- and mesoporosity and narrow pore size distribution.

  9. 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.

  10. Facile synthesis of single-crystal mesoporous CoNiO2 nanosheets assembled flowers as anode materials for lithium-ion batteries

    International Nuclear Information System (INIS)

    Liu, Yanguo; Zhao, Yanyan; Yu, Yanlong; Ahmad, Mashkoor; Sun, Hongyu

    2014-01-01

    Highlights: • Mesoporous CoNiO 2 microflowers have been synthesized. • Li-ion batteries performance of CoNiO 2 has been investigated. • CoNiO 2 structure delivers high capacity, good cycling stability and high rate capability. • The electrochemical performance is attributed to the mesoporous nature and the 3D structure. • CoNiO 2 can be considered to be an attractive candidate as an electrode material for LIBs. - Abstract: Mesoporous CoNiO 2 microflowers assembled with single-crystal nanosheets were successfully synthesized by a hydrothermal method and subsequent annealing process and their lithium storage capacity were investigated. The structural and compositional analysis of the mesoporous CoNiO 2 microflowers has been studied by X-ray diffraction, field emission scanning electron microscopy and high-resolution transmission electron microscopy. The Bruauer–Emmett–Teller specific surface area of CoNiO 2 microflowers has been calculated by the nitrogen isotherm curve and pore size distribution has been determined by the Barret–Joyner–Halenda method. It has been found that the as-prepared CoNiO 2 electrodes delivered satisfied capacity, good cycling stability and rate capability. The improved electrochemical performance is attributed to the mesoporous nature and the 3D assembled structure. Therefore, such a structure can be considered to be an attractive candidate as an electrode material for lithium-ion batteries

  11. 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.

  12. Oxidized template-synthesized mesoporous carbon with pH-dependent adsorption activity: A promising adsorbent for removal of hydrophilic ionic liquid

    Science.gov (United States)

    Zhang, Ling; Cao, Wugang; Alvarez, Pedro J. J.; Qu, Xiaolei; Fu, Heyun; Zheng, Shourong; Xu, Zhaoyi; Zhu, Dongqiang

    2018-05-01

    Aiming to remove ionic liquid pollutants from water, an ordered mesoporous carbon CMK-3 (OMC) was prepared and modified by oxidation with nitric acid. A commercial microporous activated carbon adsorbent, Filtrasorb-300 (AC), was used as benchmark. Boehm titration showed that oxidized OMC had a substantially higher oxygen content than oxidized AC. Adsorption of the hydrophilic imidazolium-based ionic liquid 1-Butyl-3-methylimidazolium chloride ([Bmim]Cl) on OMC and AC was well-described by the Freundlich isotherm model. Surface oxidation markedly enhanced [Bmim]Cl adsorption by both OMC and AC. Nevertheless, [Bmim]Cl adsorption was much higher on oxidized OMC than on oxidized AC. Increasing pH had negligible influence on [Bmim]Cl adsorption on pristine OMC, but enhanced adsorption on oxidized OMC. Regeneration tests showed stable performance of oxidized OMC over five adsorption-desorption cycles. Thus, oxidized OMC can be a highly effective adsorbent for the removal of hydrophilic ionic liquids from water.

  13. Layer-by-Layer Motif Architectures: Programmed Electrochemical Syntheses of Multilayer Mesoporous Metallic Films with Uniformly Sized Pores.

    Science.gov (United States)

    Jiang, Bo; Li, Cuiling; Qian, Huayu; Hossain, Md Shahriar A; Malgras, Victor; Yamauchi, Yusuke

    2017-06-26

    Although multilayer films have been extensively reported, most compositions have been limited to non-catalytically active materials (e.g. polymers, proteins, lipids, or nucleic acids). Herein, we report the preparation of binder-free multilayer metallic mesoporous films with sufficient accessibility for high electrocatalytic activity by using a programmed electrochemical strategy. By precisely tuning the deposition potential and duration, multilayer mesoporous architectures consisting of alternating mesoporous Pd layers and mesoporous PdPt layers with controlled layer thicknesses can be synthesized within a single electrolyte, containing polymeric micelles as soft templates. This novel architecture, combining the advantages of bimetallic alloys, multilayer architectures, and mesoporous structures, exhibits high electrocatalytic activity for both the methanol oxidation reaction (MOR) and the ethanol oxidation reaction (EOR). © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Nanocasted synthesis of magnetic mesoporous iron cerium bimetal oxides (MMIC) as an efficient heterogeneous Fenton-like catalyst for oxidation of arsenite.

    Science.gov (United States)

    Wen, Zhipan; Zhang, Yalei; Dai, Chaomeng; Sun, Zhen

    2015-04-28

    Magnetic mesoporous iron cerium bimetal oxides (MMIC) with large surface area and pore volume was synthesized via the hard template approach. This obtained MMIC was easily separated from aqueous solution with an external magnetic field and was proposed as a heterogeneous Fenton-like catalyst for oxidation of As(III). The MMIC presented excellent catalytic activity for the oxidation of As(III), achieving almost complete oxidation of 1000ppb As(III) after 60min and complete removal of arsenic species after 180min with reaction conditions of 0.4g/L catalyst, pH of 3.0 and 0.4mM H2O2. Kinetics analysis showed that arsenic removal followed the pseudo-first order, and the pseudo-first-order rate constants increased from 0.0014min(-1) to 0.0548min(-1) as the H2O2 concentration increased from 0.04mM to 0.4mM. On the basis of the effects of XPS analysis and reactive oxidizing species, As(III) in aqueous solution was mainly oxidized by OH radicals, including the surface-bound OHads generated on the MMIC surface which were involved in Fe(2+) and Ce(3+), and free OHfree generation by soluble iron ions which were released from the MMIC into the bulk solution, and the generated As(V) was finally removed by MMIC through adsorption. Copyright © 2015 Elsevier B.V. All rights reserved.

  15. Efficient dye-sensitized solar cells from mesoporous zinc oxide nanostructures sensitized by N719 dye

    Science.gov (United States)

    Kumara, G. R. A.; Deshapriya, U.; Ranasinghe, C. S. K.; Jayaweera, E. N.; Rajapakse, R. M. G.

    2018-03-01

    Dye-sensitized solar cells (DSCs) have attracted a great deal of attention due to their low-cost and high power conversion efficiencies. They usually utilize an interconnected nanoparticle layer of TiO2 as the electron transport medium. From the fundamental point of view, faster mobility of electrons in ZnO is expected to contribute to better performance in DSCs than TiO2, though the actual practical situation is quite the opposite. In this research, we addressed this problem by first applying a dense layer of ZnO on FTO followed by a mesoporous layer of interconnected ZnO nanoparticle layer, both were prepared by spray pyrolysis technique. The best cell shows a power conversion efficiency of 5.2% when the mesoporous layer thickness is 14 μm and the concentration of the N719 dye in dye coating solution is 0.3 mM, while a cell without a dense layer shows 4.2% under identical conditions. The surface concentration of dye adsorbed in the cell with a dense layer and that without a dense layer are 5.00 × 10‑7 and 3.34 × 10‑7 mol/cm2, respectively. The cell with the dense layer has an electron lifetime of 54.81 ms whereas that without the dense layer is 11.08 ms. As such, the presence of the dense layer improves DSC characteristics of ZnO-based DSCs.

  16. Degradability and Clearance of Silicon, Organosilica, Silsesquioxane, Silica Mixed Oxide, and Mesoporous Silica Nanoparticles

    KAUST Repository

    Croissant, Jonas G.

    2017-01-13

    The biorelated degradability and clearance of siliceous nanomaterials have been questioned worldwide, since they are crucial prerequisites for the successful translation in clinics. Typically, the degradability and biocompatibility of mesoporous silica nanoparticles (MSNs) have been an ongoing discussion in research circles. The reason for such a concern is that approved pharmaceutical products must not accumulate in the human body, to prevent severe and unpredictable side-effects. Here, the biorelated degradability and clearance of silicon and silica nanoparticles (NPs) are comprehensively summarized. The influence of the size, morphology, surface area, pore size, and surface functional groups, to name a few, on the degradability of silicon and silica NPs is described. The noncovalent organic doping of silica and the covalent incorporation of either hydrolytically stable or redox- and enzymatically cleavable silsesquioxanes is then described for organosilica, bridged silsesquioxane (BS), and periodic mesoporous organosilica (PMO) NPs. Inorganically doped silica particles such as calcium-, iron-, manganese-, and zirconium-doped NPs, also have radically different hydrolytic stabilities. To conclude, the degradability and clearance timelines of various siliceous nanomaterials are compared and it is highlighted that researchers can select a specific nanomaterial in this large family according to the targeted applications and the required clearance kinetics.

  17. Electrochemical behavior of two and one electron redox systems adsorbed on to micro- and mesoporous silicate materials: Influence of the channels and the cationic environment of the host materials

    International Nuclear Information System (INIS)

    Senthil Kumar, K.; Natarajan, P.

    2009-01-01

    Electrochemical behavior of two electron redox system, phenosafranine (PS + ) adsorbed on to micro- and mesoporous materials is investigated by cyclic voltammetry and differential pulse voltammetry using modified micro- and mesoporous host electrodes. Two redox peaks were observed when phenosafranine is adsorbed on the surface of microporous materials zeolite-Y and ZSM-5. However, only a single redox peak was observed in the modified electrode with phenosafranine encapsulated into the mesoporous material MCM-41 and when adsorbed on the external surface of silica. The observed redox peaks for the modified electrodes with zeolite-Y and ZSM-5 host are suggested to be primarily due to consecutive two electron processes. The peak separation ΔE and peak potential of phenosafranine adsorbed on zeolite-Y and ZSM-5 were found to be influenced by the pH of the electrolyte solution. The variation of the peak current in the cyclic voltammogram and differential pulse voltammetry with scan rate shows that electrodic processes are controlled by the nature of the surface of the host material. The heterogeneous electron transfer rate constants for phenosafranine adsorbed on to micro- and mesoporous materials were calculated using the Laviron model. Higher rate constant observed for the dye encapsulated into the MCM-41 indicates that the one-dimensional channel of the mesoporous material provides a more facile micro-environment for phenosafranine for the electron transfer reaction as compared to the microporous silicate materials. The stability of the modified electrode surface was investigated by multisweep cyclic voltammetry.

  18. 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.

  19. 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.

  20. Introduction to the first International Workshop on the Application of Microporous and Mesoporous Materials as Catalytic Hosts for Fe, Cu an Co

    NARCIS (Netherlands)

    Donk, van S.; Weckhuysen, B.M.; Kapteijn, F.; Kooyman, P.J.; Hensen, E.J.M.

    2005-01-01

    This Special Issue of Catalysis Today includes a selection of research presented at the first International Workshop on the ‘Application of Microporous and Mesoporous Materials as Catalytic Hosts for Fe, Cu and Co’, held in Scheveningen, The Netherlands, 1–4 March 2005. This 3-day event welcomed

  1. Synthesis of an Ionic Liquid and Its Application as Template for the Preparation of Mesoporous Material MCM-41: A Comprehensive Experiment for Undergraduate Students

    Science.gov (United States)

    Hu, Jun; Yin, Jinxiang; Lin, Tianshu; Li, Guangtao

    2012-01-01

    A new solvent-free microwave experiment to synthesize the ionic liquid 1-hexadecyl-3-methylimidazolium bromide (HDMIm-Br) in high yield is presented. The structure is confirmed by IR and [superscript 1]H NMR spectra. HDMIm-Br is then used to prepare an organic-inorganic mesoporous material MCM-41. The microscopic arrangements of mesoporous…

  2. NMR studies of organic liquids confined in mesoporous materials: (1) Pore size distribution and (2) Phase behaviour and dynamic studies in restricted geometry

    International Nuclear Information System (INIS)

    Foerland, Kjersti

    2005-01-01

    In the thesis NMR spectroscopy is used for studying liquids confined in various porous materials. In the first part, pore size distributions of mesoporous silicas and controlled pore glasses were determined by measuring the 1H NMR signal from the non-frozen fraction of the confined liquid as a function of temperature, using benzene, acetonitrile and HMDS as probe molecules. In the second part, the molecular dynamics of acetonitrile, hexamethyldisilane, cyclohexane and cyclopentane confined in mesoporous materials were studied as a function of temperature. 6 papers are included with titles: 1) Pore-size determination of mesoporous materials by 1H NMR spectroscopy. 2) Pore-size distribution in mesoporous materials as studied by 1H NMR. 3) Dynamic 1H and 2H NMR investigations of acetonitrile confined in porous silica. 4) NMR investigations of hexamethyldisilane confined in controlled pore glasses: Pore size distribution and molecular dynamics studies. 5) 1H and 2H NMR studies of cyclohexane nano crystals in controlled pore glasses. 6) 1H NMR relaxation and diffusion studies of cyclohexane and cyclopentane confined in MCM-41

  3. NMR studies of organic liquids confined in mesoporous materials: (1) Pore size distribution and (2) Phase behaviour and dynamic studies in restricted geometry

    Energy Technology Data Exchange (ETDEWEB)

    Foerland, Kjersti

    2005-07-01

    In the thesis NMR spectroscopy is used for studying liquids confined in various porous materials. In the first part, pore size distributions of mesoporous silicas and controlled pore glasses were determined by measuring the 1H NMR signal from the non-frozen fraction of the confined liquid as a function of temperature, using benzene, acetonitrile and HMDS as probe molecules. In the second part, the molecular dynamics of acetonitrile, hexamethyldisilane, cyclohexane and cyclopentane confined in mesoporous materials were studied as a function of temperature. 6 papers are included with titles: 1) Pore-size determination of mesoporous materials by 1H NMR spectroscopy. 2) Pore-size distribution in mesoporous materials as studied by 1H NMR. 3) Dynamic 1H and 2H NMR investigations of acetonitrile confined in porous silica. 4) NMR investigations of hexamethyldisilane confined in controlled pore glasses: Pore size distribution and molecular dynamics studies. 5) 1H and 2H NMR studies of cyclohexane nano crystals in controlled pore glasses. 6) 1H NMR relaxation and diffusion studies of cyclohexane and cyclopentane confined in MCM-41.

  4. Bimetallic oxamato complexes synthesized into mesoporous matrix as precursor to tunable nanosized oxide

    Energy Technology Data Exchange (ETDEWEB)

    Kalinke, Lucas H.G. [Instituto de Química, Universidade Federal de Goiás—UFG, Goiânia, GO 74001-970 (Brazil); Instituto Federal de Goiás—IFG, Anápolis, GO (Brazil); Stumpf, Humberto O. [Departamento de Química, Instituto de Ciências Exatas, Universidade Federal de Minas Gerais—UFMG, Belo Horizonte, MG (Brazil); Mazali, Italo O. [Instituto de Química, Universidade Estadual de Campinas—UNICAMP, Campinas, SP (Brazil); Cangussu, Danielle, E-mail: danielle_cangussu@ufg.br [Instituto de Química, Universidade Federal de Goiás—UFG, Goiânia, GO 74001-970 (Brazil)

    2015-10-15

    Highlights: • The bimetallic oxamato complexes as single-source precursor. • We prepared into a porous silica glass tunable nanosized oxide powders. • X-ray diffraction shows the formation of CeO{sub 2}/CuO and spinel cobaltite. • The different number of IDC allows control of the nanoparticle size. - Abstract: The bimetallic complexes were employed to prepare into a porous silica glass tunable nanosized oxide powders through the single source precursor (SSP) method. These materials were prepared by first anchoring of [Cu(opba)]{sup 2−} [opba = ortho-phenylenebis(oxamato)], second by reaction in situ with second metal [Co(II) or Ce(III)] and followed by a thermal treatment. The different number of impregnation–decomposition cycles (IDC) allows control of the nanoparticle size. X-ray diffraction shows the formation of mixture CeO{sub 2}–CuO and spinel copper cobaltite. Raman spectroscopy confirmed the formation of such phases. Transmission electron microscopy images revealed that spinel cobaltite particles (8 IDC) present a mean size of about 9 nm, whereas for the CeO{sub 2}–CuO phase the particle diameters are 4 nm (2 IDC) and 8 nm (6 IDC). For CeO{sub 2}–CuO the diffuse reflectance spectroscopy indicates a consistent red shift in band gap from 3.41 to 2.87 eV with increasing of particle size due to quantum confinement effect.

  5. Direct synthesis of bimetallic PtCo mesoporous nanospheres as efficient bifunctional electrocatalysts for both oxygen reduction reaction and methanol oxidation reaction

    Science.gov (United States)

    Wang, Hongjing; Yu, Hongjie; Li, Yinghao; Yin, Shuli; Xue, Hairong; Li, Xiaonian; Xu, You; Wang, Liang

    2018-04-01

    The engineering of electrocatalysts with high performance for cathodic and/or anodic catalytic reactions is of great urgency for the development of direct methanol fuel cells. Pt-based bimetallic alloys have recently received considerable attention in the field of fuel cells because of their superior catalytic performance towards both fuel molecule electro-oxidation and oxygen reduction. In this work, bimetallic PtCo mesoporous nanospheres (PtCo MNs) with uniform size and morphology have been prepared by a one-step method with a high yield. The as-made PtCo MNs show superior catalytic activities for both oxygen reduction reaction and methanol oxidation reaction relative to Pt MNs and commercial Pt/C catalyst, attributed to their mesoporous structure and bimetallic composition.

  6. Tuning the acidity of niobia: Characterization and catalytic activity of Nb{sub 2}O{sub 5}–MeO{sub 2} (Me = Ti, Zr, Ce) mesoporous mixed oxides

    Energy Technology Data Exchange (ETDEWEB)

    Stošić, Dušan; Bennici, Simona [Université Lyon 1, CNRS, UMR 5256, IRCELYON, Institut de recherches sur la catalyse et l' environnement de Lyon, 2 avenue Albert Einstein, F-69626 Villeurbanne (France); Pavlović, Vladimir; Rakić, Vesna [Faculty of Agriculture, Department of Chemistry, University of Belgrade, Nemanjina 6, 11080 Zemun (Serbia); Auroux, Aline, E-mail: aline.auroux@ircelyon.univ-lyon1.fr [Université Lyon 1, CNRS, UMR 5256, IRCELYON, Institut de recherches sur la catalyse et l' environnement de Lyon, 2 avenue Albert Einstein, F-69626 Villeurbanne (France)

    2014-08-01

    Mesoporous Nb{sub 2}O{sub 5}–MeO{sub 2} (Me = Ti, Zr, Ce) mixed oxides were successfully prepared using evaporation-induced self-assembly (EISA) method. The structural and textural properties of these materials have been fully characterized using appropriate techniques (low-temperature adsorption–desorption of nitrogen, thermogravimetric analysis, X-ray diffraction analysis (XRD) transmission electron microscopy (TEM), scanning electron microscopy (SEM) and Raman spectroscopy). Acid–base properties were estimated by adsorption microcalorimetry of NH{sub 3} and SO{sub 2} molecules in order to determine the population, strength and strength distribution of acidic or basic sites. Formation of mesoporous structure was confirmed by the results of XRD, TEM and BET techniques. Results of adsorption microcalorimetry technique showed that the type of transition metal oxide added to niobia has a decisive role for acidic-basic character of investigated mixed oxides. Among the investigated mixed oxide formulations only Nb{sub 2}O{sub 5}–CeO{sub 2} was amphoteric, while the other samples showed prominent acidic character. All the investigated materials are catalytically active in fructose dehydration; conversion of fructose and selectivity to 5-hydroxymethylfurfural (5-HMF) and levulinic acid (LA) are proved to be dependant on the number of acidic sites on the surface of catalysts. Furthermore, presence of the basic sites on the surface of the catalyst decreases the activity in the fructose dehydration reaction, as in the case of Nb{sub 2}O{sub 5}–CeO{sub 2} sample. - Highlights: • Mesoporous Nb{sub 2}O{sub 5}–MeO{sub 2} mixed oxides were successfully prepared by EISA method. • Acidic–basic properties depend on the nature of the oxide that was mixed with niobia. • Catalytic activity was tested in fructose dehydration in aqueous phase. • Selectivity and conversion in reaction are correlated to the number of acid sites.

  7. Meso-porous α-Fe2O3 thin films synthesized via the sol-gel process for light-driven water oxidation

    International Nuclear Information System (INIS)

    Hamd, Wael; Laberty-Robert, Christel; Sanchez, Clement; Cobo, Saioa; Fize, Jennifer; Artero, Vincent; Baldinozzi, Gianguido; Schwartz, Wilfrid; Reymermier, Maryse; Pereira, Alexandre; Fontecave, Marc

    2012-01-01

    This work reports a facile and cost-effective method for synthesizing photoactive α-Fe 2 O 3 films as well as their performances when used as photoanodes for water oxidation. Transparent α-Fe 2 O 3 meso-porous films were fabricated by template-directed sol-gel chemistry coupled with the dip-coating approach, followed by annealing at various temperatures from 350 degrees C to 750 degrees C in air. α-Fe 2 O 3 films were characterized by X-ray diffraction, XPS, FE-SEM and electrochemical measurements. The photoelectrochemical performance of α-Fe 2 O 3 photoanodes was characterized and optimized through the deposition of Co-based co-catalysts via different methods (impregnation, electro-deposition and photo-electro-deposition). Interestingly, the resulting hematite films heat-treated at relatively low temperature (500 degrees C), and therefore devoid of any extrinsic dopant, achieve light-driven water oxidation under near-to-neutral (pH = 8) aqueous conditions after decoration with a Co catalyst. The onset potential is 0.75 V vs. the reversible hydrogen electrode (RHE), thus corresponding to 450 mV light-induced under potential, although modest photocurrent density values (40 μAcm -2 ) are obtained below 1.23 V vs. RHE. These new materials with a very large interfacial area in contact with the electrolyte and allowing for a high loading of water oxidation catalysts open new avenues for the optimization of photo-electrochemical water splitting. (authors)

  8. NAD+-Carrying Mesoporous Silica Nanoparticles Can Prevent Oxidative Stress-Induced Energy Failures of Both Rodent Astrocytes and PC12 Cells

    Science.gov (United States)

    Chen, Heyu; Wang, Yao; Zhang, Jixi; Ma, Yingxin; Wang, Caixia; Zhou, Ying; Gu, Hongchen; Ying, Weihai

    2013-01-01

    Aim To test the hypothesis that NAD+-carrying mesoporous silica nanoparticles (M-MSNs@NAD+) can effectively deliver NAD+ into cells to produce cytoprotective effects. Methods & Materials NAD+ was incorporated into M-MSNs. Primary rat astrocyte cultures and PC12 cells were treated with H2O2, followed by post-treatment with M-MSNs@NAD+. After various durations of the post-treatment, intracellular NAD+ levels, intracellular ATP levels and lactate dehydrogenase (LDH) release were determined. Results & Discussion M-MSNs can be effectively loaded with NAD+. The M-MSNs@NAD+ can significantly attenuate H2O2-induced NAD+ and ATP decreases in both astrocyte cultures and PC12 cells. M-MSNs@NAD+ can also partially prevent the H2O2-induced LDH release from both astrocyte cultures and PC12 cells. In contrast, the NAD+ that is spontaneously released from the M-MSNs@NAD+ is insufficient to prevent the H2O2-induced damage. Conclusions Our study has suggested the first approach that can effectively deliver NAD+ into cells, which provides an important basis both for elucidating the roles of intracellular NAD+ in biological functions and for therapeutic applications of NAD+. Our study has also provided the first direct evidence demonstrating a key role of NAD+ depletion in oxidative stress-induced ATP decreases. PMID:24040179

  9. Tungsten-Based Mesoporous Silicates W-MMM-E as Heterogeneous Catalysts for Liquid-Phase Oxidations with Aqueous H2O2

    Directory of Open Access Journals (Sweden)

    Nataliya Maksimchuk

    2018-02-01

    Full Text Available Mesoporous tungsten-silicates, W-MMM-E, have been prepared following evaporation-induced self-assembly methodology and characterized by elemental analysis, XRD, N2 adsorption, STEM-HAADF (high angle annular dark field in scanning-TEM mode, DRS UV-vis, and Raman techniques. DRS UV-vis showed the presence of two types of tungsten oxo-species in W-MMM-E samples: isolated tetrahedrally and oligomeric octahedrally coordinated ones, with the ratio depending on the content of tungsten in the catalyst. Materials with lower W loading have a higher contribution from isolated species, regardless of the preparation method. W-MMM-E catalyzes selectively oxidize of a range of alkenes and organic sulfides, including bulky terpene or thianthrene molecules, using green aqueous H2O2. The selectivity of corresponding epoxides reached 85–99% in up to 80% alkene conversions, while sulfoxides formed with 84–90% selectivity in almost complete sulfide conversions and a 90–100% H2O2 utilization efficiency. The true heterogeneity of catalysis over W-MMM-E was proved by hot filtration tests. Leaching of inactive W species depended on the reaction conditions and initial W loading in the catalyst. After optimization of the catalyst system, it did not exceed 20 ppm and 3 ppm for epoxidation and sulfoxidation reactions, respectively. Elaborated catalysts could be easily retrieved by filtration and reused several times with maintenance of the catalytic behavior.

  10. Limits of ZnO Electrodeposition in Mesoporous Tin Doped Indium Oxide Films in View of Application in Dye-Sensitized Solar Cells

    Directory of Open Access Journals (Sweden)

    Christian Dunkel

    2014-04-01

    Full Text Available Well-ordered 3D mesoporous indium tin oxide (ITO films obtained by a templated sol-gel route are discussed as conductive porous current collectors. This paper explores the use of such films modified by electrochemical deposition of zinc oxide (ZnO on the pore walls to improve the electron transport in dye-sensitized solar cells (DSSCs. Mesoporous ITO film were dip-coated with pore sizes of 20–25 nm and 40–45 nm employing novel poly(isobutylene-b-poly(ethylene oxide block copolymers as structure-directors. After electrochemical deposition of ZnO and sensitization with the indoline dye D149 the films were tested as photoanodes in DSSCs. Short ZnO deposition times led to strong back reaction of photogenerated electrons from non-covered ITO to the electrolyte. ITO films with larger pores enabled longer ZnO deposition times before pore blocking occurred, resulting in higher efficiencies, which could be further increased by using thicker ITO films consisting of five layers, but were still lower compared to nanoporous ZnO films electrodeposited on flat ITO. The major factors that currently limit the application are the still low thickness of the mesoporous ITO films, too small pore sizes and non-ideal geometries that do not allow obtaining full coverage of the ITO surface with ZnO before pore blocking occurs.

  11. Limits of ZnO Electrodeposition in Mesoporous Tin Doped Indium Oxide Films in View of Application in Dye-Sensitized Solar Cells

    Science.gov (United States)

    Dunkel, Christian; von Graberg, Till; Smarsly, Bernd M.; Oekermann, Torsten; Wark, Michael

    2014-01-01

    Well-ordered 3D mesoporous indium tin oxide (ITO) films obtained by a templated sol-gel route are discussed as conductive porous current collectors. This paper explores the use of such films modified by electrochemical deposition of zinc oxide (ZnO) on the pore walls to improve the electron transport in dye-sensitized solar cells (DSSCs). Mesoporous ITO film were dip-coated with pore sizes of 20–25 nm and 40–45 nm employing novel poly(isobutylene)-b-poly(ethylene oxide) block copolymers as structure-directors. After electrochemical deposition of ZnO and sensitization with the indoline dye D149 the films were tested as photoanodes in DSSCs. Short ZnO deposition times led to strong back reaction of photogenerated electrons from non-covered ITO to the electrolyte. ITO films with larger pores enabled longer ZnO deposition times before pore blocking occurred, resulting in higher efficiencies, which could be further increased by using thicker ITO films consisting of five layers, but were still lower compared to nanoporous ZnO films electrodeposited on flat ITO. The major factors that currently limit the application are the still low thickness of the mesoporous ITO films, too small pore sizes and non-ideal geometries that do not allow obtaining full coverage of the ITO surface with ZnO before pore blocking occurs. PMID:28788618

  12. Translational and rotational dynamics of water in mesoporous silica materials: MCM-41-S and MCM-48-S

    International Nuclear Information System (INIS)

    Faraone, Antonio; Liu Li; Mou, C.-Y.; Shih, P.-C.; Copley, John R.D.; Chen, S.-H.

    2003-01-01

    We investigated the translational and rotational dynamics of water molecules in mesoporous silica materials MCM-41-S and MCM-48-S using the incoherent quasielastic neutron scattering technique. The range of wave vector transfers Q covered in the measurements was from 0.27 to 1.93 Aa -1 broad enough to detect both the translational and rotational contributions to the scattering. We used the relaxing-cage models for both translational and rotational motions which we developed earlier, to analyze the QENS spectra and investigated water dynamics in a supercooled range from 250 to 280 K. The results show a marked slowing down of both the translational and rotational relaxation times, and an increasing effect of confinement on the translational motion, as the temperature is lowered

  13. Novel Shape-Stabilized Phase Change Materials Composed of Polyethylene Glycol/Nonsurfactant-Templated Mesoporous Silica: Preparation and Thermal Properties

    Science.gov (United States)

    Chen, Yan; Zhu, Yingying; Wang, Jinbao; Lv, Mengjiao; Zhang, Xiongjie; Gao, Junkai; Zhang, Zijun; Lei, Hao

    2017-12-01

    A novel shape-stabilized phase change material (PEG/TAMS), fabricated using tannic acid-templated mesoporous silica (TAMS) as a support for polyethylene glycol, was developed for thermal energy storage. The method used to synthesize TAMS was simple, cost effective, environmentally friendly, and free of surfactant. The characterization results indicated that PEG was physically absorbed to TAMS and that TAMS had no influence on the crystal structure of PEG. According to the TGA thermograms, PEG/TAMS has excellent thermal stability and can be applied over a wide temperature range. Additionally, the differential scanning calorimetry results suggested that PEG/TAMS has good thermal properties and that its fusion and solidification enthalpies reached 114.7 J/g and 102.4 J/g, respectively. The results indicated that PEG/TAMS has great potential for practical applications.

  14. Mesoporous Fe-containing ZSM-5 zeolite single crystal catalysts for selective catalytic reduction of nitric oxide by ammonia

    DEFF Research Database (Denmark)

    Kustov, Arkadii; Egeblad, Kresten; Kustova, Marina

    2007-01-01

    Mesoporous and conventional Fe-containing ZSM-5 catalysts (0.5–8 wt% Fe) were prepared using a simple impregnationmethod and tested in NO selective catalytic reduction (SCR) with NH3. It was found that mesoporous Fe-ZSM-5 catalysts exhibit higher SCR activities than comparable conventional cataly...

  15. Synthesis and characterization of mesoporous ceria/alumina nanocomposite materials via mixing of the corresponding ceria and alumina gel precursors.

    Science.gov (United States)

    Khalil, Kamal M S

    2007-03-01

    Mesoporous ceria/alumina, CeO(2)/Al(2)O(3), composites containing 10, 20 and 30% (w/w) ceria were prepared by a novel gel mixing method. In the method, ceria gel (formed via hydrolysis of ammonium cerium(IV) nitrate by aqueous ammonium carbonate solution) and alumina gel (formed via controlled hydrolysis of aluminum tri-isopropoxide) were mixed together. The mixed gel was subjected to subsequent drying and calcination for 3 h at 400, 600, 800 and 1000 degrees C. The uncalcined (dried at 110 degrees C) and the calcined composites were investigated by different techniques including TGA, DSC, FTIR, XRD, SEM and nitrogen adsorption/desorption isotherms. Results indicated that composites calcined for 3 h at 800 degrees C mainly kept amorphous alumina structure and gamma-alumina formed only upon calcinations at 1000 degrees C. On the other hand, CeO(2) was found to crystallize in the common ceria, cerinite, phase and it kept this structure over the entire calcination range (400-1000 degrees C). Therefore, high surface areas, stable surface textures, and non-aggregated nano-sized ceria dispersions were obtained. A systematic texture change based on ceria ratio was observed, however in all cases mesoporous composite materials exposing thermally stable texture and structure were obtained. The presented method produces composite ceria/alumina materials that suit different applications in the field of catalysis and membranes technology, and throw some light on physicochemical factors that determine textural morphology and thermal stability of such important composite.

  16. The 2016 oxide electronic materials and oxide interfaces roadmap

    DEFF Research Database (Denmark)

    Lorenz, M.; Rao, M. S. Ramachandra; Venkatesan, T.

    2016-01-01

    of these materials to understand the tunability of their properties and the novel properties that evolve due to their nanostructured nature is another facet of the challenge. The research related to the oxide electronic field is at an impressionable stage, and this has motivated us to contribute with a roadmap......, Pentcheva, and Gegenwart. Finally, Miletto Granozio presents the European action ‘towards oxide-based electronics’ which develops an oxide electronics roadmap with emphasis on future nonvolatile memories and the required technologies.In summary, we do hope that this oxide roadmap appears as an interesting...

  17. Thermochemically active iron titanium oxide materials

    Energy Technology Data Exchange (ETDEWEB)

    Coker, Eric Nicholas; Miller, James E.

    2018-01-16

    A thermal oxidation-reduction cycle is disclosed that uses iron titanium oxide as the reactive material. The cycle may be used for the thermal splitting of water and/or carbon dioxide to form hydrogen and/or carbon monoxide. The formed compounds may be used as syngas precursors to form fuels.

  18. Stability of solid oxide fuel cell materials

    Energy Technology Data Exchange (ETDEWEB)

    Armstrong, T.R.; Bates, J.L.; Chick, L.A. [Pacific Northwest Lab., Richland, WA (United States)

    1996-04-01

    Interconnection materials in a solid oxide fuel cell are exposed to both highly oxidizing conditions at the cathode and to highly reducing conditions at the anode. The thermal expansion characteristics of substituted lanthanum and yttrium chromite interconnect materials were evaluated by dilatometry as a function of oxygen partial pressures from 1 atm to 10{sup -18} atm, controlled using a carbon dioxide/hydrogen buffer.

  19. Effect of Mesoporous Chitosan Action and Coordination on the Catalytic Activity of Mesoporous Chitosan-Grafted Cobalt Tetrakis(p-Sulfophenyl)Porphyrin for Ethylbenzene Oxidation

    OpenAIRE

    Guan Huang; Lin Qiang Mo; Yan Xun Wei; Hong Zhou; Yong An Guo; Su Juan Wei

    2018-01-01

    To simulate the active site cavity structure function and axial coordination of cytochrome P-450 enzymes, mesoporous chitosan(mesp-CTS) was used as a scaffold for a meso-sized cavity to immobilize cobalt tetrakis(p-sulphophenyl)porphyrin chloride(Co TPPS). Immobilization was achieved via an acid–base reaction and axial coordination of the H2N-C group to the Co ion in Co TPPS, thus forming the biomimetic catalyst Co TPPS/mesp-CTS. Several approaches, including scanning electron microscop...

  20. Cerium oxide-deposited mesoporous silica nanoparticles for the determination of carcinoembryonic antigen in serum using inductively coupled plasma-mass spectrometry

    International Nuclear Information System (INIS)

    Choi, H.W.; Lee, K.H.; Hur, N.H.; Lim, H.B.

    2014-01-01

    Highlights: • Sandwich-type immunoassay using ICP-MS and nanoparticles to determine biomarkers. • CeO 2 -deposited mesoporous silica nanoparticles were synthesized as a probe. • Ratiometric measurement significantly improved the calibration linearity. • Excellent detection limit was achieved by signal amplification. - Abstract: CeO 2 -deposited mesoporous silica nanoparticles were synthesized as a probe to determine carcinoembryonic antigen (CEA) in serum by inductively coupled plasma-mass spectrometry (ICP-MS). The prepared mesoporous nanoparticles were modified and tagged to the target for sandwich-type immunoassay. Fe 3 O 4 magnetic nanoparticles (MNPs) were also synthesized and immobilized with antibody to extract the target biomarker. The calibration curve of the synthesized CeO 2 -deposited silica nanoparticles, which was plotted by the signal ratio of 140 Ce/ 57 Fe measured by ICP-MS vs. the concentration of CEA, showed excellent linearity and sensitivity owing to the signal amplification and low spectral interference. Under optimal conditions, the sandwich-type analytical method was applied to determine CEA in serum spiked in the range of 0.001–5 ng mL −1 and showed a limit of detection of 0.36 ng mL −1 . Since the deposited CeO 2 in the mesoporous silica layer can be substituted by other metal compounds, various kinds of metal-deposited nanoparticles can be prepared as probe materials for multiplex detection in bioanalysis

  1. Preparation of novel oxidized mesoporous carbon with excellent adsorption performance for removal of malachite green and lead ion

    Science.gov (United States)

    Zhang, Xialan; Lin, Qilang; Luo, Shiyuan; Ruan, Kezhao; Peng, Kaiping

    2018-06-01

    An oxidized mesoporous carbon (OMC) with fluffy structure was fabricated from the mixture of petroleum asphalt and aluminum isopropoxide, and its structures were characterized by FESEM, TEM, BET, TG, XPS and FT-IR. In addition, bath absorption experiments for malachite green (MG) and lead ion (Pb2+) were carried out to explore the effects of pH, initial concentration, contact time and temperature on its absorption process. Results show that the OMC prepared has a fluffy ultrathin-wall structure with narrow pore size distribution and rich oxygen-containing groups. It exhibits excellent absorption performance for the removal of MG as well as Pb2+, as indicated by that its maximum adsorption capacity is 963.1 mg g-1 for MG and 198.6 mg g-1 for Pb2+. The absorption experimental data are all fitted well with pseudo-second-order model and Frendlich isotherm, respectively. More importantly, the OMC still maintains relatively high adsorption capacity after five cycles.

  2. Targeted Mesoporous Iron Oxide Nanoparticles-Encapsulated Perfluorohexane and a Hydrophobic Drug for Deep Tumor Penetration and Therapy.

    Science.gov (United States)

    Su, Yu-Lin; Fang, Jen-Hung; Liao, Chia-Ying; Lin, Chein-Ting; Li, Yun-Ting; Hu, Shang-Hsiu

    2015-01-01

    A magneto-responsive energy/drug carrier that enhances deep tumor penetration with a porous nano-composite is constructed by using a tumor-targeted lactoferrin (Lf) bio-gate as a cap on mesoporous iron oxide nanoparticles (MIONs). With a large payload of a gas-generated molecule, perfluorohexane (PFH), and a hydrophobic anti-cancer drug, paclitaxel (PTX), Lf-MIONs can simultaneously perform bursting gas generation and on-demand drug release upon high-frequency magnetic field (MF) exposure. Biocompatible PFH was chosen and encapsulated in MIONs due to its favorable phase transition temperature (56 °C) and its hydrophobicity. After a short-duration MF treatment induces heat generation, the local pressure increase via the gasifying of the PFH embedded in MION can substantially rupture the three-dimensional tumor spheroids in vitro as well as enhance drug and carrier penetration. As the MF treatment duration increases, Lf-MIONs entering the tumor spheroids provide an intense heat and burst-like drug release, leading to superior drug delivery and deep tumor thermo-chemo-therapy. With their high efficiency for targeting tumors, Lf-MIONs/PTX-PFH suppressed subcutaneous tumors in 16 days after a single MF exposure. This work presents the first study of using MF-induced PFH gasification as a deep tumor-penetrating agent for drug delivery.

  3. 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.

  4. Surface functionalization of mesoporous antimony doped tin oxide by metalorganic reaction

    Czech Academy of Sciences Publication Activity Database

    Müller, V.; Haase, F.; Rathouský, Jiří; Fattakhova-Rohlfing, D.

    2012-01-01

    Roč. 137, č. 1 (2012), s. 207-212 ISSN 0254-0584 Institutional support: RVO:61388955 Keywords : oxides * organometallic compounds * chemical synthesis Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.072, year: 2012

  5. Immobilization of Lactobacillus rhamnosus in mesoporous silica-based material: An efficiency continuous cell-recycle fermentation system for lactic acid production.

    Science.gov (United States)

    Zhao, Zijian; Xie, Xiaona; Wang, Zhi; Tao, Yanchun; Niu, Xuedun; Huang, Xuri; Liu, Li; Li, Zhengqiang

    2016-06-01

    Lactic acid bacteria immobilization methods have been widely used for lactic acid production. Until now, the most common immobilization matrix used is calcium alginate. However, Ca-alginate gel disintegrated during lactic acid fermentation. To overcome this deficiency, we developed an immobilization method in which Lactobacillus rhamnosus cells were successfully encapsulated into an ordered mesoporous silica-based material under mild conditions with a high immobilization efficiency of 78.77% by using elemental analysis. We also optimized the cultivation conditions of the immobilized L. rhamnosus and obtained a high glucose conversion yield of 92.4%. Furthermore, L. rhamnosus encapsulated in mesoporous silica-based material exhibited operational stability during repeated fermentation processes and no decrease in lactic acid production up to 8 repeated batches. Copyright © 2016 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  6. Shape-Enhanced Photocatalytic Activities of Thoroughly Mesoporous ZnO Nanofibers

    KAUST Repository

    Ren, Xiaolong

    2016-06-24

    1D mesoporous materials have attracted extensive interest recently, owning to their fascinating properties and versatile applications. However, it remains as a grand challenge to develop a simple and efficient technique to produce oxide nanofibers with mesoporous architectures, controlled morphologies, large surface areas, and optimal performances. In this work, a facile foaming-assisted electrospinning strategy with foaming agent of tea saponin is used to produce thoroughly mesoporous ZnO nanofibers with high purity and controlled morphology. Interestingly, mesoporous fibers with elliptical cross-section exhibit the significantly enhanced photocatalytic activity for hydrogen production, as compared to the counterparts with circular and rectangular cross-sections, and they also perform better than the commercial ZnO nanopowders. The unexpected shape dependence of photocatalytic activities is attributed to the different stacking modes of the mesoporous fibers, and a geometrical model is developed to account for the shape dependence. This work represents an important step toward producing thoroughly mesoporous ZnO nanofibers with tailored morphologies, and the discovery that fibers with elliptical cross-section render the best performance provides a valuable guideline for improving the photocatalytic performance of such mesoporous nanomaterials. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Nanocasted synthesis of magnetic mesoporous iron cerium bimetal oxides (MMIC) as an efficient heterogeneous Fenton-like catalyst for oxidation of arsenite

    Energy Technology Data Exchange (ETDEWEB)

    Wen, Zhipan [State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092 (China); Zhang, Yalei, E-mail: zhangyalei@tongji.edu.cn [State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092 (China); Dai, Chaomeng [College of Civil Engineering, Tongji University, Shanghai 200092 (China); Sun, Zhen [State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092 (China)

    2015-04-28

    Highlights: • MMIC with large surface area and pore volume was synthesized via the hard template. • MMIC could be easily separated from aqueous solution with an external magnetic field. • MMIC presented excellent catalytic activity for the oxidation of As(III). • As(III) was mainly oxidized by surface-bound ·OH{sub ads} and free ·OH{sub free} radicals. • MMIC played a dual function role for the arsenic removal in aqueous solution. - Abstract: Magnetic mesoporous iron cerium bimetal oxides (MMIC) with large surface area and pore volume was synthesized via the hard template approach. This obtained MMIC was easily separated from aqueous solution with an external magnetic field and was proposed as a heterogeneous Fenton-like catalyst for oxidation of As(III). The MMIC presented excellent catalytic activity for the oxidation of As(III), achieving almost complete oxidation of 1000 ppb As(III) after 60 min and complete removal of arsenic species after 180 min with reaction conditions of 0.4 g/L catalyst, pH of 3.0 and 0.4 mM H{sub 2}O{sub 2}. Kinetics analysis showed that arsenic removal followed the pseudo-first order, and the pseudo-first-order rate constants increased from 0.0014 min{sup −1} to 0.0548 min{sup −1} as the H{sub 2}O{sub 2} concentration increased from 0.04 mM to 0.4 mM. On the basis of the effects of XPS analysis and reactive oxidizing species, As(III) in aqueous solution was mainly oxidized by ·OH radicals, including the surface-bound ·OH{sub ads} generated on the MMIC surface which were involved in ≡Fe{sup 2+} and ≡Ce{sup 3+}, and free ·OH{sub free} generation by soluble iron ions which were released from the MMIC into the bulk solution, and the generated As(V) was finally removed by MMIC through adsorption.

  8. Enhanced thermal properties of novel shape-stabilized PEG composite phase change materials with radial mesoporous silica sphere for thermal energy storage

    OpenAIRE

    Min, Xin; Fang, Minghao; Huang, Zhaohui; Liu, Yan?gai; Huang, Yaoting; Wen, Ruilong; Qian, Tingting; Wu, Xiaowen

    2015-01-01

    Radial mesoporous silica (RMS) sphere was tailor-made for further applications in producing shape-stabilized composite phase change materials (ss-CPCMs) through a facile self-assembly process using CTAB as the main template and TEOS as SiO2 precursor. Novel ss-CPCMs composed of polyethylene glycol (PEG) and RMS were prepared through vacuum impregnating method. Various techniques were employed to characterize the structural and thermal properties of the ss-CPCMs. The DSC results indicated that...

  9. Core-shelled mesoporous CoFe2O4-SiO2 material with good adsorption and high-temperature magnetic recycling capabilities

    Science.gov (United States)

    Li, Zhi'ang; Wang, Jianlin; Liu, Min; Chen, Tong; Chen, Jifang; Ge, Wen; Fu, Zhengping; Peng, Ranran; Zhai, Xiaofang; Lu, Yalin

    2018-04-01

    Residues of organic dye in industrial effluents cause severe water system pollution. Although several methods, such as biodegradation and activated carbon adsorption, are available for treating these effluents before their discharge into waterbodies, secondary pollution by adsorbents and degrading products remains an issue. Therefore, new materials should be identified to solve this problem. In this work, CoFe2O4-SiO2 core-shell structures were synthesized using an improved Stöber method by coating mesoporous silica onto CoFe2O4 nanoparticles. The specific surface areas of the synthesized particles range from 30 m2/g to 150 m2/g and vary according to the dosage amount of tetraethoxysilane. Such core-shelled nanoparticles have the following advantages for treating industrial effluents mixed with dye: good adsorption capability, above-room-temperature magnetic recycling capability, and heat-enduring stability. Through adsorption of methylene blue, a typical dyeing material, the core-shell-structured particles show a good adsorption capability of approximately 33 mg/L. The particles are easily and completely collected by magnets, which is possible due to the magnetic property of core CoFe2O4. Heat treatment can burn out the adsorbed dyes and good adsorption performance is sustained even after several heat-treating loops. This property overcomes the common problem of particles with Fe3O4 as a core, by which Fe3O4 is oxidized to nonmagnetic α-Fe2O3 at the burning temperature. We also designed a miniature of effluent-treating pipeline, which demonstrates the potential of the application.

  10. Immobilization of cholesterol esterase in mesoporous silica materials and its hydrolytic activity toward diethyl phthalate

    Energy Technology Data Exchange (ETDEWEB)

    Orita, Toru, E-mail: nqj45366@nifty.com [Division of Chemistry for Materials, Graduate School of Engineering, Mie University, 1577 Kurimamachiya-cho, Tsu, Mie 514-8570 (Japan); Taiyo Kagaku Co. Ltd., 800 Yamada-cho, Yokkaichi, Mie 512-1111 (Japan); Tomita, Masahiro [Division of Chemistry for Materials, Graduate School of Engineering, Mie University, 1577 Kurimamachiya-cho, Tsu, Mie 514-8570 (Japan); Saito, Takao; Nishida, Nasakazu; Kato, Katsuya [National Institute of Advanced Industrial Science and Technology, 2266-78 Anagahora, Moriyamaku, Nagoya, Aichi 463-8560 (Japan)

    2012-05-01

    Cholesterol esterase (CE, cholesteryl ester hydrolase, EC 3.1.1.13) from porcine pancreas (molecular weight 400-500 kDa) exhibits hydrolytic activity toward various toxic organic phthalate esters. CE was confined in the nanospace (diameter 3-30 nm) of five types of mesoporous silica (MPS) that differ in structural properties such as pore diameter, pore volume, and particle morphology. These structural properties were characterized by transmission electron microscopy, small-angle X-ray diffraction, N{sub 2} adsorption-desorption experiments, solid-state {sup 13}C nuclear magnetic resonance (NMR), and solid-state {sup 29}Si NMR. Catalytic activities of immobilized and free CE were evaluated by the hydrolysis of diethyl phthalate in phosphate buffer solutions containing an organic cosolvent. Optimal activity recovery was achieved when CE was immobilized in n-decane-functionalized MPS, which had a large pore size (22.5 nm). The immobilization also protected against effects of temperature within the range 30 Degree-Sign C-60 Degree-Sign C; CE immobilized in n-decyl-functionalized MPS exhibited better thermal stability than in non-functionalized MPS or free CE. Moreover, it retained approximately 60% of its catalytic activity even after six catalytic cycles. - Highlights: Black-Right-Pointing-Pointer The highest activity of immobilized CE was shown in MPS with a pore size of 22.5 nm. Black-Right-Pointing-Pointer Catalytic efficiency improved when MPS was functionalized by n-decyl substitution. Black-Right-Pointing-Pointer Immobilized CE exhibited good thermal stability and reusability. Black-Right-Pointing-Pointer Organic co-solvent and the substrate structures affected enzyme activities.

  11. A highly sensitive and durable electrical sensor for liquid ethanol using thermally-oxidized mesoporous silicon

    Science.gov (United States)

    Harraz, Farid A.; Ismail, Adel A.; Al-Sayari, S. A.; Al-Hajry, A.; Al-Assiri, M. S.

    2016-12-01

    A capacitive detection of liquid ethanol using reactive, thermally oxidized films constructed from electrochemically synthesized porous silicon (PSi) is demonstrated. The sensor elements are fabricated as meso-PSi (pore sizes hydrophobic PSi surface exhibited almost a half sensitivity of the thermal oxide sensor. The response to water is achieved only at the oxidized surface and found to be ∼one quarter of the ethanol sensitivity, dependent on parameters such as vapor pressure and surface tension. The capacitance response retains ∼92% of its initial value after continuous nine cyclic runs and the sensors presumably keep long-term stability after three weeks storage, demonstrating excellent durability and storage stability. The observed behavior in current system is likely explained by the interface interaction due to dipole moment effect. The results suggest that the current sensor structure and design can be easily made to produce notably higher sensitivities for reversible detection of various analytes.

  12. Nanoscale materials in chemistry

    National Research Council Canada - National Science Library

    Klabunde, Kenneth J; Richards, Ryan

    2009-01-01

    ...: Disordered, Porous Nanostructures Stephanie L. Brock 209 9 Ordered Microporous and Mesoporous Materials Freddy Kleitz 243 10 Applications of Microporous and Mesoporous Materials Anirban Ghosh,...

  13. Mesoporous Silica: A Suitable Adsorbent for Amines

    Directory of Open Access Journals (Sweden)

    Abdollahzadeh-Ghom Sara

    2009-01-01

    Full Text Available Abstract Mesoporous silica with KIT-6 structure was investigated as a preconcentrating material in chromatographic systems for ammonia and trimethylamine. Its adsorption capacity was compared to that of existing commercial materials, showing its increased adsorption power. In addition, KIT-6 mesoporous silica efficiently adsorbs both gases, while none of the employed commercial adsorbents did. This means that KIT-6 Mesoporous silica may be a good choice for integrated chromatography/gas sensing micro-devices.

  14. 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.

  15. Oxidation rate in ferritic superheater materials

    International Nuclear Information System (INIS)

    Falk, I.

    1992-05-01

    On the steam side of superheater tubes, compact oxide layers are formed which have a tendency to crack and flake off (exfoliate). Oxide particles then travel with the steam and can give rise to erosion damage in valves and on turbine blades. In an evaluation of conditions in superheater tubes from Swedish power boilers, it was found that the exfoliation frequency for one material quality (SS 2218) was greater than for other qualities. Against this background, a literature study has been carried out in order to determine which mechanisms govern the build-up of oxide and the exfoliation phenomenon. The study reveals that the oxide morphology is similar on all ferritic steels with Cr contents up to 5%. and that the oxide properties can therefore be expected to be similar. The reason why the exfoliation frequency is greater for tubes of SS 2218 is probably that the tubes have been exposed to higher temperatures. SS 2218 (2.25 Cr) is normally used in a higher temperature range which is accompanied by improved strength data as compared with SS 2216 (1 Cr). The principal cause of the exfoliation is said to be stresses which arise in the oxide during the cooling-down process associated with shutdowns. The stresses give rise to longitudinal cracks in the oxide, and are formed as a result of differences in thermal expansion between the oxide and the tube material. In addition, accounts are presented of oxidation constants and growth velocities, and thickness and running time. These data constitute a valuable basis for practical estimates of the operating temperature in routine checks and investigations into damage in superheater tubes. (au)

  16. Oxide bipolar electronics: materials, devices and circuits

    International Nuclear Information System (INIS)

    Grundmann, Marius; Klüpfel, Fabian; Karsthof, Robert; Schlupp, Peter; Schein, Friedrich-Leonhard; Splith, Daniel; Yang, Chang; Bitter, Sofie; Von Wenckstern, Holger

    2016-01-01

    We present the history of, and the latest progress in, the field of bipolar oxide thin film devices. As such we consider primarily pn-junctions in which at least one of the materials is a metal oxide semiconductor. A wide range of n-type and p-type oxides has been explored for the formation of such bipolar diodes. Since most oxide semiconductors are unipolar, challenges and opportunities exist with regard to the formation of heterojunction diodes and band lineups. Recently, various approaches have led to devices with high rectification, namely p-type ZnCo 2 O 4 and NiO on n-type ZnO and amorphous zinc-tin-oxide. Subsequent bipolar devices and applications such as photodetectors, solar cells, junction field-effect transistors and integrated circuits like inverters and ring oscillators are discussed. The tremendous progress shows that bipolar oxide electronics has evolved from the exploration of various materials and heterostructures to the demonstration of functioning integrated circuits. Therefore a viable, facile and high performance technology is ready for further exploitation and performance optimization. (topical review)

  17. 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.

  18. Preparation of oxide materials from metal alkoxides

    International Nuclear Information System (INIS)

    Turevskaya, E.P.; Turova, N.Ya.; Yanovskaya, M.I.

    2000-01-01

    The results of studies on the sol-gel technologies on the basis of alkoxides are presented. The synthesis and properties of titanates zirconates, niobates, tantalates, vanadates and solid solutions on the basis of Mo, W and Bi oxides, iron oxides and high-temperature superconductors are presented. The most important aspects, determining the choice of optimal conditions for preparation of oxides of concrete compositions with required properties are pointed out. Accomplishment of the whole chain of studies made it possible to synthesize a broad range of metal alkoxides and study their properties and also carry out large-scale studies on preparation of various oxides and materials on the basis thereof, using the source base of the sol-gel method [ru

  19. Sea urchin-like mesoporous carbon material grown with carbon nanotubes as a cathode catalyst support for fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Kuo, Ping-Lin; Hsu, Chun-Han; Li, Wan-Ting; Jhan, Jing-Yi; Chen, Wei-Fu [Department of Chemical Engineering, National Cheng Kung University, Tainan 70101 (China)

    2010-12-15

    A sea urchin-like carbon (UC) material with high surface area (416 m{sup 2} g{sup -1}), adequate electrical conductivity (59.6 S cm{sup -1}) and good chemical stability was prepared by growing carbon nanotubes onto mesoporous carbon hollow spheres. A uniform dispersion of Pt nanoparticles was then anchored on the UC, where the Pt nanoparticles were prepared using benzylamine as the stabilizer. For this Pt loaded carbon, cyclic voltammogram measurements showed an exceptionally high electrochemically active surface area (EAS) (114.8 m{sup 2} g{sup -1}) compared to the commonly used commercial E-TEK catalyst (65.2 m{sup 2} g{sup -1}). The durability test demonstrates that the carbon used as a support exhibited minor loss in EAS of Pt. Compared to the E-TEK (20 wt%) cathode catalyst, this Pt loaded UC catalyst has greatly enhanced catalytic activity toward the oxygen reduction reaction, less cathode flooding and considerably improved performance, resulting in an enhancement of ca. 37% in power density compared with that of E-TEK. Based on the results obtained, the UC is an excellent support for Pt nanoparticles used as cathode catalysts in proton exchange membrane fuel cells. (author)

  20. Performance of LiCl Impregnated Mesoporous Material Coating over Corrugated Heat Exchangers in a Solid Sorption Chiller

    Directory of Open Access Journals (Sweden)

    Hongzhi Liu

    2018-06-01

    Full Text Available The composite material made by impregnating 40 wt. % lithium chloride (LiCl into the mesopores of a kind of natural porous rock (Wakkanai Siliceous Shale: WSS micropowders (short for “WSS + 40 wt. % LiCl” had been developed previously, and can be regenerated below 100 °C with a cooling coefficient of performance (COP of approximately 0.3 when adopted as a sorbent in a sorption cooler. In this study, experiments have been carried out on an intermittent solid sorption chiller with the WSS + 40 wt. % LiCl coating over two aluminum corrugated heat exchangers. Based on the experimental condition (regeneration temperature of 80 °C, condensation temperature of 30 °C in the desorption process; sorption temperature of 30 °C and evaporation temperature of 12 °C in the sorption process, the water sorption amount changes from 20 wt. % to 70 wt. % in one sorption cooling cycle. Moreover, a specific cooling power (SCP of 86 W/kg, a volumetric specific cooling power (VSCP of 42 W/dm3, and a specific sorption power of 170 W/kg can be achieved with a total sorption and desorption time of 20 min. The obtained cooling COP is approximately 0.16.

  1. 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

  2. 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.

  3. Self-immobilization of acidogenic mixed consortia on mesoporous material (SBA-15) and activated carbon to enhance fermentative hydrogen production

    Energy Technology Data Exchange (ETDEWEB)

    Mohan, S. Venkata; Mohanakrishna, G.; Sarma, P.N. [Bioengineering and Environmental Centre, Indian Institute of Chemical Technology, Hyderabad 500607 (India); Reddy, S. Sreevardhan; Raju, B. David; Rao, K.S. Rama [Catalysis and Physical Chemistry Division, Indian Institute of Chemical Technology, Hyderabad 500607 (India)

    2008-11-15

    The influence of self-immobilization of enriched acidogenic mixed consortia on fermentative hydrogen (H{sub 2}) production was studied on different supporting materials [SBA-15 (mesoporous) and activated carbon (granular; GAC and powder; PAC)] using chemical wastewater as substrate. Batch fermentation experiments were performed with same substrate at different organic loading rates (OLRs) under acidophilic microenvironment (pH 5.5) and room temperature (28 {+-} 2 C). Experimental data evidenced the effectiveness of attached growth on both the H{sub 2} yields and substrate degradation efficiency, particularly at higher loading rates. Among the three materials evaluated, immobilization on SBA-15 material showed comparatively effective performance in enhancing both H{sub 2} yield and substrate degradation. Suspended growth (SG-control) culture showed inhibition in terms of both H{sub 2} production and substrate degradation especially at applied higher loading rates. Immobilization on SBA-15 resulted in nine times higher H{sub 2} production (7.29 mol/kg COD{sub R}-day at OLR of 0.83 kg COD/m{sup 3}-day) than the lowest yield observed (suspended growth at OLR of 2.55 kg COD/m{sup 3}-day). Maximum substrate degradation rate (SDR) of 0.96 kg COD/m{sup 3}-day (OLR 2.55 kg COD/m{sup 3}-day) was also observed with SBA-15 immobilization, which is 1.62 times higher than the lowest substrate degradation observed with SG-control experiments with the same OLR. Attached growth on GAC and PAC also showed remarkable improvement in the process performance at higher OLRs compared to SG-control. (author)

  4. Cerium oxide-deposited mesoporous silica nanoparticles for the determination of carcinoembryonic antigen in serum using inductively coupled plasma-mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Choi, H.W. [Department of Chemistry, NSBI, Dankook University, 126 Jukjeon-dong, Suji-gu, Yongin-si, Gyeonggi-do 448-701 (Korea, Republic of); Lee, K.H.; Hur, N.H. [Department of Chemistry, Sogang University, Shinsu-dong, Mapo-gu, Seoul (Korea, Republic of); Lim, H.B., E-mail: plasma@dankook.ac.kr [Department of Chemistry, NSBI, Dankook University, 126 Jukjeon-dong, Suji-gu, Yongin-si, Gyeonggi-do 448-701 (Korea, Republic of)

    2014-10-17

    Highlights: • Sandwich-type immunoassay using ICP-MS and nanoparticles to determine biomarkers. • CeO{sub 2}-deposited mesoporous silica nanoparticles were synthesized as a probe. • Ratiometric measurement significantly improved the calibration linearity. • Excellent detection limit was achieved by signal amplification. - Abstract: CeO{sub 2}-deposited mesoporous silica nanoparticles were synthesized as a probe to determine carcinoembryonic antigen (CEA) in serum by inductively coupled plasma-mass spectrometry (ICP-MS). The prepared mesoporous nanoparticles were modified and tagged to the target for sandwich-type immunoassay. Fe{sub 3}O{sub 4} magnetic nanoparticles (MNPs) were also synthesized and immobilized with antibody to extract the target biomarker. The calibration curve of the synthesized CeO{sub 2}-deposited silica nanoparticles, which was plotted by the signal ratio of {sup 140}Ce/{sup 57}Fe measured by ICP-MS vs. the concentration of CEA, showed excellent linearity and sensitivity owing to the signal amplification and low spectral interference. Under optimal conditions, the sandwich-type analytical method was applied to determine CEA in serum spiked in the range of 0.001–5 ng mL{sup −1} and showed a limit of detection of 0.36 ng mL{sup −1}. Since the deposited CeO{sub 2} in the mesoporous silica layer can be substituted by other metal compounds, various kinds of metal-deposited nanoparticles can be prepared as probe materials for multiplex detection in bioanalysis.

  5. In situ synthesis of N and Cu functionalized mesoporous FDU-14 resins and carbons for electrochemical hydrogen storage

    Energy Technology Data Exchange (ETDEWEB)

    Kong, AiGuo; Wang, WenJuan; Yang, Fan; Ding, HanMing; Shan, YongKui [Department of Chemistry, East China Normal University, ShangHai 200062 (China)

    2010-07-15

    N and Cu cooperatively functionalized mesoporous resin and carbon materials with bicontinuous cubic structure (FDU-14) were obtained by a novel synthesis method. In this method, block copolymers were used as the templates as well as the precursors for the preparation of these modifying mesoporous materials. The CuC{sub 2}O{sub 4} in the channels of mesoporous FDU-14 resins was gotten by in situ oxidation of the templates in a catalytic redox system containing Cu{sup 2+}, Al{sup 3+}, NO{sub 3}{sup -}, PO{sub 4}{sup 3-}, SO{sub 4}{sup 2-} ions. Simultaneously, the phenol-formaldehyde resin frameworks were in situ functionalized by the amine group resulting from the reduction of NO{sub 3}{sup -}, leading to the formation of N and CuC{sub 2}O{sub 4} modified mesoporous FDU-14 resin materials. Its pyrolysis at the different temperatures resulted in the production of N and Cu cooperatively functionalized mesoporous FDU-14 resin and carbon materials. The structure and composition of these materials were characterized by the X-ray power diffraction, transmission electron microscopy, N{sub 2} adsorption-desorption analysis, X-ray photoelectron spectroscopy, infrared spectroscopy, thermogravimetry analysis, and inductive coupled plasma emission spectroscopy. The electrochemical measurement indicated that N and Cu cooperatively functionalized mesoporous FDU-14 carbon materials possessed the enhanced electrochemical hydrogen storage performance. (author)

  6. 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

  7. Transparent oxide electronics from materials to devices

    CERN Document Server

    Martins, Rodrigo; Barquinha, Pedro; Pereira, Luis

    2012-01-01

    Transparent electronics is emerging as one of the most promising technologies for the next generation of electronic products, away from the traditional silicon technology. It is essential for touch display panels, solar cells, LEDs and antistatic coatings. The book describes the concept of transparent electronics, passive and active oxide semiconductors, multicomponent dielectrics and their importance for a new era of novel electronic materials and products. This is followed by a short history of transistors, and how oxides have revolutionized this field. It concludes with a glance at lo

  8. Type I Collagen and Strontium-Containing Mesoporous Glass Particles as Hybrid Material for 3D Printing of Bone-Like Materials.

    Science.gov (United States)

    Montalbano, Giorgia; Fiorilli, Sonia; Caneschi, Andrea; Vitale-Brovarone, Chiara

    2018-04-28

    Bone tissue engineering offers an alternative promising solution to treat a large number of bone injuries with special focus on pathological conditions, such as osteoporosis. In this scenario, the bone tissue regeneration may be promoted using bioactive and biomimetic materials able to direct cell response, while the desired scaffold architecture can be tailored by means of 3D printing technologies. In this context, our study aimed to develop a hybrid bioactive material suitable for 3D printing of scaffolds mimicking the natural composition and structure of healthy bone. Type I collagen and strontium-containing mesoporous bioactive glasses were combined to obtain suspensions able to perform a sol-gel transition under physiological conditions. Field emission scanning electron microscopy (FESEM) analyses confirmed the formation of fibrous nanostructures homogeneously embedding inorganic particles, whereas bioactivity studies demonstrated the large calcium phosphate deposition. The high-water content promoted the strontium ion release from the embedded glass particles, potentially enhancing the osteogenic behaviour of the composite. Furthermore, the suspension printability was assessed by means of rheological studies and preliminary extrusion tests, showing shear thinning and fast material recovery upon deposition. In conclusion, the reported results suggest that promising hybrid systems suitable for 3D printing of bioactive scaffolds for bone tissue engineering have been developed.

  9. Surface PEGylation of mesoporous silica materials via surface-initiated chain transfer free radical polymerization: Characterization and controlled drug release.

    Science.gov (United States)

    Huang, Long; Liu, Meiying; Mao, Liucheng; Huang, Qiang; Huang, Hongye; Wan, Qing; Tian, Jianwen; Wen, Yuanqing; Zhang, Xiaoyong; Wei, Yen

    2017-12-01

    As a new type of mesoporous silica materials with large pore diameter (pore size between 2 and 50nm) and high specific surface areas, SBA-15 has been widely explored for different applications especially in the biomedical fields. The surface modification of SBA-15 with functional polymers has demonstrated to be an effective way for improving its properties and performance. In this work, we reported the preparation of PEGylated SBA-15 polymer composites through surface-initiated chain transfer free radical polymerization for the first time. The thiol group was first introduced on SBA-15 via co-condensation with γ-mercaptopropyltrimethoxysilane (MPTS), that were utilized to initiate the chain transfer free radical polymerization using poly(ethylene glycol) methyl ether methacrylate (PEGMA) and itaconic acid (IA) as the monomers. The successful modification of SBA-15 with poly(PEGMA-co-IA) copolymers was evidenced by a series of characterization techniques, including 1 H NMR, FT-IR, TGA and XPS. The final SBA-15-SH- poly(PEGMA-co-IA) composites display well water dispersity and high loading capability towards cisplatin (CDDP) owing to the introduction of hydrophilic PEGMA and carboxyl groups. Furthermore, the CDDP could be released from SBA-15-SH-poly(PEGMA-co-IA)-CDDP complexes in a pH dependent behavior, suggesting the potential controlled drug delivery of SBA-15-SH-poly(PEGMA-co-IA). More importantly, the strategy should be also useful for fabrication of many other functional materials for biomedical applications owing to the advantages of SBA-15 and well monomer adoptability of chain transfer free radical polymerization. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. 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.

  11. Controlled synthesis of the tricontinuous mesoporous material IBN-9 and its carbon and platinum derivatives

    KAUST Repository

    Zhao, Yunfeng; Zhang, Daliang; Zhao, Lan; Wang, Guangchao; Zhu, Yihan; Cairns, Amy; Sun, Junliang; Zou, Xiaodong; Han, Yu

    2011-01-01

    materials (e.g., carbon and platinum) via a "hard- templating" synthesis route. The obtained carbon material possesses large surface area (∼1900 m2/g), high pore volume (1.56 cm 3/g), and remarkable gas adsorption capability at both cryogenic temperatures

  12. Nitrogen enriched mesoporous organic polymer anchored copper(II) material: an efficient and reusable catalyst for the synthesis of esters and amides from aromatic systems.

    Science.gov (United States)

    Molla, Rostam Ali; Iqubal, Md Asif; Ghosh, Kajari; Kamaluddin; Islam, Sk Manirul

    2015-04-14

    A new copper-grafted mesoporous poly-melamine-formaldehyde (Cu-mPMF) has been synthesized from melamine and paraformaldehyde in DMSO medium, followed by grafting of Cu(ii) at its surface. Cu-mPMF has been characterized by elemental analysis, powder XRD, HR TEM, FE-SEM, N2 adsorption study, FT-IR, UV-vis DRS, TGA-DTA, EPR spectroscopy, Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). The Cu-grafted mesoporous material showed very good catalytic activity in methyl esterification of benzylic alcohols and amidation of nitriles. Moreover, the catalyst is easily recoverable and can be reused seven times without appreciable loss of catalytic activity in the above reactions. The highly dispersed and strongly bound Cu(ii) sites in the Cu-grafted mesoporous polymer could be responsible for the observed high activities of the Cu-mPMF catalyst. Due to strong binding with the functional groups of the polymer, no evidence of leached copper from the catalyst during the course of reaction emerged, suggesting true heterogeneity in the catalytic process.

  13. Mesoporous carbon-coated LiFePO4 nanocrystals co-modified with graphene and Mg2+ doping as superior cathode materials for lithium ion batteries.

    Science.gov (United States)

    Wang, Bo; Xu, Binghui; Liu, Tiefeng; Liu, Peng; Guo, Chenfeng; Wang, Shuo; Wang, Qiuming; Xiong, Zhigang; Wang, Dianlong; Zhao, X S

    2014-01-21

    In this work, mesoporous carbon-coated LiFePO4 nanocrystals further co-modified with graphene and Mg(2+) doping (G/LFMP) were synthesized by a modified rheological phase method to improve the speed of lithium storage as well as cycling stability. The mesoporous structure of LiFePO4 nanocrystals was designed and realized by introducing the bead milling technique, which assisted in forming sucrose-pyrolytic carbon nanoparticles as the template for generating mesopores. For comparison purposes, samples modified only with graphene (G/LFP) or Mg(2+) doping (LFMP) as well as pure LiFePO4 (LFP) were also prepared and investigated. Microscopic observation and nitrogen sorption analysis have revealed the mesoporous morphologies of the as-prepared composites. X-ray diffraction (XRD) and Rietveld refinement data demonstrated that the Mg-doped LiFePO4 is a single olivine-type phase and well crystallized with shortened Fe-O and P-O bonds and a lengthened Li-O bond, resulting in an enhanced Li(+) diffusion velocity. Electrochemical properties have also been investigated after assembling coin cells with the as-prepared composites as the cathode active materials. Remarkably, the G/LFMP composite has exhibited the best electrochemical properties, including fast lithium storage performance and excellent cycle stability. That is because the modification of graphene provided active sites for nuclei, restricted the in situ crystallite growth, increased the electronic conductivity and reduced the interface reaction current density, while, Mg(2+) doping improved the intrinsically electronic and ionic transfer properties of LFP crystals. Moreover, in the G/LFMP composite, the graphene component plays the role of "cushion" as it could quickly realize capacity response, buffering the impact to LFMP under the conditions of high-rate charging or discharging, which results in a pre-eminent rate capability and cycling stability.

  14. The effect of gallium supported on mesoporous silica and its catalytic activity for oxidation of benzene, toluene and o-xylene

    Energy Technology Data Exchange (ETDEWEB)

    Schwanke, A.J.; Pergher, S.; Probst, L.F.D. [Universidade Federal do Rio Grande do Norte (UFRN), RN (Brazil); Balzer, R. [Universidade Federal do Parana (UFPR), PR (Brazil)

    2016-07-01

    Full text: Benzene, toluene and xylene (BTX) are a particular class of volatile organic compounds, which are highly toxic pollutants. In this study, samples of gallium-containing mesoporous silica (MS-Ga7% and MS-Ga11%) were synthesized and their catalytic activity in the oxidation of BTX was investigated. The physicochemical characterization by XRD, XPS, XRF, nitrogen adsorption and desorption isotherms at 77K, FTIR, SEM and TEM shows that the inclusion of gallium in the mesoporous silica structure leads to an increase in the number of oxygen vacancies in the structure of the MS-Ga system, which can result in an increase in the total and surface oxygen mobility. The results show the highest conversion for benzene (65%), with >40% for toluene and >28% for o-xylene. The high catalytic activity observed was attributed to a combination of several factors including a higher number of active sites (gallium and gallium oxide) being exposed, with a greater mobility of the active oxygen species on the surface of the catalyst promoting the catalytic activity. (author)

  15. Mesoporous metal catalysts formed by ultrasound

    Energy Technology Data Exchange (ETDEWEB)

    Schaeferhans, Jana; Pazos Perez, Nicolas; Andreeva, Daria [Physikalische Chemie II, Universitaet Bayreuth (Germany)

    2010-07-01

    We study the ultrasound-driven formation of mesoporous metal sponges. The collapse of acoustic cavitations leads to very high temperatures and pressures on very short scales. Therefore, structures may be formed and quenched far from equilibrium. Mechanism of metal modification by ultrasound is complex and involves a variety of aspects. We propose that modification of metal particles and formation of mesoporous inner structures can be achieved due to thermal etching of metals by ultrasound stimulated high speed jets of liquid. Simultaneously, oxidation of metal surfaces by free radicals produced in water during cavitation stabilizes developed metal structures. Duration and intensity of the ultrasonication treatment is able to control the structure and morphology of metal sponges. We expect that this approach to the formation of nanoscale composite sponges is universal and opens perspective for a whole new class of catalytic materials that can be prepared in a one-step process. The developed method makes it possible to control the sponge morphology and can be used for formation of modern types of catalysts. For example, the sonication technique allows to combine the fabrication of mesoporous support and distribution of metal (Cu, Pd, Au, Pt etc.) nanoparticles in its pores into a single step.

  16. Translucency and Strength of High Translucency Monolithic Zirconium Oxide Materials

    Science.gov (United States)

    2016-05-17

    Zirconium -Oxide Materials presented at/published to the Journal of General Dentistry with MDWI 41-108, and has been assigned local file #16208. 2...Zirconia-Oxide Materials 6. TITLE OF MATERIAL TO BE PUBLISHED OR PRESENTED: Translucency and Strength of High-Translucency Monolithic Zirconium -Oxide...OBSOLETE 48. DATE Page 3 of 3 Pages Translucency and Strength of High-Translucency Monolithic Zirconium -Oxide Materials Abstract Dental materials

  17. Improvement of the Derjaguin-Broekhoff-de Boer theory for capillary condensation/evaporation of nitrogen in mesoporous systems and its implications for pore size analysis of MCM-41 silicas and related materials.

    Science.gov (United States)

    Kowalczyk, Piotr; Jaroniec, Mietek; Terzyk, Artur P; Kaneko, Katsumi; Do, Duong D

    2005-03-01

    In this work, we propose an improvement of the classical Derjaguin-Broekhoff-de Boer (DBdB) theory for capillary condensation/evaporation in mesoporous systems. The primary idea of this improvement is to employ the Gibbs-Tolman-Koenig-Buff equation to predict the surface tension changes in mesopores. In addition, the statistical film thickness (so-called t-curve) evaluated accurately on the basis of the adsorption isotherms measured for the MCM-41 materials is used instead of the originally proposed t-curve (to take into account the excess of the chemical potential due to the surface forces). It is shown that the aforementioned modifications of the original DBdB theory have significant implications for the pore size analysis of mesoporous solids. To verify our improvement of the DBdB pore size analysis method (IDBdB), a series of the calcined MCM-41 samples, which are well-defined materials with hexagonally ordered cylindrical mesopores, were used for the evaluation of the pore size distributions. The correlation of the IDBdB method with the empirically calibrated Kruk-Jaroniec-Sayari (KJS) relationship is very good in the range of small mesopores. So, a major advantage of the IDBdB method is its applicability for small mesopores as well as for the mesopore range beyond that established by the KJS calibration, i.e., for mesopore radii greater than approximately 4.5 nm. The comparison of the IDBdB results with experimental data reported by Kruk and Jaroniec for capillary condensation/evaporation as well as with the results from nonlocal density functional theory developed by Neimark et al. clearly justifies our approach. Note that the proposed improvement of the classical DBdB method preserves its original simplicity and simultaneously ensures a significant improvement of the pore size analysis, which is confirmed by the independent estimation of the mean pore size by the powder X-ray diffraction method.

  18. 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.

  19. 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.

  20. Characterization of mesoporous VOx/MCM-41 composite materials obtained via post-synthesis impregnation

    International Nuclear Information System (INIS)

    Bukallah, Saeed B.; Bumajdad, Ali; Khalil, Kamal M.S.; Zaki, Mohamed I.

    2010-01-01

    Spherical-particle MCM-41 was synthesized at room temperature, and, then, impregnated with aqueous solutions of NH 4 VO 3 to produce variously loaded VO x /MCM-41 composite materials. Bulk and surface properties of the materials thus produced were characterized by means of X-ray powder diffractometry (XRD), infrared spectroscopy (FTIR), N 2 sorptiometry and X-ray photoelectron spectroscopy (XPS). Results obtained indicated that subsequent calcination at 550 deg. C (for 2 h) of the blank and impregnated MCM-41 particles, results in materials assuming the same bulk structure of MCM-41, and exposing uniformly mesporous, high area surfaces (P w = 2.0-2.3 nm; 974-829 m 2 /g), except for the material obtained at 20 wt%-V 2 O 5 that was shown to suffer a considerable loss on surface area (down to 503 m 2 /g). XPS results implied that the immobilization of the VO x species occurs via interaction with surface OH/H 2 O groups of MCM-41, leading to the formation of vanadate (VO 3 - ) surface species, as well as minor V-O-Si and V 2 O 5 -like species. However, in all cases, the vanadium sites remained pentavalent and exposed on the surface.

  1. Ternary Hollow Mesoporous TiN/N-Graphene/Pt Hybrid Results in Enhanced Electrocatalytic Performance for Methanol Oxidation and Oxygen Reduction Reaction

    International Nuclear Information System (INIS)

    Liu, Baocang; Huo, Lili; Zhang, Geng; Zhang, Jun

    2016-01-01

    Highlights: • A novel hollow mesoporous ternary @M-TiN/N-G/Pt electrocatalysts were synthesized. • The @M-TiN/N-G/Pt electrocatalysts displayed outstanding activity and stability toward MOR and ORR. • The activity and stability of @M-TiN/N-G/Pt electrocatalysts were higher than Pt/TiN, @M-TiN/Pt, and Pt/C catalysts. • The excellent electrocatalytic performance rooted in its unique configuration. • Several reasons were proposed to explain the enhanced electrocatalytic performance of @M-TiN/N-G/Pt. - Abstract: A novel hollow mesoporous TiN/N-graphene (N-G) hybrid architecture (@M-TiN/N-G) composed of N-doped graphene wrapped mesoporous TiN nanoparticle shells was constructed for the first time. It can be used as an efficient support for creating a highly efficient ternary @M-TiN/N-G/Pt electrocatalyst with superior catalytic activity and stability for methanol oxidation reaction (MOR) and oxygen reduction reaction (ORR) through decorating well-dispersed Pt nanoparticles on @M-TiN/N-G surface. By optimizing the content of N-G in catalysts, the @M-TiN/N-G/Pt catalysts display superior catalytic activity and stability toward MOR and ORR to traditional Pt/C and graphene-free Pt/TiN and @M-TiN/Pt catalysts. The various characterization results reveal that the outstanding electrocatalytic performance of @M-TiN/N-G/Pt catalyst roots in its large surface area, high porosity, strong interaction among Pt, TiN, and N-G, excellent electron transfer property facilitated by N-doped graphene, and small size of Pt and TiN nanocrystals. The synthetic approach may be available for constructing other graphene based hollow metal nitrides, carbides, and phosphides for various electrocatalytic applications.

  2. A multi-controlled drug delivery system based on magnetic mesoporous Fe3O4 nanopaticles and a phase change material for cancer thermo-chemotherapy

    Science.gov (United States)

    Zhang, Qi; Liu, Jian; Yuan, Kunjie; Zhang, Zhengguo; Zhang, Xiaowen; Fang, Xiaoming

    2017-10-01

    Herein a novel multi-controlled drug release system for doxorubicin (DOX) was developed, in which monodisperse mesoporous Fe3O4 nanoparticles were combined with a phase change material (PCM) and polyethylene glycol 2000 (PEG2000). It is found that the PCM/PEG/DOX mixture containing 20% PEG could be dissolved into water at 42 °C. The mesoporous Fe3O4 nanoparticles prepared by the solvothermal method had sizes of around 25 nm and exhibited a mesoporous microstructure. A simple solvent evaporation process was employed to load the PCM/PEG/DOX mixture on the mesoporous Fe3O4 nanoparticles completely. In the Fe3O4@PCM/PEG/DOX system, the pores of the Fe3O4 nanoparticles were observed to be filled with the mixture of PCM/PEG/DOX. The Fe3O4@PCM/PEG/DOX system showed a saturation magnetization value of 50.0 emu g-1, lower than 71.1 emu g-1 of the mesoporous Fe3O4 nanoparticles, but it was still high enough for magnetic targeting and hyperthermia application. The evaluation on drug release performance indicated that the Fe3O4@PCM/PEG/DOX system achieved nearly zero release of DOX in vitro in body temperature, while around 80% of DOX could be released within 1.5 h at the therapeutic threshold of 42 °C or under the NIR laser irradiation for about 4 h. And a very rapid release of DOX was achieved by this system when applying an alternating magnetic field. By comparing the systems with and without PEG2000, it is revealed that the presence of PEG2000 makes DOX easy to be released from 1-tetradecanol to water, owing to its functions of increasing the solubility of DOX in 1-tetradecanol as well as decreasing the surface tension between water and 1-tetradecanol. The novel drug release system shows great potential for the development of thermo-chemotherapy of cancer treatment.

  3. Transparent semiconducting oxides: materials and devices

    Energy Technology Data Exchange (ETDEWEB)

    Grundmann, Marius; Frenzel, Heiko; Lajn, Alexander; Lorenz, Michael; Schein, Friedrich; von Wenckstern, Holger [Universitaet Leipzig, Institut fuer Experimentelle Physik II, Linnestr. 5, 04103 Leipzig (Germany)

    2010-06-15

    Transparent conductive oxides (TCOs) are a well-known material class allowing Ohmic conduction. A large free carrier concentration in the 10{sup 21} cm{sup -3} range and high conductivity (beyond 10{sup 4} S/cm) is feasible simultaneously with high transparency. Applications are manifold and include touch screens and front contacts for displays or solar cells. Transparent semiconducting oxides (TSO) are oxides with an intermediate free carrier concentration (typically 10{sup 14}-10{sup 18} cm{sup -3}) allowing the formation of depletion layers. We review recent results on TSO-based transistors and inverters. Most work has been reported on MISFETs. We show that MESFETs exhibit high performance and low voltage operation of oxide electronics. MESFET-based inverters offer superior performance compared to results reported for TSO MISFET-based circuits. Optical image of inverter based on thin film MESFETs with Mg{sub 0.003}Zn{sub 0.997}O channels (left) and experimental inverter characteristic for supply voltage of V{sub DD} = + 2.0 V (right). (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  4. 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

    -to-synthesize mesoporous metal oxides, such as magnesium oxide. We believe that the fundamentals in this research will provide new insights for rational synthesis of ordered mesoporous materials.

  5. Ionic Liquid Directed Mesoporous Carbon Nanoflakes as an Effiencient Electrode material

    Science.gov (United States)

    Kong, Lirong; Chen, Wei

    2015-12-01

    Supercapacitors are considered to be the most promising approach to meet the pressing requirements for energy storage devices. The electrode materials for supercapacitors have close relationship with their electrochemical properties and thus become the key point to improve their energy storage efficiency. Herein, by using poly (vinylidene fluoride-co-hexafluoropropylene) and ionic liquid as the dual templates, polyacrylonitrile as the carbon precursor, a flake-like carbon material was prepared by a direct carbonization method. In this method, poly (vinylidene fluoride-co-hexafluoropropylene) worked as the separator for the formation of isolated carbon flakes while aggregated ionic liquid worked as the pore template. The obtained carbon flakes exhibited a specific capacitance of 170 F/g at 0.1 A/g, a high energy density of 12.2 Wh/kg and a high power density of 5 kW/kg at the current of 10 A/g. It also maintained a high capacitance retention capability with almost no declination after 500 charge-discharge cycles. The ionic liquid directed method developed here also provided a new idea for the preparation of hierarchically porous carbon nanomaterials.

  6. Stability of solid oxide fuel cell materials

    Energy Technology Data Exchange (ETDEWEB)

    Armstrong, T.R.; Bates, J.L.; Coffey, G.W.; Pederson, L.R. [Pacific Northwest National Lab., Richland, WA (United States)] [and others

    1996-08-01

    Chromite interconnection materials in an SOFC are exposed to both highly oxidizing conditions at the cathode and to highly reducing conditions at the anode. Because such conditions could lead to component failure, the authors have evaluated thermal, electrical, chemical, and structural stabilities of these materials as a function of temperature and oxygen partial pressure. The crystal lattice of the chromites was shown to expand for oxygen partial pressures smaller than 10{sup {minus}10} atm, which could lead to cracking and debonding in an SOFC. Highly substituted lanthanum chromite compositions were the most susceptible to lattice expansion; yttrium chromites showed better dimensional stability by more than a factor of two. New chromite compositions were developed that showed little tendency for lattice expansion under strongly reducing conditions, yet provided a good thermal expansion match to other fuel cell components. Use of these new chromite interconnect compositions should improve long-term SOFC performance, particularly for planar cell configurations. Thermodynamic properties of substituted lanthanum manganite cathode compositions have been determined through measurement of electromotive force as a function of temperature. Critical oxygen decomposition pressures for Sr and Ca-substituted lanthanum manganites were established using cells based on a zirconia electrolyte. Strontium oxide and calcium oxide activities in a lanthanum manganite matrix were determined using cells based on strontium fluoride and calcium fluoride electrolytes, respectively. The compositional range of single-phase behavior of these ABO{sub 3}-type perovskites was established as a function of A/B cation ratios and the extent of acceptor doping. Before this work, very little thermodynamic information was in existence for substituted manganite compositions. Such information is needed to predict the long-term stability of solid oxide fuel cell assemblies.

  7. UTILIZATION OF RICE HUSK AS RAW MATERIAL IN SYNTHESIS OF MESOPOROUS SILICATES MCM-41

    Directory of Open Access Journals (Sweden)

    Suyanta Suyanta

    2011-12-01

    Full Text Available The research about synthesis and characterization of MCM-41 from rice husk has been done. Silica (SiO2 was extracted from rice husk by refluxing with 3M hydrochloric solution at 80 °C for 3 h. The acid-leached rice husk was filtered, washed, dried and calcined at 650 °C for 6 h lead the rough powder of rice husk silica with light brown in color. Characterization was carried out by X-ray diffraction (XRD and FTIR spectroscopy method. Rice husk silica was dissolved into the sodium hydroxide solution leading to the solution of sodium silicate, and used as silica source for the synthesis of MCM-41. MCM-41 was synthesized by hydrothermal process to the mixture prepared from 29 g of distilled water, 8.67 g of cetyltrimethyl ammonium bromide (CTMAB, 9.31 g of sodium silicate solution, and amount mL of 1 M H2SO4. Hydrothermal process was carried out at 100 °C in a teflon-lined stainless steel autoclave heated in the oven for 36 h. The solid phase was filtered, then washed with deionised water, and dried in the oven at 100 °C for 2 h. The surfactant CTMAB was removed by calcination at 550 °C for 10 h with heating rate 2 °C/min. The as-synthesized and calcined crystals were characterized by using FTIR spectroscopy, X-ray diffraction and N2 physisorption methods. In order to investigate the effect of silica source, the same procedure was carried out by using pure sodium silicate as silica source. It was concluded that silica extracted from rice husk can be used as raw materials in the synthesis of MCM-41, there is no significant difference in crystallinity and pore properties when was compared to material produced from commercial sodium silicate.

  8. Iodinated oil-loaded, fluorescent mesoporous silica-coated iron oxide nanoparticles for magnetic resonance imaging/computed tomography/fluorescence trimodal imaging

    Directory of Open Access Journals (Sweden)

    Xue S

    2014-05-01

    Full Text Available Sihan Xue,1 Yao Wang,1 Mengxing Wang,2 Lu Zhang,1 Xiaoxia Du,2 Hongchen Gu,1 Chunfu Zhang1,31School of Biomedical Engineering and Med-X Research Institute, Shanghai Jiao Tong University, 2Shanghai Key Laboratory of Magnetic Resonance, Department of Physics, East China Normal University, 3State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, People’s Republic of ChinaAbstract: In this study, a novel magnetic resonance imaging (MRI/computed tomography (CT/fluorescence trifunctional probe was prepared by loading iodinated oil into fluorescent mesoporous silica-coated superparamagnetic iron oxide nanoparticles (i-fmSiO4@SPIONs. Fluorescent mesoporous silica-coated superparamagnetic iron oxide nanoparticles (fmSiO4@SPIONs were prepared by growing fluorescent dye-doped silica onto superparamagnetic iron oxide nanoparticles (SPIONs directed by a cetyltrimethylammonium bromide template. As prepared, fmSiO4@SPIONs had a uniform size, a large surface area, and a large pore volume, which demonstrated high efficiency for iodinated oil loading. Iodinated oil loading did not change the sizes of fmSiO4@SPIONs, but they reduced the MRI T2 relaxivity (r2 markedly. I-fmSiO4@SPIONs were stable in their physical condition and did not demonstrate cytotoxic effects under the conditions investigated. In vitro studies indicated that the contrast enhancement of MRI and CT, and the fluorescence signal intensity of i-fmSiO4@SPION aqueous suspensions and macrophages, were intensified with increased i-fmSiO4@SPION concentrations in suspension and cell culture media. Moreover, for the in vivo study, the accumulation of i-fmSiO4@SPIONs in the liver could also be detected by MRI, CT, and fluorescence imaging. Our study demonstrated that i-fmSiO4@SPIONs had great potential for MRI/C/fluorescence trimodal imaging.Keywords: multifunctional probe, SPIONs, mesoporous silica

  9. Preparation of silica-sustained electrospun polyvinylpyrrolidone fibers with uniform mesopores via oxidative removal of template molecules by H2O2 treatment

    International Nuclear Information System (INIS)

    Kang, Haigang; Zhu, Yihua; Shen, Jianhua; Yang, Xiaoling; Chen, Cheng; Cao, Huimin; Li, Chungzhong

    2010-01-01

    Silica-sustained electrospun PVP fibers with uniform mesopores were synthesized via facile oxidative removal of template molecules by H 2 O 2 extraction. Tetraethyl orthosilicate, polyvinylpyrrolidone (PVP), and triblock poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide) copolymer pluronic P 123 compose the electrospinning sol to fabricate the silica-sustained PVP hybrid fibers. The effect of different post-treatment methods on the pore size distribution was investigated by calcination and extraction, respectively. Experimental results showed that oxidative removal of structure-directing agent P 123 in the hybrid fibers by H 2 O 2 treatment can easily form narrow pore size distribution, and the incorporation of 3D silica skeleton built by hot steam aging facilitated preserving the original cylindrical morphology of fibers. Scanning electron microscopy (SEM), N 2 adsorption-desorption isotherm, transmission electron microscopy (TEM), X-ray diffraction (XRD), FT-IR spectra and thermogravimetric analysis (TGA) were used to characterize the hybrid fibers. The hybrid fibers can be expected to have potential applications in drug release or tissue engineering because of their suitable pore size, large surface area and good biocompatibility.

  10. Novel sponge-like molecularly imprinted mesoporous silica material for selective isolation of bisphenol A and its analogues from sediment extracts

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Jiajia [Key Laboratory of Separation Sciences for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Li, Yun; Wang, Jincheng [Key Laboratory of Separation Sciences for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023 (China); Sun, Xiaoli [Key Laboratory of Separation Sciences for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Shah, Syed Mazhar [Key Laboratory of Separation Sciences for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023 (China); Cao, Rong [Key Laboratory of Separation Sciences for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Chen, Jiping, E-mail: chenjp@dicp.ac.cn [Key Laboratory of Separation Sciences for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023 (China)

    2015-01-01

    Highlights: • Novel sponge-like molecularly imprinted mesoporous silica was synthesized. • Extraordinarily large specific surface area and highly interconnected 3-D porous network. • High specific adsorption capacity and fast adsorption kinetics for BPA. • Good class-selectivity and clean-up effect for bisphenols in sediment under SPE mode. • Good recoveries and sensitivity for bisphenols using the MISMS–SPE coupled with HPLC–DAD method. - Abstract: Bisphenol A (BPA) imprinted sponge mesoporous silica was synthesized using a combination of semi-covalent molecular imprinting and simple self-assembly process. The molecularly imprinted sponge mesoporous silica (MISMS) material obtained was characterized by FT-IR, scanning electron microscopy, transmission electron microscopy, and nitrogen adsorption–desorption measurements. The results show that the MISMS possessed a large specific surface area (850.55 m{sup 2} g{sup −1}) and a highly interconnected 3-D porous network. As a result, the MISMS demonstrated a superior specific adsorption capacity of 169.22 μmol g{sup −1} and fast adsorption kinetics (reaching equilibrium within 3 min) for BPA. Good class selectivity for BPA and its analogues (bisphenol F, bisphenol B, bisphenol E and bisphenol AF) was also demonstrated by the sorption experiment. The MISMS as solid-phase extraction (SPE) material was then evaluated for isolation and clean-up of these bisphenols (BPs) from sediment samples. An accurate and sensitive analytical method based on the MISMS–SPE coupled with HPLC–DAD has been successfully established for simultaneous determination of five BPs in river sediments with detection limits of 0.43–0.71 ng g{sup −1} dry weight (dw). The recoveries of BPs for lyophilizated sediment samples at two spiking levels (50 and 500 ng g{sup −1} dw for each BP) were in the range of 75.5–105.5% with RSD values below 7.5%.

  11. Novel sponge-like molecularly imprinted mesoporous silica material for selective isolation of bisphenol A and its analogues from sediment extracts

    International Nuclear Information System (INIS)

    Yang, Jiajia; Li, Yun; Wang, Jincheng; Sun, Xiaoli; Shah, Syed Mazhar; Cao, Rong; Chen, Jiping

    2015-01-01

    Highlights: • Novel sponge-like molecularly imprinted mesoporous silica was synthesized. • Extraordinarily large specific surface area and highly interconnected 3-D porous network. • High specific adsorption capacity and fast adsorption kinetics for BPA. • Good class-selectivity and clean-up effect for bisphenols in sediment under SPE mode. • Good recoveries and sensitivity for bisphenols using the MISMS–SPE coupled with HPLC–DAD method. - Abstract: Bisphenol A (BPA) imprinted sponge mesoporous silica was synthesized using a combination of semi-covalent molecular imprinting and simple self-assembly process. The molecularly imprinted sponge mesoporous silica (MISMS) material obtained was characterized by FT-IR, scanning electron microscopy, transmission electron microscopy, and nitrogen adsorption–desorption measurements. The results show that the MISMS possessed a large specific surface area (850.55 m 2 g −1 ) and a highly interconnected 3-D porous network. As a result, the MISMS demonstrated a superior specific adsorption capacity of 169.22 μmol g −1 and fast adsorption kinetics (reaching equilibrium within 3 min) for BPA. Good class selectivity for BPA and its analogues (bisphenol F, bisphenol B, bisphenol E and bisphenol AF) was also demonstrated by the sorption experiment. The MISMS as solid-phase extraction (SPE) material was then evaluated for isolation and clean-up of these bisphenols (BPs) from sediment samples. An accurate and sensitive analytical method based on the MISMS–SPE coupled with HPLC–DAD has been successfully established for simultaneous determination of five BPs in river sediments with detection limits of 0.43–0.71 ng g −1 dry weight (dw). The recoveries of BPs for lyophilizated sediment samples at two spiking levels (50 and 500 ng g −1 dw for each BP) were in the range of 75.5–105.5% with RSD values below 7.5%

  12. A green strategy for lithium isotopes separation by using mesoporous silica materials doped with ionic liquids and benzo-15-crown-5

    International Nuclear Information System (INIS)

    Wen Zhou; Xiao-Li Sun; Lin Gu; Fei-Fei Bao; Xin-Xin Xu; Chun-Yan Pang; Zaijun Li; Zhi-Guo Gu; Jiangnan University, Wuxi

    2014-01-01

    Three new mesoporous silica materials IL15SGs (HF15SG, TF15SG and DF15SG) doped with benzo-15-crown-5 and imidazolium based ionic liquids (C 8 mim + PF 6 - , C 8 mim + BF 4 - or C 8 mim + NTf 2 - ) have been prepared by a simple approach to separating lithium isotopes. The formed mesoporous structures of silica gels have been confirmed by transmission electron microscopy image and N 2 gas adsorption-desorption isotherm. Imidazolium ionic liquids acted as templates to prepare mesoporous materials, additives to stabilize extractant within silica gel, and synergetic agents to separate the lithium isotopes. Factors such as lithium salt concentration, initial pH, counter anion of lithium salt, extraction time, and temperature on the lithium isotopes separation were examined. Under optimized conditions, the extraction efficiency of HF15SG, TF15SG and DF15SG were found to be 11.43, 10.59 and 13.07 %, respectively. The heavier isotope 7 Li was concentrated in the solution phase while the lighter isotope 6 Li was enriched in the gel phase. The solid-liquid extraction maximum single-stage isotopes separation factor of 6 Li- 7 Li in the solid-liquid extraction was up to 1.046 ± 0.002. X-ray crystal structure analysis indicated that the lithium salt was extracted into the solid phase with crown ether forming [(Li 0.5 ) 2 (B 15 ) 2 (H 2 O)] + complexes. IL15SGs were also easily regenerated by stripping with 20 mmol L -1 HCl and reused in the consecutive removal of lithium ion in five cycles. (author)

  13. Synthesis of Hierarchically Structured Hybrid Materials by Controlled Self-Assembly of Metal-Organic Framework with Mesoporous Silica for CO2 Adsorption.

    Science.gov (United States)

    Chen, Chong; Li, Bingxue; Zhou, Lijin; Xia, Zefeng; Feng, Nengjie; Ding, Jing; Wang, Lei; Wan, Hui; Guan, Guofeng

    2017-07-12

    The HKUST-1@SBA-15 composites with hierarchical pore structure were constructed by in situ self-assembly of metal-organic framework (MOF) with mesoporous silica. The structure directing role of SBA-15 had an obvious impact on the growth of MOF crystals, which in turn affected the morphologies and structural properties of the composites. The pristine HKUST-1 and the composites with different content of SBA-15 were characterized by XRD, N 2 adsorption-desorption, SEM, TEM, FT-IR, TG, XPS, and CO 2 -TPD techniques. It was found that the composites were assembled by oriented growth of MOF nanocrystals on the surfaces of SBA-15 matrix. The interactions between surface silanol groups and metal centers induced structural changes and resulted in the increases in surface areas as well as micropore volumes of hybrid materials. Besides, the additional constraints from SBA-15 also restrained the expansion of HKUST-1, contributing to their smaller crystal sizes in the composites. The adsorption isotherms of CO 2 on the materials were measured and applied to calculate the isosteric heats of adsorption. The HS-1 composite exhibited an increase of 15.9% in CO 2 uptake capacity compared with that of HKUST-1. Moreover, its higher isosteric heats of CO 2 adsorption indicated the stronger interactions between the surfaces and CO 2 molecules. The adsorption rate of the composite was also improved due to the introduction of mesopores. Ten cycles of CO 2 adsorption-desorption experiments implied that the HS-1 had excellent reversibility of CO 2 adsorption. This study was intended to provide the possibility of assembling new composites with tailored properties based on MOF and mesoporous silica to satisfy the requirements of various applications.

  14. 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).

  15. 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.

  16. Dynamic mean field theory for lattice gas models of fluid mixtures confined in mesoporous materials.

    Science.gov (United States)

    Edison, J R; Monson, P A

    2013-11-12

    We present the extension of dynamic mean field theory (DMFT) for fluids in porous materials (Monson, P. A. J. Chem. Phys. 2008, 128, 084701) to the case of mixtures. The theory can be used to describe the relaxation processes in the approach to equilibrium or metastable equilibrium states for fluids in pores after a change in the bulk pressure or composition. It is especially useful for studying systems where there are capillary condensation or evaporation transitions. Nucleation processes associated with these transitions are emergent features of the theory and can be visualized via the time dependence of the density distribution and composition distribution in the system. For mixtures an important component of the dynamics is relaxation of the composition distribution in the system, especially in the neighborhood of vapor-liquid interfaces. We consider two different types of mixtures, modeling hydrocarbon adsorption in carbon-like slit pores. We first present results on bulk phase equilibria of the mixtures and then the equilibrium (stable/metastable) behavior of these mixtures in a finite slit pore and an inkbottle pore. We then use DMFT to describe the evolution of the density and composition in the pore in the approach to equilibrium after changing the state of the bulk fluid via composition or pressure changes.

  17. Block copolymer self-assembly–directed synthesis of mesoporous gyroidal superconductors

    Science.gov (United States)

    Robbins, Spencer W.; Beaucage, Peter A.; Sai, Hiroaki; Tan, Kwan Wee; Werner, Jörg G.; Sethna, James P.; DiSalvo, Francis J.; Gruner, Sol M.; Van Dover, Robert B.; Wiesner, Ulrich

    2016-01-01

    Superconductors with periodically ordered mesoporous structures are expected to have properties very different from those of their bulk counterparts. Systematic studies of such phenomena to date are sparse, however, because of a lack of versatile synthetic approaches to such materials. We demonstrate the formation of three-dimensionally continuous gyroidal mesoporous niobium nitride (NbN) superconductors from chiral ABC triblock terpolymer self-assembly–directed sol-gel–derived niobium oxide with subsequent thermal processing in air and ammonia gas. Superconducting materials exhibit a critical temperature (Tc) of about 7 to 8 K, a flux exclusion of about 5% compared to a dense NbN solid, and an estimated critical current density (Jc) of 440 A cm−2 at 100 Oe and 2.5 K. We expect block copolymer self-assembly–directed mesoporous superconductors to provide interesting subjects for mesostructure-superconductivity correlation studies. PMID:27152327

  18. Block copolymer self-assembly-directed synthesis of mesoporous gyroidal superconductors.

    Science.gov (United States)

    Robbins, Spencer W; Beaucage, Peter A; Sai, Hiroaki; Tan, Kwan Wee; Werner, Jörg G; Sethna, James P; DiSalvo, Francis J; Gruner, Sol M; Van Dover, Robert B; Wiesner, Ulrich

    2016-01-01

    Superconductors with periodically ordered mesoporous structures are expected to have properties very different from those of their bulk counterparts. Systematic studies of such phenomena to date are sparse, however, because of a lack of versatile synthetic approaches to such materials. We demonstrate the formation of three-dimensionally continuous gyroidal mesoporous niobium nitride (NbN) superconductors from chiral ABC triblock terpolymer self-assembly-directed sol-gel-derived niobium oxide with subsequent thermal processing in air and ammonia gas. Superconducting materials exhibit a critical temperature (T c) of about 7 to 8 K, a flux exclusion of about 5% compared to a dense NbN solid, and an estimated critical current density (J c) of 440 A cm(-2) at 100 Oe and 2.5 K. We expect block copolymer self-assembly-directed mesoporous superconductors to provide interesting subjects for mesostructure-superconductivity correlation studies.

  19. Core/shell magnetic mesoporous silica nanoparticles with radially oriented wide mesopores

    Directory of Open Access Journals (Sweden)

    Nikola Ž. Knežević

    2014-06-01

    Full Text Available Core/shell nanoparticles, containing magnetic iron-oxide (maghemite core and mesoporous shell with radial porous structure, were prepared by dispersing magnetite nanoparticles and adding tetraethylorthosilicate to a basic aqueous solution containing structure-templating cetyltrimethylammonium bromide and a pore-swelling mesithylene. The material is characterized by SEM and TEM imaging, nitrogen sorption and powder X-ray diffraction. Distinctive features of the prepared material are its high surface area (959 m2/g, wide average pore diameter (12.4 nm and large pore volume (2.3 cm3/g. The material exhibits radial pore structure and the high angle XRD pattern characteristic for maghemite nanoparticles, which are obtained upon calcination of the magnetite-containing material. The observed properties of the prepared material may render the material applicable in separation, drug delivery, sensing and heterogeneous catalysis.

  20. Synthesis and characterization of triflic acid-functionalized mesoporous Zr-TMS catalysts: heterogenization of CF3SO3H over Zr-TMS and its catalytic activity

    NARCIS (Netherlands)

    Chidambaram, M.; Curulla Ferre, D.; Singh, A.P.; Anderson, B.G.

    2003-01-01

    Triflic acid-functionalized Zr-TMS (zirconium oxide with a mesostructured framework; TMS, transition metal oxide mesoporous molecular sieves) catalysts have been synthesized by functionalizing triflic acid onto the walls of Zr-TMS via post synthesis method. The synthesized materials were

  1. Research Update: Mesoporous sensor nanoarchitectonics

    Directory of Open Access Journals (Sweden)

    Katsuhiko Ariga

    2014-03-01

    Full Text Available In this short review, we have selected three main subjects: (i mesoporous materials, (ii sensing applications, and (iii the concept of nanoarchitectonics, as examples of recent hot topics in nanomaterials research. Mesoporous materials satisfy the conditions necessary not only for a wide range of applications but also for ease of production, by a variety of simple processes, which yield bulk quantities of materials without loss of their well-defined nanometric structural features. Sensing applications are of general importance because many events arise from interaction with external stimuli. In addition to these important features, nanoarchitectonics is a concept aimed at production of novel functionality of whole units according to concerted interactions within nanostructures. For the combined subject of mesoporous sensor nanoarchitectonics, we present recent examples of research in the corresponding fields categorized according to mechanism of detection including optical, electrical, and piezoelectric sensing.

  2. One-step synthesis of mesoporous silica–graphene composites by ...

    Indian Academy of Sciences (India)

    Silica–graphene oxide composites were synthesized by hydrothermal method with simultaneous functionalization and reduction of graphene oxide (GO) in the presence of mesoporous silica. Two types of silica were used in the study, mesoporous synthetic silica (MSU-F) synthesized by sol-gel method and mesoporous ...

  3. A green surfactant-assisted synthesis of hierarchical TS-1 zeolites with excellent catalytic properties for oxidative desulfurization.

    Science.gov (United States)

    Du, Shuting; Li, Fen; Sun, Qiming; Wang, Ning; Jia, Mingjun; Yu, Jihong

    2016-02-25

    Hierarchical TS-1 zeolites with uniform intracrystalline mesopores have been successfully synthesized through the hydrothermal method by using the green and cheap surfactant Triton X-100 as the mesoporous template. The resultant materials exhibit remarkably enhanced catalytic activity in oxidative desulfurization reactions compared to the conventional TS-1 zeolite.

  4. Unprecedented Selective Oxidation of Styrene Derivatives using a Supported Iron Oxide Nanocatalyst in Aqueous Medium

    Science.gov (United States)

    Iron oxide nanoparticles supported on mesoporous silica-type materials have been successfully utilized in the aqueous selective oxidation of alkenes under mild conditions using hydrogen peroxide as a green oxidant. Catalysts could be easily recovered after completion of the reac...

  5. Synthesis of mesoporous Cr/ZSM-5 and W-Cr/ZSM-5 zeolite catalysts for oxidation of unsaturated fatty acid

    Directory of Open Access Journals (Sweden)

    Phan Huy Hoang

    2017-10-01

    Full Text Available The mesoporous Cr/ZSM-5 and W-Cr/ZSM-5 zeolites have been successfully synthesized by loading chromium and tungsten on zeolite support. The metal loaded ZSM-5 catalysts were analyzed by several characterizations such as XRD, SEM-EDS, TEM, and BET. The catalytic activities and recycle efficiency were also investigated by applying catalysts for oxidation of oleic acid. These catalysts exhibited the high catalytic efficiency for cleavage of double bond with the use of H2O2. The oleic conversion of 88.7% and 93.3% could be achieved for Cr/ZSM-5 and W-Cr/ZSM-5 catalyst, respectively. Moreover, the modified ZSM-5 catalysts also demonstrated a long life time and high stability.

  6. Synthesis Mechanism and Thermal Optimization of an Economical Mesoporous Material Using Silica: Implications for the Effective Removal or Delivery of Ibuprofen.

    Directory of Open Access Journals (Sweden)

    Shanmuga Kittappa

    Full Text Available Mesoporous silica materials (MSMs were synthesized economically using silica (SiO2 as a precursor via a modified alkaline fusion method. The MSM prepared at 500°C (MSM-500 had the highest surface area, pore size, and volume, and the results of isotherms and the kinetics of ibuprofen (IBP removal indicated that MSM-500 had the highest sorption capacity and fastest removal speed vs. SBA-15 and zeolite. Compared with commercial granular activated carbon (GAC, MSM-500 had a ~100 times higher sorption rate at neutral pH. IBP uptake by MSM-500 was thermodynamically favorable at room temperature, which was interpreted as indicating relatively weak bonding because the entropy (∆adsS, -0.07 J mol(-1 K(-1 was much smaller. Five times recycling tests revealed that MSM-500 had 83-87% recovery efficiencies and slower uptake speeds due to slight deformation of the outer pore structure. In the IBP delivery test, MSM-500 drug loading was 41%, higher than the reported value of SBA-15 (31%. The in vitro release of IBP was faster, almost 100%, reaching equilibrium within a few hours, indicating its effective loading and unloading characteristics. A cost analysis study revealed that the MSM was ~10-70 times cheaper than any other mesoporous silica material for the removal or delivery of IBP.

  7. Mesoporous NiCo2O4 nanoneedles grown on 3D graphene-nickel foam for supercapacitor and methanol electro-oxidation

    International Nuclear Information System (INIS)

    Yu, Mei; Chen, Jianpeng; Liu, Jianhua; Li, Songmei; Ma, Yuxiao; Zhang, Jingdan; An, Junwei

    2015-01-01

    Mesoporous NiCo 2 O 4 nanoneedles were directly grown on three dimensional (3D) graphene-nickel foam which was prepared by chemical vapor deposition, labeled as NCO/GNF. The structure and morphology of NCO/GNF were investigated by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, element mapping and Raman spectroscopy. The NCO/GNF was employed as electrodes for supercapacitor and methanol electro-oxidation. When used for supercapacitor, the NiCo 2 O 4 nanoneedles exhibit hi exhibit high specific capacitance (1588 F g −1 at 1 A g −1 ), high power density and energy density (33.88 Wh kg −1 at 5 kW kg −1 ) as well as long cycling stability. In methanol electro-oxidation, the NiCo 2 O 4 nanoneedles deliver high electro-oxidation activity (93.3 A g −1 at 0.65 V) and electro-oxidation stability. The good electrochemical performance of NiCo 2 O 4 nanoneedles is attributed to the 3D structure with large specific area, high conductivity and fast ions/electrons transport

  8. Ti2Nb10O29-x mesoporous microspheres as promising anode materials for high-performance lithium-ion batteries

    Science.gov (United States)

    Deng, Shengjue; Luo, Zhibin; Liu, Yating; Lou, Xiaoming; Lin, Chunfu; Yang, Chao; Zhao, Hua; Zheng, Peng; Sun, Zhongliang; Li, Jianbao; Wang, Ning; Wu, Hui

    2017-09-01

    Ti2Nb10O29 has recently been reported as a promising anode material for lithium-ion batteries. However, its poor electronic conductivity and insufficient Li+-ion diffusion coefficient significantly limit its rate capability. To tackle this issue, a strategy combining nanosizing and crystal-structure modification is employed. Ti2Nb10O29-x mesoporous microspheres with a sphere-size range of 0.5-4 μm are prepared by a one-step solvothermal method followed by thermal treatment in N2. These Ti2Nb10O29-x mesoporous microspheres exhibit primary nanoparticles, a large specific surface area (22.9 m2 g-1) and suitable pore sizes, leading to easy electron/Li+-ion transport and good interfacial reactivity. Ti2Nb10O29-x shows a defective shear ReO3 crystal structure with O2- vacancies and an increased unit cell volume, resulting in its increased Li+-ion diffusion coefficient. Besides Ti4+ and Nb5+ ions, Ti2Nb10O29-x comprises Nb4+ ions with unpaired 4d electrons, which significantly increase its electronic conductivity. As a result of these improvements, the Ti2Nb10O29-x mesoporous microspheres reveal superior electrochemical performances in term of large reversible specific capacity (309 mAh g-1 at 0.1 C), outstanding rate capability (235 mAh g-1 at 40 C) and durable cyclic stability (capacity retention of 92.1% over 100 cycles at 10 C).

  9. Sealing materials for solid oxide fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Larsen, P.H.

    1999-02-01

    A major obstacle in the achievement of high electrical efficiency for planar solid oxide fuel cell stacks (SOFC) is the need for long term stable seals at the operational temperature between 850 and 1000 deg. C. In the present work the formation and properties of sealing materials for SOFC stacks that fulfil the necessary requirements were investigated. The work comprises analysis of sealing material properties independently, in simple systems as well as tests in real SOFC stacks. The analysed sealing materials were based on pure glasses or glass-ceramic composites having B{sub 2}O{sub 3}, P{sub 2}O{sub 5} or siO{sub 2} as glass formers, and the following four glass systems were investigated: MgO/caO/Cr{sub 2}O{sub 3}-Al{sub 2}O{sub 3}B{sub 2}O{sub 3}-P{sub 2}O{sub 5}, MgO-Al{sub 2}O{sub 3}-P{sub 2}O{sub 5}, MgO-Al{sub 2}O{sub 3}-P{sub 2}O{sub 5}-SiO{sub 2} and BaO/Na{sub 2}O-Al{sub 2}O{sub 3}-SiO{sub 2}. (au) 32 tabs., 106 ills., 107 refs.

  10. Gas Generation from Actinide Oxide Materials

    Energy Technology Data Exchange (ETDEWEB)

    George Bailey; Elizabeth Bluhm; John Lyman; Richard Mason; Mark Paffett; Gary Polansky; G. D. Roberson; Martin Sherman; Kirk Veirs; Laura Worl

    2000-12-01

    This document captures relevant work performed in support of stabilization, packaging, and long term storage of plutonium metals and oxides. It concentrates on the issue of gas generation with specific emphasis on gas pressure and composition. Even more specifically, it summarizes the basis for asserting that materials loaded into a 3013 container according to the requirements of the 3013 Standard (DOE-STD-3013-2000) cannot exceed the container design pressure within the time frames or environmental conditions of either storage or transportation. Presently, materials stabilized and packaged according to the 3013 Standard are to be transported in certified packages (the certification process for the 9975 and the SAFKEG has yet to be completed) that do not rely on the containment capabilities of the 3013 container. Even though no reliance is placed on that container, this document shows that it is highly likely that the containment function will be maintained not only in storage but also during transportation, including hypothetical accident conditions. Further, this document, by summarizing materials-related data on gas generation, can point those involved in preparing Safety Analysis Reports for Packages (SARPs) to additional information needed to assess the ability of the primary containment vessel to contain the contents and any reaction products that might reasonably be produced by the contents.

  11. Gas Generation from Actinide Oxide Materials

    International Nuclear Information System (INIS)

    Bailey, George; Bluhm, Elizabeth; Lyman, John; Mason, Richard; Paffett, Mark; Polansky, Gary; Roberson, G. D.; Sherman, Martin; Veirs, Kirk; Worl, Laura

    2000-01-01

    This document captures relevant work performed in support of stabilization, packaging, and long term storage of plutonium metals and oxides. It concentrates on the issue of gas generation with specific emphasis on gas pressure and composition. Even more specifically, it summarizes the basis for asserting that materials loaded into a 3013 container according to the requirements of the 3013 Standard (DOE-STD-3013-2000) cannot exceed the container design pressure within the time frames or environmental conditions of either storage or transportation. Presently, materials stabilized and packaged according to the 3013 Standard are to be transported in certified packages (the certification process for the 9975 and the SAFKEG has yet to be completed) that do not rely on the containment capabilities of the 3013 container. Even though no reliance is placed on that container, this document shows that it is highly likely that the containment function will be maintained not only in storage but also during transportation, including hypothetical accident conditions. Further, this document, by summarizing materials-related data on gas generation, can point those involved in preparing Safety Analysis Reports for Packages (SARPs) to additional information needed to assess the ability of the primary containment vessel to contain the contents and any reaction products that might reasonably be produced by the contents

  12. Preparation of hollow mesoporous carbon spheres and their performances for electrochemical applications

    Science.gov (United States)

    Ariyanto, T.; Zhang, G. R.; Kern, A.; Etzold, B. J. M.

    2018-03-01

    Hollow carbon materials have received intensive attention for energy storage/conversion applications due to their attractive properties of high conductivity, high surface area, large void and short diffusion pathway. In this work, a novel hollow mesoporous material based on carbide-derived carbon (CDC) is presented. CDC is a new class of carbon material synthesized by the selective extraction of metals from metal carbides. With a two-stage extraction procedure of carbides with chlorine, firstly hybrid core-shell carbon particles were synthesized, i.e. mesoporous/graphitic carbon shells covering microporous/amorphous carbon cores. The amorphous cores were then selectively removed from particles by a careful oxidative treatment utilizing its low thermal characters while the more stable carbon shells remained, thus resulting hollow particles. The characterization methods (e.g. N2 sorption, Raman spectroscopy, temperature-programmed oxidation and SEM) proved the successful synthesis of the aspired material. In electric double-layer capacitor (EDLC) testing, this novel hollow core material showed a remarkable enhancement of EDLC’s rate handling ability (75% at a high scan rate) with respect to an entirely solid-mesoporous material. Furthermore, as a fuel cell catalyst support the material showed higher Pt mass activity (a factor of 1.8) compared to a conventional carbon support for methanol oxidation without noticeably decreasing activity in a long-term testing. Therefore, this carbon nanostructure shows great promises as efficient electrode materials for energy storage and conversion systems.

  13. Sorption analyses in materials science: selected oxides

    International Nuclear Information System (INIS)

    Fuller, E.L. Jr.; Condon, J.B.; Eager, M.H.; Jones, L.L.

    1981-01-01

    Physical adsorption studies have been shown to be extremely valuable in studying the chemistry and structure of dispersed materials. Many processes rely on the access to the large amount of surface made available by the high degree of dispersion. Conversely, there are many applications where consolidation of the dispersed solids is required. Several systems (silica gel, alumina catalysts, mineralogic alumino-silicates, and yttrium oxide plasters) have been studied to show the type and amount of chemical and structural information that can be obtained. Some review of current theories is given and additional concepts are developed based on statistical and thermodynamic arguments. The results are applied to sorption data to show that detailed sorption analyses are extremely useful and can provide valuable information that is difficult to obtain by any other means. Considerable emphasis has been placed on data analyses and interpretation of a nonclassical nature to show the potential of such studies that is often not recognized nor utilized

  14. Direct hydrothermal synthesis of iron-containing mesoporous silica SBA-15 : potential as a support for gold nanoparticles

    NARCIS (Netherlands)

    Li, Y.; Guan, Y.; Santen, van R.A.; Kooyman, P.J.; Dugulan, A.I.; Li, C.; Hensen, E.J.M.

    2009-01-01

    The preparation of mesoporous silica SBA-15 with high iron loadings (14-90 wt % Fe2O3) as a suitable support for gold nanoparticles to be used in CO oxidation catalysis has been investigated. The support materials were prepared by a direct hydrothermal two-step pH adjusting method which consisted of

  15. Preparation of Reduced Graphene Oxides as Electrode Materials for Supercapacitors

    KAUST Repository

    Bai, Yaocai

    2012-01-01

    Reduced graphene oxide as outstanding candidate electrode material for supercapacitor has been investigated. This thesis includes two topics. One is that three kinds of reduced graphene oxides were prepared by hydrothermal reduction under different

  16. Enhanced thermal properties of novel shape-stabilized PEG composite phase change materials with radial mesoporous silica sphere for thermal energy storage.

    Science.gov (United States)

    Min, Xin; Fang, Minghao; Huang, Zhaohui; Liu, Yan'gai; Huang, Yaoting; Wen, Ruilong; Qian, Tingting; Wu, Xiaowen

    2015-08-11

    Radial mesoporous silica (RMS) sphere was tailor-made for further applications in producing shape-stabilized composite phase change materials (ss-CPCMs) through a facile self-assembly process using CTAB as the main template and TEOS as SiO2 precursor. Novel ss-CPCMs composed of polyethylene glycol (PEG) and RMS were prepared through vacuum impregnating method. Various techniques were employed to characterize the structural and thermal properties of the ss-CPCMs. The DSC results indicated that the PEG/RMS ss-CPCM was a promising candidate for building thermal energy storage applications due to its large latent heat, suitable phase change temperature, good thermal reliability, as well as the excellent chemical compatibility and thermal stability. Importantly, the possible formation mechanisms of both RMS sphere and PEG/RMS composite have also been proposed. The results also indicated that the properties of the PEG/RMS ss-CPCMs are influenced by the adsorption limitation of the PEG molecule from RMS sphere with mesoporous structure and the effect of RMS, as the impurities, on the perfect crystallization of PEG.

  17. Mesoporous carbon-zirconium oxide nanocomposite derived from carbonized metal organic framework: A coating for solid-phase microextraction.

    Science.gov (United States)

    Saraji, Mohammad; Mehrafza, Narges

    2016-08-19

    In this paper, a mesoporous carbon-ZrO2 nanocomposite was fabricated on a stainless steel wire for the first time and used as the solid-phase microextraction coating. The fiber was synthesized with the direct carbonization of a Zr-based metal organic framework. With the utilization of the metal organic framework as the precursor, no additional carbon source was used for the synthesis of the mesoporous carbon-ZrO2 nanocomposite coating. The fiber was applied for the determination of BTEX compounds (benzene, toluene, ethylbenzene and m, p-xylenes) in different water samples prior to gas chromatography-flame ionization detection. Such important experimental factors as synthesis time and temperature, salt concentration, equilibrium and extraction time, extraction temperature, desorption time and desorption temperature were studied and optimized. Good linearity in the concentration range of 0.2-200μgL(-1) and detection limits in the range of 0.05-0.56μgL(-1) was achieved for BTEX compounds. The intra- and inter-day relative standard deviations were in the range of 3.5-4.8% and 4.9-6.7%, respectively. The prepared fiber showed high capability for the analysis of BTEX compounds in different water and wastewater samples with good relative recoveries in the range of 93-107%. Copyright © 2016 Elsevier B.V. All rights reserved.

  18. Synthesis of honeycomb-like mesoporous nitrogen-doped carbon nanospheres as Pt catalyst supports for methanol oxidation in alkaline media

    Science.gov (United States)

    Zhang, Yunmao; Liu, Yong; Liu, Weihua; Li, Xiying; Mao, Liqun

    2017-06-01

    This paper reports the convenient synthesis of honeycomb-like mesoporous nitrogen-doped carbon spheres (MNCS) using a self-assembly strategy that employs dopamine (DA) as a carbon and nitrogen precursor and a polystyrene-b-poly(ethylene oxide) (PS173-b-PEO170) diblock copolymer as a soft template. The MNCS have large BET surface areas of up to 554 m2 g-1 and high nitrogen contents of up to 6.9 wt%. The obtained MNCS are used as a support for Pt catalysts, which promote methanol oxidation in alkaline media. The MNCS-supported Pt (Pt/MNCS) catalyst has a larger electrochemically active surface area (ESA) (89.2 m2 g-1) than does a commercially available Vulcan XC-72R supported Pt/C catalyst. Compared to the Pt/C catalyst, Pt/MNCS displays a higher peak current density (1007 mA mg-1) and is more stable during methanol oxidation. These improvements are attributed to the honeycomb-like porous structure of the MNCS and the introduction of nitrogen to the carbon support. The MNCS effectively stabilize Pt nanoparticles and assuage the agglomeration of the nanoparticles, suggesting that MNCS are potential and promising application as electrocatalyst supports in alkaline direct methanol fuel cells.

  19. 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

  20. Carbon dioxide adsorption on micro-mesoporous composite materials of ZSM-12/MCM-48 type: The role of the contents of zeolite and functionalized amine

    International Nuclear Information System (INIS)

    2CEM, São Cristovão/SE (Brazil))" data-affiliation=" (Federal University of Sergipe, Materials Science and Engineering Postgraduate Program P2CEM, São Cristovão/SE (Brazil))" >Santos, S.C.G.; Pedrosa, A.M.Garrido; Souza, M.J.B.; Cecilia, J.A.; Rodríguez-Castellón, E.

    2015-01-01

    Highlights: • Synthesis of the micro-mesoporous composite materials of ZSM-12/MCM-48 type. • Application of these adsorbents in the carbon dioxide adsorption. • Effects of the contents of zeolite and amino group in the material surface on the CO 2 capture efficiency. - Abstract: In this study ZSM-12/MCM-48 adsorbents have been synthesized at three ZSM-12 content, and also were functionalizated with amine groups by grafting. All the adsorbents synthesized were evaluated for CO 2 capture. The X-ray diffraction analysis of the ZSM-12/MCM-48 composite showed the main characteristic peaks of ZSM-12 and MCM-48, and after the functionalization, the structure of MCM-48 on the composite impregnated was affected due amine presence. For the composites without amine, the ZSM-12 content was the factor determining in the adsorption capacity of CO 2 and for the composites with amine the amount of amine was that influenced in the adsorption capacity

  1. Oxide materials for spintronic device applications

    Science.gov (United States)

    Prestgard, Megan Campbell

    Spintronic devices are currently being researched as next-generation alternatives to traditional electronics. Electronics, which utilize the charge-carrying capabilities of electrons to store information, are fundamentally limited not only by size constraints, but also by limits on current flow and degradation, due to electro-migration. Spintronics devices are able to overcome these limitations, as their information storage is in the spin of electrons, rather than their charge. By using spin rather than charge, these current-limiting shortcomings can be easily overcome. However, for spintronic devices to be fully implemented into the current technology industry, their capabilities must be improved. Spintronic device operation relies on the movement and manipulation of spin-polarized electrons, in which there are three main processes that must be optimized in order to maximize device efficiencies. These spin-related processes are: the injection of spin-polarized electrons, the transport and manipulation of these carriers, and the detection of spin-polarized currents. In order to enhance the rate of spin-polarized injection, research has been focused on the use of alternative methods to enhance injection beyond that of a simple ferromagnetic metal/semiconductor injector interface. These alternatives include the use of oxide-based tunnel barriers and the modification of semiconductors and insulators for their use as ferromagnetic injector materials. The transport of spin-polarized carriers is heavily reliant on the optimization of materials' properties in order to enhance the carrier mobility and to quench spin-orbit coupling (SOC). However, a certain degree of SOC is necessary in order to allow for the electric-field, gate-controlled manipulation of spin currents. Spin detection can be performed via both optical and electrical techniques. Using electrical methods relies on the conversion between spin and charge currents via SOC and is often the preferred method for

  2. Efficient luminescent materials based on the incorporation of a Eu(III)tris-(bipyridine-carboxylate) complex in mesoporous hybrid silicate hosts

    Energy Technology Data Exchange (ETDEWEB)

    Botelho, M.B.S. [Instituto de Física de São Carlos, Universidade de São Paulo, 13566-590 São Carlos, SP (Brazil); Universidade de Brasilia, 70910-900 Brasilia, DF (Brazil); Queiroz, T.B. de [Instituto de Física de São Carlos, Universidade de São Paulo, 13566-590 São Carlos, SP (Brazil); Eckert, H. [Instituto de Física de São Carlos, Universidade de São Paulo, 13566-590 São Carlos, SP (Brazil); Institut für Physikalische Chemie, Westfälische Wilhelms Universität Münster, D-48149 Münster (Germany); Camargo, A.S.S. de, E-mail: andreasc@ifsc.usp.br [Instituto de Física de São Carlos, Universidade de São Paulo, 13566-590 São Carlos, SP (Brazil)

    2016-02-15

    The study of the photoluminescent characteristics of host–guest systems based on highly emissive trivalent rare earth complexes such as Eu{sup 3+} – tris-bipyridine-carboxylate, immobilized in solid state host matrices, is motivated by their potential applications in optoelectronic devices and bioanalytical systems. Besides offering the possibility of designing a favorable environment to improve the photophysical properties of the guest molecules, encapsulation in porous solids also serves to protect such molecules, prevents leakage (especially critical for bio-applications) and ultimately leads to more robust and versatile materials. Among the most interesting possible host matrices are mesoporous silica and hybrids (organo-silicates) in the form of powders (MCM-41 like) and transparent bulk or film xerogels. In this work we report the synthesis of highly efficient red emitting materials based on the wet impregnation of such host matrices with the new complex Eu[4-(4′-tert-butyl-biphenyl-4-yl)-2,2′-bipyridine-6-carboxyl]{sub 3} (“[{sup t}Bu–COO]{sub 3}Eu”) whose synthesis and photophysical characterization was recently reported. Prior to the incorporation, the host matrices were thoroughly characterized by solid state {sup 29}Si and {sup 1}H NMR, N{sub 2} adsorption/desorption isotherms, and scanning electron microscopy (SEM). Incorporation and retention of the complex molecules are found to be significantly higher in the phenyl-modified hybrid samples than in the regular mesoporous silica, suggesting efficient immobilization of the complex by π–π interactions. Long excited state lifetimes (up to 1.7 ms comparable to 1.8 ms for the complex in solution), and high quantum yields (up to 65%, versus 85% for the complex in solution) were measured for the bulk xerogel materials, suggesting the potential use of thin films for lighting and bioanalytical applications. - Highlights: • New Eu(III) complex in mesoporous hybrid matrices leads to highly

  3. Efficient luminescent materials based on the incorporation of a Eu(III)tris-(bipyridine-carboxylate) complex in mesoporous hybrid silicate hosts

    International Nuclear Information System (INIS)

    Botelho, M.B.S.; Queiroz, T.B. de; Eckert, H.; Camargo, A.S.S. de

    2016-01-01

    The study of the photoluminescent characteristics of host–guest systems based on highly emissive trivalent rare earth complexes such as Eu 3+ – tris-bipyridine-carboxylate, immobilized in solid state host matrices, is motivated by their potential applications in optoelectronic devices and bioanalytical systems. Besides offering the possibility of designing a favorable environment to improve the photophysical properties of the guest molecules, encapsulation in porous solids also serves to protect such molecules, prevents leakage (especially critical for bio-applications) and ultimately leads to more robust and versatile materials. Among the most interesting possible host matrices are mesoporous silica and hybrids (organo-silicates) in the form of powders (MCM-41 like) and transparent bulk or film xerogels. In this work we report the synthesis of highly efficient red emitting materials based on the wet impregnation of such host matrices with the new complex Eu[4-(4′-tert-butyl-biphenyl-4-yl)-2,2′-bipyridine-6-carboxyl] 3 (“[ t Bu–COO] 3 Eu”) whose synthesis and photophysical characterization was recently reported. Prior to the incorporation, the host matrices were thoroughly characterized by solid state 29 Si and 1 H NMR, N 2 adsorption/desorption isotherms, and scanning electron microscopy (SEM). Incorporation and retention of the complex molecules are found to be significantly higher in the phenyl-modified hybrid samples than in the regular mesoporous silica, suggesting efficient immobilization of the complex by π–π interactions. Long excited state lifetimes (up to 1.7 ms comparable to 1.8 ms for the complex in solution), and high quantum yields (up to 65%, versus 85% for the complex in solution) were measured for the bulk xerogel materials, suggesting the potential use of thin films for lighting and bioanalytical applications. - Highlights: • New Eu(III) complex in mesoporous hybrid matrices leads to highly emissive material • Matrix

  4. 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.

  5. 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.

  6. Innovative oxide materials for electrochemical energy conversion and oxygen separation

    Science.gov (United States)

    Belousov, V. V.

    2017-10-01

    Ion-conducting solid metal oxides are widely used in high-temperature electrochemical devices for energy conversion and oxygen separation. However, liquid metal oxides possessing unique electrochemical properties still remain of limited use. The review demonstrates the potential for practical applications of molten oxides. The transport properties of molten oxide materials are discussed. The emphasis is placed on the chemical diffusion of oxygen in the molten oxide membrane materials for electrochemical energy conversion and oxygen separation. The thermodynamics of these materials is considered. The dynamic polymer chain model developed to describe the oxygen ion transport in molten oxides is discussed. Prospects for further research into molten oxide materials are outlined. The bibliography includes 145 references.

  7. Moderate Temperature Synthesis of Mesoporous Carbon

    KAUST Repository

    Dua, Rubal; Wang, Peng

    2013-01-01

    Methods and composition for preparation of mesoporous carbon material are provided. For example, in certain aspects methods for carbonization and activation at selected temperature ranges are described. Furthermore, the invention provides products prepared therefrom.

  8. Moderate Temperature Synthesis of Mesoporous Carbon

    KAUST Repository

    Dua, Rubal

    2013-01-03

    Methods and composition for preparation of mesoporous carbon material are provided. For example, in certain aspects methods for carbonization and activation at selected temperature ranges are described. Furthermore, the invention provides products prepared therefrom.

  9. Biological Applications and Transmission Electron Microscopy Investigations of Mesoporous Silica Nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Trewyn, Brian G. [Iowa State Univ., Ames, IA (United States)

    2006-01-01

    The research presented and discussed within involves the development of novel biological applications of mesoporous silica nanoparticles (MSN) and an investigation of mesoporous material by transmission electron microscopy (TEM). Mesoporous silica nanoparticles organically functionalized shown to undergo endocytosis in cancer cells and drug release from the pores was controlled intracellularly and intercellularly. Transmission electron microscopy investigations demonstrated the variety of morphologies produced in this field of mesoporous silica nanomaterial synthesis. A series of room-temperature ionic liquid (RTIL) containing mesoporous silica nanoparticle (MSN) materials with various particle morphologies, including spheres, ellipsoids, rods, and tubes, were synthesized. By changing the RTIL template, the pore morphology was tuned from the MCM-41 type of hexagonal mesopores to rotational moire type of helical channels, and to wormhole-like porous structures. These materials were used as controlled release delivery nanodevices to deliver antibacterial ionic liquids against Escherichia coli K12. The involvement of a specific organosiloxane function group, covalently attached to the exterior of fluorescein doped mesoporous silica nanoparticles (FITC-MSN), on the degree and kinetics of endocytosis in cancer and plant cells was investigated. The kinetics of endocystosis of TEG coated FITC-MSN is significantly quicker than FITC-MSN as determined by flow cytometry experiments. The fluorescence confocal microscopy investigation showed the endocytosis of TEG coated-FITC MSN triethylene glycol grafted fluorescein doped MSN (TEG coated-FITC MSN) into both KeLa cells and Tobacco root protoplasts. Once the synthesis of a controlled-release delivery system based on MCM-41-type mesoporous silica nanorods capped by disulfide bonds with superparamagnetic iron oxide nanoparticles was completed. The material was characterized by general methods and the dosage and kinetics of the

  10. Graphene oxide - Polyvinyl alcohol nanocomposite based electrode material for supercapacitors

    Science.gov (United States)

    Pawar, Pranav Bhagwan; Shukla, Shobha; Saxena, Sumit

    2016-07-01

    Supercapacitors are high capacitive energy storage devices and find applications where rapid bursts of power are required. Thus materials offering high specific capacitance are of fundamental interest in development of these electrochemical devices. Graphene oxide based nanocomposites are mechanically robust and have interesting electronic properties. These form potential electrode materials efficient for charge storage in supercapacitors. In this perspective, we investigate low cost graphene oxide based nanocomposites as electrode material for supercapacitor. Nanocomposites of graphene oxide and polyvinyl alcohol were synthesized in solution phase by integrating graphene oxide as filler in polyvinyl alcohol matrix. Structural and optical characterizations suggest the formation of graphene oxide and polyvinyl alcohol nanocomposites. These nanocomposites were found to have high specific capacitance, were cyclable, ecofriendly and economical. Our studies suggest that nanocomposites prepared by adding 0.5% wt/wt of graphene oxide in polyvinyl alcohol can be used an efficient electrode material for supercapacitors.

  11. Thermoelectric material comprising scandium doped zinc cadmium oxide

    DEFF Research Database (Denmark)

    2016-01-01

    There is presented a composition of scandium doped Zinc Cadmium Oxide with the general formula ZnzCdxScyO which the inventors have prepared, and for which material the inventors have made the insight that it is particularly advantageous as an n-type oxide material, such as particularly advantageous...

  12. Supercapacitors Based on Nickel Oxide/Carbon Materials Composites

    OpenAIRE

    Lota, Katarzyna; Sierczynska, Agnieszka; Lota, Grzegorz

    2011-01-01

    In the thesis, the properties of nickel oxide/active carbon composites as the electrode materials for supercapacitors are discussed. Composites with a different proportion of nickel oxide/carbon materials were prepared. A nickel oxide/carbon composite was prepared by chemically precipitating nickel hydroxide on an active carbon and heating the hydroxide at 300 ∘C in the air. Phase compositions of the products were characterized using X-ray diffractometry (XRD). The morphology of the composite...

  13. 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

  14. Regularities of radiation defects build up on oxide materials surface

    International Nuclear Information System (INIS)

    Bitenbaev, M.I.; Polyakov, A.I.; Tuseev, T.

    2005-01-01

    Analysis of experimental data by radiation defects study on different oxide elements (silicon, beryllium, aluminium, rare earth elements) irradiated by the photo-, gamma-, neutron-, alpha- radiation, protons and helium ions show, that gas adsorption process on the surface centers and radiation defects build up in metal oxide correlated between themselves. These processes were described by the equivalent kinetic equations for analysis of radiation defects build up in the different metal oxides. It was revealed in the result of the analysis: number of radiation defects are droningly increasing up to limit value with the treatment temperature growth. Constant of radicals death at ionizing radiation increases as well. Amount of surface defects in different oxides defining absorbing activity of these materials looks as: silicon oxide→beryllium oxide→aluminium oxide. So it was found, that most optimal material for absorbing system preparation is silicon oxide by it power intensity and berylium oxide by it adsorption efficiency

  15. Modified mesoporous silica materials for on-line separation and preconcentration of hexavalent chromium using a microcolumn coupled with flame atomic absorption spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Wang Zheng, E-mail: wangzheng@mail.sic.ac.cn [Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China); Fang Dongmei; Li Qing [Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China); East China University of Science and Technology, Shanghai 200237 (China); Zhang Lingxia; Qian Rong; Zhu Yan; Qu Haiyun [Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China); Du Yiping [East China University of Science and Technology, Shanghai 200237 (China)

    2012-05-06

    Highlights: Black-Right-Pointing-Pointer A modified SBA-15 mesoporous silica material (NH{sub 2}-SBA-15) was synthesized as sorbent. Black-Right-Pointing-Pointer The material was used for the first time in a flow injection on-line solid phase extraction (SPE) coupled with flame atomic absorption spectrometry (FAAS) to detect trace Cr (VI). Black-Right-Pointing-Pointer The NH{sub 2}-SBA-15 enables retain Cr (VI) with an enrichment factor of 44. Black-Right-Pointing-Pointer The micro-column of NH{sub 2}-SBA-15 underwent more than 100 adsorption/desorption cycles. - Abstract: A modified SBA-15 mesoporous silica material NH{sub 2}-SBA-15 was synthesized successfully by grafting {gamma}-aminopropyl-triethoxysilane. The material was characterized using transmission electron microscopy (TEM) and Fourier transform infrared/Raman (FT-IR/Raman) spectroscopy, and used for the first time in a flow injection on-line solid phase extraction (SPE) coupled with flame atomic absorption spectrometry (FAAS) to detect trace Cr (VI). Effective sorption of Cr (VI) was achieved at pH 2.0 with no interference from Cr (III) and other ions and 0.5 mol L{sup -1} NH{sub 3}{center_dot}H{sub 2}O solution was found optimal for the complete elution of Cr (VI). An enrichment factor of 44 and was achieved under optimized experimental conditions at a sample loading of 2.0 mL min{sup -1} sample loading (300 s) and an elution flow rate of 2.0 mL min{sup -1} (24 s). The precision of the 11 replicate Cr (VI) measurements was 2.1% at the 100 {mu}g L{sup -1} level with a detection limit of 0.2 {mu}g L{sup -1} (3 s, n = 10) using the FAAS. The developed method was successfully applied to trace chromium determination in waste water. The accuracy was validated using a certified reference material of riverine water (GBW08607).

  16. 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).

  17. Nanostructured manganese oxide thin films as electrode material for supercapacitors

    Science.gov (United States)

    Xia, Hui; Lai, Man On; Lu, Li

    2011-01-01

    Electrochemical capacitors, also called supercapacitors, are alternative energy storage devices, particularly for applications requiring high power densities. Recently, manganese oxides have been extensively evaluated as electrode materials for supercapacitors due to their low cost, environmental benignity, and promising supercapacitive performance. In order to maximize the utilization of manganese oxides as the electrode material for the supercapacitors and improve their supercapacitive performance, the nanostructured manganese oxides have therefore been developed. This paper reviews the synthesis of the nanostructured manganese oxide thin films by different methods and the supercapacitive performance of different nanostructures.

  18. 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.

  19. 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.

  20. Synthesis and electrochemical characterization of mesoporous Li2FeSiO4/C composite cathode material for Li-ion batteries

    Science.gov (United States)

    Kumar, Ajay; Jayakumar, O. D.; Bazzi, Khadije; Nazri, Gholam-Abbas; Naik, Vaman M.; Naik, Ratna

    2015-03-01

    Lithium iron silicate (Li2FeSiO4) has the potential as cathode for Li ion batteries due to its high theoretical capacity (~ 330 mAh/g) and improved safety. The application of Li2FeSiO4 as cathode material has been challenged by its poor electronic conductivity and slow lithium ion diffusion in the solid phase. In order to solve these problems, we have synthesized mesoporous Li2FeSiO4/C composites by sol-gel method using the tri-block copolymer (P123) as carbon source. The phase purity and morphology of the composite materials were characterized by x-ray diffraction, SEM and TEM. The XRD pattern confirmed the formation of ~ 12 nm size Li2FeSiO4 crystallites in composites annealed at 600 °C for 6 h under argon atmosphere. The electrochemical properties are measured using the composite material as positive electrode in a standard coin cell configuration with lithium as the active anode and the cells were tested using AC impedance spectroscopy, cyclic voltammetry, and galvanostatic charge/discharge cycling. The Li2FeSiO4/C composites showed a discharge capacity of ~ 240 mAh/g at a rate of C/30 at room temperature. The effect of different annealing temperature and synthesis time on the electrochemical performance of Li2FeSiO4/C will be presented.

  1. Solid-Phase Extraction of Hemoglobin from Human Whole Blood with a Coordination-Polymer-Derived Composite Material Based on ZnO and Mesoporous Carbon.

    Science.gov (United States)

    Jia, Yuan; Xu, Xinxin; Ou, Jinzhao; Liu, Xiaoxia

    2017-11-13

    A composite material, ZnO@MC, has been synthesized successfully by calcination using a one-dimensional zinc-based coordination polymer as the precursor. In ZnO@MC, ZnO particles with a size of about 5-8 nm are dispersed evenly in a mesoporous carbon matrix. Adsorption experiments at pH 6.8 with 2 mg ZnO@MC as adsorbent illustrated an adsorption efficiency of 92.3 % in 5 mL hemoglobin (Hb) solution with a concentration of 100 mg L -1 . In contrast, the adsorption of bovine serum albumin can almost be ignored under the same conditions. The selectivity originates from a strong Zn II -histidine interaction between ZnO@MC and hemoglobin. The adsorption behavior of hemoglobin on ZnO@MC fits the Temkin model perfectly with a capacity as high as 11646 mg g -1 . The hemoglobin adsorbed on the composite material can be eluted easily with sodium dodecyl sulfate stripping reagent with an extraction efficiency of 87.7 %. Circular dichroism spectra and protein activity studies suggest the structure and biological activity of hemoglobin is the same before and after the adsorption/desorption experiment. Finally, the ZnO@MC composite material was employed to extract hemoglobin from human whole blood without any pretreatment, and gave a very satisfactory result. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. 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.

  3. Oxide materials as positive electrodes of lithium-ion batteries

    International Nuclear Information System (INIS)

    Makhonina, Elena V; Pervov, Vladislav S; Dubasova, Valeriya S

    2004-01-01

    The published data on oxide materials as positive electrodes for lithium-ion batteries are described systematically. The mechanisms of structural changes in cathode materials occurring during the operation of lithium-ion batteries and the problems concerned with their selection are discussed. Modern trends in optimising cathode materials and lithium-ion batteries on the whole are considered.

  4. Mesoporous templated silicas: stability, pore size engineering and catalytic activation

    International Nuclear Information System (INIS)

    Vansant, Etienne

    2003-01-01

    The Laboratory of Adsorption and Catalysis has focused its research activities on the synthesis and activation of new porous materials. In the past few years, we have succeeded in developing easy and reproducible pathways to synthesize a huge variety of mesoporous crystalline materials. Points of interest in the synthesis of Mesoporous Templated Silicas are (i) stabilization of the structure, to withstand hydrothermal, thermal and mechanical pressure, (ii) pore size engineering to systematically control the pore size, pore volume and the ratio micro/mesopores and (iii) ease and reproducibility of the synthesis procedure, applying green principles, such as template recuperation. By carefully adapting the synthesis conditions and composition of the synthesis gel, using surfactants (long chain quaternary ammonium ions) and co-templates (long chain amines, alcohols or alkanes), the pore size of the obtained materials can be controlled from 1.5 to 7.0 nm, retaining the very narrow pore size distribution. Alternatively, materials with combined micro- and mesoporosity can be synthesized, using neutral surfactants (triblock copolymers). Hereby, the optimization of the SBA-15 and SBA-16 synthesis is being done in order to create mesoporous materials with microporous walls. The second research line is the controlled activation of MTS materials, by grafting or incorporation of catalytic active centers. We have developed for this purpose the Molecular Designed Dispersion method, which uses metal diketonate complexes as precursors. It is shown that in all cases the dispersion of the metal oxides on the surface is much better compared to the conventional grafting techniques. We have studied and published activation with V, Ti, Mo, Fe, Al and Cr species on different MTS materials. The structure and location of the active metal ion is the subject of an extensive spectroscopic investigation, using FT-IR, FT-Raman, UV-Vis DR coupled with selective chemisorption experiments and

  5. 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.

  6. 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)

  7. Methods for making lithium vanadium oxide electrode materials

    Science.gov (United States)

    Schutts, Scott M.; Kinney, Robert J.

    2000-01-01

    A method of making vanadium oxide formulations is presented. In one method of preparing lithium vanadium oxide for use as an electrode material, the method involves: admixing a particulate form of a lithium compound and a particulate form of a vanadium compound; jet milling the particulate admixture of the lithium and vanadium compounds; and heating the jet milled particulate admixture at a temperature below the melting temperature of the admixture to form lithium vanadium oxide.

  8. Liquid Photonic Crystals for Mesopore Detection.

    Science.gov (United States)

    Zhu, Biting; Fu, Qianqian; Chen, Ke; Ge, Jianping

    2018-01-02

    Nitrogen adsorption-desorption for mesopore characterization requires the using of expensive instrumentation, time-consuming processes, and the consumption of liquid nitrogen. Herein, a new method is developed to measure the pore parameters through mixing a mesoporous substance with a supersaturated SiO 2 colloidal solution at different temperatures, and subsequent rapid measurement of reflection changes of the precipitated liquid photonic crystals. The pore volumes and diameters of mesoporous silica were measured according to the positive correlation between unit mass reflection change (Δλ/m) and pore volume (V), and the negative correlation between average absorption temperature (T) and pore diameter (D). This new approach may provide an alternative method for fast, convenient and economical characterization of mesoporous materials. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Carbon dioxide adsorption on micro-mesoporous composite materials of ZSM-12/MCM-48 type: The role of the contents of zeolite and functionalized amine

    Energy Technology Data Exchange (ETDEWEB)

    Santos, S.C.G. [Federal University of Sergipe, Materials Science and Engineering Postgraduate Program P" 2CEM, São Cristovão/SE (Brazil); Pedrosa, A.M.Garrido [Federal University of Sergipe, Departament of Chemistry (DQI), São Cristovão/SE (Brazil); Souza, M.J.B., E-mail: mjbsufs@gmail.com [Federal University of Sergipe, Department of Chemical Engineering (DEQ), Av. Marechal Rondon S/N, 49100-000, São Cristovão/SE (Brazil); Cecilia, J.A.; Rodríguez-Castellón, E. [University of Málaga, Department of Inorganic Chemistry, Crystallography and Mineralogy, Faculty of Sciences, 29071, Málaga (Spain)

    2015-10-15

    Highlights: • Synthesis of the micro-mesoporous composite materials of ZSM-12/MCM-48 type. • Application of these adsorbents in the carbon dioxide adsorption. • Effects of the contents of zeolite and amino group in the material surface on the CO{sub 2} capture efficiency. - Abstract: In this study ZSM-12/MCM-48 adsorbents have been synthesized at three ZSM-12 content, and also were functionalizated with amine groups by grafting. All the adsorbents synthesized were evaluated for CO{sub 2} capture. The X-ray diffraction analysis of the ZSM-12/MCM-48 composite showed the main characteristic peaks of ZSM-12 and MCM-48, and after the functionalization, the structure of MCM-48 on the composite impregnated was affected due amine presence. For the composites without amine, the ZSM-12 content was the factor determining in the adsorption capacity of CO{sub 2} and for the composites with amine the amount of amine was that influenced in the adsorption capacity.

  10. Solid oxide fuel cell (SOFC) materials

    CERN Document Server

    Saravanan, R

    2018-01-01

    Developing materials for SOFC applications is one of the key topics in energy research. The book focuses on manganite structured materials, such as doped lanthanum chromites and lanthanum manganites, which have interesting properties: thermal and chemical stability, mixed ionic and electrical conductivity, electrocatalytic activity, magnetocaloric property and colossal magnetoresistance (CMR).

  11. Activated Porous Carbon Spheres with Customized Mesopores through Assembly of Diblock Copolymers for Electrochemical Capacitor.

    Science.gov (United States)

    Tang, Jing; Wang, Jie; Shrestha, Lok Kumar; Hossain, Md Shahriar A; Alothman, Zeid Abdullah; Yamauchi, Yusuke; Ariga, Katsuhiko

    2017-06-07

    A series of porous carbon spheres with precisely adjustable mesopores (4-16 nm), high specific surface area (SSA, ∼2000 m 2 g -1 ), and submicrometer particle size (∼300 nm) was synthesized through a facile coassembly of diblock polymer micelles with a nontoxic dopamine source and a common postactivation process. The mesopore size can be controlled by the diblock polymer, polystyrene-block-poly(ethylene oxide) (PS-b-PEO) templates, and has an almost linear dependence on the square root of the degree of polymerization of the PS blocks. These advantageous structural properties make the product a promising electrode material for electrochemical capacitors. The electrochemical capacitive performance was studied carefully by using symmetrical cells in a typical organic electrolyte of 1 M tetraethylammonium tetrafluoroborate/acetonitrile (TEA BF 4 /AN) or in an ionic liquid electrolyte of 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIMBF 4 ), displaying a high specific capacitance of 111 and 170 F g -1 at 1 A g -1 , respectively. The impacts of pore size distribution on the capacitance performance were thoroughly investigated. It was revealed that large mesopores and a relatively low ratio of micropores are ideal for realizing high SSA-normalized capacitance. These results provide us with a simple and reliable way to screen future porous carbon materials for electrochemical capacitors and encourage researchers to design porous carbon with high specific surface area, large mesopores, and a moderate proportion of micropores.

  12. Preparation and physical characterization of calcium sulfate cement/silica-based mesoporous material composites for controlled release of BMP-2

    Directory of Open Access Journals (Sweden)

    Tan H

    2015-07-01

    Full Text Available Honglue Tan,1 Shengbing Yang,2 Pengyi Dai,1 Wuyin Li,1 Bing Yue2 1Luoyang Orthopedics and Traumatology Institution, Luoyang Orthopedic-Traumatological Hospital, Luoyang, 2Shanghai Key Laboratory of Orthopedic Implants, Department of Orthopedic Surgery, Shanghai Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, People’s Republic of China Abstract: As a commonly used implant material, calcium sulfate cement (CSC, has some shortcomings, including low compressive strength, weak osteoinduction capability, and rapid degradation. In this study, silica-based mesoporous materials such as SBA-15 were synthesized and combined with CSC to prepare CSC/SBA-15 composites. The properties of SBA-15 were characterized by X-ray diffraction, transmission electron microscopy, and nitrogen adsorption–desorption isotherms. SBA-15 was blended into CSC at 0, 5, 10, and 20 wt%, referred to as CSC, CSC-5S (5% mass ratio, CSC-10S (10% mass ratio, and CSC-20S (20% mass ratio, respectively. Fourier-transform infrared spectroscopy and compression tests were used to determine the structure and mechanical properties of the composites, respectively. The formation of hydroxyapatite on composite surfaces was analyzed using scanning electron microscopy and X-ray diffraction after soaking in simulated body fluid. BMP-2 was loaded into the composites by vacuum freeze-drying, and its release characteristics were detected by Bradford protein assay. The in vitro degradation of the CSC/SBA-15 composite was investigated by measuring weight loss. The results showed that the orderly, nanostructured, mesoporous SBA-15 possessed regular pore size and structure. The compressive strength of CSC/SBA-15 increased with the increase in SBA-15 mass ratio, and CSC-20S demonstrated the maximum strength. Compared to CSC, hydroxyapatite that formed on the surfaces of CSC/SBA-15 was uniform and compact. The degradation rate of CSC/SBA-15 decreased with increasing

  13. Functionalized bimodal mesoporous silicas as carriers for controlled aspirin delivery

    Science.gov (United States)

    Gao, Lin; Sun, Jihong; Li, Yuzhen

    2011-08-01

    The bimodal mesoporous silica modified with 3-aminopropyltriethoxysilane was performed as the aspirin carrier. The samples' structure, drug loading and release profiles were characterized with X-ray diffraction, scanning electron microscopy, N 2 adsorption and desorption, Fourier transform infrared spectroscopy, TG analysis, elemental analysis and UV-spectrophotometer. For further exploring the effects of the bimodal mesopores on the drug delivery behavior, the unimodal mesoporous material MCM-41 was also modified as the aspirin carrier. Meantime, Korsmeyer-Peppas equation ft= ktn was employed to analyze the dissolution data in details. It is indicated that the bimodal mesopores are beneficial for unrestricted drug molecules diffusing and therefore lead to a higher loading and faster releasing than that of MCM-41. The results show that the aspirin delivery properties are influenced considerably by the mesoporous matrix, whereas the large pore of bimodal mesoporous silica is the key point for the improved controlled-release properties.

  14. Mesoporous zeolite and zeotype single crystals synthesized in fluoride media

    DEFF Research Database (Denmark)

    Egeblad, Kresten; Kustova, Marina; Klitgaard, Søren Kegnæs

    2007-01-01

    We report the synthesis and characterization of a series of new mesoporous zeolite and zeotype materials made available by combining new and improved procedures for directly introducing carbon into reaction mixtures with the fluoride route for conventional zeolite synthesis. The mesoporous...... materials were all prepared by hydrothermal crystallization of gels adsorbed on carbon matrices which were subsequently removed by combustion. The procedures presented here resulted in mesoporous zeolite and zeotypes materials with MFI, MEL, BEA, AFI and CHA framework structures. All samples were...... characterized by XRPD, SEM, TEM and N-2 physisorption measurements. For the zeolite materials it A as found that mesoporous MFI and MEL structured single crystals could indeed be crystallized from fluoride media using an improved carbon-templating approach. More importantly, it was found that mesoporous BEA...

  15. 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.

  16. 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.

  17. Ultralight mesoporous magnetic frameworks by interfacial assembly of Prussian blue nanocubes.

    Science.gov (United States)

    Kong, Biao; Tang, Jing; Wu, Zhangxiong; Wei, Jing; Wu, Hao; Wang, Yongcheng; Zheng, Gengfeng; Zhao, Dongyuan

    2014-03-10

    A facile approach for the synthesis of ultralight iron oxide hierarchical structures with tailorable macro- and mesoporosity is reported. This method entails the growth of porous Prussian blue (PB) single crystals on the surface of a polyurethane sponge, followed by in situ thermal conversion of PB crystals into three-dimensional mesoporous iron oxide (3DMI) architectures. Compared to previously reported ultralight materials, the 3DMI architectures possess hierarchical macro- and mesoporous frameworks with multiple advantageous features, including high surface area (ca. 117 m(2) g(-1)) and ultralow density (6-11 mg cm(-3)). Furthermore, they can be synthesized on a kilogram scale. More importantly, these 3DMI structures exhibit superparamagnetism and tunable hydrophilicity/hydrophobicity, thus allowing for efficient multiphase interfacial adsorption and fast multiphase catalysis. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Research Progress on Synthesis of Lignin-derived Mesoporous Carbon Materials via Template Strategy%模板法制备木质素基中孔炭材料研究进展

    Institute of Scientific and Technical Information of China (English)

    宋曜光; 刘军利; 许伟; 孙康

    2018-01-01

    Lignin is one of the three recalcitrant components of lignocellulosic renewable biomass and the most abundant heterogeneous aromatic structural biopolymer on the earth. Lignin has a high carbon content over 50 %,and is one of the potential ideal precursors for carbon materials.Mesoporous carbon with high specific surface area and big pore size has wide applications on biomedical devices, catalysis, supercapacitors and so on. Therefore, the synthesis of mesoporous carbon materials has successfully concentrated attention and efforts by scientists worldwide. Nano-casting techniques are available method to prepare mesoporous carbons. Herein, some common strategies for pore dimension adjusting such as hard template route, soft template route and dual template route were reviewed.Finally,the recent research progress on the preparation of lignin-derived mesoporous carbon materials by using template strategy was emphatically introduced.%木质素是3种木质纤维类可再生生物质资源之一,同时是自然界中含量最丰富的芳香类天然高分子聚合物,其含碳量超过50 %,是制备炭材料的理想前驱体.中孔炭材料具有比表面积高、孔径大等特点,在医学器件、催化、超级电容器等方面有着广泛的应用,模板法是制备中孔炭材料的常用方法.主要介绍以木质素为碳前驱体通过硬模板法、软模板法以及双模板法制备中孔炭材料并调控孔结构,重点介绍了制备最新进展.

  19. Pt20RuxSny nanoparticles dispersed on mesoporous carbon CMK-3 and their application in the oxidation of 2-carbon alcohols and fermentation effluent

    International Nuclear Information System (INIS)

    Lo, An-Ya; Chung, Yi-Chen; Hung, Wei-Hsuan; Hsu, Yun-Chi; Tseng, Chuan-Ming; Zhang, Wei-Lun; Wang, Fu-Kai; Lin, Chiu-Yue

    2017-01-01

    Highlights: • Pt 20 Ru x Sn y @C catalysts are formed by dispersing Pt-Sn and Pt-Ru-Sn NPs on CMK-3. • They are tested in fuel cells using ethanol, ethylene glycol, and CFHPE as fuels. • Higher Sn contents improve catalytic efficiency of Pt 20 Ru x Sn y when x = 0 or x = 10. • Role of Sn in C−C bond cleavage and improving poisoning tolerance is explained. • Pt 20 Ru 10 Sn 15 @C is used to show feasibility of using bioalcohol from CFHPE as fuel. - Abstract: We report the synthesis of Pt-Sn binary and Pt-Ru-Sn ternary alloy nanoparticles (NPs) dispersed on mesoporous carbon CMK-3 for bioalcohol fuel cell applications where ethanol, ethylene glycol, and fermentative hydrogen production effluent were used as the fuels. The proposed alloy electrocatalysts, denoted as Pt 20 Ru x Sn y @C (where 20, x, and y represent the weight fractions of Pt, Ru, and Sn, respectively), were examined using scanning electron microscopy, energy-dispersive X-ray spectroscopy mapping, transmission electron microscopy, Brunauer-Emmett-Teller measurements, X-ray diffraction analysis, and electrochemical measurements, in order to determine their morphologies, microstructures, compositions, phase structures, and electrochemical characteristics. The effects of the Sn content on the following factors were examined: 1) average particle size of the alloy NPs, 2) mesoporosity, 3) electrochemically active surfaces of Pt 20 Ru x Sn y @C, and 4) ethanol oxidation reaction and ethylene glycol oxidation reaction activities. Higher Sn contents improved the catalytic efficiency of Pt 20 Ru x Sn y when x = 0 or x = 10, with the optimized compositions being Pt 20 Sn 30 and Pt 20 Ru 10 Sn 15 for the binary and ternary alloys, respectively. Based on the ethanol and ethylene glycol oxidation reactions, we explain the role of Sn in promoting C−C bond cleavage and in improving catalyst tolerance against poisoning. Overall, for both the ethanol system and the ethylene glycol system, the catalytic

  20. Effect of preparation procedure on the formation of nanosized mesoporous TiO2-CeO2 catalysts for ethyl acetate total oxidation and methanol decomposition

    Czech Academy of Sciences Publication Activity Database

    Mileva, A.; Issa, G.; Henych, Jiří; Štengl, Václav; Kovacheva, D.; Tsoncheva, T.

    2016-01-01

    Roč. 48, G (2016), s. 115-119 ISSN 0324-1130. [Scientific Session on Advanced Materials and Technologies. Sofia, 10.10.2016-11.10.2016] R&D Projects: GA MŠk(CZ) LM2015073 Institutional support: RVO:61388980 Keywords : Ti-Ce oxides * ethyl acetate total oxidation * methanol decomposition Subject RIV: CA - Inorganic Chemistry Impact factor: 0.238, year: 2016 http://www.bcc.bas.bg/BCC_Volumes/Volume_48_Special_G_2016

  1. Manganese oxide-based materials as electrochemical supercapacitor electrodes.

    Science.gov (United States)

    Wei, Weifeng; Cui, Xinwei; Chen, Weixing; Ivey, Douglas G

    2011-03-01

    Electrochemical supercapacitors (ECs), characteristic of high power and reasonably high energy densities, have become a versatile solution to various emerging energy applications. This critical review describes some materials science aspects on manganese oxide-based materials for these applications, primarily including the strategic design and fabrication of these electrode materials. Nanostructurization, chemical modification and incorporation with high surface area, conductive nanoarchitectures are the three major strategies in the development of high-performance manganese oxide-based electrodes for EC applications. Numerous works reviewed herein have shown enhanced electrochemical performance in the manganese oxide-based electrode materials. However, many fundamental questions remain unanswered, particularly with respect to characterization and understanding of electron transfer and atomic transport of the electrochemical interface processes within the manganese oxide-based electrodes. In order to fully exploit the potential of manganese oxide-based electrode materials, an unambiguous appreciation of these basic questions and optimization of synthesis parameters and material properties are critical for the further development of EC devices (233 references).

  2. Scandium-doped zinc cadmium oxide as a new stable n-type oxide thermoelectric material

    DEFF Research Database (Denmark)

    Han, Li; Christensen, Dennis Valbjørn; Bhowmik, Arghya

    2016-01-01

    Scandium-doped zinc cadmium oxide (Sc-doped ZnCdO) is proposed as a new n-type oxide thermoelectric material. The material is sintered in air to maintain the oxygen stoichiometry and avoid instability issues. The successful alloying of CdO with ZnO at a molar ratio of 1 : 9 significantly reduced...... is a good candidate for improving the overall conversion efficiencies in oxide thermoelectric modules. Meanwhile, Sc-doped ZnCdO is robust in air at high temperatures, whereas other n-type materials, such as Al-doped ZnO, will experience rapid degradation of their electrical conductivity and ZT....

  3. Tungsten oxide nanowires grown on graphene oxide sheets as high-performance electrochromic material

    International Nuclear Information System (INIS)

    Chang, Xueting; Sun, Shibin; Dong, Lihua; Hu, Xiong; Yin, Yansheng

    2014-01-01

    Graphical abstract: Electrochromic mechanism of tungsten oxide nanowires-reduced graphene oxide composite. - Highlights: • A novel inorganic-nano-carbon hybrid composite was prepared. • The hybrid composite has sandwich-like structure. • The hybrid composite exhibited high-quality electrohcromic performance. - Abstract: In this work, we report the synthesis of a novel hybrid electrochromic composite through nucleation and growth of ultrathin tungsten oxide nanowires on graphene oxide sheets using a facile solvothermal route. The competition between the growth of tungsten oxide nanowires and the reduction of graphene oxide sheets leads to the formation of sandwich-structured tungsten oxide-reduced graphene oxide composite. Due to the strongly coupled effect between the ultrathin tungsten oxide nanowires and the reduced graphene oxide nanosheets, the novel electrochromic composite exhibited high-quality electrochromic performance with fast color-switching speed, good cyclic stability, and high coloration efficiency. The present tungsten oxide-reduced graphene oxide composite represents a new approach to prepare other inorganic-reduced graphene oxide hybrid materials for electrochemical applications

  4. Fundamental Material Properties Underlying Solid Oxide Electrochemistry

    DEFF Research Database (Denmark)

    Mogensen, Mogens Bjerg; Hansen, Karin Vels; Holtappels, Peter

    2012-01-01

    , and the electrochemical reactions take place at elevated temperatures from 300 and up to 1000 C. This has as consequence that the region around the threephase- boundary (TPB), where the electron conducting electrode, the electrolyte and the gas phase reactants meet, is the region where the electrochemical processes take...... place. The length of the TPB is a key factor even though the width and depth of the zone, in which the rate limiting reactions take place, may vary depending of the degree of the electrode materials ability to conduct both electrons and ions, i.e. the TPB zone volume depends on how good a mixed ionic...... in the TPB region. Also, segregations to the surfaces and interfaces of the electrode materials, which may affect the electrode reaction mechanism, are very dependent on the exact history of fabrication and operation. The positive effects of even small concentrations of nanoparticles in the electrodes may...

  5. Metal Oxide Nanostructured Materials for Optical and Energy Applications

    OpenAIRE

    Moore, Michael Christopher

    2013-01-01

    With a rapidly growing population, dwindling resources, and increasing environmental pressures, the need for sustainable technological solutions becomes more urgent. Metal oxides make up much of the earth's crust and are typically inexpensive materials, but poor electrical and optical properties prevent them from being useful for most semiconductor applications. Recent breakthroughs in chemistry and materials science allow for the growth of high-quality materials with nanometer-scale features...

  6. TiO2-coated mesoporous carbon: conventional vs. microwave-annealing process.

    Science.gov (United States)

    Coromelci-Pastravanu, Cristina; Ignat, Maria; Popovici, Evelini; Harabagiu, Valeria

    2014-08-15

    The study of coating mesoporous carbon materials with titanium oxide nanoparticles is now becoming a promising and challenging area of research. To optimize the use of carbon materials in various applications, it is necessary to attach functional groups or other nanostructures to their surface. The combination of the distinctive properties of mesoporous carbon materials and titanium oxide is expected to be applied in field emission displays, nanoelectronic devices, novel catalysts, and polymer or ceramic reinforcement. But, their synthesis is still largely based on conventional techniques, such as wet impregnation followed by chemical reduction of the metal nanoparticle precursors, which takes time and money. The thermal heating based techniques are time consuming and often lack control of particle size and morphology. Hence, since there is a growing interest in microwave technology, an alternative way of power input into chemical reactions through dielectric heating is the use of microwaves. This work is focused on the advantages of microwave-assisted synthesis of TiO2-coated mesoporous carbon over conventional thermal heating method. The reviewed studies showed that the microwave-assisted synthesis of such composites allows processes to be completed within a shorter reaction time allowing the nanoparticles formation with superior properties than that obtained by conventional method. Copyright © 2014 Elsevier B.V. All rights reserved.

  7. 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.

  8. Hierarchical zeolites: progress on synthesis and characterization of mesoporous zeolite single crystal catalysts

    DEFF Research Database (Denmark)

    Kustova, Marina; Egeblad, Kresten; Christensen, Claus H.

    2007-01-01

    Recently, a new family of crystalline zeolitic materials was reported, the so-called mesoporous zeolite single crystals featuring individual zeolite single crystals with an additional noncrystalline mesopore system interconnected with the usual micropore system of the zeolite, resulting...... measurements. Additionally, the results of diffusion of n-hexadecane in conventional and mesoporous zeolites are presented. Isomerization and cracking of n-hexadecane was chosen as model test reaction for these materials. All results support that mesoporous zeolites are superior catalysts due to improved mass...... transport. Importantly, the mesoporous zeolites show significant improved resistance to poisoning by carbon formation....

  9. 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

  10. Soft-Template Synthesis of Mesoporous Anatase TiO2 Nanospheres and Its Enhanced Photoactivity

    Directory of Open Access Journals (Sweden)

    Xiaojia Li

    2017-11-01

    Full Text Available Highly crystalline mesoporous anatase TiO2 nanospheres with high surface area (higher than P25 and anatase TiO2 are prepared by a soft-template method. Despite the high specific surface area, these samples have three times lower equilibrium adsorption (<2% than Degussa P25. The rate constant of the mesoporous anatase TiO2 (0.024 min−1 reported here is 364% higher than that of P25 (0.0066 min−1, for the same catalytic loading. The results of oxidation-extraction photometry using several reactive oxygen species (ROS scavengers indicated that mesoporous anatase TiO2 generates more ROS than P25 under UV-light irradiation. This significant improvement in the photocatalytic performance of mesoporous spherical TiO2 arises from the following synergistic effects in the reported sample: (i high surface area; (ii improved crystallinity; (iii narrow pore wall thicknesses (ensuring the rapid migration of photogenerated carriers to the surface of the material; and (iv greater ROS generation under UV-light.

  11. Soft-Template Synthesis of Mesoporous Anatase TiO₂ Nanospheres and Its Enhanced Photoactivity.

    Science.gov (United States)

    Li, Xiaojia; Zou, Mingming; Wang, Yang

    2017-11-10

    Highly crystalline mesoporous anatase TiO₂ nanospheres with high surface area (higher than P25 and anatase TiO₂) are prepared by a soft-template method. Despite the high specific surface area, these samples have three times lower equilibrium adsorption (<2%) than Degussa P25. The rate constant of the mesoporous anatase TiO₂ (0.024 min -1 ) reported here is 364% higher than that of P25 (0.0066 min -1 ), for the same catalytic loading. The results of oxidation-extraction photometry using several reactive oxygen species (ROS) scavengers indicated that mesoporous anatase TiO₂ generates more ROS than P25 under UV-light irradiation. This significant improvement in the photocatalytic performance of mesoporous spherical TiO₂ arises from the following synergistic effects in the reported sample: (i) high surface area; (ii) improved crystallinity; (iii) narrow pore wall thicknesses (ensuring the rapid migration of photogenerated carriers to the surface of the material); and (iv) greater ROS generation under UV-light.

  12. 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.

  13. Supercapacitors Based on Nickel Oxide/Carbon Materials Composites

    Directory of Open Access Journals (Sweden)

    Katarzyna Lota

    2011-01-01

    Full Text Available In the thesis, the properties of nickel oxide/active carbon composites as the electrode materials for supercapacitors are discussed. Composites with a different proportion of nickel oxide/carbon materials were prepared. A nickel oxide/carbon composite was prepared by chemically precipitating nickel hydroxide on an active carbon and heating the hydroxide at 300 ∘C in the air. Phase compositions of the products were characterized using X-ray diffractometry (XRD. The morphology of the composites was observed by SEM. The electrochemical performances of composite electrodes used in electrochemical capacitors were studied in addition to the properties of electrode consisting of separate active carbon and nickel oxide only. The electrochemical measurements were carried out using cyclic voltammetry, galvanostatic charge/discharge, and impedance spectroscopy. The composites were tested in 6 M KOH aqueous electrolyte using two- and three-electrode Swagelok systems. The results showed that adding only a few percent of nickel oxide to active carbon provided the highest value of capacity. It is the confirmation of the fact that such an amount of nickel oxide is optimal to take advantage of both components of the composite, which additionally can be a good solution as a negative electrode in asymmetric configuration of electrode materials in an electrochemical capacitor.

  14. MCM-41介孔碳材料的合成及其电化学性能%Synthesis of MCM-41 Mesoporous Carbon Materials and Their Electrochemical Performance

    Institute of Scientific and Technical Information of China (English)

    宋伟明; 徐立洋; 孙立; 邓启刚; 冯建; 程晓宇

    2017-01-01

    以十六烷基三甲基溴化铵(CTAB)为模板剂,可溶性淀粉(Starch)为碳源,通过软模板法一步合成了高度有序的介孔碳材料.通过热重分析(TG)、X射线衍射(XRD)、N2吸附-脱附和透射电子显微镜(TEM)对材料的结构进行了表征.结果表明:当m(模板剂CTAB)∶m(可溶性淀粉)=1.0∶1.5,650℃焙烧碳化3h,并用氢氟酸去除二氧化硅后,所得到的MCM-41有序介孔碳材料(OMC-650)的比表面积为985 m2/g,平均孔径为2.5nm,且孔径分布均匀.XRD和FEM分析结果表明,OMC-650具有典型的MCM-41结构特征,有序性良好.以OMC-650作为工作电极,氧化汞为参比电极,铂为辅助电极,用6 mol/L KOH做电解液,测其比电容为150 F/g,且经过1 000次充放电循环后,其比电容仍为138 F/g,为原电容的92%,说明所合成的材料具有良好的电容稳定性.%A highly ordered mesoporous carbon material was synthesized by a soft template method with hexadecyltrimethylammonium bromide (CTAB) as a template and soluble starch (Starch) as a carbon source.The structures of the resultant materials were characterized by thermal gravimetric analysis (TG),X-ray diffraction (XRD),N2 adsorption-desorption isotherms and transmission electron microscopy (TEM).The results showed that MCM-41 ordered mesoporous carbon material (OMC-650) was obtained when the mass ratio of CTAB to Starch was 1.0∶1.5,carbonized for 3 h at 650 ℃,and then removing the silica with hydrofluoric acid.OMC-650 possessed specific surface area of 985 m2/g and average pore diameter of 2.5 nm and exhibited a uniform distribution.XRD and TEM analysis showed that OMC-650 possesses a typical MCM-41 structural feature with high ordered structure.The electrochemical tests were conducted in a three-electrode system in 6 mol/L KOH solution.When OMC-650 was used as a working electrode,mercury oxide electrode was used as a reference electrode,and Pt wire electrode served as an auxiliary electrode.The specific capacitance of

  15. 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 ...

  16. Novel hybrid materials based on the vanadium oxide nanobelts

    Energy Technology Data Exchange (ETDEWEB)

    Zabrodina, G.S., E-mail: kudgs@mail.ru [G.A. Razuvaev Institute of Organometallic Chemistry of Russian Academy of Sciences, Nizhny Novgorod 603950 (Russian Federation); Lobachevsky State University, Nizhny Novgorod 603950 (Russian Federation); Makarov, S.G.; Kremlev, K.V. [G.A. Razuvaev Institute of Organometallic Chemistry of Russian Academy of Sciences, Nizhny Novgorod 603950 (Russian Federation); Lobachevsky State University, Nizhny Novgorod 603950 (Russian Federation); Yunin, P.A.; Gusev, S.A. [Institute for Physics of Microstructures Russian Academy of Sciences, Nizhny Novgorod 603087 (Russian Federation); Kaverin, B.S.; Kaverina, L.B. [G.A. Razuvaev Institute of Organometallic Chemistry of Russian Academy of Sciences, Nizhny Novgorod 603950 (Russian Federation); Ketkov, S.Yu. [G.A. Razuvaev Institute of Organometallic Chemistry of Russian Academy of Sciences, Nizhny Novgorod 603950 (Russian Federation); Lobachevsky State University, Nizhny Novgorod 603950 (Russian Federation)

    2016-04-15

    Graphical abstract: - Highlights: • Flat and curved vanadium oxide nanobelts have been synthesized. • Hybrid material was prepared via decoration of flexible nanobelts with zinc phthalocyanine. • Investigations of the thermal stability, morphologies and structures were carried out. - Abstract: Novel hybrid materials based on zinc phthalocyanine and nanostructured vanadium oxides have attracted extensive attention for the development of academic research and innovative industrial applications such as flexible electronics, optical sensors and heterogeneous catalysts. Vanadium oxides nanobelts were synthesized via a hydrothermal treatment V{sub 2}O{sub 5}·nH{sub 2}O gel with surfactants (TBAB, CTAB) used as structure-directing agents, where CTAB – cetyltrimethylammonium bromide, TBAB – tetrabutylammonium bromide. Hybrid materials were prepared decoration of (CTA){sub 0.33}V{sub 2}O{sub 5} flexible nanobelts with cationic zinc phthalocyanine by the ion-exchange route. Investigations of the thermal stability, morphologies and structures of the (CTA){sub 0.33}V{sub 2}O{sub 5}, (TBA){sub 0.16}V{sub 2}O{sub 5} nanobelts and zinc phthalocyanine exchange product were carried out. The hybrid materials based on the nanostructured vanadium oxide and zinc phthalocyanine were tested as photocatalysts for oxidation of citronellol and 2-mercaptoethanol by dioxygen.

  17. Exoelectrogenic biofilm as a template for sustainable formation of a catalytic mesoporous structure

    KAUST Repository

    Yates, Matthew D.

    2014-06-04

    © 2014 Wiley Periodicals, Inc. Actively respiring biofilms of Geobacter sulfurreducens were used as a biotemplate to form a palladium mesoporous layer directly on an electrode surface. Cells and proteins within the biofilm acted as the reductant and stabilizer to facilitate the reduction, dispersion, and attachment of palladium nanoparticles to the electrode surface without using synthetic chemicals. © 2014 Wiley Periodicals, Inc. Mesoporous structures can increase catalytic activity by maximizing the ratio of surface area to volume, but current synthesis techniques utilize expensive polymers and toxic chemicals. A Geobacter sulfurreducens biofilm was used as a sustainable template to form mesoporous Pd structures while eliminating the need for synthetic chemicals. The bulk of the biofilm material was removed by thermal treatments after nanoparticle formation, producing a catalytic Pd mesoporous (pore size 9.7±0.1nm) structure attached to the graphite electrode with a 1.5-2μm thick backbone composed of nanoparticles (~200nm). A control electrode electrochemically plated with Pd in the absence of a biofilm exhibited a variable planar Pd base (~0.5-3μm thick) with sporadic Pd extrusions (~2μm across, 1-5μm tall) from the surface. The biotemplated mesoporous structure produced 15-20% higher stable current densities during H2 oxidation tests than the electrochemically plated control electrode, even though 30% less Pd was present in the biotemplated catalyst. These results indicate that electroactive biofilms can be used as a sustainable base material to produce nanoporous structures without the need for synthetic polymers. Biotechnol. Bioeng. 2014;111: 2349-2354.

  18. Exoelectrogenic biofilm as a template for sustainable formation of a catalytic mesoporous structure

    KAUST Repository

    Yates, Matthew D.; Cusick, Roland D.; Ivanov, Ivan; Logan, Bruce E.

    2014-01-01

    © 2014 Wiley Periodicals, Inc. Actively respiring biofilms of Geobacter sulfurreducens were used as a biotemplate to form a palladium mesoporous layer directly on an electrode surface. Cells and proteins within the biofilm acted as the reductant and stabilizer to facilitate the reduction, dispersion, and attachment of palladium nanoparticles to the electrode surface without using synthetic chemicals. © 2014 Wiley Periodicals, Inc. Mesoporous structures can increase catalytic activity by maximizing the ratio of surface area to volume, but current synthesis techniques utilize expensive polymers and toxic chemicals. A Geobacter sulfurreducens biofilm was used as a sustainable template to form mesoporous Pd structures while eliminating the need for synthetic chemicals. The bulk of the biofilm material was removed by thermal treatments after nanoparticle formation, producing a catalytic Pd mesoporous (pore size 9.7±0.1nm) structure attached to the graphite electrode with a 1.5-2μm thick backbone composed of nanoparticles (~200nm). A control electrode electrochemically plated with Pd in the absence of a biofilm exhibited a variable planar Pd base (~0.5-3μm thick) with sporadic Pd extrusions (~2μm across, 1-5μm tall) from the surface. The biotemplated mesoporous structure produced 15-20% higher stable current densities during H2 oxidation tests than the electrochemically plated control electrode, even though 30% less Pd was present in the biotemplated catalyst. These results indicate that electroactive biofilms can be used as a sustainable base material to produce nanoporous structures without the need for synthetic polymers. Biotechnol. Bioeng. 2014;111: 2349-2354.

  19. Charge transport in metal oxide nanocrystal-based materials

    Science.gov (United States)

    Runnerstrom, Evan Lars

    There is probably no class of materials more varied, more widely used, or more ubiquitous than metal oxides. Depending on their composition, metal oxides can exhibit almost any number of properties. Of particular interest are the ways in which charge is transported in metal oxides: devices such as displays, touch screens, and smart windows rely on the ability of certain metal oxides to conduct electricity while maintaining visible transparency. Smart windows, fuel cells, and other electrochemical devices additionally rely on efficient transport of ionic charge in and around metal oxides. Colloidal synthesis has enabled metal oxide nanocrystals to emerge as a relatively new but highly tunable class of materials. Certain metal oxide nanocrystals, particularly highly doped metal oxides, have been enjoying rapid development in the last decade. As in myriad other materials systems, structure dictates the properties of metal oxide nanocrystals, but a full understanding of how nanocrystal synthesis, the processing of nanocrystal-based materials, and the structure of nanocrystals relate to the resulting properties of nanocrystal-based materials is still nascent. Gaining a fundamental understanding of and control over these structure-property relationships is crucial to developing a holistic understanding of metal oxide nanocrystals. The unique ability to tune metal oxide nanocrystals by changing composition through the introduction of dopants or by changing size and shape affords a way to study the interplay between structure, processing, and properties. This overall goal of this work is to chemically synthesize colloidal metal oxide nanocrystals, process them into useful materials, characterize charge transport in materials based on colloidal metal oxide nanocrystals, and develop ways to manipulate charge transport. In particular, this dissertation characterizes how the charge transport properties of metal oxide nanocrystal-based materials depend on their processing and

  20. Glass material oxidation and dissolution system: Converting miscellaneous fissile materials to glass

    International Nuclear Information System (INIS)

    Forsberg, C.W.; Ferrada, J.J.

    1996-01-01

    The cold war and the development of nuclear energy have resulted in significant inventories of miscellaneous fissile materials (MFMs). MFMs include (1) plutonium scrap and residue, (2) miscellaneous spent nuclear fuel (SNF), (3) certain hot cell wastes, and (4) many one-of-a-kind materials. Major concerns associated with the long-term management of these materials include: safeguards and nonproliferation issues; health, environment, and safety concerns. waste management requirements; and high storage costs. These issues can be addressed by converting the MFMs to glass for secure, long-term storage or repository disposal; however, conventional glass-making processes require oxide-like feed materials. Converting MFMs to oxide-like materials with subsequent vitrification is a complex and expensive process. A new vitrification process has been invented, the Glass Material Oxidation and Dissolution System (GMODS), which directly converts metals, ceramics, and amorphous solids to glass; oxidizes organics with the residue converted to glass; and converts chlorides to borosilicate glass and a secondary sodium chloride (NaCl) stream. Laboratory work has demonstrated the conversion of cerium (a plutonium surrogate), uranium, Zircaloy, stainless steel, multiple oxides, and other materials to glass. However, significant work is required to develop GMODS further for applications at an industrial scale. If implemented, GMODS will provide a new approach to manage these materials

  1. Translucency and Strength of High-Translucency Monolithic Zirconium-Oxide Materials

    Science.gov (United States)

    2016-05-12

    Capt Todd D. Church APPROVED: Translucency and Strength of High-Translucency Monolithic Zirconium -Oxide Materials C~t) Kraig/[ Vandewalle Date...copyrighted material in the thesis/dissertation manuscript entitled: "Translucency arid Strength of High-Translucency Monolithic Zirconium -Oxide...Translucency Monolithic Zirconium -Oxide Materials Abstract Dental materials manufacturers have developed more translucent monolithic zirconium oxide

  2. Mesoporous CdS via Network of Self-Assembled Nanocrystals: Synthesis, Characterization and Enhanced Photoconducting Property.

    Science.gov (United States)

    Patra, Astam K; Banerjee, Biplab; Bhaumik, Asim

    2018-01-01

    Semiconduction nanoparticles are intensively studied due to their huge potential in optoelctronic applications. Here we report an efficient chemical route for hydrothermal synthesis of aggregated mesoporous cadmium sulfide (CdS) nanoparticles using supramolecular-assembly of ionic and water soluble sodium salicylate as the capping agent. The nanostructure, mesophase, optical property and photoconductivity of these mesoporous CdS materials have been characterized by using small and wide angle powder X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), N2-sorption, Raman analysis, Fourier transformed infrared (FT-IR), UV-Visible DSR spectroscopy, and photoconductivity measurement. Wide angle XRD pattern and high resolution TEM image analysis suggested that the particle size of the materials is within 10 nm and the nanoparticles are in well-crystallized cubic phase. Mesoporous CdS nanoparticles showed drastically enhanced photoelectrochemical response under visible light irradiation on entrapping a photosensitizer (dye) molecule in the interparticle spaces. Efficient synthesis strategy and the enhanced photo response in the mesoporous CdS material could facilitate the designing of other porous semiconductor oxide/sulfide and their applications in photon-to-electron conversion processes.

  3. New Oxide Materials for an Ultra High Temperature Environment

    Energy Technology Data Exchange (ETDEWEB)

    Perepezko, John H. [Univ. of Wisconsin, Madison, WI (United States). Dept. of Materials Science and Engineering

    2017-11-13

    In this project, a new oxide material, Hf6Ta2O17 has been successfully synthesized by the controlled oxidization of Hf-Ta alloys. This oxide exhibits good oxidation resistance, high temperature phase stability up to more than 2000°C, low thermal conductivity and thus could serve as a component or a coating material in an ultrahigh temperature environment. We have examined the microstructure evolution and phase formation sequence during the oxidation exposure of Hf-Ta alloys at 1500°C and identified that the oxidation of a Hf-26.7atomic %Ta alloy leads to the formation of a single phase adherent Hf6Ta2O17 with a complex atomic structure i.e. superstructure. The overall reactive diffusion pathway is consistent with the calculated Hf-Ta-O ternary phase diagram. Besides the synthesis of Hf6Ta2O17 superstructure by oxidizing Hf-Ta alloys, we have also developed a synthesis method based upon the reactive sintering of the correct ratios of mixed powders of HfO2 and Ta2O5 and verified the low thermal conductivity of Hf6Ta2O17 superstructure on these samples. We have completed a preliminary analysis of the oxidation kinetics for Hf6Ta2O17, which shows an initial parabolic oxidation kinetics.

  4. 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.

  5. 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.

  6. Electrochemistry and determination of epinephrine using a mesoporous Al-incorporated SiO{sub 2} modified electrode

    Energy Technology Data Exchange (ETDEWEB)

    Zeng, Yanhong; Yang, Jinquan; Wu, Kangbing [Department of Chemistry, Huazhong University of Science and Technology, Wuhan 430074 (China)

    2008-05-30

    The potential application of Al-incorporated mesoporous SiO{sub 2} (denoted as Al-MCM-41) in electrochemistry as a novel electrode material was investigated. The peak currents of K{sub 3}[Fe(CN){sub 6}] remarkably increase and the peak potential separation obviously decreases at the mesoporous Al-MCM-41 modified carbon paste electrode (CPE). These phenomena suggest that the mesoporous Al-MCM-41 modified CPE possesses larger electrode area and electron transfer rate constant. Furthermore, the electrochemical behavior of epinephrine (EP) was investigated in different supporting electrolytes such as 0.01 mol L{sup -1} HClO{sub 4} and pH 7.0 phosphate buffer. It is found that the mesoporous Al-MCM-41 modified CPE exhibits catalytic ability to the oxidation of EP due to remarkable peak current enhancement and negative shift of peak potential. The electrochemical oxidation mechanism was also discussed. Finally, a novel electrochemical method was proposed for the determination of EP, which used to determine EP in urine samples. (author)

  7. Electrochemistry and determination of epinephrine using a mesoporous Al-incorporated SiO{sub 2} modified electrode

    Energy Technology Data Exchange (ETDEWEB)

    Zeng Yanhong; Yang Jinquan [Department of Chemistry, Huazhong University of Science and Technology, Wuhan 430074 (China); Wu Kangbing [Department of Chemistry, Huazhong University of Science and Technology, Wuhan 430074 (China)], E-mail: kbwu@mail.hust.edu.cn

    2008-05-30

    The potential application of Al-incorporated mesoporous SiO{sub 2} (denoted as Al-MCM-41) in electrochemistry as a novel electrode material was investigated. The peak currents of K{sub 3}[Fe(CN){sub 6}] remarkably increase and the peak potential separation obviously decreases at the mesoporous Al-MCM-41 modified carbon paste electrode (CPE). These phenomena suggest that the mesoporous Al-MCM-41 modified CPE possesses larger electrode area and electron transfer rate constant. Furthermore, the electrochemical behavior of epinephrine (EP) was investigated in different supporting electrolytes such as 0.01 mol L{sup -1} HClO{sub 4} and pH 7.0 phosphate buffer. It is found that the mesoporous Al-MCM-41 modified CPE exhibits catalytic ability to the oxidation of EP due to remarkable peak current enhancement and negative shift of peak potential. The electrochemical oxidation mechanism was also discussed. Finally, a novel electrochemical method was proposed for the determination of EP, which used to determine EP in urine samples.

  8. Towards deriving Ni-rich cathode and oxide-based anode materials from hydroxides by sharing a facile co-precipitation method.

    Science.gov (United States)

    Qiu, Haifa; Du, Tengfei; Wu, Junfeng; Wang, Yonglong; Liu, Jian; Ye, Shihai; Liu, Sheng

    2018-05-22

    Although intensive studies have been conducted on layered transition metal oxide(TMO)-based cathode materials and metal oxide-based anode materials for Li-ion batteries, their precursors generally follow different or even complex synthesis routes. To share one route for preparing precursors of the cathode and anode materials, herein, we demonstrate a facile co-precipitation method to fabricate Ni-rich hydroxide precursors of Ni0.8Co0.1Mn0.1(OH)2. Ni-rich layered oxide of LiNi0.8Co0.1Mn0.1O2 is obtained by lithiation of the precursor in air. An NiO-based anode material is prepared by calcining the precursor or multi-walled carbon nanotubes (MWCNTs) incorporated precursors. The pre-addition of ammonia solution can simplify the co-precipitation procedures and the use of an air atmosphere can also make the heat treatment facile. LiNi0.8Co0.1Mn0.1O2 as the cathode material delivers a reversible capacity of 194 mA h g-1 at 40 mA g-1 and a notable cycling retention of 88.8% after 100 cycles at 200 mA g-1. This noticeable performance of the cathode arises from a decent particle morphology and high crystallinity of the layered oxides. As the anode material, the MWCNTs-incorporated oxides deliver a much higher reversible capacity of 811.1 mA h g-1 after 200 cycles compared to the pristine oxides without MWCNTs. The improvement on electrochemical performance can be attributed to synergistic effects from MWCNTs incorporation, including reinforced electronic conductivity, rich meso-pores and an alleviated volume effect. This facile and sharing method may offer an integrated and economical approach for commercial production of Ni-rich electrode materials for Li-ion batteries.

  9. Effect of Gold Dispersion on the Photocatalytic Activity of Mesoporous Titania for the Vapor-Phase Oxidation of Acetone

    Directory of Open Access Journals (Sweden)

    S. V. Awate

    2008-01-01

    Full Text Available Mesostructured titanium dioxide photocatalyst, having uniform crystallite size (6–12 nm and average pore diameter of ∼4.2 nm, was synthesized by using a low-temperature nonsurfactant hydrothermal route, employing tartaric acid as a templating agent. Gold additions from 0.5 to 2 wt% were incorporated, either during the hydrothermal process or by postsynthesis wet impregnation. Compared to the impregnation-prepared samples, the samples synthesized hydrothermally contained smaller-size (≤1 nm gold clusters occluded in the pores of the host matrix. Whereas CO2 and H2O were the main reaction products in UV-assisted vapor-phase oxidation of acetone using these catalysts, C2H6 and HCO2CH3 were also produced for higher acetone concentrations in air. The conversion of acetone was found to increase with decrease in the size of both TiO2 and gold particles. In situ IR spectroscopy revealed that titania and gold particles serve as independent adsorption and reaction sites for acetone and oxygen molecules. Acetone molecules adsorb exclusively at TiO2 surface, giving rise to a strongly adsorbed (condensed state as well as to the formation of formate- and methyl formate-type surface species. Hydroxyl groups at titania surface participate directly in these adsorption steps. Nanosize gold particles, on the other hand, were primarily responsible for the adsorption and activation of oxygen molecules. Mechanistic aspects of the photochemical processes are discussed on the basis of these observations.

  10. Heavy metal oxide glasses as gamma rays shielding material

    International Nuclear Information System (INIS)

    Kaur, Preet; Singh, Devinder; Singh, Tejbir

    2016-01-01

    The gamma rays shielding parameters for heavy metal oxide glasses and concrete samples are comparable. However, the transparent nature of glasses provides additional feature to visualize inside the shielding material. Hence, different researchers had contributed in computing/measuring different shielding parameters for different configurations of heavy metal oxide glass systems. In the present work, a detailed study on different heavy metal (_5_6Ba, _6_4Gd, _8_2Pb, _8_3Bi) oxide glasses has been presented on the basis of different gamma rays shielding parameters as reported by different researchers in the recent years. It has been observed that among the selected heavy metal oxide glass systems, Bismuth based glasses provide better gamma rays shielding. Hence, Bismuth based glasses can be better substitute to concrete walls at nuclear reactor sites and nuclear labs.

  11. Heavy metal oxide glasses as gamma rays shielding material

    Energy Technology Data Exchange (ETDEWEB)

    Kaur, Preet; Singh, Devinder; Singh, Tejbir, E-mail: dr.tejbir@gmail.com

    2016-10-15

    The gamma rays shielding parameters for heavy metal oxide glasses and concrete samples are comparable. However, the transparent nature of glasses provides additional feature to visualize inside the shielding material. Hence, different researchers had contributed in computing/measuring different shielding parameters for different configurations of heavy metal oxide glass systems. In the present work, a detailed study on different heavy metal ({sub 56}Ba, {sub 64}Gd, {sub 82}Pb, {sub 83}Bi) oxide glasses has been presented on the basis of different gamma rays shielding parameters as reported by different researchers in the recent years. It has been observed that among the selected heavy metal oxide glass systems, Bismuth based glasses provide better gamma rays shielding. Hence, Bismuth based glasses can be better substitute to concrete walls at nuclear reactor sites and nuclear labs.

  12. Development and Processing of p-type Oxide Thermoelectric Materials

    DEFF Research Database (Denmark)

    Wu, NingYu; Van Nong, Ngo

    The main aim of this research is to investigate and develop well-performing p-type thermoelectric oxide materials that are sufficiently stable at high temperatures for power generating applications involving industrial processes. Presently, the challenges facing the widespread implementation...

  13. Materials and coatings to resist high temperature oxidation and corrosion

    International Nuclear Information System (INIS)

    1977-01-01

    Object of the given papers are the oxidation and corrosion behaviour of several materials (such as stainless steels, iron-, or nickel-, or cobalt-base alloys, Si-based ceramics) used at high temperatures and various investigations on high-temperature protective coatings. (IHoe) [de

  14. Dissolution of uranium oxide materials in simulated lung fluid

    International Nuclear Information System (INIS)

    Scripsick, R.C.; Soderholm, S.C.

    1985-01-01

    Depleted uranium (DU) oxide aerosols prepared in the laboratory and collected in the field were tested to characterize their dissolution in simulated lung fluid and to determine how dissolution is affected by aerosol preparation. DU, a by-product of the uranium fuel cycle, has been selected by the US military for use in several types of munitions. During development, manufacture, testing, and use of these munitions, opportunities exist for inhalation exposure to various (usually oxide) aerosol forms of DU. The hazard potential associated with such exposures is closely related to the chemical form, the size of the DU aerosol material, and its dissolution properties. Five DU sample materials produced by exposing uranium alloy penetrators to certain controlled oxidation atmospheres were studied (oxidation temperatures ranged from 500 to 900 0 C). In addition, two DU sample materials collected in the field were provided by the US Air Force. All sample materials were generated as aerosols and the respirable fraction was separated and collected. Data suggest that under some conditions a rapidly dissolving U 3 O 8 fraction may be formed concurrent with the production of UO 2

  15. Sol–gel one-pot synthesis in soft conditions of mesoporous silica materials ready for drug delivery system

    NARCIS (Netherlands)

    Tourne-Peteilh, C.; Begu, S.; Lerner, D.A.; Galarneau, A.; Lafont, U.; Devoiselle, J.M.

    2011-01-01

    The present work reveals a new and simple strategy, a one-step sol–gel procedure, to encapsulate a low water-soluble drug in silica mesostructured microparticles and to improve its release in physiological media. The synthesis of these new materials is based on the efficient solubilisation of a

  16. Acidic and catalytic properties of hierarchical zeolites and hybrid ordered mesoporous materials assembled from MFI protozeolitic units

    Czech Academy of Sciences Publication Activity Database

    Serrano, D. P.; García, R. A.; Vicente, G.; Linares, M.; Vitvarová, Dana; Čejka, Jiří

    2011-01-01

    Roč. 279, č. 2 (2011), s. 366-380 ISSN 0021-9517 Institutional research plan: CEZ:AV0Z40400503 Keywords : hierarchical zeolites * hybrid zeolitic-mesostructured materials * Bronsted and Lewis acid centres Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 6.002, year: 2011

  17. Machine-learned and codified synthesis parameters of oxide materials

    Science.gov (United States)

    Kim, Edward; Huang, Kevin; Tomala, Alex; Matthews, Sara; Strubell, Emma; Saunders, Adam; McCallum, Andrew; Olivetti, Elsa

    2017-09-01

    Predictive materials design has rapidly accelerated in recent years with the advent of large-scale resources, such as materials structure and property databases generated by ab initio computations. In the absence of analogous ab initio frameworks for materials synthesis, high-throughput and machine learning techniques have recently been harnessed to generate synthesis strategies for select materials of interest. Still, a community-accessible, autonomously-compiled synthesis planning resource which spans across materials systems has not yet been developed. In this work, we present a collection of aggregated synthesis parameters computed using the text contained within over 640,000 journal articles using state-of-the-art natural language processing and machine learning techniques. We provide a dataset of synthesis parameters, compiled autonomously across 30 different oxide systems, in a format optimized for planning novel syntheses of materials.

  18. Direct access to mesoporous crystalline TiO2/carbon composites with large and uniform pores for use as anode materials in lithium ion batteries

    NARCIS (Netherlands)

    Lee, J.; Jung, Y.S.; Warren, S.C.; Kamperman, M.M.G.; Oh, S.M.; DiSalvo, F.J.; Wiesner, U.

    2011-01-01

    Mesoporous and highly crystalline TiO2 (anatase)/carbon composites with large (>5¿nm) and uniform pores were synthesized using PI-b-PEO block copolymers as structure directing agents. Pore sizes could be tuned by utilizing block copolymers with different molecular weights. The resulting

  19. Cyclic catalytic upgrading of chemical species using metal oxide materials

    Science.gov (United States)

    White, James H; Schutte, Erick J; Rolfe, Sara L

    2013-05-07

    Processes are disclosure which comprise alternately contacting an oxygen-carrying catalyst with a reducing substance, or a lower partial pressure of an oxidizing gas, and then with the oxidizing gas or a higher partial pressure of the oxidizing gas, whereby the catalyst is alternately reduced and then regenerated to an oxygenated state. In certain embodiments, the oxygen-carrying catalyst comprises at least one metal oxide-containing material containing a composition having the following formulas: (a) Ce.sub.xB.sub.yB'.sub.zB''O.sub..delta., wherein B=Ba, Sr, Ca, or Zr; B'=Mn, Co, and/or Fe; B''=Cu; 0.01Ba, Ca, La, or K; 0.02material itself or as a support for said unary or binary metal oxides.

  20. Crystalline mesoporous zirconia catalysts having stable tetragonal pore wall structure

    Science.gov (United States)

    Sachtler, W.M.H.; Huang, Y.Y.

    1998-07-28

    Methods are disclosed for the preparation of new sulfated mesoporous zirconia materials/catalysts with crystalline pore walls of predominantly tetragonal crystal structure, characterized by nitrogen physical sorption measurement, X-ray diffraction, transmission electron microscopy and catalytic tests using n-butane isomerization to iso-butane and alkylation of 1-naphthol with 4-tert-butylstyrene as probe reactions. Sulfate deposition is preferred for the transformation of a mesoporous precursor with amorphous pore walls into a material with crystalline pore walls maintaining the mesoporous characteristics. 17 figs.

  1. Tunable Mesoporous Bragg Reflectors Based on Block-Copolymer Self-Assembly

    KAUST Repository

    Guldin, Stefan; Kolle, Mathias; Stefik, Morgan; Langford, Richard; Eder, Dominik; Wiesner, Ulrich; Steiner, Ullrich

    2011-01-01

    Mesoporous Bragg reflectors are a promising materials platform for photovoltaics, light emission, and sensing. A fast and versatile fabrication route that relies on the self-assembly of the block copolymer poly(isoprene-b-ethylene oxide) in combination with simple sol-gel chemistry is reported. The method allows extended control over porosity and pore size in the resulting inorganic material and results in high-quality optical elements. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Tunable Mesoporous Bragg Reflectors Based on Block-Copolymer Self-Assembly

    KAUST Repository

    Guldin, Stefan

    2011-07-06

    Mesoporous Bragg reflectors are a promising materials platform for photovoltaics, light emission, and sensing. A fast and versatile fabrication route that relies on the self-assembly of the block copolymer poly(isoprene-b-ethylene oxide) in combination with simple sol-gel chemistry is reported. The method allows extended control over porosity and pore size in the resulting inorganic material and results in high-quality optical elements. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Preparation of Reduced Graphene Oxides as Electrode Materials for Supercapacitors

    KAUST Repository

    Bai, Yaocai

    2012-06-01

    Reduced graphene oxide as outstanding candidate electrode material for supercapacitor has been investigated. This thesis includes two topics. One is that three kinds of reduced graphene oxides were prepared by hydrothermal reduction under different pH conditions. The pH values were found to have great influence on the reduction of graphene oxides. Acidic and neutral media yielded reduced graphene oxides with more oxygen-functional groups, lower specific surface areas but broader pore size distributions than those in basic medium. Variations induced by the pH changes resulted in great differences in the supercapacitor performance. The graphene produced in the basic solution presented mainly electric double layer behavior with specific capacitance of 185 F/g, while the other two showed additional pseudocapacitance behavior with specific capacitance of 225 F/g (acidic) and 230 F/g (neutral), all at a constant current density of 1A/g. The other one is that different reduced graphene oxides were prepared via solution based hydrazine reduction, low temperature thermal reduction, and hydrothermal reduction. The as- prepared samples were then investigated by UV-vis spectroscopy, X-ray diffraction, Raman spectroscopy, and Scanning electron microscope. The supercapacitor performances were also studied and the hydrothermally reduced graphene oxide exhibited the highest specific capacitance.

  4. Vanadium Doped Tungsten Oxide Material - Electrical Physical and Sensing Properties

    Directory of Open Access Journals (Sweden)

    Shishkin N. Y.

    2008-05-01

    Full Text Available The electrical physical and sensing (to VOCs and inorganic gases properties of vanadium doped tungsten oxide in the regions of phase transition temperature were investigated. Vanadium oxide (II dimerization was observed in the doped material, corresponding to new phase transition. The extreme sensitivity and selectivity to chemically active gases and vapors in small concentrations: CO, NOx, NH3 acetone, ethanol near phase transitions temperature was found. Sensor elements were manufactured for the quantitative detection (close to 1 ppm of alcohol and ammonia.

  5. 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.

  6. Mesoporous nanocrystalline film architecture for capacitive storage devices

    Science.gov (United States)

    Dunn, Bruce S.; Tolbert, Sarah H.; Wang, John; Brezesinski, Torsten; Gruner, George

    2017-05-16

    A mesoporous, nanocrystalline, metal oxide construct particularly suited for capacitive energy storage that has an architecture with short diffusion path lengths and large surface areas and a method for production are provided. Energy density is substantially increased without compromising the capacitive charge storage kinetics and electrode demonstrates long term cycling stability. Charge storage devices with electrodes using the construct can use three different charge storage mechanisms immersed in an electrolyte: (1) cations can be stored in a thin double layer at the electrode/electrolyte interface (non-faradaic mechanism); (2) cations can interact with the bulk of an electroactive material which then undergoes a redox reaction or phase change, as in conventional batteries (faradaic mechanism); or (3) cations can electrochemically adsorb onto the surface of a material through charge transfer processes (faradaic mechanism).

  7. Flexible anodized aluminum oxide membranes with customizable back contact materials.

    Science.gov (United States)

    Nadimpally, B; Jarro, C A; Mangu, R; Rajaputra, S; Singh, V P

    2016-12-16

    Anodized aluminum oxide (AAO) membranes were fabricated using flexible substrate/carrier material. This method facilitates the use of AAO templates with many different materials as substrates that are otherwise incompatible with most anodization techniques. Thin titanium (Ti) and tungsten (W) layers were employed as interlayer materials. Titanium enhances adhesion. Tungsten not only helps eliminate the barrier layer but also plays a critical role in enabling the use of flexible substrates. The resulting flexible templates provide new, exciting opportunities in photovoltaic and other device applications. CuInSe 2 nanowires were electrochemically deposited into porous AAO templates with molybdenum (Mo) as the back contact material. The feasibility of using any material to form a contact with semiconductor nanowires has been demonstrated for the first time enabling new avenues in photovoltaic applications.

  8. Flexible anodized aluminum oxide membranes with customizable back contact materials

    Science.gov (United States)

    Nadimpally, B.; Jarro, C. A.; Mangu, R.; Rajaputra, S.; Singh, V. P.

    2016-12-01

    Anodized aluminum oxide (AAO) membranes were fabricated using flexible substrate/carrier material. This method facilitates the use of AAO templates with many different materials as substrates that are otherwise incompatible with most anodization techniques. Thin titanium (Ti) and tungsten (W) layers were employed as interlayer materials. Titanium enhances adhesion. Tungsten not only helps eliminate the barrier layer but also plays a critical role in enabling the use of flexible substrates. The resulting flexible templates provide new, exciting opportunities in photovoltaic and other device applications. CuInSe2 nanowires were electrochemically deposited into porous AAO templates with molybdenum (Mo) as the back contact material. The feasibility of using any material to form a contact with semiconductor nanowires has been demonstrated for the first time enabling new avenues in photovoltaic applications.

  9. Catalytic properties and acidity of modified MCM-41 mesoporous materials with low Si/Al ratio: heptane isomerisation

    Directory of Open Access Journals (Sweden)

    Ahmed Belhakem

    2006-06-01

    Full Text Available The catalytic properties and acidity of modified MCM-41 with a low Si/Al ratio and 0-95% NH4+ exchange were investigated. The samples were characterised by X-ray diffraction, scanning and transmission electron microscopy, and nitrogen adsorption. The acidity was studied by pyridine adsorption, temperature programmed desorption (TPD of ammonia, and infrared (IR spectroscopy. Adsorption of pyridine and IR spectroscopy indicated various types of Lewis and Brönsted acid sites. The density distribution of acid sites was determined by TPD. Both Lewis and Brönsted acid sites were found to be active in the heptane isomerisation. The presence of aluminium (low Si/Al combined to the ionic exchange between Na+ and NH4+ increases the acidity of MCM-41 materials. A close correlation between acidity and isomerisation was observed. Coke deposition, which reduces the activity, was also studied.

  10. Study of uranium oxidation states in geological material.

    Science.gov (United States)

    Pidchenko, I; Salminen-Paatero, S; Rothe, J; Suksi, J

    2013-10-01

    A wet chemical method to determine uranium (U) oxidation states in geological material has been developed and tested. The problem faced in oxidation state determinations with wet chemical methods is that U redox state may change when extracted from the sample material, thereby leading to erroneous results. In order to quantify and monitor U redox behavior during the acidic extraction in the procedure, an analysis of added isotopic redox tracers, (236)U(VI) and (232)U(IV), and of variations in natural uranium isotope ratio ((234)U/(238)U) of indigenous U(IV) and U(VI) fractions was performed. Two sample materials with varying redox activity, U bearing rock and U-rich clayey lignite sediment, were used for the tests. The Fe(II)/Fe(III) redox-pair of the mineral phases was postulated as a potentially disturbing redox agent. The impact of Fe(III) on U was studied by reducing Fe(III) with ascorbic acid, which was added to the extraction solution. We observed that ascorbic acid protected most of the U from oxidation. The measured (234)U/(238)U ratio in U(IV) and U(VI) fractions in the sediment samples provided a unique tool to quantify U oxidation caused by Fe(III). Annealing (sample heating) to temperatures above 500 °C was supposed to heal ionizing radiation induced defects in the material that can disturb U redox state during extraction. Good agreement between two independent methods was obtained for DL-1a material: an average 38% of U(IV) determined by redox tracer corrected wet chemistry and 45% for XANES. Copyright © 2013 Elsevier Ltd. All rights reserved.

  11. Graphene oxide as an optimal candidate material for methane storage.

    Science.gov (United States)

    Chouhan, Rajiv K; Ulman, Kanchan; Narasimhan, Shobhana

    2015-07-28

    Methane, the primary constituent of natural gas, binds too weakly to nanostructured carbons to meet the targets set for on-board vehicular storage to be viable. We show, using density functional theory calculations, that replacing graphene by graphene oxide increases the adsorption energy of methane by 50%. This enhancement is sufficient to achieve the optimal binding strength. In order to gain insight into the sources of this increased binding, that could also be used to formulate design principles for novel storage materials, we consider a sequence of model systems that progressively take us from graphene to graphene oxide. A careful analysis of the various contributions to the weak binding between the methane molecule and the graphene oxide shows that the enhancement has important contributions from London dispersion interactions as well as electrostatic interactions such as Debye interactions, aided by geometric curvature induced primarily by the presence of epoxy groups.

  12. Ruthenium oxide/carbon composites with microporous or mesoporous carbon as support and prepared by two procedures. A comparative study as supercapacitor electrodes

    International Nuclear Information System (INIS)

    Pico, F.; Morales, E.; Fernandez, J.A.; Centeno, T.A.; Ibanez, J.; Rojas, R.M.; Amarilla, J.M.; Rojo, J.M.

    2009-01-01

    Composites are prepared by deposition of nanoparticles of RuO 2 .xH 2 O (1-4 nm) on two carbons: microporous carbon (1.3 nm of average micropore size) and mesoporous carbon (11 nm of average mesopore size). Two-preparation procedures are used: (i) procedure A consisting of repetitive impregnations of the carbons with RuCl 3 .0.5H 2 O solutions, and (ii) procedure B based on impregnation of the carbons with Ru(acac) 3 vapour. The procedure B leads to supported RuO 2 .xH 2 O particles that appear more crystalline than those obtained by the procedure A. Specific capacitance and specific surface area of the composites are discussed as functions of the RuO 2 content, and different dependences for the composites derived from the two carbons are found. Mesoporous carbon is better support than microporous carbon. Procedure A leads to supported RuO 2 .xH 2 O particles with higher specific capacitance than the particles deposited by procedure B

  13. Ruthenium oxide/carbon composites with microporous or mesoporous carbon as support and prepared by two procedures. A comparative study as supercapacitor electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Pico, F. [Instituto de Ciencia de Materiales de Madrid (ICMM), Consejo Superior de Investigaciones Cientificas (CSIC), Sor Juana Ines de la Cruz 3, Cantoblanco, E-28049-Madrid (Spain); Morales, E. [Instituto de Ciencia y Tecnologia de Polimeros (ICTP), CSIC, Juan de la Cierva 3, E-28006-Madrid (Spain); Fernandez, J.A.; Centeno, T.A. [Instituto Nacional del Carbon (INCAR), CSIC, Francisco Pintado Fe 26, E-33011-Oviedo (Spain); Ibanez, J. [Centro Nacional de Investigaciones Metalurgicas (CENIM), CSIC, Avda. Gregorio del Amo 8, E-28040-Madrid (Spain); Rojas, R.M.; Amarilla, J.M. [Instituto de Ciencia de Materiales de Madrid (ICMM), Consejo Superior de Investigaciones Cientificas (CSIC), Sor Juana Ines de la Cruz 3, Cantoblanco, E-28049-Madrid (Spain); Rojo, J.M. [Instituto de Ciencia de Materiales de Madrid (ICMM), Consejo Superior de Investigaciones Cientificas (CSIC), Sor Juana Ines de la Cruz 3, Cantoblanco, E-28049-Madrid (Spain)], E-mail: jmrojo@icmm.csic.es

    2009-03-01

    Composites are prepared by deposition of nanoparticles of RuO{sub 2}.xH{sub 2}O (1-4 nm) on two carbons: microporous carbon (1.3 nm of average micropore size) and mesoporous carbon (11 nm of average mesopore size). Two-preparation procedures are used: (i) procedure A consisting of repetitive impregnations of the carbons with RuCl{sub 3}.0.5H{sub 2}O solutions, and (ii) procedure B based on impregnation of the carbons with Ru(acac){sub 3} vapour. The procedure B leads to supported RuO{sub 2}.xH{sub 2}O particles that appear more crystalline than those obtained by the procedure A. Specific capacitance and specific surface area of the composites are discussed as functions of the RuO{sub 2} content, and different dependences for the composites derived from the two carbons are found. Mesoporous carbon is better support than microporous carbon. Procedure A leads to supported RuO{sub 2}.xH{sub 2}O particles with higher specific capacitance than the particles deposited by procedure B.

  14. Surfactant-directed synthesis of mesoporous films made single-step by a tandem photosol-gel/photocalcination route

    Energy Technology Data Exchange (ETDEWEB)

    De Paz-Simon, Héloïse; Chemtob, Abraham, E-mail: abraham.chemtob@uha.fr; Croutxé-Barghorn, Céline [Laboratory of Macromolecular Photochemistry and Engineering, ENSCMu, University of Haute-Alsace, 3 bis rue Alfred Werner, 68093 Mulhouse Cedex (France); Rigolet, Séverinne; Michelin, Laure; Vidal, Loïc; Lebeau, Bénédicte [Institut de Science des Matériaux de Mulhouse, UMR-CNRS 7361, University of Haute-Alsace, 3 rue Alfred Werner, 68093 Mulhouse Cedex (France)

    2014-11-01

    In view of their technological impact in materials chemistry, a simplified and more efficient synthetic route to mesoporous films is highly sought. We report, herein, a smart UV-mediated approach coupling in a one-stage process sol-gel photopolymerization and photoinduced template decomposition/ablation to making mesoporous silica films. Performed at room temperature with a solvent-free solution of silicate precursor and amphiphilic poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) block copolymer, the synthesis relies on photoacid generation to induce the fast formation (≈10 min) of mesostructured silica/surfactant domains. Continuation of UV exposure for three additional hours enables subsequent and complete photodegradation of the polyether copolymer, resulting in ordered or disordered mesoporous silica film. One of the most attractive features is that the one-step procedure relies on a continuous illumination provided by the same conventional medium-pressure Hg-Xe arc lamp equipped with a 254 nm reflector to enhance the emission of energetic photons <300 nm. In addition to X-ray diffraction and transmission electron microscopy, time-resolved Fourier transform infrared spectroscopy has proved to be a powerful in situ technique to probe the different chemical transformations accompanying irradiation. Photocalcination strengthens the inorganic network, while allowing to preserve a higher fraction of residual silanol groups compared with thermal calcination. A polyether chain degradation mechanism based on oxygen reactive species-mediated photo-oxidation is proposed.

  15. Apparatus and method for oxidation and stabilization of polymeric materials

    Science.gov (United States)

    Paulauskas, Felix L [Knoxville, TN; White, Terry L [Knoxville, TN; Sherman, Daniel M [Knoxville, TN

    2009-05-19

    An apparatus for treating polymeric materials comprises a treatment chamber adapted to maintain a selected atmosphere; a means for supporting the polymeric material within the chamber; and, a source of plasma-derived gas containing at least one reactive oxidative species whereby the polymer is stabilized and cross linked through exposure to the oxidative species in the chamber at a selected temperature. The polymer may be directly exposed to the plasma, or alternatively, the plasma may be established in a separate volume from which the reactive species may be extracted and introduced into the vicinity of the polymer. The apparatus may be configured for either batch-type or continuous-type processing. The apparatus and method are especially useful for preparing polymer fibers, particularly PAN fibers, for later carbonization treatments.

  16. Apparatus and method for stabilization or oxidation of polymeric materials

    Science.gov (United States)

    Paulauskas, Felix L [Knoxville, TN; Sherman, Daniel M [Knoxville, TN

    2010-01-19

    An apparatus for treating polymeric materials comprises a treatment chamber adapted to maintain a selected atmosphere at a selected temperature; a means for supporting the polymeric material within the chamber; and, a source of ozone-containing gas, which decomposes at the selected temperature yielding at least one reactive oxidative species whereby the polymer is stabilized and cross linked through exposure to the oxidative species in the chamber at the selected temperature. The ozone may be generated by a plasma discharge or by various chemical processes. The apparatus may be configured for either batch-type or continuous-type processing. The apparatus and method are especially useful for preparing polymer fibers, particularly PAN fibers, for later carbonization treatments as well as to make flame-retardant fabrics.

  17. Mesoporous yttria-zirconia and metal-yttria-zirconia solid solutions for fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Mamak, M.; Coombs, N.; Ozin, G. [Toronto Univ., ON (Canada). Dept. of Chemistry

    2000-02-03

    A new class of binary mesoporous yttria-zirconia (YZ) and ternary mesoporous metal-YZ materials (M = electroactive Ni/Pt) is presented here that displays the highest surface area of any known form of yttria-stabilized zirconia. These mesoporous materials form as solid solutions and retain their structural integrity to 800 C, which bodes well for their possible utilization in fuel cells. (orig.)

  18. Mesoporous silica formulation strategies for drug dissolution enhancement: a review.

    Science.gov (United States)

    McCarthy, Carol A; Ahern, Robert J; Dontireddy, Rakesh; Ryan, Katie B; Crean, Abina M

    2016-01-01

    Silica materials, in particular mesoporous silicas, have demonstrated excellent properties to enhance the oral bioavailability of poorly water-soluble drugs. Current research in this area is focused on investigating the kinetic profile of drug release from these carriers and manufacturing approaches to scale-up production for commercial manufacture. This review provides an overview of different methods utilized to load drugs onto mesoporous silica carriers. The influence of silica properties and silica pore architecture on drug loading and release are discussed. The kinetics of drug release from mesoporous silica systems is examined and the manufacturability and stability of these formulations are reviewed. Finally, the future prospects of mesoporous silica drug delivery systems are considered. Substantial progress has been made in the characterization and development of mesoporous drug delivery systems for drug dissolution enhancement. However, more research is required to fully understand the drug release kinetic profile from mesoporous silica materials. Incomplete drug release from the carrier and the possibility of drug re-adsorption onto the silica surface need to be investigated. Issues to be addressed include the manufacturability and regulation status of formulation approaches employing mesoporous silica to enhance drug dissolution. While more research is needed to support the move of this technology from the bench to a commercial medicinal product, it is a realistic prospect for the near future.

  19. 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.

  20. In situ synthesis, characterization, and catalytic performance of tungstophosphoric acid encapsulated into the framework of mesoporous silica pillared clay.

    Science.gov (United States)

    Li, Baoshan; Liu, Zhenxing; Han, Chunying; Ma, Wei; Zhao, Songjie

    2012-07-01

    Mesoporous silica pillared clay (SPC) incorporated with tungstophosphoric acid (HPW) has been synthesized via in situ introducing P and W source in the acidic suspension of the clay interlayer template during the formation of the silica pillared clay. The samples were characterized by XRD, XRF, FT-IR, TG-DTA, N(2) adsorption-desorption, and SEM techniques. The results showed that the HPW formed by in situ method has been effectively introduced into the framework of mesoporous silica pillared clay and its Keggin structure remained perfectly after formation of the materials. In addition, samples with similar HPW loadings were also prepared by impregnation method using SPC as the support. HPW in the incorporated samples was better dispersed into the silica pillared clay than in the impregnated samples. The results of catalytic tests indicated that the encapsulated materials demonstrated better catalytic performance than the impregnated samples in oxidative desulfurization (ODS) of dibenzothiophene (DBT). Copyright © 2012 Elsevier Inc. All rights reserved.

  1. Dual soft-template system based on colloidal chemistry for the synthesis of hollow mesoporous silica nanoparticles.

    Science.gov (United States)

    Li, Yunqi; Bastakoti, Bishnu Prasad; Imura, Masataka; Tang, Jing; Aldalbahi, Ali; Torad, Nagy L; Yamauchi, Yusuke

    2015-04-20

    A new dual soft-template system comprising the asymmetric triblock copolymer poly(styrene-b-2-vinyl pyridine-b-ethylene oxide) (PS-b-P2VP-b-PEO) and the cationic surfactant cetyltrimethylammonium bromide (CTAB) is used to synthesize hollow mesoporous silica (HMS) nanoparticles with a center void of around 17 nm. The stable PS-b-P2VP-b-PEO polymeric micelle serves as a template to form the hollow interior, while the CTAB surfactant serves as a template to form mesopores in the shells. The P2VP blocks on the polymeric micelles can interact with positively charged CTA(+) ions via negatively charged hydrolyzed silica species. Thus, dual soft-templates clearly have different roles for the preparation of the HMS nanoparticles. Interestingly, the thicknesses of the mesoporous shell are tunable by varying the amounts of TEOS and CTAB. This study provides new insight on the preparation of mesoporous materials based on colloidal chemistry. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Preparation of mesoporous NiO with a bimodal pore size distribution and application in electrochemical capacitors

    Energy Technology Data Exchange (ETDEWEB)

    Wang Dengchao; Ni Wenbin; Pang Huan; Lu Qingyi; Huang Zhongjie [Key Laboratory of Analytical Chemistry for Life Science (MOE), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210008 (China); Zhao Jianwei, E-mail: zhaojw@nju.edu.c [Key Laboratory of Analytical Chemistry for Life Science (MOE), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210008 (China)

    2010-09-01

    Mesoporous nickel oxide with a porous structure exhibiting a bimodal pore size distribution (2.6 and 30.3 nm diameter pores) has been synthesized in this paper. Firstly, a mesoporous precursor of coordination complex Ni{sub 3}(btc){sub 2}.12H{sub 2}O (btc = 1,3,5-benzenrtricarboxylic acid) is synthesized based on the metal-organic coordination mechanism by a hydrothermal method. Then mesoporous NiO with a bimodal size distribution is obtained by calcining the precursor in the air, and characterized by transmission electron microscopy and N{sub 2} adsorption measurements. Such unique multiple porous structure indicates a promising application of the obtained NiO as electrode materials for supercapacitors. The electrochemical behavior has been investigated by cyclic voltammogram, electrochemical impedance spectra and chronopotentiometry in 3 wt.% KOH aqueous electrolyte. The results reveal that the prepared NiO has high-capacitance retention at high scan rate and exhibits excellent cycle-life stability due to its special mesoporous character with bimodal size distribution.

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

    Energy Technology Data Exchange (ETDEWEB)

    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)

  4. O{sup -} bound small polarons in oxide materials

    Energy Technology Data Exchange (ETDEWEB)

    Schirmer, O F [Department of Physics, University of Osnabrueck, D-49076 Osnabrueck (Germany)

    2006-11-01

    Holes bound to acceptor defects in oxide crystals are often localized by lattice distortion at just one of the equivalent oxygen ligands of the defect. Such holes thus form small polarons in symmetric clusters of a few oxygen ions. An overview on mainly the optical manifestations of those clusters is given. The article is essentially divided into two parts: the first one covers the basic features of the phenomena and their explanations, exemplified by several paradigmatic defects; in the second part numerous oxide materials are presented which exhibit bound small polaron optical properties. The first part starts with summaries on the production of bound hole polarons and the identification of their structure. It is demonstrated why they show strong, wide absorption bands, usually visible, based on polaron stabilization energies of typically 1 eV. The basic absorption process is detailed with a fictitious two-well system. Clusters with four, six and twelve equivalent ions are realized in various oxide compounds. In these cases several degenerate optically excited polaron states occur, leading to characteristic final state resonance splittings. The peak energies of the absorption bands as well as the sign of the transfer energy depend on the topology of the clusters. A special section is devoted to the distinction between interpolaron and intrapolaron optical transitions. The latter are usually comparatively weak. The oxide compounds exhibiting bound hole small polaron absorptions include the alkaline earth oxides (e.g. MgO), BeO and ZnO, the perovskites BaTiO{sub 3} and KTaO{sub 3}, quartz, the sillenites (e.g. Bi{sub 12}TiO{sub 20}), Al{sub 2}O{sub 3}, LiNbO{sub 3}, topaz and various other materials. There are indications that the magnetic crystals NiO, doped with Li, and LaMnO{sub 3}, doped with Sr, also show optical features caused by bound hole polarons. Beyond being elementary paradigms for the properties of small polarons in general, the defect species treated

  5. Packaging material and flexible medical tubing containing thermally exfoliated graphite oxide

    Science.gov (United States)

    Prud'homme, Robert K. (Inventor); Aksay, Ilhan A. (Inventor)

    2011-01-01

    A packaging material or flexible medical tubing containing a modified graphite oxide material, which is a thermally exfoliated graphite oxide with a surface area of from about 300 m.sup.2/g to 2600 m.sup.2/g.

  6. Application of scandium oxide in an electron emission material

    International Nuclear Information System (INIS)

    Suqiu, Y.; Zhizheng, Z.; Yongde, W.

    1985-01-01

    Modern microwave devices impose a number of harsh requirements on the cathodes. For instance, they require cathodes having low working temperature, high emissive current density, slow evaporation rate of the emissive-active material, long lifetime, quick heating and so on. The commercial B-cathode is no longer able to meet these requirements completely. A scandate cathode may be a promising one for use in these devices. Adding rare-earth elements in the electron emission material has been reported in many papers. Based on a B-cathode we add a little amount of scandium oxide (about 3%) into emission material to manufacture a scandate cathode. The emission property of such a cathode has been improved greatly. If the composition is controlled correctly, the emission level of such a cathode may be five times more as high as the B-cathode

  7. Advanced manganese oxide material for rech