WorldWideScience

Sample records for nano porous carbon

  1. Cost-Effective Fabrication of Inner-Porous Micro/Nano Carbon Structures.

    Science.gov (United States)

    Jiang, Shulan; Shi, Tielin; Tang, Zirong; Xi, Shuang

    2018-03-01

    This paper reports the fabrication of a new micro/nano carbon architecture array which owns the characteristics of inner-porous, desired conductivity and large effective surface area. The micro/nano inner-porous carbon structures were fabricated for the first time, with ordinary and cost-effective processes, including photolithography, oxygen plasma etching and pyrolysis. Firstly, micro/nano hierarchical photoresist structures array was generated through photolithography and oxygen plasma etching processes. By introducing a critical thin-film spin-coating step, and followed with carefully pyrolyzing process, the micro/nano photoresist structures were converted into innerporous carbon architectures with good electric connection which connected the carbon structures array together. Probably the inner-porous property can be attributed to the shrinkage difference between positive thin film and negative photoresist structures during pyrolyzing process. It is demonstrated that the simple method is effective to fabricate inner-porous carbon structures with good electric connection and the carbon structures can be used as electrochemical electrodes directly and without the addition of other pyrolysis or film coating processes. The electrochemical property of the carbon structures has been explored by cyclic voltammetric measurement. Compared with solid carbon microstructures array, the cyclic voltammetry curve of inner-porous carbon structures shows greatly enhanced current and improved charge-storage capability, indicating great potential in micro energy storage devices and bio-devices.

  2. Porous Nano-Si/Carbon Derived from Zeolitic Imidazolate Frameworks@Nano-Si as Anode Materials for Lithium-Ion Batteries

    International Nuclear Information System (INIS)

    Song, Yonghai; Zuo, Li; Chen, Shouhui; Wu, Jiafeng; Hou, Haoqing; Wang, Li

    2015-01-01

    Graphical abstract: Display Omitted -- Highlights: •The porous cage-like carbon/Si nanocomposites were synthesized based on nano-Si@ZIF-8-templatedmethod. •The nano-Si was uniformly embedded in porous amorphous carbon matrices. •The porous dodecahedral carbon framework effectively accommodates the volume variation of Si during the discharge/charge process. •The Si/C nanocomposites exhibit superior reversible capacity of 1168 mA h g −1 after 100 cycles. -- Abstract: Novel porous cage-like carbon (C)/nano-Si nanocomposites as anode materials for lithium-ion batteries (LIBs) was prepared based on nano-Si@zeolitic imidazolate frameworks (ZIF-8)-templated method. In this strategy, p-aminobenzoic acid was initially grafted onto nano-Si to form benzoic acid-functionalized nano-Si, and then nano-Si@ZIF-8 was constructed by alternately growing Zn(NO 3 ) 2 ·6H 2 O and 2-methylimidazolate on benzoic acid-functionalized nano-Si under ultrasound. The novel porous cage-like nano-Si/C nanocomposites were fabricated by pyrolyzing the resulted nano-Si@ZIF-8 and washing with HCl to remove off ZnO. Scanning electron microscopy, transmission electron microscopy, X-ray powder diffraction, Raman spectra and N 2 adsorption/desorption isotherms were employed to characterize the porous cage-like nano-Si/C nanocomposites. The resulted nano-Si/C nanocomposites as anode materials for LIBs showed a high reversible capacity of ∼1168 mA h g −1 at 100 mA g −1 after 100 cycles, which was higher than many previously reported Si/C nanocomposites. The porous nanostructure, high specific surface area and good electrical conductivity of the cage-like nano-Si/C nanocomposites contributed together to the good performance for LIBs. It might open up a new way for application of silicon materials

  3. Direct electron transfer from glucose oxidase immobilized on a nano-porous glassy carbon electrode

    International Nuclear Information System (INIS)

    Haghighi, Behzad; Tabrizi, Mahmoud Amouzadeh

    2011-01-01

    Highlights: → A direct electron transfer reaction of glucose oxidase was observed on the surface of a nano-porous glassy carbon electrode. → A pair of well-defined and reversible redox peaks was observed at the formal potential of approximately -0.439 V. → The apparent electron transfer rate constant was measured to be 5.27 s -1 . → A mechanism for the observed direct electron transfer reaction was proposed, which consists of a two-electron and a two-proton transfer. - Abstract: A pair of well-defined and reversible redox peaks was observed for the direct electron transfer (DET) reaction of an immobilized glucose oxidase (GOx) on the surface of a nano-porous glassy carbon electrode at the formal potential (E o ') of -0.439 V versus Ag/AgCl/saturated KCl. The electron transfer rate constant (k s ) was calculated to be 5.27 s -1 . The dependence of E o ' on pH indicated that the direct electron transfer of the GOx was a two-electron transfer process, coupled with two-proton transfer. The results clearly demonstrate that the nano-porous glassy carbon electrode is a cost-effective and ready-to-use scaffold for the fabrication of a glucose biosensor.

  4. Direct electron transfer from glucose oxidase immobilized on a nano-porous glassy carbon electrode

    Energy Technology Data Exchange (ETDEWEB)

    Haghighi, Behzad, E-mail: haghighi@iasbs.ac.ir [Department of Chemistry, Institute for Advanced Studies in Basic Sciences, P.O. Box 45195-1159, Gava Zang, Zanjan (Iran, Islamic Republic of); Tabrizi, Mahmoud Amouzadeh [Department of Chemistry, Institute for Advanced Studies in Basic Sciences, P.O. Box 45195-1159, Gava Zang, Zanjan (Iran, Islamic Republic of)

    2011-11-30

    Highlights: > A direct electron transfer reaction of glucose oxidase was observed on the surface of a nano-porous glassy carbon electrode. > A pair of well-defined and reversible redox peaks was observed at the formal potential of approximately -0.439 V. > The apparent electron transfer rate constant was measured to be 5.27 s{sup -1}. > A mechanism for the observed direct electron transfer reaction was proposed, which consists of a two-electron and a two-proton transfer. - Abstract: A pair of well-defined and reversible redox peaks was observed for the direct electron transfer (DET) reaction of an immobilized glucose oxidase (GOx) on the surface of a nano-porous glassy carbon electrode at the formal potential (E{sup o}') of -0.439 V versus Ag/AgCl/saturated KCl. The electron transfer rate constant (k{sub s}) was calculated to be 5.27 s{sup -1}. The dependence of E{sup o}' on pH indicated that the direct electron transfer of the GOx was a two-electron transfer process, coupled with two-proton transfer. The results clearly demonstrate that the nano-porous glassy carbon electrode is a cost-effective and ready-to-use scaffold for the fabrication of a glucose biosensor.

  5. Nano-micro carbon spheres anchored on porous carbon derived from dual-biomass as high rate performance supercapacitor electrodes

    Science.gov (United States)

    Liu, Shaobo; Zhao, Yang; Zhang, Baihui; Xia, Hui; Zhou, Jianfei; Xie, Wenke; Li, Hongjian

    2018-03-01

    Hierarchical nano-micro carbon spheres@rice straw-derived porous carbon composites are successfully synthesized by the in situ decoration of the porous carbon with carbon spheres from glucose under the assistance of cetyltrimethyl ammonium bromide micelles and further activated by KOH. The scanning electron microscope images clearly show the carbon spheres disperse homogeneously and orderly onto the surface and in the inner macropores of the porous carbon. The diameter of the carbon spheres varies from 475 nm to 1.6 μm, which can be easily controlled by introducing extra inducing agent. The optimal composites exhibit a large specific surface area (1122 m2 g-1), rich content of oxygen (14.2 wt %), and tunable hierarchical porous structure. When used as supercapacitor electrodes, the novel composites with abundant fruits present a high specific capacitance of 337 F g-1 at 1 A g-1, excellent rate retention of 83% from 1 to 20 A g-1 and a good cycling stability with 96% capacitance retention after 10000 cycles. In this strategy, the thought of shared ion-buffering reservoirs is proposed and the mutual promotion effects between the carbon spheres and porous carbon in the composites are also practically demonstrated to contribute the enhanced electrochemical performances.

  6. Preparation by the nano-casting process of novel porous carbons from large pore zeolite templates

    International Nuclear Information System (INIS)

    F Gaslain; J Parmentier; V Valtchev; J Patarin; C Vix Guterl

    2005-01-01

    The development of new growing industrial applications such as gas storage (e.g.: methane or hydrogen) or electric double-layer capacitors has focussed the attention of many research groups. For this kind of application, porous carbons with finely tailored micro-porosity (i.e.: pore size diameter ≤ 1 nm) appear as very promising materials due to their high surface area and their specific pore size distribution. In order to meet these requirements, attention has been paid towards the feasibility of preparing microporous carbons by the nano-casting process. Since the sizes and shapes of the pores and walls respectively become the walls and pores of the resultant carbons, using templates with different framework topologies leads to various carbon replicas. The works performed with commercially available zeolites employed as templates [1-4] showed that the most promising candidate is the FAU-type zeolite, which is a large zeolite with three-dimensional channel system. The promising results obtained on FAU-type matrices encouraged us to study the microporous carbon formation on large pore zeolites synthesized in our laboratory, such as EMC-1 (International Zeolite Association framework type FAU), zeolite β (BEA) or EMC-2 (EMT). The carbon replicas were prepared following largely the nano-casting method proposed for zeolite Y by the Kyotani research group [4]: either by liquid impregnation of furfuryl alcohol (FA) followed by carbonization or by vapour deposition (CVD) of propylene, or by an association of these two processes. Heat treatment of the mixed materials (zeolite / carbon) could also follow in order to improve the structural ordering of the carbon. After removal of the inorganic template by an acidic treatment, the carbon materials obtained were characterised by several analytical techniques (XRD, N 2 and CO 2 adsorption, electron microscopy, etc...). The unique characteristics of these carbons are discussed in details in this paper and compared to those

  7. Effects of confinement in meso-porous silica and carbon nano-structures

    International Nuclear Information System (INIS)

    Leon, V.

    2006-07-01

    Physico-chemical properties of materials can be strongly modified by confinement because of the quantum effects that appear at such small length scales and also because of the effects of the confinement itself. The aim of this thesis is to show that both the nature of the confining material and the size of the pores and cavities have a strong impact on the confined material. We first show the effect of the pore size of the host meso-porous silica on the temperature of the solid-solid phase transition of silver selenide, a semiconducting material with enhanced magnetoresistive properties under non-stoichiometric conditions. Narrowing the pores from 20 nm to 2 nm raises the phase transition temperature from 139 C to 146 C. This result can be explained by considering the interaction between the confining and confined materials as a driving force. The effects of confinement are also studied in the case of hydrogen and deuterium inside cavities of organized carbon nano-structures. The effects that appear in the adsorption/desorption cycles are much stronger with carbon nano-horns as the host material than with C60 pea-pods and single-walled carbon nano-tubes. (author)

  8. Direct measurements of adsorption heats of hydrogen on nano-porous carbons

    International Nuclear Information System (INIS)

    Akihiko Matsumoto; Kazumasa Yamamoto; Tomoyuki Miyata

    2005-01-01

    Since a exciting report of hydrogen storage in single-walled carbon nano-tubes by Dillon and his colleagues, nano-porous carbon materials, such as carbon nano-tubes, carbon nano-horns and micro-porous activated carbon, have attracted considerable attention as hydrogen storage materials. Adsorption plays a predominating role in the hydrogen storage process on solid surfaces. The adsorption is a spontaneous process, which is caused by interaction between gas molecules and surface, hence, it is always exothermic process and observed as adsorption heats. For this reason, direct measurement of the adsorption heats by adsorption micro-calorimetry would provide quantitative information on the strength of adsorption interaction and the adsorption mechanism. However, the adsorption amounts of hydrogen on carbon materials are far less than those of condensable vapors near room temperature due to low critical temperature of hydrogen (33.2 K), therefore, the adsorption heats can not be determined accurately at conventional measurement conditions near room temperature and the atmospheric pressure. This contribution reports the calorimetric characterization of hydrogen adsorption on nano-porous carbon materials at low temperature and high-pressure conditions. The high-pressure adsorption apparatus consists of a volumetric adsorption line connected to a twin-conduction type microcalorimeter. Activated carbon fibers (ACF, Ad'all Co.) of different micro-pore sizes (Table 1) were used as model adsorbents. Each ACF has slit-shaped micropores of uniform size. The adsorption isotherms and differential heats of adsorption at high-pressure region from 0 to 10 MPa were simultaneously measured at isothermal condition from 203 to 298 K. The adsorption isotherms on ACF were of Henry type regardless of adsorption temperature and pore width; the uptakes increased linearly with equilibrium pressure. The adsorption isotherm at lower sorption temperature tended to show higher sorptivity. The

  9. Direct measurements of adsorption heats of hydrogen on nano-porous carbons

    International Nuclear Information System (INIS)

    Akihiko, Matsumoto; Kazumasa, Yamamoto; Tomoyuki, Miyata

    2005-01-01

    Since a exciting report of hydrogen storage in single-walled carbon nano-tubes by Dillon and his colleagues [1], nano-porous carbon materials, such as carbon nano-tubes, carbon nano-horns and micro-porous activated carbon, have attracted considerable attention as hydrogen storage materials. Adsorption plays a predominating role in the hydrogen storage process on solid surfaces. The adsorption is a spontaneous process, which is caused by interaction between gas molecules and surface, hence, it is always exothermic process and observed as adsorption heats. For this reason, direct measurement of the adsorption heats by adsorption microcalorimetry would provide quantitative information on the strength of adsorption interaction and the adsorption mechanism. However, the adsorption amounts of hydrogen on carbon materials are far less than those of condensable vapors near room temperature due to low critical temperature of hydrogen (33.2 K), therefore, the adsorption heats can not be determined accurately at conventional measurement conditions near room temperature and the atmospheric pressure. This contribution reports the calorimetric characterization of hydrogen adsorption on nano-porous carbon materials at low temperature and high-pressure conditions. The high-pressure adsorption apparatus consists of a volumetric adsorption line connected to a twin-conduction type microcalorimeter. Activated carbon fibers (ACF, Ad'all Co.) of different micropore sizes (Table 1) were used as model adsorbents. Each ACF has slit-shaped micropores of uniform size [2]. The adsorption isotherms and differential heats of adsorption at high-pressure region from 0 to 10 MPa were simultaneously measured at isothermal condition from 203 to 298 K. The adsorption isotherms on ACF were of Henry type regardless of adsorption temperature and pore width; the uptakes increased linearly with equilibrium pressure. The adsorption isotherm at lower sorption temperature tended to show higher sorptivity

  10. Porous carbons

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    Abstract. Carbon in dense as well as porous solid form is used in a variety of applications. Activated porous carbons are made through pyrolysis and activation of carbonaceous natural as well as synthetic precursors. Pyrolysed woods replicate the structure of original wood but as such possess very low surface areas and ...

  11. Hierarchical porous carbon materials prepared using nano-ZnO as a template and activation agent for ultrahigh power supercapacitors.

    Science.gov (United States)

    Wang, Haoran; Yu, Shukai; Xu, Bin

    2016-09-20

    Hierarchical porous carbon materials with high surface areas and a localized graphitic structure were simply prepared from sucrose using nano-ZnO as a hard template, activation agent and graphitization catalyst simultaneously, which exhibit an outstanding high-rate performance and can endure an ultrafast scan rate of 20 V s -1 and ultrahigh current density of 1000 A g -1 .

  12. Antithrombogenicity of Fluorinated Diamond-Like Carbon Films Coated Nano Porous Polyethersulfone (PES Membrane

    Directory of Open Access Journals (Sweden)

    Norihisa Miki

    2013-09-01

    Full Text Available A nano porous polyethersulfone (PES membrane is widely used for aspects of nanofiltration, such as purification, fractionation and dialysis. However, the low-blood-compatibility characteristic of PES membrane causes platelets and blood cells to stick to the surface of the membrane and degrades ions diffusion through membrane, which further limits its application for dialysis systems. In this study, we deposited the fluorinated-diamond-like-carbon (F-DLC onto the finger like structure layer of the PES membrane. By doing this, we have the F-DLC films coating the membrane surface without sacrificing the membrane permeability. In addition, we examined antithrombogenicity of the F-DLC/PES membranes using a microfluidic device, and experimentally found that F-DLC drastically reduced the amount of blood cells attached to the surface. We have also conducted long-term experiments for 24 days and the diffusion characteristics were found to be deteriorated due to fouling without any surface modification. On the other hand, the membranes coated by F-DLC film gave a consistent diffusion coefficient of ions transfer through a membrane porous. Therefore, F-DLC films can be a great candidate to improve the antithrombogenic characteristics of the membrane surfaces in hemodialysis systems.

  13. Antithrombogenicity of Fluorinated Diamond-Like Carbon Films Coated Nano Porous Polyethersulfone (PES) Membrane

    Science.gov (United States)

    Prihandana, Gunawan S.; Sanada, Ippei; Ito, Hikaru; Noborisaka, Mayui; Kanno, Yoshihiko; Suzuki, Tetsuya; Miki, Norihisa

    2013-01-01

    A nano porous polyethersulfone (PES) membrane is widely used for aspects of nanofiltration, such as purification, fractionation and dialysis. However, the low-blood-compatibility characteristic of PES membrane causes platelets and blood cells to stick to the surface of the membrane and degrades ions diffusion through membrane, which further limits its application for dialysis systems. In this study, we deposited the fluorinated-diamond-like-carbon (F-DLC) onto the finger like structure layer of the PES membrane. By doing this, we have the F-DLC films coating the membrane surface without sacrificing the membrane permeability. In addition, we examined antithrombogenicity of the F-DLC/PES membranes using a microfluidic device, and experimentally found that F-DLC drastically reduced the amount of blood cells attached to the surface. We have also conducted long-term experiments for 24 days and the diffusion characteristics were found to be deteriorated due to fouling without any surface modification. On the other hand, the membranes coated by F-DLC film gave a consistent diffusion coefficient of ions transfer through a membrane porous. Therefore, F-DLC films can be a great candidate to improve the antithrombogenic characteristics of the membrane surfaces in hemodialysis systems. PMID:28788333

  14. Migration of carbon dioxide included micro-nano bubble water in porous media and its monitoring

    Science.gov (United States)

    Takemura, T.; Hamamoto, S.; Suzuki, K.; Koichi, O.

    2017-12-01

    The distributed CO2 storage is the small scale storage and its located near the emission areas. In the distributed CO2 storage, the CO2 is neutralized by sediment and underground water in the subsurface region (300-500m depth). Carbon dioxide (CO2) included micro-nano bubbles is one approach in neutralizing CO2 and sediments by increasing CO2 volume per unit volume of water and accelerating the chemical reaction. In order to design underground treatment for CO2 gas in the subsurface, it is required to elucidate the behavior of CO2 included micro-nano bubbles in the water. In this study, we carried out laboratory experiment using the soil tank, and measure the amount of leakage of CO2 gas at the surface. In addition, the process of migration of carbon dioxide included micro-nano bubble was monitored by the nondestructive method, wave velocity and resistivity.

  15. Design and synthesis of porous nano-sized Sn@C/graphene electrode material with 3D carbon network for high-performance lithium-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Lian, Peichao, E-mail: lianpeichao@126.com [Faculty of Chemical Engineering, Kunming University of Science and Technology, Kunming 650500 (China); Wang, Jingyi [Faculty of Chemical Engineering, Kunming University of Science and Technology, Kunming 650500 (China); Cai, Dandan; Liu, Guoxue [School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510640 (China); Wang, Yingying [Faculty of Chemical Engineering, Kunming University of Science and Technology, Kunming 650500 (China); Wang, Haihui, E-mail: hhwang@scut.edu.cn [School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510640 (China)

    2014-08-01

    Highlights: • Porous nano-sized Sn@C/graphene electrode material was designed and prepared. • The preparation method presented here can avoid the agglomeration of nanoparticles. • The prepared Sn@C/graphene electrode material exhibits outstanding cyclability. - Abstract: Tin is a promising high-capacity anode material for lithium-ion batteries, but it usually suffers from the problem of poor cycling stability due to the large volume change during the charge–discharge process. In this article, porous nano-sized Sn@C/graphene electrode material with three-dimensional carbon network was designed and prepared. Reducing the size of the Sn particles to nanoscale can mitigate the absolute strain induced by the large volume change during lithiation–delithiation process, and retard particle pulverization. The porous structure can provide a void space, which helps to accommodate the volume changes of the Sn nanoparticles during the lithium uptake-release process. The carbon shell can avoid the aggregation of the Sn nanoparticles on the same piece of graphene and detachment of the pulverized Sn particles during the charge–discharge process. The 3D carbon network consisted of graphene sheets and carbon shells can not only play a structural buffering role in minimizing the mechanical stress caused by the volume change of Sn, but also keep the overall electrode highly conductive during the lithium uptake-release process. As a result, the as-prepared Sn@C/graphene nanocomposite as an anode material for lithium-ion batteries exhibited outstanding cyclability. The reversible specific capacity is almost constant from the tenth cycle to the fiftieth cycle, which is about 600 mA h g{sup −1}. The strategy presented in this work may be extended to improve the cycle performances of other high-capacity electrode materials with large volume variations during charge–discharge processes.

  16. Effects of confinement in meso-porous silica and carbon nano-structures; Etude des effets de confinement dans la silice mesoporeuse et dans certaines nanostructures carbonees

    Energy Technology Data Exchange (ETDEWEB)

    Leon, V

    2006-07-15

    Physico-chemical properties of materials can be strongly modified by confinement because of the quantum effects that appear at such small length scales and also because of the effects of the confinement itself. The aim of this thesis is to show that both the nature of the confining material and the size of the pores and cavities have a strong impact on the confined material. We first show the effect of the pore size of the host meso-porous silica on the temperature of the solid-solid phase transition of silver selenide, a semiconducting material with enhanced magnetoresistive properties under non-stoichiometric conditions. Narrowing the pores from 20 nm to 2 nm raises the phase transition temperature from 139 C to 146 C. This result can be explained by considering the interaction between the confining and confined materials as a driving force. The effects of confinement are also studied in the case of hydrogen and deuterium inside cavities of organized carbon nano-structures. The effects that appear in the adsorption/desorption cycles are much stronger with carbon nano-horns as the host material than with C60 pea-pods and single-walled carbon nano-tubes. (author)

  17. Nano/macro porous bioactive glass scaffold

    Science.gov (United States)

    Wang, Shaojie

    Bioactive glass (BG) and ceramics have been widely studied and developed as implants to replace hard tissues of the musculo-skeletal system, such as bones and teeth. Recently, instead of using bulk materials, which usually do not degrade rapidly enough and may remain in the human body for a long time, the idea of bioscaffold for tissue regeneration has generated much interest. An ideal bioscaffold is a porous material that would not only provide a three-dimensional structure for the regeneration of natural tissue, but also degrade gradually and, eventually be replaced by the natural tissue completely. Among various material choices the nano-macro dual porous BG appears as the most promising candidate for bioscaffold applications. Here macropores facilitate tissue growth while nanopores control degradation and enhance cell response. The surface area, which controls the degradation of scaffold can also be tuned by changing the nanopore size. However, fabrication of such 3D structure with desirable nano and macro pores has remained challenging. In this dissertation, sol-gel process combined with spinodal decomposition or polymer sponge replication method has been developed to fabricate the nano-macro porous BG scaffolds. Macropores up to 100microm are created by freezing polymer induced spinodal structure through sol-gel transition, while larger macropores (>200um) of predetermined size are obtained by the polymer sponge replication technique. The size of nanopores, which are inherent to the sol-gel method of glass fabrication, has been tailored using several approaches: Before gel point, small nanopores are generated using acid catalyst that leads to weakly-branched polymer-like network. On the other hand, larger nanopores are created with the base-catalyzed gel with highly-branched cluster-like structure. After the gel point, the nanostructure can be further modified by manipulating the sintering temperature and/or the ammonia concentration used in the solvent

  18. Embedding nano-Li{sub 4}Ti{sub 5}O{sub 12} in hierarchical porous carbon matrixes derived from water soluble polymers for ultra-fast lithium ion batteries anodic materials

    Energy Technology Data Exchange (ETDEWEB)

    Lan, Chun-Kai; Bao, Qi; Huang, Yao-Hui; Duh, Jenq-Gong, E-mail: jgd@mx.nthu.edu.tw

    2016-07-15

    Li{sub 4}Ti{sub 5}O{sub 12}/hierarchical porous carbon matrixes composites are successfully prepared by a facile and fast polymers assisted sol–gel method, aiming to promote both electronic and ionic conductivity. As indicated by Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy analysis, three less expensive cost and available water soluble polymers (e.g. PAA, CMC, and SA) can homogeneously react with Li–Ti–O precursor to incorporate into interior of nano-scale lithium titanate and provide a continues conductive network after pyrolysis. In addition, the results of scanning electron microscopy and transmission electron microscopy also prove that the Li{sub 4}Ti{sub 5}O{sub 12} nanoparticles are firmly embedded in porous carbon matrix with no obvious agglomeration. EIS measurement and cyclic voltammetry further reveal that the facilitated electrode kinetics and better ionic transport of Li{sub 4}Ti{sub 5}O{sub 12}/hierarchical porous carbon matrixes composites than that of Li{sub 4}Ti{sub 5}O{sub 12}. The c-CMC-LTO exhibits a superior capacity of 92 mAh g{sup −1} and retains its initial value with no obviously capacity decay over 200 cycles under an ultra-high C rate (50 C). - Graphical abstract: Schematic illustrations of the formation process of embedding LTO into Carbon matrixes derived from water soluable polymers (upper) and the electrochemical reaction paths in LTO/Carbon composites during charging/discharging processes (lower). - Highlights: • Hierarchical porous carbon matrixes were used to improve the Li{sub 4}Ti{sub 5}O{sub 12} anodes. • Carbon matrixes could suppress the agglomeration of Li{sub 4}Ti{sub 5}O{sub 12} nanoparticles. • meso-nanoporous carbon structure was beneficial for filtration of electrolyte. • The c-CMC-LTO exhibited superior high rate capability and cycling durability.

  19. Hydrogen adsorption in doped porous carbons

    International Nuclear Information System (INIS)

    Balan, L.; Duchaux, L.; Los, S.

    2005-01-01

    Full text of publication follows: Hydrogen is a clean fuel that will be used in automotive transport when the problem of storage will be solved. The difficulties of H 2 storage (available space, security and performance, etc...) require a material that can store 5 weight % of hydrogen. Research is focused on new materials that can assume the constraints imposed by the automotive applications. Among these materials, the nano-structured carbons (nano-fibers and single walled carbon nano-tubes) were claimed to be promising by numerous authors [1-3]. The more promising carbon materials for hydrogen adsorption are those having micropores (i. e. single walled carbon nano-tubes and activated carbon), for which the energy of sorption of hydrogen molecules is theoretically higher [7- 8]. Presently, the best performance of hydrogen adsorption was found in super-activated micro-porous carbons sorbing 5 weight % at 77 K, and almost 0.5 % at room temperature and 6 MPa [9]. Up to now, the performance of these materials can still be improved as the known mechanism of sorption in these carbon materials: physisorption controlled by Van der Waals attractive forces through London interaction is efficient at cryogenic temperatures (77 K) where the interaction between adsorbent and adsorbate becomes stronger. One way to improve the attractive interaction between adsorbent and molecule is to increase the forces due to the interaction of electrical field and induced dipole of the molecule. This can be theoretically tailored in carbon materials through the electron charge transfer by electron donors who can provide an increase in the electrical field al the surface of the adsorbent. Then, the doping of carbon substrates, appearing to be a promising method to increase the energy of adsorption has been proposed in recent papers as a solution to obtain good hydrogen adsorption properties at appropriate temperatures close to room temperatures [10-12]. Thus, we have studied the adsorption

  20. XPS study of palladium sensitized nano porous silicon thin film

    Indian Academy of Sciences (India)

    Keywords. Porous silicon; passivation; palladium; oxidation; XPS. Abstract. Nano porous silicon (PS) was formed on -type monocrystalline silicon of 2–5 cm resistivity and (100) orientation by electrochemical anodization method using HF and ethanol as the electrolytes. High density of surface states, arising due to its ...

  1. Hydrogen adsorption in doped porous carbons

    International Nuclear Information System (INIS)

    L Balan; L Duclaux; S Los

    2005-01-01

    properties of doped microporous carbons (SWNTs and activated carbons). The raw nano-structured carbon materials are microporous activated carbons (BET specific surface area: 1600 m 2 /g), electric-arc closed-end single-walled carbon nano-tubes (SWNTs), and HiPCO SWNTs. They have been doped in the vapour phase by K, and Li (in order to obtain KC 7 , KC 10 , LiC 18 SWNTs and LiC 6 , LiC 18 , KC 24 activated carbons). The hydrogen adsorption-desorption isotherms of the doped activated carbons were obtained at room temperature and at 77 K, up to 3 MPa, by a volumetric method. The adsorption of D 2 was studied in situ on doped nano-tubes and nano-filaments by neutron diffraction on D1B experiment (ILL), at λ=2.52 Angstroms, as a function of temperature [300 - 20 K] and pressure. Simultaneously the adsorption isotherms were recorded in the range 0 - 0.1 MPa [13]. Doping of microporous carbon by Li or K leads to an increase in the energy of adsorption of H 2 or D 2 Molecules. Thus, the room temperature sorption capacities (al P≤3 MPa) can be higher than that of the raw materials after slight doping. However, the maximum H 2 (or D 2 ) storage measured at T ≤ 77 K is lower than the one of pristine Materials as the sites of adsorption are occupied by alkali ions inserted in the micropores [14]. The microporous adsorption sites of doped single-walled carbon nano-tubes, identified by neutron diffraction, are both the interstitial voids (in electric-arc or HiPCO tubes) in between the tubes and the central canals of the tubes (only in HiPCO tubes) [15]. We have also prepared nano-structured porous doped carbons by ball-milling carbon host materials with some dopant, such as alkali or alkaline earth metal. The new nano-porous carbons obtained by this method have been characterised and tested for their hydrogen-adsorption properties. References: [1]A. Chambers et al, J. Phys. Chem. B, 102, 4253,1998. [2]A. C. Dillon et al, Nature, 386, 377,1997. [3]J. Conard, Ann. Chim. Sci. Mat 26

  2. Carbon nano tubes embedded in polymer nano fibers

    International Nuclear Information System (INIS)

    Dror, Y.; Kedem, S.; Khalfin, R.L.; Paz, Y.; Cohenl, Y.; Salalha, Y.; Yarin, A.L.; Zussman, A.

    2004-01-01

    Full Text: The electro spinning process was used successfully to embed Multi-walled carbon nano tubes (MWCNTs) and single-walled carbon nano tubes (SWCNTs) in a matrix of poly(ethylene oxide) (PEO) forming composite nano fibers. Initial dispersion of SWCNTs in water was achieved by the use of an amphphilic alternating copolymer of styrene and sodium maleate. MWNT dispersion was achieved by ionic and nonionic surfactants. The distribution and conformation of the nano tubes in the nano fibers were studied by transmission electron microscopy (TEM). Oxygen plasma etching was used to expose the nano tubes within the nano fibers to facilitate direct observation. Nano tube alignment within the nano fibers was shown to depend strongly on the quality of the initial dispersions. Well-dispersed and separated nano tubes were embedded in a straight and aligned form while entangled non-separated nano tubes were incorporated as dense aggregates. X-ray diffraction demonstrated a high degree of orientation of the PEO crystals in the electro spun nano fibers with embedded SWCNTs, whereas incorporation of MVCNTs had a detrimental effect on the polymer orientation. Composite polymer nano fibers containing dispersed phases of nanometric TiO 2 particles and MWCNTs were also prepared electro spinning. In this case, the polymer matrix was poly(acrylonitrile) (PAN). The morphology and possible applications of these composite nano fibers will be discussed

  3. TRANSFORMATIONS IN NANO-DIAMONDS WITH FORMATION OF NANO-POROUS SILICON CARBIDE AT HIGH PRESSURE

    Directory of Open Access Journals (Sweden)

    V. N. Kovalevsky

    2010-01-01

    Full Text Available The paper contains investigations on regularities of diamond - silicon carbide composite structure formation at impact-wave excitation. It has been determined that while squeezing a porous blank containing Si (SiC nano-diamond by explosive detonation products some processes are taking place such as diamond nano-particles consolidation, reverse diamond transition into graphite, fragments formation from silicon carbide. A method for obtaining high-porous composites with the presence of ultra-disperse diamond particles has been developed. Material with three-dimensional high-porous silicon-carbide structure has been received due to nano-diamond graphitation at impact wave transmission and plastic deformation. The paper reveals nano-diamonds inverse transformation into graphite and its subsequent interaction with the silicon accompanied by formation of silicon-carbide fragments with dimensions of up to 100 nm.

  4. Carbon nanotubes: from nano test tube to nano-reactor.

    Science.gov (United States)

    Khlobystov, Andrei N

    2011-12-27

    Confinement of molecules and atoms inside carbon nanotubes provides a powerful strategy for studying structures and chemical properties of individual molecules at the nanoscale. In this issue of ACS Nano, Allen et al. explore the nanotube as a template leading to the formation of unusual supramolecular and covalent structures. The potential of carbon nanotubes as reactors for synthesis on the nano- and macroscales is discussed in light of recent studies.

  5. Hydrogen Storage in Carbon Nano-materials

    International Nuclear Information System (INIS)

    David Eyler; Michel Junker; Emanuelle Breysse Carraboeuf; Laurent Allidieres; David Guichardot; Fabien Roy; Isabelle Verdier; Edward Mc Rae; Moulay Rachid Babaa; Gilles Flamant; David Luxembourg; Daniel Laplaze; Patrick Achard; Sandrine Berthon-Fabry; David Langohr; Laurent Fulcheri

    2006-01-01

    This paper presents the results of a French project related to hydrogen storage in carbon nano-materials. This 3 years project, co-funded by the ADEME (French Agency for the Environment and the Energy Management), aimed to assess the hydrogen storage capacity of carbon nano-materials. Four different carbon materials were synthesized and characterized in the frame of present project: - Carbon Nano-tubes; - Carbon Nano-fibres; - Carbon Aerogel; - Carbon Black. All materials tested in the frame of this project present a hydrogen uptake of less than 1 wt% (-20 C to 20 C). A state of the art of hydrogen storage systems has been done in order to determine the research trends and the maturity of the different technologies. The choice and design of hydrogen storage systems regarding fuel cell specifications has also been studied. (authors)

  6. Fabricating solid carbon porous electrodes from powders

    Science.gov (United States)

    Kaschmitter, James L.; Tran, Tri D.; Feikert, John H.; Mayer, Steven T.

    1997-01-01

    Fabrication of conductive solid porous carbon electrodes for use in batteries, double layer capacitors, fuel cells, capacitive dionization, and waste treatment. Electrodes fabricated from low surface area (Electrodes having a higher surface area, fabricated from powdered carbon blacks, such as carbon aerogel powder, carbon aerogel microspheres, activated carbons, etc. yield high conductivity carbon compositives with excellent double layer capacity, and can be used in double layer capacitors, or for capacitive deionization and/or waste treatment of liquid streams. By adding metallic catalysts to be high surface area carbons, fuel cell electrodes can be produced.

  7. 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)

  8. The effect of magnetohydrodynamic nano fluid flow through porous cylinder

    Science.gov (United States)

    Widodo, Basuki; Arif, Didik Khusnul; Aryany, Deviana; Asiyah, Nur; Widjajati, Farida Agustini; Kamiran

    2017-08-01

    This paper concerns about the analysis of the effect of magnetohydrodynamic nano fluid flow through horizontal porous cylinder on steady and incompressible condition. Fluid flow is assumed opposite gravity and induced by magnet field. Porous cylinder is assumed had the same depth of porous and was not absorptive. The First thing to do in this research is to build the model of fluid flow to obtain dimentional governing equations. The dimentional governing equations are consist of continuity equation, momentum equation, and energy equation. Furthermore, the dimensional governing equations are converted to non-dimensional governing equation by using non-dimensional parameters and variables. Then, the non-dimensional governing equations are transformed into similarity equations using stream function and solved using Keller-Box method. The result of numerical solution further is obtained by taking variation of magnetic parameter, Prandtl number, porosity parameter, and volume fraction. The numerical results show that velocity profiles increase and temperature profiles decrease when both of the magnetic and the porosity parameter increase. However, the velocity profiles decrease and the temperature profiles increase when both of the magnetic and the porosity parameter increase.

  9. Transparent, flexible supercapacitors from nano-engineered carbon films

    Science.gov (United States)

    Jung, Hyun Young; Karimi, Majid B.; Hahm, Myung Gwan; Ajayan, Pulickel M.; Jung, Yung Joon

    2012-10-01

    Here we construct mechanically flexible and optically transparent thin film solid state supercapacitors by assembling nano-engineered carbon electrodes, prepared in porous templates, with morphology of interconnected arrays of complex shapes and porosity. The highly textured graphitic films act as electrode and current collector and integrated with solid polymer electrolyte, function as thin film supercapacitors. The nanostructured electrode morphology and the conformal electrolyte packaging provide enough energy and power density for the devices in addition to excellent mechanical flexibility and optical transparency, making it a unique design in various power delivery applications.

  10. Nano-CT study on nanostructure of porous ceramics

    International Nuclear Information System (INIS)

    Wu Wenquan; Li Wenjie; Guan Yong; Yang Yunhao; Chen Jie; Zhou Jie; Yu Xiyue; Song Xiangxia; Tian Yangchao; Li Wei; Chen Chusheng

    2010-01-01

    The porous structure of ceramic materials has a great impact on their performance. However, the existing characterization techniques fail to give 3D structure of the ceramics. In this work, nano-CT imaging technique was used to study 3D structure of a ceramic fiber tube prepared by a phase inversion technology. The results showed the shape, direction, size distribution, and 3D map of the pores inside the ceramic wall. The pore size is 0.4-1.5 μm, with a porosity of 38.31%. The data can be used to improve their preparation processes and optimize the structure parameters, for applications in chemical, energy, environmental protection and other fields. (authors)

  11. Preparation and characterization of nanocomposite of graphitic carbon nitride and TiO2 as a porous support for nano catalyst for desulfurization process

    Directory of Open Access Journals (Sweden)

    Ezzat Rafiee

    2017-12-01

    Full Text Available A novel heterogeneous nanocatalyst H3PW12O40/TiO2/g-C3N4 (PW/TiO2/CN was successfully synthesized by immobilization of PW on TiO2/CN nanocomposite, and characterized by SEM, BET, FT-IR, XRD, EDX, TEM and ICP. Catalytic performance of the as-prepared catalyst was investigated for the selective oxidation of sulfides to sulfoxides and sulfones in the presence of H2O2 as oxidant with good conversion and high selectivity. The main factors influencing the ability for selective oxidation of sulfides were studied, including reaction temperature, amounts of the catalyst, H2O2 and type of the reaction solvent. Catalytic oxidation of the different model oils containing dibenzothiophene (DBT, benzothiophene (BT and thiophene (T into corresponding sulfone was also studied. Effects of different extractive solvents, aromatics, alkenes and nitrogen compounds on the oxidative desulfurization processes (ODS were also studied. In addition, reducing the level of sulfur content in real oil was investigated. The recyclability of the PW/TiO2/CN nanocatalyst for various cycles without a significant loss of activity was proved. The heterogeneity of the as-prepared catalyst was confirmed by leaching tests. Keywords: Graphitic carbon nitride, Extraction, Tetrabutyl titanate, Heteropoly acid, Oxidative desulfurization, Oil

  12. Dynamics of Nano-Chain Diffusing in Porous Media

    International Nuclear Information System (INIS)

    Chen Jiang-Xing; Zheng Qiang; Huang Chun-Yun; Xu Jiang-Rong; Ying He-Ping

    2015-01-01

    A coarse-grained model is proposed to study the dynamics of a nano-chain diffusing in porous media. The simulation utilizes a hybrid method which combines stochastic rotation dynamics with molecular dynamics. Solvent molecules are explicitly taken into account to represent the hydrodynamic interactions and random fluctuations. The conformation, relaxation, and diffusion properties of a polymer chain are investigated by changing the density degree of the obstacle matrix. It is found that the average size of the chain is a nonmonotonic function of the obstacle volume fraction ϕ. A dense environment may contribute to extending a linear chain, which can be characterized by larger exponents in the corresponding power law. The relaxation behavior of a stretched chain to a steady state shows dramatic crossover from exponent to power-law relaxation when the values of φ are increased. The dependence of the diffusion coefficient on the chain size is also studied. Various kinds of scaling properties are presented and discussed. The results can give additional insight into the density effect of porous media on polymer structure and dynamics. (paper)

  13. Mechanical performance of porous concrete pavement containing nano black rice husk ash

    Science.gov (United States)

    Ibrahim, M. Y. Mohd; Ramadhansyah, P. J.; Rosli, H. Mohd; Ibrahim, M. H. Wan

    2018-01-01

    This paper presents an experimental research on the performance of nano black rice husk ash on the porous concrete pavement properties. The performance of the porous concrete pavement mixtures was investigated based on their compressive strength, flexural strength, and splitting tensile strength. The results indicated that using nano material from black rice husk ash improved the mechanical properties of porous concrete pavement. In addition, the result of compressive, flexural, and splitting tensile strength was increased with increasing in curing age. Finally, porous concrete pavement with 10% replacement levels exhibited an excellent performance with good strength compared to others.

  14. Fabrication of novel micro-nano carbonous composites based on self-made hollow activated carbon fibers

    Energy Technology Data Exchange (ETDEWEB)

    Kong Yuxia; Qiu Tingting [School of Materials Science and Engineering, Tongji University, Shanghai 201804 (China); Qiu Jun, E-mail: qiujun@tongji.edu.cn [School of Materials Science and Engineering, Tongji University, Shanghai 201804 (China); Key Laboratory of Advanced Civil Engineering Materials of Education of Ministry, Shanghai 201804 (China)

    2013-01-15

    Highlights: Black-Right-Pointing-Pointer Hollow pipe and porous HACF with solid carbon net framework structure were successfully prepared by template method. Black-Right-Pointing-Pointer CNTs were grown successfully on the self-made HACF substrate by CVD techniques. Black-Right-Pointing-Pointer A novel tree-like micro-nano carbonous structure CNTs/HACF was fabricated. Black-Right-Pointing-Pointer The formation mechanism of micro phase HACF and nano phase CNTs were respectively discussed. - Abstract: The hollow activated carbon fibers (HACF) were prepared by using commercial polypropylene hollow fiber (PPHF) as the template, and phenol-formaldehyde resin (PF) as carbon precursors. Final HACF was formed through the thermal decomposition and carbonization of PF at 700 Degree-Sign C under the nitrogen atmosphere, and activation at 800 Degree-Sign C with carbon dioxide as the activating agent, consecutively. Then, carbon nanotubes (CNTs) were grown by chemical vapor deposition (CVD) techniques using the as-grown porous HACF as substrate. The growth process was achieved by pyrolyzing ethanol steam at 700 Degree-Sign C using nickel as catalyst. Finally, CNTs was grown successfully on the substrate, and a novel tree-like micro-nano carbonous structure CNTs/HACF was fabricated. The as-grown HACF and micro-nano CNTs/HACF were characterized by scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD), and thermogravimetric analysis (TG), respectively. Moreover, the formation mechanisms were also discussed.

  15. Effect of Nano Silica on the Physical Property of Porous Concrete Pavement

    Science.gov (United States)

    Yusak, Mohd Ibrahim Mohd; Ezree Abdullah, Mohd; Putra Jaya, Ramadhansyah; Rosli Hainin, Mohd; Ibrahim, Mohd Haziman Wan

    2017-08-01

    Rice husk can be categorized as an organic waste material from paddy industries. Silica is a major inorganic element of the rice husk. The aim of present study is to evaluate the effect of Nano silica on the physical properties of porous concrete pavement. Rice husk has been burned in the furnace (650°C for 6 hours) and ground for four different grinding times (33, 48, 63 and 81 hours). Five types of mixes were prepared to evaluate the different Nano silica grinding time. A Nano silica dosage of 10% by weight of binder was used throughout the experiments. The physical properties were examined through compressive strength, transmission electron microscopy and x-ray fluorescence. The experimental results indicate that the different Nano size gives a different effect to porous concrete strength. Based on the results obtained, Nano silica ground for 63 hours (65.84nm) gives the best result and performance to porous concrete pavement specimens.

  16. Nano-yarn carbon nanotube fiber based enzymatic glucose biosensor

    International Nuclear Information System (INIS)

    Zhu Zhigang; Burugapalli, Krishna; Moussy, Francis; Song, Wenhui; Li Yali; Zhong Xiaohua

    2010-01-01

    A novel brush-like electrode based on carbon nanotube (CNT) nano-yarn fiber has been designed for electrochemical biosensor applications and its efficacy as an enzymatic glucose biosensor demonstrated. The CNT nano-yarn fiber was spun directly from a chemical-vapor-deposition (CVD) gas flow reaction using a mixture of ethanol and acetone as the carbon source and an iron nano-catalyst. The fiber, 28 μm in diameter, was made of bundles of double walled CNTs (DWNTs) concentrically compacted into multiple layers forming a nano-porous network structure. Cyclic voltammetry study revealed a superior electrocatalytic activity for CNT fiber compared to the traditional Pt-Ir coil electrode. The electrode end tip of the CNT fiber was freeze-fractured to obtain a unique brush-like nano-structure resembling a scale-down electrical 'flex', where glucose oxidase (GOx) enzyme was immobilized using glutaraldehyde crosslinking in the presence of bovine serum albumin (BSA). An outer epoxy-polyurethane (EPU) layer was used as semi-permeable membrane. The sensor function was tested against a standard reference electrode. The sensitivities, linear detection range and linearity for detecting glucose for the miniature CNT fiber electrode were better than that reported for a Pt-Ir coil electrode. Thermal annealing of the CNT fiber at 250 deg. C for 30 min prior to fabrication of the sensor resulted in a 7.5 fold increase in glucose sensitivity. The as-spun CNT fiber based glucose biosensor was shown to be stable for up to 70 days. In addition, gold coating of the electrode connecting end of the CNT fiber resulted in extending the glucose detection limit to 25 μM. To conclude, superior efficiency of CNT fiber for glucose biosensing was demonstrated compared to a traditional Pt-Ir sensor.

  17. Nano-yarn carbon nanotube fiber based enzymatic glucose biosensor

    Science.gov (United States)

    Zhu, Zhigang; Song, Wenhui; Burugapalli, Krishna; Moussy, Francis; Li, Ya-Li; Zhong, Xiao-Hua

    2010-04-01

    A novel brush-like electrode based on carbon nanotube (CNT) nano-yarn fiber has been designed for electrochemical biosensor applications and its efficacy as an enzymatic glucose biosensor demonstrated. The CNT nano-yarn fiber was spun directly from a chemical-vapor-deposition (CVD) gas flow reaction using a mixture of ethanol and acetone as the carbon source and an iron nano-catalyst. The fiber, 28 µm in diameter, was made of bundles of double walled CNTs (DWNTs) concentrically compacted into multiple layers forming a nano-porous network structure. Cyclic voltammetry study revealed a superior electrocatalytic activity for CNT fiber compared to the traditional Pt-Ir coil electrode. The electrode end tip of the CNT fiber was freeze-fractured to obtain a unique brush-like nano-structure resembling a scale-down electrical 'flex', where glucose oxidase (GOx) enzyme was immobilized using glutaraldehyde crosslinking in the presence of bovine serum albumin (BSA). An outer epoxy-polyurethane (EPU) layer was used as semi-permeable membrane. The sensor function was tested against a standard reference electrode. The sensitivities, linear detection range and linearity for detecting glucose for the miniature CNT fiber electrode were better than that reported for a Pt-Ir coil electrode. Thermal annealing of the CNT fiber at 250 °C for 30 min prior to fabrication of the sensor resulted in a 7.5 fold increase in glucose sensitivity. The as-spun CNT fiber based glucose biosensor was shown to be stable for up to 70 days. In addition, gold coating of the electrode connecting end of the CNT fiber resulted in extending the glucose detection limit to 25 µM. To conclude, superior efficiency of CNT fiber for glucose biosensing was demonstrated compared to a traditional Pt-Ir sensor.

  18. Porous carbons prepared by direct carbonization of MOFs for supercapacitors

    Science.gov (United States)

    Yan, Xinlong; Li, Xuejin; Yan, Zifeng; Komarneni, Sridhar

    2014-07-01

    Three porous carbons were prepared by direct carbonization of HKUST-1, MOF-5 and Al-PCP without additional carbon precursors. The carbon samples obtained by carbonization at 1073 K were characterized by XRD, TEM and N2 physisorption techniques followed by testing for electrochemical performance. The BET surface areas of the three carbons were in the range of 50-1103 m2/g. As electrode materials for supercapacitor, the MOF-5 and Al-PCP derived carbons displayed the ideal capacitor behavior, whereas the HKUST-1 derived carbon showed poor capacitive behavior at various sweep rates and current densities. Among those carbon samples, Al-PCP derived carbons exhibited highest specific capacitance (232.8 F/g) in 30% KOH solution at the current density of 100 mA/g.

  19. DNA damage due to perfluorooctane sulfonate based on nano-gold embedded in nano-porous poly-pyrrole film

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Liping, E-mail: lipinglu@bjut.edu.cn; Xu, Laihui; Kang, Tianfang; Cheng, Shuiyuan

    2013-11-01

    DNA damage induced from perfluorooctane sulfonate (PFOS) was further developed on a nano-porous bionic interface. The interface was formed by assembling DNA on nano-gold particles which were embedded in a nano-porous overoxidized polypyrrole film (OPPy). Atomic force microscopy, scanning electron microscope and electrochemical investigations indicate that OPPy can be treated to form nano-pore structures. DNA damage due to PFOS was proved using electrochemistry and X-ray photoelectron spectroscopy (XPS) and was investigated by detecting differential pulse voltammetry (DPV) response of methylene blue (MB) which was used as electro-active indicator in the system. The current of MB attenuates obviously after incubation of DNA in PFOS. Moreover, electrochemical impedance spectroscopy (EIS) demonstrates that PFOS weakens DNA charge transport. The tentative binding ratio of PFOS: DNA base pair was obtained by analyzing XPS data of this system.

  20. Synthesis and structural characterization of coaxial nano tubes intercalated of molybdenum disulfide with carbon

    International Nuclear Information System (INIS)

    Reza San German, C.M.

    2005-01-01

    In this work the study of some fundamental aspects in the growth of unidimensional systems of coaxial nano tubes from the mold method is approached. This method is an inclusion technique of a precursor reagent into oxide nano porous alumina film (mold), and later applying some processes of synthesis it is gotten to obtain the wished material. The synthesized structures are identified later because they take place by means of the initial formation of nano tubes of MoS 2 , enclosing to carbon nano tubes by the same method, with propylene flow which generates a graphitization process that 'copy' the mold through as it flows. Binary phase MoS 2 + C nano tubes were synthesized by propylene pyrolysis inside MoS 2 nano tubes prepared by template assisted technique. The large coaxial nano tubes constituted of graphite sheets inserted between the MoS 2 layers forming the outer part, and coaxial multi wall carbon nano tubes (MWCNT) intercalated with MoS 2 inside. High resolution electron microscopy (HRTEM), electron energy loss spectroscopy (EELS), high angle annular dark field (HAADF), gatan image filter (GIF), nano beam electron diffraction patterns (NBEDP), along with molecular dynamics simulation and quantum mechanical calculations were used to characterize the samples. The one-dimensional structures exhibit diverse morphologies such as long straight and twisted nano tubes with several structural irregularities. The inter-planar spacing between MoS 2 layers was found to increase from 6.3 to 7.4 A due to intercalation with carbon. Simulated HREM images revealed the presence of these twisted nano structures, with mechanical stretch into intercalate carbon between MoS 2 layers. Our results open up the possibility of using MoS 2 nano tubes as templates for the synthesis of new one- dimensional binary phase systems. (Author)

  1. Deformation behavior of nano-porous polycrystalline silver. Part II: Simulations

    International Nuclear Information System (INIS)

    Zabihzadeh, S.; Cugnoni, J.; Duarte, L.I.; Van Petegem, S.; Van Swygenhoven, H.

    2017-01-01

    Three-dimensional finite element simulations of nano-porous silver structures are performed to understand the correlation between the porous morphology and the mechanical behavior. The nanostructures have been obtained from ptychographic X-ray computed tomography. The simulations allow distinguishing between the interplay and role of the ligament size, the pore morphology and the porosity, and therefore provide a better comprehension of the experimental observations. We show that the proposed model has a predictive character for mechanical behavior of nano-porous silver.

  2. Preparation of porous nano barium ferrite and its adsorption properties on uranium

    International Nuclear Information System (INIS)

    Xiong Guoxuan; Huang Haiqing; Zhang Zhibin

    2012-01-01

    The porous nano barium ferrite was made of Fe(NO 3 ) 3 and Ba(NO 3 ) 2 as raw materials, CTAB as surfactant by method of sol-gel and self-propagating combustion. The composition, morphology and magnetic properties of nano-rod barium ferrite were characterized by XRD, SEM and vibrating sample magnetometer. The adsorption properties of porous nano barium ferrite on uranium were studied with static adsorption and the effects of pH, adsorption temperature and oscillation time on adsorption properties were discussed. The results indicate that the average particle size of porous nano barium ferrite is 45-65 nm, the saturation magnetization and coercivity are 62.83 emu/g and 5481.0 Oe, respectively. Under the condition of the porous nano barium ferrite amount of 0.02 g, pH of 6, adsorption temperature of 25℃ and oscillation time of 30 min, the adsorption capacity of uranium on the porous nano barium ferrite reaches 921 μg/g. (authors)

  3. Synthesis of porous silicon nano-wires and the emission of red luminescence

    International Nuclear Information System (INIS)

    Congli, Sun; Hao, Hu; Huanhuan, Feng; Jingjing, Xu; Yu, Chen; Yong, Jin; Zhifeng, Jiao; Xiaosong, Sun

    2013-01-01

    This very paper is focusing on the characterization of porous silicon nano-wires prepared via a two-step route, the electroless chemical etching and the following post-treatment of HF/HNO 3 solution. Hence, scanning electron microscopy, transmission electron microscopy and confocal fluorescence microscopy are employed for this purpose. From the results of experiments, one can find that the as-prepared silicon nano-wire is of smooth surface and that no visible photo-luminescence emission could be seen. However, the porous structure can be found in the silicon nano-wire treated with HF/HNO 3 solution, and the clear photo-luminescence emission of 630 nm can be recorded with a confocal fluorescence microscope. The transmission electron microscopy test tells that the porous silicon nano-wire is made up of a porous crystalline silicon nano-core and a rough coating of silicon oxide. Besides, based on the post-HF- and -H 2 O 2 - treatments, the emission mechanism of the red luminescence has been discussed and could be attributed to the quantum confinement/luminescence center model which could be simply concluded as that the electron–hole pairs are mainly excited inside the porous silicon nano-core and then tunneling out and recombining at the silicon oxide coating.

  4. Synthesis of porous silicon nano-wires and the emission of red luminescence

    Energy Technology Data Exchange (ETDEWEB)

    Congli, Sun [School of Materials Science and Engineering, Sichuan University (China); Hao, Hu [National Engineering Research Center for Biomaterials, Sichuan University, Chengdu 610064, Sichuan (China); Huanhuan, Feng; Jingjing, Xu; Yu, Chen; Yong, Jin; Zhifeng, Jiao [School of Materials Science and Engineering, Sichuan University (China); Xiaosong, Sun, E-mail: sunxs@scu.edu.cn [School of Materials Science and Engineering, Sichuan University (China)

    2013-10-01

    This very paper is focusing on the characterization of porous silicon nano-wires prepared via a two-step route, the electroless chemical etching and the following post-treatment of HF/HNO{sub 3} solution. Hence, scanning electron microscopy, transmission electron microscopy and confocal fluorescence microscopy are employed for this purpose. From the results of experiments, one can find that the as-prepared silicon nano-wire is of smooth surface and that no visible photo-luminescence emission could be seen. However, the porous structure can be found in the silicon nano-wire treated with HF/HNO{sub 3} solution, and the clear photo-luminescence emission of 630 nm can be recorded with a confocal fluorescence microscope. The transmission electron microscopy test tells that the porous silicon nano-wire is made up of a porous crystalline silicon nano-core and a rough coating of silicon oxide. Besides, based on the post-HF- and -H{sub 2}O{sub 2}- treatments, the emission mechanism of the red luminescence has been discussed and could be attributed to the quantum confinement/luminescence center model which could be simply concluded as that the electron–hole pairs are mainly excited inside the porous silicon nano-core and then tunneling out and recombining at the silicon oxide coating.

  5. Characterization of Lignocellulosic Biomass as Raw Material for the Production of Porous Carbon-based Materials

    Directory of Open Access Journals (Sweden)

    Saptadi Darmawan

    2016-02-01

    Full Text Available Lignocellulosic biomass is a potential raw material that can be used in the synthesis (manufacture of porous carbon stuffs. The properties of such porous carbon products are affected by the species of the raw material and the manufacturing process, among other things. This paper scrutinizes the related characteristics of lignocellulosic raw materials that indicate potential for the production of porous carbon. Three species were used: pine (Pinus merkusii wood, mangium (Acacia mangium wood, and candlenut (Aleurites moluccana shells, representing softwoods, hardwoods, and non-wood stuffs, respectively. Analyses of their chemical compounds and proximate contents were carried out. Additionally, nano scale scrutiny of the lignocellulosic biomass was also conducted using the nano capable instruments, which consisted of SEM, EDS, XRD, FTIR, and DSC. Results revealed that pine wood had the most potential to produce porous carbon. Morphologically, pine wood afforded the best permeability, whereby at the structure of monoclinic cellulose crystals, there were cellulose-I(alpha structures, which contained less cellulose-I(beta structures. Furthermore, pine wood exhibited greater volatile matter content, as confirmed through the FTIR, which greatly assisted the forming of porosity inside its corresponding carbon.

  6. Characteristics Of The Porous Body Sintered By Nano-Sized Fe-Cr-Al Alloy Powder

    Directory of Open Access Journals (Sweden)

    Lee Su-In

    2015-06-01

    Full Text Available Porous metal with uniform honeycomb structure was successfully produced by sintering using Fe-Cr-Al nano powder, which was prepared by the pulsed wire evaporation (PWE in ethanol. Its process consisted of the several steps; 1 coating on the surface of polyurethane sponge with the liquid droplets generated from the ethanol-based slurry where the Fe-Cr-Al nano powders were uniformly dispersed, 2 heat treatment of debinding to remove the polyurethane sponge and 3 sintering of the porous green body formed by Fe-Cr-Al nano powders. The strut thickness of porous Fe-Cr-Al was increased by the increase of spraying times in ESP step. Also, The shrinkages and the oxidation resistance of the sintered porous body was increased with increase of sintering temperature. The optimal sintering temperature was shown to 1450°C in views to maximize the oxidation resistance and sinterability.

  7. Carbon Nanotube Templated Microfabrication of Porous Silicon-Carbon Materials

    Science.gov (United States)

    Song, Jun; Jensen, David; Dadson, Andrew; Vail, Michael; Linford, Matthew; Vanfleet, Richard; Davis, Robert

    2010-10-01

    Carbon nanotube templated microfabrication (CNT-M) of porous materials is demonstrated. Partial chemical infiltration of three dimensional carbon nanotube structures with silicon resulted in a mechanically robust material, precisely structured from the 10 nm scale to the 100 micron scale. Nanoscale dimensions are determined by the diameter and spacing of the resulting silicon/carbon nanotubes while the microscale dimensions are controlled by lithographic patterning of the CNT growth catalyst. We demonstrate the utility of this hierarchical structuring approach by using CNT-M to fabricate thin layer chromatography (TLC) separations media with precise microscale channels for fluid flow control and nanoscale porosity for high analyte capacity.

  8. Porous Si spheres encapsulated in carbon shells with enhanced anodic performance in lithium-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Hui; Wu, Ping, E-mail: zjuwuping@njnu.edu.cn; Shi, Huimin; Lou, Feijian; Tang, Yawen; Zhou, Tongge; Zhou, Yiming, E-mail: zhouyiming@njnu.edu.cn; Lu, Tianhong

    2014-07-01

    Highlights: • In situ magnesiothermic reduction route for the formation of porous Si@C spheres. • Unique microstructural characteristics of both porous sphere and carbon matrix. • Enhanced anodic performance in term of cycling stability for lithium-ion batteries. - Abstract: A novel type of porous Si–C micro/nano-hybrids, i.e., porous Si spheres encapsulated in carbon shells (porous Si@C spheres), has been constructed through the pyrolysis of polyvinylidene fluoride (PVDF) and subsequent magnesiothermic reduction methodology by using SiO{sub 2} spheres as precursors. The as-synthesized porous Si@C spheres have been applied as anode materials for lithium-ion batteries (LIBs), and exhibit enhanced anodic performance in term of cycling stability compared with bare Si spheres. For example, the porous Si@C spheres are able to exhibit a high reversible capacity of 900.0 mA h g{sup −1} after 20 cycles at a current density of 0.05 C (1 C = 4200 mA g{sup −1}), which is much higher than that of bare Si spheres (430.7 mA h g{sup −1})

  9. Porous Si spheres encapsulated in carbon shells with enhanced anodic performance in lithium-ion batteries

    International Nuclear Information System (INIS)

    Wang, Hui; Wu, Ping; Shi, Huimin; Lou, Feijian; Tang, Yawen; Zhou, Tongge; Zhou, Yiming; Lu, Tianhong

    2014-01-01

    Highlights: • In situ magnesiothermic reduction route for the formation of porous Si@C spheres. • Unique microstructural characteristics of both porous sphere and carbon matrix. • Enhanced anodic performance in term of cycling stability for lithium-ion batteries. - Abstract: A novel type of porous Si–C micro/nano-hybrids, i.e., porous Si spheres encapsulated in carbon shells (porous Si@C spheres), has been constructed through the pyrolysis of polyvinylidene fluoride (PVDF) and subsequent magnesiothermic reduction methodology by using SiO 2 spheres as precursors. The as-synthesized porous Si@C spheres have been applied as anode materials for lithium-ion batteries (LIBs), and exhibit enhanced anodic performance in term of cycling stability compared with bare Si spheres. For example, the porous Si@C spheres are able to exhibit a high reversible capacity of 900.0 mA h g −1 after 20 cycles at a current density of 0.05 C (1 C = 4200 mA g −1 ), which is much higher than that of bare Si spheres (430.7 mA h g −1 )

  10. Flexural Properties of Activated Carbon Filled Epoxy Nano composites

    International Nuclear Information System (INIS)

    Khalil, H.P.S.A.; Khalil, H.P.S.A.; Alothman, O.Y.; Paridah, M.T.; Zainudin, E.S.

    2014-01-01

    Activated carbon (AC) filled epoxy nano composites obtained by mixing the desired amount of nano AC viz., bamboo stem, oil palm empty fruit bunch, and coconut shell from agricultural biomass with the epoxy resin. Flexural properties of activated carbons filled epoxy nano composites with 1 %, and 5 % filler loading were measured. In terms of flexural strength and modulus, a significant increment was observed with addition of 1 % vol and 5 % vol nano-activated carbon as compared to neat epoxy. The effect of activated carbon treated by two chemical agents (potassium hydroxide and phosphoric acid) on the flexural properties of epoxy nano composites were also investigated. Flexural strength of activated carbon-bamboo stem, activated carbon-oil palm, and activated carbon-coconut shell reinforced epoxy nano composites showed almost same value in case of 5 % potassium hydroxide activated carbon. Flexural strength of potassium hydroxide activated carbon-based epoxy nano composites was higher than phosphoric acid activated carbon. The flexural toughness of both the potassium hydroxide and phosphoric acid activated carbon reinforced composites range between 0.79 - 0.92 J. It attributed that developed activated carbon filled epoxy nano composites can be used in different applications. (author)

  11. Growth control of carbon nanotubes using by anodic aluminum oxide nano templates.

    Science.gov (United States)

    Park, Yong Seob; Choi, Won Seek; Yi, Junsin; Lee, Jaehyeong

    2014-05-01

    Anodic Aluminum Oxide (AAO) template prepared in acid electrolyte possess regular and highly anisotropic porous structure with pore diameter range from five to several hundred nanometers, and with a density of pores ranging from 10(9) to 10(11) cm(-2). AAO can be used as microfilters and templates for the growth of CNTs and metal or semiconductor nanowires. Varying anodizing conditions such as temperature, electrolyte, applied voltage, anodizing and widening time, one can control the diameter, the length, and the density of pores. In this work, we deposited Al thin film by radio frequency magnetron sputtering method to fabricate AAO nano template and synthesized multi-well carbon nanotubes on a glass substrate by microwave plasma-enhanced chemical vapor deposition (MPECVD). AAO nano-porous templates with various pore sizes and depths were introduced to control the dimension and density of CNT arrays. The AAO nano template was synthesize on glass by two-step anodization technique. The average diameter and interpore distance of AAO nano template are about 65 nm and 82 nm. The pore density and AAO nano template thickness are about 2.1 x 10(10) pores/cm2 and 1 microm, respectively. Aligned CNTs on the AAO nano template were synthesized by MPECVD at 650 degrees C with the Ni catalyst layer. The length and diameter of CNTs were grown 2 microm and 50 nm, respectively.

  12. Applications and Nano toxicity of Carbon Nano tubes and Graphene in Biomedicine Caitlin Fisher

    International Nuclear Information System (INIS)

    Rider, A.E.; Han, Z.J.; Kumar, S.; Levchenko, L.; Ostrikov, K.K.

    2012-01-01

    Owing to their unique mechanical, electrical, optical, and thermal properties, carbon nano structures including carbon nano tubes and graphenes show great promise for advancing the fields of biology and medicine. Many reports have demonstrated the promise of these carbon nano structures and their hybrid structures (composites with polymers, ceramics, and metal nanoparticles, etc.) for a variety of biomedical areas ranging from bio sensing, drug delivery, and diagnostics, to cancer treatment, tissue engineering, and bio terrorism prevention. However, the issue of the safety and toxicity of these carbon nano structures, which is vital to their use as diagnostic and therapeutic tools in biomedical fields, has not been completely resolved. This paper aims to provide a summary of the features of carbon nano tube and graphene-based materials and current research progress in biomedical applications. We also highlight the current opinions within the scientific community on the toxicity and safety of these carbon structures

  13. Micro-and/or nano-scale patterned porous membranes, methods of making membranes, and methods of using membranes

    KAUST Repository

    Wang, Xianbin; Chen, Wei; Wang, Zhihong; Zhang, Xixiang; Yue, Weisheng; Lai, Zhiping

    2015-01-01

    Embodiments of the present disclosure provide for materials that include a pre-designed patterned, porous membrane (e.g., micro- and/or nano-scale patterned), structures or devices that include a pre-designed patterned, porous membrane, methods of making pre-designed patterned, porous membranes, methods of separation, and the like.

  14. Micro-and/or nano-scale patterned porous membranes, methods of making membranes, and methods of using membranes

    KAUST Repository

    Wang, Xianbin

    2015-01-22

    Embodiments of the present disclosure provide for materials that include a pre-designed patterned, porous membrane (e.g., micro- and/or nano-scale patterned), structures or devices that include a pre-designed patterned, porous membrane, methods of making pre-designed patterned, porous membranes, methods of separation, and the like.

  15. Characterization of a porous nano-electrospray capillary emitter at ultra-low flow rates

    Czech Academy of Sciences Publication Activity Database

    Járvás, G.; Fonslow, B.; Yates III, J. R.; Foret, František; Guttman, A.

    2017-01-01

    Roč. 55, č. 1 (2017), s. 47-51 ISSN 0021-9665 R&D Projects: GA ČR(CZ) GBP206/12/G014 Institutional support: RVO:68081715 Keywords : nano-electrospray * ion suppression * porous joint Subject RIV: CB - Analytical Chemistry, Separation OBOR OECD: Analytical chemistry Impact factor: 0.984, year: 2016

  16. Synthesis of nano-carbon (nanotubes, nanofibres, graphene ...

    Indian Academy of Sciences (India)

    Administrator

    – .... PEO composites. In other carbon nano materials such as graphite nano- fibres (GNFs) .... decides the catalyst shape according to which the mor- phology of the .... Castro M, Lu J, Bruzaud S, Kumar B and Feller J 2009 Carbon. 47 1930.

  17. The effect of brushing with nano calcium carbonate and calcium carbonate toothpaste on the surface roughness of nano-ionomer

    Science.gov (United States)

    Anisja, D. H.; Indrani, D. J.; Herda, E.

    2017-08-01

    Nanotechnology developments in dentistry have resulted in the development of nano-ionomer, a new restorative material. The surface roughness of restorative materials can increase bacteria adhesion and lead to poor oral hygiene. Abrasive agents in toothpaste can alter tooth and restorative material surfaces. The aim of this study is to identify the effect of brushing with nano calcium carbonate, and calcium carbonate toothpaste on surface roughness of nano-ionomer. Eighteen nano-ionomer specimens were brushed with Aquabidest (doubledistilled water), nano calcium carbonate and calcium carbonate toothpaste. Brushing lasted 30 minutes, and the roughness value (Ra) was measured after each 10 minute segment using a surface roughness tester. The data was analyzed using repeated ANOVA and one-way ANOVA test. The value of nano-ionomer surface roughness increased significantly (p<0.05) after 20 minutes of brushing with the nano calcium carbonate toothpaste. Brushing with calcium carbonate toothpaste leaves nano-ionomer surfaces more rugged than brushing with nano calcium carbonate toothpaste.

  18. Nano surface generation of grinding process using carbon nano tubes

    Indian Academy of Sciences (India)

    Nano surface finish has become an important parameter in the semiconductor, optical, electrical and mechanical industries. The materials used in these industries are classified as difficult to machine materials such as ceramics, glasses and silicon wafers. Machining of these materials up to nano accuracy is a great ...

  19. Preparation and cellular response of porous A-type carbonated hydroxyapatite nanoceramics

    International Nuclear Information System (INIS)

    Li Bo; Liao Xiaoling; Zheng Li; He Huawei; Wang Hong; Fan Hongsong; Zhang Xingdong

    2012-01-01

    Microwave sintering using the activated carbon as embedding material was applied in preparation of porous A-type carbonated hydroxyapatite ceramics with nano(nCHA) and submicron (mCHA) structure. By examining the linear shrinkages and the compressive strengths of samples at different temperatures, a suitable microwave sintering temperature was achieved. The microwave sintering method was successfully used to prepare A-type CHA with nano or submicron structure, and the mechanism of the formation of A-type carbonate groups was discussed also. Compared with the samples prepared by the conventional sintering method (mHA), the nCHA bioceramics synthesized by the microwave sintering approach had smaller grain size and more uniform microstructure, and showed a compressive strength similar to the conventional samples. In vitro dissolution test proved that nCHA exhibits better degradation property in comparison to pure HA. Rat osteoblasts were cultured with nCHA, mCHA and mHA to evaluate their biocompatibility, and nCHA showed significant enhancement of cells in attachment, proliferation and differentiation. In conclusion, carbonate groups can be easily introduced to HA crystal structure using the activated carbon as embedding material, and microwave sintering is an effective and simple method in preparing A-type CHA with a nanostructure. Results from this in vitro biological study suggest that porous A-type carbonated hydroxyapatite nanoceramics may be a much better candidate for clinical use in terms of bioactivity. - Highlights: ► We prepared porous A-type carbonated hydroxyapatite nanoceramics with microwave sintering. ► We examined physico-chemical characterization and osteoblast response. ► The nanoceramics have a comparable compressive strength to samples with conventional sintering method. ► The nanoceramics enhance degradation property, osteoblast proliferation and differentiation. ► The activated carbon is favorable for preheating samples and providing

  20. Some Observations on Carbon Nano tubes Susceptibility to Cell Phagocytosis

    International Nuclear Information System (INIS)

    Fraczek-Szczypta, A.; Menaszek, E.; Blazewicz, S.; Menaszek, E.

    2011-01-01

    The aim of this study was to assess the influence of different types of carbon nano tubes (CNTs) on cell phagocytosis. Three kinds of carbon nano tubes: single-walled carbon nano horns (SWCNHs), multi walled carbon nano tubes (MWCNTs), and ultra-long single-walled carbon nano tubes (ULSWCNTs) before and after additional chemical functionalization were seeded with macrophage cell culture. Prior to biological testing, the CNTs were subjected to dispersion process with the use of phosphate buffered solution (PBS) and PBS containing surfactant (Tween 20) or dimethyl sulfoxide (DMSO). The results indicate that the cells interaction with an individual nano tube is entirely different as compared to CNTs in the form of aggregate. The presence of the surfactant favors the CNTs dispersion in culture media and facilitates phagocytosis process, while it has disadvantageous influence on cells morphology. The cells phagocytosis is a more effective for MWCNTs and SWCNHs after their chemical functionalization. Moreover, these nano tubes were well dispersed in culture media without using DMSO or surfactant. The functionalized carbon nano tubes were easily dispersed in pure PBS and seeded with cells

  1. High-strength porous carbon and its multifunctional applications

    Science.gov (United States)

    Wojtowicz, Marek A; Rubenstein, Eric P; Serio, Michael A; Cosgrove, Joseph E

    2013-12-31

    High-strength porous carbon and a method of its manufacture are described for multifunctional applications, such as ballistic protection, structural components, ultracapacitor electrodes, gas storage, and radiation shielding. The carbon is produced from a polymer precursor via carbonization, and optionally by surface activation and post-treatment.

  2. Corrigendum to Photo catalytic Oxidation of Trichloroethylene in Water Using a Porous Ball of Nano-Zn O and Nano clay Composite

    International Nuclear Information System (INIS)

    Bak, S. A.; Song, M. S.; Nam, I.T.; Lee, W.G.

    2015-01-01

    In the published paper entitled Photo catalytic Oxidation of Trichloroethylene in Water Using a Porous Ball of Nano-Zn O and Nano clay Composite [1], we mistakenly used Laponite in our paper. The corrected name is Laponite (BYK Corporations products). So we are making some changes from Laponite to Laponite (BYK Corporations products) in our paper.

  3. Design and Fabrication of Carbon Nano tube for Medical Application

    International Nuclear Information System (INIS)

    Azniza Abas; Nuzaihan, M.N.; Hafiza, N.; Nazwa, T.

    2011-01-01

    Carbon nano tubes or known as CNTs are allotropes of carbon with a cylindrical nano structure. They exhibit extraordinary strength and unique electrical properties, and are efficient thermal conductors [1]. Due to its ordinary properties this research will based on BIOSENSOR device. Normally these CNTs biosensor are based on an enzyme catalyzed reaction that will produce either electrons or protons. In particular, it is useful in genetic profiling of human diseases, which includes in identifying genes that are expressed in certain diseases such as cancer [2]. This research will based on design and fabricate sensor or device using carbon nano tube and integrate carbon nano tube (CNTs) onto wafer using combination of dichlorophosphate and nano manipulation. Carbon nano tubes device mask are design using AUTOCAD software; there is four mask involved, first mask is Gate Formation,second mask is insulation layer third mask is source and drain and final mask forth mask is used as test channel. For fabrication and optimization of biosensor using carbon nano tube CNT that will be involve both microfabrication and nano fabrication. This process will involve conventional photolithography process, electron beam evaporator, thermal oxidation and wet etching process. To inspect and characterize carbon nano tube electrical properties it will involve tools such as SEM, AFM, Dielectric Analyzer, IV-CV and Semiconductor Parametric Analyzer system. This inspection is very important to produce a perfect profile to produce a good biosensor based on carbon nano tube structure. Preparation of various samples for testing functionality of the device this various samples and conditions will be done to ensure the detection is precise. Conductivity and capacitance effect will be tested electrically to detect the hybridization of the sample. (author)

  4. Nanoparticle tracers in calcium carbonate porous media

    KAUST Repository

    Li, Yan Vivian

    2014-07-15

    Tracers are perhaps the most direct way of diagnosing subsurface fluid flow pathways for ground water decontamination and for natural gas and oil production. Nanoparticle tracers could be particularly effective because they do not diffuse away from the fractures or channels where flow occurs and thus take much less time to travel between two points. In combination with a chemical tracer they can measure the degree of flow concentration. A prerequisite for tracer applications is that the particles are not retained in the porous media as the result of aggregation or sticking to mineral surfaces. By screening eight nanoparticles (3-100 nm in diameter) for retention when passed through calcium carbonate packed laboratory columns in artificial oil field brine solutions of variable ionic strength we show that the nanoparticles with the least retention are 3 nm in diameter, nearly uncharged, and decorated with highly hydrophilic polymeric ligands. The details of these column experiments and the tri-modal distribution of zeta potential of the calcite sand particles in the brine used in our tests suggests that parts of the calcite surface have positive zeta potential and the retention of negatively charged nanoparticles occurs at these sites. Only neutral nanoparticles are immune to at least some retention. © 2014 Springer Science+Business Media.

  5. Surface structure and adsorption properties of ultrafine porous carbon fibers

    International Nuclear Information System (INIS)

    Song Xiaofeng; Wang Ce; Zhang Dejiang

    2009-01-01

    Ultrafine porous carbon fibers (UPCFs) were successfully synthesized by chemical activation of electrospun polyacrylonitrile fibers. In the current approach, potassium hydroxide was adopted as activation reagent. UPCFs were systematically evaluated by scanning electron microscope and nitrogen adsorption. The mass ratio of potassium hydroxide to preoxidized fibers, activation temperature and activation time are crucial for producing high quality UPCFs. The relationships between porous structure and process parameters are explored. UPCFs were applied as adsorbent for nitrogen monoxide to be compared with commercial porous carbon fibers.

  6. Effect of nano Cu coating on porous Si prepared by acid etching Al-Si alloy powder

    International Nuclear Information System (INIS)

    Li, Chunli; Zhang, Ping; Jiang, Zhiyu

    2015-01-01

    As a promising anode material for lithium ion battery, nano-Cu coated porous Si powder was fabricated through two stages: first, preparation of porous nano Si fibers by acid-etching Al-Si alloy powder; second, modified by nano-Cu particles using an electroless plating method. The nano-Cu particles on the surface of nano-Si fibers, not only increase the conductivity of material, but also inhibit the fuse process between nano Si fibers during charge/discharge cycling process, resulting in increased cycling stability of the material. In 1 M LiPF 6 /EC: DMC (1:1) + 1.5 wt% VC solution at current density of 200 mA g −1 , the 150th discharge capacity of nano-Cu coated porous Si electrode was 1651 mAh g −1 with coulombic efficiency of 99%. As anode material for lithium ion battery, nano-Cu coated porous Si nano fiber material is easier to prepare, costs less, and produces higher performance, representing a promising approach for high energy lithium ion battery application

  7. Single-layer graphene-assembled 3D porous carbon composites with PVA and Fe₃O₄ nano-fillers: an interface-mediated superior dielectric and EMI shielding performance.

    Science.gov (United States)

    Rao, B V Bhaskara; Yadav, Prasad; Aepuru, Radhamanohar; Panda, H S; Ogale, Satishchandra; Kale, S N

    2015-07-28

    In this study, a novel composite of Fe3O4 nanofiller-decorated single-layer graphene-assembled porous carbon (SLGAPC) with polyvinyl alcohol (PVA) having flexibility and a density of 0.75 g cm(-3) is explored for its dielectric and electromagnetic interference (EMI) response properties. The composite is prepared by the solution casting method and its constituents are optimized as 15 wt% SLGAPC and 20 wt% Fe3O4 through a novel solvent relaxation nuclear magnetic resonance experiment. The PVA-SLGAPC-Fe3O4 composite shows high dielectric permittivity in the range of 1 Hz-10 MHz, enhanced by a factor of 4 as compared to that of the PVA-SLGAPC composite, with a reduced loss by a factor of 2. The temperature dependent dielectric properties reveal the activation energy behaviour with reference to the glass transition temperature (80 °C) of PVA. The dielectric hysteresis with the temperature cycle reveals a remnant polarization. The enhanced dielectric properties are suggested to be the result of improvement in the localized polarization of the integrated interface system (Maxwell-Wagner-Sillars (MWS) polarization) formed by the uniform adsorption of Fe3O4 on the surface of SLGAPC conjugated with PVA. The EMI shielding property of the composite with a low thickness of 0.3 mm in the X-band (8.2-12.4 GHz) shows a very impressive shielding efficiency of ∼15 dB and a specific shielding effectiveness of 20 dB (g cm(-3))(-1), indicating the promising character of this material for flexible EMI shielding applications.

  8. Gas Permeation Characteristics across Nano-Porous Inorganic Membranes

    Directory of Open Access Journals (Sweden)

    M.R Othman, H. Mukhtar

    2012-10-01

    Full Text Available An overview of parameters affecting gas permeation in inorganic membranes is presented. These factors include membrane physical characteristics, operational parameters and gas molecular characteristics. The membrane physical characteristics include membrane materials and surface area, porosity, pore size and pore size distribution and membrane morphology. The operational parameters include feed flow rate and concentration, stage cut, temperature and pressure. The gas molecular characteristics include gas molecular weight, diameter, critical temperature, critical pressure, Lennard-Jones parameters and diffusion volumes. The current techniques of material characterization may require complementary method in describing microscopic heterogeneity of the porous ceramic media. The method to be incorporated in the future will be to apply a stochastic model and/or fractal dimension. Keywords: Inorganic membrane, surface adsorption, Knudsen diffusion, Micro-porous membrane, permeation, gas separation.

  9. Super-hierarchical porous carbons derived from mixed biomass wastes by a stepwise removal strategy for high-performance supercapacitors

    Science.gov (United States)

    Peng, Lin; Liang, Yeru; Dong, Hanwu; Hu, Hang; Zhao, Xiao; Cai, Yijing; Xiao, Yong; Liu, Yingliang; Zheng, Mingtao

    2018-02-01

    The synthesis and energy storage application of hierarchical porous carbons with size ranging from nano-to micrometres has attracted considerable attention all over the world. Exploring eco-friendly and reliable synthesis of hierarchical porous carbons for supercapacitors with high energy density and high power is still of ongoing challenge. In this work, we report the design and synthesis of super-hierarchical porous carbons with highly developed porosity by a stepwise removal strategy for high-rate supercapacitors. The mixed biomass wastes of coconut shell and sewage sludge are employed as raw material. The as-prepared super-hierarchical porous carbons present high surface areas (3003 m2 g-1), large pore volume (2.04 cm3 g-1), appropriate porosity, and outstanding electrochemical performance. The dependence of electrochemical performance on structural, textural, and functional properties of carbons engineered by various synthesis strategies is investigated in detail. Moreover, the as-assembled symmetrical supercapacitor exhibits high energy density of 25.4 Wh kg-1 at a power density of 225 W kg-1 and retains 20.7 Wh kg-1 even at a very high power of 9000 W kg-1. This work provides an environmentally benign strategy and new insights to efficiently regulate the porosity of hierarchical porous carbons derived from biomass wastes for energy storage applications.

  10. Mechanical and frictional behaviour of nano-porous anodised aluminium

    Energy Technology Data Exchange (ETDEWEB)

    Tsyntsaru, N., E-mail: tintaru@phys.asm.md [Institute of Applied Physics of ASM, 5 Academy str., Chisinau, MD 2028 (Moldova, Republic of); Kavas, B., E-mail: bkavas@ford.com.tr [Istanbul Technical University, Department of Metallurgical and Materials Engineering, 34469 Maslak (Turkey); Ford Otomotiv San A.S., Istanbul (Turkey); Sort, J., E-mail: jordi.sort@uab.cat [Institució Catalana de Recerca i Estudis Avançats (ICREA) and Departament de Física, Universitat Autònoma de Barcelona, E-08193 Bellaterra (Spain); Urgen, M., E-mail: urgen@itu.edu.tr [Istanbul Technical University, Department of Metallurgical and Materials Engineering, 34469 Maslak (Turkey); Celis, J.-P., E-mail: jean-pierre.celis@mtm.kuleuven.be [KU Leuven, Dept. MTM, Kasteelpark Arenberg 44, B-3001 (Belgium)

    2014-12-15

    The porous structure of anodic aluminium oxide (AAO) can be used in versatile applications such as a lubricant reservoir in self-lubricating systems. Such systems are subjected to biaxial loading, which can induce crack formation and propagation, ultimately leading to catastrophic mechanical failure. In this study, the mechanical and tribological behaviour of AAO, prepared from two different types of electrolytes (sulphuric and oxalic acids), are studied in detail. The electrolytic conditions are adjusted to render highly tuneable average pore diameters (between 16 and 75 nm), with porosity levels ranging from 9% to 65%. Well-ordered porous AAO are produced by two-step anodization at rather low temperatures. Mechanical properties, mainly hardness and Young's modulus, are investigated using nanoindentation. Both the porosity degree and the composition of the electrolytic baths used to prepare the AAO have an influence on the mechanical properties. Ball-on-flat configuration was used to estimate the tribological behaviour under dry conditions. No major cracks were observed by scanning electron microscopy, neither after indentation or fretting tests. In the running-in period of tribology experiments the pores were filled with debris. This was followed by the formation of a highly adherent tribolayer – a third body consisting of fine worn particles originated from both the sample and the counterbody. Pore diameter and porosity percentage are found to strongly affect hardness and Young's modulus, but they do not have a major effect on the frictional behaviour. - Highlights: • Well-ordered porous AAO with pore diameters between 16 and 75 nm were produced. • Porosity and composition of electrolytic baths influence the mechanical properties. • Ball-on-flat configuration was used in tribological testing under dry conditions. • Adherent tribolayer consisting of fine worn particles prevents AAO from cracking. • Testing parameters are moreover essential

  11. Deformation bands in porous carbonate grainstones: Field and laboratory observations

    NARCIS (Netherlands)

    Cilona, A.; Baud, P.; Tondi, E.; Agosta, F.; Vinciguerra, S.; Rustichelli, A.; Spiers, C.J.

    2012-01-01

    Recent field-based studies documented deformation bands in porous carbonates; these structures accommodate volumetric and/or shear strain by means of pore collapse, grain rotation and/or sliding. Microstructural observations of natural deformation bands in carbonates showed that, at advanced stages

  12. Heavy metal ion adsorption onto polypyrrole-impregnated porous carbon.

    Science.gov (United States)

    Choi, Moonjung; Jang, Jyongsik

    2008-09-01

    Polypyrrole-impregnated porous carbon was readily synthesized using vapor infiltration polymerization of pyrrole monomers. The results show that the functionalized polymer layer was successfully coated onto the pore surface of carbon without collapse of mesoporous structure. The modified porous carbon exhibited an improved complexation affinity for heavy metal ions such as mercury, lead, and silver ions due to the amine group of polypyrrole. The introduced polypyrrole layer could provide the surface modification to be applied for heavy metal ion adsorbents. Especially, polymer-impregnated porous carbon has an enhanced heavy metal ion uptake, which is 20 times higher than that of adsorbents with amine functional groups. Furthermore, the relationship between the coated polymer amount and surface area was also investigated in regard to adsorption capacity.

  13. Synthesis of Porous Carbon Monoliths Using Hard Templates.

    Science.gov (United States)

    Klepel, Olaf; Danneberg, Nina; Dräger, Matti; Erlitz, Marcel; Taubert, Michael

    2016-03-21

    The preparation of porous carbon monoliths with a defined shape via template-assisted routes is reported. Monoliths made from porous concrete and zeolite were each used as the template. The porous concrete-derived carbon monoliths exhibited high gravimetric specific surface areas up to 2000 m²·g -1 . The pore system comprised macro-, meso-, and micropores. These pores were hierarchically arranged. The pore system was created by the complex interplay of the actions of both the template and the activating agent as well. On the other hand, zeolite-made template shapes allowed for the preparation of microporous carbon monoliths with a high volumetric specific surface area. This feature could be beneficial if carbon monoliths must be integrated into technical systems under space-limited conditions.

  14. 6. international conference on Nano-technology in Carbon: from synthesis to applications of nano-structured carbon and related materials

    International Nuclear Information System (INIS)

    2004-01-01

    This is the sixth international conference sponsored this year by the French Carbon Group (GFEC), the European Research Group on Nano-tubes GDRE 'Nano-E', in collaboration with the British Carbon Group and the 'Institut des Materiaux Jean Rouxel' (local organizer). The aim of this conference is to promote carbon science in the nano-scale as, for example, nano-structured carbons, nano-tubes, nano-wires, fullerenes, etc. This conference is designed to introduce those with an interest in materials to current research in nano-technology and to bring together research scientists working in various disciplines in the broad area of nano-structured carbons, nano-tubes and fullerene-related nano-structures. Elemental carbon is the simplest exemplar of this nano-technology based on covalent bonding, however other systems (for example containing hetero-atoms) are becoming important from a research point of view, and provide alternative nano-materials with unique properties opening a broad field of applications. Nano-technology requires an understanding of these materials on a structural and textural point of view and this will be the central theme. This year the conference will feature sessions on: S1. Control and synthesis of nano-materials 1.1 Nano-structured carbons: pyrolysis of polymers, activation, templates,... 1.2 Nano-tubes: Catalytic method, HiPCO, graphite vaporization, electrolysis,... 1.3 Fullerenes S2. Chemistry of carbon nano-materials 2.1 Purification of carbon nano-tubes 2.2 Functionalization - Self-assembling S3. Structural characterization S4. Theory and modelling S5. Relationship between structure and properties S6. Applications Water and air purification, Gas and energy storage, Composite materials, Field emission, Nano-electronics, Biotechnology,... S7. Environmental impact. Only one paper concerning carbon under irradiation has been added to the INIS database. (authors)

  15. Light hydrogen isotopes in the single - walled carbon nano tube

    International Nuclear Information System (INIS)

    Khugaev, A.V.; Sultanov, R.A.; Guster, D.

    2007-01-01

    Full text: Progress of our understanding of the molecular hydrogen behavior in the nano tube interior open an intriguing possibility for the applications of these knowledge's to the solution of the hydrogen storage problem and light isotopes gas selectivity. That can strongly change the situation at the energy production in the world and completely change our civil life. These investigations underline the influence of the quantum effects on the properties of molecular hydrogen in the nano tube interior and it leads to the pure quantum-mechanical reformulation of the problem for the hydrogen behavior inside carbon nano tube as a problem of molecular quantum system behavior in the external field induced by the regular nano tube surface. In the present paper the molecular hydrogen behavior in the carbon nano tube was considered in the simple quantum mechanical manner. The main attention was paid to the investigation of the quantum sieving selectivity in the dependence of nano tube composition, radius and symmetry properties. For the interaction potential between hydrogen and nano tube surface was taken some phenomenological LJ(12,6) - (Lennard - Jones) potential and the external field induced by the nano tube in its interior is considered as a simple sum over the all nano tube carbon atoms. Influence of the structure of rotation (vibration) spectrum of the energy levels of diatomic molecules, such as H 2 , HD and D 2 on the final results and finite size of the nano tube along the axis of symmetry, its boundary effects is discussed in details. Thermal oscillations of nano tube surface were considered separately in the dependence of the temperature gradient along of the axis of symmetry

  16. Method for nano-pumping using carbon nanotubes

    Science.gov (United States)

    Insepov, Zeke [Darien, IL; Hassanein, Ahmed [Bolingbrook, IL

    2009-12-15

    The present invention relates generally to the field of nanotechnology, carbon nanotubes and, more specifically, to a method and system for nano-pumping media through carbon nanotubes. One preferred embodiment of the invention generally comprises: method for nano-pumping, comprising the following steps: providing one or more media; providing one or more carbon nanotubes, the one or more nanotubes having a first end and a second end, wherein said first end of one or more nanotubes is in contact with the media; and creating surface waves on the carbon nanotubes, wherein at least a portion of the media is pumped through the nanotube.

  17. Electrode fabrication for Lithium-ion batteries by intercalating of carbon nano tubes inside nano metric pores of silver foam

    International Nuclear Information System (INIS)

    Khoshnevisan, B.

    2011-01-01

    Here there is an on effort to improve working electrode (Ag + carbon nano tubes) preparation for Li-Ion batteries applications. Nano scaled silver foam with high specific area has been employed as a frame for loading carbon nano tubes by electrophoretic deposition method. In this ground, the prepared electrodes show a very good stability and also charge-discharge cycles reversibility.

  18. Electric double layer capacitance on hierarchical porous carbons in an organic electrolyte

    OpenAIRE

    Yamada, Hirotoshi; Moriguchi, Isamu; Kudo, Tetsuichi

    2008-01-01

    Nanoporous carbons were prepared by using colloidal crystal as a template. Nitrogen adsorption/desorption isotherms and transmission electron microscope images revealed that the porous carbons exhibit hierarchical porous structures with meso/macropores and micropores. Electric double layer capacitor performance of the porous carbons was investigated in an organic electrolyte of 1 M LiClO4 in propylene carbonate and dimethoxy ethane. The hierarchical porous carbons exhibited large specific dou...

  19. Carbon nano-tubes - what risks, what prevention?

    International Nuclear Information System (INIS)

    Ricaud, Myriam; Lafon, Dominique; Roos, Frederique

    2007-01-01

    Carbon nano-tubes are arousing considerable interest in both the research world and industry because of their exceptional intrinsic properties and dimensional characteristics. Health risks of nano-tubes have been little studied, although the general public is already aware of their existence on account of their numerous promising applications. Existing, sometimes extremely brief, publications only reveal insufficient data for assessing risks sustained due to carbon nano-tube exposure. Yet, the great interest aroused by these new chemicals would indicate strongly that the number of exposed workers will increase over the coming years. It therefore appears essential to review not only the characteristics and applications of carbon nano-tubes, but also the prevention means to be implemented during their handling. We recommend application of the principle of precaution and measures to keep the exposure level as low as possible until the significance of occupational exposure and the corresponding human health risks are better known and have been assessed. (authors)

  20. Preparation of porous carbon particle with shell/core structure

    Directory of Open Access Journals (Sweden)

    2007-05-01

    Full Text Available Porous carbon particles with a shell/core structure have been prepared successfully by controlled precipitation of the polymer from droplets of oil-in-water emulsion, followed by curing and carbonization. The droplets of the oil phase are composed of phenolic resin (PFR, a good solvent (ethyl acetate and porogen (Poly(methyl methacrylate, PMMA. The microstructure was characterized in detail by scanning electron microscopy (SEM, transmission electron microscopy (TEM, nitrogen adsorption, and thermo gravimetric analysis (TGA. The obtained carbon particles have a capsular structure with a microporous carbon shell and a mesoporous carbon core. The BET surface area and porous volume are calculated to be 499 m2g-1 and 0.56 cm3g-1, respectively. The effects of the amount of porogen (PMMA, co-solvent (acetone and surfactant on the resultant structure were studied in detail.

  1. Omega-3 PUFA concentration by a novel PVDF nano-composite membrane filled with nano-porous silica particles.

    Science.gov (United States)

    Ghasemian, Samaneh; Sahari, Mohammad Ali; Barzegar, Mohsen; Ahmadi Gavlighi, Hasan

    2017-09-01

    In this study, polyvinylidene fluoride (PVDF) and nano-porous silica particle were used to fabricate an asymmetric nano-composite membrane. Silica particles enhanced the thermal stability of PVDF/SiO 2 membranes; increasing the decomposition temperature from 371°C to 408°C. Cross sectional morphology showed that silica particles were dispersed in polymer matrix uniformly. However, particle agglomeration was found at higher loading of silica (i.e., 20 by weight%). The separation performance of nano-composite membranes was also evaluated using the omega-3 polyunsaturated fatty acids (PUFA) concentration at a temperature and pressure of 30°C and 4bar, respectively. Silica particle increased the omega-3PUFA concentration from 34.8 by weight% in neat PVDF to 53.9 by weight% in PVDF with 15 by weight% of silica. Moreover, PVDF/SiO 2 nano-composite membranes exhibited enhanced anti-fouling property compared to neat PVDF membrane. Fouling mechanism analysis revealed that complete pore blocking was the predominant mechanism occurring in oil filtration. The concentration of omega-3 polyunsaturated fatty acids (PUFA) is important in the oil industries. While the current methods demand high energy consumptions in concentrating the omega-3, membrane separation technology offers noticeable advantages in producing pure omega-3 PUFA. Moreover, concentrating omega-3 via membrane separation produces products in the triacylglycerol form which possess better oxidative stability. In this work, the detailed mechanisms of fouling which limits the performance of membrane separation were investigated. Incorporating silica particles to polymeric membrane resulted in the formation of mixed matrix membrane with improved anti-fouling behaviour compared to the neat polymeric membrane. Hence, the industrial potential of membrane processing to concentrate omega-3 fatty acids is enhanced. Copyright © 2017. Published by Elsevier Ltd.

  2. Supercooling and cold energy storage characteristics of nano-media in ball-packed porous structures

    Directory of Open Access Journals (Sweden)

    Zhao Qunzhi

    2015-04-01

    Full Text Available The presented experiments aimed to study the supercooling and cold-energy storage characteristics of nanofluids and water-based nano-media in ball-packed porous structures (BPS. Titanium dioxide nanoparticles (TiO2 NPs measuring 20nm and 80nm were used as additives and sodium dodecyl benzene sulphonate (SDBS was used as anionic surfactant. The experiments used different concentrations of nanofluid, distilled with BPS of different spherical diameter and different concentrations of nano-media, and were conducted 20 times. Experimental results of supercooling were analysed by statistical methods. Results show that the average and peak supercooling degrees of nanofluids and nano-media in BPS are lower than those of distilled water. For the distilled water in BPS, the supercooling degree decreases on the whole with the decrease of the ball diameter. With the same spherical diameter (8mm of BPS, the supercooling degree of TiO2 NPs measuring 20nm is lower than the supercooling degree of distilled water in BPS. Step-cooling experiments of different concentrations of nanofluids and nano-media in BPS were also conducted. Results showed that phase transition time is reduced because of the presence of TiO2 NPs. The BPS substrate and the NPs enhance the heat transfer. Distilled water with a porous solid base and nanoparticles means the amount of cold-energy storage increases and the supercooling degree and the total time are greatly reduced. The phase transition time of distilled water is about 3.5 times that of nano-media in BPS.

  3. Nitrogen-doped hierarchical porous carbon materials prepared from meta-aminophenol formaldehyde resin for supercapacitor with high rate performance

    International Nuclear Information System (INIS)

    Zhou, Jin; Zhang, Zhongshen; Xing, Wei; Yu, Jing; Han, Guoxing; Si, Weijiang; Zhuo, Shuping

    2015-01-01

    Graphical abstract: N-doped hierarchical porous carbons with high rate capacitive performance are prepared by a combination method of nano-SiO 2 template/KOH activation. - Highlights: • A mass produced nano-SiO 2 is used to prepared hierarchical porous carbon. • N-doped hierarchical porous carbon materials are easily prepared. • The NHPCs materials exhibit a very high capacitance of up to 260.5 F g −1 . • The NHPC-800 sample shows very high rate capability. • Hierarchical porosity and N-doping synergistically enhances the whole capacitance. - Abstract: In this work, nitrogen-doped hierarchical porous carbon materials (NHPCs) are prepared by a two-step method combined of a hard template process and KOH-activation treatment. Low cost and large-scale commercial nano-SiO 2 are used as a hard template. The hierarchical porosity, structure and nitrogen-doped surface chemical properties are proved by a varies of means, such as scanning electron microscopy, transition electron microscopy, N 2 sorption, Raman spectroscopy, X-ray diffraction and X-ray photoelectron spectroscopy. When the prepared NHPCs materials are used as the electrode materials for supercapacitors in KOH electrolyte, they exhibit very high specific capacitance, good power capability and excellent cyclic stability. NHPC-800 carbon shows a high capacitance of 114.0 F g −1 at the current density of 40 A g −1 , responding to a high energy and power densities of 4.0 Wh kg −1 and 10 000 W kg −1 , and a very short drain time of 1.4 s. The excellent capacitive performance may be due to the synergistic effect of the hierarchical porosity, high effective surface area and heteroatom doping, resulting in both electrochemical double layer and Faradaic capacitance contributions

  4. Hyper-elastic modeling and mechanical behavior investigation of porous poly-D-L-lactide/nano-hydroxyapatite scaffold material.

    Science.gov (United States)

    Han, Quan Feng; Wang, Ze Wu; Tang, Chak Yin; Chen, Ling; Tsui, Chi Pong; Law, Wing Cheung

    2017-07-01

    Poly-D-L-lactide/nano-hydroxyapatite (PDLLA/nano-HA) can be used as the biological scaffold material in bone tissue engineering as it can be readily made into a porous composite material with excellent performance. However, constitutive modeling for the mechanical response of porous PDLLA/nano-HA under various stress conditions has been very limited so far. In this work, four types of fundamental compressible hyper-elastic constitutive models were introduced for constitutive modeling and investigation of mechanical behaviors of porous PDLLA/nano-HA. Moreover, the unitary expressions of Cauchy stress tensor have been derived for the PDLLA/nano-HA under uniaxial compression (or stretch), biaxial compression (or stretch), pure shear and simple shear load by using the theory of continuum mechanics. The theoretical results determined from the approach based on the Ogden compressible hyper-elastic constitutive model were in good agreement with the experimental data from the uniaxial compression tests. Furthermore, this approach can also be used to predict the mechanical behaviors of the porous PDLLA/nano-HA material under the biaxial compression (or stretch), pure shear and simple shear. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Facile synthesis of nano cauliflower and nano broccoli like hierarchical superhydrophobic composite coating using PVDF/carbon soot particles via gelation technique.

    Science.gov (United States)

    Sahoo, Bichitra Nanda; Balasubramanian, Kandasubramanian

    2014-12-15

    We have elucidated a cost effective fabrication technique to produce superhydrophobic polyvinylidene fluoride (PVDF/DMF/candle soot particle and PVDF/DMF/camphor soot particle composite) porous materials. The water repellent dry composite was formed by the interaction of non-solvent (methanol) into PVDF/carbon soot particles suspension in N,N-dimethylformamide (DMF). It is seen that longer quenching time effectively changes the surface morphology of dry composites. The nano broccoli like hierarchical microstructure with micro or nano scaled roughen surface was obtained for PVDF/DMF/camphor soot particle, which reveals water contact angle of 172° with roll off angle of 2°. However, composite coating of PVDF/DMF/candle soot particle shows nano cauliflower like hierarchical, which illustrates water contact angle of 169° with roll off angle of 3°. To elucidate the enhancement of water repellent property of PVDF composites, we further divulge the evolution mechanism of nano cauliflower and nano broccoli structure. In order to evaluate the water contact angle of PVDF composites, surface diffusion of water inside the pores is investigated. Furthermore, the addition of small amount of carbon soot particles in composite not only provides the crystallization of PVDF, but also leads to dramatical amendment of surface morphology which increases the surface texture and roughness for superhydrophobicity. Copyright © 2014 Elsevier Inc. All rights reserved.

  6. Metastable carbon in two chondritic porous interplanetary dust particles

    International Nuclear Information System (INIS)

    Rietmeijer, F.J.M.; Mackinnon, I.D.R.

    1987-01-01

    An analytical electron microscope study is presented on carbonaceous material in two chondritic porous aggregates, W7029* A and W7010* A2, from the Johnson Space Center Cosmic Dust Collection. The finding of well-ordered carbon-2H (lonsdaleite) in the two aggregates suggests that a record of hydrocarbon carbonization may be preserved in these materials. This carbon is a metastable phase resulting from hydrous pyrolysis below 300-350 0 C and may be a precursor to poorly graphitized carbons in primitive extra terrestrial materials. (UK)

  7. Wireless desalination using inductively powered porous carbon electrodes

    NARCIS (Netherlands)

    Kuipers, J.; Porada, S.

    2013-01-01

    Water desalination by capacitive deionization (CDI) uses electrochemical cell pairs formed of porous carbon electrodes, which are brought in contact with the water that must be desalinated. Upon applying a cell voltage or current between the electrodes, ions are electrosorbed and water is produced

  8. Metastable carbon in two chondritic porous interplanetary dust particles

    International Nuclear Information System (INIS)

    Rietmeijer, F.J.M.; Mackinnon, I.D.R.

    1986-01-01

    An understanding of carbonaceous matter in primitive extraterrestrial materials is an essential component of studies on dust evolution in the interstellar medium and the early history of the Solar System. Analytical Electron Microscopy (AEM) on carbonaceous material in two Chondritic Porous (CP) aggregrates is presented. The study suggests that a record of hydrocarbon carbonization may also be preserved in these materials

  9. Porous graphitic materials obtained from carbonization of organic ...

    Indian Academy of Sciences (India)

    features such as pore diameter, hierarchical porous archi- tectures, surface ... bon xerogels seem to be promising candidates for liquid ... co-solvent to increase the solubility of furfural, whilst the .... 100 nm, thus Vt means the total volume of pores below c.a. ..... Wang Z, Zhang X, Liu X, Lv M, Yang K and Meng J 2011 Carbon.

  10. Hydrogen storage in porous carbons: modelling and performance improvements

    International Nuclear Information System (INIS)

    Pellenq, R.J.M.; Maresca, O.; Marinelli, F.; Duclaux, L.; Azais, P.; Conard, J.

    2006-01-01

    In this work, we aim at exploring using ab initio calculations, the various ways allowing for an efficient hydrogen docking in carbon porous materials. Firstly, the influence of surface curvature on the chemisorption of atomic hydrogen is considered. Then it is shown that electro-donor elements such as lithium or potassium used as dopant of the carbon substrate induce a strong physi-sorption for H 2 , allowing its storage at ambient temperature under moderate pressure. (authors)

  11. In vitro degradation of porous nano-hydroxyapatite/collagen/PLLA scaffold reinforced by chitin fibres

    International Nuclear Information System (INIS)

    Li Xiaoming; Feng Qingling; Cui Fuzhai

    2006-01-01

    In this paper, a novel porous scaffold for bone tissue engineering was prepared with nano-hydroxyapatite/collagen/Poly-L-lactic acid (PLLA) composite reinforced by chitin fibres. To enhance the strength of the scaffold further, PLLA was linked with chitin fibres by Dicyclohexylcarbodimide (DCC). The structures of the reinforced scaffold with and without linking were characterized by Scanning Electron Microscopy (SEM). The chemical characteristics of the chitin fibres with and without linking were evaluated by Fourier-transformed infrared (FTIR) spectroscopy. The mechanical performance during degradation in vitro was investigated. The results indicated that the nano-hydroxyapatite/collagen/PLLA composite reinforced by chitin fibres with linking kept better mechanical properties than that of the composite without linking. These results denoted that the stronger interfacial bonding strength of the scaffold with linking could decrease the degradation rate in vitro. The reinforced composite with the link-treatment can be severed as a scaffold for bone tissue engineering

  12. Preparation and cellular response of porous A-type carbonated hydroxyapatite nanoceramics

    Energy Technology Data Exchange (ETDEWEB)

    Li Bo, E-mail: Leewave@126.com [Institute of Biomaterials and Living Cell Imaging Technology, School of Metallurgy and Materials Engineering, Chongqing University of Science and Technology, Chongqing 401331 (China) and National Engineering Research Center for Biomaterials, Sichuan University, Chengdu 610064 (China); Liao Xiaoling [Institute of Biomaterials and Living Cell Imaging Technology, School of Metallurgy and Materials Engineering, Chongqing University of Science and Technology, Chongqing 401331 (China); Zheng Li [National Engineering Research Center for Biomaterials, Sichuan University, Chengdu 610064 (China); He Huawei [Department of Prosthodontics, Beijing Stomatological Hospital, Capital Medical University, Beijing, 100050 (China); Wang Hong [National Engineering Research Center for Biomaterials, Sichuan University, Chengdu 610064 (China); Fan Hongsong, E-mail: hsfan68@hotmail.com [National Engineering Research Center for Biomaterials, Sichuan University, Chengdu 610064 (China); Zhang Xingdong [National Engineering Research Center for Biomaterials, Sichuan University, Chengdu 610064 (China)

    2012-05-01

    Microwave sintering using the activated carbon as embedding material was applied in preparation of porous A-type carbonated hydroxyapatite ceramics with nano(nCHA) and submicron (mCHA) structure. By examining the linear shrinkages and the compressive strengths of samples at different temperatures, a suitable microwave sintering temperature was achieved. The microwave sintering method was successfully used to prepare A-type CHA with nano or submicron structure, and the mechanism of the formation of A-type carbonate groups was discussed also. Compared with the samples prepared by the conventional sintering method (mHA), the nCHA bioceramics synthesized by the microwave sintering approach had smaller grain size and more uniform microstructure, and showed a compressive strength similar to the conventional samples. In vitro dissolution test proved that nCHA exhibits better degradation property in comparison to pure HA. Rat osteoblasts were cultured with nCHA, mCHA and mHA to evaluate their biocompatibility, and nCHA showed significant enhancement of cells in attachment, proliferation and differentiation. In conclusion, carbonate groups can be easily introduced to HA crystal structure using the activated carbon as embedding material, and microwave sintering is an effective and simple method in preparing A-type CHA with a nanostructure. Results from this in vitro biological study suggest that porous A-type carbonated hydroxyapatite nanoceramics may be a much better candidate for clinical use in terms of bioactivity. - Highlights: Black-Right-Pointing-Pointer We prepared porous A-type carbonated hydroxyapatite nanoceramics with microwave sintering. Black-Right-Pointing-Pointer We examined physico-chemical characterization and osteoblast response. Black-Right-Pointing-Pointer The nanoceramics have a comparable compressive strength to samples with conventional sintering method. Black-Right-Pointing-Pointer The nanoceramics enhance degradation property, osteoblast

  13. Synthesis, Properties, and Applications of Low-Dimensional Carbon-Related Nano materials

    International Nuclear Information System (INIS)

    Mostofizadeh, A.; Li, Y.; Song, B.; Huang, Y.; Mostofizadeh, A.

    2011-01-01

    In recent years, many theoretical and experimental studies have been carried out to develop one of the most interesting aspects of the science and nano technology which is called carbon-related nano materials. The goal of this paper is to provide a review of some of the most exciting and important developments in the synthesis, properties, and applications of low-dimensional carbon nano materials. Carbon nano materials are formed in various structural features using several different processing methods. The synthesis techniques used to produce specific kinds of low-dimensional carbon nano materials such as zero-dimensional carbon nano materials (including fullerene, carbon-encapsulated metal nanoparticles, nano diamond, and onion-like carbons), one-dimensional carbon nano materials (including carbon nano fibers and carbon nano tubes), and two-dimensional carbon nano materials (including graphene and carbon nano walls) are discussed in this paper. Subsequently, the paper deals with an overview of the properties of the mainly important products as well as some important applications and the future outlooks of these advanced nano materials.

  14. Investigation of bioactivity and cell effects of nano-porous sol–gel derived bioactive glass film

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Zhijun, E-mail: mokuu@zju.edu.cn [State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou, 510640 (China); Ji, Huijiao [College of Life Science, Zhejiang University, Hangzhou, 310028 (China); Hu, Xiaomeng [School of Materials Science and Engineering, South China University of Technology, Guangzhou, 510640 (China); Teng, Yu [State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou, 510640 (China); Zhao, Guiyun; Mo, Lijuan; Zhao, Xiaoli [College of Life Science, Zhejiang University, Hangzhou, 310028 (China); Chen, Weibo [School of Materials Science and Engineering, South China University of Technology, Guangzhou, 510640 (China); Qiu, Jianrong, E-mail: qjr@scut.edu.cn [State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou, 510640 (China); Zhang, Ming, E-mail: zhangming201201@126.com [College of Life Science, Zhejiang University, Hangzhou, 310028 (China)

    2013-11-01

    In orthopedic surgery, bioactive glass film coating is extensively studied to improve the synthetic performance of orthopedic implants. A lot of investigations have confirmed that nano-porous structure in bioactive glasses can remarkably improve their bioactivity. Nevertheless, researches on preparation of nano-porous bioactive glasses in the form of film coating and their cell response activities are scarce. Herein, we report the preparation of nano-porous bioactive glass film on commercial glass slide based on a sol–gel technique, together with the evaluation of its in vitro bioactivity through immersion in simulated body fluid and monitoring the precipitation of apatite-like layer. Cell responses of the samples, including attachment, proliferation and osteogenic differentiation, were also investigated using BMSCS (bone marrow derived mesenchymal stem cells) as a model. The results presented here provide some basic information on structural influence of bioactive glass film on the improvement of bioactivity and cellular effects.

  15. Investigation of bioactivity and cell effects of nano-porous sol-gel derived bioactive glass film

    Science.gov (United States)

    Ma, Zhijun; Ji, Huijiao; Hu, Xiaomeng; Teng, Yu; Zhao, Guiyun; Mo, Lijuan; Zhao, Xiaoli; Chen, Weibo; Qiu, Jianrong; Zhang, Ming

    2013-11-01

    In orthopedic surgery, bioactive glass film coating is extensively studied to improve the synthetic performance of orthopedic implants. A lot of investigations have confirmed that nano-porous structure in bioactive glasses can remarkably improve their bioactivity. Nevertheless, researches on preparation of nano-porous bioactive glasses in the form of film coating and their cell response activities are scarce. Herein, we report the preparation of nano-porous bioactive glass film on commercial glass slide based on a sol-gel technique, together with the evaluation of its in vitro bioactivity through immersion in simulated body fluid and monitoring the precipitation of apatite-like layer. Cell responses of the samples, including attachment, proliferation and osteogenic differentiation, were also investigated using BMSCS (bone marrow derived mesenchymal stem cells) as a model. The results presented here provide some basic information on structural influence of bioactive glass film on the improvement of bioactivity and cellular effects.

  16. Preparation, Characterization, and Modeling of Carbon Nano fiber/Epoxy Nano composites

    International Nuclear Information System (INIS)

    Sun, L.H.; Yang, Z.G.; Ounaies, Z.; Whalen, C.A.; Gao, X.L.

    2011-01-01

    There is a lack of systematic investigations on both mechanical and electrical properties of carbon nano fiber (CNF)-reinforced epoxy matrix nano composites. In this paper, an in-depth study of both static and dynamic mechanical behaviors and electrical properties of CNF/epoxy nano composites with various contents of CNFs is provided. A modified Halpin-Tsai equation is used to evaluate the Young's modulus and storage modulus of the nano composites. The values of Young's modulus predicted using this method account for the effect of the CNF agglomeration and fit well with those obtained experimentally. The results show that the highest tensile strength is found in the epoxy nano composite with a 1.0 wt % CNFs. The alternate-current (AC) electrical properties of the CNF/epoxy nano composites exhibit a typical insulator-conductor transition. The conductivity increases by four orders of magnitude with the addition of 0.1 wt % (0.058 vol %) CNFs and by ten orders of magnitude for nano composites with CNF volume fractions higher than 1.0 wt % (0.578 vol %). The percolation threshold (i.e., the critical CNF volume fraction) is found to be at 0.057 vol %.

  17. Flame synthesis of carbon nano onions using liquefied petroleum gas without catalyst

    International Nuclear Information System (INIS)

    Dhand, Vivek; Prasad, J. Sarada; Rao, M. Venkateswara; Bharadwaj, S.; Anjaneyulu, Y.; Jain, Pawan Kumar

    2013-01-01

    Densely agglomerated, high specific surface area carbon nano onions with diameter of 30–40 nm have been synthesized. Liquefied petroleum gas and air mixtures produced carbon nano onions in diffusion flames without catalyst. The optimized oxidant to fuel ratio which produces carbon nano onions has been found to be 0.1 slpm/slpm. The experiment yielded 70% pure carbon nano onions with a rate of 5 g/h. X-ray diffraction, high-resolution electron microscopy and Raman spectrum reveal the densely packed sp 2 hybridized carbon with (002) semi-crystalline hexagonal graphite reflection. The carbon nano onions are thermally stable up to 600 °C. - Highlights: ►Flame synthesized carbon nano onions with 30–40 nm diameters. ►LPG/air, diffusion type flame used in absence of catalyst to produce nano onions. ►Carbon nano onion production rate is 5 g/hr and with 70% purity.

  18. High performance supercapacitor using catalysis free porous carbon nanoparticles

    International Nuclear Information System (INIS)

    Ali, Gomaa A M; Manaf, Shoriya Aruni Bt Abdul; Chong, Kwok Feng; Hegde, Gurumurthy; Kumar, Anuj

    2014-01-01

    Very high supercapacitance values are obtained using catalyst free porous carbon nanoparticles (PCNs). The obtained PCNs have a porous structure with fine particles 35 nm in size. The specific capacitance of PCNs is 343 F g −1 and 309 F g −1 at 5 mV s −1 and 0.06 A g −1 , respectively. PCNs shows a high cyclic stability of about 90% and high columbic efficiency of 95% over 2500 cycles at 1 A g −1 . Impedance spectra show low resistance of PCNs, supporting their suitability for supercapacitor electrode application. (paper)

  19. Computational materials chemistry for carbon capture using porous materials

    International Nuclear Information System (INIS)

    Sharma, Abhishek; Malani, Ateeque; Huang, Runhong; Babarao, Ravichandar

    2017-01-01

    Control over carbon dioxide (CO 2 ) release is extremely important to decrease its hazardous effects on the environment such as global warming, ocean acidification, etc. For CO 2 capture and storage at industrial point sources, nanoporous materials offer an energetically viable and economically feasible approach compared to chemisorption in amines. There is a growing need to design and synthesize new nanoporous materials with enhanced capability for carbon capture. Computational materials chemistry offers tools to screen and design cost-effective materials for CO 2 separation and storage, and it is less time consuming compared to trial and error experimental synthesis. It also provides a guide to synthesize new materials with better properties for real world applications. In this review, we briefly highlight the various carbon capture technologies and the need of computational materials design for carbon capture. This review discusses the commonly used computational chemistry-based simulation methods for structural characterization and prediction of thermodynamic properties of adsorbed gases in porous materials. Finally, simulation studies reported on various potential porous materials, such as zeolites, porous carbon, metal organic frameworks (MOFs) and covalent organic frameworks (COFs), for CO 2 capture are discussed. (topical review)

  20. Morphologies and wetting properties of copper film with 3D porous micro-nano hierarchical structure prepared by electrochemical deposition

    International Nuclear Information System (INIS)

    Wang, Hongbin; Wang, Ning; Hang, Tao; Li, Ming

    2016-01-01

    Highlights: • A 3D porous micro-nano hierarchical structure Cu films were prepared. • The evolution of morphology and wettability with deposition time was reported. • The effects of EDA on the microscopic morphology were revealed. • A high contact angle of 162.1° was measured when deposition time is 5 s. • The mechanism of super-hydrophobicity was illustrated by two classical models. - Abstract: Three-dimensional porous micro-nano hierarchical structure Cu films were prepared by electrochemical deposition with the Hydrogen bubble dynamic template. The morphologies of the deposited films characterized by Scanning Electronic Microscopy (SEM) exhibit a porous micro-nano hierarchical structure, which consists of three levels in different size scales, namely the honeycomb-like microstructure, the dendritic substructure and the nano particles. Besides, the factors which influenced the microscopic morphology were studied, including the deposition time and the additive Ethylene diamine. By measuring the water contact angle, the porous copper films were found to be super-hydrophobic. The maximum of the contact angles could reach as high as 162.1°. An empirical correlation between morphologies and wetting properties was revealed for the first time. The pore diameter increased simultaneously with the deposition time while the contact angle decreased. The mechanism was illustrated by two classical models. Such super-hydrophobic three-dimensional hierarchical micro-nano structure is expected to have practical application in industry.

  1. Preparation of the Lentinus edodes-based porous biomass carbon by hydrothermal method for capacitive desalination

    Science.gov (United States)

    Yan, Junbin; Zhang, Hexuan; Xie, Zhengzheng; Liu, Jianyun

    2017-08-01

    Biomass carbon materials were prepared by hydrothermal method using Lentinus edodes, followed by activation by ZnCl2 at high carbonization temperature. SEM and contact angle test show that ZnCl2 has a significant effect on the surface morphology and properties of porous carbon materials. Using the porous carbon as electrodes of the capacitor, the specific capacitance of the porous carbon material was found to be 247.6 F/g. The desalination amount of porous carbon material in capacitor cell was 12.9 mg/g, being the 1.9 times of that of the commercial activated carbon.

  2. Supported porous carbon and carbon-CNT nanocomposites for supercapacitor applications

    Science.gov (United States)

    Schopf, Dimitri; Es-Souni, Mohammed

    2016-03-01

    Supported porous carbon and porous carbon-MWCNT-nanocomposite films are produced by pyrolysis of porous polyvinylidene fluoride (PVDF) or porous PVDF-MWCNT-nanocomposite films on thermally resistant substrates. All films are characterized by SEM, RAMAN and XRD. The application of these films as supercapacitors is explored with outstanding supercapacitance values ranging from 80 to 120 F g-1 (up to 70 mF cm-2) in a three-electrode set-up in 1 M KOH, depending on microstructure. Additionally, the implementation of porous nanocarbon-MWCNT-nanocomposite films as electrodes in a symmetrical supercapacitor device is investigated. In all cases, long-term charge-discharge stability is demonstrated.

  3. Characterization of Ge Nano structures Embedded Inside Porous Silicon for Photonics Application

    International Nuclear Information System (INIS)

    Rahim, A.F.A.; Hashim, M.R.; Rahim, A.F.A.; Ali, N.K.

    2011-01-01

    In this work we prepared germanium nano structures by means of filling the material inside porous silicon (PS) using conventional and cost effective technique, thermal evaporator. The PS acts as patterned substrate. It was prepared by anodization of silicon wafer in ethanoic hydrofluoric acid (HF). A Ge layer was then deposited onto the PS by thermal evaporation. This was followed by deposition of Si layer by thermal evaporation and anneal at 650 degree Celsius for 30 min. The process was completed by Ni metal deposition using thermal evaporator followed by metal annealing of 400 degree Celsius for 10 min to form metal semiconductor metal (MSM) photodetector. Structural analysis of the samples was performed using energy dispersive x-ray analysis (EDX), scanning electron microscope (SEM), X-ray diffraction (XRD) and Raman spectroscopy (RS). EDX spectrum suggests the presence of Ge inside the pores structure. Raman spectrum showed that good crystalline structure of Ge can be produced inside silicon pores with a phase with the diamond structure by (111), (220) and (400) reflections. Finally current-voltage (I-V) measurement of the MSM photodetector was carried out and showed lower dark currents compared to that of Si control device. Interestingly the device showed enhanced current gain compared to Si device which can be associated with the presence of Ge nano structures in the porous silicon. (author)

  4. IL 14: Radiolysis of water confined in nano-porous materials

    International Nuclear Information System (INIS)

    Renault, J.P.; Pommeret, S.; Musat, R.; Le Caer, S.; Alam, M.; Mialocq, J.C.

    2010-01-01

    Radiolysis of water in nano-porous media has raised a lot of interest and involved research in the recent years, with respect to concerns arising from the storage of nuclear waste. In the civil nuclear industry, storing for a long time nuclear wastes requires safety evaluations in order to test the durability of the materials involved. Among these materials, concrete and clays are a complex heterogeneous material that traps important quantities of interstitial water. Irradiation that arises from the nuclear wastes stored in these materials may lead to the radiolysis of the interstitial water, and the formation of radiolytic products, such as H 2 , O 2 or H 2 O 2 that may cause the breaking or the corrosion of the confining matrix. This communication will describe the possible impacts of confinement on the radiolysis of water. We will especially discuss the current knowledge about the evolution of radiolytic yields of primary species (hydroxyl radical, dihydrogen, aqueous electron) as a function of the degree of confinement and of the nature of the confining material. SEM picture of a nano-porous gold sample used to study the radiolysis of confined water The yield enhancement observed in many cases revealed original energy and charge transfer phenomena that we tried to decipher. (authors)

  5. Photocatalytic Oxidation of Trichloroethylene in Water Using a Porous Ball of Nano-ZnO and Nanoclay Composite

    Directory of Open Access Journals (Sweden)

    Sol-A Bak

    2015-01-01

    Full Text Available The presence of nondegradable organic compounds and xenobiotic chemicals in water is a great concern for the general public because of their polar properties and toxicity. For instance, trichloroethylene (TCE is a widely used solvent in the chemical industry, and it is also a contaminant of soil, surface water, and groundwater. Recent studies on new treatment technologies have shown that photocatalyst-based advanced oxidation processes are appropriate for removing these polar and toxic compounds from water. The objective of this study was to remove TCE from water using novel nano-ZnO-laponite porous balls prepared from photocatalyst ZnO with nanoscale laponite. These nano-ZnO-laponite porous balls have a porosity of approximately 20%. A lower initial concentration of TCE resulted in high removal efficiency. Moreover, the removal efficiency increased with increasing pH in the photocatalytic degradation experiments employing UVC light with nano-ZnO-laponite. The optimal dosage of nano-ZnO-laponite was 30 g and the use of UVC light resulted in a higher removal efficiency than that achieved with UVA light. In addition, the removal efficiency of TCE significantly increased with increasing light intensity. We think that TCE’s removal in water by using porous ball of nano-ZnO and nanoclay composite is a result of degradation from hydroxide by photons of nano-ZnO and physical absorption in nanoclay.

  6. Porous structured niobium pentoxide/carbon complex for lithium-ion intercalation pseudocapacitors

    International Nuclear Information System (INIS)

    Luo, Guoming; Li, Heshun; Gao, Lixin; Zhang, Daquan; Lin, Tong

    2016-01-01

    Highlights: • A simple one-pot in situ hydrothermal method to prepare T-Nb_2O_5/C. • The composite has well-dispersed C among nano-scale Nb_2O_5. • The composite has excellent large-current discharge property. • The composite has no obvious drop after 1000 cycles at 5 A g"−"1. - Abstract: A facile soft-templated synthesis of the niobium pentoxide/carbon (Nb_2O_5/C) from the polymerization of resorcinol with formaldehyde under the hydrothermal condition is introduced. This material has been characterized by X-ray diffraction (XRD), transmission electron microscope (TEM) and energy dispersive spectrometer (EDS) techniques. The carbon is well-dispersed in the nanostructure along with Nb_2O_5 and the material is porous. The intimate contact between Nb_2O_5 and carbon improves its conductivity. The electrochemical studies revealed that the porous Nb_2O_5/C displayed good pseudocapacitive response. The specific capacitance of the Nb_2O_5/C was 387 F g"−"1 at 0.1 A g"−"1 and 210 F g"−"1 at 5 A g"−"1. The Nb_2O_5/C exhibits superior cycling performance, which can remain about 96% of its initial capacitance after 1000 cycles at 5 A g"−"1.

  7. Recent Advances in Porous Carbon Materials for Electrochemical Energy Storage.

    Science.gov (United States)

    Wang, Libin; Hu, Xianluo

    2018-06-18

    Climate change and the energy crisis have promoted the rapid development of electrochemical energy-storage devices. Owing to many intriguing physicochemical properties, such as excellent chemical stability, high electronic conductivity, and a large specific surface area, porous carbon materials have always been considering as a promising candidate for electrochemical energy storage. To date, a wide variety of porous carbon materials based upon molecular design, pore control, and compositional tailoring have been proposed for energy-storage applications. This focus review summarizes recent advances in the synthesis of various porous carbon materials from the view of energy storage, particularly in the past three years. Their applications in representative electrochemical energy-storage devices, such as lithium-ion batteries, supercapacitors, and lithium-ion hybrid capacitors, are discussed in this review, with a look forward to offer some inspiration and guidelines for the exploitation of advanced carbon-based energy-storage materials. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Carbon Nano tube Composites for Electronic Packaging Applications: A Review

    International Nuclear Information System (INIS)

    Aryasomayajula, L.; Wolter, K.J.

    2013-01-01

    Composite engineering comprises of metal matrix composites. They have high strength-weight ratio, better stiffness, economical production, and ease of availability of raw materials. The discovery of carbon nano tubes has opened new possibilities to face challenges better. Carbon Nano tubes are known for their high mechanical strength, excellent thermal and electrical properties. Recent research has made progress in fabricating carbon nano tube metal matrix and polymer-based composites. The methods of fabrication of these composites, their properties and possible applications restricted to the field of electronic packaging have been discussed in this paper. Experimental and theoretical calculations have shown improved mechanical and physical properties like tensile stress, toughness, and improved electrical and thermal properties. They have also demonstrated the ease of production of the composites and their adaptability as one can tailor their properties as per the requirement. This paper reviews work reported on fabricating and characterizing carbon- nano tube-based metal matrix and polymer composites. The focus of this paper is mainly to review the importance of these composites in the field of electronics packaging.

  9. Conjugate heat transfer in a porous cavity filled with nano-fluids and heated by a triangular thick wall

    International Nuclear Information System (INIS)

    Chamkha, Ali J.; Ismael, Muneer A.

    2013-01-01

    The conjugate natural convection-conduction heat transfer in a square domain composed of nano-fluids filled porous cavity heated by a triangular solid wall is studied under steady-state conditions. The vertical and horizontal walls of the triangular solid wall are kept isothermal and at the same hot temperature Th. The other boundaries surrounding the porous cavity are kept adiabatic except the right vertical wall where it is kept isothermally at the lower temperature T c . Equations governing the heat transfer in the triangular wall and heat and nano-fluid flow, based on the Darcy model, in the nano-fluid-saturated porous medium together with the derived relation of the interface temperature are solved numerically using the over-successive relaxation finite-difference method. A temperature independent nano-fluids properties model is adopted. Three nano-particle types dispersed in one base fluid (water) are investigated. The investigated parameters are the nano-particles volume fraction φ (0-0.2), Rayleigh number Ra (10-1000), solid wall to base-fluid saturated porous medium thermal conductivity ratio K ro (0.44, 1, 23.8), and the triangular wall thickness D (0.1-1). The results are presented in the conventional form; contours of streamlines and isotherms and the local and average Nusselt numbers. At a very low Rayleigh number Ra = 10, a significant enhancement in heat transfer within the porous cavity with φ is observed. Otherwise, the heat transfer may be enhanced or deteriorated with φ depending on the wall thickness D and the Rayleigh number Ra. At high Rayleigh numbers and low conductivity ratios, critical values of D, regardless of 4, are observed and accounted. (authors)

  10. Effects of pH on nano-bubble stability and transport in saturated porous media

    Science.gov (United States)

    Hamamoto, Shoichiro; Takemura, Takato; Suzuki, Kenichiro; Nishimura, Taku

    2018-01-01

    An understanding of nano-scale bubble (NB) transport in porous media is important for potential application of NBs in soil/groundwater remediation. It is expected that the solution chemistry of NB water highly influences the surface characteristics of NBs and porous media and the interaction between them, thus affecting the stability and transport characteristics of NB. In this study, in addition to stability experiments, one-dimensional column transport experiments using glass beads were conducted to investigate the effects of pH on the NB transport behavior. The results showed that the NBs were more stable under higher pH. Column transport experiments revealed that entrapment of NBs, especially larger ones, was enhanced in lower-pH water, likely suggesting pH-dependent NB attachment and physical straining, both of which are also probably influenced by bubble size. Although relatively smaller NBs were released after switching the eluting fluid to one with lower ionic strength, most of the NBs in lower-pH water were still retained in the porous media even altering the chemical condition.

  11. Degradation and biocompatibility of porous nano-hydroxyapatite/polyurethane composite scaffold for bone tissue engineering

    Energy Technology Data Exchange (ETDEWEB)

    Dong Zhihong [Research Center for Nano-Biomaterials, Analytical and Testing Center, Sichuan University, Chengdu 610064 (China); Shanghai Institute of Ceramics, Chinese Academy of Sciences, 1295 Dingxi Road, Shanghai 200050 (China); Li Yubao, E-mail: nic7504@scu.edu.cn [Research Center for Nano-Biomaterials, Analytical and Testing Center, Sichuan University, Chengdu 610064 (China); Zou Qin [Research Center for Nano-Biomaterials, Analytical and Testing Center, Sichuan University, Chengdu 610064 (China)

    2009-04-01

    Porous scaffold containing 30 wt% nano-hydroxyapatite (n-HA) and 70 wt% polyurethane (PU) from castor oil was prepared by a foaming method and investigated by X-ray diffraction (XRD), Fourier transform infrared absorption (FTIR), scanning electron microscopy (SEM) techniques. The results show that n-HA particles disperse homogeneously in the PU matrix. The porous scaffold has not only macropores of 100-800 {mu}m in size but also a lot of micropores on the walls of macropores. The porosity and compressive strength of scaffold are 80% and 271 kPa, respectively. After soaking in simulated body fluid (SBF), hydrolysis and deposition partly occur on the scaffold. The biological evaluation in vitro and in vivo shows that the n-HA/PU scaffold is non-cytotoxic and degradable. The porous structure provides a good microenvironment for cell adherence, growth and proliferation. The n-HA/PU composite scaffold can be satisfied with the basic requirement for tissue engineering, and has the potential to be applied in repair and substitute of human menisci of the knee-joint and articular cartilage.

  12. Enhanced superconducting properties of MgB2 by carbon substitution using carbon containing nano additives

    International Nuclear Information System (INIS)

    Devadas, K.M.; Varghese, Neson; Vinod, K.; Rahul, S.; Thomas, Syju; Anooja, J.B.; Syamaprasad, U.; Sundaresan, A.; Roy, S.B.

    2010-01-01

    A comparative study on the effect of doping of nano carbon, nano diamond and nano SiC in MgB 2 is carried out. The J c (H) is significantly enhanced for all doped samples compared to the pure sample among which MgB 1.9 C 0.1 (nano C) exhibits the best J c (H) performance. The enhanced performance is due to the effective substitution of C at B site which is confirmed by the systematic decrease in both α axis and T c . (author)

  13. Synthesis and structural characterization of coaxial nano tubes intercalated of molybdenum disulfide with carbon; Sintesis y caracterizacion estructural de nanotubos coaxiales intercalados de disulfuro de molibdeno con carbono

    Energy Technology Data Exchange (ETDEWEB)

    Reza San German, C M

    2005-07-01

    In this work the study of some fundamental aspects in the growth of unidimensional systems of coaxial nano tubes from the mold method is approached. This method is an inclusion technique of a precursor reagent into oxide nano porous alumina film (mold), and later applying some processes of synthesis it is gotten to obtain the wished material. The synthesized structures are identified later because they take place by means of the initial formation of nano tubes of MoS{sub 2}, enclosing to carbon nano tubes by the same method, with propylene flow which generates a graphitization process that 'copy' the mold through as it flows. Binary phase MoS{sub 2} + C nano tubes were synthesized by propylene pyrolysis inside MoS{sub 2} nano tubes prepared by template assisted technique. The large coaxial nano tubes constituted of graphite sheets inserted between the MoS{sub 2} layers forming the outer part, and coaxial multi wall carbon nano tubes (MWCNT) intercalated with MoS{sub 2} inside. High resolution electron microscopy (HRTEM), electron energy loss spectroscopy (EELS), high angle annular dark field (HAADF), gatan image filter (GIF), nano beam electron diffraction patterns (NBEDP), along with molecular dynamics simulation and quantum mechanical calculations were used to characterize the samples. The one-dimensional structures exhibit diverse morphologies such as long straight and twisted nano tubes with several structural irregularities. The inter-planar spacing between MoS{sub 2} layers was found to increase from 6.3 to 7.4 A due to intercalation with carbon. Simulated HREM images revealed the presence of these twisted nano structures, with mechanical stretch into intercalate carbon between MoS{sub 2} layers. Our results open up the possibility of using MoS{sub 2} nano tubes as templates for the synthesis of new one- dimensional binary phase systems. (Author)

  14. Synthesis and structural characterization of coaxial nano tubes intercalated of molybdenum disulfide with carbon; Sintesis y caracterizacion estructural de nanotubos coaxiales intercalados de disulfuro de molibdeno con carbono

    Energy Technology Data Exchange (ETDEWEB)

    Reza San German, C.M

    2005-07-01

    In this work the study of some fundamental aspects in the growth of unidimensional systems of coaxial nano tubes from the mold method is approached. This method is an inclusion technique of a precursor reagent into oxide nano porous alumina film (mold), and later applying some processes of synthesis it is gotten to obtain the wished material. The synthesized structures are identified later because they take place by means of the initial formation of nano tubes of MoS{sub 2}, enclosing to carbon nano tubes by the same method, with propylene flow which generates a graphitization process that 'copy' the mold through as it flows. Binary phase MoS{sub 2} + C nano tubes were synthesized by propylene pyrolysis inside MoS{sub 2} nano tubes prepared by template assisted technique. The large coaxial nano tubes constituted of graphite sheets inserted between the MoS{sub 2} layers forming the outer part, and coaxial multi wall carbon nano tubes (MWCNT) intercalated with MoS{sub 2} inside. High resolution electron microscopy (HRTEM), electron energy loss spectroscopy (EELS), high angle annular dark field (HAADF), gatan image filter (GIF), nano beam electron diffraction patterns (NBEDP), along with molecular dynamics simulation and quantum mechanical calculations were used to characterize the samples. The one-dimensional structures exhibit diverse morphologies such as long straight and twisted nano tubes with several structural irregularities. The inter-planar spacing between MoS{sub 2} layers was found to increase from 6.3 to 7.4 A due to intercalation with carbon. Simulated HREM images revealed the presence of these twisted nano structures, with mechanical stretch into intercalate carbon between MoS{sub 2} layers. Our results open up the possibility of using MoS{sub 2} nano tubes as templates for the synthesis of new one- dimensional binary phase systems. (Author)

  15. Synthesis of MnO nano-particle@Flourine doped carbon and its application in hybrid supercapacitor

    Energy Technology Data Exchange (ETDEWEB)

    Qu, Deyu; Feng, Xiaoke [Department of Chemistry, School of Chemistry, Chemical Engineering and Life Science, Wuhan University of Technology, Wuhan 430070, Hubei (China); Wei, Xi [School of Materials Science and Engineering, State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070, Hubei (China); Guo, Liping [Department of Chemistry, School of Chemistry, Chemical Engineering and Life Science, Wuhan University of Technology, Wuhan 430070, Hubei (China); Cai, Haopeng, E-mail: cai_haopeng@whut.edu.cn [School of Materials Science and Engineering, State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070, Hubei (China); Tang, Haolin [School of Materials Science and Engineering, State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070, Hubei (China); Xie, Zhizhong, E-mail: zhizhong_xie@163.com [Department of Chemistry, School of Chemistry, Chemical Engineering and Life Science, Wuhan University of Technology, Wuhan 430070, Hubei (China)

    2017-08-15

    Highlights: • A Fluorine doped carbon encapsulated MnO nanoparticle material was fabricated through a self-assembly method. • Nafion ionomers was used as the fluorine and carbon precursor. • A lithium ion supercapacitor was assemblied by using MnO@FC and porous carbon. • A stable energy density as well as superior cycling stability were demonstrated in this hybrid system. - Abstract: A flourine doped carbon materials encapsulated MnO nano-particle was synthesized through a self-assembly method. The MnO nano-crystal covered with a thin layer of graphite were achieved. This hybrid MnO/carbon materials were employed as negative electrode in a new lithium ion hybrid supercapacitor, while the electrochemical double-layer porous carbon served as positive electrode. The electrochemical performances of this hybrid device were investigated and exhibited relative high capacity upto 40 mAh g{sup −1} in an applied current of 200 mAh g{sup −1}, good rate performance as well as superior cycling stability.

  16. Reactive Melt Infiltration Of Silicon Into Porous Carbon

    Science.gov (United States)

    Behrendt, Donald R.; Singh, Mrityunjay

    1994-01-01

    Report describes study of synthesis of silicon carbide and related ceramics by reactive melt infiltration of silicon and silicon/molybdenum alloys into porous carbon preforms. Reactive melt infiltration has potential for making components in nearly net shape, performed in less time and at lower temperature. Object of study to determine effect of initial pore volume fraction, pore size, and infiltration material on quality of resultant product.

  17. Single-layer nano-carbon film, diamond film, and diamond/nano-carbon composite film field emission performance comparison

    International Nuclear Information System (INIS)

    Wang, Xiaoping; Wang, Jinye; Wang, Lijun

    2016-01-01

    A series of single-layer nano-carbon (SNC) films, diamond films, and diamond/nano-carbon (D/NC) composite films have been prepared on the highly doped silicon substrate by using microwave plasma chemical vapor deposition techniques. The films were characterised by scanning electron microscopy, Raman spectroscopy, and field emission I-V measurements. The experimental results indicated that the field emission maximum current density of D/NC composite films is 11.8–17.8 times that of diamond films. And the field emission current density of D/NC composite films is 2.9–5 times that of SNC films at an electric field of 3.0 V/μm. At the same time, the D/NC composite film exhibits the advantage of improved reproducibility and long term stability (both of the nano-carbon film within the D/NC composite cathode and the SNC cathode were prepared under the same experimental conditions). And for the D/NC composite sample, a high current density of 10 mA/cm"2 at an electric field of 3.0 V/μm was obtained. Diamond layer can effectively improve the field emission characteristics of nano-carbon film. The reason may be due to the diamond film acts as the electron acceleration layer.

  18. Preparation of ultrasmall porous carbon nanospheres by reverse microemulsion-hydrothermal method

    Science.gov (United States)

    Wang, Jiasheng; Zhao, Yahong; Wang, Wan-Hui; Bao, Ming

    Porous carbon nanospheres (CNSs) have wide applications. A big challenge in materials science is synthesis of discrete ultrasmall porous carbon nanospheres. Herein, we report a facile reverse microemulsion-hydrothermal method to prepare discrete porous CNSs. The obtained CNSs possess an average diameter of 20nm and pores of 0.7nm and 3.4nm. Our work has provided a convenient method for the controllable synthesis of ultrasmall porous CNSs with potential applications.

  19. Spatially confined synthesis of SiOx nano-rod with size-controlled Si quantum dots in nano-porous anodic aluminum oxide membrane.

    Science.gov (United States)

    Pai, Yi-Hao; Lin, Gong-Ru

    2011-01-17

    By depositing Si-rich SiOx nano-rod in nano-porous anodic aluminum oxide (AAO) membrane using PECVD, the spatially confined synthesis of Si quantum-dots (Si-QDs) with ultra-bright photoluminescence spectra are demonstrated after low-temperature annealing. Spatially confined SiOx nano-rod in nano-porous AAO membrane greatly increases the density of nucleated positions for Si-QD precursors, which essentially impedes the route of thermally diffused Si atoms and confines the degree of atomic self-aggregation. The diffusion controlled growth mechanism is employed to determine the activation energy of 6.284 kJ mole(-1) and diffusion length of 2.84 nm for SiO1.5 nano-rod in nano-porous AAO membrane. HRTEM results verify that the reduced geometric dimension of the SiOx host matrix effectively constrain the buried Si-QD size at even lower annealing temperature. The spatially confined synthesis of Si-QD essentially contributes the intense PL with its spectral linewidth shrinking from 210 to 140 nm and its peak intensity enhancing by two orders of magnitude, corresponding to the reduction on both the average Si-QD size and its standard deviation from 2.6 to 2.0 nm and from 25% to 12.5%, respectively. The red-shifted PL wavelength of the Si-QD reveals an inverse exponential trend with increasing temperature of annealing, which is in good agree with the Si-QD size simulation via the atomic diffusion theory.

  20. Effects of Carbonization Parameters of Moso-Bamboo-Based Porous Charcoal on Capturing Carbon Dioxide

    Directory of Open Access Journals (Sweden)

    Pei-Hsing Huang

    2014-01-01

    Full Text Available This study experimentally analyzed the carbon dioxide adsorption capacity of Moso-bamboo- (Phyllostachys edulis- based porous charcoal. The porous charcoal was prepared at various carbonization temperatures and ground into powders with 60, 100, and 170 meshes, respectively. In order to understand the adsorption characteristics of porous charcoal, its fundamental properties, namely, charcoal yield, ash content, pH value, Brunauer-Emmett-Teller (BET surface area, iodine number, pore volume, and powder size, were analyzed. The results show that when the carbonization temperature was increased, the charcoal yield decreased and the pH value increased. Moreover, the bamboo carbonized at a temperature of 1000°C for 2 h had the highest iodine sorption value and BET surface area. In the experiments, charcoal powders prepared at various carbonization temperatures were used to adsorb 1.854% CO2 for 120 h. The results show that the bamboo charcoal carbonized at 1000°C and ground with a 170 mesh had the best adsorption capacity, significantly decreasing the CO2 concentration to 0.836%. At room temperature and atmospheric pressure, the Moso-bamboo-based porous charcoal exhibited much better CO2 adsorption capacity compared to that of commercially available 350-mesh activated carbon.

  1. Tunable Degradation Rate and Favorable Bioactivity of Porous Calcium Sulfate Scaffolds by Introducing Nano-Hydroxyapatite

    Directory of Open Access Journals (Sweden)

    Jianhua Zhou

    2016-12-01

    Full Text Available The bone scaffolds should possess suitable physicochemical properties and osteogenic activities. In this study, porous calcium sulfate (CaSO4 scaffolds were fabricated successfully via selected laser sintering (SLS. Nano-hydroxyapatite (nHAp, a bioactive material with a low degradation rate, was introduced into CaSO4 scaffolds to overcome the overquick absorption. The results demonstrated that nHAp could not only control the degradation rate of scaffolds by adjusting their content, but also improve the pH environment by alleviating the acidification progress during the degradation of CaSO4 scaffolds. Moreover, the improved scaffolds were covered completely with the apatite spherulites in simulated body fluid (SBF, showing their favorable bioactivity. In addition, the compression strength and fracture toughness were distinctly enhanced, which could be ascribed to large specific area of nHAp and the corresponding stress transfer.

  2. Tailoring properties of porous Poly (vinylidene fluoride) scaffold through nano-sized 58s bioactive glass.

    Science.gov (United States)

    Shuai, Cijun; Huang, Wei; Feng, Pei; Gao, Chengde; Shuai, Xiong; Xiao, Tao; Deng, Youwen; Peng, Shuping; Wu, Ping

    2016-01-01

    The biological properties of porous poly (vinylidene fluoride) (PVDF) scaffolds fabricated by selective laser sintering were tailored through nano-sized 58s bioactive glass. The results showed that 58s bioactive glass distributed evenly in the PVDF matrix. There were some exposed particles on the surface which provided attachment sites for biological response. It was confirmed that the scaffolds had highly bioactivity by the formation of bone-like apatite in simulated body fluid. And the bone-like apatite became dense with the increase in 58s bioactive glass and culture time. Moreover, the scaffolds were suitable for cell adhesion and proliferation compared with the PVDF scaffolds without 58s bioactive glass. The research showed that the PVDF/58s bioactive glass scaffolds had latent application in bone tissue engineering.

  3. Carbon Nano-Tube (CNT) Reinforced COPV

    Data.gov (United States)

    National Aeronautics and Space Administration — Reduce the structural mass of future aerospace vehicles through the development of ultra lightweight materials and structures through the use of: Carbon nanotube...

  4. Method of producing carbon coated nano- and micron-scale particles

    Science.gov (United States)

    Perry, W. Lee; Weigle, John C; Phillips, Jonathan

    2013-12-17

    A method of making carbon-coated nano- or micron-scale particles comprising entraining particles in an aerosol gas, providing a carbon-containing gas, providing a plasma gas, mixing the aerosol gas, the carbon-containing gas, and the plasma gas proximate a torch, bombarding the mixed gases with microwaves, and collecting resulting carbon-coated nano- or micron-scale particles.

  5. Porous Ni3(NO3)2(OH)4 nano-sheets for supercapacitors: Facile synthesis and excellent rate performance at high mass loadings

    Science.gov (United States)

    Shi, Mingjie; Cui, Mangwei; Kang, Litao; Li, Taotao; Yun, Shan; Du, Jing; Xu, Shoudong; Liu, Ying

    2018-01-01

    For supercapacitors, pores in electrode materials can accelerate chemical reaction kinetics by shortening ion diffusion distances and by enlarging electrolyte/electrode interfaces. This article describes a simple one-step route for the preparation of pure-phase porous Ni3(NO3)2(OH)4 nano-sheets by directly heating a mild Ni(NO3)2 and urea solution. During heating, urea decomposed into NH3·H2O, which provided a suitable alkaline environment for the formation of Ni3(NO3)2(OH)4 nano-sheets. Meanwhile, the side product, NH4NO3, created numerous pores as a pore-forming agent. After NH4NO3 removal, the specific surface areas and pore volumes of products were boosted by ∼180-times (from 0.61 to 113.12 m2/g) and ∼90-times (from 3.40 × 10-3 to 3.17 × 10-1 m2/g), respectively. As a cathode material of supercapacitor, the porous Ni3(NO3)2(OH)4 nano-sheets exhibited a high specific capacitance of 1094 F/g at an ultrahigh mass loading of 17.55 mg/cm2, leading to an impressive areal capacitance of 19.2 F/cm2. Furthermore, a Ni3(NO3)2(OH)4 nano-sheet//commercial active carbon asymmetric supercapacitor was constructed and delivered an energy density of 33.2 Wh/Kg at a power density of 190.5 W/Kg, based on the mass of active materials on both electrodes.

  6. The Time-Dependency of Deformation in Porous Carbonate Rocks

    Science.gov (United States)

    Kibikas, W. M.; Lisabeth, H. P.; Zhu, W.

    2016-12-01

    Porous carbonate rocks are natural reservoirs for freshwater and hydrocarbons. More recently, due to their potential for geothermal energy generation as well as carbon sequestration, there are renewed interests in better understanding of the deformation behavior of carbonate rocks. We conducted a series of deformation experiments to investigate the effects of strain rate and pore fluid chemistry on rock strength and transport properties of porous limestones. Indiana limestone samples with initial porosity of 16% are deformed at 25 °C under effective pressures of 10, 30, and 50 MPa. Under nominally dry conditions, the limestone samples are deformed under 3 different strain rates, 1.5 x 10-4 s-1, 1.5 x 10-5 s-1 and 1.5 x 10-6 s-1 respectively. The experimental results indicate that the mechanical behavior is both rate- and pressure-dependent. At low confining pressures, post-yielding deformation changes from predominantly strain softening to strain hardening as strain rate decreases. At high confining pressures, while all samples exhibit shear-enhanced compaction, decreasing strain rate leads to an increase in compaction. Slower strain rates enhance compaction at all confining pressure conditions. The rate-dependence of deformation behaviors of porous carbonate rocks at dry conditions indicates there is a strong visco-elastic coupling for the degradation of elastic modulus with increasing plastic deformation. In fluid saturated samples, inelastic strain of limestone is partitioned among low temperature plasticity, cataclasis and solution transport. Comparison of inelastic behaviors of samples deformed with distilled water and CO2-saturated aqueous solution as pore fluids provide experimental constraints on the relative activities of the various mechanisms. Detailed microstructural analysis is conducted to take into account the links between stress, microstructure and the inelastic behavior and failure mechanisms.

  7. Electrospinning of Nano-Porous Cellulose Acetate Fibers Under Humidified Condition

    Directory of Open Access Journals (Sweden)

    Hamid Fattahi Juybari

    2016-01-01

    Full Text Available Electrospinning as a simple method was used to produce cellulose acetate porous fibers. Motivation for production of fibers with small diameter in the submicron and nano scales was to achieve the material with a large surfacearea with porosity formation in the structure of electrospun fibers. In this study, porous cellulose acetate (CA fibers were produced by electrospinning process from solution of CA/acetone/water. The porosity of the fiber was controlled by adjustment of the temperature and humidity of electrospinning chamber. Scanning electron microscopy (SEM and densitometry were employed to evaluate the morphology and porosity of the samples. The results showed that the morphology and porosity of cellulose acetate fibers depend on the polymer solution concentration and relative humidity of electrospinning atmosphere. Cellulose acetate fibers were electrospun best at the concentrations of 12 to 18 wt% and relative humidity range of 40 to 80%. The highest porosity was obtained at the relative humidity of 80% and concentration of 15 wt%. In addition, by increasing the relative humidity of electrospinning environment and polymer concentration, the average diameter of the fibers was increased. With increasing the polymer concentration, there was less likelihood in thermodynamic instability and phase separation. In contrast, increases in relative humidity led to diffusion of more water into the electrospinning jet, giving rise to phase separation. Our observations revealed that the skin of fibers was formed at the earlier stage of the process and prevented the stretch in electrospinning jet.

  8. Carbon Nano tubes Based Mixed Matrix Membrane for Gas Separation

    International Nuclear Information System (INIS)

    Sanip, S.M.; Ismail, A.F.; Goh, P.S.; Norrdin, M.N.A.; Soga, T.; Tanemura, M.; Yasuhiko, H.

    2011-01-01

    Carbon nano tubes based mixed matrix membrane (MMM) was prepared by the solution casting method in which the functionalized multi walled carbon nano tubes (f-MWNTs) were embedded into the polyimide membrane and the resulting membranes were characterized. The effect of nominal MWNTs content between 0.5 and 1.0 wt % on the gas separation properties were looked into. The morphologies of the MMM also indicated that at 0.7 % loading of f- MWNTs, the structures of the MMM showed uniform finger-like structures which have facilitated the fast gas transport through the polymer matrix. It may also be concluded that addition of open ended and shortened MWNTs to the polymer matrix can improve its permeability by increasing diffusivity through the MWNTs smooth cavity. (author)

  9. Time-Domain Analysis of Coupled Carbon Nano tube Interconnects

    International Nuclear Information System (INIS)

    Fathi, D.

    2014-01-01

    This paper describes a new method for the analysis of coupling effects including the crosstalk effects between two driven coupled single-walled carbon nano tubes (SWCNTs) and the intertalk effects between two neighboring shells in a multi walled carbon nano tube (MWCNT), based on transmission line circuit modeling. Using rigorous calculations, a new parametric transfer function has been obtained for the analysis of the impact of aggressor line on the victim line, which depends on the various coupling parameters such as the mutual inductance, the coupling capacitance, and the tunneling resistance. The influences of various parameters such as the contact resistance and the switching factor on the time behavior of coupling effects between the two coupled CNTs and an important effect named “crosstalk-induced delay” are studied and analyzed

  10. Modification of cement concrete by multilayer carbon nano-tubes

    International Nuclear Information System (INIS)

    Yakovlev, G.I.; Pervushin, G.N.; Pudov, I.A.; Korzhenko, A.

    2012-01-01

    The compact structure of protective concrete-conservative on the basis of Portland cement modified by carbon nano-dispersed systems has been studied. Multilayer carbon nano-tubes Graphistrength TM by 'Arkema' dispersed in hydrodynamic plant in the solution of surfactant Polyplast SP-1 have been used as modifying additives. The bending strength of fine grain concrete has been observed to increase by 45.1% and compression strength - by 96.8%. The concrete strength increase is related to morphological changes of crystalline hydrate new formations providing the formation of less defective structure of cement matrix of high density, preventing the migration of radionuclides into the environment in the process of radioactive waste conservation

  11. Converting Corncob to Activated Porous Carbon for Supercapacitor Application

    Directory of Open Access Journals (Sweden)

    Shaoran Yang

    2018-03-01

    Full Text Available Carbon materials derived from biomass are promising electrode materials for supercapacitor application due to their specific porosity, low cost and electrochemical stability. Herein, a hierarchical porous carbon derived from corncob was developed for use as electrodes. Benefitting from its hierarchical porosity, inherited from the natural structure of corncob, high BET surface area (1471.4 m2·g−1 and excellent electrical conductivity, the novel carbon material exhibited a specific capacitance of 293 F·g−1 at 1 A·g−1 in 6 M KOH electrolyte and maintained at 195 F·g−1 at 5 A·g−1. In addition, a two-electrode device was assembled and delivered an energy density of 20.15 Wh·kg−1 at a power density of 500 W·kg−1 and an outstanding stability of 99.9% capacitance retention after 4000 cycles.

  12. VOPcPhO:P3HT composite micro-structures with nano-porous surface morphology

    Energy Technology Data Exchange (ETDEWEB)

    Azmer, Mohamad Izzat [Low Dimensional Materials Research Centre (LDMRC), Department of Physics, Faculty of Science, University of Malaya, 50603 Kuala Lumpur (Malaysia); Ahmad, Zubair, E-mail: zubairtarar@qu.edu.qa [Center for Advanced Materials (CAM), Qatar University, P. O. Box 2713, Doha (Qatar); Sulaiman, Khaulah, E-mail: khaulah@um.edu.my [Low Dimensional Materials Research Centre (LDMRC), Department of Physics, Faculty of Science, University of Malaya, 50603 Kuala Lumpur (Malaysia); Touati, Farid [Department of Electrical Engineering, College of Engineering, Qatar University, P. O. Box 2713, Doha (Qatar); Bawazeer, Tahani M. [Department of Chemistry, Faculty of Applied Science, Umm Al-Qura University, Makkah (Saudi Arabia); Alsoufi, Mohammad S. [Mechanical Engineering Department, College of Engineering and Islamic Architecture, Umm Al-Qura University, Makkah (Saudi Arabia)

    2017-03-31

    Highlights: • VOPcPhO:P3HT micro-structures with nano-porous surface morphology have been formed. • Multidimensional structures have been formed by electro-spraying technique. • The electro-sprayed films are very promising for the humidity sensors. - Abstract: In this paper, composite micro-structures of Vanadyl 2,9,16,23-tetraphenoxy-29H,31H-phthalocyanine) (VOPcPhO) and Poly (3-hexylthiophene-2,5-diyl) (P3HT) complex with nano-porous surface morphology have been developed by electro-spraying technique. The structural and morphological characteristics of the VOPcPhO:P3HT composite films have been studied by field emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM). The multidimensional VOPcPhO:P3HT micro-structures formed by electro-spraying with nano-porous surface morphology are very promising for the humidity sensors due to the pore sizes in the range of micro to nano-meters scale. The performance of the VOPcPhO:P3HT electro-sprayed sensor is superior in term of sensitivity, hysteresis and response/recovery times as compared to the spin-coated one. The electro-sprayed humidity sensor exhibits ∼3 times and 0.19 times lower hysteresis in capacitive and resistive mode, respectively, as compared to the spin-coated humidity sensor.

  13. Injectable porous nano-hydroxyapatite/chitosan/tripolyphosphate scaffolds with improved compressive strength for bone regeneration

    Energy Technology Data Exchange (ETDEWEB)

    Uswatta, Suren P.; Okeke, Israel U. [Department of Bioengineering, The University of Toledo, Toledo, OH 43614 (United States); Jayasuriya, Ambalangodage C., E-mail: a.jayasuriya@utoledo.edu [Department of Bioengineering, The University of Toledo, Toledo, OH 43614 (United States); Department of Orthopaedic Surgery, The University of Toledo, Toledo, OH 43614 (United States)

    2016-12-01

    In this study we have fabricated porous injectable spherical scaffolds using chitosan biopolymer, sodium tripolyphosphate (TPP) and nano-hydroxyapatite (nHA). TPP was primarily used as an ionic crosslinker to crosslink nHA/chitosan droplets. We hypothesized that incorporating nHA into chitosan could support osteoconduction by emulating the mineralized cortical bone structure, and improve the Ultimate Compressive Strength (UCS) of the scaffolds. We prepared chitosan solutions with 0.5%, 1% and 2% (w/v) nHA concentration and used simple coacervation and lyophilization techniques to obtain spherical scaffolds. Lyophilized spherical scaffolds had a mean diameter of 1.33 mm (n = 25). Further, portion from each group lyophilized scaffolds were soaked and dried to obtain Lyophilized Soaked and Dried (LSD) scaffolds. LSD scaffolds had a mean diameter of 0.93 mm (n = 25) which is promising property for the injectability. Scanning Electron Microscopy images showed porous surface morphology and interconnected pore structures inside the scaffolds. Lyophilized and LSD scaffolds had surface pores < 10 and 2 μm, respectively. 2% nHA/chitosan LSD scaffolds exhibited UCS of 8.59 MPa compared to UCS of 2% nHA/chitosan lyophilized scaffolds at 3.93 MPa. Standardize UCS values were 79.98 MPa and 357 MPa for 2% nHA/chitosan lyophilized and LSD particles respectively. One-way ANOVA results showed a significant increase (p < 0.001) in UCS of 1% and 2% nHA/chitosan lyophilized scaffolds compared to 0% and 0.5% nHA/chitosan lyophilized scaffolds. Moreover, 2% nHA LSD scaffolds had significantly increased (p < 0.005) their mean UCS by 120% compared to 2% nHA lyophilized scaffolds. In a drawback, all scaffolds have lost their mechanical properties by 95% on the 2nd day when fully immersed in phosphate buffered saline. Additionally live and dead cell assay showed no cytotoxicity and excellent osteoblast attachment to both lyophilized and LSD scaffolds at the end of 14th day of in vitro

  14. Injectable porous nano-hydroxyapatite/chitosan/tripolyphosphate scaffolds with improved compressive strength for bone regeneration

    International Nuclear Information System (INIS)

    Uswatta, Suren P.; Okeke, Israel U.; Jayasuriya, Ambalangodage C.

    2016-01-01

    In this study we have fabricated porous injectable spherical scaffolds using chitosan biopolymer, sodium tripolyphosphate (TPP) and nano-hydroxyapatite (nHA). TPP was primarily used as an ionic crosslinker to crosslink nHA/chitosan droplets. We hypothesized that incorporating nHA into chitosan could support osteoconduction by emulating the mineralized cortical bone structure, and improve the Ultimate Compressive Strength (UCS) of the scaffolds. We prepared chitosan solutions with 0.5%, 1% and 2% (w/v) nHA concentration and used simple coacervation and lyophilization techniques to obtain spherical scaffolds. Lyophilized spherical scaffolds had a mean diameter of 1.33 mm (n = 25). Further, portion from each group lyophilized scaffolds were soaked and dried to obtain Lyophilized Soaked and Dried (LSD) scaffolds. LSD scaffolds had a mean diameter of 0.93 mm (n = 25) which is promising property for the injectability. Scanning Electron Microscopy images showed porous surface morphology and interconnected pore structures inside the scaffolds. Lyophilized and LSD scaffolds had surface pores < 10 and 2 μm, respectively. 2% nHA/chitosan LSD scaffolds exhibited UCS of 8.59 MPa compared to UCS of 2% nHA/chitosan lyophilized scaffolds at 3.93 MPa. Standardize UCS values were 79.98 MPa and 357 MPa for 2% nHA/chitosan lyophilized and LSD particles respectively. One-way ANOVA results showed a significant increase (p < 0.001) in UCS of 1% and 2% nHA/chitosan lyophilized scaffolds compared to 0% and 0.5% nHA/chitosan lyophilized scaffolds. Moreover, 2% nHA LSD scaffolds had significantly increased (p < 0.005) their mean UCS by 120% compared to 2% nHA lyophilized scaffolds. In a drawback, all scaffolds have lost their mechanical properties by 95% on the 2nd day when fully immersed in phosphate buffered saline. Additionally live and dead cell assay showed no cytotoxicity and excellent osteoblast attachment to both lyophilized and LSD scaffolds at the end of 14th day of in vitro

  15. Study on Carbon Nano composite Counter electrode for Dye-Sensitized Solar Cells

    International Nuclear Information System (INIS)

    Chen, Y.; Zhang, H.; Lin, J.

    2012-01-01

    Carbon nano composite electrodes were prepared by adding carbon nano tubes (CNTs) into carbon black as counter electrodes of dye-sensitized solar cells (DSSCs). The morphology and structure of carbon nano composite electrodes were studied by scanning electron microscopy. The influence of CNTs on the electrochemical performance of carbon nano composite electrodes is investigated by cyclic voltammetry and electrochemical impedance spectroscopy. Carbon nano composite electrodes with CNTs exhibit a highly interconnected network structure with high electrical conductivity and good catalytic activity. The influence of different CNTs content in carbon nano composite electrodes on the open-circuit voltage, short-circuit current, and filling factor of DSSCs is also investigated. DSSCs with 10% CNTs content exhibit the best photovoltaic performance in our experiments.

  16. Carbon nano tubes -Buckypaper- radiation studies for medical physics application

    Energy Technology Data Exchange (ETDEWEB)

    Alanazi, A.; Alkhorayef, M.; Dalton, A.; Bradley, D. A. [University of Surrey, Department of Physics, College for Nuclear and Radiation Physics, Guildford, Surrey GR2 7XH (United Kingdom); Alzimami, K. [King Saud University, Department of Radiological Sciences, P. O. Box 10219, Riyadh 11433 (Saudi Arabia); Abuhadi, N., E-mail: a.alanazi@surrey.ac.uk [Jazan University, Faculty of Medical Applied Sciences, Diagnostic Radiology Department, P. O. Box 114, Jazan (Saudi Arabia)

    2015-10-15

    Radiation dosimetry underpins safe and effective clinical applications of radiation. Many materials have been used to measure the radiation dose deposited in human tissue, their radiation response requiring the application of correction factors to account for various influencing factors, including sensitivity to dose and energy dependence. In regard to the latter, account needs to be taken of difference from the effective atomic number of human tissue, soft or calcified. Graphite ion chambers and semiconductor diode detectors have been used to make measurements in phantoms but these active devices represent a clear disadvantage when considered for in vivo dosimetry. In both circumstances, dosimeters with atomic number similar to human tissue are needed. Carbon nano tubes have properties that potentially meet the demand, requiring low voltage in active devices and an atomic number similar to adipose tissue. In this study, single-wall carbon nano tubes buckypaper has been used to measure the beta particle dose deposited from a strontium-90 source, the medium displaying thermoluminescence at potentially useful sensitivity. As an example, the samples show a clear response for a dose of 2 Gy. This finding suggests that carbon nano tubes can be used as a passive dosimeter specifically for the high levels of radiation exposures used in radiation therapy. Furthermore, the finding points towards further potential applications such as for space radiation measurements, not least because the medium satisfies a demand for light but strong materials of minimal capacitance. (Author)

  17. Carbon nano tubes -Buckypaper- radiation studies for medical physics application

    International Nuclear Information System (INIS)

    Alanazi, A.; Alkhorayef, M.; Dalton, A.; Bradley, D. A.; Alzimami, K.; Abuhadi, N.

    2015-10-01

    Radiation dosimetry underpins safe and effective clinical applications of radiation. Many materials have been used to measure the radiation dose deposited in human tissue, their radiation response requiring the application of correction factors to account for various influencing factors, including sensitivity to dose and energy dependence. In regard to the latter, account needs to be taken of difference from the effective atomic number of human tissue, soft or calcified. Graphite ion chambers and semiconductor diode detectors have been used to make measurements in phantoms but these active devices represent a clear disadvantage when considered for in vivo dosimetry. In both circumstances, dosimeters with atomic number similar to human tissue are needed. Carbon nano tubes have properties that potentially meet the demand, requiring low voltage in active devices and an atomic number similar to adipose tissue. In this study, single-wall carbon nano tubes buckypaper has been used to measure the beta particle dose deposited from a strontium-90 source, the medium displaying thermoluminescence at potentially useful sensitivity. As an example, the samples show a clear response for a dose of 2 Gy. This finding suggests that carbon nano tubes can be used as a passive dosimeter specifically for the high levels of radiation exposures used in radiation therapy. Furthermore, the finding points towards further potential applications such as for space radiation measurements, not least because the medium satisfies a demand for light but strong materials of minimal capacitance. (Author)

  18. Nano-QSAR: Genotoxicity of Multi-Walled Carbon Nanotubes

    International Nuclear Information System (INIS)

    Toropova, A. P.; Toropov, A. A.; Rallo, R.; Leszczynska, D.; Leszczynski, J.

    2016-01-01

    The study was carried out to develop an efficient approach for prediction the genotoxicity of carbon nano tubes. The experimental data on the bacterial reverse mutation test (TA100) on multi-walled carbon nano tubes was collected from the literature and examined as an endpoint. By means of the optimal descriptors calculated with the Monte Carlo method a mathematical model of the endpoint was built up. The model is represented by a function of: (i) dose (μg/plate); (ii) metabolic activation (i.e. with S9 mix or without S9 mix); and (iii) two types of multi-walled carbon nano tubes. The above listed conditions were represented by so-called quasi-SMILES. Simplified molecular input-line entry system (SMILES) is a tool for representation of molecular structure. The quasi-SMILES is a tool to represent physicochemical and / or biochemical conditions for building up a predictive model. Thus, instead of well-known paradigm of predictive modeling “endpoint is a mathematical function of molecular structure” a fresh paradigm “endpoint is a mathematical function of available eclectic data (conditions) is suggested.

  19. Improved electrochemical performance of hierarchical porous carbon/polyaniline composites

    International Nuclear Information System (INIS)

    Hu Juan; Wang Huanlei; Huang Xiao

    2012-01-01

    Highlights: ► Polyaniline-coated hierarchical porous carbon (HPC) composites have been synthesized by in situ polymerization. ► The HPC/polyaniline composite has significantly better electrochemical capacitance performance than pure HPC and polyaniline. ► The amount of polyaniline loading has a significant effect on the composites’ electrochemical performances. - Abstract: Polyaniline (PANI)-coated hierarchical porous carbon (HPC) composites (HPC/PANI) for use as supercapacitor electrodes were prepared by in situ chemical oxidation polymerization at 273 K of an aniline solution containing well-dispersed HPC particles. After polymerization, a thin layer of PANI was coated on the surface of the HPC particles, which was confirmed by Fourier transform infrared spectroscopy (FT-IR), transmission electron microscope (TEM) and scanning electron microscopy (SEM). Compared to pure PANI and HPC, the electrochemical capacitance performance of the composites was significantly improved. The highest specific capacitance of the composites obtained is 478 F g −1 at 1 mV s −1 , which is more than twice as that of pure PANI and three times as that of pure HPC. Because of the influence from the hierarchical pore structure of the carbon material, the calculated specific capacitance of PANI in the composite (pseudocapacitance contribution from PANI) is almost one magnitude higher than that of pure PANI.

  20. Interaction between carboxyl-functionalized carbon black nanoparticles and porous media

    Science.gov (United States)

    Kim, Song-Bae; Kang, Jin-Kyu; Yi, In-Geol

    2015-04-01

    Carbon nanomaterials, such as carbon nanotubes, fullerene, and graphene, have received considerable attention due to their unique physical and chemical characteristics, leading to mass production and widespread application in industrial, commercial, and environmental fields. During their life cycle from production to disposal, however, carbon nanomaterials are inevitably released into water and soil environments, which have resulted in concern about their health and environmental impacts. Carbon black is a nano-sized amorphous carbon powder that typically contains 90-99% elemental carbon. It can be produced from incomplete combustion of hydrocarbons in petroleum and coal. Carbon black is widely used in chemical and industrial products or applications such as ink pigments, coating plastics, the rubber industry, and composite reinforcements. Even though carbon black is strongly hydrophobic and tends to aggregate in water, it can be dispersed in aqueous media through surface functionalization or surfactant use. The aim of this study was therefore to investigate the transport behavior of carboxyl-functionalized carbon black nanoparticles (CBNPs) in porous media. Column experiments were performed for potassium chloride (KCl), a conservative tracer, and CBNPs under saturated flow conditions. Column experiments was conducted in duplicate using quartz sand, iron oxide-coated sand (IOCS), and aluminum oxide-coated sand (AOCS) to examine the effect of metal (Fe, Al) oxide presence on the transport of CBNPs. Breakthrough curves (BTCs) of CBNPs and chloride were obtained by monitoring effluent, and then mass recovery was quantified from these curves. Additionally, interaction energy profiles for CBNP-porous media were calculated using DLVO theory for sphere-plate geometry. The BTCs of chloride had relative peak concentrations ranging from 0.895 to 0.990. Transport parameters (pore-water velocity v, hydrodynamic dispersion coefficient D) obtained by the model fit from the

  1. Biomass derived porous nitrogen doped carbon for electrochemical devices

    Directory of Open Access Journals (Sweden)

    Litao Yan

    2017-04-01

    Full Text Available Biomass derived porous nanostructured nitrogen doped carbon (PNC has been extensively investigated as the electrode material for electrochemical catalytic reactions and rechargeable batteries. Biomass with and without containing nitrogen could be designed and optimized to prepare PNC via hydrothermal carbonization, pyrolysis, and other methods. The presence of nitrogen in carbon can provide more active sites for ion absorption, improve the electronic conductivity, increase the bonding between carbon and sulfur, and enhance the electrochemical catalytic reaction. The synthetic methods of natural biomass derived PNC, heteroatomic co- or tri-doping into biomass derived carbon and the application of biomass derived PNC in rechargeable Li/Na batteries, high energy density Li–S batteries, supercapacitors, metal-air batteries and electrochemical catalytic reaction (oxygen reduction and evolution reactions, hydrogen evolution reaction are summarized and discussed in this review. Biomass derived PNCs deliver high performance electrochemical storage properties for rechargeable batteries/supercapacitors and superior electrochemical catalytic performance toward hydrogen evolution, oxygen reduction and evolution, as promising electrodes for electrochemical devices including battery technologies, fuel cell and electrolyzer. Keywords: Biomass, Nitrogen doped carbon, Batteries, Fuel cell, Electrolyzer

  2. Synthesis of carbon nano structures by plasma discharge

    International Nuclear Information System (INIS)

    Jimenez L, M.L.

    2007-01-01

    Due to the great quantity of applications of carbon neocarcinostatin (NEC) in diverse areas like: synthesis of super-resistant materials, hydrogen storage, nano sensors generation and nano catalysts, one has seen the necessity to generate new synthesis processes of these materials as well as to already improve those existent. The present work has as objective to optimize the NEC synthesis process by means of the electric arc method which uses alternating current to high frequencies (HF), obtaining relatively clean products; that is to say, it hardly presents amorphous material neither impurities. They stand out the obtaining of carbon nano fibers (NFC) by means of a luminescent-arc discharge, in a gas mixture He-CH 4 with 34% at.Ni/10.32%at.Y like catalyst; to a frequency of 42 k Hz and low power (300 W). This method benefits the agglomeration of the particles in both electrodes due to the high frequencies. The time of duration of the process oscillates between 5 and 20 minutes. The obtained product was characterized by scanning electron microscopy (MEB), transmission electron microscopy (MET) to determine the type of obtained NEC and by X-ray diffraction analysis and Raman spectroscopy to determine the purity of the samples. The NFC are relatively free of amorphous coal. The surface and structural analysis indicates that the fibers have a half diameter of 80 nm. It is also made, a study by optical emission spectroscopy of the plasma using the Swan band to determine the temperature. (Author)

  3. Formation of three-dimensional nano-porous silver films and application toward electrochemical detection of hydrogen peroxide

    Energy Technology Data Exchange (ETDEWEB)

    Fan, Junpeng [Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials, Ministry of Education, Shandong University, Jinan 250061 (China); Bian, Xiufang, E-mail: xfbian@sdu.edu.cn [Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials, Ministry of Education, Shandong University, Jinan 250061 (China); Niu, Yuchao [Department of Materials Science and Engineering, Shandong Jianzhu University, Fengming Road, Lingang Development Zone, Jinan 250101 (China); Bai, Yanwen; Xiao, Xinxin; Yang, Chuncheng; Yang, Jianfei; Yang, Jinyue [Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials, Ministry of Education, Shandong University, Jinan 250061 (China)

    2013-11-15

    By using the chemically dealloying method, three-dimensional nano-porous silver films (3-D NPSFs) are fabricated into a novel sensor for detecting hydrogen peroxide. The precursor films are prepared by high vacuum magnetron co-sputtering. High-resolution transmission electron microscope (HRTEM) and scanning electron microscope (SEM) are taken to investigate the structure and the micro morphology of the precursor films and nano-porous films. We find that the precursor films are composed of glassy matrix and nanocrystallines. After dealloying, the films exhibit a combination of homogenously distributed pores and silver filaments, and exhibit an open, three dimensional bicontinuous interpenetrating ligament–channel structure. Thickness and morphology of the films can be easily controlled by the sputtering time and alloy composition of the precursor films, respectively. In addition, NPSFs show a good linear responding for the concentration of hydrogen peroxide in phosphate buffered solutions, which indicates NPSFs could be a promising electrochemical material for hydrogen peroxide detection.

  4. Surface study of nano-template anodic porous alumina pre-irradiated by ArF laser

    International Nuclear Information System (INIS)

    Jaleh, B.; Saramad, S.; Farshchi-Tabrizi, M.

    2009-01-01

    Nano-porous alumina membranes have widely used as matrix for the fabrication of nanomaterials for many applications including quantum-dot arrays, magnetic storage devices and composites for catalysis, due to their remarkable hardness, thermal and anti corrupted stability, uniform pore size and high pore density. In this experiment three sets of aluminum samples were chosen for fabrication nano-porous anodic alumina. One set has select for laser cleaning before chemical treatment and the two others with and without chemical treatment without laser irradiation. Anodic aluminum oxide (AAO) films were characterized with Scanning Electron Microscope (SEM) and Atomic Force Microscope (AFM) micrograph and the SEM results were analyzed by Linear-Angular Fast Fourier Transform (LA-FFT) technique to investigate the arrangement and ordering of pores. According to these results the laser irradiated sample has much better regularity in comparison with the usual one.

  5. Highly-sensitive electrochemical sensing platforms for food colourants based on the property-tuning of porous carbon.

    Science.gov (United States)

    Cheng, Qin; Xia, Shanhong; Tong, Jianhua; Wu, Kangbing

    2015-08-05

    It is very challenging to develop highly-sensitive analytical platforms for toxic synthetic colourants that widely added in food samples. Herein, a series of porous carbon (PC) was prepared using CaCO3 nanoparticles (nano-CaCO3) as the hard template and starch as the carbon precursor. Characterizations of scanning electron microscopy and transmission electron microscopy indicated that the morphology and porous structure were controlled by the weight ratio of starch and nano-CaCO3. The electrochemical behaviours of four kinds of widely-used food colourants, Sunset yellow, Tartrazine, Ponceau 4R and Allura red, were studied. On the surface of PC samples, the oxidation signals of colourants enhanced obviously, and more importantly, the signal enhancement abilities of PC were also dependent on the starch/nano-CaCO3 weight ratio. The greatly-increased electron transfer ability and accumulation efficiency were the main reason for the enhanced signals of colourants, as confirmed by electrochemical impedance spectroscopy and chronocoulometry. The prepared PC-2 sample by 1:1 starch/nano-CaCO3 weight ratio was more active for the oxidation of food colourtants, and increased the signals by 89.4-fold, 79.3-fold, 47.3-fold and 50.7-fold for Sunset yellow, Tartrazine, Ponceau 4R and Allura red. As a result, a highly-sensitive electrochemical sensing platform was developed, and the detection limits were 1.4, 3.5, 2.1 and 1.7 μg L(-1) for Sunset yellow, Tartrazine, Ponceau 4R and Allura red. The practical application of this new sensing platform was demonstrated using drink samples, and the detected results consisted with the values that obtained by high-performance liquid chromatography. Copyright © 2015 Elsevier B.V. All rights reserved.

  6. Porous structured niobium pentoxide/carbon complex for lithium-ion intercalation pseudocapacitors

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Guoming; Li, Heshun; Gao, Lixin [School of Environmental and Chemical Engineering, Shanghai University of Electric Power, Shanghai 200090 (China); Zhang, Daquan, E-mail: zhangdaquan@shiep.edu.cn [School of Environmental and Chemical Engineering, Shanghai University of Electric Power, Shanghai 200090 (China); Lin, Tong [Institute for Frontier Materials, Deakin University, Geelong, VIC 3216 (Australia)

    2016-12-15

    Highlights: • A simple one-pot in situ hydrothermal method to prepare T-Nb{sub 2}O{sub 5}/C. • The composite has well-dispersed C among nano-scale Nb{sub 2}O{sub 5}. • The composite has excellent large-current discharge property. • The composite has no obvious drop after 1000 cycles at 5 A g{sup −1}. - Abstract: A facile soft-templated synthesis of the niobium pentoxide/carbon (Nb{sub 2}O{sub 5}/C) from the polymerization of resorcinol with formaldehyde under the hydrothermal condition is introduced. This material has been characterized by X-ray diffraction (XRD), transmission electron microscope (TEM) and energy dispersive spectrometer (EDS) techniques. The carbon is well-dispersed in the nanostructure along with Nb{sub 2}O{sub 5} and the material is porous. The intimate contact between Nb{sub 2}O{sub 5} and carbon improves its conductivity. The electrochemical studies revealed that the porous Nb{sub 2}O{sub 5}/C displayed good pseudocapacitive response. The specific capacitance of the Nb{sub 2}O{sub 5}/C was 387 F g{sup −1} at 0.1 A g{sup −1} and 210 F g{sup −1} at 5 A g{sup −1}. The Nb{sub 2}O{sub 5}/C exhibits superior cycling performance, which can remain about 96% of its initial capacitance after 1000 cycles at 5 A g{sup −1}.

  7. Carbon nano structures: Production and characterization

    Science.gov (United States)

    Beig Agha, Rosa

    L'objectif de ce memoire est de preparer et de caracteriser des nanostructures de carbone (CNS -- Carbon Nanostructures, en licence a l'Institut de recherche sur l'hydrogene, Quebec, Canada), un carbone avec un plus grand degre de graphitisation et une meilleure porosite. Le Chapitre 1 est une description generale des PEMFCs (PEMFC -- Polymer Electrolyte Membrane Fuel Cell) et plus particulierement des CNS comme support de catalyseurs, leur synthese et purification. Le Chapitre 2 decrit plus en details la methode de synthese et la purification des CNS, la theorie de formation des nanostructures et les differentes techniques de caracterisation que nous avons utilises telles que la diffraction aux rayons-X (XRD -- X-ray diffraction), la microscopie electronique a transmission (TEM -- transmission electron microscope ), la spectroscopie Raman, les isothermes d'adsorption d'azote a 77 K (analyse BET, t-plot, DFT), l'intrusion au mercure, et l'analyse thermogravimetrique (TGA -- thermogravimetric analysis). Le Chapitre 3 presente les resultats obtenus a chaque etape de la synthese des CNS et avec des echantillons produits a l'aide d'un broyeur de type SPEXRTM (SPEX/CertiPrep 8000D) et d'un broyeur de type planetaire (Fritsch Pulverisette 5). La difference essentielle entre ces deux types de broyeur est la facon avec laquelle les materiaux sont broyes. Le broyeur de type SPEX secoue le creuset contenant les materiaux et des billes d'acier selon 3 axes produisant ainsi des impacts de tres grande energie. Le broyeur planetaire quant a lui fait tourner et deplace le creuset contenant les materiaux et des billes d'acier selon 2 axes (plan). Les materiaux sont donc broyes differemment et l'objectif est de voir si les CNS produits ont les memes structures et proprietes. Lors de nos travaux nous avons ete confrontes a un probleme majeur. Nous n'arrivions pas a reproduire les CNS dont la methode de synthese a originellement ete developpee dans les laboratoires de l'Institut de

  8. Tunable Graphitic Carbon Nano-Onions Development in Carbon Nanofibers for Multivalent Energy Storage

    Energy Technology Data Exchange (ETDEWEB)

    Schwarz, Haiqing L. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2016-01-01

    We developed a novel porous graphitic carbon nanofiber material using a synthesis strategy combining electrospinning and catalytic graphitization. RF hydrogel was used as carbon precursors, transition metal ions were successfully introduced into the carbon matrix by binding to the carboxylate groups of a resorcinol derivative. Transition metal particles were homogeneously distributed throughout the carbon matrix, which are used as in-situ catalysts to produce graphitic fullerene-like nanostructures surrounding the metals. The success design of graphitic carbons with enlarged interlayer spacing will enable the multivalent ion intercalation for the development of multivalent rechargeable batteries.

  9. Effects of pore size, implantation time and nano-surface properties on rat skin ingrowth into percutaneous porous titanium implants

    OpenAIRE

    Farrell, Brad J.; Prilutsky, Boris I.; Ritter, Jana M.; Kelley, Sean; Popat, Ketul; Pitkin, Mark

    2013-01-01

    The main problem of percutaneous osseointegrated implants is poor skin-implant integration, which may cause infection. This study investigated the effects of pore size (Small, 40–100 microns and Large, 100–160 microns), nanotubular surface treatment (Nano), and duration of implantation (3 and 6 weeks) on skin ingrowth into porous titanium. Each implant type was percutaneously inserted in the back of 35 rats randomly assigned to 7 groups. Implant extrusion rate was measured w...

  10. Optimization of Nano-Carbon Materials for Hydrogen Sorption

    Energy Technology Data Exchange (ETDEWEB)

    Yakobson, Boris I [Rice University

    2013-08-02

    Research undertaken has added to the understanding of several critical areas, by providing both negative answers (and therefore eliminating expensive further studies of unfeasible paths) and positive feasible options for storage. Theoretical evaluation of the early hypothesis of storage on pure carbon single wall nanotubes (SWNT) has been scrutinized with the use of comprehensive computational methods (and experimental tests by the Center partners), and demonstrated that the fundamentally weak binding energy of hydrogen is not sufficiently enhanced by the SWNT curvature or even defects, which renders carbon nanotubes not practical media. More promising direction taken was towards 3-dimensional architectures of high porosity where concurrent attraction of H2 molecule to surrounding walls of nano-scale cavities can double or even triple the binding energy and therefore make hydrogen storage feasible even at ambient or somewhat lower temperatures. An efficient computational tool has been developed for the rapid capacity assessment combining (i) carbon-foam structure generation, (ii) accurate empirical force fields, with quantum corrections for the lightweight H2, and (iii) grand canonical Monte Carlo simulation. This made it possible to suggest optimal designs for carbon nanofoams, obtainable via welding techniques from SWNT or by growth on template-zeolites. As a precursor for 3D-foams, we have investigated experimentally the synthesis of VANTA (Vertically Aligned NanoTube Arrays). This can be used for producing nano-foams. On the other hand, fluorination of VANTA did not show promising increase of hydrogen sorption in several tests and may require further investigation and improvements. Another significant result of this project was in developing a fundamental understanding of the elements of hydrogen spillover mechanisms. The benefit of developed models is the ability to foresee possible directions for further improvement of the spillover mechanism.

  11. Elastic nano-structure of diamond-like carbon (DLC)

    International Nuclear Information System (INIS)

    Ogiso, Hisato; Yoshida, Mikiko; Nakano, Shizuka; Yasui, Haruyuki; Awazu, Kaoru

    2006-01-01

    This research discusses the elastic nano-structure of diamond-like carbon (DLC) films. Two DLC film samples deposited by plasma based ion implantation (PBII) were prepared. The plasma generated by microwave (MW) was applied to one sample and the plasma by radio frequency (RF) to the other sample. The samples were evaluated for the elastic property image with nanometer resolution using scanning probe microscopy (SPM). The film surface deposited by RF-PBII was very flat and homogeneous in elastic property. In contrast, the film surface by MW-PBII was more uneven than that by RF-PBII and both the locally hard and the locally soft regions were found at the film surface. The size of the structure in elastic property is several tens nanometer. We conclude that the film probably contains nano-scale diamond phase

  12. Elastic nano-structure of diamond-like carbon (DLC)

    Energy Technology Data Exchange (ETDEWEB)

    Ogiso, Hisato [National Institute of Advanced Industrial Science and Technology (AIST), 1-2-1 Namiki, Tsukuba, Ibaraki 305-8564 (Japan); Yoshida, Mikiko [National Institute of Advanced Industrial Science and Technology (AIST), 1-2-1 Namiki, Tsukuba, Ibaraki 305-8564 (Japan); Nakano, Shizuka [National Institute of Advanced Industrial Science and Technology (AIST), 1-2-1 Namiki, Tsukuba, Ibaraki 305-8564 (Japan); Yasui, Haruyuki [Industrial Research Institute of Ishikawa (IRII), Ro-1, Tomizu-machi, Kanazawa, Ishikawa 920-0233 (Japan); Awazu, Kaoru [Industrial Research Institute of Ishikawa (IRII), Ro-1, Tomizu-machi, Kanazawa, Ishikawa 920-0233 (Japan)

    2006-01-15

    This research discusses the elastic nano-structure of diamond-like carbon (DLC) films. Two DLC film samples deposited by plasma based ion implantation (PBII) were prepared. The plasma generated by microwave (MW) was applied to one sample and the plasma by radio frequency (RF) to the other sample. The samples were evaluated for the elastic property image with nanometer resolution using scanning probe microscopy (SPM). The film surface deposited by RF-PBII was very flat and homogeneous in elastic property. In contrast, the film surface by MW-PBII was more uneven than that by RF-PBII and both the locally hard and the locally soft regions were found at the film surface. The size of the structure in elastic property is several tens nanometer. We conclude that the film probably contains nano-scale diamond phase.

  13. Utilization of porous carbons derived from coconut shell and wood in natural rubber

    Science.gov (United States)

    The porous carbons derived from cellulose are renewable and environmentally friendly. Coconut shell and wood derived porous carbons were characterized with elemental analysis, ash content, x-ray diffraction, infrared absorbance, particle size, surface area, and pore volume. The results were compared...

  14. Synthesis of Carbon nano structures by plasma discharge

    International Nuclear Information System (INIS)

    Jimenez L, M.L.

    2007-01-01

    Due to the great quantity of applications of the carbon nano structures (NEC) in diverse areas like: synthesis of super-resistant materials, hydrogen storage, nano sensors generation and nano catalysts, it has seen the necessity to generate new processes of synthesis of this materials as well as to already improve those existent. The present work has as objective to optimize the NEC synthesis process by means of the electric arc method which uses alternating current to high frequencies (HF), obtaining relatively clean products; that is to say, it hardly presents amorphous material neither sludges. They stand out the obtaining of carbon nano fibers (NFC) by means of a luminescent-arch discharge, in a gas mixture of He-CH 4 with 34% at. Ni/10.32% at.Y like catalyst; at a frequency of 42 kHz and low power (300 W). This method benefits the amass of the particles in both electrodes due to the high frequencies. The time of duration of the process oscillates between 5 and 20 minutes. The obtained product was characterized by scanning electron microscopy (MEB), transmission electron microscopy (MET) to determine the NEC type obtained and by X-ray diffraction analysis and Raman spectroscopy for determining the purity of the samples. The NFC is relatively free of amorphous coal. The surface and structural analysis indicates that the fibers have a half diameter of 80 nm. It is also made, a study by optical emission spectroscopy of plasma using the Swan band for determining the temperature. (Author)

  15. Preliminary biocompatible evaluation of nano-hydroxyapatite/polyamide 66 composite porous membrane

    Directory of Open Access Journals (Sweden)

    Yili Qu

    2010-06-01

    Full Text Available Yili Qu1,3, Ping Wang1,3, Yi Man1, Yubao Li2, Yi Zuo2, Jidong Li21State Key Laboratory of Oral Diseases, Sichuan University, Chengdu 610064, China; 2Research Center for Nano-Biomaterials, Analytical and Testing Center, Sichuan University, Chengdu 610064, China; 3These authors contributed equally to this workAbstract: Nano-hydroxyapatite/polyamide 66 (nHA/PA66 composite with good bioactivity and osteoconductivity was employed to develop a novel porous membrane with asymmetric structure for guided bone regeneration (GBR. In order to test material cytotoxicity and to investigate surface-dependent responses of bone-forming cells, the morphology, proliferation, and cell cycle of bone marrow stromal cells (BMSCs of rats cultured on the prepared membrane were determined. The polygonal and fusiform shape of BMSCs was observed by scanning electronic microscopy (SEM. The proliferation of BMSCs cultured on nHA/PA66 membrane tested by the MTT method (MTT: [3-{4,5-dimethylthiazol-2yl}-2,5-diphenyl-2H-tetrazoliumbromide] was higher than that of negative control groups for 1 and 4 days’ incubation and had no significant difference for 7 and 11 days’ culture. The results of cell cycle also suggested that the membrane has no negative influence on cell division. The nHA/PA66 membranes were then implanted into subcutaneous sites of nine Sprague Dawley rats. The wounds and implant sites were free from suppuration and necrosis in all periods. All nHA/PA66 membranes were surrounded by a fibrous capsule with decreasing thickness 1 to 8 weeks postoperatively. In conclusion, the results of the in vitro and in vivo studies reveal that nHA/PA66 membrane has excellent biocompatibility and indicate its use in guided tissue regeneration (GTR or GBR.Keywords: hydroxyapatite/polyamide, barrier membrane, biocompatibility, guided bone regeneration

  16. Nano-engineered composites: interlayer carbon nanotubes effect

    Energy Technology Data Exchange (ETDEWEB)

    Carley, Glaucio, E-mail: carleyone@hotmail.com [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil); Geraldo, Viviany; Oliveira, Sergio de [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Dept. de Fisica; Avila, Antonio Ferreira [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Dept. de Fisica

    2013-11-01

    The concept of carbon nanotube interlayer was successfully introduced to carbon fiber/epoxy composites. This new hybrid laminated composites was characterized by Raman spectroscopy, X-ray diffraction, scanning electron microscopy and tensile tests. An increase on peak stress close to 85% was witnessed when CNTs interlayer with 206.30 mg was placed to carbon fiber/epoxy laminates. The failure mechanisms are associated to CNTs distribution between and around carbon fibers. These CNTs are also responsible for crack bridging formation and the increase on peak stress. Initial stiffness is strongly affected by the CNT interlayer, however, changes on stiffness is associated to changes on nano/micro-structure due to damage. Three different behaviors can be described, i.e. for interlayers with Almost-Equal-To 60 mg of CNT the failure mode is based on cracks between and around carbon fibers, while for interlayers with CNT contents between 136 mg and 185 mg cracks were spotted on fibers and inside the CNT/matrix mix. Finally, the third failure mechanism is based on carbon fiber breakage, as a strong interface between CNT/matrix mix and carbon fibers is observed. (author)

  17. Nano-engineered composites: interlayer carbon nanotubes effect

    International Nuclear Information System (INIS)

    Carley, Glaucio; Geraldo, Viviany; Oliveira, Sergio de; Avila, Antonio Ferreira

    2013-01-01

    The concept of carbon nanotube interlayer was successfully introduced to carbon fiber/epoxy composites. This new hybrid laminated composites was characterized by Raman spectroscopy, X-ray diffraction, scanning electron microscopy and tensile tests. An increase on peak stress close to 85% was witnessed when CNTs interlayer with 206.30 mg was placed to carbon fiber/epoxy laminates. The failure mechanisms are associated to CNTs distribution between and around carbon fibers. These CNTs are also responsible for crack bridging formation and the increase on peak stress. Initial stiffness is strongly affected by the CNT interlayer, however, changes on stiffness is associated to changes on nano/micro-structure due to damage. Three different behaviors can be described, i.e. for interlayers with ≈ 60 mg of CNT the failure mode is based on cracks between and around carbon fibers, while for interlayers with CNT contents between 136 mg and 185 mg cracks were spotted on fibers and inside the CNT/matrix mix. Finally, the third failure mechanism is based on carbon fiber breakage, as a strong interface between CNT/matrix mix and carbon fibers is observed. (author)

  18. Study of the processes of carbonization and oxidation of porous silicon by Raman and IR spectroscopy

    International Nuclear Information System (INIS)

    Vasin, A. V.; Okholin, P. N.; Verovsky, I. N.; Nazarov, A. N.; Lysenko, V. S.; Kholostov, K. I.; Bondarenko, V. P.; Ishikawa, Y.

    2011-01-01

    Porous silicon layers were produced by electrochemical etching of single-crystal silicon wafers with the resistivity 10 Ω cm in the aqueous-alcohol solution of hydrofluoric acid. Raman spectroscopy and infrared absorption spectroscopy are used to study the processes of interaction of porous silicon with undiluted acetylene at low temperatures and the processes of oxidation of carbonized porous silicon by water vapors. It is established that, even at the temperature 550°C, the silicon-carbon bonds are formed at the pore surface and the graphite-like carbon condensate emerges. It is shown that the carbon condensate inhibits oxidation of porous silicon by water vapors and contributes to quenching of white photoluminescence in the oxidized carbonized porous silicon nanocomposite layer.

  19. Porous quasi three-dimensional nano-Mn3O4 + PbO2 composite as supercapacitor electrode material

    International Nuclear Information System (INIS)

    Dan Yuanyuan; Lin Haibo; Liu Xiaolei; Lu Haiyan; Zhao Jingzhe; Shi Zhan; Guo Yupeng

    2012-01-01

    Highlights: ► We prepare nano-PbO 2 + Mn 3 O 4 composite material by composite deposition method. ► The nano-PbO 2 + Mn 3 O 4 composite has porous quasi three-dimensional structure. ► Maximum electrochemically effective area (R F ) of the composite is 72. ► The composite shows high specific capacitance up to ∼340 F g −1 . ► A general knowledge of the pesudocapacitance behavior of the composite is acquired. - Abstract: Nano-Mn 3 O 4 + PbO 2 composite electrode materials with different compositions are prepared by anodic composite electrodeposition in Pb 2+ plating solution containing suspended nano-Mn 3 O 4 particles (40–60 nm). The particles are synthesized via one-step homogeneous precipitation at low temperature. The composite materials are characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM) analyses. The results indicate that the composite composed of γ-Mn 3 O 4 and β-PbO 2 is porous and quasi three-dimensional (3D), and its maximum electrochemically effective area ratio (R F ) is 72. The capacitance performance of the composite is determined by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and charge–discharge test. The composite shows a high specific capacitance up to 338 F g −1 .

  20. Fabrication and thermomechanical properties of nano-SiC/carbon nano-tubes composites

    International Nuclear Information System (INIS)

    Lanfant, Briac

    2014-01-01

    Ceramic carbides materials such as SiC, due to their refractory nature and their low neutron absorption are believed to be promising candidates for high temperature nuclear or aerospace applications. However, SiC brittleness has limited its structural application. In this context this work examines in a first part the possibilities to perform dense nano-structured SiC matrix by SPS without the use of sintering additive. Indeed a reduction of grain size (below 100 nm) accompanied by a high final density seem to be the solutions to counteract the brittleness and thus to improve mechanical properties. Dense (95%) and nano-structured (grain size around 100 nm) SiC samples were obtained thanks to the realization of an effective dispersion technique and the study on the sintering parameters effect. High hardness (2200 Hv) and decent fracture toughness (3.0 MPa.m1/2) were achieved. This first work also showed the preponderant influence of recurrent pollutants (oxygen and carbon) found in SiC powders on the final microstructure and mechanical properties of sintered samples. The oxygen as silica or silicon oxycarbide seems to promote densification mechanisms while free carbon (3.5 %wt) causes lower grain size and densification state. Mechanical properties with carbon are also negatively impacted (950 Hv and 2.4 MPa.m1/2). Such degradation is due by the specific localization of carbon structure between the grains. In return of the expected mechanical properties improvement by reducing the grain size, the thermal conductivity is drastically decrease of due to the phonon scattering at the grain boundaries. With the aim of reducing this effect, a second study was initiated by introducing multi-walled carbon nano-tubes (MWCNTs) into the SiC matrix. The MWCNTs by exhibiting a high toughness could also help to enhance the mechanical properties. Green bodies with different amounts of well dispersed MWCNTs (0 %wt to 5 %wt) were realized. Like free carbon, MWCNTs are located between

  1. Effects of Two Purification Pretreatments on Electroless Copper Coating over Single-Walled Carbon Nano tubes

    International Nuclear Information System (INIS)

    Zheng, Z.; Li, L.; Dong, Sh.; Li, Sh.; Xiao, A.; Sun, Sh.

    2014-01-01

    To achieve the reinforcement of copper matrix composite by single-walled carbon nano tubes, a three-step-refluxing purification of carbon nano tubes sample with HNO 3 -NaOH-HCl was proposed and demonstrated. A previously reported purification process using an electromagnetic stirring with H 2 O 2 /HCl mixture was also repeated. Then, the purified carbon nano tubes were coated with copper by the same electroless plating process. At the end, the effects of the method on carbon nano tubes themselves and on copper coating were determined by transmission electron microscope spectroscopy, scanning electron microscope spectroscopy, X-ray diffractometry, thermogravimetric analysis, Fourier transformed infrared spectroscopy, and energy dispersive spectrometry. It was clearly confirmed that both of the two processes could remove most of iron catalyst particles and carbonaceous impurities without significant damage to carbon nano tubes. The thermal stability of the sample purified by H 2 O 2 /HCl treatment was slightly higher than that purified by HNO 3 -NaOH-HCl treatment. Nevertheless, the purification by HNO 3 -NaOH-HCl treatment was more effective for carboxyl functionalization on nano tubes than that by H 2 O 2 /HCl treatment. The Cu-coating on carbon nano tubes purified by both purification processes was complete, homogenous, and continuous. However, the Cu-coating on carbon nano tubes purified by H 2 O 2 /HCl was oxidized more seriously than those on carbon nano tubes purified by HNO 3 -NaOH-HCl treatment.

  2. Elastic properties of porous low-k dielectric nano-films

    Science.gov (United States)

    Zhou, W.; Bailey, S.; Sooryakumar, R.; King, S.; Xu, G.; Mays, E.; Ege, C.; Bielefeld, J.

    2011-08-01

    Low-k dielectrics have predominantly replaced silicon dioxide as the interlayer dielectric for interconnects in state of the art integrated circuits. In order to further reduce interconnect RC delays, additional reductions in k for these low-k materials are being pursued via the introduction of controlled levels of porosity. The main challenge for such dielectrics is the substantial reduction in elastic properties that accompanies the increased pore volume. We report on Brillouin light scattering measurements used to determine the elastic properties of these films at thicknesses well below 200 nm, which are pertinent to their introduction into present ultralarge scale integrated technology. The observation of longitudinal and transverse standing wave acoustic resonances and their transformation into traveling waves with finite in-plane wave vectors provides for a direct non-destructive measure of the principal elastic constants that characterize the elastic properties of these porous nano-scale films. The mode dispersion further confirms that for porosity levels of up to 25%, the reduction in the dielectric constant does not result in severe degradation in the Young's modulus and Poisson's ratio of the films.

  3. Effects of Solution Chemistry on Nano-Bubbles Transport in Saturated Porous Media

    Science.gov (United States)

    Hamamoto, S.; Takemura, T.; Suzuki, K.; Nihei, N.; Nishimura, T.

    2017-12-01

    Nano-bubbles (NBs) have a considerable potential for the remediation of soil and groundwater contaminated by organic compounds, especially when used in conjunction with bioremediation technologies. Understanding the transport mechanisms of NBs in soils is essential to optimize NB-based remediation techniques. In this study, one-dimensional column transport experiments using glass beads with 0.1 mm size were conducted, where NBs created by oxygen gas at different pH and ionic strength were injected to the column at the constant flow rate. The NBs concentration in the effluent was quantified using a resonant mass measurement technique. Effects of solution chemistry of the NBs water on NB transport in the porous media were investigated. The results showed that attachment of NBs was enhanced under higher ionic strength and lower pH conditions, caused by the reduced repulsive force between NBs and glass beads. In addition, bubble size distributions in the effluents showed that relatively larger NBs were retained in the column. This trend was more significant at lower pH condition.

  4. Nano porous Adsorbent from Chitosan Interacted Montmorillonite for Dye-containing Wastewater Treatment

    International Nuclear Information System (INIS)

    Siriphannon, P.; Monvisade, P.

    2011-01-01

    Chitosan intercalated montmorillonite (Chi-MMT) was prepared by mixing 2 wt% of chitosan solution with sodium mont-morillonite (Na + -MMT) suspension at 60 degree Celsius for 24 hours. The Na + ions in Na + -MMT were completely exchanged with -NH 3 + ions of chitosan, resulting in the intercalation of chitosan into the MMT layer. The chitosan intercalation brought about the expansion of d 001 of Na + -MMT from 1.23 nm to 1.42 - >2.21 nm of the Chi-MMT. The existence of the intercalated-chitosan and large pore size could significantly increase the adsorption capacity of Chi-MMT from those of the starting materials, for example Na + -MMT and chitosan. The adsorption capacity of Chi-MMT adsorbent was equal to 4.9 mg/ g for acid red 91 (AR91) with initial dye concentration of 50 mg/ L, 45.9 mg/ g for basic yellow 1 (BY1) and 15.0 mg/ g for reactive orange 16 (RO16) with initial dye concentration of 500 mg/ L. These results indicated the competency of Chi-MMT nano porous adsorbent for treatment of wastewater containing various kinds of dyestuffs. (author)

  5. Design and synthesis of three-dimensional hierarchical ordered porous carbons for supercapacitors

    International Nuclear Information System (INIS)

    Zhao, Qinglan; Wang, Xianyou; Liu, Jing; Wang, Hao; Zhang, Youwei; Gao, Jiao; Lu, Qun; Zhou, Heye

    2015-01-01

    Highlights: • The 3D HOPCs are prepared by a facile templating method. • The pore structure of the 3D HOPCs can be effectively controllable. • The 3D HOPCs show exellent supercapacitive performances. • The high specific capacitance of 247 F g −1 is achieved. - Abstract: Three-dimensional hierarchical ordered porous carbons (3D HOPCs) have been successfully prepared through templating method using silica sphere nano-array as a hard template, triblock copolymer P123 as a soft template and sucrose as a carbon source, and used as the electrode materials for supercapacitors. The structure, morphology and physicochemical properties of the as-prepared 3D HOPCs are characterized by nitrogen adsorption–desorption isotherm, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and cyclic voltammetry (CV), galvanostatic charge–discharge (GCD) tests, and cycle life measurements. The results show that the 3D HOPCs possess well-interconnected 3D hierarchical ordered porous structure. Especially, the 3D HOPC-80, of which the pore size is 4.01 nm, shows the specific surface area of 1182 m 2 g −1 and a specific capacitance of 247 F g −1 at the current density of 1 A g −1 . Besides, the supercapacitors based on 3D HOPCs exhibit excellent rate performance, high energy densities of 7.5 W h kg −1 and 5.8 W h kg −1 at the power densities of 500 W kg −1 and 10000 W kg −1 , respectively. Moreover, the supercapacitors using 3D HOPCs as electrode materials hold high capacitance retentions over 91% even after 10000 cycles

  6. Stable electroluminescence from passivated nano-crystalline porous silicon using undecylenic acid

    Science.gov (United States)

    Gelloz, B.; Sano, H.; Boukherroub, R.; Wayner, D. D. M.; Lockwood, D. J.; Koshida, N.

    2005-06-01

    Stabilization of electroluminescence from nanocrystalline porous silicon diodes has been achieved by replacing silicon-hydrogen bonds terminating the surface of nanocrystalline silicon with more stable silicon-carbon (Si-C) bonds. Hydrosilylation of the surface of partially and anodically oxidized porous silicon samples was thermally induced at about 90 °C using various different organic molecules. Devices whose surface have been modified with stable covalent bonds shows no degradation in the EL efficiency and EL output intensity under DC operation for several hours. The enhanced stability can be attributed to the high chemical resistance of Si-C bonds against current-induced surface oxidation associated with the generation of nonradiative defects. Although devices treated with 1-decene exhibit reduced EL efficiency and brightness compared to untreatred devices, other molecules, such as ethyl-undecylenate and particularly undecylenic acid provide stable and more efficient visible electroluminescence at room temperature. Undecylenic acid provides EL brightness as high as that of an untreated device.

  7. Stable electroluminescence from passivated nano-crystalline porous silicon using undecylenic acid

    Energy Technology Data Exchange (ETDEWEB)

    Gelloz, B.; Sano, H.; Koshida, N. [Dept. Elec. and Elec. Eng., Tokyo Univ. of A and T, Koganei, Tokyo 184-8588 (Japan); Boukherroub, R. [Laboratoire de Physique de la Matiere Condensee, Ecole Polytechnique, Route de Saclay, 91128 Palaiseau (France); Wayner, D.D.M.; Lockwood, D.J. [National Research Council, Ottawa (Canada)

    2005-06-01

    Stabilization of electroluminescence from nanocrystalline porous silicon diodes has been achieved by replacing silicon-hydrogen bonds terminating the surface of nanocrystalline silicon with more stable silicon-carbon (Si-C) bonds. Hydrosilylation of the surface of partially and anodically oxidized porous silicon samples was thermally induced at about 90 C using various different organic molecules. Devices whose surface have been modified with stable covalent bonds shows no degradation in the EL efficiency and EL output intensity under DC operation for several hours. The enhanced stability can be attributed to the high chemical resistance of Si-C bonds against current-induced surface oxidation associated with the generation of nonradiative defects. Although devices treated with 1-decene exhibit reduced EL efficiency and brightness compared to untreated devices, other molecules, such as ethyl-undecylenate and particularly undecylenic acid provide stable and more efficient visible electroluminescence at room temperature. Undecylenic acid provides EL brightness as high as that of an untreated device. (copyright 2005 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  8. Lignocellulose-derived porous phosphorus-doped carbon as advanced electrode for supercapacitors

    Science.gov (United States)

    Yi, Jianan; Qing, Yan; Wu, ChuTian; Zeng, Yinxiang; Wu, Yiqiang; Lu, Xihong; Tong, Yexiang

    2017-05-01

    Engineering porous heteroatom-doped carbon nanomaterials with remarkable capacitive performance is highly attractive. Herein, a simple and smart method has been developed to synthesize phosphorus (P) doped carbon with hierarchical porous structure derived from lignocellulose. Hierarchically porous P doped carbon is readily obtained by the pyrolysis of lignocellulose immersed in ZnCl2/NaH2PO4 aqueous solution, and exhibits excellent capacitive properties. The as-obtained P doped porous carbon delivers a significant capacitance of 133 F g-1 (146 mF cm-2) at a high current density of 10 A g-1 with outstanding rate performance. Furthermore, the P doped carbon electrode yields a long-term cycling durability with more than 97.9% capacitance retention after 10000 cycles as well. A symmetric supercapacitor with a maximum energy density of 4.7 Wh kg-1 is also demonstrated based on these P doped carbon electrodes.

  9. Hierarchically porous carbon/polyaniline hybrid for use in supercapacitors.

    Science.gov (United States)

    Joo, Min Jae; Yun, Young Soo; Jin, Hyoung-Joon

    2014-12-01

    A hierarchically porous carbon (HPC)/polyaniline (PANI) hybrid electrode was prepared by the polymerization of PANI on the surface of the HPC via rapid-mixing polymerization. The surface morphologies and chemical composition of the HPC/PANI hybrid electrode were characterized using transmission electron microscopy and X-ray photoelectron spectroscopy (XPS), respectively. The surface morphologies and XPS results for the HPC, PANI and HPC/PANI hybrids indicate that PANI is coated on the surface of HPC in the HPC/PANI hybrids which have two different nitrogen groups as a benzenoid amine (-NH-) peak and positively charged nitrogen (N+) peak. The electrochemical performances of the HPC/PANI hybrids were analyzed by performing cyclic voltammetry and galvanostatic charge-discharge tests. The HPC/PANI hybrids showed a better specific capacitance (222 F/g) than HPC (111 F/g) because of effect of pseudocapacitor behavior. In addition, good cycle stabilities were maintained over 1000 cycles.

  10. Supercritical carbon dioxide behavior in porous silica aerogel

    International Nuclear Information System (INIS)

    Ciccariello, Salvino; Melnichenko, Yuri B.; He, Lilin

    2011-01-01

    Analysis of the tails of the small-angle neutron scattering (SANS) intensities relevant to samples formed by porous silica and carbon dioxide at pressures ranging from 0 to 20 MPa and at temperatures of 308 and 353 K confirms that the CO2 fluid must be treated as a two-phase system. The first of these phases is formed by the fluid closer to the silica wall than a suitable distance (delta) and the second by the fluid external to this shell. The sample scattering-length densities and shell thicknesses are determined by the Porod invariants and the oscillations observed in the Porod plots of the SANS intensities. The resulting matter densities of the shell regions (thickness 15-35 (angstrom)) are approximately equal, while those of the outer regions increase with pressure and become equal to the bulk CO2 at the higher pressures only in the low-temperature case.

  11. Synthesis of carbon nanotubes and porous carbons from printed circuit board waste pyrolysis oil

    International Nuclear Information System (INIS)

    Quan Cui; Li Aimin; Gao Ningbo

    2010-01-01

    The possibility and feasibility of using pyrolysis oil from printed circuit board (PCB) waste as a precursor for advanced carbonaceous materials is presented. The PCB waste was first pyrolyzed in a laboratory scale fixed bed reactor at 600 deg. C to prepare pyrolysis oil. The analysis of pyrolysis oil by gas chromatography-mass spectroscopy indicated that it contained a very high proportion of phenol and phenol derivatives. It was then polymerized in formaldehyde solution to synthesize pyrolysis oil-based resin which was used as a precursor to prepare carbon nanotubes (CNTs) and porous carbons. Scanning electron microscopy and transmission microscopy investigation showed that the resulting CNTs had hollow cores with outer diameter of ∼338 nm and wall thickness of ∼86 nm and most of them were filled with metal nanoparticles or nanorods. X-ray diffraction reveals that CNTs have an amorphous structure. Nitrogen adsorption isotherm analysis indicated the prepared porous carbons had a Brunauer-Emmett-Teller surface area of 1214 m 2 /g. The mechanism of the formation of the CNTs and porous carbons was discussed.

  12. Nano Materials

    International Nuclear Information System (INIS)

    Jin, In Ju; Lee, Ik Mo; Kwon, Yeung Gu

    2006-02-01

    This book introduces background of nano science such as summary, plenty room at the bottom, access way to nano technique, nanoparticles using bottom-up method which are a marvel of nature, and modern alchemy : chemical synthesis of artificial nano structure, understanding of quantum mechanics, STM/AFM, nano metal powder, ceramic nanoparticles, nano structure film, manufacture of nanoparticles using reverse micelle method, carbon nano tube, sol-gel material, nano energy material, nano catalyst nano bio material technology and spintronics.

  13. Pumpkin-Derived Porous Carbon for Supercapacitors with High Performance.

    Science.gov (United States)

    Bai, Suying; Tan, Guangqun; Li, Xiaoqin; Zhao, Qian; Meng, Yan; Wang, Yujue; Zhang, Yongzhi; Xiao, Dan

    2016-06-21

    Pumpkin has been employed for the first time as a renewable, low-cost precursor for the preparation of porous carbon materials with excellent performance. Unlike most other precursors, pumpkin is rich in sugars and starch, and it has advantageous properties for large-scale production. The as-prepared materials adopted a unique morphology that consisted of numerous fused sphere-like carbon grains with a high specific surface area (2968 m(2)  g(-1) ), abundant micro and mesopores, and excellent electrochemical properties. The pumpkin-derived activated carbon (PAC) material not only exhibited a high specific capacitance of 419 F g(-1) , but also showed considerable cycling stability, with 93.6 % retention after 10 000 cycles. Moreover, a symmetrical supercapacitor that was based on PAC showed a high energy density of 22.1 W h kg(-1) in aqueous electrolyte. These superior properties demonstrate that PAC holds great promise for applications in electrochemical energy-storage devices. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. π -Plasmon model for carbon nano structures: Application to porphyrin

    International Nuclear Information System (INIS)

    Ha, Dao Thu; Anh, Chu Thuy; Nga, Do Thi; Thanh, Le Minh; Van, Tran Thi Thanh; Viet, Nguyen Ai

    2016-01-01

    In traditional concept, the optical properties of semiconductors and semimetals near their fundamental optical band gaps are attributed to single excitations (such electron-hole pairs, excitons...). In our earlier article, we proposed the collective mechanism of π -plasmons for optical properties of low dimensional carbon nano structures. A simple way to calculate the peak positions of UV-vis absorption spectra was pointed out and gave a good agreement with experimental data. In this work we analyze different schemas to calculate the UV-vis absorption peaks. A new parameter k which characterizes the dependence of schema on geometry and number of carbon sites is defined. As an example, the case of porphyrin was investigated. (paper)

  15. Characteristics of Sodium Polyacrylate/Nano-Sized Carbon Hydrogel for Biomedical Patch.

    Science.gov (United States)

    Park, Jong-Kyu; Seo, Sun-Kyo; Cho, Seungkwan; Kim, Han-Sung; Lee, Chi-Hwan

    2018-03-01

    Conductive hydrogels were prepared for biomedical patch in order to improve the electrical conductivity. Sodium polyacrylate and nano-sized carbon were mixed and fabricated by aqueous solution gelation process in various contents of nano-sized carbon with 0.1, 0.5, 1.0 and 2.0 wt%. Sodium polyacrylate/nano-sized carbon conductive hydrogels were investigated by molecular structure, surface morphology and electrical conductivity. The conductivity of the hydrogel/nano-sized carbon conductive hydrogel proved to be 10% higher than conductive hydrogel without nano-sized carbon. However, it was founded that conductive hydrogels with nano-sized carbon content from 0.5 up to 2.0 wt% were remarkably decreased. This may be due to the non-uniform distribution of nano-sized carbon, resulting from agglomerates of nano-sized carbon. The developed hydrogel is intended for use in the medical and cosmetic fields that is applicable to supply micro-current from device to human body.

  16. Flame synthesis of carbon nano onions using liquefied petroleum gas without catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Dhand, Vivek, E-mail: vivekdhand2012@gmail.com [Centre for Knowledge Management of Nanoscience and Technology, 12-5-32/8, Vijayapuri Colony, Tarnaka, Secunderabad-500 017, A.P (India); Prasad, J. Sarada; Rao, M. Venkateswara [Centre for Environment, Institute of Science and Technology, Jawaharlal Nehru Technological University, Kukatpally, Hyderabad 500 085 (India); Bharadwaj, S. [Department of Physics, CVR College of Engineering and Osmania University, Hyderabad 501510, A.P (India); Anjaneyulu, Y. [TLGVRC, Jackson State University, JSU Box 18739, Jackson, MS 39217-0939 (United States); Jain, Pawan Kumar [International Advanced Research Centre for Powder Metallurgy and New Materials (ARCI), Balapur PO, Hyderabad 500005, Andhra Pradesh (India)

    2013-03-01

    Densely agglomerated, high specific surface area carbon nano onions with diameter of 30-40 nm have been synthesized. Liquefied petroleum gas and air mixtures produced carbon nano onions in diffusion flames without catalyst. The optimized oxidant to fuel ratio which produces carbon nano onions has been found to be 0.1 slpm/slpm. The experiment yielded 70% pure carbon nano onions with a rate of 5 g/h. X-ray diffraction, high-resolution electron microscopy and Raman spectrum reveal the densely packed sp{sup 2} hybridized carbon with (002) semi-crystalline hexagonal graphite reflection. The carbon nano onions are thermally stable up to 600 Degree-Sign C. - Highlights: Black-Right-Pointing-Pointer Flame synthesized carbon nano onions with 30-40 nm diameters. Black-Right-Pointing-Pointer LPG/air, diffusion type flame used in absence of catalyst to produce nano onions. Black-Right-Pointing-Pointer Carbon nano onion production rate is 5 g/hr and with 70% purity.

  17. Synthesis of Carbon Nano tubes: A Revolution in Material Science for the Twenty-First Century

    International Nuclear Information System (INIS)

    Allaf, Abd. W.

    2003-01-01

    The aim of this work is to explain the preparation procedures of single walled carbon nano tubes using arc discharge technique. The optimum conditions of carbon nano tubes synthesis are given. It should be pointed out that this sort of materials would be the twenty-first century materials

  18. Hierarchical porous carbon derived from Allium cepa for supercapacitors through direct carbonization method with the assist of calcium acetate

    KAUST Repository

    Xu, Jinhui; Zhang, Wenli; Hou, Dianxun; Huang, Weimin; Lin, Haibo

    2017-01-01

    In this paper, a direction carbonization method was used to prepare porous carbon from Allium cepa for supercapacitor applications. In this method, calcium acetate was used to assist carbonization process. Scanning electron microscope (SEM) and N2 adsorption/desorption method were used to characterize the morphology, Brunauer-Emmett-Teller (BET) specific surface area and pore size distribution of porous carbon derived from Allium cepa (onion derived porous carbon, OPC). OPC is of hierarchical porous structure with high specific surface area and relatively high specific capacitance. OPC possesses relatively high specific surface area of 533.5 m2/g. What’s more, OPC possesses a specific capacitance of 133.5 F/g at scan rate of 5 mV/s.

  19. Hierarchical porous carbon derived from Allium cepa for supercapacitors through direct carbonization method with the assist of calcium acetate

    KAUST Repository

    Xu, Jinhui

    2017-11-02

    In this paper, a direction carbonization method was used to prepare porous carbon from Allium cepa for supercapacitor applications. In this method, calcium acetate was used to assist carbonization process. Scanning electron microscope (SEM) and N2 adsorption/desorption method were used to characterize the morphology, Brunauer-Emmett-Teller (BET) specific surface area and pore size distribution of porous carbon derived from Allium cepa (onion derived porous carbon, OPC). OPC is of hierarchical porous structure with high specific surface area and relatively high specific capacitance. OPC possesses relatively high specific surface area of 533.5 m2/g. What’s more, OPC possesses a specific capacitance of 133.5 F/g at scan rate of 5 mV/s.

  20. Integration of Porous Carbon Nanowrinkles into Carbon Micropost Array for Microsupercapacitors

    Directory of Open Access Journals (Sweden)

    Shuang Xi

    2018-01-01

    Full Text Available Porous carbon nanowrinkles (PCW coated on carbon micropost (CMP arrays were successfully fabricated via three-step process, which took advantages of the large difference in elastic moduli between PCW and the raw material of CMP. The effect of nanowrinkle integration on the electrochemical performances was investigated, showing an improved electrochemical performance. The electrode also shows excellent cycling stability, which retains 84% of its initial discharge capacitance after 1700 cycles with >90% Coulombic efficiency. This enhanced electrochemical performance is ascribed to the synergistic effect of enlarged surface area and porous structure of PCW. The obtained PCW/CMP compositing electrode with the advantages of low cost and easy scaling-up has great potential for on-chip supercapacitors.

  1. Influence of porous texture and surface chemistry on the CO₂ adsorption capacity of porous carbons: acidic and basic site interactions.

    Science.gov (United States)

    Sánchez-Sánchez, Angela; Suárez-García, Fabián; Martínez-Alonso, Amelia; Tascón, Juan M D

    2014-12-10

    Doped porous carbons exhibiting highly developed porosity and rich surface chemistry have been prepared and subsequently applied to clarify the influence of both factors on carbon dioxide capture. Nanocasting was selected as synthetic route, in which a polyaramide precursor (3-aminobenzoic acid) was thermally polymerized inside the porosity of an SBA-15 template in the presence of different H3PO4 concentrations. The surface chemistry and the porous texture of the carbons could be easily modulated by varying the H3PO4 concentration and carbonization temperature. Porous texture was found to be the determinant factor on carbon dioxide adsorption at 0 °C, while surface chemistry played an important role at higher adsorption temperatures. We proved that nitrogen functionalities acted as basic sites and oxygen and phosphorus groups as acidic ones toward adsorption of CO2 molecules. Among the nitrogen functional groups, pyrrolic groups exhibited the highest influence, while the positive effect of pyridinic and quaternary functionalities was smaller. Finally, some of these N-doped carbons exhibit CO2 heats of adsorption higher than 42 kJ/mol, which make them excellent candidates for CO2 capture.

  2. Surface functional groups in capacitive deionization with porous carbon electrodes

    Science.gov (United States)

    Hemmatifar, Ali; Oyarzun, Diego I.; Palko, James W.; Hawks, Steven A.; Stadermann, Michael; Santiago, Juan G.; Stanford Microfluidics Lab Team; Lawrence Livermore National Lab Team

    2017-11-01

    Capacitive deionization (CDI) is a promising technology for removal of toxic ions and salt from water. In CDI, an applied potential of about 1 V to pairs of porous electrodes (e.g. activated carbon) induces ion electromigration and electrostatic adsorption at electrode surfaces. Immobile surface functional groups play a critical role in the type and capacity of ion adsorption, and this can dramatically change desalination performance. We here use models and experiments to study weak electrolyte surface groups which protonate and/or depropotante based on their acid/base dissociation constants and local pore pH. Net chemical surface charge and differential capacitance can thus vary during CDI operation. In this work, we present a CDI model based on weak electrolyte acid/base equilibria theory. Our model incorporates preferential cation (anion) adsorption for activated carbon with acidic (basic) surface groups. We validated our model with experiments on custom built CDI cells with a variety of functionalizations. To this end, we varied electrolyte pH and measured adsorption of individual anionic and cationic ions using inductively coupled plasma mass spectrometry (ICP-MS) and ion chromatography (IC) techniques. Our model shows good agreement with experiments and provides a framework useful in the design of CDI control schemes.

  3. Photoemission studies of fluorine functionalized porous graphitic carbon

    Science.gov (United States)

    Ganegoda, Hasitha; Jensen, David S.; Olive, Daniel; Cheng, Lidens; Segre, Carlo U.; Linford, Matthew R.; Terry, Jeff

    2012-03-01

    Porous graphitic carbon (PGC) has unique properties desirable for liquid chromatography applications when used as a stationary phase. The polar retention effect on graphite (PREG) allows efficient separation of polar and non-polar solutes. Perfluorinated hydrocarbons however lack polarizabilty and display strong lipo- and hydrophobicity, hence common lipophilic and hydrophilic analytes have low partition coefficiency in fluorinated stationary phases. Attractive interaction between fluorinated stationary phase and fluorinated analytes results in strong retention compared to non-fluorinated analytes. In order to change the selectivities of PGC, it is necessary to develop a bonded PGC stationary phase. In this study, we have synthesized perfluorinated, PGC using hepatadecafluoro-1-iodooctane, under different temperature conditions. Surface functionalization of the raw material was studied using photoelectron spectroscopy (PES). Results indicate the existence of fluorine containing functional groups, -CF, -CF2 along with an intercalated electron donor species. Multiple oxygen functional groups were also observed, likely due to the presence of oxygen in the starting material. These oxygen species may be responsible for significant modifications to planer and tetrahedral carbon ratios.

  4. Photoemission studies of fluorine functionalized porous graphitic carbon

    Energy Technology Data Exchange (ETDEWEB)

    Ganegoda, Hasitha; Olive, Daniel; Cheng, Lidens; Segre, Carlo U.; Terry, Jeff [Department of Physics, Illinois Institute of Technology, Chicago, Illinois 60616 (United States); Jensen, David S.; Linford, Matthew R. [Department of Chemistry and Biochemistry, Brigham Young University, Provo, Utah 84602 (United States)

    2012-03-01

    Porous graphitic carbon (PGC) has unique properties desirable for liquid chromatography applications when used as a stationary phase. The polar retention effect on graphite (PREG) allows efficient separation of polar and non-polar solutes. Perfluorinated hydrocarbons however lack polarizabilty and display strong lipo- and hydrophobicity, hence common lipophilic and hydrophilic analytes have low partition coefficiency in fluorinated stationary phases. Attractive interaction between fluorinated stationary phase and fluorinated analytes results in strong retention compared to non-fluorinated analytes. In order to change the selectivities of PGC, it is necessary to develop a bonded PGC stationary phase. In this study, we have synthesized perfluorinated, PGC using hepatadecafluoro-1-iodooctane, under different temperature conditions. Surface functionalization of the raw material was studied using photoelectron spectroscopy (PES). Results indicate the existence of fluorine containing functional groups, -CF, -CF{sub 2} along with an intercalated electron donor species. Multiple oxygen functional groups were also observed, likely due to the presence of oxygen in the starting material. These oxygen species may be responsible for significant modifications to planer and tetrahedral carbon ratios.

  5. Characterization and H2-O2 reactivity of noble nano-metal tailored single wall nano-carbons

    International Nuclear Information System (INIS)

    K Kaneko; T Itoh; E Bekyarova; H Kanoh; S Utsumi; H Tanaka; M Yudasaka; S Iijima; S Iijima

    2005-01-01

    Full text of publication follows: Single wall carbon nano-tube (SWNT) and single wall carbon nano-horn (SWNH) have nano-spaces in their particles and the nano-spaces become open by oxidation. In particular, SWNH forms a unique colloidal structure which has micropores and meso-pores between the SWNH particles. Although non-treated SWNH colloids have quasi-one dimensional nano-pores [1], oxidized SWNH colloids have both of interstitial and internal nano-pores [2-5]. SWNH colloids show excellent supercritical methane storage ability [6], molecular sieving effect [7], and unique hydrogen adsorption characteristic [8]. Selective adsorptivity of SWNH colloids for H 2 and D 2 due to uncertainty principle of those molecules was shown [9-10]. As SWNH has no metallic impurities, we can study the effect of tailoring of metallic nano-particles on the surface activities of SWNH [11]. We tailored Pd or Pt nano-particles on SWNH and SWNH oxidized at 823 K (ox-SWNH) using poly[(2-oxo-pyrrolidine-1-yl)ethylene]. The oxidation of SWNH donates nano-scale windows to the single wall. The tailored metal amount was determined by TG analysis. TEM showed uniform dispersion of nano-metal particles of 2-3 nm in the diameter on SWNH. The nitrogen adsorption amount of SWNH oxidized decreases by tailoring, indicating that nano-particles are attached to the nano-scale windows. The electronic states of tailored metals were characterized by X-ray photoelectron spectroscopy. The surface activities of Pd tailored SWNH and ox-SWNH were examined for the reaction of hydrogen and oxygen near room temperature. The catalytic reactivities of Pd tailored SWNH and ox-SWNH were 4 times greater than that of Pd-dispersed activated carbon. The temperature dependence of the surface activity will be discussed with the relevance to the tube porosity. References [1] T. Ohba et al, J. Phys. Chem. In press. [2] S. Utsumi et al, J. Phys. Chem. In press. [3] C.- Min Yang, et al. Adv. Mater. In press. [4]C.M. Yang, J

  6. Synthesis of Cr-MOF derived porous carbon for hydrogen storage applications

    CSIR Research Space (South Africa)

    Musyoka, Nicholas M

    2014-07-01

    Full Text Available Over the recent years, applications of porous metal-organic frameworks (MOFs) in hydrogen storage have received increasing attention in the scientific community. Conversion of organic moiety in MOFs to porous carbon, as well as the use of MOFs as a...

  7. Functional Biomass Carbons with Hierarchical Porous Structure for Supercapacitor Electrode Materials

    International Nuclear Information System (INIS)

    Chen, Hao; Liu, Duo; Shen, Zhehong; Bao, Binfu; Zhao, Shuyan; Wu, Limin

    2015-01-01

    Highlights: • We successfully prepared bamboo-derived porous carbon with B and N co-doping. • This novel carbon exhibits significantly enhanced specific capacitance and energy density. • The highest specific capacitance exceeds those of most similar carbon materials. • Asymmetric supercapacitor based on this carbon shows satisfactory capacitive performance. - Abstract: This paper presents nitrogen and boron co-doped KOH-activated bamboo-derived carbon as a porous biomass carbon with utility as a supercapacitor electrode material. Owing to the high electrochemical activity promoted by the hierarchical porous structure and further endowed by boron and nitrogen co-doping, electrodes based on the as-obtained material exhibit significantly enhanced specific capacitance and energy density relative to those based on most similar materials. An asymmetric supercapacitor based on this novel carbon material demonstrated satisfactory energy density and electrochemical cycling stability.

  8. 3D hybrid-porous carbon derived from carbonization of metal organic frameworks for high performance supercapacitors

    Science.gov (United States)

    Bao, Weizhai; Mondal, Anjon Kumar; Xu, Jing; Wang, Chengyin; Su, Dawei; Wang, Guoxiu

    2016-09-01

    We report a rational design and synthesis of 3D hybrid-porous carbon with a hierarchical pore architecture for high performance supercapacitors. It contains micropores (<2 nm diameter) and mesopores (2-4 nm), derived from carbonization of unique porous metal organic frameworks (MOFs). Owning to the synergistic effect of micropores and mesopores, the hybrid-porous carbon has exceptionally high ion-accessible surface area and low ion diffusion resistance, which is desired for supercapacitor applications. When applied as electrode materials in supercapacitors, 3D hybrid-porous carbon demonstrates a specific capacitance of 332 F g-1 at a constant charge/discharge current of 500 mA g-1. The supercapacitors can endure more than 10,000 cycles without degradation of capacitance.

  9. Deposition and release kinetics of nano-TiO2 in saturated porous media: Effects of solution ionic strength and surfactants

    International Nuclear Information System (INIS)

    Godinez, Itzel G.; Darnault, Christophe J.G.; Khodadoust, Amid P.; Bogdan, Dorin

    2013-01-01

    The aggregation, transport and deposition kinetics (i.e. attachment and release) of TiO 2 nanoparticles (nano-TiO 2 ) were investigated as a function of ionic strength and the presence of anionic (sodium dodecylbenzene sulfonate, SDBS) and non-ionic (Triton X-100) surfactants in 100% critical micelle concentration (CMC). The electrolyte concentration of the suspensions dictated the kinetic stability of nano-TiO 2 thus influencing the transport and retention of the nanoaggregates in the saturated porous medium. With increasing ionic strength, the interaction between approaching nano-TiO 2 and nano-TiO 2 already deposited onto collectors surfaces seemed to be more favorable than the interaction between approaching nano-TiO 2 and bare collectors surfaces. The abrupt and gradual reduction in electrolyte concentration during the flushing cycles of the column experiments induced the release of previously deposited nano-TiO 2 suggesting attachment of nano-TiO 2 through secondary energy minimum. Highlights: ► This study focuses on aggregation, transport and deposition kinetics of nano-TiO 2 . ► Ionic strength and surfactants impact nano-TiO 2 transport in saturated porous media. ► Previously deposited nano-TiO 2 serve as preferential sites for subsequent deposition. ► Changes in solution chemistry cause nanodeposits to release a portion of nano-TiO 2 . -- Previously deposited nano-TiO 2 serve as preferential sites for subsequent deposition and changes in solution chemistry cause nanodeposits to release a portion of nano-TiO 2

  10. Effects of pore size, implantation time, and nano-surface properties on rat skin ingrowth into percutaneous porous titanium implants.

    Science.gov (United States)

    Farrell, Brad J; Prilutsky, Boris I; Ritter, Jana M; Kelley, Sean; Popat, Ketul; Pitkin, Mark

    2014-05-01

    The main problem of percutaneous osseointegrated implants is poor skin-implant integration, which may cause infection. This study investigated the effects of pore size (Small, 40-100 μm and Large, 100-160 μm), nanotubular surface treatment (Nano), and duration of implantation (3 and 6 weeks) on skin ingrowth into porous titanium. Each implant type was percutaneously inserted in the back of 35 rats randomly assigned to seven groups. Implant extrusion rate was measured weekly and skin ingrowth into implants was determined histologically after harvesting implants. It was found that all three types of implants demonstrated skin tissue ingrowth of over 30% (at week 3) and 50% (at weeks 4-6) of total implant porous area under the skin; longer implantation resulted in greater skin ingrowth (p skin integration with the potential for a safe seal. Copyright © 2013 Wiley Periodicals, Inc.

  11. Nano mechanical properties of carbon films modified by ion radiation

    International Nuclear Information System (INIS)

    Foerster, C.E.; Serbena, F.C.; Lepienski, C.M.; Odo, G.Y.; Zawislak, F.C.; Lopes, J.M.J.; Baptista, D.L.; Garcia, I.T.S.

    2000-01-01

    In present work it is measured hardness, Young modulus and friction coefficient values for different types of carbon films. These films were submitted to different ion bombardment conditions (energy and fluencies). The mechanical behavior was obtained by nano indentation technique and analyzed by the Oliver/Pharr method. For friction coefficient determination the nano scratch procedure is used. Pristine C 60 films (fullerenes) has a hardness of 0.33 GPa. After irradiation with different ions (He, N and Bi), the hardness raise to about 14 GPa and the Young modulus change from 20 to about 200 GPa. For photoresist film AZ-1350J irradiation with Ar and He change the hardness from 0.4 to about 14 GPa and the Young modulus raise from 4 to 80 GPa. In a-C-H the hardness change from 3.5 to 11 GPa when submitted to N irradiation. In PPA films the hardness value raise from 0.5 to 11 GPa after irradiation with Ar. These mechanical and tribological results were analyzed in terms of deposited energy by the ion irradiation and compared with those presented in the literature. (author)

  12. Fabrication of nano-electrode arrays of free-standing carbon nanotubes on nano-patterned substrate by imprint method

    Energy Technology Data Exchange (ETDEWEB)

    Chang, W.S., E-mail: paul@kimm.re.kr [Department of Nano Mechanics, Korea Institute of Machinery and Materials, 104 Sinseongno, Yuseong-gu Daejeon 305-343 (Korea, Republic of); Kim, J.W. [Gyeongbuk Hybrid Technology Institute, 36 Goeyeon-dong, Yeongcheon, Gyeongbuk 770-170 (Korea, Republic of); Choi, D.G. [Department of Nano Mechanics, Korea Institute of Machinery and Materials, 104 Sinseongno, Yuseong-gu Daejeon 305-343 (Korea, Republic of); Han, C.S. [Gyeongbuk Hybrid Technology Institute, 36 Goeyeon-dong, Yeongcheon, Gyeongbuk 770-170 (Korea, Republic of)

    2011-01-15

    The synthesis of isolated carbon nanotubes with uniform outer diameters and ordered spacing over wafer-scale areas was investigated for fabrication of nano-electrode arrays on silicon wafers for field emission and sensor devices. Multi-walled carbon nanotubes (MWCNTs) were grown on TiN electrode layer with iron catalyst patterned by nano-imprint lithography (NIL), which allows the precise placement of individual CNTs on a substrate. The proposed techniques, including plasma-enhanced chemical vapor deposition (PECVD) and NIL, are simple, inexpensive, and reproducible methods for fabrication of nano-scale devices in large areas. The catalyst patterns were defined by an array of circles with 200 nm in diameter, and variable lengths of pitch. The nano-patterned master and Fe catalyst were observed with good pattern fidelity over a large area by atomic force microscope (AFM) and scanning electron microscopy (SEM). Nano-electrodes of MWCNTs had diameters ranging from 50 nm to 100 nm and lengths of about 300 nm. Field emission tests showed the reducing ignition voltage as the geometry of nanotube arrays was controlled by catalyst patterning. These results showed a wafer-scale approach to the control of the size, pitch, and position of nano-electrodes of nanotubes for various applications including electron field-emission sources, electrochemical probes, functionalized sensor elements, and so on.

  13. Irreversible membrane fouling abatement through pre-deposited layer of hierarchical porous carbons

    KAUST Repository

    Hamad, Juma; Dua, Rubal; Kurniasari, Novita; Kennedy, Maria Dolores; Wang, Peng; Amy, Gary L.

    2014-01-01

    In this work, dual-templated hierarchical porous carbons (HPCs), produced from a coupled ice-hard templating approach, are shown to be a highly effective solution to the commonly occurring problem of irreversible fouling of low-pressure membranes

  14. Investigation on Nano composite Membrane of Multi walled Carbon Nano tube Reinforced Polycarbonate Blend for Gas Separation

    International Nuclear Information System (INIS)

    Kausar, A.

    2016-01-01

    Carbon nano tube has been explored as a nano filler in high performance polymeric membrane for gas separation. In this regard, nano composite membrane of polycarbonate (PC), poly(vinylidene fluoride-co-hexafluoropropylene) (PVFHFP), and multi walled carbon nano tube (MWCNT) was fabricated via phase inversion technique. Poly (ethylene glycol) (PEG) was employed for the compatibilization of the blend system. Two series of PC/PVFHFP/PEG were developed using purified P-MWCNT and acid functional A-MWCNT nano filler. Scanning and transmission electron micrographs have shown fine nano tube dispersion and wetting by matrix, compared with the purified system. Tensile strength and Young s modulus of PC/PVFHFP/PEG/MWCNT-A 1-5 were found to be in the range of 63.6-72.5 MPa and 110.6-122.1 MPa, respectively. The nano composite revealed 51% increase in Young s modulus and 28% increase in tensile stress relative to the pristine blend. The A-MWCNT was also effective in enhancing the perm selectivity αCO 2 /N 2 (31.2-39.9) of nano composite membrane relative to the blend membrane (21.6). The permeability ρCO 2 of blend was 125.6 barrer; however, the functional series had enhancedρCO 2 values ranging from 142.8 to 186.6 barrer. Moreover, A-MWCNT loading improved the gas diffusivity of PC/PVFHFP/PEG/MWCNT-A 1-5; however, filler content did not significantly influence the CO 2 and N 2 solubility.

  15. Hard template synthesis of porous carbon nitride materials with improved efficiency for photocatalytic CO_2 utilization

    International Nuclear Information System (INIS)

    Ovcharov, M.; Shcherban, N.; Filonenko, S.; Mishura, A.; Skoryk, M.; Shvalagin, V.; Granchak, V.

    2015-01-01

    Graphical abstract: - Highlights: • Porous carbon nitrides were obtained via bulk and matrix pyrolysis of melamine. • Carbon nitride obtained in MCF has the highest bandgap and photocatalytic activity. • Acetaldehyde was the major product of the photoreduction reaction of CO2. - Abstract: Porous carbon nitrides of different morphology were obtained via bulk and hard template (SBA-15 and MCF) pyrolysis of melamine. Matrix method allowed obtaining ordered porous C_3N_4 with higher bandgap (2.87 eV) in the contrary to the bulk sample (2.45 eV). Obtained carbon nitrides were found to be p-type semiconductors with catalytic activity towards photoreduction of carbon dioxide with water vapour. Carbon nitride obtained in MCF has the higher bandgap, developed surface, sponge-like morphology, spatially ordering and it's characterized by the highest photocatalytic activity.

  16. 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)

  17. Studies on the reactive melt infiltration of silicon and silicon-molybdenum alloys in porous carbon

    Science.gov (United States)

    Singh, M.; Behrendt, D. R.

    1992-01-01

    Investigations on the reactive melt infiltration of silicon and silicon-1.7 and 3.2 at percent molybdenum alloys into porous carbon preforms have been carried out by process modeling, differential thermal analysis (DTA) and melt infiltration experiments. These results indicate that the initial pore volume fraction of the porous carbon preform is a critical parameter in determining the final composition of the raction-formed silicon carbide and other residual phases. The pore size of the carbon preform is very detrimental to the exotherm temperatures due to liquid silicon-carbon reactions encountered during the reactive melt infiltration process. A possible mechanism for the liquid silicon-porous (glassy) carbon reaction has been proposed. The composition and microstructure of the reaction-formed silicon carbide has been discussed in terms of carbon preform microstructures, infiltration materials, and temperatures.

  18. Free-Standing Porous Carbon Nanofiber Networks from Electrospinning Polyimide for Supercapacitors

    Directory of Open Access Journals (Sweden)

    Bo Wang

    2016-01-01

    Full Text Available Free-standing porous carbon nanofiber networks (CFNs were synthesized by electrospinning method and carbonization procedure. We study the implementation of porous CFNs as supercapacitor electrodes and electrochemical measurements demonstrated that porous CFNs exhibit a specific capacitance (205 F/g at the scan rate of 5 mV/s with high flexibility and good rate capability performance (more than 70% of its initial capacitance from 5 mV/s to 200 mV/s. Furthermore, porous CFNs exhibited an excellent cycling stability (just 12% capacitance loss after 10,000 cycles. These results suggest that porous CFNs are very promising candidates as flexible supercapacitor electrodes.

  19. Monte-Carlo Simulation of Hydrogen Adsorption in Single-Wall Carbon Nano-Cones

    Directory of Open Access Journals (Sweden)

    Zohreh Ahadi

    2011-01-01

    Full Text Available The properties of hydrogen adsorption in single-walled carbon nano-cones are investigated in detail by Monte Carlo simulations. A great deal of our computational results show that the hydrogen storage capacity in single-walled carbon nano-cones is slightly smaller than the capacity of single-walled carbon nanotubes at any time at the same conditions. This indicates that the hydrogen storage capacity of single-walled carbon nano-cones is related to angles of carbon nano-cones. It seems that these type of nanotubes could not exceed the 2010 goal of 6 wt%, which is presented by the U.S. Department of Energy. In addition, these results are discussed in theory.

  20. The effect of atomic hydrogen adsorption on single-walled carbon nano tubes properties

    International Nuclear Information System (INIS)

    Jalili, S.; Majidi, R.

    2007-01-01

    We investigated the adsorption of hydrogen atoms on metallic single-walled carbon nano tubes using ab initio molecular dynamics method. It was found that the geometric structures and the electronic properties of hydrogenated SWNTs can be strongly changed by varying hydrogen coverage. The circular cross sections of the CNTs were changed with different hydrogen coverage. When hydrogen is chemisorbed on the surface of the carbon nano tube, the energy gap will be appeared. This is due to the degree of the Sp 3 hybridization, and the hydrogen coverage can control the band gap of the carbon nano tube

  1. Investigation of gas molecules adsorption on carbon nano tubes electric properties in tight binding model

    International Nuclear Information System (INIS)

    Moradian, R.; Mohammadi, Y.

    2007-01-01

    Based on tight binding model we investigated effects of bi-atomic molecules gas(in the general form denoted by X 2 )on single-walled carbon nano tubes electronic properties. We found for some specified values of hopping integrals and random on-site energies, adsorbed molecules bound states located inside of the (10,0) single-walled carbon nano tubes energy gap, where it is similar to the reported experimental results for O 2 adsorption while for other values there is no bound states inside of energy gap. This is similar to the N 2 adsorption on semiconductor single-walled carbon nano tubes.

  2. Synthesis and characterization of carbon nano fibers for its application in the adsorption of toxic gases

    International Nuclear Information System (INIS)

    Juanico L, J.A.

    2004-01-01

    The production of carbon nano fibers (CNF's) by diverse techniques as the electric arc, laser ablation, or chemical deposition in vapor phase, among other, they have been so far used from final of the 90's. However, the synthesis method by discharge Glow arc of alternating current and high frequency developed by Pacheco and collaborators, is a once alternative for its obtaining. In the plasma Application Laboratory (LAP) of the National Institute of Nuclear Research (INlN) it was designed and manufactured a reactor of alternating current and high frequency that produces a Glow arc able to synthesize carbon nano fibers. Its were carried out nano fibers synthesis with different catalysts to different proportions and with distinct conditions of vacuum pressure and methane flow until obtaining the best nano fibers samples and for it, this nano structures were characterized by Scanning and Transmission Electron Microscopy, X-ray Diffraction, Raman spectrometry and EDS spectrometry. Once found the optimal conditions for the nano fibers production its were contaminated with NO 2 toxic gas and it was determined if they present adsorption, for it was used the thermal gravimetric analysis technique. This work is divided in three parts, in the first one, conformed by the chapters 1, at the 3, they are considered the foundations of the carbon nano fibers, their history, their characteristics, growth mechanisms, synthesis techniques, the thermal gravimetric analysis principles and the adsorption properties of the nano fibers. In the second part, consistent of the chapters 4 and 5, the methodology of synthesis and characterization of the nano fibers is provided. Finally, in third part its were carried out the activation energy calculation, the adsorption of the CNF's is analyzed and the conclusions are carried out. The present study evaluates the adsorption of environmental gas pollutants as the nitrogen oxides on carbon nano fibers at environmental or near conditions. Also

  3. Highly porous activated carbons prepared from carbon rich Mongolian anthracite by direct NaOH activation

    Energy Technology Data Exchange (ETDEWEB)

    Byamba-Ochir, Narandalai [School of Chemical Engineering, Chonnam National University, 77 Yongbong-Ro, Gwangju 61186 (Korea, Republic of); Shim, Wang Geun [Department of Polymer Science and Engineering, Sunchon National University, 255 Jungang-Ro, Suncheon, Jeollanam-Do 57922 (Korea, Republic of); Balathanigaimani, M.S., E-mail: msbala@rgipt.ac.in [Department of Chemical Engineering, Rajiv Gandhi Institute of Petroleum Technology, Ratapur Chowk, Rae Bareli, 229316 Uttar Pradesh (India); Moon, Hee, E-mail: hmoon@jnu.ac.kr [School of Chemical Engineering, Chonnam National University, 77 Yongbong-Ro, Gwangju 61186 (Korea, Republic of)

    2016-08-30

    Highlights: • Highly porous carbon materials from Mongolian anthracite by chemical activation. • Cheaper and eco-friendly activation process has been employed. • Activated carbons with graphitic structure and energetically heterogeneous surface. • Surface hydrophobicity and porosity of the activated carbons can be controlled. - Abstract: Highly porous activated carbons (ACs) were prepared from Mongolian raw anthracite (MRA) using sodium hydroxide as an activation agent by varying the mass ratio (powdered MRA/NaOH) as well as the mixing method of chemical agent and powdered MRA. The specific BET surface area and total pore volume of the prepared MRA-based activated carbons (MACs) are in the range of 816–2063 m{sup 2}/g and of 0.55–1.61 cm{sup 3}/g, respectively. The pore size distribution of MACs show that most of the pores are in the range from large micropores to small mesopores and their distribution can be controlled by the mass ratio and mixing method of the activating agent. As expected from the intrinsic property of the MRA, the highly graphitic surface morphology of prepared carbons was confirmed from Raman spectra and transmission electron microscopy (TEM) studies. Furthermore the FTIR and XPS results reveal that the preparation of MACs with hydrophobic in nature is highly possible by controlling the mixing conditions of activating agent and powdered MRA. Based on all the results, it is suggested that the prepared MACs could be used for many specific applications, requiring high surface area, optimal pore size distribution, proper surface hydrophobicity as well as strong physical strength.

  4. Nano-Reinforcement of Interfaces in Prepreg-Based Composites Using a Carbon Nanotubes Spraying Method

    KAUST Repository

    Almuhammadi, Khaled

    2012-01-01

    of epoxy resins used as matrix materials for CFRP composites can be increased by the addition of nano-sized fillers such as Carbon nanotubes (CNTs). CNTs are particularly well suited for this purpose because of their nano-scale diameter and high aspect

  5. Formic Acid Oxidation over Hierarchical Porous Carbon Containing PtPd Catalysts

    Directory of Open Access Journals (Sweden)

    Elena Pastor

    2013-10-01

    Full Text Available The use of high surface monolithic carbon as support for catalysts offers important advantage, such as elimination of the ohmic drop originated in the interparticle contact and improved mass transport by ad-hoc pore design. Moreover, the approach discussed here has the advantage that it allows the synthesis of materials having a multimodal porous size distribution, with each pore size contributing to the desired properties. On the other hand, the monolithic nature of the porous support also imposes new challenges for metal loading. In this work, the use of Hierarchical Porous Carbon (HPC as support for PtPd nanoparticles was explored. Three hierarchical porous carbon samples (denoted as HPC-300, HPC-400 and HPC-500 with main pore size around 300, 400 and 500 nm respectively, are used as porous support. PtPd nanoparticles were loaded by impregnation and subsequent chemical reduction with NaBH4. The resulting material was characterized by EDX, XRD and conventional electrochemical techniques. The catalytic activity toward formic acid and methanol electrooxidation was evaluated by electrochemical methods, and the results compared with commercial carbon supported PtPd. The Hierarchical Porous Carbon support discussed here seems to be promising for use in DFAFC anodes.

  6. Oxygen-rich hierarchical porous carbon derived from artemia cyst shells with superior electrochemical performance.

    Science.gov (United States)

    Zhao, Yufeng; Ran, Wei; He, Jing; Song, Yanfang; Zhang, Chunming; Xiong, Ding-Bang; Gao, Faming; Wu, Jinsong; Xia, Yongyao

    2015-01-21

    In this study, three-dimensional (3D) hierarchical porous carbon with abundant functional groups is produced through a very simple low-cost carbonization of Artemia cyst shells. The unique hierarchical porous structure of this material, combining large numbers of micropores and macropores, as well as reasonable amount of mesopores, is proven favorable to capacitive behavior. The abundant oxygen functional groups from the natural carbon precursor contribute stable pseudocapacitance. As-prepared sample exhibits high specific capacitance (369 F g(-1) in 1 M H2SO4 and 349 F g(-1) in 6 M KOH), excellent cycling stability with capacitance retention of 100% over 10 000 cycles, and promising rate performance. This work not only describes a simple way to produce high-performance carbon electrode materials for practical application, but also inspires an idea for future structure design of porous carbon.

  7. Highly-sensitive electrochemical sensing platforms for food colourants based on the property-tuning of porous carbon

    International Nuclear Information System (INIS)

    Cheng, Qin; Xia, Shanhong; Tong, Jianhua; Wu, Kangbing

    2015-01-01

    It is very challenging to develop highly-sensitive analytical platforms for toxic synthetic colourants that widely added in food samples. Herein, a series of porous carbon (PC) was prepared using CaCO 3 nanoparticles (nano-CaCO 3 ) as the hard template and starch as the carbon precursor. Characterizations of scanning electron microscopy and transmission electron microscopy indicated that the morphology and porous structure were controlled by the weight ratio of starch and nano-CaCO 3 . The electrochemical behaviours of four kinds of widely-used food colourants, Sunset yellow, Tartrazine, Ponceau 4R and Allura red, were studied. On the surface of PC samples, the oxidation signals of colourants enhanced obviously, and more importantly, the signal enhancement abilities of PC were also dependent on the starch/nano-CaCO 3 weight ratio. The greatly-increased electron transfer ability and accumulation efficiency were the main reason for the enhanced signals of colourants, as confirmed by electrochemical impedance spectroscopy and chronocoulometry. The prepared PC-2 sample by 1:1 starch/nano-CaCO 3 weight ratio was more active for the oxidation of food colourtants, and increased the signals by 89.4-fold, 79.3-fold, 47.3-fold and 50.7-fold for Sunset yellow, Tartrazine, Ponceau 4R and Allura red. As a result, a highly-sensitive electrochemical sensing platform was developed, and the detection limits were 1.4, 3.5, 2.1 and 1.7 μg L −1 for Sunset yellow, Tartrazine, Ponceau 4R and Allura red. The practical application of this new sensing platform was demonstrated using drink samples, and the detected results consisted with the values that obtained by high-performance liquid chromatography. - Highlights: • PC samples with different morphology and electrochemical activities were prepared. • Highly sensitive electrochemical sensing platform was developed for food colourants. • The accuracy and practicability was testified to be good by HPLC

  8. Highly-sensitive electrochemical sensing platforms for food colourants based on the property-tuning of porous carbon

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Qin [Key Laboratory for Large-Format Battery Materials and System, Ministry of Education, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan, 430074 (China); Xia, Shanhong; Tong, Jianhua [State Key Laboratory of Transducer Technology, Institute of Electronics, Chinese Academy of Science, Beijing, 100190 (China); Wu, Kangbing, E-mail: kbwu@hust.edu.cn [Key Laboratory for Large-Format Battery Materials and System, Ministry of Education, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan, 430074 (China)

    2015-08-05

    It is very challenging to develop highly-sensitive analytical platforms for toxic synthetic colourants that widely added in food samples. Herein, a series of porous carbon (PC) was prepared using CaCO{sub 3} nanoparticles (nano-CaCO{sub 3}) as the hard template and starch as the carbon precursor. Characterizations of scanning electron microscopy and transmission electron microscopy indicated that the morphology and porous structure were controlled by the weight ratio of starch and nano-CaCO{sub 3}. The electrochemical behaviours of four kinds of widely-used food colourants, Sunset yellow, Tartrazine, Ponceau 4R and Allura red, were studied. On the surface of PC samples, the oxidation signals of colourants enhanced obviously, and more importantly, the signal enhancement abilities of PC were also dependent on the starch/nano-CaCO{sub 3} weight ratio. The greatly-increased electron transfer ability and accumulation efficiency were the main reason for the enhanced signals of colourants, as confirmed by electrochemical impedance spectroscopy and chronocoulometry. The prepared PC-2 sample by 1:1 starch/nano-CaCO{sub 3} weight ratio was more active for the oxidation of food colourtants, and increased the signals by 89.4-fold, 79.3-fold, 47.3-fold and 50.7-fold for Sunset yellow, Tartrazine, Ponceau 4R and Allura red. As a result, a highly-sensitive electrochemical sensing platform was developed, and the detection limits were 1.4, 3.5, 2.1 and 1.7 μg L{sup −1} for Sunset yellow, Tartrazine, Ponceau 4R and Allura red. The practical application of this new sensing platform was demonstrated using drink samples, and the detected results consisted with the values that obtained by high-performance liquid chromatography. - Highlights: • PC samples with different morphology and electrochemical activities were prepared. • Highly sensitive electrochemical sensing platform was developed for food colourants. • The accuracy and practicability was testified to be good by HPLC.

  9. Optical chemical sensors for atmospheric pollutants based on nano porous materials: application to the formaldehyde and the other carbonyl compounds

    International Nuclear Information System (INIS)

    Paolacci, H.

    2006-12-01

    Formaldehyde, a well-identified indoor pollutant, was recently classified as carcinogenic. New regulations for the air quality are expected and therefore there is a need for low-cost sensors, sensitive and selective with a fast response time for the detection of formaldehyde at ppb level. In the present work, we had developed a chemical sensor based on nano-porous matrices doped with Fluoral-P and optical methods of detection. The nano-porous matrices, elaborated via the Sol-Gel process, display nano-pores whose cavity is tailored for the trapping of the targeted pollutant. They provide a first selectivity with the discrimination of the pollutants by their size. A second selectivity is obtained with a molecular probe, Fluoral-P, which reacts specifically with formaldehyde leading to the 3,5- di-acetyl-1,4-dihydro-lutidine (DDL). The kinetics of formation of DDL was studied as function of many parameters such as the concentration of Fluoral-P in the matrix, the pollutant content in gas mixture, the flow rate, the relative humidity of the gas mixtures and interference with other carbonylated compounds. The present chemical sensor can detect, via absorbance measurements, 2 ppb of formaldehyde within 30 min over a O to 60% relative humidity range. Moreover, to detect the total carbonylated compounds, we also explored the potentiality of a chemical sensor using, as a probe molecule, the 2'4-dinitro-phenyl-hydrazine which forms with these compounds the corresponding hydrazones derivatives. A patent was deposited for these two sensors. We have also developed a semi-miniaturized prototype for demonstration, using a flow cell, a miniaturized spectrophotometer, a light source and a lap-top. (author)

  10. Hydroquinone and quinone-grafted porous carbons for highly selective CO2 capture from flue gases and natural gas upgrading

    NARCIS (Netherlands)

    Wang, J.; Krishna, R.; Yang, J.; Deng, S.

    2015-01-01

    Hydroquinone and quinone functional groups were grafted onto a hierarchical porous carbon framework via the Friedel-Crafts reaction to develop more efficient adsorbents for the selective capture and removal of carbon dioxide from flue gases and natural gas. The oxygen-doped porous carbons were

  11. Hydrogen storage in single-wall carbon nano-tubes by means of laser excitation

    International Nuclear Information System (INIS)

    Oksengorn, B.

    2010-01-01

    A new mode for hydrogen adsorption and storage in single-wall carbon nano-tubes is used, on the basis of laser excitation. Remember that this method has been useful to obtain, in the case of the fullerene C 60 , many complex C 60 -atoms or C 60 -molecules, where atoms or molecular particles are trapped inside the C 60 -molecules. We think this method might be important to store many hydrogen molecules inside carbon nano-tubes. (author)

  12. Room-temperature aqueous plasma electrolyzing Al2O3 nano-coating on carbon fiber

    Science.gov (United States)

    Zhang, Yuping; Meng, Yang; Shen, Yonghua; Chen, Weiwei; Cheng, Huanwu; Wang, Lu

    2017-10-01

    A novel room-temperature aqueous plasma electrolysis technique has been developed in order to prepared Al2O3 nano-coating on each fiber within a carbon fiber bundle. The microstructure and formation mechanism of the Al2O3 nano-coating were systematically investigated. The oxidation resistance and tensile strength of the Al2O3-coated carbon fiber was measured at elevated temperatures. It showed that the dense Al2O3 nano-coating was relatively uniformly deposited with 80-120 nm in thickness. The Al2O3 nano-coating effectively protected the carbon fiber, evidenced by the slower oxidation rate and significant increase of the burn-out temperature from 800 °C to 950 °C. Although the bare carbon fiber remained ∼25 wt.% after oxidation at 700 °C for 20 min, a full destruction was observed, evidenced by the ∼0 GPa of the tensile strength, compared to ∼1.3 GPa of the Al2O3-coated carbon fiber due to the effective protection from the Al2O3 nano-coating. The formation mechanism of the Al2O3 nano-coating on carbon fiber was schematically established mainly based on the physic-chemical effect in the cathodic plasma arc zone.

  13. On the selection of optimized carbon nano tube synthesis method using analytic hierarchy process

    International Nuclear Information System (INIS)

    Besharati, M. K.; Afaghi Khatibi, A.; Akbari, M.

    2008-01-01

    Evidence from the early and late industrializes shows that technology, as the commercial application of scientific knowledge, has been a major driver of industrial and economic development. International technology transfer is now being recognized as having played an important role in the development of the most successful late industrializes of the second half of the twentieth Century. Our society stands to be significantly influenced by carbon nano tubes, shaped by nano tube applications in every aspect, just as silicon-based technology still shapes society today. Nano tubes can be formed in various structures using several different processing methods. In this paper, the synthesis methods used to produce nano tubes in industrial or laboratory scales are discussed and a comparison is made. A technical feasibility study is conducted by using the multi criteria decision-making model, namely Analytic Hierarchy Process. The article ends with a discussion of selecting the best method of Technology Transferring of Carbon Nano tubes to Iran

  14. Strongly coupled inorganic-nano-carbon hybrid materials for energy storage.

    Science.gov (United States)

    Wang, Hailiang; Dai, Hongjie

    2013-04-07

    The global shift of energy production from fossil fuels to renewable energy sources requires more efficient and reliable electrochemical energy storage devices. In particular, the development of electric or hydrogen powered vehicles calls for much-higher-performance batteries, supercapacitors and fuel cells than are currently available. In this review, we present an approach to synthesize electrochemical energy storage materials to form strongly coupled hybrids (SC-hybrids) of inorganic nanomaterials and novel graphitic nano-carbon materials such as carbon nanotubes and graphene, through nucleation and growth of nanoparticles at the functional groups of oxidized graphitic nano-carbon. We show that the inorganic-nano-carbon hybrid materials represent a new approach to synthesize electrode materials with higher electrochemical performance than traditional counterparts made by simple physical mixtures of electrochemically active inorganic particles and conducting carbon materials. The inorganic-nano-carbon hybrid materials are novel due to possible chemical bonding between inorganic nanoparticles and oxidized carbon, affording enhanced charge transport and increased rate capability of electrochemical materials without sacrificing specific capacity. Nano-carbon with various degrees of oxidation provides a novel substrate for nanoparticle nucleation and growth. The interactions between inorganic precursors and oxidized-carbon substrates provide a degree of control over the morphology, size and structure of the resulting inorganic nanoparticles. This paper reviews the recent development of inorganic-nano-carbon hybrid materials for electrochemical energy storage and conversion, including the preparation and functionalization of graphene sheets and carbon nanotubes to impart oxygen containing groups and defects, and methods of synthesis of nanoparticles of various morphologies on oxidized graphene and carbon nanotubes. We then review the applications of the SC

  15. Straightforward synthesis of a triazine-based porous carbon with high gas-uptake capacities

    DEFF Research Database (Denmark)

    Hu, Xinming; Chen, Qi; Zhao, Yan Chao

    2014-01-01

    A triazine-based porous carbon material (TPC-1) was prepared directly from a fluorinated aromatic nitrile in molten zinc chloride. Trimerization of the nitrile and subsequent defluorination carbonization of the polymeric network result in the formation of TPC-1. The defluorination process is reve...

  16. Porous carbon spheres via microwave-assisted synthesis for capacitive deionization

    International Nuclear Information System (INIS)

    Liu, Yong; Pan, Likun; Chen, Taiqiang; Xu, Xingtao; Lu, Ting; Sun, Zhuo; Chua, Daniel H.C.

    2015-01-01

    Highlights: • Porous carbon spheres were fabricated through a fast microwave-assisted approach. • The capacitive deionization performance of Porous carbon spheres was studied. • Porous carbon spheres exhibit a high NaCl removal with good regeneration ability. - Abstract: Porous carbon spheres (PCSs) were fabricated through a fast microwave-assisted approach using sucrose as the precursor in a microwave system and subsequent thermal treatment at 600, 800 and 1000 °C. The morphology, structure and electrochemical performance of the PCSs were characterized by scanning electron microscopy, Raman spectroscopy, nitrogen adsorption-desorption, cyclic voltammetry and electrochemical impedance spectroscopy. Their electrosorption performance in NaCl solution was studied and compared with activated carbon, carbon nanotubes, reduced graphene and carbon aerogels. The results show that due to their high specific surface area and low charge transfer resistance, PCSs treated at 1000 °C exhibit high electrosorption capacity of 5.81 m g g −1 when the initial solution concentration is 500 mg l −1 , which is higher than those of other carbon materials

  17. Pore size dependent molecular adsorption of cationic dye in biomass derived hierarchically porous carbon.

    Science.gov (United States)

    Chen, Long; Ji, Tuo; Mu, Liwen; Shi, Yijun; Wang, Huaiyuan; Zhu, Jiahua

    2017-07-01

    Hierarchically porous carbon adsorbents were successfully fabricated from different biomass resources (softwood, hardwood, bamboo and cotton) by a facile two-step process, i.e. carbonization in nitrogen and thermal oxidation in air. Without involving any toxic/corrosive chemicals, large surface area of up to 890 m 2 /g was achieved, which is comparable to commercial activated carbon. The porous carbons with various surface area and pore size were used as adsorbents to investigate the pore size dependent adsorption phenomenon. Based on the density functional theory, effective (E-SSA) and ineffective surface area (InE-SSA) was calculated considering the geometry of used probing adsorbate. It was demonstrated that the adsorption capacity strongly depends on E-SSA instead of total surface area. Moreover, a regression model was developed to quantify the adsorption capacities contributed from E-SSA and InE-SSA, respectively. The applicability of this model has been verified by satisfactory prediction results on porous carbons prepared in this work as well as commercial activated carbon. Revealing the pore size dependent adsorption behavior in these biomass derived porous carbon adsorbents will help to design more effective materials (either from biomass or other carbon resources) targeting to specific adsorption applications. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Porous core-shell carbon fibers derived from lignin and cellulose nanofibrils

    KAUST Repository

    Xu, Xuezhu

    2013-10-01

    This letter reports a method to produce lignin and cellulose nanofibrils (CNFs) based porous core-shell carbon fibers via co-electrospinning followed by controlled carbonization. Lignin formed the shell of the fiber while CNF network formed the porous core. Polyacrylonitrile (PAN) was added to the lignin solution to increase its electrospinability. CNFs were surface acetylated and dispersed in silicon oil to obtain a homogenous dispersion for electrospinning the porous core. Hollow lignin fibers were also electrospun using glycerin as the core material. FT-IR measurements confirmed the CNF acetylation. SEM micrographs showed the core-shell and hollow fiber nanostructures before and after carbonization. The novel carbon fibers synthesized in this study exhibited increased surface area and porosity that are promising for many advanced applications. © 2013 Elsevier B.V.

  19. Porous core-shell carbon fibers derived from lignin and cellulose nanofibrils

    KAUST Repository

    Xu, Xuezhu; Zhou, Jian; Jiang, Long; Lubineau, Gilles; Chen, Ye; Wu, Xiangfa; Piere, Robert

    2013-01-01

    This letter reports a method to produce lignin and cellulose nanofibrils (CNFs) based porous core-shell carbon fibers via co-electrospinning followed by controlled carbonization. Lignin formed the shell of the fiber while CNF network formed the porous core. Polyacrylonitrile (PAN) was added to the lignin solution to increase its electrospinability. CNFs were surface acetylated and dispersed in silicon oil to obtain a homogenous dispersion for electrospinning the porous core. Hollow lignin fibers were also electrospun using glycerin as the core material. FT-IR measurements confirmed the CNF acetylation. SEM micrographs showed the core-shell and hollow fiber nanostructures before and after carbonization. The novel carbon fibers synthesized in this study exhibited increased surface area and porosity that are promising for many advanced applications. © 2013 Elsevier B.V.

  20. Synthesis and Physical Characterization of Carbon Nano tubes Coated by Conducting Poly pyrrole

    International Nuclear Information System (INIS)

    Talib, A.B.Z.A.; Wan Mahmood Mat Yunus; Kasar Behzad; Nayereh Soltani

    2011-01-01

    This study describes the preparation of poly pyrrole multi walled carbon nano tube (PPy/ MWNT) composites by in situ chemical oxidative polymerization. Various ratios of functionalized MWNTs are dispersed in the water, and PPy are then synthesized via in-situ chemical oxidative polymerization on the surface of the carbon nano tubes. The morphology of the resulting complex nano tubes (MWNT-PPY) was characterized by scanning electron microscopy (SEM). The conductivity of each composite showed a maximum in the temperature scale of 120- 160 degree Celsius and then decreased dramatically with the increase of temperature. (author)

  1. Fabrication and characterization of drug-loaded nano-hydroxyapatite/polyamide 66 scaffolds modified with carbon nanotubes and silk fibroin

    Directory of Open Access Journals (Sweden)

    Yao MZ

    2016-11-01

    Full Text Available Meng-Zhu Yao,1 Ming-Yi Huang-Fu,1 Hui-Na Liu,1 Xia-Rong Wang,1 Xiaoxia Sheng,2 Jian-Qing Gao1 1Institute of Pharmaceutics, College of Pharmaceutical Sciences, Zhejiang University, 2Hangzhou SoliPharma Co., Ltd, Hangzhou, Zhejiang, People’s Republic of China Abstract: Nano-hydroxyapatite/polyamide 66 (nHA/PA66 porous scaffolds were fabricated by a phase inversion method. Carbon nanotubes (CNTs and silk fibroin (SF were used to modify the surface of the nHA/PA66 scaffolds by freeze-drying and cross-linking. Dexamethasone was absorbed to the CNTs to promote the osteogenic differentiation of bone mesenchymal stem cells (BMSCs. The cell viability of BMSCs was investigated by changing the concentration of the CNT dispersion, and the most biocompatible scaffold was selected. In addition, the morphology and mechanical property of the scaffolds were investigated. The results showed that the nHA/PA66 scaffolds modified with CNTs and SF met the requirements of bone tissue engineering scaffolds. The dexamethasone-loaded CNT/SF-nHA/PA66 composite scaffold promoted the osteogenic differentiation of BMSCs, and the drug-loaded scaffolds are expected to function as effective bone tissue engineering scaffolds. Keywords: BMSCs, tissue engineering, porous scaffold, carbon nanotubes, silk fibroin, surface modification, dexamethasone

  2. Oxygen- and Nitrogen-Enriched 3D Porous Carbon for Supercapacitors of High Volumetric Capacity.

    Science.gov (United States)

    Li, Jia; Liu, Kang; Gao, Xiang; Yao, Bin; Huo, Kaifu; Cheng, Yongliang; Cheng, Xiaofeng; Chen, Dongchang; Wang, Bo; Sun, Wanmei; Ding, Dong; Liu, Meilin; Huang, Liang

    2015-11-11

    Efficient utilization and broader commercialization of alternative energies (e.g., solar, wind, and geothermal) hinges on the performance and cost of energy storage and conversion systems. For now and in the foreseeable future, the combination of rechargeable batteries and electrochemical capacitors remains the most promising option for many energy storage applications. Porous carbonaceous materials have been widely used as an electrode for batteries and supercapacitors. To date, however, the highest specific capacitance of an electrochemical double layer capacitor is only ∼200 F/g, although a wide variety of synthetic approaches have been explored in creating optimized porous structures. Here, we report our findings in the synthesis of porous carbon through a simple, one-step process: direct carbonization of kelp in an NH3 atmosphere at 700 °C. The resulting oxygen- and nitrogen-enriched carbon has a three-dimensional structure with specific surface area greater than 1000 m(2)/g. When evaluated as an electrode for electrochemical double layer capacitors, the porous carbon structure demonstrated excellent volumetric capacitance (>360 F/cm(3)) with excellent cycling stability. This simple approach to low-cost carbonaceous materials with unique architecture and functionality could be a promising alternative to fabrication of porous carbon structures for many practical applications, including batteries and fuel cells.

  3. Effects of nano calcium carbonate and nano calcium citrate on toxicity in ICR mice and on bone mineral density in an ovariectomized mice model

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Sherry; Chen, Jin Ching; Hsu, Chin Wei; Chang, Walter H, E-mail: whchang@cycu.edu.t [Center for Nano Bioengineering, Chung Yuan Christian University, Chung Li 32023, Taiwan (China); Department of Biomedical Engineering, Chung Yuan Christian University, Chung Li 32023, Taiwan (China)

    2009-09-16

    Taking calcium supplements can reduce the risk of developing osteoporosis, but they are not readily absorbed in the gastrointestinal tract. Nanotechnology is expected to resolve this problem. In the present study, we examined whether the bioavailability of calcium carbonate and calcium citrate can be improved by reducing the particle size. The morphology of nano calcium carbonate and nano calcium citrate was characterized by dynamic laser-light scattering (DLS), field-emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). The measurements obtained from DLS, FE-SEM and TEM were comparable. Acute and sub-chronic toxicity tests were performed to establish the safety of these products after oral administration. The no-observed-adverse-effect levels of nano calcium carbonate and nano calcium citrate were 1.3 and 2.3 g kg{sup -1} body weight, respectively. The results of our in vivo studies indicate that administering nano calcium carbonate and nano calcium citrate can enhance the serum calcium concentration and maintain the whole-body bone mineral density in ovariectomized mice. These data suggest that nano calcium carbonate and nano calcium citrate are more bioavailable than micro calcium carbonate and micro calcium citrate, respectively.

  4. Hierarchical porous carbon aerogel derived from bagasse for high performance supercapacitor electrode.

    Science.gov (United States)

    Hao, Pin; Zhao, Zhenhuan; Tian, Jian; Li, Haidong; Sang, Yuanhua; Yu, Guangwei; Cai, Huaqiang; Liu, Hong; Wong, C P; Umar, Ahmad

    2014-10-21

    Renewable, cost-effective and eco-friendly electrode materials have attracted much attention in the energy conversion and storage fields. Bagasse, the waste product from sugarcane that mainly contains cellulose derivatives, can be a promising candidate to manufacture supercapacitor electrode materials. This study demonstrates the fabrication and characterization of highly porous carbon aerogels by using bagasse as a raw material. Macro and mesoporous carbon was first prepared by carbonizing the freeze-dried bagasse aerogel; consequently, microporous structure was created on the walls of the mesoporous carbon by chemical activation. Interestingly, it was observed that the specific surface area, the pore size and distribution of the hierarchical porous carbon were affected by the activation temperature. In order to evaluate the ability of the hierarchical porous carbon towards the supercapacitor electrode performance, solid state symmetric supercapacitors were assembled, and a comparable high specific capacitance of 142.1 F g(-1) at a discharge current density of 0.5 A g(-1) was demonstrated. The fabricated solid state supercapacitor displayed excellent capacitance retention of 93.9% over 5000 cycles. The high energy storage ability of the hierarchical porous carbon was attributed to the specially designed pore structures, i.e., co-existence of the micropores and mesopores. This research has demonstrated that utilization of sustainable biopolymers as the raw materials for high performance supercapacitor electrode materials is an effective way to fabricate low-cost energy storage devices.

  5. Preliminary Study of Fermented Tapioca for Synthesis of Carbon Nano tubes

    International Nuclear Information System (INIS)

    Nurulhuda Ismail; Ying, P.Y.

    2011-01-01

    Carbon nano tubes had been produced by various precursor such as gas (methane, carbon dioxide), oil (camphor oil, olive oil, and cooking oil) and alcohol. Different methods used for carbon nano tubes synthesis like arc discharge method, laser ablation method and chemical vapour deposition method. In this experiment, thermal chemical vapour deposition method was selected for carbon nano tubes synthesis. Starting material of fermented tapioca was used as carbon source for the process. Argon gas flow were controlled at around 10-15 bubbles per minute and deposition time around 20 to 30 minute. Others parameters such as temperature of furnace 1 and 2, amount of inoculum and catalyst have been studied. The asThermogravimetri (TGA) was used to determine the volatile temperature of the mixing catalyst and fermented tapioca extract. The grown carbon nano tubes morphology was characterized through Raman spectroscopy, scanning and Field Emission Scanning Electron Microscopy (FESEM) techniques. The surface morphology and uniformity of carbon nano tubes are reliant to parameters used. (author)

  6. Preparation of porous carbon nanofibers derived from PBI/PLLA for supercapacitor electrodes.

    Science.gov (United States)

    Jung, Kyung-Hye; Ferraris, John P

    2016-10-21

    Porous carbon nanofibers were prepared by electrospinning blend solutions of polybenzimidazole/poly-L-lactic acid (PBI/PLLA) and carbonization. During thermal treatment, PLLA was decomposed, resulting in the creation of pores in the carbon nanofibers. From SEM images, it is shown that carbon nanofibers had diameters in the range of 100-200 nm. The conversion of PBI to carbon was confirmed by Raman spectroscopy, and the surface area and pore volume of carbon nanofibers were determined using nitrogen adsorption/desorption analyses. To investigate electrochemical performances, coin-type cells were assembled using free-standing carbon nanofiber electrodes and ionic liquid electrolyte. cyclic voltammetry studies show that the PBI/PLLA-derived porous carbon nanofiber electrodes have higher capacitance due to lower electrochemical impedance compared to carbon nanofiber electrode from PBI only. These porous carbon nanofibers were activated using ammonia for further porosity improvement and annealed to remove the surface functional groups to better match the polarity of electrode and electrolyte. Ragone plots, correlating energy density with power density calculated from galvanostatic charge-discharge curves, reveal that activation/annealing further improves energy and power densities.

  7. Nano carbon supported platinum catalyst interaction behavior with perfluorosulfonic acid ionomer and their interface structures

    DEFF Research Database (Denmark)

    Andersen, Shuang Ma

    2016-01-01

    behavior of Nafion ionomer on platinized carbon nano fibers (CNFs), carbon nano tubes (CNTs) and amorphous carbon (Vulcan). The interaction is affected by the catalyst surface oxygen groups as well as porosity. Comparisons between the carbon supports and platinized equivalents are carried out. It reveals......The interaction between perfluorosulfonic acid ionomer and supported platinum catalyst is essential. It directly influences platinum accessibility, stability of carbon support and platinum, proton conductivity and electron conductivity in an electrode. In this study, we compare the adsorption...... that the platinization step modifies the surface nature of the carbon supports in terms of specific surface area, crystallinity and especially porosity; therefore, ionomer adsorption over carbon is not always representative for the ionomer adsorption over carbon supported catalyst, though indicative. Moreover...

  8. Gas anti-solvent precipitation assisted salt leaching for generation of micro- and nano-porous wall in bio-polymeric 3D scaffolds.

    Science.gov (United States)

    Flaibani, Marina; Elvassore, Nicola

    2012-08-01

    The mass transport through biocompatible and biodegradable polymeric 3D porous scaffolds may be depleted by non-porous impermeable internal walls. As consequence the concentration of metabolites and growth factors within the scaffold may be heterogeneous leading to different cell fate depending on spatial cell location, and in some cases it may compromise cell survival. In this work, we fabricated polymeric scaffolds with micro- and nano-scale porosity by developing a new technique that couples two conventional scaffold production methods: solvent casting-salt leaching and gas antisolvent precipitation. 10-15 w/w solutions of a hyaluronic benzyl esters (HYAFF11) and poly-(lactic acid) (PLA) were used to fill packed beds of 0.177-0.425 mm NaCl crystals. The polymer precipitation in micro and nano-porous structures between the salt crystals was induced by high-pressure gas, then its flushing extracted the residual solvent. The salt was removed by water-wash. Morphological analysis by scanning electron microscopy showed a uniform porosity (~70%) and a high interconnectivity between porous. The polymeric walls were porous themselves counting for 30% of the total porosity. This wall porosity did not lead to a remarkable change in compressive modulus, deformation, and rupture pressure. Scaffold biocompatibility was tested with murine muscle cell line C2C12 for 4 and 7 days. Viability analysis and histology showed that micro- and nano-porous scaffolds are biocompatible and suitable for 3D cell culture promoting cell adhesion on the polymeric wall and allowing their proliferation in layers. Micro- and nano-scale porosities enhance cell migration and growth in the inner part of the scaffold. Copyright © 2012 Elsevier B.V. All rights reserved.

  9. Converting biowaste corncob residue into high value added porous carbon for supercapacitor electrodes.

    Science.gov (United States)

    Qu, Wen-Hui; Xu, Yuan-Yuan; Lu, An-Hui; Zhang, Xiang-Qian; Li, Wen-Cui

    2015-08-01

    In this report, corncob residue, the main by-product in the furfural industry, is used as a precursor to prepare porous carbon by a simple and direct thermal treatment: one-step activation without pre-carbonization. As a consequence, the corncob residue derived porous carbon achieves a high surface area of 1210 m(2) g(-1) after ash-removal. The carbon material has the advantages of low cost and low environmental impact, with a superior electrochemical performance compared to those polymer-based synthetic carbons as electrode material for a supercapacitor. The carbon electrode exhibits a high capacitance of 314 F g(-1) in 6M KOH electrolyte. The corresponding sample also shows a superb cycling stability. Almost no capacitance decay was observed after 100,000 cycles. The excellent electrochemical performance is due to the combination of a high specific surface area with a fraction of mesopores and highly stable structure. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. Empirical Correlation of the Morphology of Coiled Carbon Nano tubes with Their Response to Axial Compression

    International Nuclear Information System (INIS)

    Barber, J.R.; Boyles, J.S.; Bottomley, L.A.; Ferri, A.A.

    2014-01-01

    The mechanical response of thirteen different helical multi-walled carbon nano coils to axial compression is reported. Each nano coil was attached to the apex of a cantilever probe tip; its dimensions and orientation relative to the tip apex were determined with scanning electron microscopy. The atomic force microscope was employed to apply a cyclic axial load on the nano coil. Its mechanical response was determined by simultaneous collection of the thermal resonance frequency, displacement, and oscillation amplitude of the cantilever-nano tube system in real time. Depending upon compression parameters, each coil underwent buckling, bending, and slip-stick motion. Characteristic features in the thermal resonance spectrum and in the force and oscillation amplitude curves for each of these responses to induced stress are presented. Following compression studies, the structure and morphology of each nano coil were determined by transmission electron microscopy. The compression stiffness of each nano coil was estimated from the resonant frequency of the cantilever at the point of contact with the substrate surface. From this value, the elastic modulus of the nano coil was computed and correlated with the coiled carbon nano tube’s morphology.

  11. Facile preparation of hierarchically porous carbon using diatomite as both template and catalyst and methylene blue adsorption of carbon products.

    Science.gov (United States)

    Liu, Dong; Yuan, Peng; Tan, Daoyong; Liu, Hongmei; Wang, Tong; Fan, Mingde; Zhu, Jianxi; He, Hongping

    2012-12-15

    Hierarchically porous carbons were prepared using a facile preparation method in which diatomite was utilized as both template and catalyst. The porous structures of the carbon products and their formation mechanisms were investigated. The macroporosity and microporosity of the diatomite-templated carbons were derived from replication of diatom shell and structure-reconfiguration of the carbon film, respectively. The macroporosity of carbons was strongly dependent on the original morphology of the diatomite template. The macroporous structure composed of carbon plates connected by the pillar- and tube-like macropores resulted from the replication of the central and edge pores of the diatom shells with disk-shaped morphology, respectively. And another macroporous carbon tubes were also replicated from canoe-shaped diatom shells. The acidity of diatomite dramatically affected the porosity of the carbons, more acid sites of diatomite template resulted in higher surface area and pore volume of the carbon products. The diatomite-templated carbons exhibited higher adsorption capacity for methylene blue than the commercial activated carbon (CAC), although the specific surface area was much smaller than that of CAC, due to the hierarchical porosity of diatomite-templated carbons. And the carbons were readily reclaimed and regenerated. Copyright © 2012 Elsevier Inc. All rights reserved.

  12. Drug loading into porous calcium carbonate microparticles by solvent evaporation.

    Science.gov (United States)

    Preisig, Daniel; Haid, David; Varum, Felipe J O; Bravo, Roberto; Alles, Rainer; Huwyler, Jörg; Puchkov, Maxim

    2014-08-01

    Drug loading into porous carriers may improve drug release of poorly water-soluble drugs. However, the widely used impregnation method based on adsorption lacks reproducibility and efficiency for certain compounds. The aim of this study was to evaluate a drug-loading method based on solvent evaporation and crystallization, and to investigate the underlying drug-loading mechanisms. Functionalized calcium carbonate (FCC) microparticles and four drugs with different solubility and permeability properties were selected as model substances to investigate drug loading. Ibuprofen, nifedipine, losartan potassium, and metronidazole benzoate were dissolved in acetone or methanol. After dispersion of FCC, the solvent was removed under reduced pressure. For each model drug, a series of drug loads were produced ranging from 25% to 50% (w/w) in steps of 5% (w/w). Loading efficiency was qualitatively analyzed by scanning electron microscopy (SEM) using the presence of agglomerates and drug crystals as indicators of poor loading efficiency. The particles were further characterized by mercury porosimetry, specific surface area measurements, differential scanning calorimetry, and USP2 dissolution. Drug concentration was determined by HPLC. FCC-drug mixtures containing equivalent drug fractions but without specific loading strategy served as reference samples. SEM analysis revealed high efficiency of pore filling up to a drug load of 40% (w/w). Above this, agglomerates and separate crystals were significantly increased, indicating that the maximum capacity of drug loading was reached. Intraparticle porosity and specific surface area were decreased after drug loading because of pore filling and crystallization on the pore surface. HPLC quantification of drugs taken up by FCC showed only minor drug loss. Dissolution rate of FCC loaded with metronidazole benzoate and nifedipine was faster than the corresponding FCC-drug mixtures, mainly due to surface enlargement, because only small

  13. Generalized Lagrangian Jacobi Gauss collocation method for solving unsteady isothermal gas through a micro-nano porous medium

    Science.gov (United States)

    Parand, Kourosh; Latifi, Sobhan; Delkhosh, Mehdi; Moayeri, Mohammad M.

    2018-01-01

    In the present paper, a new method based on the Generalized Lagrangian Jacobi Gauss (GLJG) collocation method is proposed. The nonlinear Kidder equation, which explains unsteady isothermal gas through a micro-nano porous medium, is a second-order two-point boundary value ordinary differential equation on the unbounded interval [0, ∞). Firstly, using the quasilinearization method, the equation is converted to a sequence of linear ordinary differential equations. Then, by using the GLJG collocation method, the problem is reduced to solving a system of algebraic equations. It must be mentioned that this equation is solved without domain truncation and variable changing. A comparison with some numerical solutions made and the obtained results indicate that the presented solution is highly accurate. The important value of the initial slope, y'(0), is obtained as -1.191790649719421734122828603800159364 for η = 0.5. Comparing to the best result obtained so far, it is accurate up to 36 decimal places.

  14. Study the effect of striping in two-step anodizing process on pore arrangement of nano-porous alumina

    International Nuclear Information System (INIS)

    Rahimi, M.H.; Saramad, S.; Tabaian, S.H.; Marashi, S.P.; Zolfaghari, A.; Mohammadalinezhad, M.

    2009-01-01

    Two-step anodic oxidation of aluminum is generally employed to produce the ordered porous anodized alumina (PAA). Dissolving away (striping) the oxide film after the first anodizing step plays a key role in the final arrangement of nano-pores. In this work, different striping durations between 1 and 6 h were applied to the sample that was initially anodized at a constant voltage of 40 V at 17 deg. C for 15 h. The striping duration of 3 h was realized as the optimum time for achieving the best ordering degree for the pores. Scanning electron microscopy (SEM) was used during and at the end of the process to examine the cross section and finishing surface of the specimens. Linear-angular fast Fourier transform (LA-FFT), an in-house technique based on MATLAB software, was employed to assess the ordering degree of the anodized samples.

  15. Study the effect of striping in two-step anodizing process on pore arrangement of nano-porous alumina

    Energy Technology Data Exchange (ETDEWEB)

    Rahimi, M.H. [Department of Mining and Metallurgical Engineering, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of); Saramad, S., E-mail: ssaramad@aut.ac.ir [Department of Physics, Amirkabir University of Technology, Hafez Avenue, Tehran (Iran, Islamic Republic of); Tabaian, S.H.; Marashi, S.P. [Department of Mining and Metallurgical Engineering, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of); Zolfaghari, A. [Chemistry and Chemical Engineering Research Centre of Iran, Tehran (Iran, Islamic Republic of); Mohammadalinezhad, M. [Department of Mining and Metallurgical Engineering, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of)

    2009-10-15

    Two-step anodic oxidation of aluminum is generally employed to produce the ordered porous anodized alumina (PAA). Dissolving away (striping) the oxide film after the first anodizing step plays a key role in the final arrangement of nano-pores. In this work, different striping durations between 1 and 6 h were applied to the sample that was initially anodized at a constant voltage of 40 V at 17 deg. C for 15 h. The striping duration of 3 h was realized as the optimum time for achieving the best ordering degree for the pores. Scanning electron microscopy (SEM) was used during and at the end of the process to examine the cross section and finishing surface of the specimens. Linear-angular fast Fourier transform (LA-FFT), an in-house technique based on MATLAB software, was employed to assess the ordering degree of the anodized samples.

  16. Study the effect of striping in two-step anodizing process on pore arrangement of nano-porous alumina

    Science.gov (United States)

    Rahimi, M. H.; Saramad, S.; Tabaian, S. H.; Marashi, S. P.; Zolfaghari, A.; Mohammadalinezhad, M.

    2009-10-01

    Two-step anodic oxidation of aluminum is generally employed to produce the ordered porous anodized alumina (PAA). Dissolving away (striping) the oxide film after the first anodizing step plays a key role in the final arrangement of nano-pores. In this work, different striping durations between 1 and 6 h were applied to the sample that was initially anodized at a constant voltage of 40 V at 17 °C for 15 h. The striping duration of 3 h was realized as the optimum time for achieving the best ordering degree for the pores. Scanning electron microscopy (SEM) was used during and at the end of the process to examine the cross section and finishing surface of the specimens. Linear-angular fast Fourier transform (LA-FFT), an in-house technique based on MATLAB software, was employed to assess the ordering degree of the anodized samples.

  17. Fabrication of Pd Micro-Membrane Supported on Nano-Porous Anodized Aluminum Oxide for Hydrogen Separation.

    Science.gov (United States)

    Kim, Taegyu

    2015-08-01

    In the present study, nano-porous anodized aluminum oxide (AAO) was used as a support of the Pd membrane. The AAO fabrication process consists of an electrochemical polishing, first/second anodizing, barrier layer dissolving and pores widening. The Pd membrane was deposited on the AAO support using an electroless plating with ethylenediaminetetraacetic acid (EDTA) as a plating agent. The AAO had the regular pore structure with the maximum pore diameter of ~100 nm so it had a large opening area but a small free standing area. The 2 µm-thick Pd layer was obtained by the electroless plating for 3 hours. The Pd layer thickness increased with increasing the plating time. However, the thickness was limited to ~5 µm in maximum. The H2 permeation flux was 0.454 mol/m2-s when the pressure difference of 66.36 kPa0.5 was applied at the Pd membrane under 400 °C.

  18. Synthesis of Na-A and/or Na-X zeolite/porous carbon composites from carbonized rice husk

    International Nuclear Information System (INIS)

    Katsuki, Hiroaki; Komarneni, Sridhar

    2009-01-01

    Na-A and/or Na-X zeolite/porous carbon composites were prepared under hydrothermal conditions by NaOH dissolution of silica first from carbonized rice husk followed by addition of NaAlO 2 and in situ crystallization of zeolites i.e., using a two-step process. When a one-step process was used, both Na-A and Na-X zeolites crystallized on the surface of carbon. Na-A or Na-X zeolite crystals were prepared on the porous carbonized rice husk at 90 deg. C for 2-6 h by changing the SiO 2 /Al 2 O 3 , H 2 O/Na 2 O and Na 2 O/SiO 2 molar ratios of precursors in the two-step process. The surface area and NH 4 + -cation exchange capacity (CEC) of Na-A zeolite/porous carbon were found to be 171 m 2 /g and 506 meq/100 g, respectively, while those of Na-X zeolite/porous carbon composites were 676 m 2 /g and 317 meq/100 g, respectively. Na-A and Na-X zeolites are well-known microporous and hydrophilic materials while carbonized rice husk was found to be mesoporous (pores of ∼3.9 nm) and hydrophobic. These hybrid microporous-mesoporous and hydrophilic-hydrophobic composites are expected to be useful for decontamination of metal cations as well as organic contaminants simultaneously. - Graphical Abstract: Novel Na-X zeolite/porous carbon composite.

  19. Citrus pectin derived porous carbons as a superior adsorbent toward removal of methylene blue

    International Nuclear Information System (INIS)

    Zhang, Wenlin; Zhang, Lian Ying; Zhao, Xi Juan; Zhou, Zhiqin

    2016-01-01

    An adsorbent, citrus pectin derived porous carbons with ultra-high adsorption capacity, rapid adsorption rate and good reusability toward removal of methylene blue, was synthesized by a facile zinc chloride activation approach in this study. The materials hold a great potential for treatment of dye wastewater. - Graphical abstract: Citrus pectin derived porous carbons with ultra-high adsorption capacity, rapid adsorption rate and good reusability toward methylene blue removal. - Highlights: • Citrus pectin derived porous carbons (CPPCs) were synthesized a facile zinc chloride activation approach. • CPPCs had abundant macro/meso/micropores for trapping MB molecules. • CPPCs exhibited ultrahigh adsorption capacity, rapid adsorption rate and good reusability toward removal of MB.

  20. Hierarchically Porous Carbon Materials for CO 2 Capture: The Role of Pore Structure

    Energy Technology Data Exchange (ETDEWEB)

    Estevez, Luis [Pacific Northwest National Laboratory, 902 Battelle Boulevard, Richland, Washington 99352, United States; Barpaga, Dushyant [Pacific Northwest National Laboratory, 902 Battelle Boulevard, Richland, Washington 99352, United States; Zheng, Jian [Pacific Northwest National Laboratory, 902 Battelle Boulevard, Richland, Washington 99352, United States; Sabale, Sandip [Pacific Northwest National Laboratory, 902 Battelle Boulevard, Richland, Washington 99352, United States; Patel, Rajankumar L. [Pacific Northwest National Laboratory, 902 Battelle Boulevard, Richland, Washington 99352, United States; Zhang, Ji-Guang [Pacific Northwest National Laboratory, 902 Battelle Boulevard, Richland, Washington 99352, United States; McGrail, B. Peter [Pacific Northwest National Laboratory, 902 Battelle Boulevard, Richland, Washington 99352, United States; Motkuri, Radha Kishan [Pacific Northwest National Laboratory, 902 Battelle Boulevard, Richland, Washington 99352, United States

    2018-01-17

    With advances in porous carbon synthesis techniques, hierarchically porous carbon (HPC) materials are being utilized as relatively new porous carbon sorbents for CO2 capture applications. These HPC materials were used as a platform to prepare samples with differing textural properties and morphologies to elucidate structure-property relationships. It was found that high microporous content, rather than overall surface area was of primary importance for predicting good CO2 capture performance. Two HPC materials were analyzed, each with near identical high surface area (~2700 m2/g) and colossally high pore volume (~10 cm3/g), but with different microporous content and pore size distributions, which led to dramatically different CO2 capture performance. Overall, large pore volumes obtained from distinct mesopores were found to significantly impact adsorption performance. From these results, an optimized HPC material was synthesized that achieved a high CO2 capacity of ~3.7 mmol/g at 25°C and 1 bar.

  1. Citrus pectin derived porous carbons as a superior adsorbent toward removal of methylene blue

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Wenlin [College of Horticulture and landscape Architecture, Southwest University, Chongqing 400716 (China); Zhang, Lian Ying [Institute for Clean Energy & Advanced Materials, Southwest University, Chongqing 400715 (China); Zhao, Xi Juan [College of Horticulture and landscape Architecture, Southwest University, Chongqing 400716 (China); Key Laboratory of Horticulture Science for Southern Mountainous Regions, Ministry of Education, Chongqing 400715 (China); Zhou, Zhiqin, E-mail: zhouzhiqin@swu.edu.cn [College of Horticulture and landscape Architecture, Southwest University, Chongqing 400716 (China); Key Laboratory of Horticulture Science for Southern Mountainous Regions, Ministry of Education, Chongqing 400715 (China)

    2016-11-15

    An adsorbent, citrus pectin derived porous carbons with ultra-high adsorption capacity, rapid adsorption rate and good reusability toward removal of methylene blue, was synthesized by a facile zinc chloride activation approach in this study. The materials hold a great potential for treatment of dye wastewater. - Graphical abstract: Citrus pectin derived porous carbons with ultra-high adsorption capacity, rapid adsorption rate and good reusability toward methylene blue removal. - Highlights: • Citrus pectin derived porous carbons (CPPCs) were synthesized a facile zinc chloride activation approach. • CPPCs had abundant macro/meso/micropores for trapping MB molecules. • CPPCs exhibited ultrahigh adsorption capacity, rapid adsorption rate and good reusability toward removal of MB.

  2. On the use of mesophase pitch for the preparation of hierarchical porous carbon monoliths by nanocasting

    Directory of Open Access Journals (Sweden)

    Philipp Adelhelm, Karin Cabrera and Bernd M Smarsly

    2012-01-01

    Full Text Available A detailed study is given on the synthesis of a hierarchical porous carbon, possessing both meso- and macropores, using a mesophase pitch (MP as the carbon precursor. This carbon material is prepared by the nanocasting approach involving the replication of a porous silica monolith (hard templating. While this carbon material has already been tested in energy storage applications, various detailed aspects of its formation and structure are addressed in this study. Scanning electron microscopy (SEM, Hg porosimetry and N2 physisorption are used to characterize the morphology and porosity of the carbon replica. A novel approach for the detailed analysis of wide-angle x-ray scattering (WAXS from non-graphitic carbons is applied to quantitatively compare the graphene microstructures of carbons prepared using MP and furfuryl alcohol (FA. This WAXS analysis underlines the importance of the carbon precursor in the synthesis of templated porous carbon materials via the nanocasting route. Our study demonstrates that a mesophase pitch is a superior precursor whenever a high-purity, low-micropore-content and well-developed graphene structure is desired.

  3. The effects of carbon nano filaments (CNT and CNF) doping on high temperature superconductors Y-123

    International Nuclear Information System (INIS)

    Dadras, S.; Daadmehr, V.

    2007-01-01

    Full text: This paper is based on the effects of carbon nano filaments (carbon nano tubes and carbon nano fibers) doping on Y-123 studies. We synthesized Y-123 with different contents of CNT and CNF doping. The samples were prepared from powders of Y 2 O 3 , BaCO 3 and Cu O by the solid state reaction. After calcination in air, we mixed Y-123 powder with different percentage of carbon nano filaments weight, produced by the CVD method. For obtaining more homogenous mixing, we have suspended it in an organic solvent with an ultrasonic mixer to prevent agglomeration of CNT. The CNT-Y-123 powder was dried afterwards, and pressed as pellet samples, in about 1mm thick, 10mm diameter, and 1gr weight, and sintered in oxygen atmosphere. We tried to find the transport effects on CNT and CNF doping in 123 systems. The strong coupling between grains in CNT doped samples caused the flow of inter-granular currents. Therefore the presence of CNT in high temperature superconductor samples increases the critical current density. Among various carbon precursors, carbon nano tubes (CNT) are very interesting because of their nano meter diameter which may make them as effective pinning centers, compared to the ordinary carbon. The carbon nano tubes are functioning like columnar defects produced by heavy-ion irradiation. Nano phase particles or aggregates embodied in the superconductor matrix can pin the flux lines effectively and enhance the intra-grain transport critical current density in high applied magnetic fields. Nano phase size particles in the size range of about 5-10 nm can be used as flux pinning centers for low field applications. The effects of carbon and carbon dioxide in Y-123 were studied by several groups, but none of them argued the effects of carbon nano tubes doping on Y-123. Uno et al. found that Jc was related to the carbon concentration, but they showed that Tc value and other physical properties did not change. In carbon doped Y-123 samples, Tc decreases with

  4. Gas anti-solvent precipitation assisted salt leaching for generation of micro- and nano-porous wall in bio-polymeric 3D scaffolds

    Energy Technology Data Exchange (ETDEWEB)

    Flaibani, Marina; Elvassore, Nicola, E-mail: nicola.elvassore@unipd.it

    2012-08-01

    The mass transport through biocompatible and biodegradable polymeric 3D porous scaffolds may be depleted by non-porous impermeable internal walls. As consequence the concentration of metabolites and growth factors within the scaffold may be heterogeneous leading to different cell fate depending on spatial cell location, and in some cases it may compromise cell survival. In this work, we fabricated polymeric scaffolds with micro- and nano-scale porosity by developing a new technique that couples two conventional scaffold production methods: solvent casting-salt leaching and gas antisolvent precipitation. 10-15 w/w solutions of a hyaluronic benzyl esters (HYAFF11) and poly-(lactic acid) (PLA) were used to fill packed beds of 0.177-0.425 mm NaCl crystals. The polymer precipitation in micro and nano-porous structures between the salt crystals was induced by high-pressure gas, then its flushing extracted the residual solvent. The salt was removed by water-wash. Morphological analysis by scanning electron microscopy showed a uniform porosity ({approx} 70%) and a high interconnectivity between porous. The polymeric walls were porous themselves counting for 30% of the total porosity. This wall porosity did not lead to a remarkable change in compressive modulus, deformation, and rupture pressure. Scaffold biocompatibility was tested with murine muscle cell line C2C12 for 4 and 7 days. Viability analysis and histology showed that micro- and nano-porous scaffolds are biocompatible and suitable for 3D cell culture promoting cell adhesion on the polymeric wall and allowing their proliferation in layers. Micro- and nano-scale porosities enhance cell migration and growth in the inner part of the scaffold. - Highlights: Black-Right-Pointing-Pointer Gas anti-solvent precipitation and salt leaching for scaffold fabrication. Black-Right-Pointing-Pointer Hyaluronic benzyl esters (HYAFF11) and poly-(lactic acid) (PLA) sponges. Black-Right-Pointing-Pointer Gas anti-solvent precipitation

  5. Gas anti-solvent precipitation assisted salt leaching for generation of micro- and nano-porous wall in bio-polymeric 3D scaffolds

    International Nuclear Information System (INIS)

    Flaibani, Marina; Elvassore, Nicola

    2012-01-01

    The mass transport through biocompatible and biodegradable polymeric 3D porous scaffolds may be depleted by non-porous impermeable internal walls. As consequence the concentration of metabolites and growth factors within the scaffold may be heterogeneous leading to different cell fate depending on spatial cell location, and in some cases it may compromise cell survival. In this work, we fabricated polymeric scaffolds with micro- and nano-scale porosity by developing a new technique that couples two conventional scaffold production methods: solvent casting-salt leaching and gas antisolvent precipitation. 10–15 w/w solutions of a hyaluronic benzyl esters (HYAFF11) and poly-(lactic acid) (PLA) were used to fill packed beds of 0.177–0.425 mm NaCl crystals. The polymer precipitation in micro and nano-porous structures between the salt crystals was induced by high-pressure gas, then its flushing extracted the residual solvent. The salt was removed by water-wash. Morphological analysis by scanning electron microscopy showed a uniform porosity (∼ 70%) and a high interconnectivity between porous. The polymeric walls were porous themselves counting for 30% of the total porosity. This wall porosity did not lead to a remarkable change in compressive modulus, deformation, and rupture pressure. Scaffold biocompatibility was tested with murine muscle cell line C2C12 for 4 and 7 days. Viability analysis and histology showed that micro- and nano-porous scaffolds are biocompatible and suitable for 3D cell culture promoting cell adhesion on the polymeric wall and allowing their proliferation in layers. Micro- and nano-scale porosities enhance cell migration and growth in the inner part of the scaffold. - Highlights: ► Gas anti-solvent precipitation and salt leaching for scaffold fabrication. ► Hyaluronic benzyl esters (HYAFF11) and poly-(lactic acid) (PLA) sponges. ► Gas anti-solvent precipitation induces nano-porous structures. ► Scaffolds are biocompatible and

  6. Popcorn-Derived Porous Carbon Flakes with an Ultrahigh Specific Surface Area for Superior Performance Supercapacitors.

    Science.gov (United States)

    Hou, Jianhua; Jiang, Kun; Wei, Rui; Tahir, Muhammad; Wu, Xiaoge; Shen, Ming; Wang, Xiaozhi; Cao, Chuanbao

    2017-09-13

    Popcorn-derived porous carbon flakes have been successfully fabricated from the biomass of maize. Utilizing the "puffing effect", the nubby maize grain turned into materials with an interconnected honeycomb-like porous structure composed of carbon flakes. The following chemical activation method enabled the as-prepared products to possess optimized porous structures for electrochemical energy-storage devices, such as multilayer flake-like structures, ultrahigh specific surface area (S BET : 3301 m 2 g -1 ), and a high content of micropores (microporous surface area of 95%, especially the optimized sub-nanopores with the size of 0.69 nm) that can increase the specific capacitance. The as-obtained sample displayed excellent specific capacitance of 286 F g -1 at 90 A g -1 for supercapacitors. Moreover, the unique porous structure demonstrated an ideal way to improve the volumetric energy density performance. A high energy density of 103 Wh kg -1 or 53 Wh L -1 has been obtained in the case of ionic liquid electrolyte, which is the highest among reported biomass-derived carbon materials and will satisfy the urgent requirements of a primary power source for electric vehicles. This work may prove to be a fast, green, and large-scale synthesis route by using the large nubby granular materials to synthesize applicable porous carbons in energy-storage devices.

  7. Micropore engineering of carbonized porous aromatic framework (PAF-1) for supercapacitors application.

    Science.gov (United States)

    Li, Yanqiang; Roy, Soumyajit; Ben, Teng; Xu, Shixian; Qiu, Shilun

    2014-07-07

    Micropore engineering of porous carbons on the effect of capacitance was explored using a carbonized porous aromatic framework (PAF-1). The porous carbons obtained through different carbonization methods show different pore structures enabling us to do this. The capacitance was measured both in aqueous electrolyte and different organic electrolytes. The porous carbons prepared by KOH activation show both high microporous volume, which is beneficial for charge storage, and mesoporous volume, which is devoted to fast ion diffusion in the pores; properties which are highly desirable. It shows a capacitance as high as 280 F g(-1) and 203 F g(-1) at a current density of 1 A g(-1) in 6.0 M KOH and 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (EMImTFSI), respectively. We also demonstrate the effect of diffusion and that of geometric packing of the electrolyte ions in the pores, where a commensurate match of the electrolyte ions with the pores of carbonized materials control and influence significantly the capacitance of these materials.

  8. Heteroatom-doped porous carbon from methyl orange dye wastewater for oxygen reduction

    Directory of Open Access Journals (Sweden)

    Yiqing Wang

    2018-04-01

    Full Text Available Banana peel-derived porous carbon (BPPC was prepared from banana peel and used as an adsorbent for methyl orange (MO wastewater removal. BPPC-MO50 is a N,S-doped BPPC obtained via secondary carbonization. The BPPC-MO50 exhibited a high specific surface area of 1774.3 m2/g. Heteroatom-doped porous carbon (PC was successfully synthesized from the BPPC absorbed MO at high temperature and used for oxygen reduction. The BPPC-MO50 displayed the highest ORR onset potential among all carbon-based electrocatalysts, i.e., 0.93 V vs. reversible hydrogen electrode (RHE. This is the first report to describe porous carbon-activated materials from agriculture and forestry waste that is used for adsorption of dyes from wastewater via an enhanced heteroatom (N,S content. These results may contribute to the sustainable development of dye wastewater treatment by transforming saturated PC into an effective material and has potential applications in fuel cells or as energy sources. Keywords: Banana peel, Dye wastewater, Porous carbon, Heteroatom doping, Oxygen reduction reaction

  9. Facile preparation of nitrogen-doped hierarchical porous carbon with high performance in supercapacitors

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Kun [State Key Laboratory of Advanced Processing and Recycling of Non-ferrous Metals, Lanzhou University of Technology, Lanzhou 730050 (China); Kong, Ling-Bin, E-mail: konglb@lut.cn [State Key Laboratory of Advanced Processing and Recycling of Non-ferrous Metals, Lanzhou University of Technology, Lanzhou 730050 (China); School of Materials Science and Engineering, Lanzhou University of Technology, Lanzhou 730050 (China); Shen, Kui-Wen; Dai, Yan-Hua; Shi, Ming; Hu, Bing [State Key Laboratory of Advanced Processing and Recycling of Non-ferrous Metals, Lanzhou University of Technology, Lanzhou 730050 (China); Luo, Yong-Chun; Kang, Long [School of Materials Science and Engineering, Lanzhou University of Technology, Lanzhou 730050 (China)

    2016-02-28

    Graphical abstract: Preparing and activating process of nitrogen-doped hierarchical porous carbon (NHPC). - Highlights: • The well-defined PAN-b-PMMA copolymer was synthesized by atom transfer radical polymerization with narrow molecular weight distribution. • Nitrogen-doped hierarchical porous structure (NHPC) was prepared through a simple carbonization procedure of PAN-b-PMMA precursor. • NHPC possessed hierarchical porous structure with high BET surface area of 257 m{sup 2} g{sup −1} and DFT mesopore size of 14.61 nm. • Effects of activation conditions on supercapacitive behavior were systematically studied. - Abstract: The nitrogen-doped hierarchical porous carbon (NHPC) material was successfully prepared through a simple carbonization procedure of well-defined diblock copolymer precursor containing nitrogen-enriched carbon source, i.e., polyacrylonitrile (PAN), and asacrificial block, i.e., polymethylmethacrylate (PMMA). PAN-b-PMMA diblock copolymer was synthesized by atom transfer radical polymeriation (ATRP) with narrow molecular weight distribution. The as-obtained NHPC possessed nitrogen-doped hierarchical porous structure with high BET surface area of 257 m{sup 2} g{sup −1} and Nonlocal density functional theory (NLDFT) mesopore size of 14.61 nm. Surface activated nitrogen-doped hierarchical porous carbon (A-NHPC) materials were obtained by subsequent surface activation with HNO{sub 3} solution. The effects of activation conditions on supercapacitive behavior were systematically studied, a maximum specific capacitance of 314 F g{sup −1} at a current density of 0.5 A g{sup −1} was achieved in 2 M KOH aqueous electrolyte. Simultaneously, it exhibited excellent rate capability of 67.8% capacitance retention as the current density increased from 0.5 to 20 A g{sup −1} and superior cycling performance of 90% capacitance retention after 10,000 cycles at the current density of 2 A g{sup −1}.

  10. Facile preparation of nitrogen-doped hierarchical porous carbon with high performance in supercapacitors

    International Nuclear Information System (INIS)

    Yan, Kun; Kong, Ling-Bin; Shen, Kui-Wen; Dai, Yan-Hua; Shi, Ming; Hu, Bing; Luo, Yong-Chun; Kang, Long

    2016-01-01

    Graphical abstract: Preparing and activating process of nitrogen-doped hierarchical porous carbon (NHPC). - Highlights: • The well-defined PAN-b-PMMA copolymer was synthesized by atom transfer radical polymerization with narrow molecular weight distribution. • Nitrogen-doped hierarchical porous structure (NHPC) was prepared through a simple carbonization procedure of PAN-b-PMMA precursor. • NHPC possessed hierarchical porous structure with high BET surface area of 257 m"2 g"−"1 and DFT mesopore size of 14.61 nm. • Effects of activation conditions on supercapacitive behavior were systematically studied. - Abstract: The nitrogen-doped hierarchical porous carbon (NHPC) material was successfully prepared through a simple carbonization procedure of well-defined diblock copolymer precursor containing nitrogen-enriched carbon source, i.e., polyacrylonitrile (PAN), and asacrificial block, i.e., polymethylmethacrylate (PMMA). PAN-b-PMMA diblock copolymer was synthesized by atom transfer radical polymeriation (ATRP) with narrow molecular weight distribution. The as-obtained NHPC possessed nitrogen-doped hierarchical porous structure with high BET surface area of 257 m"2 g"−"1 and Nonlocal density functional theory (NLDFT) mesopore size of 14.61 nm. Surface activated nitrogen-doped hierarchical porous carbon (A-NHPC) materials were obtained by subsequent surface activation with HNO_3 solution. The effects of activation conditions on supercapacitive behavior were systematically studied, a maximum specific capacitance of 314 F g"−"1 at a current density of 0.5 A g"−"1 was achieved in 2 M KOH aqueous electrolyte. Simultaneously, it exhibited excellent rate capability of 67.8% capacitance retention as the current density increased from 0.5 to 20 A g"−"1 and superior cycling performance of 90% capacitance retention after 10,000 cycles at the current density of 2 A g"−"1.

  11. Decoration of carbon nano surfaces with hydrogen and hydrogen rich molecules

    International Nuclear Information System (INIS)

    Zöttl, S.

    2013-01-01

    The use of helium nano droplets as a matrix to investigate different atomic and molecular samples is a well established experimental technique. The unique properties of helium allow for different analytical methods and at the same time provide a stable ambient temperature. Cluster growth inside helium nano droplets can be accomplished by repeatedly doping the droplets with sample particles in a controlled environment. The experimental work represented in this thesis was performed using helium nano droplets to create clusters of fullerenes like C 60 and C 70 . The adsorption properties of these fullerene clusters regarding hydrogen and hydrogen rich molecules have been subject to investigation. The observed results suggest that curved carbon nano surfaces offer higher storage densities than planar graphite surfaces. The use of C 60 as a model carbon nano structure provides a well understood molecule for testing and evaluating computational methods to calculate surface properties of various carbon nano materials. The cost effective storage of hydrogen for mobile applications plays a key role in the development of alternatives to fossil fuels. For that reason, the application of carbon nano materials to store hydrogen by adsorption has attracted much scientific attention lately. The insights gained in the presented thesis contribute to the collective efforts and deliver more refined tools to estimate the adsorption properties of future carbon nano materials. In addition to the aforementioned, a time-of-flight mass spectrometer for educational purpose has been designed and constructed in the framework of my PhD thesis. The instrument is successfully used in various lab courses and information on the setup can be found in the Appendix of this work. (author) [de

  12. Highly Efficient Electrocatalysts for Oxygen Reduction Reaction Based on 1D Ternary Doped Porous Carbons Derived from Carbon Nanotube Directed Conjugated Microporous Polymers

    KAUST Repository

    He, Yafei; Gehrig, Dominik; Zhang, Fan; Lu, Chenbao; Zhang, Chao; Cai, Ming; Wang, Yuanyuan; Laquai, Fré dé ric; Zhuang, Xiaodong; Feng, Xinliang

    2016-01-01

    © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.One-dimensional (1D) porous materials have shown great potential for gas storage and separation, sensing, energy storage, and conversion. However, the controlled approach for preparation of 1D porous materials, especially porous organic materials, still remains a great challenge due to the poor dispersibility and solution processability of the porous materials. Here, carbon nanotube (CNT) templated 1D conjugated microporous polymers (CMPs) are prepared using a layer-by-layer method. As-prepared CMPs possess high specific surface areas of up to 623 m2 g-1 and exhibit strong electronic interactions between p-type CMPs and n-type CNTs. The CMPs are used as precursors to produce heteroatom-doped 1D porous carbons through direct pyrolysis. As-produced ternary heteroatom-doped (B/N/S) 1D porous carbons possess high specific surface areas of up to 750 m2 g-1, hierarchical porous structures, and excellent electrochemical-catalytic performance for oxygen reduction reaction. Both of the diffusion-limited current density (4.4 mA cm-2) and electron transfer number (n = 3.8) for three-layered 1D porous carbons are superior to those for random 1D porous carbon. These results demonstrate that layered and core-shell type 1D CMPs and related heteroatom-doped 1D porous carbons can be rationally designed and controlled prepared for high performance energy-related applications.

  13. Highly Efficient Electrocatalysts for Oxygen Reduction Reaction Based on 1D Ternary Doped Porous Carbons Derived from Carbon Nanotube Directed Conjugated Microporous Polymers

    KAUST Repository

    He, Yafei

    2016-10-11

    © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.One-dimensional (1D) porous materials have shown great potential for gas storage and separation, sensing, energy storage, and conversion. However, the controlled approach for preparation of 1D porous materials, especially porous organic materials, still remains a great challenge due to the poor dispersibility and solution processability of the porous materials. Here, carbon nanotube (CNT) templated 1D conjugated microporous polymers (CMPs) are prepared using a layer-by-layer method. As-prepared CMPs possess high specific surface areas of up to 623 m2 g-1 and exhibit strong electronic interactions between p-type CMPs and n-type CNTs. The CMPs are used as precursors to produce heteroatom-doped 1D porous carbons through direct pyrolysis. As-produced ternary heteroatom-doped (B/N/S) 1D porous carbons possess high specific surface areas of up to 750 m2 g-1, hierarchical porous structures, and excellent electrochemical-catalytic performance for oxygen reduction reaction. Both of the diffusion-limited current density (4.4 mA cm-2) and electron transfer number (n = 3.8) for three-layered 1D porous carbons are superior to those for random 1D porous carbon. These results demonstrate that layered and core-shell type 1D CMPs and related heteroatom-doped 1D porous carbons can be rationally designed and controlled prepared for high performance energy-related applications.

  14. A highly efficient nano-cluster artificial peroxidase and its direct electrochemistry on a nano complex modified glassy carbon electrode.

    Science.gov (United States)

    Hong, Jun; Wang, Wei; Huang, Kun; Yang, Wei-Yun; Zhao, Ying-Xue; Xiao, Bao-Lin; Gao, Yun-Fei; Moosavi-Movahedi, Zainab; Ghourchian, Hedayatollah; Moosavi-Movahedi, Ali Akbar

    2012-01-01

    A nano-cluster with highly efficient peroxide activity was constructed based on nafion (NF) and cytochrome c (Cyt c). UV-Vis spectrometry and transmission electron microscopy (TEM) methods were utilized for characterization of the nano-structured enzyme or artificial peroxidase (AP). The nano-cluster was composed of a Chain-Ball structure, with an average ball size of about 40 nm. The Michaelis-Menten (K(m)) and catalytic rate (k(cat)) constants of the AP were determined to be 2.5 ± 0.4 µM and 0.069 ± 0.001 s(-1), respectively, in 50 mM PBS at pH 7.0. The catalytic efficiency of the AP was evaluated to be 0.028 ± 0.005 µM(-1) s(-1), which was 39 ± 5% as efficient as the native horseradish peroxidase (HRP). The AP was also immobilized on a functional multi-wall carbon nanotube (MWNCTs)-gold colloid nanoparticles (AuNPs) nano-complex modified glassy carbon (GC) electrode. The cyclic voltammetry of AP on the nano complex modified GC electrode showed a pair of well-defined redox peaks with a formal potential (E°') of -45 ± 2 mV (vs. Ag/AgCl) at a scan rate of 0.05 V/s. The heterogeneous electron transfer rate constant (k(s)) was evaluated to be 0.65 s(-1). The surface concentration of electroactive AP on GC electrode (Γ) was 7 × 10(-10) mol cm(-2). The apparent Michaelis-Menten constant (K(m)(app)) was 0.23 nM.

  15. Preparation and mechanical properties of carbon nanotube-silicon nitride nano-ceramic matrix composites

    Science.gov (United States)

    Tian, C. Y.; Jiang, H.

    2018-01-01

    Carbon nanotube-silicon nitride nano-ceramic matrix composites were fabricated by hot-pressing nano-sized Si3N4 powders and carbon nanotubes. The effect of CNTs on the mechanical properties of silicon nitride was researched. The phase compositions and the microstructure characteristics of the samples as well as the distribution of carbon nanotube in the silicon nitride ceramic were analyzed by X-ray diffraction and scanning electron microscope. The results show that the microstructure of composites consists mainly of α-Si3N4, β-Si3N4, Si2N2O and carbon natubes. The addition of proper amount of carbon nanotubes can improve the fracture toughness and the flexural strength, and the optimal amount of carbon nanotube are both 3wt.%. However the Vickers hardness values decrease with the increase of carbon nanotubes content.

  16. A simple route to Develop Highly porous Nano Polypyrrole/Reduced Graphene Oxide Composite film for Selective Determination of Dopamine

    International Nuclear Information System (INIS)

    Daniel Arulraj, Abraham; Arunkumar, Arumugam; Vijayan, Muthunanthevar; Balaji Viswanath, Kamatchirajan; Vasantha, Vairathevar Sivasamy

    2016-01-01

    A highly selective sensor was developed for dopamine with electrochemically treated sodium dodecyl benzene sulfonate doped nano polypyrrole (ET-SDBS-NPPy)/reduced graphene oxide (RGO) film. First, graphene oxide (GO) was reduced on the electrode surface electrochemically and then, SDBS-NPPy film was polymerized electrochemically on the ERGO coated GCE and bare GCE also. The SDBS-NPPy/ERGO and SDBS-NPPy films were treated electrochemically in phosphate buffer solution to replace macro SDBS- anions by smaller phosphate anions. Then, the physical properties of the above composite films were characterized by scanning electron microscope (SEM) and water wettability test. The replacement of SDBS- anions by phosphate anions leaves porous structure in the polymer films and also increases the hydrophobicity in the films. Then, these composite films were applied for the determination of dopamine in the presence of ascorbic acid and uric acid. Under the optimal conditions, the linear range for dopamine detection is 0.1 μM-100.0 μM with the detection limit of 20 nM at S/N = 3. Generally, conducting polypyrrole film could sense ascorbic acid and dopamine simultaneously. However, we have proposed a simple route to synthesis a porous and hydrophobic polypyrrole composite film for selective determination of dopamine in the presence of higher concentration (five orders) of ascorbic acid and uric acid.

  17. Preparation of nano-TiO2/diatomite-based porous ceramics and their photocatalytic kinetics for formaldehyde degradation

    Science.gov (United States)

    Gao, Ru-qin; Sun, Qian; Fang, Zhi; Li, Guo-ting; Jia, Meng-zhe; Hou, Xin-mei

    2018-01-01

    Diatomite-based porous ceramics were adopted as carriers to immobilize nano-TiO2 via a hydrolysis-deposition technique. The thermal degradation of as-prepared composites was investigated using thermogravimetric-differential thermal analysis, and the phase and microstructure were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, and transmission electron microscopy. The results indicated that the carriers were encapsulated by nano-TiO2 with a thickness of 300-450 nm. The main crystalline phase of TiO2 calcined at 650°C was anatase, and the average grain size was 8.3 nm. The FT-IR absorption bands at 955.38 cm-1 suggested that new chemical bonds among Ti, O, and Si had formed in the composites. The photocatalytic (PC) activity of the composites was investigated under UV irradiation. Furthermore, the photodegradation kinetics of formaldehyde was investigated using the composites as the cores of an air cleaner. A kinetics study showed that the reaction rate constants of the gas-phase PC reaction of formaldehyde were κ = 0.576 mg·m-3·min-1 and K = 0.048 m3/mg.

  18. Multi-walled carbon nano-tubes for energy storage and production applications

    International Nuclear Information System (INIS)

    Andrews, R.; Jacques, D.; Likpa, S.; Qian, D.; Rantell, T.; Anthony, J.

    2005-01-01

    Full text of publication follows: Since their discovery, carbon nano-tubes have been proposed as candidate materials for a broad range of applications, including high strength composites, molecular electronics, and energy storage. In many cases, nano-tubes have been proposed to replace traditional carbon materials, such as activated carbons in energy storage devices. In other cases, novel applications have been proposed, such as the use of carbon nano-tube arrays in photovoltaic devices. The use of multi-walled carbon nano-tubes in energy storage devices has generated great interest due to their high inherent conductivity, layered structure, and high surface area per volume compared to traditional graphitic materials. However as produced nano-tubes do not possess ideal properties, and exhibit only modest charge storage. We have explored the charge storage abilities of nano-tubes with varying morphologies (fullerenic versus stacked cones), nano-tubes containing N or B dopants, as well as various post-treatments of the nano-tubes. The use of nano-tubes in charge storage devices will be described, as well as modification of the nano-tube surfaces or morphology to improve this performance. The synthesis of nano-tubes with several differing hetero-atom dopants will also be described, as well as the effect of heat treatment on these structures. One of the most significant problems in organic photovoltaics is the typically low charge-carrier mobility in organic thin films which, coupled with short exciton diffusion lengths, means that photo-generated charge-carrier pairs are more likely to re-combine than reach an electrode to generate current. Two organic systems with high charge-carrier mobilities are carbon nano-tubes (here, MWNTs) and acene-based organic semiconductors. We believe that blended devices based on MWNTs and organic semiconductors could lead to the next class of efficient, flexible and inexpensive organic photovoltaic systems. We have developed methods to

  19. Preparation of Multi-walled Carbon Nano tubes/ Natural Rubber Composite by Wet Mixing Method

    International Nuclear Information System (INIS)

    Azira Abdul Aziz; Azira Abdul Aziz; Che Su Mat Saad; Mohamad Rusop Mahmood

    2011-01-01

    Natural rubber/multi-walled carbon nano tubes (Nr/MWCNTs) nanocomposite is formed by incorporating nano tubes in a polymer solution and subsequently evaporating the solvent. Using this technique, nano tubes will be dispersed homogeneously in the NR matrix in an attempt to increase the mechanical properties of these nano composites. Mechanical test results show an increase in the tensile strength for up to 19 times in relation to pure NR. In addition to mechanical testing, the morphology of the MWNTs into NR was studied by Field Emission Scanning Electron Microscopy (FESEM) in order to understand the morphology of the resulting system. Slight shift noted from Raman analyses from each different wt. % of MWCNTs with the NR due to the stress transfer that indicates reinforcement of the nano tubes. (author)

  20. Carbon Microfibers with Hierarchical Porous Structure from Electrospun Fiber-Like Natural Biopolymer

    Science.gov (United States)

    Liang, Yeru; Wu, Dingcai; Fu, Ruowen

    2013-01-01

    Electrospinning offers a powerful route for building one-dimensional (1D) micro/nanostructures, but a common requirement for toxic or corrosive organic solvents during the preparation of precursor solution has limited their large scale synthesis and broad applications. Here we report a facile and low-cost way to prepare 1D porous carbon microfibers by using an electrospun fiber-like natural product, i.e., silk cocoon, as precursor. We surprisingly found that by utilizing a simple carbonization treatment, the cocoon microfiber can be directly transformed into 1D carbon microfiber of ca. 6 μm diameter with a unique three-dimensional porous network structure composed of interconnected carbon nanoparticles of 10~40 nm diameter. We further showed that the as-prepared carbon product presents superior electrochemical performance as binder-free electrodes of supercapacitors and good adsorption property toward organic vapor.

  1. A novel approach for the fabrication of carbon nanofibre/ceramic porous structures

    KAUST Repository

    Walter, Claudia

    2013-11-01

    This paper describes the fabrication of hybrid ceramic/carbon scaffolds in which carbon nanofibres and multi-walled carbon nanotubes fully cover the internal walls of a microporous ceramic structure that provides mechanical stability. Freeze casting is used to fabricate a porous, lamellar ceramic (Al2O3) structure with aligned pores whose width can be controlled between 10 and 90μm. Subsequently, a two step chemical vapour deposition process that uses iron as a catalyst is used to grow the carbon nanostructures inside the scaffold. This catalyst remains in the scaffold after the growth process. The formation of the alumina scaffold and the influence of its structure on the growth of nanofibres and tubes are investigated. A set of growth conditions is determined to produce a dense covering of the internal walls of the porous ceramic with the carbon nanostructures. The limiting pore size for this process is located around 25μm. © 2013 Elsevier Ltd.

  2. Condiment-Derived 3D Architecture Porous Carbon for Electrochemical Supercapacitors.

    Science.gov (United States)

    Qian, Wenjing; Zhu, Jingyue; Zhang, Ye; Wu, Xiao; Yan, Feng

    2015-10-07

    The one-step synthesis of porous carbon nanoflakes possessing a 3D texture is achieved by cooking (carbonization) a mixture containing two condiments, sodium glutamate (SG) and sodium chloride, which are commonly used in kitchens. The prepared 3D porous carbons are composed of interconnected carbon nanoflakes and possess instinct heteroatom doping such as nitrogen and oxygen, which furnishes the electrochemical activity. The combination of micropores and mesopores with 3D configurations facilitates persistent and fast ion transport and shorten diffusion pathways for high-performance supercapacitor applications. Sodium glutamate carbonized at 800 °C exhibits high charge storage capacity with a specific capacitance of 320 F g(-1) in 6 m KOH at a current density of 1 A g(-1) and good stability over 10,000 cycles. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Oxygen-rich hierarchical porous carbon made from pomelo peel fiber as electrode material for supercapacitor

    Science.gov (United States)

    Li, Jing; Liu, Wenlong; Xiao, Dan; Wang, Xinhui

    2017-09-01

    Oxygen-rich hierarchical porous carbon has been fabricated using pomelo peel fiber as a carbon source via an improved KOH activation method. The morphology and chemical composition of the obtained carbon materials were characterized by X-ray diffraction (XRD), X-ray photoelectron spectra (XPS), electron microscopy (EM), Raman spectra and elemental analysis. The unique porous structure with abundant oxygen functional groups is favorable to capacitive behavior, and the as-prepared carbon material exhibits high specific capacitance of 222.6 F g-1 at 0.5 A g-1 in 6 M KOH and superior stability over 5000 cycles. This work not only describes a simple way to prepare high-performance carbon material from the discarded pomelo peel, but also provides a strategy for its disposal issue and contributes to the environmental improvement.

  4. Zinc and Carbonate Co-Substituted Nano-Hydroxyapatite

    Science.gov (United States)

    Girija, E. K.; Kumar, G. Suresh; Thamizhavel, A.

    2011-07-01

    Synthesis of Zn or CO32- substituted nano-hydroxyapatite (HA) and its physico-chemical properties have been well documented. However, the effects of the simultaneous substitution of Zn and CO32- in nano-HA have not been reported. In the present study, Zn and CO32- substitutions in nano HA independently and concurrently have been done by wet precipitation method and characterized by XRD and FT-IR for its phase purity and chemical homogeneity. Further modulations of the bioactivity and thermal stability of HA due to the substitutions have been studied.

  5. Template-directed synthesis of pillared-porous carbon nanosheet architectures: High-performance electrode materials for supercapacitors

    Energy Technology Data Exchange (ETDEWEB)

    Fan, Zhuangjun; Liu, Yang; Yan, Jun; Wang, Qian; Wei, Tong [Key Laboratory of Superlight Materials and Surface Technology, Ministry of Education College of Material Science and Chemical Engineering, Harbin Engineering University, Harbin (China); Ning, Guoqing [State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Beijing, Changping (China); Zhi, Linjie [National Center for Nanoscience and Technology of China, Zhongguancun, Beijing (China); Wei, Fei [Beijing Key Laboratory of Green Chemical Reaction Engineering and Technology, Department of Chemical Engineering, Tsinghua University, Beijing (China)

    2012-04-15

    3D pillared-porous carbon nanosheets with supporting carbon pillars between the carbon layers is prepared by the carbonization of pitch on porous MgO templates. This unique structure endows the high-rate transportation of electrolyte ions and electrons throughout the electrode matrix, resulting in excellent electrochemical performance. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  6. Antimicrobial Activity of Single-Walled Carbon Nano tubes Suspended in Different Surfactants

    International Nuclear Information System (INIS)

    Dong, L.; Alex Henderson, A.; Field, Ch.

    2012-01-01

    We investigated the antibacterial activity of single-walled carbon nano tubes (SWCNTs) dispersed in surfactant solutions of sodium cholate, sodium dodecylbenzene sulfonate, and sodium dodecyl sulfate. Among the three surfactants, sodium cholate demonstrated the weakest antibacterial activity against Salmonella enterica, Escherichia coli, and Enterococcus faecium and thereby was used to disperse bundled SWCNTs in order to study nano tube antibiotic activity. SWCNTs exhibited antibacterial characteristics for both S. enterica and E. coli. With the increase of nano tube concentrations from 0.3 mg/mL to 1.5 mg/mL, the growth curves had plateaus at lower absorbance values whereas the absorbance value was not obviously affected by the incubation ranging from 5?min to 2 h. Our findings indicate that carbon nano tubes could become an effective alternative to antibiotics in dealing with drug-resistant and multidrug-resistant bacterial strains because of the physical mode of bactericidal action that SWCNTs display

  7. Technologies for the 21st century: carbon nano tubes as adsorbents of metals

    International Nuclear Information System (INIS)

    Alguacil, F. J.; Cerpa, A.; Lado, I.; Lopez, F. A.

    2014-01-01

    Nowadays and in the recent past when the word nano appeared in almost anything it attracted immediate attention and interest, this is why carbon nano tubes, since its discovery nearly twenty years ago, caught the interest of a wide scientific and industrial population to apply the somewhat amazing properties of these nano materials in a number of applications. Among them, the removal of toxic and sometimes profitable metals from aqueous streams appeared, due to its economical and social impact, as one of the targets for their uses. This paper reviews some recent advances (2009-2013 years) in the application of carbon nano tubes materials in the removal of a variety of metals from these aqueous streams. (Author)

  8. Correlation between porosity and roughness as obtained by porous silicon nano surface scattering spectrum

    Directory of Open Access Journals (Sweden)

    R Dariani

    2015-01-01

    Full Text Available Reflection spectra of four porous silicon samples under etching times of 2, 6, 10, and 14 min with current density of 10 mA/cm2 were measured. Reflection spectra behaviors for all samples were the same, but their intensities were different and decreased by increasing the etching time. The similar behavior of reflection spectra could be attributed to the electrolyte solution concentration which was the same during fabrication and reduction of reflection spectrum due to the reduction of particle size. Also, the region for the lowest intensity at reflection spectra was related to porous silicon energy gap which shows blue shift for porous silicon energy gap. Roughness study of porous silicon samples was done by scattering spectra measurements, Rayleigh criteria, and Davis-Bennet equation. Scattering spectra of the samples were measured at 10, 15, and 20 degrees by using spectrophotometer. Reflected light intensity reduced by increasing the scattering angle except for the normal scattering which agreed with Rayleigh criteria. Also, our results showed that by increasing the etching time, porosity (sizes and numbers of pores increases and therefore light absorption increases and scattering from surface reduces. But since scattering varies with the observation scale (wavelength, the relationship between scattering and porosity differs by varying the observation scale (wavelength

  9. Synthesis of sulfonated porous carbon nanospheres solid acid by a facile chemical activation route

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Binbin, E-mail: changbinbin806@163.com; Guo, Yanzhen; Yin, Hang; Zhang, Shouren; Yang, Baocheng, E-mail: baochengyang@yahoo.com

    2015-01-15

    Generally, porous carbon nanospheres materials are usually prepared via a template method, which is a multi-steps and high-cost strategy. Here, we reported a porous carbon nanosphere solid acid with high surface area and superior porosity, as well as uniform nanospheical morphology, which prepared by a facile chemical activation with ZnCl{sub 2} using resorcinol-formaldehyde (RF) resins spheres as precursor. The activation of RF resins spheres by ZnCl{sub 2} at 400 °C brought high surface area and large volume, and simultaneously retained numerous oxygen-containing and hydrogen-containing groups due to the relatively low processing temperature. The presence of these functional groups is favorable for the modification of –SO{sub 3}H groups by a followed sulfonation treating with sulphuric acid and organic sulfonic acid. The results of N{sub 2} adsorption–desorption and electron microscopy clearly showed the preservation of porous structure and nanospherical morphology. Infrared spectra certified the variation of surface functional groups after activation and the successful modification of –SO{sub 3}H groups after sulfonation. The acidities of catalysts were estimated by an indirect titration method and the modified amount of –SO{sub 3}H groups were examined by energy dispersive spectra. The results suggested sulfonated porous carbon nanospheres catalysts possessed high acidities and –SO{sub 3}H densities, which endowed their significantly catalytic activities for biodiesel production. Furthermore, their excellent stability and recycling property were also demonstrated by five consecutive cycles. - Graphical abstract: Sulfonated porous carbon nanospheres with high surface area and superior catalytic performance were prepared by a facile chemical activation route. - Highlights: • Porous carbon spheres solid acid prepared by a facile chemical activation. • It owns high surface area, superior porosity and uniform spherical morphology. • It possesses

  10. Porous sheet-like and sphere-like nano-architectures of SnO2 nanoparticles via a solvent-thermal approach and their gas-sensing performances

    International Nuclear Information System (INIS)

    Jie Liu; Tang, Xin-Cun; Xiao, Yuan-Hua; Hai Jia,; Gong, Mei-Li; Huang, Fu-Qin

    2013-01-01

    Highlights: • Porous sheet-like and sphere-like nano-architectures of SnO 2 nanoparticles have been prepared. • A solvent-thermal approach without surfactant or polymer templates simply by changing the volume ratio of DMF to water. • The formation mechanism of nano-architectures is proposed in this article. • Porous sphere-like SnO 2 nano-architectures exhibit good sensitivity to the reduce vapors tested. • Sheet-like materials show better selectivity to ethanol. -- Abstract: Porous sheet-like and sphere-like nano-architectures of SnO 2 nanoparticles have been prepared via a solvent-thermal approach in the absence of any surfactant or polymer templates by simply changing the volume ratio of DMF to water. The nano-materials have been characterized by FESEM, XRD, IR, TEM and BET. A mechanism for the formation of nano-architectures is also proposed based on the assembly behaviors of DMF in water. The gas sensors constructed with porous sphere-like SnO 2 nano-architectures exhibit much higher sensitivity to the reduce vapors tested, compared to those from porous sheet-like SnO 2 materials, while the sheet-like materials show better selectivity to ethanol. The nano-architectures fabricated with the facile method are promising candidates for building chemical sensors with tunable performances

  11. Synthesis of selenium/EDTA-derived porous carbon composite as a Li–Se battery cathode

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Chenhao, E-mail: zhaochenhao123456@163.com; Fang, Shuzhen; Hu, Zhibiao, E-mail: zhibiaohu@163.com; Qiu, Sheng’en; Liu, Kaiyu [LongYan University, College of Chemistry & Materials Science (China)

    2016-07-15

    The carbon substrate with unique 3D macroporous structure has been prepared through the immediate carbonization of ethylenediaminetetraacetic acid (EDTA) and KOH mixture. The porous carbon composed of micro- and small mesoporous (2–5 nm) structure has a BET specific surface area of 1824.8 m{sup 2} g{sup −1}. The amorphous and nanosized Se is uniformly encapsulated into the porous structure of porous carbon using melting diffusion route, and the weight content of Se in target Se/C composite can be as high as ~50 %. As an Li–Se battery cathode, the Se/C composite delivers a reversible (2nd) discharge capacity of 597.4 mAh g{sup −1} at 0.24C and retains a discharge capacity of 538.4 mAh g{sup −1} at 0.24C after 100 cycles. Furthermore, the composite also has a stable capacity of 291.0 mAh g{sup −1} at a high current of 4.8C. The high specific area and good porous size of EDTA-derived carbon substrate may a be responsibility for the excellent electrochemical performances of Se/C composite.

  12. Fabrication of nano porous with heavy ions in plastics for the oil industry

    International Nuclear Information System (INIS)

    Balcazar, M.; Tavera, L.; Mendoza, D.; Mut, A.

    2003-01-01

    The natural gas has undesirable concentrations of other gases like the nitrogen that reduces the heat capacity of the gas. It is required to develop separation technology to increase the caloric value of the gas. Among the technology in development for the separation of these gases there are the nano membranes; these are polymeric material that when synthesizing them form nano pores that allow the selective separation of the gas. Another form of creating these nano pores with uniform and controlled pore size, is irradiating a polymeric material with heavy ions. The energy loss of the heavy ion produces cylindrical damages around its trajectory in a diameter among 30 x 10 -10 m and 100 x 10 -10 m. This damage breaks the chains of the polymer making it susceptible to the corrosion of appropriate chemical agents that allow to create a pore of the size of some nanometers in the polymer. The basic mechanisms of the interaction of the ions with the polymer are important for the controlled creation, the observation and analysis of these nano pores. One of the more appropriate techniques for the visualization and analysis of the geometry of the produced damages, it is the scanning electron and of the atomic force microscopies. The present work has as objective to define the basic parameters of the interaction of the ion with the polymer that intervene in the fabrication of this nano pores. The conditions of the chemical corrosion process are presented for the creation of micro pores in two polymers CR39 and Makrofol produced by fission fragments and alpha particles. A characterization of the diameters and of the damages profile is make. The obtained results are related with the mechanisms of loss of energy of the ions in the matter and the particles identification in function of the damage geometry. (Author)

  13. Formation of carbon nano- and micro-structures on C+1 irradiated copper surfaces

    International Nuclear Information System (INIS)

    Ahmad, Shoaib

    2013-01-01

    A series of experiments has identified mechanisms of carbon nano- and micro-structure formation at room temperature, without catalyst and in the environment of immiscible metallic surroundings. The structures include threaded nano fibres, graphitic sheets and carbon onions. Copper as substrate was used due to its immiscibility with carbon. Energetic carbon ions (C + 1 ) of 0.2–2.0 MeV irradiated Cu targets. Cu substrates, apertures and 3 mm dia TEM Cu grids were implanted with the carbon. We observed wide range of μm-size structures formed on Cu grids and along the edges of the irradiated apertures. These are shown to be threaded nano fibers (TNF) of few μm thicknesses with lengths varying from 10 to 3000 μm. Secondary electron microscopy (SEM) identifies the μm-size structures while Confocal microscopy was used to learn about the mechanisms by which C + 1 irradiated Cu provides the growth environment. Huge carbon onions of diameters ranging from hundreds of nm to μm were observed in the as-grown and annealed samples. Transformations of the nanostructures were observed under prolonged electron irradiations of SEM and TEM. A mechanism for the formation of carbon nano- and micro-structures is proposed.

  14. Construct 3D porous hollow Co3O4 micro-sphere: A potential oxidizer of nano-energetic materials with superior reactivity

    Science.gov (United States)

    Wang, Jun; Zheng, Bo; Qiao, Zhiqiang; Chen, Jin; Zhang, Liyuan; Zhang, Long; Li, Zhaoqian; Zhang, Xingquan; Yang, Guangcheng

    2018-06-01

    High energy density and rapid reactivity are the future trend for nano-energetic materials. Energetic performance of nano-energetic materials depends on the interfacial diffusion and mass transfer during the reacted process. However, the development of desired structure to significantly enhance reactivity still remains challenging. Here we focused on the design and preparation of 3D porous hollow Co3O4 micro-spheres, in which gas-blowing agents (air) and maximize interfacial interactions were introduced to enhance mass transport and reduce the diffusion distance between the oxidizer and fuel (Aluminum). The 3D hierarchical Co3O4/Al based nano-energetic materials show a low-onset decomposition temperature (423 °C), and high heat output (3118 J g-1) resulting from porous and hollow nano-structure of Co3O4 micro-spheres. Furthermore, 3D hierarchical Co3O4/Al arrays were directly fabricated on the silicon substrate, which was fully compatible with silicon-based microelectromechanical systems to achieve functional nanoenergetics-on-a-chip. This approach provides a simple and efficient way to fabricate 3D ordered nano-energetic arrays with superior reactivity and the potential on the application in micro-energetic devices.

  15. N-doped polypyrrole-based porous carbons for CO{sub 2} capture

    Energy Technology Data Exchange (ETDEWEB)

    Sevilla, Marta; Valle-Vigon, Patricia; Fuertes, Antonio B. [Instituto Nacional del Carbon (CSIC), P.O. Box 73, 33080 Oviedo (Spain)

    2011-07-22

    Highly porous N-doped carbons have been successfully prepared by using KOH as activating agent and polypyrrole (PPy) as carbon precursor. These materials were investigated as sorbents for CO{sub 2} capture. The activation process was carried out under severe (KOH/PPy = 4) or mild (KOH/PPy = 2) activation conditions at different temperatures in the 600-800 C range. Mildly activated carbons have two important characteristics: i) they contain a large number of nitrogen functional groups (up to 10.1 wt% N) identified as pyridonic-N with a small proportion of pyridinic-N groups, and ii) they exhibit, in relation to the carbons prepared with KOH/PPy = 4, narrower micropore sizes. The combination of both of these properties explains the large CO{sub 2} adsorption capacities of mildly activated carbon. In particular, a very high CO{sub 2} adsorption uptake of 6.2 mmol.g{sup -1} (0 C) was achieved for porous carbons prepared with KOH/PPy = 2 and 600 C (1700 m{sup 2}.g{sup -1}, pore size {approx} 1 nm and 10.1 wt% N. Furthermore, we observed that these porous carbons exhibit high CO{sub 2} adsorption rates, a good selectivity for CO{sub 2}-N{sub 2} separation and it can be easily regenerated. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  16. Hierarchically structured, nitrogen-doped carbon membranes

    KAUST Repository

    Wang, Hong; Wu, Tao

    2017-01-01

    The present invention is a structure, method of making and method of use for a novel macroscopic hierarchically structured, nitrogen-doped, nano-porous carbon membrane (HNDCMs) with asymmetric and hierarchical pore architecture that can be produced

  17. Preparing electrochemical active hierarchically porous carbons for detecting nitrite in drinkable water

    KAUST Repository

    Ding, Baojun

    2016-01-13

    A class of hierarchically porous carbons were prepared by a facile dual-templating approach. The obtained samples were characterized by scanning electron microscopy, X-ray diffraction, Raman spectroscopy, Brunaner-Emmett-Teller measurement and electrochemical work station, respectively. The porous carbons could possess large specific surface area, interconnected pore structures, high conductivity and graphitizing degree. The resulting materials were used to prepare integrated modified electrodes. Based on the experimental results, the as-prepared hierarchically porous graphite (HPG) modified electrode showed the best electroactive performances toward the detection of nitrite with a detection limit of 8.1 × 10-3 mM. This HPG electrode was also repeatable and stable for 6 weeks. Moreover, this electrode was used for the determination of nitrite in drinkable water, and had acceptable recoveries. © The Royal Society of Chemistry 2016.

  18. Facile preparation of porous carbon from coffee bean waste using low temperature solvothermal method

    Science.gov (United States)

    Baroroh, L. A. Al; Fitria, D.; Amal, M. I.; Wismogroho, A. S.; Widayatno, W. B.

    2018-03-01

    In this study, porous carbon made from coffee bean waste (CBW) was carbonized at 500 °C, 600 °C, and 700 °C to find effective temperature. It is verified from the IR spectrum that carbonization process at certain temperature can effectively break cellulose bonding and make aromatics functional group while preserving its carbon structure. The TG-DTA curve shows four stages of decomposition process and confirms most effective carbonization temperature. Activation process of as-carbonized CBW was carried out using solvothermal method in KOH and NH4OH steam environment at 200 °C with variation of 30%, 40%, and 50% solvothermal volume. Scanning electron micrographs reveals significant increase of porosity on the carbon surface and differences of structural pores between the variations. The results show the possible potential of utilizing low temperature-solvothermal method for nanoporous carbon material.

  19. Separation of Hydrogen from Carbon Dioxide through Porous Ceramics

    Directory of Open Access Journals (Sweden)

    Taro Shimonosono

    2016-11-01

    Full Text Available The gas permeability of α-alumina, yttria-stabilized zirconia (YSZ, and silicon carbide porous ceramics toward H2, CO2, and H2–CO2 mixtures were investigated at room temperature. The permeation of H2 and CO2 single gases occurred above a critical pressure gradient, which was smaller for H2 gas than for CO2 gas. When the Knudsen number (λ/r ratio, λ: molecular mean free path, r: pore radius of a single gas was larger than unity, Knudsen flow became the dominant gas transportation process. The H2 fraction for the mixed gas of (20%–80% H2–(80%–20% CO2 through porous Al2O3, YSZ, and SiC approached unity with decreasing pressure gradient. The high fraction of H2 gas was closely related to the difference in the critical pressure gradient values of H2 and CO2 single gas, the inlet mixed gas composition, and the gas flow mechanism of the mixed gas. Moisture in the atmosphere adsorbed easily on the porous ceramics and affected the critical pressure gradient, leading to the increased selectivity of H2 gas.

  20. Nitrogen-doped porous carbon monoliths from polyacrylonitrile (PAN) and carbon nanotubes as electrodes for supercapacitors

    Science.gov (United States)

    Wang, Yanqing; Fugetsu, Bunshi; Wang, Zhipeng; Gong, Wei; Sakata, Ichiro; Morimoto, Shingo; Hashimoto, Yoshio; Endo, Morinobu; Dresselhaus, Mildred; Terrones, Mauricio

    2017-01-01

    Nitrogen-doped porous activated carbon monoliths (NDP-ACMs) have long been the most desirable materials for supercapacitors. Unique to the conventional template based Lewis acid/base activation methods, herein, we report on a simple yet practicable novel approach to production of the three-dimensional NDP-ACMs (3D-NDP-ACMs). Polyacrylonitrile (PAN) contained carbon nanotubes (CNTs), being pre-dispersed into a tubular level of dispersions, were used as the starting material and the 3D-NDP-ACMs were obtained via a template-free process. First, a continuous mesoporous PAN/CNT based 3D monolith was established by using a template-free temperature-induced phase separation (TTPS). Second, a nitrogen-doped 3D-ACM with a surface area of 613.8 m2/g and a pore volume 0.366 cm3/g was obtained. A typical supercapacitor with our 3D-NDP-ACMs as the functioning electrodes gave a specific capacitance stabilized at 216 F/g even after 3000 cycles, demonstrating the advantageous performance of the PAN/CNT based 3D-NDP-ACMs. PMID:28074847

  1. Nitrogen-doped porous carbon monoliths from polyacrylonitrile (PAN) and carbon nanotubes as electrodes for supercapacitors.

    Science.gov (United States)

    Wang, Yanqing; Fugetsu, Bunshi; Wang, Zhipeng; Gong, Wei; Sakata, Ichiro; Morimoto, Shingo; Hashimoto, Yoshio; Endo, Morinobu; Dresselhaus, Mildred; Terrones, Mauricio

    2017-01-11

    Nitrogen-doped porous activated carbon monoliths (NDP-ACMs) have long been the most desirable materials for supercapacitors. Unique to the conventional template based Lewis acid/base activation methods, herein, we report on a simple yet practicable novel approach to production of the three-dimensional NDP-ACMs (3D-NDP-ACMs). Polyacrylonitrile (PAN) contained carbon nanotubes (CNTs), being pre-dispersed into a tubular level of dispersions, were used as the starting material and the 3D-NDP-ACMs were obtained via a template-free process. First, a continuous mesoporous PAN/CNT based 3D monolith was established by using a template-free temperature-induced phase separation (TTPS). Second, a nitrogen-doped 3D-ACM with a surface area of 613.8 m 2 /g and a pore volume 0.366 cm 3 /g was obtained. A typical supercapacitor with our 3D-NDP-ACMs as the functioning electrodes gave a specific capacitance stabilized at 216 F/g even after 3000 cycles, demonstrating the advantageous performance of the PAN/CNT based 3D-NDP-ACMs.

  2. Multi-template synthesis of hierarchically porous carbon spheres with potential application in supercapacitors

    NARCIS (Netherlands)

    Zhou, Weizheng; Lin, Zhixing; Tong, Gangsheng; Stoyanov, Simeon D.; Yan, Deyue; Mai, Yiyong; Zhu, Xinyuan

    2016-01-01

    A new and simple multi-template approach towards hierarchical porous carbon (HPC) materials was reported. HPC spheres were prepared by using hierarchical silica capsules (HSCs) as the hard template and triblock copolymer Pluronic P123 as the soft template. Three types of pores were tunably

  3. Flexible and elastic porous poly(trimethylene carbonate) structures for use in vascular tissue engineering

    NARCIS (Netherlands)

    Song, Y.; Kamphuis, Marloes; Zhang Zheng, Z.Z.; Zhang, Z.; Sterk, L.M.Th.; Vermes, I.; Poot, Andreas A.; Feijen, Jan; Grijpma, Dirk W.

    Biocompatible and elastic porous tubular structures based on poly(1,3-trimethylene carbonate), PTMC, were developed as scaffolds for tissue engineering of small-diameter blood vessels. High-molecular-weight PTMC (Mn = 4.37 × 105) was cross-linked by gamma-irradiation in an inert nitrogen atmosphere.

  4. Templated diamond growth on porous carbon foam decorated with polyvinyl alcohol-nanodiamond composite

    Czech Academy of Sciences Publication Activity Database

    Varga, Marián; Stehlík, Štěpán; Kaman, Ondřej; Ižák, Tibor; Domonkos, Mária; Lee, D.S.; Kromka, Alexander

    2017-01-01

    Roč. 119, Aug (2017), s. 124-132 ISSN 0008-6223 R&D Projects: GA ČR GC15-22102J Institutional support: RVO:68378271 Keywords : nucleation * polyvinyl alcohol * nanodiamonds * carbon foam Subject RIV: JJ - Other Materials OBOR OECD: Nano-materials (production and properties) Impact factor: 6.337, year: 2016

  5. Biomass-derived porous carbon modified glass fiber separator as polysulfide reservoir for Li-S batteries.

    Science.gov (United States)

    Selvan, Ramakrishnan Kalai; Zhu, Pei; Yan, Chaoi; Zhu, Jiadeng; Dirican, Mahmut; Shanmugavani, A; Lee, Yun Sung; Zhang, Xiangwu

    2018-03-01

    Biomass-derived porous carbon has been considered as a promising sulfur host material for lithium-sulfur batteries because of its high conductive nature and large porosity. The present study explored biomass-derived porous carbon as polysulfide reservoir to modify the surface of glass fiber (GF) separator. Two different carbons were prepared from Oak Tree fruit shells by carbonization with and without KOH activation. The KOH activated porous carbon (AC) provides a much higher surface area (796 m 2  g -1 ) than pyrolized carbon (PC) (334 m 2  g -1 ). The R factor value, calculated from the X-ray diffraction pattern, revealed that the activated porous carbon contains more single-layer sheets with a lower degree of graphitization. Raman spectra also confirmed the presence of sp 3 -hybridized carbon in the activated carbon structure. The COH functional group was identified through X-ray photoelectron spectroscopy for the polysulfide capture. Simple and straightforward coating of biomass-derived porous carbon onto the GF separator led to an improved electrochemical performance in Li-S cells. The Li-S cell assembled with porous carbon modified GF separator (ACGF) demonstrated an initial capacity of 1324 mAh g -1 at 0.2 C, which was 875 mAh g -1 for uncoated GF separator (calculated based on the 2nd cycle). Charge transfer resistance (R ct ) values further confirmed the high ionic conductivity nature of porous carbon modified separators. Overall, the biomass-derived activated porous carbon can be considered as a promising alternative material for the polysulfide inhibition in Li-S batteries. Copyright © 2017 Elsevier Inc. All rights reserved.

  6. Porous carbon with a large surface area and an ultrahigh carbon purity via templating carbonization coupling with KOH activation as excellent supercapacitor electrode materials

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Fei; Gao, Jihui, E-mail: gaojh@hit.edu.cn; Liu, Xin; Pi, Xinxin; Yang, Yuqi; Wu, Shaohua

    2016-11-30

    Highlights: • Simple templating carbonization method was developed to obtain porous carbons. • Surface etching by KOH activation greatly boosts surface area and carbon purity. • The as-obtained porous carbon delivers a high capacitance of 275 F g{sup −1}. • Symmetric supercapacitor can achieved high energy density and power density. - Abstract: Large surface area and good structural stability, for porous carbons, are two crucial requirements to enable the constructed supercapacitors with high capacitance and long cycling lifespan. Herein, we successfully prepare porous carbon with a large surface area (3175 m{sup 2} g{sup −1}) and an ultrahigh carbon purity (carbon atom ratio of 98.25%) via templating carbonization coupling with KOH activation. As-synthesized MTC-KOH exhibits excellent performances as supercapacitor electrode materials in terms of high specific capacitance and ultrahigh cycling stability. In a three electrode system, MTC-KOH delivers a high capacitance of 275 F g{sup −1} at 0.5 A g{sup −1} and still 120 F g{sup −1} at a high rate of 30 A g{sup −1}. There is almost no capacitance decay even after 10,000 cycles, demonstrating outstanding cycling stability. In comparison, pre-activated MTC with a hierarchical pore structure shows a better rate capability than microporous MTC-KOH. Moreover, the constructed symmetric supercapacitor using MTC-KOH can achieve high energy densities of 8.68 Wh kg{sup −1} and 4.03 Wh kg{sup −1} with the corresponding power densities of 108 W kg{sup −1} and 6.49 kW kg{sup −1}, respectively. Our work provides a simple design strategy to prepare highly porous carbons with high carbon purity for supercapacitors application.

  7. Porous carbon with a large surface area and an ultrahigh carbon purity via templating carbonization coupling with KOH activation as excellent supercapacitor electrode materials

    International Nuclear Information System (INIS)

    Sun, Fei; Gao, Jihui; Liu, Xin; Pi, Xinxin; Yang, Yuqi; Wu, Shaohua

    2016-01-01

    Highlights: • Simple templating carbonization method was developed to obtain porous carbons. • Surface etching by KOH activation greatly boosts surface area and carbon purity. • The as-obtained porous carbon delivers a high capacitance of 275 F g −1 . • Symmetric supercapacitor can achieved high energy density and power density. - Abstract: Large surface area and good structural stability, for porous carbons, are two crucial requirements to enable the constructed supercapacitors with high capacitance and long cycling lifespan. Herein, we successfully prepare porous carbon with a large surface area (3175 m 2 g −1 ) and an ultrahigh carbon purity (carbon atom ratio of 98.25%) via templating carbonization coupling with KOH activation. As-synthesized MTC-KOH exhibits excellent performances as supercapacitor electrode materials in terms of high specific capacitance and ultrahigh cycling stability. In a three electrode system, MTC-KOH delivers a high capacitance of 275 F g −1 at 0.5 A g −1 and still 120 F g −1 at a high rate of 30 A g −1 . There is almost no capacitance decay even after 10,000 cycles, demonstrating outstanding cycling stability. In comparison, pre-activated MTC with a hierarchical pore structure shows a better rate capability than microporous MTC-KOH. Moreover, the constructed symmetric supercapacitor using MTC-KOH can achieve high energy densities of 8.68 Wh kg −1 and 4.03 Wh kg −1 with the corresponding power densities of 108 W kg −1 and 6.49 kW kg −1 , respectively. Our work provides a simple design strategy to prepare highly porous carbons with high carbon purity for supercapacitors application.

  8. Potassium vapor assisted preparation of highly graphitized hierarchical porous carbon for high rate performance supercapacitors

    Science.gov (United States)

    Liu, Zheng; Zeng, Ying; Tang, Qunli; Hu, Aiping; Xiao, Kuikui; Zhang, Shiying; Deng, Weina; Fan, Binbin; Zhu, Yanfei; Chen, Xiaohua

    2017-09-01

    Ultrahigh graphitized carbon microspheres with rich hierarchical pores (AGHPCM-1) have been successfully synthesized through the one-step activation-carbonization strategy (OACS) with porous sulfonated poly-divinylbenzene as the carbon precursor, iron as the hard template and catalyst, and potassium hydroxide (KOH) as activation agent. Through the XRD, TEM, Raman and BET analysis, AGHPCM-1 shows very high graphitization degree and rich micro-, meso- and macro-pores. More importantly, the mechanism for KOH to improve the graphitization degree of carbon materials in OACS has been illustrated by the thermodynamical theory. The tremendous heat releasing from the reaction between the catalyst precursor of Fe2O3 and potassium vapor plays a key role in the formation of graphitized carbon. It may provide a general direction to prepare highly graphitized porous carbon at a moderate temperature. Integrating the advantages of high graphitization degree and rich hierarchical porous structure, the AGHPCM-1 exhibits an excellent rate performance with a response to up to the high current density of 150 A g-1 and high scan rate of 2000 mV s-1. No obvious capacitance decay can be observed after 10000 charge/discharge cycles even at the high current density of 20 A g-1.

  9. Controlling porosity of porous carbon cathode for lithium oxygen batteries: Influence of micro and meso porosity

    Science.gov (United States)

    Kim, Minjae; Yoo, Eunjoo; Ahn, Wha-Seung; Shim, Sang Eun

    2018-06-01

    In rechargeable lithium-oxygen (Li-O2) batteries, the porosity of porous carbon materials plays a crucial role in the electrochemical performance serving as oxygen diffusion path and Li ion transfer passage. However, the influence of optimization of porous carbon as an air electrode on cell electrochemical performance remains unclear. To understand the role of carbon porosity in Li-O2 batteries, carbon materials featuring controlled pore sizes and porosity, including C-800 (nearly 96% microporous) and AC-950 (55:45 micro/meso porosity), are designed and synthesized by carbonization using a triazine-based covalent organic polymer (TCOP). We find that the microporous C-800 cathode allows 120 cycles with a limited capacity of 1000 mAh g-1, about 2 and 10 times higher than that of mixed-porosity AC-950 and mesoporous CMK-3, respectively. Meanwhile, the specific discharge capacity of the C-800 electrode at 200 mA g-1 is 6003 mAh g-1, which is lower than that of the 8433 and 9960 mAh g-1 when using AC-950 and CMK-3, respectively. This difference in the electrochemical performance of the porous carbon cathode with different porosity causes to the generation and decomposition of Li2O2 during the charge and discharge cycle, which affects oxygen diffusion and Li ion transfer.

  10. Functionalized Multi walled Carbon Nano tubes-Reinforced Viny lester/Epoxy Blend Based Nano composites: Enhanced Mechanical, Thermal, and Electrical Properties

    International Nuclear Information System (INIS)

    Praharaj, A. P.; Behera, D.; Bastia, T. K.; Rout, A. K.

    2015-01-01

    This paper presents a study on the mechanical, thermal, and electrical characterization of a new class of low cost multiphase nano composites consisting of Vinyl ester resin/epoxy (VER/EP) blend (40:60 w/w) reinforced with amine functionalized multi walled carbon nano tubes (f-MWCNTs). Five different sets of VER/EP nano composites are fabricated with addition of 0, 1, 3, 5, and 7 wt.% of f-MWCNTs. A detailed investigation of mechanical properties like tensile strength, impact strength, Young’s modulus, and hardness, thermal properties like thermogravimetric analysis (TGA) and thermal conductivity, electrical properties like dielectric strength, dielectric constant, and electrical conductivity, and corrosive and swelling properties of the nano composites has been carried out. Here, we report significant improvement in all the above properties of the fabricated nano composites with nano filler (f-MWCNTs) addition compared to the virgin blend (0 wt. nano filler loading). The properties are best observed in case of 5 wt.% nano filler loading with gradual deterioration thereafter which may be due to the nucleating tendency of the nano filler particles. Thus the above nano composites could be a preferable candidate for a wide range of structural, thermal, electrical, and solvent based applications.

  11. Electrochemical oxidation of ascorbic acid mediated by carbon nano tubes/ Li+/ carbon paste modified solid electrode

    International Nuclear Information System (INIS)

    Goh, J.K.; Tan, W.T.

    2008-01-01

    Multi-walled carbon nano tube (MWCNT) was used to modify BPPG electrode because of its unique structure and extraordinary properties. MWCNT modified electrode exhibited obvious enhancing and electro catalyzing effects to the oxidation of ascorbic acid using cyclic voltammetry technique. MWCNT was bonded on BPPG electrode surface using carbon paste with ratio of 30 % (w/ W) carbon paste (binder): 70 % (w/ w) MWCNT. This method of modification has lowered the capacitance background current and enabled lower detection limit of ascorbic acid concentration. The electrical conductivity property of MWCNT modified electrode was further improved with the intercalation with lithium ion and resulted in current enhancement of 2 times on the oxidation current of ascorbic acid. Parameters of pH and temperature showed significant relation to the sensitivity of MWCNT modified electrode. Under the optimized parameters, the calibration curve constructed was linear up from 50 μM to 5 mM with sensitivity of 34.5 mA M -1 . The practical application of MWCNT modified electrode was demonstrated with Vitamin C pill and orange juice. Good reproducibility and recovery of ascorbic acid concentration showed the feasibility of MWCNT modified electrode to be used in the detection of ascorbic acid in aqueous solution. This also proposed MWCNT modified BPPG electrode possessed advantages such as low detection limit, high stability, low cost and simplicity in fabrication. (author)

  12. Carbon nanotubes-porous ceramic composite by in situ CCVD growth of CNTs

    International Nuclear Information System (INIS)

    Mazumder, Sangram; Sarkar, Naboneeta; Park, Jung Gyu; Han, In Sub; Kim, Ik Jin

    2016-01-01

    A novel approach towards the formation of Carbon nanotubes-porous alumina ceramic composite was attempted by the application of three different reaction techniques. Porous alumina ceramics having micrometer pore dimensions were developed using the direct foaming technique. NaA zeolites were simultaneously synthesized and coated within the porous ceramics by an in situ hydrothermal process and were subjected to a simple ion exchange reaction for preparing the suitable catalyst material for Carbon nanotubes (CNTs) synthesis. The catalytic chemical vapour deposition (CCVD) technique was used to grow CNTs within the porous ceramics and the effect of growth time on the synthesized CNTs were investigated. Phase compositions of the samples were analysed by X-ray diffractometer (XRD). Field Emission Scanning Electron Microscopy (FESEM) and Transmission Electron Microscopy (TEM) were used for morphology, surface quality and structural analysis. Crystallinity, defects and yield were studied by Raman spectroscopy and thermogravimetric analysis (TGA). - Highlights: • Novel processing route of MWCNTs grown on Cobalt-zeolites-porous ceramics by CCVD. • CCVD time of 120 min produced MWCNTs with most prominent tube-like structure. • 120 min produced highest yield (19.46%) of CNTs with an I_D/I_G ratio of 0.88.

  13. Carbon nanotubes-porous ceramic composite by in situ CCVD growth of CNTs

    Energy Technology Data Exchange (ETDEWEB)

    Mazumder, Sangram; Sarkar, Naboneeta; Park, Jung Gyu [Institute of Processing and Application of Inorganic Materials (PAIM), Department of Materials Science and Engineering, Hanseo University, #360 Daegok-ri, Haemi-myeon, Seosan-si, Chungnam, 356-706 (Korea, Republic of); Han, In Sub [Korea Institute of Energy Research (KIER), #152 Gajeong-gu, Daejeon 305-343 (Korea, Republic of); Kim, Ik Jin, E-mail: ijkim@hanseo.ac.kr [Institute of Processing and Application of Inorganic Materials (PAIM), Department of Materials Science and Engineering, Hanseo University, #360 Daegok-ri, Haemi-myeon, Seosan-si, Chungnam, 356-706 (Korea, Republic of)

    2016-03-01

    A novel approach towards the formation of Carbon nanotubes-porous alumina ceramic composite was attempted by the application of three different reaction techniques. Porous alumina ceramics having micrometer pore dimensions were developed using the direct foaming technique. NaA zeolites were simultaneously synthesized and coated within the porous ceramics by an in situ hydrothermal process and were subjected to a simple ion exchange reaction for preparing the suitable catalyst material for Carbon nanotubes (CNTs) synthesis. The catalytic chemical vapour deposition (CCVD) technique was used to grow CNTs within the porous ceramics and the effect of growth time on the synthesized CNTs were investigated. Phase compositions of the samples were analysed by X-ray diffractometer (XRD). Field Emission Scanning Electron Microscopy (FESEM) and Transmission Electron Microscopy (TEM) were used for morphology, surface quality and structural analysis. Crystallinity, defects and yield were studied by Raman spectroscopy and thermogravimetric analysis (TGA). - Highlights: • Novel processing route of MWCNTs grown on Cobalt-zeolites-porous ceramics by CCVD. • CCVD time of 120 min produced MWCNTs with most prominent tube-like structure. • 120 min produced highest yield (19.46%) of CNTs with an I{sub D}/I{sub G} ratio of 0.88.

  14. Bioconjugate functionalization of thermally carbonized porous silicon using a radical coupling reaction†

    Science.gov (United States)

    Sciacca, Beniamino; Alvarez, Sara D.; Geobaldo, Francesco; Sailor, Michael J.

    2011-01-01

    The high stability of Salonen’s thermally carbonized porous silicon (TCPSi) has attracted attention for environmental and biochemical sensing applications, where corrosion-induced zero point drift of porous silicon-based sensor elements has historically been a significant problem. Prepared by the high temperature reaction of porous silicon with acetylene gas, the stability of this silicon carbide-like material also poses a challenge—many sensor applications require a functionalized surface, and the low reactivity of TCPSi has limited the ability to chemically modify its surface. This work presents a simple reaction to modify the surface of TCPSi with an alkyl carboxylate. The method involves radical coupling of a dicarboxylic acid (sebacic acid) to the TCPSi surface using a benzoyl peroxide initiator. The grafted carboxylic acid species provides a route for bioconjugate chemical modification, demonstrated in this work by coupling propylamine to the surface carboxylic acid group through the intermediacy of pentafluorophenol and 1-ethyl-3-[3-dimethylaminopropyl]carbodiimide hydrochloride (EDC). The stability of the carbonized porous Si surface, both before and after chemical modification, is tested in phosphate buffered saline solution and found to be superior to either hydrosilylated (with undecylenic acid) or thermally oxidized porous Si surfaces. PMID:20967329

  15. Retention and effective diffusion of model metabolites on porous graphitic carbon.

    Science.gov (United States)

    Lunn, Daniel B; Yun, Young J; Jorgenson, James W

    2017-12-29

    The study of metabolites in biological samples is of high interest for a wide range of biological and pharmaceutical applications. Reversed phase liquid chromatography is a common technique used for the separation of metabolites, but it provides little retention for polar metabolites. An alternative to C18 bonded phases, porous graphitic carbon has the ability to provide significant retention for both non-polar and polar analytes. The goal of this work is to study the retention and effective diffusion properties of porous graphitic carbon, to see if it is suitable for the wide injection bands and long run times associated with long, packed capillary-scale separations. The retention of a set of standard metabolites was studied for both stationary phases over a wide range of mobile phase conditions. This data showed that porous graphitic carbon benefits from significantly increased retention (often >100 fold) under initial gradient conditions for these metabolites, suggesting much improved ability to focus a wide injection band at the column inlet. The effective diffusion properties of these columns were studied using peak-parking experiments with the standard metabolites under a wide range of retention conditions. Under the high retention conditions, which can be associated with retention after injection loading for gradient separations, D eff /D m ∼0.1 for both the C18-bonded and porous graphitic carbon columns. As C18 bonded particles are widely, and successfully utilized for long gradient separations without issue of increasing peak width from longitudinal diffusion, this suggests that porous graphitic carbon should be amenable for long runtime gradient separations as well. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Highly stable porous silicon-carbon composites as label-free optical biosensors.

    Science.gov (United States)

    Tsang, Chun Kwan; Kelly, Timothy L; Sailor, Michael J; Li, Yang Yang

    2012-12-21

    A stable, label-free optical biosensor based on a porous silicon-carbon (pSi-C) composite is demonstrated. The material is prepared by electrochemical anodization of crystalline Si in an HF-containing electrolyte to generate a porous Si template, followed by infiltration of poly(furfuryl) alcohol (PFA) and subsequent carbonization to generate the pSi-C composite as an optically smooth thin film. The pSi-C sensor is significantly more stable toward aqueous buffer solutions (pH 7.4 or 12) compared to thermally oxidized (in air, 800 °C), hydrosilylated (with undecylenic acid), or hydrocarbonized (with acetylene, 700 °C) porous Si samples prepared and tested under similar conditions. Aqueous stability of the pSi-C sensor is comparable to related optical biosensors based on porous TiO(2) or porous Al(2)O(3). Label-free optical interferometric biosensing with the pSi-C composite is demonstrated by detection of rabbit IgG on a protein-A-modified chip and confirmed with control experiments using chicken IgG (which shows no affinity for protein A). The pSi-C sensor binds significantly more of the protein A capture probe than porous TiO(2) or porous Al(2)O(3), and the sensitivity of the protein-A-modified pSi-C sensor to rabbit IgG is found to be ~2× greater than label-free optical biosensors constructed from these other two materials.

  17. In vitro study on porous silver scaffolds prepared by electroplating method using cellular carbon skeleton as the substrate

    International Nuclear Information System (INIS)

    Guo, M.; Wang, X.; Zhou, H.M.; Li, L.; Nie, F.L.; Cheng, Y.; Zheng, Y.F.

    2012-01-01

    Porous silver scaffolds, with the porosity ranging from 68% to 81% and the apparent density ranging from 0.4 to 1 g⋅cm −3 were prepared by electroplating method using cellular carbon skeleton as the substrate. The microstructure, mechanical property, cytotoxicity and antibacterial activity of the prepared porous silver scaffold were studied. The present porous silver scaffolds had a highly three-dimensional trabecular porous structure with the porosity and the apparent density close to that of the cancellous bone. Furthermore, the mechanical property such as elastic modulus and yield strength of the porous silver scaffolds were lower than that of commercial available porous Ti and porous Ti alloys but much closer to that of the cancellous bone and porous Ta. In addition, study of in vitro behavior showed that the porous silver scaffold possessed significant antibacterial capability of inhibition of bacterial proliferation and adherence against Staphylococcus aureus and Staphylococcus epidermidis, and little cytotoxicity to Mg-63 cell line and NIH-3T3 cell line. Consequently, the porous silver scaffolds prepared by electrodeposition possess a promising application for bone implants. - Highlights: ► Porous Ag scaffolds were produced by electroplating Ag on cellular carbon skeleton. ► Porous Ag scaffolds have the porosity 68–81% and the apparent density 0.4–1 g⋅cm −3 . ► The mechanical property of porous Ag is close to cancellous bone and porous Ta. ► Porous Ag inhibits the proliferation and adherence of S. aureus and S. epidermidis.

  18. Porous MnO/C of composite nanostructure consisting of nanorods and nano-octahedra as anode of lithium ion batteries with enhanced electrochemical performances

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Yue-Feng; Xu, Gui-Liang [State Key Laboratory of Physical Chemistry of Solid Surfaces, Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005 (China); Su, Hang [College of Energy, Xiamen University, Xiamen 361005 (China); Chen, Yuan; Fang, Jun-Chuan; Wang, Qi; Huang, Ling [State Key Laboratory of Physical Chemistry of Solid Surfaces, Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005 (China); Li, Jun-Tao [College of Energy, Xiamen University, Xiamen 361005 (China); Sun, Shi-Gang, E-mail: sgsun@xmu.edu.cn [State Key Laboratory of Physical Chemistry of Solid Surfaces, Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005 (China)

    2016-08-15

    Porous MnO/C materials of composite nanostructure consisting of nanorods and nano-octahedra (denoted as nRO-MnO/C) were synthesized for the first time through a one-pot hydrothermal procedure followed by thermal annealing using PEG6000 as a soft template. When served as anode of LIBs, the nRO-MnO/C materials could maintain a reversible capacity as high as 861.3 mAh g{sup −1} after 120 cycles at a rate of 0.13 C (1 C = 755.6 mA g{sup −1}), and a stable capacity of 313.5 mAh g{sup −1} at a much higher rate of 4.16 C. Moreover, excellent long cycleability at high rate has been also evidenced by a capacity of 628.9 mAh g{sup −1} measured after 300 cycles at 1.32 C. In comparison with mono-form porous nanorods (nR-MnO/C) and mono-form porous nano-octahedra (nO-MnO/C), the enhanced electrochemical performances of the nRO-MnO/C materials are attributed to the composite nanostructure, in which the nano-octahedra contact effectively with nanorods by laying in the space between them yielding synergy effect that facilitates the electronic transportation on electrode. - Highlights: • Porous MnO/C with composite nanostructure was prepared by hydrothermal reaction. • The composite nanostructure is consisting of nanorods and nano-octahedra. • The nRO-MnO/C delivers a charge capacity of 628.9 mAh g{sup −1} after 300 cycles at 1.32 C. • The superior electrochemical performance should be owed to composite structure.

  19. Fabrication of a multifunctional nano-in-micro drug delivery platform by microfluidic templated encapsulation of porous silicon in polymer matrix.

    Science.gov (United States)

    Zhang, Hongbo; Liu, Dongfei; Shahbazi, Mohammad-Ali; Mäkilä, Ermei; Herranz-Blanco, Bárbara; Salonen, Jarno; Hirvonen, Jouni; Santos, Hélder A

    2014-07-09

    A multifunctional nano-in-micro drug delivery platform is developed by conjugating the porous silicon nanoparticles with mucoadhesive polymers and subsequent encapsulation into a pH-responsive polymer using microfluidics. The multistage platform shows monodisperse size distribution and pH-responsive payload release, and the released nanoparticles are mucoadhesive. Moreover, this platform is capable of simultaneously loading and releasing multidrugs with distinct properties. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Photocatalytic activity of self-assembled porous TiO2 nano-columns array fabricated by oblique angle sputter deposition

    Science.gov (United States)

    Shi, Pengjun; Li, Xibo; Zhang, Qiuju; Yi, Zao; Luo, Jiangshan

    2018-04-01

    A well-separated and oriented TiO2 nano-columns arrays with porous structure were fabricated by the oblique angle sputter deposition technique and subsequently annealing at 450 °C in Ar/O2 mixed atmosphere. The deposited substrate was firstly modified by a template of self-assembled close-packed arrays of 500 nm-diameter silica (SiO2) spheres. Scanning electronic microscopic (SEM) images show that the porous columnar nanostructure is formed as a result of the geometric shadowing effect and surface diffusion of the adatoms in oblique angle deposition (OAD). X-ray diffraction (XRD) measurements reveal that the physically OAD film with annealing treatment are generally mixed phase of rutile and anatase TiO2 polymorphic forms. The morphology induced absorbance and band gap tuning by different substrates was demonstrated by the UV–vis spectroscopy. The well-separated one-dimensional (1D) nano-columns array with specific large porous surface area is beneficial for charge separation in photocatalytic degradation. Compared with compact thin film, such self-assembled porous TiO2 nano-columns array fabricated by oblique angle sputter deposition performed an enhanced visible light induced photocatalytic activity by decomposing methyl orange (MO) solution. The well-designed periodic array-structured porous TiO2 films by using modified patterned substrates has been demonstrated significantly increased absorption edge in the UV-visible light region with a narrower optical band gap, which are expected to be favorable for application in photovoltaic, lithium-ion insertion and photocatalytic, etc.

  1. Coaxial stability of nano-bearings constructed by double-walled carbon nanotubes

    International Nuclear Information System (INIS)

    Huang Zaixing

    2008-01-01

    How to effectively control the coaxial stability of nano-bearings has an important influence on improving the quality of nano-bearings. Some relevant problems are studied in this paper. Firstly, we investigate basic non-coaxial modes in double-wall carbon nanotubes (DWCNTs). On the basis of analysis for these non-coaxial modes, a planar continuum model is established according to the principle of homogenization. By means of this model, a dynamic parameter λ* characterizing the coaxial stability of nano-bearings is determined. λ* is the explicit function of the angular velocity and interlayer spacing of DWCNTs. In terms of λ*, a criterion used to judge the coaxial stability of nano-bearings is given. Through discussing the influence of the angular velocity and interlayer spacing on the dynamic parameter λ*, some important conclusions are drawn

  2. Facile Fabrication of 3D Hierarchically Porous Carbon Foam as Supercapacitor Electrode Material

    Directory of Open Access Journals (Sweden)

    Yunfang Gao

    2018-04-01

    Full Text Available A hierarchically porous 3D starch-derived carbon foam (SCF with a high specific surface area (up to 1693 m2·g−1 was first prepared by a facile solvothermal treatment, in which Na2CO3 is used as both the template and activating agent. The hierarchically porous structure and high specific area endow the SCF with favorable electrochemical properties such as a high specific capacitance of 179.6 F·g−1 at 0.5 A·g−1 and a great rate capability and cycling stability, which suggest that the material can be a promising candidate for energy storage applications.

  3. Hydrogen adsorption in microporous alkali-doped carbons (single-wall carbon nano-tubes and activated carbons)

    International Nuclear Information System (INIS)

    Laurent Duclaux; Szymon Los; Michel Letellier; Philippe Azais; Roland Pellenq; Thomas Roussel; Xavier Fuhr

    2006-01-01

    Doping of microporous carbon by Li or K leads to an increase in the energy of adsorption of H 2 or D 2 molecules. Thus, the room temperature sorption capacities (at P≤3 MPa) can be higher than the ones of the raw materials after slight doping. However, the maximum H 2 (or D 2 ) storage uptake measured at T≤ 77 K is lower than the one of pristine materials as the sites of adsorption are occupied by alkali ions inserted in the micropores. The microporous adsorption sites of doped single-walled carbon nano-tubes, identified by neutron diffraction, are both the interstitial voids (in electric-arc or HiPCO tubes) in between the tubes and the central canals of the tubes (only in HiPCO tubes). (authors)

  4. Synthesis of porous carbon/silica nanostructured microfiber with ultrahigh surface area

    Science.gov (United States)

    Zhou, Dan; Dong, Yan; Cui, Liru; Lin, Huiming; Qu, Fengyu

    2014-12-01

    Carbon/silica-nanostructured microfibers were synthesized via electrospinning method using phenol-formaldehyde resin and tetraethyl orthosilicate as carbon and silica precursor with triblock copolymer Pluronic P123 as soft template. The prepared samples show uniform microfiber structure with 1 μm in diameter and dozens of microns in length. Additionally, the mesopores in the material is about 2-6 nm. When the silica component was removed by HF, the porous carbon microfibers (PCMFs) were obtained. In addition, after the carbon/silica composites were calcined in air, the porous silica microfibers (PSiMFs) were obtained, revealing the converse porous nanostructure as PCMFs. It is a simple way to prepare PCMFs and PSiMFs with silica and carbon as the template to each other. Additionally, PCMFs possess an ultrahigh specific surface area (2,092 m2 g-1) and large pore volume. The electrochemical performance of the prepared PCMF material was investigated in 6.0 M KOH electrolyte. The PCMF electrode exhibits a high specific capacitance (252 F g-1 at 0.5 A g-1). Then, superior cycling stability (97 % retention after 4,000 cycles) mainly is due to its unique nanostructure.

  5. Synthesis of porous carbon/silica nanostructured microfiber with ultrahigh surface area

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Dan; Dong, Yan; Cui, Liru; Lin, Huiming, E-mail: hiuminglin@gmail.com; Qu, Fengyu, E-mail: qufengyu2012@yahoo.cn, E-mail: qufengyu@hrbnu.edu.cn [Harbin Normal University, College of Chemistry and Chemical Engineering (China)

    2014-12-15

    Carbon/silica-nanostructured microfibers were synthesized via electrospinning method using phenol-formaldehyde resin and tetraethyl orthosilicate as carbon and silica precursor with triblock copolymer Pluronic P123 as soft template. The prepared samples show uniform microfiber structure with ∼1 μm in diameter and dozens of microns in length. Additionally, the mesopores in the material is about 2–6 nm. When the silica component was removed by HF, the porous carbon microfibers (PCMFs) were obtained. In addition, after the carbon/silica composites were calcined in air, the porous silica microfibers (PSiMFs) were obtained, revealing the converse porous nanostructure as PCMFs. It is a simple way to prepare PCMFs and PSiMFs with silica and carbon as the template to each other. Additionally, PCMFs possess an ultrahigh specific surface area (2,092 m{sup 2} g{sup −1}) and large pore volume. The electrochemical performance of the prepared PCMF material was investigated in 6.0 M KOH electrolyte. The PCMF electrode exhibits a high specific capacitance (252 F g{sup −1} at 0.5 A g{sup −1}). Then, superior cycling stability (97 % retention after 4,000 cycles) mainly is due to its unique nanostructure.

  6. Mechanochemistry-assisted synthesis of hierarchical porous carbons applied as supercapacitors

    Science.gov (United States)

    Leistenschneider, Desirée; Jäckel, Nicolas; Hippauf, Felix; Presser, Volker

    2017-01-01

    A solvent-free synthesis of hierarchical porous carbons is conducted by a facile and fast mechanochemical reaction in a ball mill. By means of a mechanochemical ball-milling approach, we obtained titanium(IV) citrate-based polymers, which have been processed via high temperature chlorine treatment to hierarchical porous carbons with a high specific surface area of up to 1814 m2 g−1 and well-defined pore structures. The carbons are applied as electrode materials in electric double-layer capacitors showing high specific capacitances with 98 F g−1 in organic and 138 F g−1 in an ionic liquid electrolyte as well as good rate capabilities, maintaining 87% of the initial capacitance with 1 M TEA-BF4 in acetonitrile (ACN) and 81% at 10 A g−1 in EMIM-BF4. PMID:28781699

  7. Mechanochemistry-assisted synthesis of hierarchical porous carbons applied as supercapacitors

    Directory of Open Access Journals (Sweden)

    Desirée Leistenschneider

    2017-07-01

    Full Text Available A solvent-free synthesis of hierarchical porous carbons is conducted by a facile and fast mechanochemical reaction in a ball mill. By means of a mechanochemical ball-milling approach, we obtained titanium(IV citrate-based polymers, which have been processed via high temperature chlorine treatment to hierarchical porous carbons with a high specific surface area of up to 1814 m2 g−1 and well-defined pore structures. The carbons are applied as electrode materials in electric double-layer capacitors showing high specific capacitances with 98 F g−1 in organic and 138 F g−1 in an ionic liquid electrolyte as well as good rate capabilities, maintaining 87% of the initial capacitance with 1 M TEA-BF4 in acetonitrile (ACN and 81% at 10 A g−1 in EMIM-BF4.

  8. Synthesis of Porous and Mechanically Compliant Carbon Aerogels Using Conductive and Structural Additives

    Directory of Open Access Journals (Sweden)

    Carlos Macias

    2016-01-01

    Full Text Available We report the synthesis of conductive and mechanically compliant monolithic carbon aerogels prepared by sol-gel polycondensation of melamine-resorcinol-formaldehyde (MRF mixtures by incorporating diatomite and carbon black additives. The resulting aerogels composites displayed a well-developed porous structure, confirming that the polymerization of the precursors is not impeded in the presence of either additive. The aerogels retained the porous structure after etching off the siliceous additive, indicating adequate cross-linking of the MRF reactants. However, the presence of diatomite caused a significant fall in the pore volumes, accompanied by coarsening of the average pore size (predominance of large mesopores and macropores. The diatomite also prevented structural shrinkage and deformation of the as-prepared monoliths upon densification by carbonization, even after removal of the siliceous framework. The rigid pristine aerogels became more flexible upon incorporation of the diatomite, favoring implementation of binderless monolithic aerogel electrodes.

  9. Nano-Tomography of Porous Geological Materials Using Focused Ion Beam-Scanning Electron Microscopy

    Directory of Open Access Journals (Sweden)

    Yang Liu

    2016-10-01

    Full Text Available Tomographic analysis using focused ion beam-scanning electron microscopy (FIB-SEM provides three-dimensional information about solid materials with a resolution of a few nanometres and thus bridges the gap between X-ray and transmission electron microscopic tomography techniques. This contribution serves as an introduction and overview of FIB-SEM tomography applied to porous materials. Using two different porous Earth materials, a diatomite specimen, and an experimentally produced amorphous silica layer on olivine, we discuss the experimental setup of FIB-SEM tomography. We then focus on image processing procedures, including image alignment, correction, and segmentation to finally result in a three-dimensional, quantified pore network representation of the two example materials. To each image processing step we consider potential issues, such as imaging the back of pore walls, and the generation of image artefacts through the application of processing algorithms. We conclude that there is no single image processing recipe; processing steps need to be decided on a case-by-case study.

  10. Nano-porous inorganic-organic hybrid solids: some new materials for hydrogen storage?

    International Nuclear Information System (INIS)

    Serre, Ch.; Loiseau, Th.; Devic, T.; Ferey, G.; Latroche, M.; Llewellyn, Ph.; Chang, J.S.

    2007-01-01

    Recently have been studied chromium and aluminium carboxylates MIL-53(Cr, Al), formed from an assembly of octahedrons chains and for hybrid solids formed with octahedrons trimers (MIL-100 and MIL-101). The compounds MIL-53(Cr, Al) are microporous (φ ∼ 8 Angstroms, while the solids MIL-100 and MIL-101 have very large porous volumes (V ∼ 380-700000 (Angstroms) 3 ), meso-pores (φ ∼ 25-34 Angstroms) and a zeolitic architecture. The resulting specific surface areas are important (between 1000 m 2 .g -1 for the MIL-53 solids, until 4000 m 2 .g -1 for the MIL-101 compound. Here is presented their hydrogen adsorption properties, at 77 K and 298 K. The hydrogen adsorption kinetics has been tested on the MIL-53(Cr) solid at 77 K. Hydrogen adsorption micro-calorimetry experiments have been carried out on these solids between 0 and 1 bar in order to obtain data on the strongest interactions between hydrogen and the porous basic structure. (O.M.)

  11. Preparation of porous carbon sphere from waste sugar solution for electric double-layer capacitor

    Science.gov (United States)

    Hao, Zhi-Qiang; Cao, Jing-Pei; Wu, Yan; Zhao, Xiao-Yan; Zhuang, Qi-Qi; Wang, Xing-Yong; Wei, Xian-Yong

    2017-09-01

    Waste sugar solution (WSS), which contains abundant 2-keto-L-gulonic acid, is harmful to the environment if discharged directly. For value-added utilization of the waste resource, a novel process is developed for preparation of porous carbon spheres by hydrothermal carbonization (HTC) of WSS followed by KOH activation. Additionally, the possible preparation mechanism of carbon spheres is proposed. The effects of hydrothermal and activation parameters on the properties of the carbon sphere are also investigated. The carbon sphere is applied to electric double-layer capacitor and its electrochemical performance is studied. These results show that the carbon sphere obtained by HTC at 180 °C for 12 h with the WSS/deionized water volume ratio of 2/3 possess the highest specific capacitance under identical activation conditions. The specific capacitance of the carbon spheres can reach 296.1 F g-1 at a current density of 40 mA g-1. Besides, excellent cycle life and good capacitance retention (89.6%) are observed at 1.5 A g-1 after 5000 cycles. This study not only provides a facile and potential method for the WSS treatment, but also achieves the high value-added recycling of WSS for the preparation of porous carbon spheres with superior electrochemical properties.

  12. N-Doped Porous Carbon Nanofibers/Porous Silver Network Hybrid for High-Rate Supercapacitor Electrode.

    Science.gov (United States)

    Meng, Qingshi; Qin, Kaiqiang; Ma, Liying; He, Chunnian; Liu, Enzuo; He, Fang; Shi, Chunsheng; Li, Qunying; Li, Jiajun; Zhao, Naiqin

    2017-09-13

    A three-dimensional cross-linked porous silver network (PSN) is fabricated by silver mirror reaction using polymer foam as the template. The N-doped porous carbon nanofibers (N-PCNFs) are further prepared on PSN by chemical vapor deposition and treated by ammonia gas subsequently. The PSN substrate serving as the inner current collector will improve the electron transport efficiency significantly. The ammonia gas can not only introduce nitrogen doping into PCNFs but also increase the specific surface area of PCNFs at the same time. Because of its large surface area (801 m 2 /g), high electrical conductivity (211 S/cm), and robust structure, the as-constructed N-PCNFs/PSN demonstrates a specific capacitance of 222 F/g at the current density of 100 A/g with a superior rate capability of 90.8% of its initial capacitance ranging from 1 to 100 A/g while applied as the supercapacitor electrode. The symmetric supercapacitor device based on N-PCNFs/PSN displays an energy density of 8.5 W h/kg with power density of 250 W/kg and excellent cycling stability, which attains 103% capacitance retention after 10 000 charge-discharge cycles at a high current density of 20 A/g, which indicates that N-PCNFs/PSN is a promising candidate for supercapacitor electrode materials.

  13. Enhanced photo-response of porous silicon photo-detectors by embeddingTitanium-dioxide nano-particles

    Science.gov (United States)

    Ali, Hiba M.; Makki, Sameer A.; Abd, Ahmed N.

    2018-05-01

    Porous silicon (n-PS) films can be prepared by photoelectochemical etching (PECE) Silicon chips n - types with 15 (mA / cm2), in 15 minutes etching time on the fabrication nano-sized pore arrangement. By using X-ray diffraction measurement and atomic power microscopy characteristics (AFM), PS was investigated. It was also evaluated the crystallites size from (XRD) for the PS nanoscale. The atomic force microscopy confirmed the nano-metric size chemical fictionalization through the electrochemical etching that was shown on the PS surface chemical composition. The atomic power microscopy checks showed the roughness of the silicon surface. It is also notified (TiO2) preparation nano-particles that were prepared by pulse laser eradication in ethanol (PLAL) technique through irradiation with a Nd:YAG laser pulses TiO2 target that is sunk in methanol using 400 mJ of laser energy. It has been studied the structural, optical and morphological of TiO2NPs. It has been detected that through XRD measurement, (TiO2) NPs have been Tetragonal crystal structure. While with AFM measurements, it has been realized that the synthesized TiO2 particles are spherical with an average particle size in the (82 nm) range. It has been determined that the energy band gap of TiO2 NPs from optical properties and set to be in (5eV) range.The transmittance and reflectance spectra have determined the TiO2 NPs optical constants. It was reported the effectiveness of TiO2 NPs expansion on the PS Photodetector properties which exposes the benefits in (Al/PS/Si/Al). The built-in tension values depend on the etching time current density and laser flounce. Al/TiO2/PS/Si/Al photo-detector heterojunction have two response peaks that are situated at 350 nm and (700 -800nm) with max sensitivity ≈ 0.7 A/W. The maximum given detectivity is 9.38at ≈ 780 nm wavelength.

  14. Porous carbon derived via KOH activation of a hypercrosslinked porous organic polymer for efficient CO_2, CH_4, H_2 adsorptions and high CO_2/N_2 selectivity

    International Nuclear Information System (INIS)

    Modak, Arindam; Bhaumik, Asim

    2015-01-01

    Microporous carbon having Brunauer-Emmett-Teller (BET) surface area of 2186 m"2 g"−"1 and micropore volume of 0.85 cm"3 g"−"1 has been synthesized via KOH induced high temperature carbonization of a non-conjugated hypercrosslinked organic polymer. Owing to the templating and activation by KOH, we have succeeded in making a microporous carbon from this porous polymer and the resultant carbon material showed high uptake for CO_2 (7.6 mmol g"−"1) and CH_4 (2.4 mmol g"−"1) at 1 atm, 273 K together with very good selectivity for the CO_2/N_2 (30.2) separation. Furthermore, low pressure (1 atm) H_2 (2.6 wt%, 77 K) and water uptake (57.4 wt%, 298 K) ability of this polymer derived porous activated carbon is noteworthy. - Graphical abstract: Microporous carbon with BET surface area of 2186 m"2 g"−"1 has been synthesized via KOH activation of a porous organic polymer and it showed high uptake for CO_2 (7.6 mmol g"−"1), CH_4 (2.4 mmol g"−"1) and H_2 (2.6 wt%) at 1 atm together with very good selectivity for CO_2. - Highlights: • Porous carbon from hypercrosslinked organic polymer. • KOH activated carbon with BET surface area 2186 m"2 g"−"1. • High CO2 uptake (7.6 mmol g"−"1) and CO_2/N_2 selectivity (30.2). • Porous carbon also showed high H_2 (2.6 wt%) and H_2O (57.4 wt%) uptakes.

  15. Ab initio calculations on hydrogen storage in porous carbons

    International Nuclear Information System (INIS)

    Maresca, O.; Marinelli, F.; Pellenq, R.J.M.; Duclaux, L.; Azais, Ph.; Conard, J.

    2005-01-01

    We have investigated through ab initio computations the possible ways to achieve efficient hydrogen storage on carbons. Firstly, we have considered how the curvature of a carbon surface could affect the chemisorption of atomic H 0 Secondly, we show that electron donor elements such as Li and K, used as dopants for the carbon substrate, strongly enhance the physi-sorption energy of H 2 , allowing in principle its storage in this type of material at room temperature under mild conditions of pressure. (authors)

  16. Synthesis of polybenzoxazine based nitrogen-rich porous carbons for carbon dioxide capture

    Science.gov (United States)

    Wan, Liu; Wang, Jianlong; Feng, Chong; Sun, Yahui; Li, Kaixi

    2015-04-01

    Nitrogen-rich porous carbons (NPCs) were synthesized from 1,5-dihydroxynaphthalene, urea, and formaldehyde based on benzoxazine chemistry by a soft-templating method with KOH chemical activation. They possess high surface areas of 856.8-1257.8 m2 g-1, a large pore volume of 0.15-0.65 cm3 g-1, tunable pore structure, high nitrogen content (5.21-5.32 wt%), and high char yields. The amount of the soft-templating agent F127 has multiple influences on the textural and chemical properties of the carbons, affecting the surface area and pore structure, impacting the compositions of nitrogen species and resulting in an improvement of the CO2 capture performance. At 1 bar, high CO2 uptake of 4.02 and 6.35 mmol g-1 at 25 and 0 °C was achieved for the sample NPC-2 with a molar ratio of F127 : urea = 0.010 : 1. This can be attributed to its well-developed micropore structure and abundant pyridinic nitrogen, pyrrolic nitrogen and pyridonic nitrogen functionalities. The sample NPC-2 also exhibits a remarkable selectivity for CO2/N2 separation and a fast adsorption/desorption rate and can be easily regenerated. This suggests that the polybenzoxazine-based NPCs are desirable for CO2 capture because of possessing a high micropore surface area, a large micropore volume, appropriate pore size distribution, and a large number of basic nitrogen functionalities.Nitrogen-rich porous carbons (NPCs) were synthesized from 1,5-dihydroxynaphthalene, urea, and formaldehyde based on benzoxazine chemistry by a soft-templating method with KOH chemical activation. They possess high surface areas of 856.8-1257.8 m2 g-1, a large pore volume of 0.15-0.65 cm3 g-1, tunable pore structure, high nitrogen content (5.21-5.32 wt%), and high char yields. The amount of the soft-templating agent F127 has multiple influences on the textural and chemical properties of the carbons, affecting the surface area and pore structure, impacting the compositions of nitrogen species and resulting in an improvement of the

  17. Polyaniline-deposited porous carbon electrode for supercapacitor

    International Nuclear Information System (INIS)

    Chen, W.-C.; Wen, T.-C.; Teng, H.

    2003-01-01

    Electrodes for supercapacitors were fabricated by depositing polyaniline (PANI) on high surface area carbons. The chemical composition of the PANI-deposited carbon electrode was determined by X-ray photoelectron spectroscopy (XPS). Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were used to investigate the electrochemical properties of electrodes. An equivalent circuit was proposed to successfully fit the EIS data, and the significant contribution of pseudocapacitance from PANI was thus identified. A comparative analysis on the electrochemical properties of bare-carbon electrodes was also conducted under similar conditions. The performance of the capacitors equipped with the resulting electrodes in 1 M H 2 SO 4 was evaluated by constant current charge-discharge cycling within a potential range from 0 to 0.6 V. The PANI-deposited electrode exhibits high specific capacitance of 180 F/g, in comparison with a value of 92 F/g for the bare-carbon electrode

  18. Highly porous carbon with large electrochemical ion absorption capability for high-performance supercapacitors and ion capacitors

    Science.gov (United States)

    Wang, Shijie; Wang, Rutao; Zhang, Yabin; Zhang, Li

    2017-11-01

    Carbon-based supercapacitors have attracted extensive attention as the complement to batteries, owing to their durable lifespan and superiority in high-power-demand fields. However, their widespread use is limited by the low energy storage density; thus, a high-surface-area porous carbon is urgently needed. Herein, a highly porous carbon with a Brunauer-Emmett-Teller specific surface area up to 3643 m2 g-1 has been synthesized by chemical activation of papayas for the first time. This sp2-bonded porous carbon has a continuous three-dimensional network of highly curved, atom-thick walls that form narrow mesopores of 2 ˜ 5 nm in width, which can be systematically tailored with varied activation levels. Two-electrode symmetric supercapacitors constructed by this porous carbon achieve energy density of 8.1 Wh kg-1 in aqueous electrolyte and 65.5 Wh kg-1 in ionic-liquid electrolyte. Furthermore, half-cells (versus Li or Na metal) using this porous carbon as ion sorption cathodes yield high specific capacity, e.g., 51.0 and 39.3 mAh g-1 in Li+ and Na+ based organic electrolyte. These results underline the possibility of obtaining the porous carbon for high-performance carbon-based supercapacitors and ion capacitors in a readily scalable and economical way.

  19. Highly porous carbon with large electrochemical ion absorption capability for high-performance supercapacitors and ion capacitors.

    Science.gov (United States)

    Wang, Shijie; Wang, Rutao; Zhang, Yabin; Zhang, Li

    2017-11-03

    Carbon-based supercapacitors have attracted extensive attention as the complement to batteries, owing to their durable lifespan and superiority in high-power-demand fields. However, their widespread use is limited by the low energy storage density; thus, a high-surface-area porous carbon is urgently needed. Herein, a highly porous carbon with a Brunauer-Emmett-Teller specific surface area up to 3643 m 2 g -1 has been synthesized by chemical activation of papayas for the first time. This sp 2 -bonded porous carbon has a continuous three-dimensional network of highly curved, atom-thick walls that form narrow mesopores of 2 ∼ 5 nm in width, which can be systematically tailored with varied activation levels. Two-electrode symmetric supercapacitors constructed by this porous carbon achieve energy density of 8.1 Wh kg -1 in aqueous electrolyte and 65.5 Wh kg -1 in ionic-liquid electrolyte. Furthermore, half-cells (versus Li or Na metal) using this porous carbon as ion sorption cathodes yield high specific capacity, e.g., 51.0 and 39.3 mAh g -1 in Li + and Na + based organic electrolyte. These results underline the possibility of obtaining the porous carbon for high-performance carbon-based supercapacitors and ion capacitors in a readily scalable and economical way.

  20. Optimization of Preparation Program for Biomass Based Porous Active Carbon by Response Surface Methodology Based on Adsorptive Property

    Directory of Open Access Journals (Sweden)

    ZHANG Hao

    2017-06-01

    Full Text Available With waste walnut shell as raw material, biomass based porous active carbon was made by microwave oven method. The effects of microwave power, activation time and mass fraction of phosphoric acid on adsorptive property of biomass based porous active carbon in the process of physical activation of active carbon precursor were studied by response surface method and numerical simulation method, the preparation plan of biomass based porous active carbon was optimized, and the optimal biomass based porous active carbon property was characterized. The results show that three factors affect the adsorptive property of biomass based porous active carbon, but the effect of microwave power is obviously more significant than that of mass fraction of phosphoric acid, and the effect of mass fraction of phosphoric acid is more significant than that of activation time. The optimized preparation conditions are:microwave power is 746W, activation time is 11.2min and mass fraction of phosphoric acid is 85.9% in the process of physical activation of activated carbon precursor by microwave heating method. For the optimal biomass based porous active carbon, the adsorption value of iodine is 1074.57mg/g, adsorption value of methylene blue is 294.4mL/g and gain rate is 52.1%.

  1. Morphology-dependent Electrochemical Enhancements of Porous Carbon as Sensitive Determination Platform for Ascorbic Acid, Dopamine and Uric Acid

    Science.gov (United States)

    Cheng, Qin; Ji, Liudi; Wu, Kangbing; Zhang, Weikang

    2016-02-01

    Using starch as the carbon precursor and different-sized ZnO naoparticles as the hard template, a series of porous carbon materials for electrochemical sensing were prepared. Experiments of scanning electron microscopy, transmission electron microscopy and Nitrogen adsorption-desorption isotherms reveal that the particle size of ZnO has big impacts on the porous morphology and surface area of the resulting carbon materials. Through ultrasonic dispersion of porous carbon and subsequent solvent evaporation, different sensing interfaces were constructed on the surface of glassy carbon electrode (GCE). The electrochemical behaviors of ascorbic acid (AA), dopamine (DA) and uric acid (UA) were studied. On the surface of porous carbon materials, the accumulation efficiency and electron transfer ability of AA, DA and UA are improved, and consequently their oxidation signals enhance greatly. Moreover, the interface enhancement effects of porous carbon are also controlled by the particle size of hard template. The constructed porous carbon interface displays strong signal amplification ability and holds great promise in constructing a sensitive platform for the simultaneous determination of AA, DA and UA.

  2. Silica decorated on porous activated carbon nanofiber composites for high-performance supercapacitors

    Science.gov (United States)

    Kim, So Yeun; Kim, Bo-Hye

    2016-10-01

    A hybrid of silica decorated on porous activated carbon nanofibers (ACNFs) is fabricated in the form of a web via electrospinning and an activation process as an electrode material for electrochemical capacitors in an organic electrolyte. The introduction of PhSiH3 (PS) into the polyacrylonitrile (PAN) solution induces a porous ACNF structure containing silica nanoparticles (NPs) via the spontaneous sol-gel process of PS by steam in the subsequent physical activation process. These inorganic-organic hybrid composites of porous ACNF containing silica NPs show superior specific capacitance and energy density in electrochemical tests, along with good rate capability and excellent cycle life in an organic electrolyte, which is attributed to the combination of ACNF's high surface area and silica's hydrophilicity. The electrochemical performance decreases with increasing PS concentration, and this trend is consistent with the specific surface area results, which reveal the rapid formation of a double layer.

  3. Nano

    DEFF Research Database (Denmark)

    Nørgaard, Bent; Engel, Lars Romann

    2007-01-01

    Gennem de sidste par år har et lille ord med et meget stort potentiale gentagende trængt sig på i den offentlige bevidsthed, det er ordet "nano". Nanovidenskab og nanoteknologi er lige nu to af de "hotteste" forskningsområder og betragtes af mange som porten til en helt ny verden af muligheder....... Muligheder, vi endnu ikke kender konsekvenserne af. Center for Kunst og Videnskabs forestilling NANO giver dig chancen for at blive bekendt med verdens mindste byggesten og idégrundlaget for nanoforskningen. Vi har skabt et rum, som på mange måder minder om et laboratorium. Rummet er forsynet med storskærme......, kolber, væsker og nanopartikler. Her vil du f.eks. opleve, hvordan forskere tilfører guld helt nye egenskaber. Forestillingen veksler mellem kemiske arbejdsdemonstrationer, stemningsskabende musik og livlig debat på storskærme mellem eksperter. NANO opfordrer publikum til at tage stilling til forskningen...

  4. Generation of highly stable and active strong base sites on organized nano-porous alumina by calcium oxide

    Science.gov (United States)

    Tarlani, Aliakbar; Zarabadi, Mir Pouyan

    2013-02-01

    In a new approach, strong basic sites has been successfully prepared by loading of calcium nitrate (Ca) on organized nano-porous alumina (ONPA). The prepared CaONPAs were characterized by low-angle X-ray diffraction (XRD), N2 adsorption-desorption isotherms (Brunauer-Emmett-Teller (BET)-Barret-Joyner-Halenda (BJH)), transmission electron microscopy (TEM) and thermogravimetric analysis (TGA). Measuring of the amount of the basic sites and the basicity was carried out by titration method, temperature-programmed desorption (TPD-CO2) and Hammett indicators. Resistance of the basic sites was also tested by washing with water. N2 sorption measurements showed that supporting of the calcium nitrate on ONPA can lead to the bimodal porosity at lower loading. BET surface area of the bare ONPA was 212 m2/g which decreased to 111 m2/g for the 25% of loading of Ca (25CaONPA). The results pointed out that CaONPA samples have basicity between 18.4 < H_ < 22 for 15 and 25% of loadings and well-preserved of the basicity after washing with water especially for 5 and 15% samples. Also no crystalline phase of CaO was observed for 25CaONPA which was calcined at 600 °C.

  5. Development of high performance nano-porous polyethersulfone ultrafiltration membranes with hydrophilic surface and superior antifouling properties

    International Nuclear Information System (INIS)

    Rahimpour, Ahmad; Madaeni, Sayed Siavash; Jahanshahi, Mohsen; Mansourpanah, Yaghoub; Mortazavian, Narmin

    2009-01-01

    Hydrophilic nano-porous polyethersulfone ultrafiltration membranes were developed for milk concentration. The membranes were prepared from new dope solution containing polyethersulfone (PES)/polyvinylpirrolidone (PVP)/polyethyleneglycole (PEG)/cellulose acetate phthalate (CAP)/acrylic acid/Triton X-100 using phase inversion induced by immersion precipitation technique. This casting solution leads to formation of new hydrophilic membranes. The morphological studies were investigated by scanning electron microscopy (SEM) and atomic force microscopy (AFM). In addition, the hydrophilicity and performance of membranes were examined by contact angel measurements and cross-flow filtration (pure water flux, milk water permeation, protein rejection and antifouling measurements). The contact angle measurements indicate that a surface with superior hydrophilicity was obtained for PES membranes. Two concentrations of PES (16 and 14.4 wt.%) and two different non-solvents (pure water and mixtures of water and IPA) were used for preparation of membranes. The morphological studies showed that the higher concentration of PES and the presence of IPA in the gelation media results in formation of a membrane with a dense top and sub-layer with small pores on the surface. The pure water flux of membranes was decreased when higher polymer concentration and mixtures of water and IPA were employed for membrane formation. On the other hand, the milk water permeation and protein rejection were increased using mixtures of water and IPA as non-solvent. Furthermore, the fouling analysis of the membranes demonstrated that the membrane surface with fewer tendencies for fouling was obtained.

  6. Organic-inorganic hybrid polyionic liquid based polyoxometalate as nano porous material for selective oxidation of sulfides

    Science.gov (United States)

    Rafiee, Ezzat; Shahebrahimi, Shabnam

    2017-07-01

    Organic-inorganic hybrid nano porous materials based on poly(ionic liquid)-polyoxometalate (PIL-POM) were reported. These hybrid materials were synthesized by the reaction of 4-vinyl pyridine with 1,3-propanesultone, followed by the polymerization and also sulfonate-functionalized cross-linked poly(4-vinylpyridine) and combining these polymers with H5PMo10V2O40 (PMo10V2). Activity of prepared PIL-PMo10V2 hybrids were investigated as catalysts for oxidation of sulfides with H2O2 as oxidant. For understanding catalytic activities of the PIL-PMo10V2 hybrids in oxidation of sulfides, effect of catalyst composition, substrate, and reaction conditions were studied. The results show that the PIL-PMo10V2 hybrids are active as selective heterogeneous catalysts for oxidation of sulfides and can be recovered and reused. The catalyst was characterized by FT-IR, TGA-DSC, XRD, SEM/EDX, BET, CV and zeta potential measurement. Also, average molecular weight of prepared catalysts were measured.

  7. Functionalization of multilayer fullerenes (carbon nano-onions) using diazonium compounds and "click" chemistry.

    Science.gov (United States)

    Flavin, Kevin; Chaur, Manuel N; Echegoyen, Luis; Giordani, Silvia

    2010-02-19

    A novel versatile approach for the functionalization of multilayer fullerenes (carbon nano-onions) has been developed, which involves the facile introduction of a variety of simple functionalities onto their surface by treatment with in situ generated diazonium compounds. This approach is complemented by use of "click" chemistry which was used for the covalent introduction of more complex porphyrin molecules.

  8. Numerical investigation of heat transfer enhancement by carbon nano fibers deposited on a flat plate

    NARCIS (Netherlands)

    Pelevic, Nikola; van der Meer, Theo

    2013-01-01

    Numerical simulations of flow and heat transfer have been performed for flow over a plate surface covered with carbon nano fibers (CNFs). The CNFs influence on fluid flow and heat transfer has been investigated. Firstly, a stochastic model for CNFs deposition has been explained. Secondly, the

  9. Properties of the chalcogenide–carbon nano tubes and graphene composite materials

    International Nuclear Information System (INIS)

    Singh, Abhay Kumar; Kim, JunHo; Park, Jong Tae; Sangunni, K.S.

    2015-01-01

    Highlights: • Chalcogenides. • Melt quenched. • Composite materials. • Multi walled carbon nano tubes. • Bilayer graphene. - Abstract: Composite can deliver more than the individual elemental property of the material. Specifically chalcogenide- multi walled carbon nano tubes and chalcogenide- bilayer graphene composite materials could be interesting for the investigation, which have been less covered by the investigators. We describe micro structural properties of Se 55 Te 25 Ge 20, Se 55 Te 25 Ge 20 + 0.025% multi walled carbon nano tubes and Se 55 Te 25 Ge 20 + 0.025% bilayer graphene materials. This gives realization of the alloying constituents inclusion/or diffusion inside the multi walled carbon nano tubes and bilayer graphene under the homogeneous parent alloy configuration. Raman spectroscopy, X-ray photoelectron spectroscopy, UV/Visible spectroscopy and Fourier transmission infrared spectroscopy have also been carried out under the discussion. A considerable core energy levels peak shifts have been noticed for the composite materials by the X-ray photoelectron spectroscopy. The optical energy band gaps are measured to be varied in between 1.2 and 1.3 eV. In comparison to parent (Se 55 Te 25 Ge 20 ) alloy a higher infrared transmission has been observed for the composite materials. Subsequently, variation in physical properties has been explained on the basis of bond formation in solids

  10. Sensitization of nano-porous ZnO photo-anode by a conjugated conducting polymer

    Energy Technology Data Exchange (ETDEWEB)

    Sirimanne, P.M. [Nano-Science Laboratory, Institute of Fundamental Studies, Hantana Road, Kandy (Sri Lanka); Environmental and Renewable Energy Systems Division, Graduate School of Engineering, Gifu University, 1-1 Yanagido, Gifu 501-1193 (Japan); Premalal, E.V.A. [Nano-Science Laboratory, Institute of Fundamental Studies, Hantana Road, Kandy (Sri Lanka); Minoura, H. [Environmental and Renewable Energy Systems Division, Graduate School of Engineering, Gifu University, 1-1 Yanagido, Gifu 501-1193 (Japan)

    2011-01-15

    Hybrid ZnO films are prepared via one-step electrochemical process. Extraction of organic component from hybrid films results tiny wires like ZnO columns perpendicular to the substrate. Visible light sensitive-conjugated polymer poly(2-methoxy-5-[2 ethylhexyloxy]-1-4-phenylenevinylene, MEH-PPV) was embedded in highly porous ZnO ceramic by a solvent vaporization technique. An attempt was made to fabricate polymer sensitized photovoltaic cell by coupling polymer embedded ZnO electrodes with an electrolyte. Maximum photovoltage of 490 mV is observed for the cell with the configuration of ZnO vertical stroke MEH-PPV vertical stroke I{sup -}/I{sub 3}{sup -} cell. (author)

  11. Hydrogen production from nano-porous Si powder formed by stain etching

    Energy Technology Data Exchange (ETDEWEB)

    Litvinenko, S.; Alekseev, S.; Kuznetsov, G.; Skryshevsky, V. [Institute of High Technology of National Taras Shevchenko University of Kyiv, Volodymyrs' ka 64, Kyiv 01601 (Ukraine); Lysenko, V.; Barbier, D. [Lyon Institute of Nanotechnologies (INL), CNRS UMR-5270, University of Lyon, INSA de Lyon, 7 avenue Jean Capelle, Bat. Blaise Pascal, 69621 Villeurbanne Cedex (France); Venturello, A.; Geobaldo, F.; Garrone, E. [Politecnico di Torino, Department of Materials Science and Chemical Engineering, 10129 Torino (Italy); Gulina, L.; Tolstoy, V. [St-Petersburg State University, Chemical Department (Russian Federation)

    2010-07-15

    Hydrogen reservoirs based on porous silicon (PS) nanostructures are considered. Silicon-based hydrogen tanks are believed to be applicable for portable device energy supply and compatible with micro-sources of energy of new generation. Stain etching of silicon powder to produce PS is studied as a technology alternative to conventional electrochemical etching and application of the PS powder for hydrogen production is also described. Size selection of initial Si micro-particles constituting the powders was carried out by sedimentation technique. Hydrogen content in PS was investigated by FTIR spectroscopy. Extraction of hydrogen in water environment in presence of small amount of NH{sub 3} as catalyst was shown to have advantages such as safety and tunability, additional production of hydrogen from water dissociation, and a possibility to characterize PS as a hydrogen source material in terms of hydrogen effective shell and crystalline core conception. (author)

  12. Investigation of Single Phase NanoCellulose Transport through Porous Media

    Science.gov (United States)

    Dziuba, Carter Jordan

    The application of nanotechnology to the petroleum industry has seen many recent advancements. Nanocellulose is an emerging nanoparticle at the forefront of research. Before nanocellulose can be injected into petroleum reservoirs, further understanding is needed as to the retention mechanisms that occur during nanocellulose transport through porous media. A series of unconsolidated sandpack floods were preformed with nanocellulose and the resulting retention and permeability reduction were measured. The experimental variables include nanocellulose type, sand grain size, flowrate, and salinity. It was found that all types of nanocellulose tested showed significantly different transport properties. Retention and permeability reduction increased as grain size decreased or flowrate decreased. As a general trend, the larger the size of aggregates in bulk solution, the greater the retention and permeability reduction. Salinity was found to be the primary parameter affecting transport. Increased salinity caused additional aggregation which resulted in increased straining and filter cake formation.

  13. Porous Silicon–Carbon Composite Materials Engineered by Simultaneous Alkaline Etching for High-Capacity Lithium Storage Anodes

    International Nuclear Information System (INIS)

    Sohn, Myungbeom; Kim, Dae Sik; Park, Hyeong-Il; Kim, Jae-Hun; Kim, Hansu

    2016-01-01

    Highlights: • A porous Si–C anode is obtained by alkaline etching of a non-porous Si–C composite. • The pores in the carbon frame are created by simultaneous etching of Si and carbon. • The cycle life is greatly improved after the alkaline treatment. • The porous Si–C composite electrode shows high dimensional stability during cycling. - Abstract: Porous silicon–carbon (Si–C) composite materials have attracted a great deal of attention as high-performance anode materials for Li-ion batteries (LIBs), but their use suffers from the complex and limited synthetic routes for their preparation. Herein we demonstrate a scalable and nontoxic method to synthesize porous Si–C composite materials by means of simultaneous chemical etching of Si and carbon phases using alkaline solution. The resulting porous Si–C composite material showed greatly improved cycle performance, good rate capability, and high dimensional stability during cycling. Porous Si–C electrode showed an expansion of the height by about 22% after the first lithiation and only 16% after the first cycle. The material synthesis concept and scalable simultaneous etching approach presented here represent a means of improving the electrochemical properties of Si-based porous anode materials for use in commercial LIBs.

  14. A porous carbon material from pyrolysis of fructus cannabis’s shells for supercapacitor electrode application

    Science.gov (United States)

    Li, Kai; Zhang, Wei-Bin; Zhao, Zhi-Yun; Zhao, Yue; Chen, Xi-Wen; Kong, Ling-Bin

    2018-02-01

    The porous carbon material is obtained via pyrolysis and activation of fructus cannabis’s shells, an easy-to-get biomass source, and is used as an active electrode material for supercapacitors. The obtained carbon exhibit a high specific surface area of 2389 m2 g-1. And the result of x-ray photoelectron spectroscopy (XPS) shows that the obtained porous carbon possess numerous oxygen groups, which can facilitate the wettability of the electrode. The prepared porous carbon also exhibit remarkable electrochemical properties, such as high specific capacitance of 357 F g-1 at a current density of 0.5 A g-1 in 6 mol L-1 aqueous KOH electrolyte, good rate capability of 77% capacitance retention as the current density increase from 0.5 A g-1 to 10 A g-1. In addition, it also presents a superior cycling stability of 100% capacitance retention after 10 000 cycles at the current density of 1 A g-1.

  15. Hierarchical porous nitrogen-doped partial graphitized carbon monoliths for supercapacitor

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Yifeng; Du, Juan; Liu, Lei; Wang, Guoxu; Zhang, Hongliang; Chen, Aibing, E-mail: chen-ab@163.com [Hebei University of Science and Technology, College of Chemical and Pharmaceutical Engineering (China)

    2017-03-15

    Porous carbon monoliths have attracted great interest in many fields due to their easy availability, large specific surface area, desirable electronic conductivity, and tunable pore structure. In this work, hierarchical porous nitrogen-doped partial graphitized carbon monoliths (N–MC–Fe) with ordered mesoporous have been successfully synthesized by using resorcinol-formaldehyde as precursors, iron salts as catalyst, and mixed triblock copolymers as templates via a one-step hydrothermal method. In the reactant system, hexamethylenetetramine (HMT) is used as nitrogen source and one of the carbon precursors under hydrothermal conditions instead of using toxic formaldehyde. The N–MC–Fe show hierarchically porous structures, with interconnected macroporous and ordered hexagonally arranged mesoporous. Nitrogen element is in situ doped into carbon through decomposition of HMT. Iron catalyst is helpful to improve the graphitization degree and pore volume of N–MC–Fe. The synthesis strategy is user-friendly, cost-effective, and can be easily scaled up for production. As supercapacitors, the N–MC–Fe show good capacity with high specific capacitance and good electrochemical stability.

  16. Preparation and characterization of hierarchical porous carbons derived from solid leather waste for supercapacitor applications

    International Nuclear Information System (INIS)

    Konikkara, Niketha; Kennedy, L. John; Vijaya, J. Judith

    2016-01-01

    Highlights: • Solid leather waste was used as a precursor for preparing HPCs—waste to energy storage. • The textural, structural and morphological properties show the hierarchical porous nature. • Porous carbon with surface area 716 m"2/g and pore volume 0.4030 cm"3/g has been produced. • HPCs based supercapacitor electrodes are fabricated with three electrode system in 1 M KCl. • Specific capacitance of 1960 F/g is achieved at scan rate of 1 mV/s in 1 M KCl. - Abstract: Utilization of crust leather waste (CLW) as precursors for the preparation of hierarchical porous carbons (HPC) were investigated. HPCs were prepared from CLW by pre-carbonization followed by chemical activation using KOH at relatively high temperatures. Textural properties of HPC’s showed an extent of micro-and mesoporosity with maximum BET surface area of 716 m"2/g. Inducements of graphitic planes in leather waste derived carbons were observed from X-ray diffraction and HR-TEM analysis. Microstructure, thermal behavior and surface functional groups were identified using FT-Raman, thermo gravimetric analysis and FT-IR techniques. HPCs were evaluated for electrochemical properties by cyclic voltammetry (CV), galvanostatic charge/discharge (GCD) and electrochemical impedance spectroscopy (EIS) by three electrode system. CLC9 sample showed a maximum capacitance of 1960 F/g in 1 M KCl electrolyte. Results achieved from rectangular curves of CV, GCD symmetric curves and Nyquist plots show that the leather waste carbon is suitable to fabricate supercapacitors as it possess high specific capacitance and electrochemical cycle stability. The present study proposes an effective method for solid waste management in leather industry by the way of converting toxic leather waste to new graphitic porous carbonaceous materials as a potential candidate for energy storage devices.

  17. Preparation and characterization of hierarchical porous carbons derived from solid leather waste for supercapacitor applications

    Energy Technology Data Exchange (ETDEWEB)

    Konikkara, Niketha [Materials Division, School of Advanced Sciences, Vellore Institute of Technology (VIT) University, Chennai Campus, Chennai 600 127 (India); Kennedy, L. John, E-mail: jklsac14@yahoo.co.in [Materials Division, School of Advanced Sciences, Vellore Institute of Technology (VIT) University, Chennai Campus, Chennai 600 127 (India); Vijaya, J. Judith [Catalysis and Nanomaterials Research Laboratory, Department of Chemistry, Loyola College (Autonomous) Chennai 600 034 (India)

    2016-11-15

    Highlights: • Solid leather waste was used as a precursor for preparing HPCs—waste to energy storage. • The textural, structural and morphological properties show the hierarchical porous nature. • Porous carbon with surface area 716 m{sup 2}/g and pore volume 0.4030 cm{sup 3}/g has been produced. • HPCs based supercapacitor electrodes are fabricated with three electrode system in 1 M KCl. • Specific capacitance of 1960 F/g is achieved at scan rate of 1 mV/s in 1 M KCl. - Abstract: Utilization of crust leather waste (CLW) as precursors for the preparation of hierarchical porous carbons (HPC) were investigated. HPCs were prepared from CLW by pre-carbonization followed by chemical activation using KOH at relatively high temperatures. Textural properties of HPC’s showed an extent of micro-and mesoporosity with maximum BET surface area of 716 m{sup 2}/g. Inducements of graphitic planes in leather waste derived carbons were observed from X-ray diffraction and HR-TEM analysis. Microstructure, thermal behavior and surface functional groups were identified using FT-Raman, thermo gravimetric analysis and FT-IR techniques. HPCs were evaluated for electrochemical properties by cyclic voltammetry (CV), galvanostatic charge/discharge (GCD) and electrochemical impedance spectroscopy (EIS) by three electrode system. CLC9 sample showed a maximum capacitance of 1960 F/g in 1 M KCl electrolyte. Results achieved from rectangular curves of CV, GCD symmetric curves and Nyquist plots show that the leather waste carbon is suitable to fabricate supercapacitors as it possess high specific capacitance and electrochemical cycle stability. The present study proposes an effective method for solid waste management in leather industry by the way of converting toxic leather waste to new graphitic porous carbonaceous materials as a potential candidate for energy storage devices.

  18. Enhancement of osteogenesis on micro/nano-topographical carbon fiber-reinforced polyetheretherketone–nanohydroxyapatite biocomposite

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Anxiu [College of Stomatology, Chongqing Medical University, Chongqing 401147 (China); Chongqing Key Laboratory of Oral Diseases and Biomedical Sciences, Chongqing Medical University, Chongqing 401147 (China); Liu, Xiaochen [Center for Biomedical Materials and Tissue Engineering, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871 (China); Gao, Xiang; Deng, Feng [College of Stomatology, Chongqing Medical University, Chongqing 401147 (China); Chongqing Key Laboratory of Oral Diseases and Biomedical Sciences, Chongqing Medical University, Chongqing 401147 (China); Deng, Yi, E-mail: 18210357357@163.com [College of Stomatology, Chongqing Medical University, Chongqing 401147 (China); Chongqing Key Laboratory of Oral Diseases and Biomedical Sciences, Chongqing Medical University, Chongqing 401147 (China); Wei, Shicheng, E-mail: weishicheng99@163.com [College of Stomatology, Chongqing Medical University, Chongqing 401147 (China); Chongqing Key Laboratory of Oral Diseases and Biomedical Sciences, Chongqing Medical University, Chongqing 401147 (China)

    2015-03-01

    As an FDA-approved implantable material, carbon fiber-reinforced polyetheretherketone (CFRPEEK) possesses excellent mechanical properties similar to those of human cortical bone and is a prime candidate to replace conventional metallic implants. The bioinertness and inferior osteogenic properties of CFRPEEK, however, limit its clinical application as orthopedic/dental implants. The present work aimed at developing a novel carbon fiber-reinforced polyetheretherketone–nanohydroxyapatite (PEEK/CF/n-HA) ternary biocomposite with micro/nano-topographical surface for the enhancement of the osteogenesis as a potential bioactive material for bone grafting and bone tissue-engineering applications. The combined modification of oxygen plasma and sand-blasting could improve the hydrophily and generate micro/nano-topographical structures on the surface of the CFRPEEK-based ternary biocomposite. The results clearly showcased that the micro-/nano-topographical PEEK/n-HA/CF ternary biocomposite demonstrated the outstanding ability to promote the proliferation and differentiation of MG-63 cells in vitro as well as to boost the osseointegration between implant and bone in vivo, thereby boding well application to bone tissue engineering. - Highlights: • A novel micro/nano-topographical PEEK/n-HA/CF ternary biocomposite was developed. • The modified PEEK biocomposite promotes proliferation and differentiation of cells. • In vivo osseointegration of the micro/nano-topographical PEEK/n-HA/CF was enhanced.

  19. Enhancement of osteogenesis on micro/nano-topographical carbon fiber-reinforced polyetheretherketone–nanohydroxyapatite biocomposite

    International Nuclear Information System (INIS)

    Xu, Anxiu; Liu, Xiaochen; Gao, Xiang; Deng, Feng; Deng, Yi; Wei, Shicheng

    2015-01-01

    As an FDA-approved implantable material, carbon fiber-reinforced polyetheretherketone (CFRPEEK) possesses excellent mechanical properties similar to those of human cortical bone and is a prime candidate to replace conventional metallic implants. The bioinertness and inferior osteogenic properties of CFRPEEK, however, limit its clinical application as orthopedic/dental implants. The present work aimed at developing a novel carbon fiber-reinforced polyetheretherketone–nanohydroxyapatite (PEEK/CF/n-HA) ternary biocomposite with micro/nano-topographical surface for the enhancement of the osteogenesis as a potential bioactive material for bone grafting and bone tissue-engineering applications. The combined modification of oxygen plasma and sand-blasting could improve the hydrophily and generate micro/nano-topographical structures on the surface of the CFRPEEK-based ternary biocomposite. The results clearly showcased that the micro-/nano-topographical PEEK/n-HA/CF ternary biocomposite demonstrated the outstanding ability to promote the proliferation and differentiation of MG-63 cells in vitro as well as to boost the osseointegration between implant and bone in vivo, thereby boding well application to bone tissue engineering. - Highlights: • A novel micro/nano-topographical PEEK/n-HA/CF ternary biocomposite was developed. • The modified PEEK biocomposite promotes proliferation and differentiation of cells. • In vivo osseointegration of the micro/nano-topographical PEEK/n-HA/CF was enhanced

  20. A novel and facile synthesis approach for a porous carbon/graphene composite for high-performance supercapacitors.

    Science.gov (United States)

    Liu, Ting; Zhang, Xuesha; Liu, Kang; Liu, Yanyan; Liu, Mengjie; Wu, Wenyu; Gu, Yu; Zhang, Ruijun

    2018-03-02

    We propose a novel and facile synthesis approach to a porous carbon/graphene composite. Graphene is obtained from room-temperature expanded graphite (RTEG), not involving the use of graphite oxide (GO). Porous carbon is acquired by carbonization and KOH-activation of polyvinylpyrrolidone (PVP), which is used to exfoliate RTEG into graphene and inhibit the restacking of the resultant graphene in the present work. The prepared porous carbon/graphene composite has a high specific surface area (SSA) (3008 m 2 g -1 ) and a hierarchical micro- and meso- pore structure (dominant pores in the range of 1-5 nm). Electrochemical measurement demonstrates that the as-prepared porous carbon/graphene composite can deliver an outstanding specific capacitance of up to 340 F g -1 at 5 mV s -1 in 6 M KOH electrolyte. This specific capacitance is among the highest reported so far for porous carbon/graphene materials. Moreover, the prepared composite as an electrode material also exhibits excellent cycling stability (94.4% capacitance retention over 10 000 cycles). The as-fabricated symmetrical supercapacitor exhibits a high energy density of 10.9 W h kg -1 (based on total mass of electrode materials) and an outstanding energy density retention, even at high power density. Compared with conventional preparation routes for porous carbon/graphene composites, the present approach is significantly simple, convenient and cost-effective, which will make it more competent in the development of electrode materials for high-performance supercapacitors.

  1. Study on purification of carbon nano tubes grown on Fe/Ni bimetallic catalyst supported on Mg O by thermal chemical vapor deposition

    International Nuclear Information System (INIS)

    Mirershadi, S.; Mortazavi, Z.; Reyhani, A.; Norouzian, Sh.; Moniri, N.; Novinrooz, A. J.

    2007-01-01

    Carbon nano tubes grown on Fe/Ni bimetallic catalysts supported on Mg O by thermal chemical vapor deposition. Then purification of carbon nano tubes by oxidation under air at atmospheric pressure and acid treatment with HCl, have been studied. The Scanning electron microscopy observation showed impurities with carbon nano tubes. Scanning electron microscopy, XRD, Raman spectroscopy and Thermogravimetric analysis/Differential Scanning Calorimetry techniques have been used to investigate the effect of purification of carbon nano tubes on morphology and structural quality of them. The weight ratio of carbon nano tubes in purified sample re saved to 85/8 %.

  2. Cauliflower-derived porous carbon without activation for electrochemical capacitor and CO2 capture applications

    Science.gov (United States)

    Du, Juan; Yu, Yifeng; Lv, Haijun; Chen, Chunlin; Zhang, Jian; Chen, Aibing

    2018-01-01

    Carbon materials have attracted great attention in CO2 capture and energy storage due to their excellent characteristics such as tunable pore structure, modulated surface properties and superior bulk conductivities, etc. Biomass, provided by nature with non-toxic, widespread, abundant, and sustainable advantages, is considered to be a very promising precursor of carbons for the view of economic, environmental, and societal issues. However, the preparation of high-performance biomass-derived carbons is still a big challenge because of the multistep process for their synthesis and subsequent activation. Herein, hierarchically porous structured carbon materials have been prepared by directly carbonizing dried cauliflowers without any addition of agents and activation process, featuring with large specific surface area, hierarchically porous structure and improved pore volume, as well as suitable nitrogen content. Being used as a solid-state CO2 adsorbent, the obtained product exhibited a high CO2 adsorption capacity of 3.1 mmol g-1 under 1 bar and 25 °C and a remarkable reusability of 96.7% retention after 20 adsorption/regeneration cycles. Our study reveals that choosing a good biomass source was significant as the unique structure of precursor endows the carbonized product with abundant pores without the need of any post-treatment. Used as an electrode material in electrochemical capacitor, the non-activated porous carbon displayed a fairly high specific capacitance of 228.9 F g-1 at 0.5 A g-1 and an outstanding stability of 99.2% retention after 5000 cycles at 5 A g-1. [Figure not available: see fulltext.

  3. Improving carbon tolerance of Ni-YSZ catalytic porous membrane by palladium addition for low temperature steam methane reforming

    Science.gov (United States)

    Lee, Sang Moon; Won, Jong Min; Kim, Geo Jong; Lee, Seung Hyun; Kim, Sung Su; Hong, Sung Chang

    2017-10-01

    Palladium was added on the Ni-YSZ catalytic porous membrane by wet impregnation and electroless plating methods. Its surface morphology characteristics and carbon deposition properties for the low temperature steam methane reforming were investigated. The addition of palladium could obviously be enhanced the catalytic activity as well as carbon tolerance of the Ni-YSZ porous membrane. The porous membranes were evaluated by scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), H2 temperature-programmed reduction (H2-TPR), CH4 temperature-programmed reduction (CH4-TPR), and O2 temperature-programmed oxidation (O2-TPO). It was found that the Pd-Ni-YSZ catalytic porous membrane showed the superior stability as well as the deposition of carbon on the surface during carbon dissociation adsorption at 650 °C was also suppressed.

  4. Three-Dimensional Porous Particles Composed of Curved, Two-Dimensional, Nano-Sized Layers for Li-Ion Batteries

    Science.gov (United States)

    Yushin, Gleb; Evanoff, Kara; Magasinski, Alexander

    2012-01-01

    Thin Si films coated on porous 3D particles composed of curved 2D graphene sheets have been synthesized utilizing techniques that allow for tunable properties. Since graphene exhibits specific surface area up to 100 times higher than carbon black or graphite, the deposition of the same mass of Si on graphene is much faster in comparison -- a factor which is important for practical applications. In addition, the distance between graphene layers is tunable and variation in the thickness of the deposited Si film is feasible. Both of these characteristics allow for optimization of the energy and power characteristics. Thicker films will allow higher capacity, but slower rate capabilities. Thinner films will allow more rapid charging, or higher power performance. In this innovation, uniform deposition of Si and C layers on high-surface area graphene produced granules with specific surface area (SSA) of 5 sq. m/g.

  5. Nitrogen-doped porous carbon from Camellia oleifera shells with enhanced electrochemical performance

    International Nuclear Information System (INIS)

    Zhai, Yunbo; Xu, Bibo; Zhu, Yun; Qing, Renpeng; Peng, Chuan; Wang, Tengfei; Li, Caiting; Zeng, Guangming

    2016-01-01

    Nitrogen doped porous activated carbon was prepared by annealing treatment of Camellia oleifera shell activated carbon under NH 3 . We found that nitrogen content of activated carbon up to 10.43 at.% when annealed in NH 3 at 800 °C. At 600 °C or above, the N-doped carbon further reacts with NH 3 , leads to a low surface area down to 458 m 2 /g and low graphitization degree. X-ray photoelectron spectroscope (XPS) analysis indicated that the nitrogen functional groups on the nitrogen-doped activated carbons (NACs) were mostly in the form of pyridinic nitrogen. We discovered that the oxygen groups and carbon atoms at the defect and edge sites of graphene play an important role in the reaction, leading to nitrogen atoms incorporated into the lattice of carbon. When temperatures were lower than 600 °C the nitrogen atoms displaced oxygen groups and formed nitrogen function groups, and when temperatures were higher than 600 °C and ~ 4 at.% carbon atoms and part of oxygen function groups reacted with NH 3 . When compared to pure activated carbon, the nitrogen doped activated carbon shows nearly four times the capacitance (191 vs 51 F/g). - Highlights: • The nitrogen content up to 10.43 at % during CAC pyrolysis under NH3 at 800 °C. • The oxygen groups and carbon atoms played an important role in the nitrogen doping. • NAC-600 shows a much higher specific capacitance than CAC.

  6. Carbon molecular sieve membranes prepared from porous fiber precursor

    NARCIS (Netherlands)

    Barsema, J.N.; van der Vegt, N.F.A.; Koops, G.H.; Wessling, Matthias

    2002-01-01

    Carbon molecular sieve (CMS) membranes are usually prepared from dense polymeric precursors that already show intrinsic gas separation properties. The rationale behind this approach is that the occurrence of any kind of initial porosity will deteriorate the final CMS performance. We will show that

  7. In situ one-step synthesis of hierarchical nitrogen-doped porous carbon for high-performance supercapacitors.

    Science.gov (United States)

    Jeon, Ju-Won; Sharma, Ronish; Meduri, Praveen; Arey, Bruce W; Schaef, Herbert T; Lutkenhaus, Jodie L; Lemmon, John P; Thallapally, Praveen K; Nandasiri, Manjula I; McGrail, Benard Peter; Nune, Satish K

    2014-05-28

    A hierarchically structured nitrogen-doped porous carbon is prepared from a nitrogen-containing isoreticular metal-organic framework (IRMOF-3) using a self-sacrificial templating method. IRMOF-3 itself provides the carbon and nitrogen content as well as the porous structure. For high carbonization temperatures (950 °C), the carbonized MOF required no further purification steps, thus eliminating the need for solvents or acid. Nitrogen content and surface area are easily controlled by the carbonization temperature. The nitrogen content decreases from 7 to 3.3 at % as carbonization temperature increases from 600 to 950 °C. There is a distinct trade-off between nitrogen content, porosity, and defects in the carbon structure. Carbonized IRMOFs are evaluated as supercapacitor electrodes. For a carbonization temperature of 950 °C, the nitrogen-doped porous carbon has an exceptionally high capacitance of 239 F g(-1). In comparison, an analogous nitrogen-free carbon bears a low capacitance of 24 F g(-1), demonstrating the importance of nitrogen dopants in the charge storage process. The route is scalable in that multi-gram quantities of nitrogen-doped porous carbons are easily produced.

  8. Porous carbon nanosheets from coal tar for high-performance supercapacitors

    Science.gov (United States)

    He, Xiaojun; Ma, Hao; Wang, Jingxian; Xie, Yuanyang; Xiao, Nan; Qiu, Jieshan

    2017-07-01

    A hydroxide-template strategy coupled with in-situ chemical activation is reported for the first time to fabricate porous carbon nanosheets (PCNSs) from coal tar. The thin PCNSs feature abundant short pores accessible for fast ion transport and high specific surface area up to 3235 m2 g-1 for ion adsorption. As electrodes for supercapacitors, the PCNSs show a high capacitance of 296.2 F g-1 at 0.05 A g-1 in 6 M KOH electrolyte, an excellent rate performance with a capacitance of 220.7 F g-1 at 20 A g-1 and a superior cycle stability with over 97.2% capacitance retention after 11000 charge-discharge cycles at 3.5 A g-1. This work paves a new way for efficient fabrication of sheet-like carbon materials with tuned porous structure from polycyclic aromatic hydrocarbons for high performance supercapacitors.

  9. Amorphous Red Phosphorus Embedded in Sandwiched Porous Carbon Enabling Superior Sodium Storage Performances.

    Science.gov (United States)

    Wu, Ying; Liu, Zheng; Zhong, Xiongwu; Cheng, Xiaolong; Fan, Zhuangjun; Yu, Yan

    2018-03-01

    The red P anode for sodium ion batteries has attracted great attention recently due to the high theoretical capacity, but the poor intrinsic electronic conductivity and large volume expansion restrain its widespread applications. Herein, the red P is successfully encapsulated into the cube shaped sandwich-like interconnected porous carbon building (denoted as P@C-GO/MOF-5) via the vaporization-condensation method. Superior cycling stability (high capacity retention of about 93% at 2 A g -1 after 100 cycles) and excellent rate performance (502 mAh g -1 at 10 A g -1 ) can be obtained for the P@C-GO/MOF-5 electrode. The superior electrochemical performance can be ascribed to the successful incorporation of red P into the unique carbon matrix with large surface area and pore volume, interconnected porous structure, excellent electronic conductivity and superior structural stability. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Report on Carbon Nano Material Workshop: Challenges and Opportunities

    Science.gov (United States)

    2013-01-22

    trolyte fuel cells ( PEMFCs ) utilize the ability of the catalysts to initiate and maintain the oxygen reduction reaction on the cathode and the fuel...oxidation reaction on the anode. In order to increase the efficiency of the PEMFC catalysts, high-surface-area mesoporous carbons, carbon blacks, carbon...mechanical and thermal properties derived from a three-dimensional intercon- nected nanonetwork structure. The exceptional properties of CAs for PEMFC

  11. Microwave plasma CVD of NANO structured tin/carbon composites

    Science.gov (United States)

    Marcinek, Marek [Warszawa, PL; Kostecki, Robert [Lafayette, CA

    2012-07-17

    A method for forming a graphitic tin-carbon composite at low temperatures is described. The method involves using microwave radiation to produce a neutral gas plasma in a reactor cell. At least one organo tin precursor material in the reactor cell forms a tin-carbon film on a supporting substrate disposed in the cell under influence of the plasma. The three dimensional carbon matrix material with embedded tin nanoparticles can be used as an electrode in lithium-ion batteries.

  12. Porous structure evolution of cellulose carbon fibres during heating in the initial activation stage

    Energy Technology Data Exchange (ETDEWEB)

    Babel, Krzysztof [Institute of Chemical Wood Technology, Agricultural Academy of Poznan, Ul. Wojska Polskiego 38/42, 60-637 Poznan (Poland)

    2004-01-15

    This paper is focused on the description of changes in the porous structure during fast heating to the activation temperature of the viscose fibres, pyrolysed to different final temperatures. Standard regenerated cellulose fibre structures were tested. Fabrics were subjected to pyrolysis, the samples being heated to final temperatures of 400, 600 and 850 C. Carbon fibres were subsequently heated to activation temperature (850 C) at a rate of 100 C/min, and then the samples were cooled down. The characteristics of obtained carbon preparations were examined. We have defined a level of restructuring and internal ordering of fibres which originated during slow pyrolysis as well as the range of temperature differences of pyrolysis and activation where fast increase of carbon fibre temperature before activation is advantageous for the development of porous structure. It allows for partial release of pores and fast rebuilding of structure accompanied by a considerable number of defects in the carbon matrix with higher reactivity to oxidiser which, in turn, promotes the development of pores in active carbon during oxidation. Temperature difference for viscose carbon fibres is approximately 150-300 C at pyrolysis temperature of 550-700 C.

  13. Three-dimensional interconnected porous graphitic carbon derived from rice straw for high performance supercapacitors

    Science.gov (United States)

    Jin, Hong; Hu, Jingpeng; Wu, Shichao; Wang, Xiaolan; Zhang, Hui; Xu, Hui; Lian, Kun

    2018-04-01

    Three-dimensional interconnected porous graphitic carbon materials are synthesized via a combination of graphitization and activation process with rice straw as the carbon source. The physicochemical properties of the three-dimensional interconnected porous graphitic carbon materials are characterized by Nitrogen adsorption/desorption, Fourier-transform infrared spectroscopy, X-ray diffraction, Raman spectroscopy, Scanning electron microscopy and Transmission electron microscopy. The results demonstrate that the as-prepared carbon is a high surface area carbon material (a specific surface area of 3333 m2 g-1 with abundant mesoporous and microporous structures). And it exhibits superb performance in symmetric double layer capacitors with a high specific capacitance of 400 F g-1 at a current density of 0.1 A g-1, good rate performance with 312 F g-1 under a current density of 5 A g-1 and favorable cycle stability with 6.4% loss after 10000 cycles at a current density of 5 A g-1 in the aqueous electrolyte of 6M KOH. Thus, rice straw is a promising carbon source for fabricating inexpensive, sustainable and high performance supercapacitors' electrode materials.

  14. Nitrogen-doped porous carbon derived from biomass waste for high-performance supercapacitor.

    Science.gov (United States)

    Ma, Guofu; Yang, Qian; Sun, Kanjun; Peng, Hui; Ran, Feitian; Zhao, Xiaolong; Lei, Ziqiang

    2015-12-01

    High capacitance property and low cost are the pivotal requirements for practical application of supercapacitor. In this paper, a low cost and high capacitance property nitrogen-doped porous carbon with high specific capacitance is prepared. The as-prepared nitrogen-doped porous carbon employing potato waste residue (PWR) as the carbon source, zinc chloride (ZnCl2) as the activating agent and melamine as nitrogen doping agent. The morphology and structure of the carbon materials are studied by scanning electron microscopy (SEM), N2 adsorption/desorption, X-ray diffraction (XRD) and Raman spectra. The surface area of the nitrogen-doped carbon which prepared under 700°C is found to be 1052m(2)/g, and the specific capacitance as high as 255Fg(-1) in 2M KOH electrolyte is obtained utilize the carbon as electrode materials. The electrode materials also show excellent cyclability with 93.7% coulombic efficiency at 5Ag(-1) current density of for 5000cycles. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. Hydrogen storage in carbon nano-materials. Elaboration, characterization and properties

    International Nuclear Information System (INIS)

    Luxembourg, D.

    2004-10-01

    This work deals with hydrogen storage for supplying fuel cells. Hydrogen storage by adsorption in carbon nano-tubes and nano-fibers is a very controversial issue because experimental results are very dispersed and adsorption mechanisms are not yet elucidated. Physi-sorption cannot explain in fact all the experimental results. All the potential adsorption sites, physical and chemical, are discussed as detailed as possible in a state of the art. Experimental works includes the steps of elaboration, characterization, and measurements of the hydrogen storage properties. Nano-fibers are grown using a CVD approach. Single wall carbon nano-tubes (SWNT) synthesis is based on the vaporization/condensation of a carbon/catalysts mixture in a reactor using a fraction of the available concentrated solar energy at the focus of the 1000 kW solar facility of IMP-CNRS at Odeillo. Several samples are produced using different synthesis catalysts (Ni, Co, Y, Ce). SWNT samples are purified using oxidative and acid treatments. Hydrogen storage properties of these materials are carefully investigated using a volumetric technique. The applied pressure is up to 6 MPa and the temperature is 253 K. Hydrogen uptake of the investigated materials are less than 1 % wt. at 253 K and 6 MPa. (author)

  16. Three-Dimensional Porous Architectures of Carbon Nanotubes and Graphene Sheets for Energy Applications

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xuewan; Sun, Gengzhi; Chen, Peng, E-mail: chenpeng@ntu.edu.sg [Division of Bioengineering, School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore (Singapore)

    2014-08-20

    Owing to their extraordinary physicochemical, electrical, and mechanical properties, carbon nanotubes (CNTs) and graphene materials have been widely used to improve energy storage and conversion. In this article, we briefly review the latest development on fabrication of 3D porous structures of CNTs or graphene sheets or their hybrids, and their applications in various energy devices including supercapacitors, (bio-) fuel cells, and lithium ion batteries.

  17. Three-Dimensional Porous Architectures of Carbon Nanotubes and Graphene Sheets for Energy Applications

    International Nuclear Information System (INIS)

    Wang, Xuewan; Sun, Gengzhi; Chen, Peng

    2014-01-01

    Owing to their extraordinary physicochemical, electrical, and mechanical properties, carbon nanotubes (CNTs) and graphene materials have been widely used to improve energy storage and conversion. In this article, we briefly review the latest development on fabrication of 3D porous structures of CNTs or graphene sheets or their hybrids, and their applications in various energy devices including supercapacitors, (bio-) fuel cells, and lithium ion batteries.

  18. Method to obtain carbon nano-onions by pyrolisys of propane

    Science.gov (United States)

    Garcia-Martin, Tomas; Rincon-Arevalo, Pedro; Campos-Martin, Gemma

    2013-11-01

    We present a new and simple method for carbon nano-onions (CNOs) production which is based on the pyrolysis of Propane. CNOs are originated in a laminar premixed Propane/Oxygen flame of approximately 1.8 of stoichiometric coefficient. The stream of gasses resulting from the combustion drives the carbon particles towards the aluminium surface on which nano-onions are deposited and collected. The structure and size of the deposited carbon onion on the metal wall are characterized by High Resolution Transmission Electron Microscopy technique (HRTEM). The experimental images show the presence of two different types of CNOs. The first particles have diameters in the range of 18-25 nm and the second ones around 10 nm.

  19. Static and free vibration analysis of carbon nano wires based on Timoshenko beam theory using differential quadrature method

    Directory of Open Access Journals (Sweden)

    Maziar Janghorban

    Full Text Available Static and free vibration analysis of carbon nano wires with rectangular cross section based on Timoshenko beam theory is studied in this research. Differential quadrature method (DQM is employed to solve the governing equations. From the knowledge of author, it is the first time that free vibration of nano wires is investigated. It is also the first time that differential quadrature method is used for bending analysis of nano wires.

  20. Scalable 2D Hierarchical Porous Carbon Nanosheets for Flexible Supercapacitors with Ultrahigh Energy Density.

    Science.gov (United States)

    Yao, Lei; Wu, Qin; Zhang, Peixin; Zhang, Junmin; Wang, Dongrui; Li, Yongliang; Ren, Xiangzhong; Mi, Hongwei; Deng, Libo; Zheng, Zijian

    2018-03-01

    2D carbon nanomaterials such as graphene and its derivatives, have gained tremendous research interests in energy storage because of their high capacitance and chemical stability. However, scalable synthesis of ultrathin carbon nanosheets with well-defined pore architectures remains a great challenge. Herein, the first synthesis of 2D hierarchical porous carbon nanosheets (2D-HPCs) with rich nitrogen dopants is reported, which is prepared with high scalability through a rapid polymerization of a nitrogen-containing thermoset and a subsequent one-step pyrolysis and activation into 2D porous nanosheets. 2D-HPCs, which are typically 1.5 nm thick and 1-3 µm wide, show a high surface area (2406 m 2 g -1 ) and with hierarchical micro-, meso-, and macropores. This 2D and hierarchical porous structure leads to robust flexibility and good energy-storage capability, being 139 Wh kg -1 for a symmetric supercapacitor. Flexible supercapacitor devices fabricated by these 2D-HPCs also present an ultrahigh volumetric energy density of 8.4 mWh cm -3 at a power density of 24.9 mW cm -3 , which is retained at 80% even when the power density is increased by 20-fold. The devices show very high electrochemical life (96% retention after 10000 charge/discharge cycles) and excellent mechanical flexibility. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Porous carbon-free SnSb anodes for high-performance Na-ion batteries

    Science.gov (United States)

    Choi, Jeong-Hee; Ha, Choong-Wan; Choi, Hae-Young; Seong, Jae-Wook; Park, Cheol-Min; Lee, Sang-Min

    2018-05-01

    A simple melt-spinning/chemical-etching process is developed to create porous carbon-free SnSb anodes. Sodium ion batteries (SIBs) incorporating these anodes exhibit excellent electrochemical performances by accomodating large volume changes during repeated cycling. The porous carbon-free SnSb anode produced by the melt-spinning/chemical-etching process shows a high reversible capacity of 481 mAh g-1, high ICE of 80%, stable cyclability with a high capacity retention of 99% after 100 cycles, and a fast rate capability of 327 mAh g-1 at 4C-rate. Ex-situ X-ray diffraction and high resolution-transmission electron microscopy analyses demonstrate that the synthesized porous carbon-free SnSb anodes involve the highly reversible reaction with sodium through the conversion and recombination reactions during sodiation/desodiation process. The novel and simple melt-spinning/chemical-etching synthetic process represents a technological breakthrough in the commercialization of Na alloy-able anodes for SIBs.

  2. 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.

  3. Ordered hierarchically porous carbon codoped with iron and nitrogen as electrocatalyst for the oxygen reduction reaction.

    Science.gov (United States)

    Deng, Chengwei; Zhong, Hexiang; Yao, Lan; Liu, Sisi; Xu, Zhuang; Zhang, Huamin

    2014-12-01

    N-doped carbon catalysts have attracted great attention as potential alternatives to expensive Pt-based catalysts used in fuel cells. Herein, an ordered hierarchically porous carbon codoped with N and Fe (Fe-NOHPC) is prepared by an evaporation-induced self-assembly process followed by carbonization under ammonia. The soft template and Fe species promote the formation of the porous structure and facilitate the oxygen reduction reaction (ORR).The catalyst possesses an ordered hierarchically porous structure with a large surface area (1172.5 m(2) g(-1) ) and pore volume of 1.03 cm(3) g(-1) . Compared to commercial 20% Pt/C, it exhibits better ORR catalytic activity and higher stability as well as higher methanol tolerance in an alkaline electrolyte, which demonstrates its potential use in fuel cells as a nonprecious cathode catalyst. The N configuration, Fe species, and pore structure of the catalysts are believed to correlate with its high catalytic activity. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Electrochemical characteristics of vanadium redox reactions on porous carbon electrodes for microfluidic fuel cell applications

    International Nuclear Information System (INIS)

    Lee, Jin Wook; Hong, Jun Ki; Kjeang, Erik

    2012-01-01

    Microfluidic vanadium redox fuel cells are membraneless and catalyst-free fuel cells comprising a microfluidic channel network with two porous carbon electrodes. The anolyte and catholyte for fuel cell operation are V(II) and V(V) in sulfuric acid based aqueous solution. In the present work, the electrochemical characteristics of the vanadium redox reactions are investigated on commonly used porous carbon paper electrodes and compared to a standard solid graphite electrode as baseline. Half-cell electrochemical impedance spectroscopy is applied to measure the overall ohmic resistance and resistivity of the electrodes. Kinetic parameters for both V(II) and V(V) discharging reactions are extracted from Tafel plots and compared for the different electrodes. Cyclic voltammetry techniques reveal that the redox reactions are irreversible and that the magnitudes of peak current density vary significantly for each electrode. The obtained kinetic parameters for the carbon paper are implemented into a numerical simulation and the results show a good agreement with measured polarization curves from operation of a microfluidic vanadium redox fuel cell employing the same material as flow-through porous electrodes. Recommendations for microfluidic fuel cell design and operation are provided based on the measured trends.

  5. Digested sludge-derived three-dimensional hierarchical porous carbon for high-performance supercapacitor electrode.

    Science.gov (United States)

    Zhang, Jia-Jia; Fan, Hao-Xiang; Dai, Xiao-Hu; Yuan, Shi-Jie

    2018-04-01

    Digested sludge, as the main by-product of the sewage sludge anaerobic digestion process, still contains considerable organic compounds. In this protocol, we report a facile method for preparing digested sludge-derived self-doped porous carbon material for high-performance supercapacitor electrodes via a sustainable pyrolysis/activation process. The obtained digested sludge-derived carbon material (HPDSC) exhibits versatile O-, N-doped hierarchical porous framework, high specific surface area (2103.6 m 2  g -1 ) and partial graphitization phase, which can facilitate ion transport, provide more storage sites for electrolyte ions and enhance the conductivity of active electrode materials. The HPDSC-based supercapacitor electrodes show favourable energy storage performance, with a specific capacitance of 245 F g -1 at 1.0 A g -1 in 0.5 M Na 2 SO 4 ; outstanding cycling stability, with 98.4% capacitance retention after 2000 cycles; and good rate performance (211 F g -1 at 11 A g -1 ). This work provides a unique self-doped three-dimensional hierarchical porous carbon material with a favourable charge storage capacity and at the same time finds a high value-added and environment-friendly strategy for disposal and recycling of digested sludge.

  6. Digested sludge-derived three-dimensional hierarchical porous carbon for high-performance supercapacitor electrode

    Science.gov (United States)

    Zhang, Jia-Jia; Fan, Hao-Xiang; Dai, Xiao-Hu; Yuan, Shi-Jie

    2018-04-01

    Digested sludge, as the main by-product of the sewage sludge anaerobic digestion process, still contains considerable organic compounds. In this protocol, we report a facile method for preparing digested sludge-derived self-doped porous carbon material for high-performance supercapacitor electrodes via a sustainable pyrolysis/activation process. The obtained digested sludge-derived carbon material (HPDSC) exhibits versatile O-, N-doped hierarchical porous framework, high specific surface area (2103.6 m2 g-1) and partial graphitization phase, which can facilitate ion transport, provide more storage sites for electrolyte ions and enhance the conductivity of active electrode materials. The HPDSC-based supercapacitor electrodes show favourable energy storage performance, with a specific capacitance of 245 F g-1 at 1.0 A g-1 in 0.5 M Na2SO4; outstanding cycling stability, with 98.4% capacitance retention after 2000 cycles; and good rate performance (211 F g-1 at 11 A g-1). This work provides a unique self-doped three-dimensional hierarchical porous carbon material with a favourable charge storage capacity and at the same time finds a high value-added and environment-friendly strategy for disposal and recycling of digested sludge.

  7. Nano-scaled carbon fillers and their functional polymer composites

    NARCIS (Netherlands)

    Gomes Ghislandi, M.

    2012-01-01

    The manufacturing of low density conductive plastics, that could replace metals in many applications, is a challenging target that has been pursued by several technological segments. The incorporation of carbon nanofillers, namely carbon nanotubes and graphene, into a polymer matrix is a recent and

  8. Synthesis of nano-carbon (nanotubes, nanofibres, graphene ...

    Indian Academy of Sciences (India)

    In the present study, we report the synthesis of carbon nanotubes (CNTs) using a new natural precursor: castor oil. The CNTs were synthesized by spray pyrolysis of castor oil–ferrocene solution at 850°C under an Ar atmosphere. We also report the synthesis of carbon nitrogen (C–N) nanotubes using castor ...

  9. Preparation of porous bio-char and activated carbon from rice husk by leaching ash and chemical activation.

    Science.gov (United States)

    Ahiduzzaman, Md; Sadrul Islam, A K M

    2016-01-01

    Preparation porous bio-char and activated carbon from rice husk char study has been conducted in this study. Rice husk char contains high amount silica that retards the porousness of bio-char. Porousness of rice husk char could be enhanced by removing the silica from char and applying heat at high temperature. Furthermore, the char is activated by using chemical activation under high temperature. In this study no inert media is used. The study is conducted at low oxygen environment by applying biomass for consuming oxygen inside reactor and double crucible method (one crucible inside another) is applied to prevent intrusion of oxygen into the char. The study results shows that porous carbon is prepared successfully without using any inert media. The adsorption capacity of material increased due to removal of silica and due to the activation with zinc chloride compared to using raw rice husk char. The surface area of porous carbon and activated carbon are found to be 28, 331 and 645 m(2) g(-1) for raw rice husk char, silica removed rice husk char and zinc chloride activated rice husk char, respectively. It is concluded from this study that porous bio-char and activated carbon could be prepared in normal environmental conditions instead of inert media. This study shows a method and possibility of activated carbon from agro-waste, and it could be scaled up for commercial production.

  10. Porous carbon as electrode material in direct ethanol fuel cells (DEFCs) synthesized by the direct carbonization of MOF-5

    KAUST Repository

    Khan, Inayatali

    2014-01-12

    Porous carbon (PC-900) was prepared by direct carbonization of porous metal-organic framework (MOF)-5 (Zn4O(bdc)3, bdc=1,4-benzenedicarboxylate) at 900 °C. The carbon material was deposited with PtM (M=Fe, Ni, Co, and Cu (20 %) metal loading) nanoparticles using the polyol reduction method, and catalysts PtM/PC-900 were designed for direct ethanol fuel cells (DEFCs). However, herein, we are reporting PtFe/PC-900 catalyst combination which has exhibited superior performance among other options. This catalyst was characterized by powder XRD, high-resolution transmission electron microscopy (HRTEM), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and selected area electron diffraction (SAED) technique. The electrocatalytic capability of the catalyst for ethanol electrooxidation was investigated using cyclic voltammetry and direct ethanol single cell testing. The results were compared with those of PtFe and Pt supported on Vulcan XC72 carbon catalysts (PFe/CX-72 and Pt/XC-72) prepared via the same method. It has been observed that the catalyst PtFe/PC-900 developed in this work showed an outstanding normalized activity per gram of Pt (6.8 mA/g Pt) and superior power density (121 mW/cm2 at 90 °C) compared to commercially available carbon-supported catalysts. © Springer-Verlag Berlin Heidelberg 2014.

  11. Porous carbon as electrode material in direct ethanol fuel cells (DEFCs) synthesized by the direct carbonization of MOF-5

    KAUST Repository

    Khan, Inayatali; Badshah, Amin; Haider, Naghma; Ullah, Shafiq; Anjum, Dalaver H.; Nadeem, Muhammad Arif

    2014-01-01

    Porous carbon (PC-900) was prepared by direct carbonization of porous metal-organic framework (MOF)-5 (Zn4O(bdc)3, bdc=1,4-benzenedicarboxylate) at 900 °C. The carbon material was deposited with PtM (M=Fe, Ni, Co, and Cu (20 %) metal loading) nanoparticles using the polyol reduction method, and catalysts PtM/PC-900 were designed for direct ethanol fuel cells (DEFCs). However, herein, we are reporting PtFe/PC-900 catalyst combination which has exhibited superior performance among other options. This catalyst was characterized by powder XRD, high-resolution transmission electron microscopy (HRTEM), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and selected area electron diffraction (SAED) technique. The electrocatalytic capability of the catalyst for ethanol electrooxidation was investigated using cyclic voltammetry and direct ethanol single cell testing. The results were compared with those of PtFe and Pt supported on Vulcan XC72 carbon catalysts (PFe/CX-72 and Pt/XC-72) prepared via the same method. It has been observed that the catalyst PtFe/PC-900 developed in this work showed an outstanding normalized activity per gram of Pt (6.8 mA/g Pt) and superior power density (121 mW/cm2 at 90 °C) compared to commercially available carbon-supported catalysts. © Springer-Verlag Berlin Heidelberg 2014.

  12. AC dielectrophoresis alignment of single-walled carbon nano tubes (SWNTS) and palladium nano wires for hydrogen gas sensor

    International Nuclear Information System (INIS)

    Nur Ubaidah Saidin; Nur Ubaidah Saidin; Ying, K.K.; KKhuan, N.I.; Mohammad Hafizuddin Jumali

    2013-01-01

    Full-text: Using AC electric field, nano wires or nano tubes can be aligned, chained or accelerated in a direction parallel to the applied field, oriented or concentrated onto designated locations as well as dispersed in controlled manner under high efficiencies. In this work, systematic study on the alignment of nano wires/ nano tubes across the 3 μm-gaps between pairs of micro fabricated gold electrodes was carried out using AC dielectrophoresis technique. Densities and alignment of the nano wires/ nano tubes across the gaps of the electrodes were controlled by the applied AC field strengths and frequencies on the electrodes. Good alignments of SWNTs and Pd nano wires were achieved at an applied frequency of 5 MHz and a field strength as high as 25 V pp for Pd nano wires compared to only 2 V pp for SWNTs. The aligned nano wires/ nano tubes will be functioned as sensor elements for hydrogen gas sensing. (author)

  13. Novel calcified gum Arabic porous nano-composite scaffold for bone tissue regeneration.

    Science.gov (United States)

    Hadavi, M; Hasannia, S; Faghihi, Sh; Mashayekhi, F; Zadeh, H H; Mostofi, S B

    2017-07-08

    The aim of this study was to investigate the biomechanical and biological properties of a nanocomposite scaffold containing both mineral and polysaccharide constituents. Hydroxyapatite nanoparticles (n-HA) was synthesized from dead abra ovata shells using wet chemical methods and was used in different ratios in concert with gum Arabic, a branched plant polysaccharide. N-HA/gum nanocomposite was fabricated with freeze-drying process and characterized by FTIR and SEM for chemical structure and morphology. Porosity was estimated using liquid substitution method. The scaffold mechanical properties were evaluated by compressive test measurement. Osteogenic differentiation was assessed using alkaline phosphatase production and biomineralization was evaluated using Alizarin red assay. Results demonstrated that the hydroxyapatite/gum Arabic nanocomposite had favorable biocompatibility and a similar structure to natural bone matrix. Porous nanocomposite possessed macropore networks with a porosity 87-93% and mean pore size ranging between 164 and 230 μm. The gum/HA with a ratio of 50% w/w HA had the highest compressive modulus of ∼75.3 MPa Pa (MPa) and the ultimate compressive stress of ∼16.6 MPa. C2C12 cells cultured on a scaffold with higher percentage (40 and 50 w/w) of HA demonstrated increased ALP levels and calcium deposition. The data from the present study demonstrated significant changes to the biomechanical properties and osteoconductivity of the nanocomposite scaffold by modulating its mineral content. Nanocomposite scaffolds containing gum and n-HA of 40-50% exhibited highest mechanical properties, as well as supported increased biomineralization. Copyright © 2017 Elsevier Inc. All rights reserved.

  14. Characterization of nano-porous oxides containing aqueous heavy metallic ions

    International Nuclear Information System (INIS)

    Louisfrema, Wilfried

    2016-01-01

    Porous crystalline aluminosilicates such as cationic zeolites, are widely studied because of their adsorption, ion exchange and catalytic properties, which explain their use in many industrial applications. Examples of the latter, which involve in particular multivalent cations, include detergents/softeners, catalytic cracking, or decontamination. Such industrial applications of zeolites all exploit their adsorption properties, which vary as a function of the pore size, comparable to the adsorbing molecules, or chemical composition, which results in charges within the framework, and in turn strong binding or repulsive sites. Importantly, in such applications zeolites are hydrated. Water is involved in the microscopic processes and thus influences all properties of the material. Molecular modeling is a weapon of choice to predict and understand the microscopic properties of the hydrated material, which are difficult to access experimentally. More precisely, the present modeling work deals with the behavior of multivalent cations in hydrated zeolites, in collaboration with experimentalists. Our study on zeolite Y faujasite first allowed us to clarify the migration of sodium cations upon dehydration and to predict the cation localization in the hydrated material in the presence of divalent cations. Furthermore, we rationalized the coupled migration of cations and deformation of the framework upon water adsorption. To this end, we have developed a new method for the analysis of cation localization. The good performance of a polarizable force field demonstrated here paves the way for the study of the dynamics of the whole system, following in particular the simultaneous migration of cations and deformation of the framework. Such an approach could be later extended to other multivalent ions of industrial interest (rare Earths, f-block elements,...). (author)

  15. Enhanced visible-light-driven photocatalytic performance of porous graphitic carbon nitride

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Fei, E-mail: feichang@usst.edu.cn [School of Environment and Architecture, University of Shanghai for Science and Technology, Shanghai 200093 (China); Li, Chenlu; Luo, Jieru; Xie, Yunchao; Deng, Baoqing [School of Environment and Architecture, University of Shanghai for Science and Technology, Shanghai 200093 (China); Hu, Xuefeng, E-mail: xfhu@yic.ac.cn [Key Laboratory of Coastal Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, Shandong 264003 (China)

    2015-12-15

    Graphical abstract: - Highlights: • Porous g-C{sub 3}N{sub 4} samples were fabricated by a facile pyrolysis method. • As-prepared porous g-C{sub 3}N{sub 4} samples showed remarkably enhanced photocatalytic performance. • Holes and radicals ·O{sub 2}{sup −} exerted dominant roles on the photocatalytic process. - Abstract: In this study, a series of porous graphitic carbon nitride (g-C{sub 3}N{sub 4}) materials were fabricated through a direct pyrolysis of protonated melamine by nitric acid solution. These as-prepared porous samples were characterized by a collection of analytical techniques. It was found that a proper concentration of nitric acid solution involved facilitated to generate samples in tube-like morphology with numerous pores, identified with X-ray diffraction patterns, FT-IR spectra, SEM, TEM, and BET measurements. These g-C{sub 3}N{sub 4} samples were subjected to photocatalytic degradation of dye Rhodamine B (RhB) in aqueous under visible-light irradiation. Under identical conditions, those porous g-C{sub 3}N{sub 4} samples showed significantly improved catalytic performance in comparison with the sample prepared without the introduction of nitric acid. In particularly, the best candidate, sample M1:1, showed an apparent reaction rate nearly 6.2 times that of the unmodified counterpart. The enhancement of photocatalytic performance could be attributed to the favorable porous structure with the enlarged specific surface area and the suitable electronic structure as well. In addition, ESR measurements were conducted for the sake of proposing a photocatalytic degradation mechanism.

  16. Effect of sulfur and Nano- carbon black on the mechanical properties of hard rubber

    Directory of Open Access Journals (Sweden)

    Mohamed Hamza Al-Maamori

    2018-01-01

    Full Text Available To improve the properties of hard rubber(Ebonite from natural rubber, added Nano-Carbon black, where measured the properties of tensile, density, hardness and the properties of the vulcanization of a group of samples with different amount of sulfur from 18-36 pphr and different of carbon black (18-26-30 pphr. The results showed that the best carbon black ratio is 30 pphr, where it gives a balance between tensile properties of hand and toughness and flexibility of on the other hand and reduce brittleness in hard rubber.

  17. Hierarchical porous nickel oxide-carbon nanotubes as advanced pseudocapacitor materials for supercapacitors

    Science.gov (United States)

    Su, Aldwin D.; Zhang, Xiang; Rinaldi, Ali; Nguyen, Son T.; Liu, Huihui; Lei, Zhibin; Lu, Li; Duong, Hai M.

    2013-03-01

    Hierarchical porous carbon anode and metal oxide cathode are promising for supercapacitor with both high energy density and high power density. This Letter uses NiO and commercial carbon nanotubes (CNTs) as electrode materials for electrochemical capacitors with high energy storage capacities. Experimental results show that the specific capacitance of the electrode materials for 10%, 30% and 50% CNTs are 279, 242 and 112 F/g, respectively in an aqueous 1 M KOH electrolyte at a charge rate of 0.56 A/g. The maximum specific capacitance is 328 F/g at a charge rate of 0.33 A/g.

  18. Non-oxidic nanoscale composites: single-crystalline titanium carbide nanocubes in hierarchical porous carbon monoliths.

    Science.gov (United States)

    Sonnenburg, Kirstin; Smarsly, Bernd M; Brezesinski, Torsten

    2009-05-07

    We report the preparation of nanoscale carbon-titanium carbide composites with carbide contents of up to 80 wt%. The synthesis yields single-crystalline TiC nanocubes 20-30 nm in diameter embedded in a hierarchical porous carbon matrix. These composites were generated in the form of cylindrical monoliths but can be produced in various shapes using modern sol-gel and nanocasting methods in conjunction with carbothermal reduction. The monolithic material is characterized by a combination of microscopy, diffraction and physisorption. Overall, the results presented in this work represent a concrete design template for the synthesis of non-oxidic nanoscale composites with high surface areas.

  19. High nitrogen-containing cotton derived 3D porous carbon frameworks for high-performance supercapacitors

    Science.gov (United States)

    Fan, Li-Zhen; Chen, Tian-Tian; Song, Wei-Li; Li, Xiaogang; Zhang, Shichao

    2015-10-01

    Supercapacitors fabricated by 3D porous carbon frameworks, such as graphene- and carbon nanotube (CNT)-based aerogels, have been highly attractive due to their various advantages. However, their high cost along with insufficient yield has inhibited their large-scale applications. Here we have demonstrated a facile and easily scalable approach for large-scale preparing novel 3D nitrogen-containing porous carbon frameworks using ultralow-cost commercial cotton. Electrochemical performance suggests that the optimal nitrogen-containing cotton-derived carbon frameworks with a high nitrogen content (12.1 mol%) along with low surface area 285 m2 g-1 present high specific capacities of the 308 and 200 F g-1 in KOH electrolyte at current densities of 0.1 and 10 A g-1, respectively, with very limited capacitance loss upon 10,000 cycles in both aqueous and gel electrolytes. Moreover, the electrode exhibits the highest capacitance up to 220 F g-1 at 0.1 A g-1 and excellent flexibility (with negligible capacitance loss under different bending angles) in the polyvinyl alcohol/KOH gel electrolyte. The observed excellent performance competes well with that found in the electrodes of similar 3D frameworks formed by graphene or CNTs. Therefore, the ultralow-cost and simply strategy here demonstrates great potential for scalable producing high-performance carbon-based supercapacitors in the industry.

  20. High nitrogen-containing cotton derived 3D porous carbon frameworks for high-performance supercapacitors

    Science.gov (United States)

    Fan, Li-Zhen; Chen, Tian-Tian; Song, Wei-Li; Li, Xiaogang; Zhang, Shichao

    2015-01-01

    Supercapacitors fabricated by 3D porous carbon frameworks, such as graphene- and carbon nanotube (CNT)-based aerogels, have been highly attractive due to their various advantages. However, their high cost along with insufficient yield has inhibited their large-scale applications. Here we have demonstrated a facile and easily scalable approach for large-scale preparing novel 3D nitrogen-containing porous carbon frameworks using ultralow-cost commercial cotton. Electrochemical performance suggests that the optimal nitrogen-containing cotton-derived carbon frameworks with a high nitrogen content (12.1 mol%) along with low surface area 285 m2 g−1 present high specific capacities of the 308 and 200 F g−1 in KOH electrolyte at current densities of 0.1 and 10 A g−1, respectively, with very limited capacitance loss upon 10,000 cycles in both aqueous and gel electrolytes. Moreover, the electrode exhibits the highest capacitance up to 220 F g−1 at 0.1 A g−1 and excellent flexibility (with negligible capacitance loss under different bending angles) in the polyvinyl alcohol/KOH gel electrolyte. The observed excellent performance competes well with that found in the electrodes of similar 3D frameworks formed by graphene or CNTs. Therefore, the ultralow-cost and simply strategy here demonstrates great potential for scalable producing high-performance carbon-based supercapacitors in the industry. PMID:26472144

  1. Adsorption of malachite green and iodine on rice husk-based porous carbon

    International Nuclear Information System (INIS)

    Guo Yupeng; Zhang Hui; Tao Nannan; Liu Yanhua; Qi Juirui; Wang Zichen; Xu Hongding

    2003-01-01

    Adsorption isotherms of I 2 and malachite green (MG) by rice husk-based porous carbons (RHCs) from aqueous medium have been studied. Three samples of carbons prepared by NaOH-activation, three samples prepared by KOH-activation and two samples of commercial carbons have been studied. And the adsorption isotherms have been determined after modifying the carbon surfaces by oxidation with nitric acid and hydrogen peroxide and after degassing at 800 deg. C. The results have been found to follow the Freundlich adsorption isotherm. Three samples of N series have larger capacity for removing I 2 and MG from solution compared to that of the tested commercial carbons. The adsorption capacity of I 2 is similar for K series and commercial carbons. And the capacity of commercial carbons for MG is larger than K series. The adsorption capacity of I 2 on oxidation carbons has increased for hydrogen peroxide treatment and decreased for nitric acid, and that of MG is decreased. But the adsorption capacities of I 2 and MG increase on degassing. On the other hand, the adsorption of I 2 increases after modifying the carbon surfaces by HCl without oxidation. Suitable mechanisms have been proposed

  2. Hydroquinone and Quinone-Grafted Porous Carbons for Highly Selective CO2 Capture from Flue Gases and Natural Gas Upgrading.

    Science.gov (United States)

    Wang, Jun; Krishna, Rajamani; Yang, Jiangfeng; Deng, Shuguang

    2015-08-04

    Hydroquinone and quinone functional groups were grafted onto a hierarchical porous carbon framework via the Friedel-Crafts reaction to develop more efficient adsorbents for the selective capture and removal of carbon dioxide from flue gases and natural gas. The oxygen-doped porous carbons were characterized with scanning electron microscopy, transmission electron microscopy, X-ray powder diffraction, Fourier transform infrared spectroscopy, and Raman spectroscopy. CO2, CH4, and N2 adsorption isotherms were measured and correlated with the Langmuir model. An ideal adsorbed solution theory (IAST) selectivity for the CO2/N2 separation of 26.5 (298 K, 1 atm) was obtained on the hydroquinone-grafted carbon, which is 58.7% higher than that of the pristine porous carbon, and a CO2/CH4 selectivity value of 4.6 (298 K, 1 atm) was obtained on the quinone-grafted carbon (OAC-2), which represents a 28.4% improvement over the pristine porous carbon. The highest CO2 adsorption capacity on the oxygen-doped carbon adsorbents is 3.46 mmol g(-1) at 298 K and 1 atm. In addition, transient breakthrough simulations for CO2/CH4/N2 mixture separation were conducted to demonstrate the good separation performance of the oxygen-doped carbons in fixed bed adsorbers. Combining excellent adsorption separation properties and low heats of adsorption, the oxygen-doped carbons developed in this work appear to be very promising for flue gas treatment and natural gas upgrading.

  3. Nitrogen-Rich Porous Polymers for Carbon Dioxide and Iodine Sequestration for Environmental Remediation.

    Science.gov (United States)

    Abdelmoaty, Yomna H; Tessema, Tsemre-Dingel; Choudhury, Fatema Akthar; El-Kadri, Oussama M; El-Kaderi, Hani M

    2018-05-09

    The use of fossil fuels for energy production is accompanied by carbon dioxide release into the environment causing catastrophic climate changes. Meanwhile, replacing fossil fuels with carbon-free nuclear energy has the potential to release radioactive iodine during nuclear waste processing and in case of a nuclear accident. Therefore, developing efficient adsorbents for carbon dioxide and iodine capture is of great importance. Two nitrogen-rich porous polymers (NRPPs) derived from 4-bis-(2,4-diamino-1,3,5-triazine)-benzene building block were prepared and tested for use in CO 2 and I 2 capture. Copolymerization of 1,4-bis-(2,4-diamino-1,3,5-triazine)-benzene with terephthalaldehyde and 1,3,5-tris(4-formylphenyl)benzene in dimethyl sulfoxide at 180 °C afforded highly porous NRPP-1 (SA BET = 1579 m 2 g -1 ) and NRPP-2 (SA BET = 1028 m 2 g -1 ), respectively. The combination of high nitrogen content, π-electron conjugated structure, and microporosity makes NRPPs very effective in CO 2 uptake and I 2 capture. NRPPs exhibit high CO 2 uptakes (NRPP-1, 6.1 mmol g -1 and NRPP-2, 7.06 mmol g -1 ) at 273 K and 1.0 bar. The 7.06 mmol g -1 CO 2 uptake by NRPP-2 is the second highest value reported to date for porous organic polymers. According to vapor iodine uptake studies, the polymers display high capacity and rapid reversible uptake release for I 2 (NRPP-1, 192 wt % and NRPP-2, 222 wt %). Our studies show that the green nature (metal-free) of NRPPs and their effective capture of CO 2 and I 2 make this class of porous materials promising for environmental remediation.

  4. Towards ultrahigh volumetric capacitance: graphene derived highly dense but porous carbons for supercapacitors

    Science.gov (United States)

    Tao, Ying; Xie, Xiaoying; Lv, Wei; Tang, Dai-Ming; Kong, Debin; Huang, Zhenghong; Nishihara, Hirotomo; Ishii, Takafumi; Li, Baohua; Golberg, Dmitri; Kang, Feiyu; Kyotani, Takashi; Yang, Quan-Hong

    2013-10-01

    A small volumetric capacitance resulting from a low packing density is one of the major limitations for novel nanocarbons finding real applications in commercial electrochemical energy storage devices. Here we report a carbon with a density of 1.58 g cm-3, 70% of the density of graphite, constructed of compactly interlinked graphene nanosheets, which is produced by an evaporation-induced drying of a graphene hydrogel. Such a carbon balances two seemingly incompatible characteristics: a porous microstructure and a high density, and therefore has a volumetric capacitance for electrochemical capacitors (ECs) up to 376 F cm-3, which is the highest value so far reported for carbon materials in an aqueous electrolyte. More promising, the carbon is conductive and moldable, and thus could be used directly as a well-shaped electrode sheet for the assembly of a supercapacitor device free of any additives, resulting in device-level high energy density ECs.

  5. Pore-Fractal Structure in Porous Carbons Made from Corn and Wheat

    Science.gov (United States)

    Kapoor, Y. M.; Schmidt, P. W.; Rice, Randall D.; Shulse, Laural; Voss, D. J.; Venkatraman, A.; Fan, L. T.; Walawender, W. P.; Rieker, T. P.

    1998-03-01

    Small-angle X-ray scattering has been used in a study of the pore structure of some porous and activated carbons on length scales between about 5 and 10^4 ÅThe carbons were obtained by pyrolysis and activation of wheat and American corn (maize). The scattering data showed that in each carbon there are at least two of the following four types of pores: (1) pores with diameters of at least 10^4 Åpores with smooth or fractal surfaces and diameters of at least 5 x 10^3 Åpore-fractals with diameters of no more than about 10^3 Åand (4) pores with diameters no larger than 100 ÅThe relation between the pore structure and the procedure used to obtain the carbon and will be discussed.

  6. Hydrogen storage in carbon nano-tubes; Stockage d'hydrogene dans les nanotubes de carbone

    Energy Technology Data Exchange (ETDEWEB)

    Becher, M.; Haluska, M.; Hirscher, M. [Max-Planck-Institut fuer Metallforschung, Stuttgart (Germany); Quintel, A.; Skakalova, V.; Dettlaff-Weglikovska, U.; Chen, X.; Hulman, M.; Choi, Y.; Roth, S.; Meregalli, V.; Parrinello, M. [Max-Planck-Institut fuer Festkoerperforschung, Stuttgart (Germany); Strobel, R.; Jorissen, L. [Zentrum fur Sonnenenergie und Wasserstoff-Forschung, Ulm (Germany); Kappes, M.M. [Karlsruhe Univ., Institut fur Physikalische Chemie(Germany); Fink, J. [Institut fur Festkorper-Und Werkstoffforschun, Dresden (Germany); Zuttel, A. [Fribourg Univ., Dept. Physique (Switzerland); Stepanek, I.; Bernier, P. [Montpellier-2 Univ., GDPC, 34 (France)

    2003-11-01

    Hydrogen storage in new nano-structured carbonic materials is a topic for lively discussion. The measured storage capacities of these materials, which have been announced in the literature during the last ten years are spread over an enormous range from about 0.1 wt% up to 67 wt%. This paper will give a report on the state of the art of hydrogen storage in carbon nano-structures. We shall critically review the recent 'key publications' on this topic, which claim storage capacities clearly above the technological bench mark set by the US Department of Energy, and we shall report new results which have been obtained in a joint project sponsored by the Federal Ministry for Education and Research in Germany (BMBF). (authors)

  7. Nano-scaled iron-carbon precipitates in HSLC and HSLA steels

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    This paper studies the composition, quantity and particle size distribution of nano-scaled precipitates with size less than 20 nm in high strength low carbon (HSLC) steel and their effects on mechanical properties of HSLC steel by means of mass balance calculation of nano-scaled precipitates measured by chemical phase analysis plus SAXS method, high-resolution TEM analysis and thermodynamics calculation, as well as temper rapid cooling treatment of ZJ330. It is found that there existed a large quantity of nano-scaled iron-carbon precipitates with size less than 18 nm in low carbon steel produced by CSP and they are mainly Fe-O-C and Fe-Ti-O-C precipitates formed below temperature A1. These precipitates have ob- vious precipitation strengthening effect on HSLC steel and this may be regarded as one of the main reasons why HSLC steel has higher strength. There also existed a lot of iron-carbon precipitates with size less than 36 nm in HSLA steels.

  8. Nano-scaled iron-carbon precipitates in HSLC and HSLA steels

    Institute of Scientific and Technical Information of China (English)

    FU Jie; WU HuaJie; LIU YangChun; KANG YongLin

    2007-01-01

    This paper studies the composition, quantity and particle size distribution of nano-scaled precipitates with size less than 20 nm in high strength Iow carbon (HSLC) steel and their effects on mechanical properties of HSLC steel by means of mass balance calculation of nano-scaled precipitates measured by chemical phase analysis plus SAXS method, high-resolution TEM analysis and thermodynamics calculation, as well as temper rapid cooling treatment of ZJ330. It is found that there existed a large quantity of nano-scaled iron-carbon precipitates with size less than 18 nm in Iow carbon steel produced by CSP and they are mainly Fe-O-C and Fe-Ti-O-C precipitates formed below temperature A1. These precipitates have obvious precipitation strengthening effect on HSLC steel and this may be regarded as one of the main reasons why HSLC steel has higher strength. There also existed a lot of iron-carbon precipitates with size less than 36 nm in HSLA steels.

  9. Experimental investigation on carbon nano tubes coated brass rectangular extended surfaces

    International Nuclear Information System (INIS)

    Senthilkumar, Rajendran; Prabhu, Sethuramalingam; Cheralathan, Marimuthu

    2013-01-01

    Finned surface has been extensively used for free convection cooling of internal combustion engines and several electronic kits etc. Here rectangular brass fin was preferred for analysis. Thermocouples were attached all over the surface of the fin in equal distances. The measurement of surface temperature and calculated convective heat transfer rate were reported for several heat input values. The overall system performance can be improved by enhancing heat transfer rate of extended surfaces. Based on the above requirement, brass surface was coated by carbon nano tubes. The temperature and heat transfer characteristics were investigated using Taguchi method for experimental design. Finally the performances of coated and non-coated rectangular brass fins were compared. The average percentage of increase in heat transfer rate was proved around 12% for carbon nanocoated rectangular brass fins. - Graphical abstract: The designed Natural and Forced convection Heat Transfer Test Rig measures the enhanced rate of heat transfer for nano coated rectangular fins than in non-coated fins. Highlights: ► Rectangular brass fins were preferred for convective heat transfer process. ► The rectangular brass fins are coated with multi wall carbon nano tubes in EBPVD process with nanometer thickness. ► Temperature and heat transfer rate were investigated for nanocoated and non-coated fins by using Taguchi method. ► Multi wall carbon nanotubes act as a pin fin to enhance surface area for effective convective heat transfer rate.

  10. Multiscale Characterization of Structural Compositional and Textural Heterogeneity of Nano-porous Geomaterials

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, Hongkyu [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Geomechanics Dept.

    2017-09-01

    The purpose of the project was to perform multiscale characterization of low permeability rocks to determine the effect of physical and chemical heterogeneity on the poromechanical and flow responses of shales and carbonate rocks with a broad range of physical and chemical heterogeneity . An integrated multiscale imaging of shale and carbonate rocks from nanometer to centimeter scales include s dual focused ion beam - scanning electron microscopy (FIB - SEM) , micro computed tomography (micro - CT) , optical and confocal microscopy, and 2D and 3D energy dispersive spectroscopy (EDS). In addition, mineralogical mapping and backscattered imaging with nanoindentation testing advanced the quantitative evaluat ion of the relationship between material heterogeneity and mechanical behavior. T he spatial distribution of compositional heterogeneity, anisotropic bedding patterns, and mechanical anisotropy were employed as inputs for brittle fracture simulations using a phase field model . Comparison of experimental and numerical simulations reveal ed that proper incorporation of additional material information, such as bedding layer thickness and other geometrical attributes of the microstructures, can yield improvements on the numerical prediction of the mesoscale fracture patterns and hence the macroscopic effective toughness. Overall, a comprehensive framework to evaluate the relationship between mechanical response and micro-lithofacial features can allow us to make more accurate prediction of reservoir performance by developing a multi - scale understanding of poromechanical response to coupled chemical and mechanical interactions for subsurface energy related activities.

  11. Comparison of the mechanical properties between carbon nanotube and nanocrystalline cellulose polypropylene based nano-composites

    International Nuclear Information System (INIS)

    Huang, Jun; Rodrigue, Denis

    2015-01-01

    Highlights: • SWCNT and NCC can effectively improve the mechanical properties of nano-composites. • SWCNT is more effective than NCC to increase modulus and strength. • Longer NCC is more effective to improve the mechanical properties of nano-composites. • It is more economic to use NCC than SWCNT to improve mechanical properties. - Abstract: Using beam and tetrahedron elements to simulate nanocrystalline cellulose (NCC), single wall carbon nanotube (SWCNT) and polypropylene (PP), finite element method (FEM) is used to predict the mechanical properties of nano-composites. The bending, shear and torsion behaviors of nano-composites are especially investigated due to the limited amount of information in the present literature. First, mixed method (MM) and FEM are used to compare the bending stiffness of NCC/PP and SWCNT/PP composites. Second, based on mechanics of materials, the shear moduli of both types of nano-composites are obtained. Finally, fixing the number of fibers and for different volume contents, four NCC lengths are used to determine the mechanical properties of the composites. The bending and shearing performances are also compared between NCC and SWCNT based composites. In all cases, the elastic–plastic analyses are carried out and the stress or strain distributions for specific regions are also investigated. From all the results obtained, an economic analysis shows that NCC is more interesting than SWCNT to reinforce PP

  12. Micro- and Nano- Porous Adsorptive Materials for Removal of Contaminants from Water at Point-of-Use

    Science.gov (United States)

    Yakub, Ismaiel

    Water is food, a basic human need and a fundamental human right, yet hundreds of millions of people around the world do not have access to clean drinking water. As a result, about 5000 people die each day from preventable water borne diseases. This dissertation presents the results of experimental and theoretical studies on three different types of porous materials that were developed for the removal of contaminants from water at point of use (household level). First, three compositionally distinct porous ceramic water filters (CWFs) were made from a mixture of redart clay and sieved woodchips and processed into frustum shape. The filters were tested for their flow characteristics and bacteria filtration efficiencies. Since, the CWFs are made from brittle materials, and may fail during processing, transportation and usage, the mechanical and physical properties of the porous clays were characterized, and used in modeling designed to provide new insights for the design of filter geometries. The mechanical/physical properties that were characterized include: compressive strength, flexural strength, facture toughness and resistance curve behavior, keeping in mind the anisotropic nature of the filter structure. The measured flow characteristics and mechanical/physical properties were then related to the underlying porosity and characteristic pore size. In an effort to quantify the adhesive interactions associated with filtration phenomena, atomic force microscopy (AFM) was used to measure the adhesion between bi-material pairs that are relevant to point-of-use ceramic water filters. The force microscopy measurements of pull-off force and adhesion energy were used to rank the adhesive interactions. Similarly, the adsorption of fluoride to hydroxyapatite-doped redart clay was studied using composites of redart clay and hydroxyapatite (C-HA). The removal of fluoride from water was explored by carrying out adsorption experiments on C-HA adsorbents with different ratios of

  13. Synthesis and electrochemical capacitive properties of nitrogen-doped porous carbon micropolyhedra by direct carbonization of zeolitic imidazolate framework-11

    Energy Technology Data Exchange (ETDEWEB)

    Hao, Fei; Li, Li; Zhang, Xiaohua, E-mail: mickyxie@hnu.edu.cn; Chen, Jinhua, E-mail: chenjinhua@hnu.edu.cn

    2015-06-15

    Highlights: • Nitrogen-doped porous carbon micropolyhedra (N-PCMPs) were prepared from ZIF-11. • The activated N-PCMPs with fused KOH (N-PCMPs-A) have high specific surface area. • N-PCMPs-A exhibits high specific capacitance. • N-PCMPs-A reveals good cycling performance even at a high current density. - Abstract: Nitrogen-doped porous carbon micropolyhedra (N-PCMPs) were successfully prepared by direct carbonization of ZIF-11 polyhedra and further activated with fused KOH to obtain N-PCMPs-A. The morphology and microstructure of samples were examined by scanning electron microscopy, X-ray diffraction, and micropore and chemisorption analyzer. Electrochemical properties were characterized by cyclic voltammetry and galvanostatic charge/discharge method in 1.0 M H{sub 2}SO{sub 4} aqueous solution on a standard three-electrode system. Results show that, compared with N-PCMPs, N-PCMPs-A has higher specific surface area (2188 m{sup 2} g{sup −1}) and exhibits improved electrochemical capacitive properties (307 F g{sup −1} at 1.0 A g{sup −1}). The mass specific capacitance of N-PCMPs-A is also higher than that of most MOF-derived carbons, some carbide-derived carbons and carbon aerogel-derived carbons. In addition, the capacitance of the N-PCMPs-A retains 90% after 4000 cycles even at a high current density of 10 A g{sup −1}. These imply that N-PCMPs-A is the promising materials for the construction of a high-performance supercapacitor.

  14. Free convection boundary layer flow past a horizontal flat plate embedded in porous medium filled by nano-fluid containing gyro-tactic microorganisms

    Energy Technology Data Exchange (ETDEWEB)

    Aziz, A. [Department of Mechanical Engineering, School of Engineering and Applied Science, Gonzaga University, Spokane, WA 99258 (United States); Khan, W.A. [Department of Engineering Sciences, National University of Sciences and Technology, Karachi 75350 (Pakistan); Pop, I. [Department of Applied Mathematics, Babes-Bolyai University, Cluj-Napoca (Romania)

    2012-06-15

    The steady boundary layer free convection flow past a horizontal flat plate embedded in a porous medium filled by a water-based nano-fluid containing gyro-tactic microorganisms is investigated. The Oberbeck-Boussinesq approximation is assumed in the analysis. The effects of bio-convection parameters on the dimensionless velocity, temperature, nano-particle concentration and density of motile microorganisms as well as on the local Nusselt, Sherwood and motile microorganism numbers are investigated and presented graphically. In the absence of bio-convection, the results are compared with the existing data in the open literature and found to be in good agreement. The bio-convection parameters strongly influence the heat, mass, and motile microorganism transport rates. (authors)

  15. Effects of inherent/enhanced solid acidity and morphology of diatomite templates on the synthesis and porosity of hierarchically porous carbon.

    Science.gov (United States)

    Liu, Dong; Yuan, Peng; Tan, Daoyong; Liu, Hongmei; Fan, Mingde; Yuan, Aihua; Zhu, Jianxi; He, Hongping

    2010-12-21

    The inherent or enhanced solid acidity of raw or activated diatomite is found to have significant effects on the synthesis of hierarchically porous diatomite-templated carbon with high surface area and special porous structure. The solid acidity makes raw/activated diatomite a catalyst for the generation of porous carbon, and the porous parameters of the carbon products are strongly dependent on the solid acidity of diatomite templates. The morphology of diatomite also dramatically affects the textural structure of porous carbon. Two types of macroporous structures in the carbon product, the partially solid pillars and the ordered hollow tubes, derive from the replication of the central and the edge pores of diatom shell, respectively. The hierarchically porous carbon shows good capability for the adsorption of solvent naphtha and H(2), enabling potential applications in adsorption and gas storage.

  16. Two-dimensional hierarchical porous carbon composites derived from corn stalks for electrode materials with high performance

    International Nuclear Information System (INIS)

    Xu, Haitao; Zhang, Huijuan; Ouyang, Ya; Liu, Li; Wang, Yu

    2016-01-01

    Highlights: • Novel 2D porous carbon sheets from cornstalks are obtained for the first time. • The hierarchical porous carbon nansheets are gained by chemical activation. • The porous structure facilitates ion transfer and Li-ion absorption. • The strategy are applied to both cathode and anode electrode materials. • The porous nanocomposites exhibit excellent electrochemical performance. - Abstract: Herein, we propose a novel and green strategy to convert crop stalks waste into hierarchical porous carbon composites for electrode materials of lithium-ion batteries. In the method, the sustainable crop stalks, an abundant agricultural byproduct, is recycled and treated by a simple and clean chemical activation process. Afterwards, the obtained porous template is adopted for large-scale production of high-performance anode and cathode materials for lithium-ion batteries. Due to the large surface area, hierarchical porous structures and subsize of the functional particles, the electrode materials manifest excellent electrochemical performance. In particular, the prepared TiO 2 /C composite presents a reversible specific capacity of 203 mAh g −1 after 200 cycles. Our results demonstrate that the sheetlike composites show remarkable cycling stability, high specific capacity and excellent rate ability, and thus hold promise for commercializing the high-performance electrode materials as the advanced lithium-ion batteries.

  17. A novel method to fabricate discrete porous carbon hemispheres and their electrochemical properties as supercapacitors.

    Science.gov (United States)

    Chen, Jiafu; Lang, Zhanlin; Xu, Qun; Zhang, Jianan; Fu, Jianwei; Chen, Zhimin

    2013-11-07

    A simple and efficient method to produce discrete, hierarchical porous carbon hemispheres (CHs) with high uniformity has been successfully developed by constructing nanoreactors and using low crosslinked poly(styrene-co-divinylbenzene) (P(St-co-DVB)) capsules as precursors. The samples are characterized by scanning and transmission electron microscopy, Fourier transform infrared and Raman spectroscopy, X-ray diffraction, and N2 adsorption and desorption. Considering their application, the cyclic voltammetry and electrochemical impedance spectroscopy characterization are tested. The experimental results show that the achievement of discrete and perfect carbon hemispheres is dependent on the proper amount of DVB in the P(St-co-DVB) capsules, which can contribute to the ideal thickness or mechanical strength of the shells. When the amount of DVB is 35 wt% in the precursors, a high Brunauer-Emmett-Teller surface area of 676 m(2) g(-1) can be obtained for the carbon hemispheres, and the extremely large pore volume of 2.63 cm(3) g(-1) can also be achieved at the same time. The electrochemical test shows the carbon hemispheres have a higher specific capacitance of ca. 83 F g(-1) at 10 mV s(-1), compared to other carbon materials. So this method supplies a platform to extend the fabrication field of carbon materials and supplies more chances for the application of carbon materials including carbon hemispheres that are important components and substrates for supercapacitors.

  18. Large-deformation and high-strength amorphous porous carbon nanospheres

    Science.gov (United States)

    Yang, Weizhu; Mao, Shimin; Yang, Jia; Shang, Tao; Song, Hongguang; Mabon, James; Swiech, Wacek; Vance, John R.; Yue, Zhufeng; Dillon, Shen J.; Xu, Hangxun; Xu, Baoxing

    2016-04-01

    Carbon is one of the most important materials extensively used in industry and our daily life. Crystalline carbon materials such as carbon nanotubes and graphene possess ultrahigh strength and toughness. In contrast, amorphous carbon is known to be very brittle and can sustain little compressive deformation. Inspired by biological shells and honeycomb-like cellular structures in nature, we introduce a class of hybrid structural designs and demonstrate that amorphous porous carbon nanospheres with a thin outer shell can simultaneously achieve high strength and sustain large deformation. The amorphous carbon nanospheres were synthesized via a low-cost, scalable and structure-controllable ultrasonic spray pyrolysis approach using energetic carbon precursors. In situ compression experiments on individual nanospheres show that the amorphous carbon nanospheres with an optimized structure can sustain beyond 50% compressive strain. Both experiments and finite element analyses reveal that the buckling deformation of the outer spherical shell dominates the improvement of strength while the collapse of inner nanoscale pores driven by twisting, rotation, buckling and bending of pore walls contributes to the large deformation.

  19. Control of Partial Coalescence of Self-Assembled Metal Nano-Particles across Lyotropic Liquid Crystals Templates towards Long Range Meso-Porous Metal Frameworks Design

    Directory of Open Access Journals (Sweden)

    Ludovic F. Dumée

    2015-10-01

    Full Text Available The formation of purely metallic meso-porous metal thin films by partial interface coalescence of self-assembled metal nano-particles across aqueous solutions of Pluronics triblock lyotropic liquid crystals is demonstrated for the first time. Small angle X-ray scattering was used to study the influence of the thin film composition and processing conditions on the ordered structures. The structural characteristics of the meso-structures formed demonstrated to primarily rely on the lyotropic liquid crystal properties while the nature of the metal nano-particles used as well as the their diameters were found to affect the ordered structure formation. The impact of the annealing temperature on the nano-particle coalescence and efficiency at removing the templating lyotropic liquid crystals was also analysed. It is demonstrated that the lyotropic liquid crystal is rendered slightly less thermally stable, upon mixing with metal nano-particles and that low annealing temperatures are sufficient to form purely metallic frameworks with average pore size distributions smaller than 500 nm and porosity around 45% with potential application in sensing, catalysis, nanoscale heat exchange, and molecular separation.

  20. Edge-enriched, porous carbon-based, high energy density supercapacitors for hybrid electric vehicles.

    Science.gov (United States)

    Kim, Yong Jung; Yang, Cheol-Min; Park, Ki Chul; Kaneko, Katsumi; Kim, Yoong Ahm; Noguchi, Minoru; Fujino, Takeshi; Oyama, Shigeki; Endo, Morinobu

    2012-03-12

    Supercapacitors can store and deliver energy by a simple charge separation, and thus they could be an attractive option to meet transient high energy density in operating fuel cells and in electric and hybrid electric vehicles. To achieve such requirements, intensive studies have been carried out to improve the volumetric capacitance in supercapacitors using various types and forms of carbons including carbon nanotubes and graphenes. However, conventional porous carbons are not suitable for use as electrode material in supercapacitors for such high energy density applications. Here, we show that edge-enriched porous carbons are the best electrode material for high energy density supercapacitors to be used in vehicles as an auxiliary powertrain. Molten potassium hydroxide penetrates well-aligned graphene layers vertically and consequently generates both suitable pores that are easily accessible to the electrolyte and a large fraction of electrochemically active edge sites. We expect that our findings will motivate further research related to energy storage devices and also environmentally friendly electric vehicles. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Influence of electrolyte ion-solvent interactions on the performances of supercapacitors porous carbon electrodes

    Science.gov (United States)

    Decaux, C.; Matei Ghimbeu, C.; Dahbi, M.; Anouti, M.; Lemordant, D.; Béguin, F.; Vix-Guterl, C.; Raymundo-Piñero, E.

    2014-10-01

    The development of advanced and safe electrochemical supercapacitors or hybrid supercapacitors combining a battery electrode material such as graphite and a porous carbon electrode implies the use of new electrolytes containing a tetra-alkylammonium or lithium salt dissolved preferentially in a safe and environmentally friendly solvent such as alkylcarbonates. In those systems, the carbon porosity of the activated carbon electrode controls the electrochemical behavior of the whole device. In this work, it is demonstrated that electrolytes containing highly polarizing ions such as Li+ dissolved in polar solvents such as alkylcarbonates do not completely loss their solvation shell at the opposite of what is observed for poorly solvated cations like TEABF4. As a consequence, the optimal carbon pore size for obtaining the largest energy density, while keeping a high power density, is wider when strongly solvated cations, like Li+ are used than for conventional organic electrolytes using acetonitrile as solvent and TEA+ as salt cations. TEA+ cations are easily desolvated and hence are able to penetrate in small pores matching the dimensions of bare ions. The dissimilarity of behavior of alkylcarbonates and acetonitrile based electrolytes highlights the importance of ion-solvent interactions when searching the optimal porous texture for the electrode material.

  2. The porous carbon derived from water hyacinth with well-designed hierarchical structure for supercapacitors

    Science.gov (United States)

    Zheng, Kaiwen; Li, Yuanyuan; Zhu, Ming; Yu, Xi; Zhang, Mengyan; Shi, Ling; Cheng, Jue

    2017-10-01

    A hierarchical porous water hyacinth-derived carbon (WHC) is fabricated by pre-carbonization and KOH activation for supercapacitors. The physicochemical properties of WHC are researched by scanning electron microscopy (SEM), N2 adsorption-desorption measurements, X-ray diffraction (XRD), Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). The results indicate that WHC exhibits hierarchical porous structure and high specific surface area of 2276 m2/g. And the electrochemical properties of WHC are studied by cyclic voltammetry (CV), galvanostatic charge-discharge and electrochemical impedance spectroscopy (EIS) tests. In a three-electrode test system, WHC shows considerable specific capacitance of 344.9 F/g at a current density of 0.5 A/g, good rate performance with 225.8 F/g even at a current density of 30 A/g, and good cycle stability with 95% of the capacitance retention after 10000 cycles of charge-discharge at a current density of 5 A/g. Moreover, WHC cell delivers an energy density of 23.8 Wh/kg at 0.5 A/g and a power density of 15.7 kW/kg at 10 A/g. Thus, using water hyacinth as carbon source to fabricate supercapacitors electrodes is a promising approach for developing inexpensive, sustainable and high-performance carbon materials. Additionally, this study supports the sustainable development and the control of biological invasion.

  3. Macroscale porous carbonized polydopamine-modified cotton textile for application as electrode in microbial fuel cells

    Science.gov (United States)

    Zeng, Lizhen; Zhao, Shaofei; He, Miao

    2018-02-01

    The anode material is a crucial factor that significantly affects the cost and performance of microbial fuel cells (MFCs). In this study, a novel macroscale porous, biocompatible, highly conductive and low cost electrode, carbonized polydopamine-modified cotton textile (NC@CCT), is fabricated by using normal cheap waste cotton textiles as raw material via a simple in situ polymerization and carbonization treatment as anode of MFCs. The physical and chemical characterizations show that the macroscale porous and biocompatible NC@CCT electrode is coated by nitrogen-doped carbon nanoparticles and offers a large specific surface area (888.67 m2 g-1) for bacterial cells growth, accordingly greatly increases the loading amount of bacterial cells and facilitates extracellular electron transfer (EET). As a result, the MFC equipped with the NC@CCT anode achieves a maximum power density of 931 ± 61 mW m-2, which is 80.5% higher than that of commercial carbon felt (516 ± 27 mW m-2) anode. Moreover, making full use of the normal cheap waste cotton textiles can greatly reduce the cost of MFCs and the environmental pollution problem.

  4. Polyaniline-coated freestanding porous carbon nanofibers as efficient hybrid electrodes for supercapacitors

    Science.gov (United States)

    Tran, Chau; Singhal, Richa; Lawrence, Daniel; Kalra, Vibha

    2015-10-01

    Three-dimensional, free-standing, hybrid supercapacitor electrodes combining polyaniline (PANI) and porous carbon nanofibers (P-CNFs) were fabricated with the aim to integrate the benefits of both electric double layer capacitors (high power, cyclability) and pseudocapacitors (high energy density). A systematic investigation of three different electropolymerization techniques, namely, potentiodynamic, potentiostatic, and galvanostatic, for electrodeposition of PANI on freestanding carbon nanofiber mats was conducted. It was found that the galvanostatic method, where the current density is kept constant and can be easily controlled facilitates conformal and uniform coating of PANI on three-dimensional carbon nanofiber substrates. The electrochemical tests indicated that the PANI-coated P-CNFs exhibit excellent specific capacitance of 366 F g-1 (vs. 140 F g-1 for uncoated porous carbon nanofibers), 140 F cm-3 volumetric capacitance, and up to 2.3 F cm-2 areal capacitance at 100 mV s-1 scan rate. Such excellent performance is attributed to a thin and conformal coating of PANI achieved using the galvanostatic electrodeposition technique, which not only provides pseudocapacitance with high rate capability, but also retains the double-layer capacitance of the underlying P-CNFs.

  5. Hierarchically Porous N-doped Carbon Derived from ZIF-8 Nanocomposites for Electrochemical Applications

    International Nuclear Information System (INIS)

    Jiang, Min; Cao, Xueping; Zhu, Dandan; Duan, Yongxin; Zhang, Jianming

    2016-01-01

    A core-shell structure composite, zeolitic imidazolate framework @ cetyltrimethylammonium bromide (ZIF-8@CTAB) was synthesized by CTAB micelle controlling the growth of ZIF-8 in aqueous systems. Direct carbonization of ZIF-8@CTAB at a high temperature produced the nitrogen-doped hierarchically porous carbon (named as PC1000@C). In comparison with the carbonization product of pure ZIF-8 (named as PC1000), PC1000@C possesses the higher specific surface area and two-times larger total pore volume. The results from elemental analysis shows the higher N content in PC1000 sample, while X-ray photoelectron spectroscopy curve-fitting shows the higher quaternary-N content in PC1000@C sample. The hierarchical microporous/mesoporous structure, high surface area and favorable N species in PC1000@C play an active role in catalyzing oxygen reduction reaction (ORR). The specific capacitance of porous carbon was calculated from the galvanostatic-discharge curve. PC1000@C exhibits a large specific capacitance of 225 F g"−"1 at a current density of 0.5 A g"−"1 and still retains 92% of initial capacitance after 1000 galvanostatic charge-discharge cycles.

  6. Synthesis and photocatalytic properties of graphitic carbon nitride nanofibers using porous anodic alumina templates

    Science.gov (United States)

    Suchitra, S. M.; Udayashankar, N. K.

    2017-12-01

    In the present study, we describe an effective method for the synthesis of Graphitic carbon nitride (GCN) nanostructures using porous anodic alumina (AAO) membrane as template by simple thermal condensation of cyanamide. Synthesized nanostructure was fully analysed by various techniques to detect its crystalline nature, morphology, luminescent properties followed by the evaluation of its photocatalytic activity in the degradation of Methylene blue dye. Structural analysis of synthesized GCNNF was systematically carried out using x-ray powder diffraction (XRD) and scanning electron microscope (SEM), and. The results confirmed the growth of GCN inside the nanochannels of anodic alumina templates. Luminescent properties of GCNNF were studied using photoluminescence (PL) spectroscopy. PL analysis showed the presence of a strong emission peak in the wavelength range of 350-600 nm in blue region. GCNNF displays higher photocatalytic performance in the photodegradation of methylene blue compare to the bulk GCN. Highlights 1. In the present paper, we report the synthesis of graphitic carbon nitride nanofibers (GCNNF) using porous anodic aluminium oxide membranes as templates through thermal condensation of cyanamide at 500 °C. 2. The synthesis of Graphitic carbon nitride nanofibers using porous andic alumina template is the efficient approach for increasing crystallinity and surface area. 3. The high surface area of graphitic carbon nitride nanofibers has a good impact on novel optical and photocatalytic properties of the bulkGCN. 4. AAO templating of GCN is one of the versatile method to produce tailorable GCN nanostructures with higher surface area and less number of structural defects. 5. Towards photocatalytic degradation of dyes, the tuning of physical properties is very essential thing hence we are succeeded in achieving better catalytic performance of GCN nanostructures by making use of AAO templates.

  7. Storing in carbon nano structures for hybrid systems solar hydrogen

    International Nuclear Information System (INIS)

    Marazzi, R.; Zini, G.; Tartarini, P.

    2009-01-01

    We have developed a hybrid energy system for converting energy from renewable sources and its storage in the form of hydrogen. The storage uses activated carbon and the methodology was modelled mathematically and simulated in numerical software. The results show that storage compression is cheaper storage for liquefaction. [it

  8. Hierarchical porous carbons prepared by an easy one-step carbonization and activation of phenol-formaldehyde resins with high performance for supercapacitors

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Zhoujun [State Key Laboratory of High Performance Ceramics and Superfine Microstructures, Graduate School, Shanghai Institute of Ceramics, Chinese Academy of Science, 1295 Dingxi Road, Shanghai 200050 (China); Gao, Qiuming [State Key Laboratory of High Performance Ceramics and Superfine Microstructures, Graduate School, Shanghai Institute of Ceramics, Chinese Academy of Science, 1295 Dingxi Road, Shanghai 200050 (China); School of Chemistry and Environment, Beihang University, 37 Xueyuan Road, Haidian District, Beijing 100191 (China)

    2011-02-01

    Hierarchical porous carbons are prepared by an easy one-step process of carbonization and activation derived from phenol-formaldehyde resins, in which potassium hydroxide acts as both the catalyst of polymerization and the activation reagent. The simple one-step preparation saves the cost of carbons and leads to high yield. The porous carbons have high surface areas with abundant pore structures. The plenty of micropores and small mesopores increase the capacitance and make the electrolyte ions diffuse fast into the pores. These hierarchical porous carbons show high performance for supercapacitors possessing of the optimized capacitance of 234 F g{sup -1} in aqueous electrolyte and 137 F g{sup -1} in organic electrolyte with high capacitive retention. (author)

  9. Waterproofing of porous carbonate rocks: Efficiency-controlling its properties

    Directory of Open Access Journals (Sweden)

    Esbert, R. M.

    1995-03-01

    Full Text Available The aim of this study is to establish which physical properties may be used, in a routine way, in order to know the efficacy rate of a treatment applied on a specific rocky substrate. Whit this purpose, two types of carbonated rocks, the limestone of Hontoria (Burgos and the dolomite of Laspra (Asturias have been chosen, with a very different configuration of their porosity systems. Three protection products, with silico-organic nature and widely used have been used, to wit: two siloxenes and a copolymer. Tue properties chosen (contact angle and water vapour permeability have been the proper ones in order to determine the efficacy level of the different treatments. This level was demonstrated to be conditioned by the chemical characteristics of this product, and the influence of the characteristics is practically null. Other investigations are being carried out with the same rocks and treatment products in order to establish the corelationships between the efficacy rate of these treatments and the durability of the rock-treatment systems.

    La finalidad del presente estudio es la de tratar de establecer que propiedades físicas pueden ser empleadas de una forma rutinaria para conocer el grado de eficacia de un tratamiento aplicado sobre un determinado sustrato pétreo. Con esta finalidad se han seleccionado dos tipos de rocas carbonatadas, la caliza de Hontoria (Burgos y la dolomía de Laspra (Asturias, con una configuración del sistema poroso muy diferente. Se han empleado tres productos protectores de naturaleza silicoorgánica, ampliamente utilizados, dos siloxanos y un copolímero. Las propiedades seleccionadas (ángulo de contado y permeabilidad al vapor de agua han resultado idóneas para determinar el grado de eficacia de los distintos tratamientos. Se ha comprobado que dicho grado está condicionado por las características químicas del producto, siendo prácticamente nula la influencia de las características de la roca. Se

  10. Microscopic unravelling of nano-carbon doping in MgB{sub 2} superconductors fabricated by diffusion method

    Energy Technology Data Exchange (ETDEWEB)

    Wong, D.C.K. [School of Physics, The University of Sydney, New South Wales 2006 (Australia); Yeoh, W.K. [School of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, New South Wales 2006 (Australia); Australian Centre for Microscopy & Microanalysis, The University of Sydney, New South Wales 2006 (Australia); De Silva, K.S.B. [Institute for Superconducting & Electronic Materials, University of Wollongong, North Wollongong, New South Wales 2500 (Australia); Institute for Nanoscale Technology, Faculty of Science, University of Technology Sydney, Ultimo, New South Wales 2007 (Australia); Kondyurin, A.; Bao, P. [School of Physics, The University of Sydney, New South Wales 2006 (Australia); Li, W.X. [School of Materials Science and Engineering, Shanghai University, Shanghai 200072 (China); Xu, X.; Peleckis, G.; Dou, S.X. [Institute for Superconducting & Electronic Materials, University of Wollongong, North Wollongong, New South Wales 2500 (Australia); Ringer, S.P. [School of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, New South Wales 2006 (Australia); Australian Centre for Microscopy & Microanalysis, The University of Sydney, New South Wales 2006 (Australia); Zheng, R.K., E-mail: rongkun.zheng@sydney.edu.au [School of Physics, The University of Sydney, New South Wales 2006 (Australia)

    2015-09-25

    Highlights: • First report on nano-carbon doped MgB{sub 2} superconductors synthesized by diffusion method. • Microstructure and superconducting properties of the superconductors are discussed. • B{sub 4}C region blocks the Mg from reacting with B in the 10% nano-carbon doped sample. • MgB{sub 2} with 2.5% nano-carbon doped showed the highest J{sub c}, ≈10{sup 4} A/cm{sup 2} for 20 K at 4 T. - Abstract: We investigated the effects of nano-carbon doping as the intrinsic (B-site nano-carbon substitution) and extrinsic (nano-carbon derivatives) pinning by diffusion method. The contraction of the in-plane lattice confirmed the presence of disorder in boron sublattice caused by carbon substitution. The increasing value in full width half maximum (FWHM) in the X-ray diffraction (XRD) patterns with each increment in the doping level reveal smaller grains and imperfect MgB{sub 2} crystalline. The strain increased across the doping level due to the carbon substitution in the MgB{sub 2} matrix. The broadening of the T{sub c} curves from low to high doping showed suppression of the connectivity of the bulk samples with progressive dirtying. At high doping, the presence of B{sub 4}C region blocked the Mg from reacting with crystalline B thus hampering the formation of MgB{sub 2}. Furthermore, the unreacted Mg acted as a current blocking phase in lowering down the grain connectivity hence depressing the J{sub c} of the 10% nano-carbon doped MgB{sub 2} bulk superconductor.

  11. Microscopic unravelling of nano-carbon doping in MgB2 superconductors fabricated by diffusion method

    International Nuclear Information System (INIS)

    Wong, D.C.K.; Yeoh, W.K.; De Silva, K.S.B.; Kondyurin, A.; Bao, P.; Li, W.X.; Xu, X.; Peleckis, G.; Dou, S.X.; Ringer, S.P.; Zheng, R.K.

    2015-01-01

    Highlights: • First report on nano-carbon doped MgB 2 superconductors synthesized by diffusion method. • Microstructure and superconducting properties of the superconductors are discussed. • B 4 C region blocks the Mg from reacting with B in the 10% nano-carbon doped sample. • MgB 2 with 2.5% nano-carbon doped showed the highest J c , ≈10 4 A/cm 2 for 20 K at 4 T. - Abstract: We investigated the effects of nano-carbon doping as the intrinsic (B-site nano-carbon substitution) and extrinsic (nano-carbon derivatives) pinning by diffusion method. The contraction of the in-plane lattice confirmed the presence of disorder in boron sublattice caused by carbon substitution. The increasing value in full width half maximum (FWHM) in the X-ray diffraction (XRD) patterns with each increment in the doping level reveal smaller grains and imperfect MgB 2 crystalline. The strain increased across the doping level due to the carbon substitution in the MgB 2 matrix. The broadening of the T c curves from low to high doping showed suppression of the connectivity of the bulk samples with progressive dirtying. At high doping, the presence of B 4 C region blocked the Mg from reacting with crystalline B thus hampering the formation of MgB 2 . Furthermore, the unreacted Mg acted as a current blocking phase in lowering down the grain connectivity hence depressing the J c of the 10% nano-carbon doped MgB 2 bulk superconductor

  12. Highly Flexible Freestanding Porous Carbon Nanofibers for Electrodes Materials of High-Performance All-Carbon Supercapacitors.

    Science.gov (United States)

    Liu, Ying; Zhou, Jinyuan; Chen, Lulu; Zhang, Peng; Fu, Wenbin; Zhao, Hao; Ma, Yufang; Pan, Xiaojun; Zhang, Zhenxing; Han, Weihua; Xie, Erqing

    2015-10-28

    Highly flexible porous carbon nanofibers (P-CNFs) were fabricated by electrospining technique combining with metal ion-assistant acid corrosion process. The resultant fibers display high conductivity and outstanding mechanical flexibility, whereas little change in their resistance can be observed under repeatedly bending, even to 180°. Further results indicate that the improved flexibility of P-CNFs can be due to the high graphitization degree caused by Co ions. In view of electrode materials for high-performance supercapacitors, this type of porous nanostructure and high graphitization degree could synergistically facilitate the electrolyte ion diffusion and electron transportation. In the three electrodes testing system, the resultant P-CNFs electrodes can exhibit a specific capacitance of 104.5 F g(-1) (0.2 A g(-1)), high rate capability (remain 56.5% at 10 A g(-1)), and capacitance retention of ∼94% after 2000 cycles. Furthermore, the assembled symmetric supercapacitors showed a high flexibility and can deliver an energy density of 3.22 Wh kg(-1) at power density of 600 W kg(-1). This work might open a way to improve the mechanical properties of carbon fibers and suggests that this type of freestanding P-CNFs be used as effective electrode materials for flexible all-carbon supercapacitors.

  13. In Situ One-Step Synthesis of Hierarchical Nitrogen-Doped Porous Carbon for High Performance Supercapacitors

    Energy Technology Data Exchange (ETDEWEB)

    Jeon, Ju Won [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Texas A & M Univ., College Station, TX (United States); Sharma, Ronish [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Meduri, Praveen [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Arey, Bruce W. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Schaef, Herbert T. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Lutkenhaus, Jodie [Texas A & M Univ., College Station, TX (United States); Lemmon, John P. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Thallapally, Praveen K. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Nandasiri, Manjula I. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); McGrail, B. Peter [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Nune, Satish K. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2014-04-30

    Electrochemical performance of the existing state-of-the art capacitors is not very high, key scientific barrier is that its charge storage mechanism wholly depends on adsorption of electrolyte on electrode. We present a novel method for the synthesis of nitrogen -doped porous carbons and address the drawback by precisely controlling composition and surface area. Nitrogen-doped porous carbon was synthesized using a self-sacrificial template technique without any additional nitrogen and carbon sources. They exhibited exceptionally high capacitance (239 Fg-1) due to additional pseudocapacitance originating from doped nitrogen. Cycling tests showed no obvious capacitance decay even after 10,000 cycles, which meets the requirement of commercial supercapacitors. Our method is simple and highly efficient for the production of large quantities of nitrogen-doped porous carbons.

  14. Synthesis of nitrogen-doped porous carbon nanofibers as an efficient electrode material for supercapacitors.

    Science.gov (United States)

    Chen, Li-Feng; Zhang, Xu-Dong; Liang, Hai-Wei; Kong, Mingguang; Guan, Qing-Fang; Chen, Ping; Wu, Zhen-Yu; Yu, Shu-Hong

    2012-08-28

    Supercapacitors (also known as ultracapacitors) are considered to be the most promising approach to meet the pressing requirements of energy storage. Supercapacitive electrode materials, which are closely related to the high-efficiency storage of energy, have provoked more interest. Herein, we present a high-capacity supercapacitor material based on the nitrogen-doped porous carbon nanofibers synthesized by carbonization of macroscopic-scale carbonaceous nanofibers (CNFs) coated with polypyrrole (CNFs@polypyrrole) at an appropriate temperature. The composite nanofibers exhibit a reversible specific capacitance of 202.0 F g(-1) at the current density of 1.0 A g(-1) in 6.0 mol L(-1) aqueous KOH electrolyte, meanwhile maintaining a high-class capacitance retention capability and a maximum power density of 89.57 kW kg(-1). This kind of nitrogen-doped carbon nanofiber represents an alternative promising candidate for an efficient electrode material for supercapacitors.

  15. Hierarchical porous carbon materials derived from petroleum pitch for high-performance supercapacitors

    Science.gov (United States)

    Abudu, Patiman; Wang, Luxiang; Xu, Mengjiao; Jia, Dianzeng; Wang, Xingchao; Jia, Lixia

    2018-06-01

    In this work, a honeycomb-like carbon material derived from petroleum pitch was synthesized by a simple one-step carbonization/activation method using silica nanospheres as the hard templates. The obtained hierarchical porous carbon materials (HPCs) with a large specific surface area and uniform macropore distribution provide abundant active sites and sufficient ion migration channels. When used as an electrode material for supercapacitors, the HPCs exhibit a high specific capacitance of 341.0 F g-1 at 1 A g-1, excellent rate capability with a capacitance retention of 55.6% at 50 A g-1 (189.5 F g-1), and outstanding cycling performance in the three-electrode system.

  16. Nitrogen-doped porous carbon from Camellia oleifera shells with enhanced electrochemical performance

    Energy Technology Data Exchange (ETDEWEB)

    Zhai, Yunbo, E-mail: ybzhai@hnu.edu.cn [College of Environmental Science and Engineering, Hunan University, Changsha 410082 (China); Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha 410082 (China); Xu, Bibo [College of Environmental Science and Engineering, Hunan University, Changsha 410082 (China); Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha 410082 (China); Zhu, Yun [Office of Scientific R& D, Hunan University, Changsha 410082 (China); Qing, Renpeng; Peng, Chuan; Wang, Tengfei; Li, Caiting; Zeng, Guangming [College of Environmental Science and Engineering, Hunan University, Changsha 410082 (China); Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha 410082 (China)

    2016-04-01

    Nitrogen doped porous activated carbon was prepared by annealing treatment of Camellia oleifera shell activated carbon under NH{sub 3}. We found that nitrogen content of activated carbon up to 10.43 at.% when annealed in NH{sub 3} at 800 °C. At 600 °C or above, the N-doped carbon further reacts with NH{sub 3}, leads to a low surface area down to 458 m{sup 2}/g and low graphitization degree. X-ray photoelectron spectroscope (XPS) analysis indicated that the nitrogen functional groups on the nitrogen-doped activated carbons (NACs) were mostly in the form of pyridinic nitrogen. We discovered that the oxygen groups and carbon atoms at the defect and edge sites of graphene play an important role in the reaction, leading to nitrogen atoms incorporated into the lattice of carbon. When temperatures were lower than 600 °C the nitrogen atoms displaced oxygen groups and formed nitrogen function groups, and when temperatures were higher than 600 °C and ~ 4 at.% carbon atoms and part of oxygen function groups reacted with NH{sub 3}. When compared to pure activated carbon, the nitrogen doped activated carbon shows nearly four times the capacitance (191 vs 51 F/g). - Highlights: • The nitrogen content up to 10.43 at % during CAC pyrolysis under NH3 at 800 °C. • The oxygen groups and carbon atoms played an important role in the nitrogen doping. • NAC-600 shows a much higher specific capacitance than CAC.

  17. Synthesis of Carbon Nano tubes Using Anadara Granosa Shells as Catalyst Support

    International Nuclear Information System (INIS)

    Mohd Zobir Hussein; Mohd Zobir Hussein; Salwani Asyikin Zakarya; Siti Halimah Sarijo

    2011-01-01

    The synthesis of carbon nano tubes (CNTs) by chemical vapor deposition (CVD) method using natural calcite prepared from Anadara granosa shells (CS), as metal catalyst support was studied. Hexane and iron were used as carbon precursor and catalyst, respectively. The as synthesised CNTs was characterized using XRD, TEM and FESEM. From the XRD patterns the CNTs peak can be seen more incisive after purification process and from the FESEM micrographs the CNTs can be seen as a bunch of rope-like structures. (author)

  18. Graphene-Like 2D Porous Carbon Nanosheets Derived from Cornstalk Pith for Energy Storage Materials

    Science.gov (United States)

    Gao, Kezheng; Niu, Qingyuan; Tang, Qiheng; Guo, Yaqing; Wang, Lizhen

    2018-01-01

    Biomass materials from different organisms or different parts (even different periods) of the same organism have different microscopic morphologies, hierarchical pore structures and even elemental compositions. Therefore, carbon materials inheriting the unique hierarchical microstructure of different biomass materials may exhibit significantly different electrochemical properties. Cornstalk pith and cornstalk skin (dried by freeze-drying) exhibit significantly different microstructures due to their different biological functions. The cornstalk skin-based carbon (S-carbon) exhibits a thick planar morphology, and the Barrett-Emmett-Teller (BET) surface area is only about 332.07 m2 g-1. However, cornstalk pith-based carbon (P-carbon) exhibits a graphene-like 2D porous nanosheet structure with a rough, wrinkled morphology, and the BET surface area is about 805.17 m2 g-1. In addition, a P-carbon supercapacitor exhibits much higher specific capacitance and much better rate capability than an S-carbon supercapacitor in 6 M potassium hydroxide (KOH) electrolyte.

  19. Manufacture of Methane Hydrate using Carbon Nano Tubes

    International Nuclear Information System (INIS)

    Park, Sung Seek

    2010-02-01

    Methane hydrate is formed by physical binding between water molecule and gas such as methane, ethane, propane, or carbon dioxide, etc., which is captured in the cavities of water molecule under the specific temperature and pressure. More than 99% of naturally produced methane hydrate consists of methane, and is widely dispersed in the continental slope and continental Shelf of the Pacific and the Atlantic, the Antarctica etc. The reserve of fossil fuel is 500 billion carbon ton and the reserve of methane is 360 million carbon ton. The reserve of gas hydrate is more than 1 trillion carbon ton, which is twice the fossil fuel. Therefore, natural gas hydrate as a kind of gas hydrate is expected to replace fossil fuel as new energy source of 21st century. Also 1 m 3 hydrate of pure methane can be decomposed to the maximum of 216 m 3 methane at standard condition. If these characteristics of hydrate are reversely utilized, natural gas is fixed into water in the form of hydrate solid. Therefore, the hydrate is considered to be a great way to transport and store natural gas in large quantity. Especially the transportation cost is known to be 18∼25% less than the liquefied transportation. However, when natural gas hydrate is artificially formed, its reaction time may be too long and the gas consumption in water becomes relatively low, because the reaction rate between water and gas is low. Therefore, for the practical purpose in the application, the present investigation focuses on the rapid production of hydrates and increases gas consumption by adding MWCNT and NaCl into pure water. The results show that the equilibrium pressure in seawater is more higher than that in pure water, and methane hydrate could be formed rapidly during pressurization if the subcooling is maintained at 9K or above in seawater and 8K or above in pure water, respectively. Also, amount of consumed gas volume in pure water is more higher that in seawater at the same experimental conditions

  20. Production of ultra-thin nano-scaled graphene platelets from meso-carbon micro-beads

    Science.gov (United States)

    Zhamu, Aruna; Guo, Jiusheng; Jang, Bor Z

    2014-11-11

    A method of producing nano-scaled graphene platelets (NGPs) having an average thickness no greater than 50 nm, typically less than 2 nm, and, in many cases, no greater than 1 nm. The method comprises (a) intercalating a supply of meso-carbon microbeads (MCMBs) to produce intercalated MCMBs; and (b) exfoliating the intercalated MCMBs at a temperature and a pressure for a sufficient period of time to produce the desired NGPs. Optionally, the exfoliated product may be subjected to a mechanical shearing treatment, such as air milling, air jet milling, ball milling, pressurized fluid milling, rotating-blade grinding, or ultrasonicating. The NGPs are excellent reinforcement fillers for a range of matrix materials to produce nanocomposites. Nano-scaled graphene platelets are much lower-cost alternatives to carbon nano-tubes or carbon nano-fibers.

  1. Synthesis of boron, nitrogen co-doped porous carbon from asphaltene for high-performance supercapacitors

    Science.gov (United States)

    Zhou, Ying; Wang, Dao-Long; Wang, Chun-Lei; Jin, Xin-Xin; Qiu, Jie-Shan

    2014-08-01

    Oxidized asphaltene (OA), a thermosetting material with plenty of functional groups, is synthesized from asphaltene (A) using HNO3/H2SO4 as the oxidizing agent. Boron, nitrogen co-doped porous carbon (BNC—OA) is prepared by carbonization of the mixture of boric acid and OA at 1173 K in an argon atmosphere. X-ray photoelectron spectroscopy (XPS) characterization reveals that the BNC—OA has a nitrogen content of 3.26 at.% and a boron content of 1.31 at.%, while its oxidation-free counterpart (BNC—SA) has a nitrogen content of 1.61 at.% and a boron content of 3.02 at.%. The specific surface area and total pore volume of BNC—OA are 1103 m2·g-1 and 0.921 cm3·g-1, respectively. At a current density of 0.1 A·g-1, the specific capacitance of BNC-OA is 335 F·g-1 and the capacitance retention can still reach 83% at 1 A·g-1. The analysis shows that the superior electrochemical performance of the BNC—OA is attributed to the pseudocapacitance behavior of surface heteroatom functional groups and an abundant pore-structure. Boron, nitrogen co-doped porous carbon is a promising electrode material for supercapacitors.

  2. Porous Carbon with Willow-Leaf-Shaped Pores for High-Performance Supercapacitors.

    Science.gov (United States)

    Shi, Yanhong; Zhang, Linlin; Schon, Tyler B; Li, Huanhuan; Fan, Chaoying; Li, Xiaoying; Wang, Haifeng; Wu, Xinglong; Xie, Haiming; Sun, Haizhu; Seferos, Dwight S; Zhang, Jingping

    2017-12-13

    A novel kind of biomass-derived, high-oxygen-containing carbon material doped with nitrogen that has willow-leaf-shaped pores was synthesized. The obtained carbon material has an exotic hierarchical pore structure composed of bowl-shaped macropores, willow-leaf-shaped pores, and an abundance of micropores. This unique hierarchical porous structure provides an effective combination of high current densities and high capacitance because of a pseudocapacitive component that is afforded by the introduction of nitrogen and oxygen dopants. Our synthetic optimization allows further improvements in the performance of this hierarchical porous carbon (HPC) material by providing a high degree of control over the graphitization degree, specific surface area, and pore volume. As a result, a large specific surface area (1093 m 2 g -1 ) and pore volume (0.8379 cm 3 g -1 ) are obtained for HPC-650, which affords fast ion transport because of its short ion-diffusion pathways. HPC-650 exhibits a high specific capacitance of 312 F g -1 at 1 A g -1 , retaining 76.5% of its capacitance at 20 A g -1 . Moreover, it delivers an energy density of 50.2 W h kg -1 at a power density of 1.19 kW kg -1 , which is sufficient to power a yellow-light-emitting diode and operate a commercial scientific calculator.

  3. Electrochemical performance of porous diamond-like carbon electrodes for sensing hormones, neurotransmitters, and endocrine disruptors.

    Science.gov (United States)

    Silva, Tiago A; Zanin, Hudson; May, Paul W; Corat, Evaldo J; Fatibello-Filho, Orlando

    2014-12-10

    Porous diamond-like carbon (DLC) electrodes have been prepared, and their electrochemical performance was explored. For electrode preparation, a thin DLC film was deposited onto a densely packed forest of highly porous, vertically aligned multiwalled carbon nanotubes (VACNT). DLC deposition caused the tips of the carbon nanotubes to clump together to form a microstructured surface with an enlarged surface area. DLC:VACNT electrodes show fast charge transfer, which is promising for several electrochemical applications, including electroanalysis. DLC:VACNT electrodes were applied to the determination of targeted molecules such as dopamine (DA) and epinephrine (EP), which are neurotransmitters/hormones, and acetaminophen (AC), an endocrine disruptor. Using simple and low-cost techniques, such as cyclic voltammetry, analytical curves in the concentration range from 10 to 100 μmol L(-1) were obtained and excellent analytical parameters achieved, including high analytical sensitivity, good response stability, and low limits of detection of 2.9, 4.5, and 2.3 μmol L(-1) for DA, EP, and AC, respectively.

  4. Preparation and Electrocapacitive Properties of Hierarchical Porous Carbons Based on Loofah Sponge

    Directory of Open Access Journals (Sweden)

    Zichao Li

    2016-11-01

    Full Text Available Four porous carbon samples denoted as LSC-1, LSC-2, LCS-3, and LSC-4 were prepared by carbonization of loofah sponge pretreated by ZnCl2 activation, immersion in N,N-dimethylformamide (DMF, DMF-assisted solvothermal and melamine-assisted hydrothermal processes, and the specific surface areas were 1007, 799, 773, and 538 m2·g−1 with mainly micropores, respectively. Electrocapacitive properties of four porous carbon-based electrodes were investigated with cyclic voltammetry, galvanostatic charge–discharge, and electrochemical impedance spectroscopy in symmetric supercapacitors. All the cyclic voltammetries of four types of supercapacitors showed a rectangular shape, even under a high scan rate of 500 mV·s−1. The capacitances of LSC-1, LSC-2, LSC-3, and LSC-4 were 107.4, 92.5, 60.3, and 82.3 F·g−1 at the current density of 0.1 A·g−1, respectively, and LSC-1 displayed the excellent capacitance retention of about 81.3% with a current density up to 5 A·g−1. All supercapacitors showed excellent electrochemical stability, and the LSC-1-based supercapacitor showed a cycle stability with 92.6% capacitance retention after 5000 cycles at 1 A·g−1. The structure–property relationship of LSC samples is discussed and analyzed on the basis of the experimental data.

  5. Irreversible membrane fouling abatement through pre-deposited layer of hierarchical porous carbons

    KAUST Repository

    Hamad, Juma

    2014-11-01

    In this work, dual-templated hierarchical porous carbons (HPCs), produced from a coupled ice-hard templating approach, are shown to be a highly effective solution to the commonly occurring problem of irreversible fouling of low-pressure membranes used for pre-treatment in wastewater reuse. For the first time, dual-templated HPCs, along with their respective counterparts - single-templated meso-porous carbon (MPCs) (without macropores) - are tested in terms of their fouling reduction capacity and ability to remove different effluent organic matter fractions present in wastewater and compared with a commercially available powdered activated carbon (PAC). The synthesized HPCs provided exceptional fouling abatement, a 4-fold higher fouling reduction as compared to the previously reported best performing commercial PAC and ~2.5-fold better fouling reduction than their respective mesoporous counterpart. Thus, it is shown that not only mesoporosity, but macroporosity is also necessary to achieve high fouling reduction, thus emphasizing the need for dual templating. In the case of HPCs, the pre-deposition technique is also found to outperform the traditional sorbent-feed mixing approach, mainly in terms of removal of fouling components. Based on their superior performance, a high permeability (ultra-low-pressure) membrane consisting of the synthesized HPC pre-deposited on a large pore size membrane support (0.45μm membrane), is shown to give excellent pre-treatment performance for wastewater reuse application. © 2014 Elsevier Ltd.

  6. Natural sisal fibers derived hierarchical porous activated carbon as capacitive material in lithium ion capacitor

    Science.gov (United States)

    Yang, Zhewei; Guo, Huajun; Li, Xinhai; Wang, Zhixing; Yan, Zhiliang; Wang, Yansen

    2016-10-01

    Lithium-ion capacitor (LIC) is a novel advanced electrochemical energy storage (EES) system bridging gap between lithium ion battery (LIB) and electrochemical capacitor (ECC). In this work, we report that sisal fiber activated carbon (SFAC) was synthesized by hydrothermal treatment followed by KOH activation and served as capacitive material in LIC for the first time. Different particle structure, morphology, specific surface area and heteroatoms affected the electrochemical performance of as-prepared materials and corresponding LICs. When the mass ratio of KOH to char precursor was 2, hierarchical porous structured SFAC-2 was prepared and exhibited moderate specific capacitance (103 F g-1 at 0.1 A g-1), superior rate capability and cyclic stability (88% capacity retention after 5000 cycles at 1 A g-1). The corresponding assembled LIC (LIC-SC2) with optimal comprehensive electrochemical performance, displayed the energy density of 83 Wh kg-1, the power density of 5718 W kg-1 and superior cyclic stability (92% energy density retention after 1000 cycles at 0.5 A g-1). It is worthwhile that the source for activated carbon is a natural and renewable one and the synthesis method is eco-friendly, which facilitate that hierarchical porous activated carbon has potential applications in the field of LIC and other energy storage systems.

  7. A photocatalytic approach in micro arc oxidation of WO3-TiO2 nano porous semiconductors under pulse current

    International Nuclear Information System (INIS)

    Bayati, M.R.; Golestani-Fard, F.; Moshfegh, A.Z.; Molaei, R.

    2011-01-01

    Graphical abstract: WO3-TiO2 layers were fabricated via microarc oxidation process and effect of the electrical current type on their photocatalytic performance under UV and visible illuminations was investigated. Highlights: → WO3-TiO2 layers were grown by MAO under pulse current for the first time. → Effect of the frequency and duty cycle on properties of the layers was studied. → A correlation between catalytic performance and growth conditions was proposed. - Abstract: Since ultraviolet (UV) irradiation cannot be applied for a long time in practical applications, it is necessary to develop a narrow band gap photocatalyst to decompose environmental pollutants under visible irradiation. In this research, (WO 3 ) x -(TiO 2 ) 1-x nano-porous layers were fabricated by micro arc oxidation (MAO) and influence of the electrical current type on their physical and chemical properties was investigated. Morphological studies, performed by SEM technique, revealed that pore size and roughness decreased with the frequency and increased with the duty cycle. The pulse-grown layers had a finer structure when compared to those fabricated under direct current. XRD and XPS results showed that the layers consisted of anatase, rutile, and tungsten oxide phases. Applying pulse current resulted in higher anatase relative contents. Band gap energies of the MAO-grown TiO 2 and WO 3 -TiO 2 layers were respectively measured as 3.14 and 2.96 eV. The layers fabricated under pulse current exhibited higher photoactivity under ultraviolet and visible illuminations as compared to the layers grown under direct current. Methylene blue (MB) was used as a model material to examine photocatalytic performance of the layers. Maximum MB-photodegradation reaction rate constants over the pulse-synthesized WO 3 -TiO 2 layers were measured as 0.0269 and 0.0129 min -1 for ultraviolet and visible irradiations. For layers grown under direct current, the rate constants were lower, i.e. 0.0228 and 0

  8. A study on hydrogen storage through adsorption in nano-structured carbons

    International Nuclear Information System (INIS)

    Langohr, D.

    2004-10-01

    The aim of this work is to build and calibrate an experimental set-up for the testing of the materials, to produce some carbon materials in large amounts and characterise them, and finally, to test these materials in their ability to store hydrogen. This will help in establishing a link between the hydrogen storage capacities of the carbons and their nano-structure. The script is divided into four chapters. The first chapter will deal with the literature review on the thematic of hydrogen storage through adsorption in the carbon materials, while the second chapter will present the experimental set-up elaborated in the laboratory. The third chapter explains the processes used to produce the two families of carbon materials and finally, the last chapter presents the structural characterisation of the samples as well as the experimental results of hydrogen storage on the materials elaborated. (author)

  9. Study on the friction and wear properties of carbon fabric composites reinforced with micro- and nano-particles

    International Nuclear Information System (INIS)

    Zhang Zhaozhu; Su Fenghua; Wang Kun; Jiang Wei; Men Xuehu; Liu Weimin

    2005-01-01

    The carbon fabric composites filled with the particulates of polyfluo-150 wax (PFW), nano-particles of ZnO (nano-ZnO), and nano-particles of SiC (nano-SiC), respectively, were prepared by dip-coating of the carbon fabric in a phenolic resin containing the particulates to be incorporated and the successive curing. The friction and wear behaviors of the carbon fabric composites sliding against AISI-1045 steel in a pin-on-disk configuration are evaluated on a Xuanwu-III high-temperature friction and wear tester. The morphologies of the worn surfaces of the filled carbon fabric composites and the counterpart steel pins are analyzed by means of scanning electron microscopy. The effect of the fillers on the adhesion strength of the adhesive is evaluated using a DY35 universal materials tester. It is found that the fillers PFW, nano-ZnO, and nano-SiC contribute to significantly increasing anti-wear abilities of the carbon fabric composites, however, nano-SiC increase the friction coefficient of the carbon fabric composites. The wear rates of the composites at elevated temperature above 180 deg. C are much larger than that below 180 deg. C, which attribute to the degradation and decomposition of the adhesive resin at an excessively elevated temperature. That the interface bonding strength among the carbon fabric, the adhesive, and the particles is significantly increased after solidification and with the transferred film of the varied features largely account for the increased wear-resistance of the filled carbon fabric composites as compared with the unfilled one

  10. Platinum nano-cluster thin film formed on glassy carbon and the application for methanol oxidation

    International Nuclear Information System (INIS)

    Chang, Gang; Oyama, Munetaka; Hirao, Kazuyuki

    2007-01-01

    As an interesting platinum nanostructured material, a Pt nano-cluster film (PtNCF) attached on glassy carbon (GC) is reported. Through the reduction of PtCl 4 2- by ascorbic acid in the presence of GC substrate, a Pt thin continuous film composed of small nano-clusters which had a further agglomerated nanostructure of small grains could be attached on the GC surface. It was found that the electrocatalytic ability of PtNCF for the methanol oxidation was apparently higher than those of the Pt nano-clusters dispersedly attached on GC or indium in oxides. In addition, the electrocatalytic performance of PtNCF per Pt amount was superior to that of Pt black on GC. These results indicate that, in spite of the continuous nanostructures, nano-grains of PtNCF worked effectively for the catalytic electrolysis. The present PtNCF can be regarded as an interesting thin film material, which can be easily prepared by one-step chemical reduction

  11. Hierarchical porous carbon/MnO2 hybrids as supercapacitor electrodes.

    Science.gov (United States)

    Lee, Min Eui; Yun, Young Soo; Jin, Hyoung-Joon

    2014-12-01

    Hybrid electrodes of hierarchical porous carbon (HPC) and manganese oxide (MnO2) were synthesized using a fast surface redox reaction of potassium permanganate under facile immersion methods. The HPC/MnO2 hybrids had a number of micropores and macropores and the MnO2 nanoparticles acted as a pseudocapacitive material. The synergistic effects of electric double-layer capacitor (EDLC)-induced capacitance and pseudocapacitance brought about a better electrochemical performance of the HPC/MnO2 hybrid electrodes compared to that obtained with a single component. The hybrids showed a specific capacitance of 228 F g(-1) and good cycle stability over 1000 cycles.

  12. Rapid Reduction of Alkenes and Alkynes over Pd Nanoparticles Supported on Sulfonated Porous Carbon

    Directory of Open Access Journals (Sweden)

    Arash Shokrolahi

    2013-01-01

    Full Text Available A novel method has been introduced for rapid reduction of alkenes and alkynes, which may be attractive for chemical industries. This method has some advantages such as simplicity and low cost of reactants. Pd supported on sulfonated porous carbon (SPC was used as a new catalyst for reduction of alkenes and alkynes to the corresponding alkanes using sodium borohydride. The heterogeneous reaction was conducted in open air at room temperature to produce the desired saturated compounds in high yields (over 96% and in short reaction time (15 minutes.

  13. Novel hierarchically porous carbon materials obtained from natural biopolymer as host matrixes for lithium-sulfur battery applications.

    Science.gov (United States)

    Zhang, Bin; Xiao, Min; Wang, Shuanjin; Han, Dongmei; Song, Shuqin; Chen, Guohua; Meng, Yuezhong

    2014-08-13

    Novel hierarchically porous carbon materials with very high surface areas, large pore volumes and high electron conductivities were prepared from silk cocoon by carbonization with KOH activation. The prepared novel porous carbon-encapsulated sulfur composites were fabricated by a simple melting process and used as cathodes for lithium sulfur batteries. Because of the large surface area and hierarchically porous structure of the carbon material, soluble polysulfide intermediates can be trapped within the cathode and the volume expansion can be alleviated effectively. Moreover, the electron transport properties of the carbon materials can provide an electron conductive network and promote the utilization rate of sulfur in cathode. The prepared carbon-sulfur composite exhibited a high specific capacity and excellent cycle stability. The results show a high initial discharge capacity of 1443 mAh g(-1) and retain 804 mAh g(-1) after 80 discharge/charge cycles at a rate of 0.5 C. A Coulombic efficiency retained up to 92% after 80 cycles. The prepared hierarchically porous carbon materials were proven to be an effective host matrix for sulfur encapsulation to improve the sulfur utilization rate and restrain the dissolution of polysulfides into lithium-sulfur battery electrolytes.

  14. Carbon dioxide/brine wettability of porous sandstone versus solid quartz: An experimental and theoretical investigation.

    Science.gov (United States)

    Alnili, Firas; Al-Yaseri, Ahmed; Roshan, Hamid; Rahman, Taufiq; Verall, Michael; Lebedev, Maxim; Sarmadivaleh, Mohammad; Iglauer, Stefan; Barifcani, Ahmed

    2018-08-15

    Wettability plays an important role in underground geological storage of carbon dioxide because the fluid flow and distribution mechanism within porous media is controlled by this phenomenon. CO 2 pressure, temperature, brine composition, and mineral type have significant effects on wettability. Despite past research on this subject, the factors that control the wettability variation for CO 2 /water/minerals, particularly the effects of pores in the porous substrate on the contact angle at different pressures, temperatures, and salinities, as well as the physical processes involved are not fully understood. We measured the contact angle of deionised water and brine/CO 2 /porous sandstone samples at different pressures, temperatures, and salinities. Then, we compared the results with those of pure quartz. Finally, we developed a physical model to explain the observed phenomena. The measured contact angle of sandstone was systematically greater than that of pure quartz because of the pores present in sandstone. Moreover, the effect of pressure and temperature on the contact angle of sandstone was similar to that of pure quartz. The results showed that the contact angle increases with increase in temperature and pressure and decreases with increase in salinity. Copyright © 2018 Elsevier Inc. All rights reserved.

  15. Simulating dispersion in porous media and the influence of segmentation on stagnancy in carbonates

    Science.gov (United States)

    Gray, F.; Cen, J.; Shah, S. M.; Crawshaw, J. P.; Boek, E. S.

    2016-11-01

    Understanding the transport of chemical components in porous media is fundamentally important to many reservoir processes such as contaminant transport and reactive flows involved in CO2 sequestration. Carbonate rocks in particular present difficulties for pore-scale simulations because they contain large amounts of sub-micron porosity. In this work, we introduce a new hybrid simulation model to calculate hydrodynamic dispersion in pore-scale images of real porous media and use this to elucidate the origins and behaviour of stagnant zones arising in transport simulations using micro-CT images of carbonates. For this purpose a stochastic particle model for simulating the transport of a solute is coupled to a Lattice-Boltzmann algorithm to calculate the flow field. The particle method incorporates second order spatial and temporal resolution to resolve finer features of the domain. We demonstrate how dispersion coefficients can be accurately obtained in capillaries, where corresponding analytical solutions are available, even when these are resolved to just a few lattice units. Then we compute molecular displacement distributions for pore-spaces of varying complexity: a pack of beads; a Bentheimer sandstone; and a Portland carbonate. Our calculated propagator distributions are compared directly with recent experimental PFG-NMR propagator distributions (Scheven et al., 2005; Mitchell et al., 2008), the latter excluding spin relaxation mechanisms. We observe that the calculated transport propagators can be quantitatively compared with the experimental distribution, provided that spin relaxations in the experiment are excluded, and good agreement is found for both the sandstone and the carbonate. However, due to the absence of explicit micro-porosity from the carbonate pore space image used for flow field simulations we note that there are fundamental differences in the physical origins of the stagnant zones for micro-porous rocks between simulation and experiment. We

  16. Synthesis of Hierarchically Porous Sandwich-Like Carbon Materials for High-Performance Supercapacitors.

    Science.gov (United States)

    Li, Yiju; Chen, Chaoji; Gao, Tingting; Zhang, Dongming; Huang, Xiaomei; Pan, Yue; Ye, Ke; Cheng, Kui; Cao, Dianxue; Wang, Guiling

    2016-11-14

    For the first time, hierarchically porous carbon materials with a sandwich-like structure are synthesized through a facile and efficient tri-template approach. The hierarchically porous microstructures consist of abundant macropores and numerous micropores embedded into the crosslinked mesoporous walls. As a result, the obtained carbon material with a unique sandwich-like structure has a relatively high specific surface (1235 m 2  g -1 ), large pore volume (1.30 cm 3  g -1 ), and appropriate pore size distribution. These merits lead to a comparably high specific capacitance of 274.8 F g -1 at 0.2 A g -1 and satisfying rate performance (87.7 % retention from 1 to 20 A g -1 ). More importantly, the symmetric supercapacitor with two identical as-prepared carbon samples shows a superior energy density of 18.47 Wh kg -1 at a power density of 179.9 W kg -1 . The asymmetric supercapacitor based on as-obtained carbon sample and its composite with manganese dioxide (MnO 2 ) can reach up to an energy density of 25.93 Wh kg -1 at a power density of 199.9 W kg -1 . Therefore, these unique carbon material open a promising prospect for future development and utilization in the field of energy storage. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Interaction of carbon nano tubes with DNA segments

    International Nuclear Information System (INIS)

    Peressinotto, Valdirene Sullas Teixeira

    2007-01-01

    Single- and double-stranded DNA (deoxyribonucleic acid) molecules can strongly bind to single-walled carbon nanotubes (SWNT) via non-covalent interactions. Under certain conditions, the DNA molecule spontaneously self-assembles into a helical wrapping around the tubular structure of the carbon nanotubes to form DNA/SWNT hybrids, which are both stable and soluble in water. This system has recently received extensive attention, since, besides rendering SWNTs dispersible in water as individual tubes, the DNA hybrids are very promising candidates for many applications in nanotechnology and molecular biology. All the possible applications for DNA-SWNT hybrids require, however, a fully understanding of DNA-nanotube wrapping mechanism which is still lacking in the literature. In this context, the aim of this work was to investigate the non-covalent interaction in aqueous medium between SWNTs and synthetic DNA segments having a known nucleotide sequence. Initially, the study was focused on poly d(GT)n sequences (n = 10, 30 and 45) that contain a sequence of alternating guanine and thymine bases and for which the efficiency to disperse and separate carbon nanotubes has already been demonstrated. Besides the size of GT sequences, the effects of ionic strength and pH in the interaction were also investigated. Afterwards, we studied the interaction of SWNT with DNA molecules that contain only a single type of nitrogenous base (DNA homopolymers), which has not been reported in details in the literature. We investigated homopolymers of poly dA 20 , poly dT 20 , poly dC 20 and the duplex poly dA 20 :dT 20 . Most of the study was carried out with small-diameter HiPco SWNTs (with diameters between 0.7 and 1.2 nm). In some studies, SWNTs with diameter around 1.4 nm, synthesized via laser ablation and arc-discharge methods, were also investigated. The arc-discharge nanotubes used in this study were functionalized with carboxylic groups (-COOH) due to their purification using strong

  18. Ion induced transformation of polymer films into diamond-like carbon incorporating silver nano particles

    International Nuclear Information System (INIS)

    Schwarz, Florian P.

    2010-01-01

    Silver containing diamond-like carbon (DLC) is an interesting material for medical engineering from several points of view. On the one hand DLC provides high mechanical robustness. It can be used as biocompatible and wear resistant coating for joint replacing implants. On the other hand silver has antimicrobial properties, which could reduce post-operative inflammations. However conventional production of Ag-DLC by co-deposition of silver and carbon in a plasma process is problematic since it does not allow for a separate control of nano particle morphology and matrix properties. In this work an alternative production method has been developed to circumvent this problem. In metall-DLC-production by ion implantation into a nano composite, silver nano particles are initially formed in solution and then incorporated within a polymer matrix. Finally the polymer is transformed into DLC by ion implantation. The aspects and single steps of this method were investigated with regard to the resulting material's properties. The goal was to design an economically relevant deposition method. Based on experimental results a model of the transformation process has been established, which has also been implemented in a computer simulation. Finally the antibacterial properties of the material have been checked in a biomedical test. Here a bacterial killing rate of 90% could be achieved. (orig.)

  19. Synergy between Printex nano-carbons and silver nanoparticles for sensitive estimation of antioxidant activity

    International Nuclear Information System (INIS)

    Raymundo-Pereira, Paulo A.; Campos, Anderson M.; Prado, Thiago M.; Furini, Leonardo N.; Boas, Naiza V.; Calegaro, Marcelo L.; Machado, Sergio A.S.

    2016-01-01

    We report on the synthesis, characterization and applications of a Printex L6 carbon-silver hybrid nanomaterial (PC-Ag), which was obtained using a polyol method. In addition, we also highlight the use of Printex L6 nano-carbon as a much cheaper alternative to the use of carbon nanotubes and graphene. The silver nanoparticles (AgNP) were prepared directly on the surface of the Printex 6L carbon “nanocarbon” material using ethylene glycol as the reducing agent. The hybrid nanomaterial was characterized by High-angle annular dark-field transmission electron microscopy (HAADF-TEM), energy–dispersive X-ray spectroscopy (EDX), selected area electron diffraction (SAED), Raman spectroscopy and cyclic voltammetry. Optimized electrocatalytic activity on glassy carbon electrode was reached for the architecture GC/PC-Ag, the silver nanoparticles with size ranging between 1 and 2 nm were well–distributed throughout the hybrid material. The synergy between PC nano-carbons and AgNPs was verified by detection of gallic acid (GA) at a low applied potential (0.091 V vs. Ag/AgCl). GA detection was performed in a concentration range between 5.0 × 10"−"7 and 8.5 × 10"−"6 mol L"−"1, with a detection limit of 6.63 × 10"−"8 mol L"−"1 (66.3 nmol L"−"1), which is considerably lower than similar devices. The approach for fabricating the reproducible GC/PC-Ag electrodes is entirely generic and may be explored for other types of (bio)sensors and devices. - Highlights: • We highlight the use of Printex L6 nano-carbon as a much cheaper alternative to carbon nanotubes and graphene. • The hybrid nanomaterial was completely characterized by MET, EDX, SAED, DRX, RAMAN and cyclic voltammetry. • The silver nanoparticles (size range 1-2 nm) were prepared directly onto the surface of the Printex 6L Carbon “nanocarbon”. • An ultrathin film PC-AgNP nanostructured showed a synergetic effect between PC nanocarbons and AgNP. • Sensitive estimation of

  20. Synergy between Printex nano-carbons and silver nanoparticles for sensitive estimation of antioxidant activity

    Energy Technology Data Exchange (ETDEWEB)

    Raymundo-Pereira, Paulo A., E-mail: pauloaugustoraymundopereira@gmail.com [Instituto de Química de São Carlos, Universidade de São Paulo, São Carlos, São Paulo, CEP 13566-590 (Brazil); Campos, Anderson M.; Prado, Thiago M. [Instituto de Química de São Carlos, Universidade de São Paulo, São Carlos, São Paulo, CEP 13566-590 (Brazil); Furini, Leonardo N. [Faculdade de Ciências e Tecnologia, UNESP Univ Estadual Paulista, 19060-900 Presidente Prudente, São Paulo (Brazil); Boas, Naiza V.; Calegaro, Marcelo L.; Machado, Sergio A.S. [Instituto de Química de São Carlos, Universidade de São Paulo, São Carlos, São Paulo, CEP 13566-590 (Brazil)

    2016-07-05

    We report on the synthesis, characterization and applications of a Printex L6 carbon-silver hybrid nanomaterial (PC-Ag), which was obtained using a polyol method. In addition, we also highlight the use of Printex L6 nano-carbon as a much cheaper alternative to the use of carbon nanotubes and graphene. The silver nanoparticles (AgNP) were prepared directly on the surface of the Printex 6L carbon “nanocarbon” material using ethylene glycol as the reducing agent. The hybrid nanomaterial was characterized by High-angle annular dark-field transmission electron microscopy (HAADF-TEM), energy–dispersive X-ray spectroscopy (EDX), selected area electron diffraction (SAED), Raman spectroscopy and cyclic voltammetry. Optimized electrocatalytic activity on glassy carbon electrode was reached for the architecture GC/PC-Ag, the silver nanoparticles with size ranging between 1 and 2 nm were well–distributed throughout the hybrid material. The synergy between PC nano-carbons and AgNPs was verified by detection of gallic acid (GA) at a low applied potential (0.091 V vs. Ag/AgCl). GA detection was performed in a concentration range between 5.0 × 10{sup −7} and 8.5 × 10{sup −6} mol L{sup −1}, with a detection limit of 6.63 × 10{sup −8} mol L{sup −1} (66.3 nmol L{sup −1}), which is considerably lower than similar devices. The approach for fabricating the reproducible GC/PC-Ag electrodes is entirely generic and may be explored for other types of (bio)sensors and devices. - Highlights: • We highlight the use of Printex L6 nano-carbon as a much cheaper alternative to carbon nanotubes and graphene. • The hybrid nanomaterial was completely characterized by MET, EDX, SAED, DRX, RAMAN and cyclic voltammetry. • The silver nanoparticles (size range 1-2 nm) were prepared directly onto the surface of the Printex 6L Carbon “nanocarbon”. • An ultrathin film PC-AgNP nanostructured showed a synergetic effect between PC nanocarbons and AgNP.

  1. Fast Conversion of Ionic Liquids and Poly(Ionic Liquid)s into Porous Nitrogen-Doped Carbons in Air.

    Science.gov (United States)

    Men, Yongjun; Ambrogi, Martina; Han, Baohang; Yuan, Jiayin

    2016-04-08

    Ionic liquids and poly(ionic liquid)s have been successfully converted into nitrogen-doped porous carbons with tunable surface area up to 1200 m²/g at high temperatures in air. Compared to conventional carbonization process conducted under inert gas to produce nitrogen-doped carbons, the new production method was completed in a rather shorter time without noble gas protection.

  2. Multi-pulsed intense electron beam emission from velvet, carbon fibers, carbon nano-tubes and dispenser cathodes

    International Nuclear Information System (INIS)

    Xia Liansheng; Yang Anmin; Chen Yi; Zhang Huang; Liu Xingguang; Li Jin; Jiang Xiaoguo; Zhang Kaizhi; Shi Jinshui; Deng Jianjun; Zhang Linwen

    2010-01-01

    The experimental results of studies of four kinds of cathode emitting intense electron beams are demonstrated under multi-pulsed mode based on an experimental setup including two multi-pulse high voltage sources. The tested cathodes include velvet, carbon fibers, carbon nano-tubes (CNTs) and dispenser cathodes. The results indicate that all four are able to emit multi-pulsed beams. For velvet, carbon fiber and CNTs, the electron induced cathode plasma emission may be the main process and this means that there are differences in beam parameters from pulse to pulse. For dispenser cathodes tested in the experiment, although there is a little difference from pulse to pulse for some reason, thermal-electric field emission may be the main process. (authors)

  3. CdS nanoparticles immobilized on porous carbon polyhedrons derived from a metal-organic framework with enhanced visible light photocatalytic activity for antibiotic degradation

    Science.gov (United States)

    Yang, Cao; Cheng, Jianhua; Chen, Yuancai; Hu, Yongyou

    2017-10-01

    The CdS/MOF-derived porous carbon (MPC) composite as an efficient visible-light-driven photocatalyst was prepared through the pyrolysis of ZIF-8 and subsequent growth of CdS. The porous and functionalized MPC enables intimate and discrete growth of CdS nanoparticles. This unique structure not only reduces the bulk recombination owing to nano-size effect of CdS, but also suppresses the surface recombination due to the discrete growth of CdS nanoparticles on MPC polyhedrons, which facilitates electron transfer and charge separation. Moreover, such a composite material possessed good adsorption ability toward the antibiotic pollutants because of the amino-functionalized surface. As a result, the as-prepared CdS/MPC composites showed excellent photocatalytic performance for the antibiotic degradation, significantly improving the photoactivity of CdS. Importantly, the CdS/MPC composite with the CdS loading of 20 wt% exhibited the highest photocatalytic efficiency of approximately 91% and apparent rate constant of 0.024 min-1.

  4. Combined Effect of Surface Nano-Topography and Delivery of Therapeutics on the Adhesion of Tumor Cells on Porous Silicon Substrates

    KAUST Repository

    De Vitis, S.

    2016-02-23

    Porous silicon is a nano material in which pores with different sizes, densities and depths are infiltrated in conventional silicon imparting it augmented properties including biodegradability, biocompatibility, photoluminescence. Here, we realized porous silicon substrates in which the pore size and the fractal dimension were varied over a significant range. We loaded the described substrates with a PtCl(O, O′ − acac)(DMSO) antitumor drug and determined its release profile as a function of pore size over time up to 15 days. We observed that the efficacy of delivery augments with the pore size moving from small (∼ 8nm, efficiency of delivery ∼ 0.2) to large (∼ 55nm, efficiency of delivery ∼ 0.7). Then, we verified the adhesion of MCF-7 breast cancer cells on the described substrates with and without the administration of the antitumor drug. This permitted to decouple and understand the coincidental effects of nano-topography and a controlled dosage of drugs on cell adhesion and growth. While large pore sizes guarantee elevated drug dosages, large fractal dimensions boost cell adhesion on a surface. For the particular case of tumor cells and the delivery of an anti-tumor drug, substrates with a small fractal dimension and large pore size hamper cell growth. The competition between nano-topography and a controlled dosage of drugs may either accelerate or block the adhesion of cells on a nanostructured surface, for applications in tissue engineering, regenerative medicine, personalized lab-on-a-chips, and the rational design of implantable drug delivery systems.

  5. Preparing nano-hole arrays by using porous anodic aluminum oxide nano-structural masks for the enhanced emission from InGaN/GaN blue light-emitting diodes

    International Nuclear Information System (INIS)

    Nguyen, Hoang-Duy; Nguyen, Hieu Pham Trung; Lee, Jae-jin; Mho, Sun-Il

    2012-01-01

    We report on the achievement of the enhanced cathodoluminescence (CL) from InGaN/GaN light-emitting diodes (LEDs) by using roughening surface. Nanoporous anodic aluminum oxide (AAO) mask was utilized to form nano-hole arrays on the surface of InGaN/GaN LEDs. AAO membranes with ordered hexagonal structures were fabricated from aluminum foils by a two-step anodization method. The average pore densities of ∼1.0 × 10 10 cm −2 and 3.0 × 10 10 cm −2 were fabricated with the constant anodization voltages of 25 and 40 V, respectively. Anodic porous alumina film with a thickness of ∼600 nm has been used as a mask for the induced couple plasma etching process to fabricate nano-hole arrays on the LED surface. Diameter and depth of nano-holes can be controlled by varying the etching duration and/or the diameter of AAO membranes. Due to the reduction of total internal reflection obtained in the patterned samples, we have observed that the cathodoluminescence intensity of LEDs with nanoporous structures is increased up to eight times compared to that of samples without using nanoporous structure. (paper)

  6. Preparing nano-hole arrays by using porous anodic aluminum oxide nano-structural masks for the enhanced emission from InGaN/GaN blue light-emitting diodes

    Science.gov (United States)

    Nguyen, Hoang-Duy; Nguyen, Hieu Pham Trung; Lee, Jae-jin; Mho, Sun-Il

    2012-12-01

    We report on the achievement of the enhanced cathodoluminescence (CL) from InGaN/GaN light-emitting diodes (LEDs) by using roughening surface. Nanoporous anodic aluminum oxide (AAO) mask was utilized to form nano-hole arrays on the surface of InGaN/GaN LEDs. AAO membranes with ordered hexagonal structures were fabricated from aluminum foils by a two-step anodization method. The average pore densities of ˜1.0 × 1010 cm-2 and 3.0 × 1010 cm-2 were fabricated with the constant anodization voltages of 25 and 40 V, respectively. Anodic porous alumina film with a thickness of ˜600 nm has been used as a mask for the induced couple plasma etching process to fabricate nano-hole arrays on the LED surface. Diameter and depth of nano-holes can be controlled by varying the etching duration and/or the diameter of AAO membranes. Due to the reduction of total internal reflection obtained in the patterned samples, we have observed that the cathodoluminescence intensity of LEDs with nanoporous structures is increased up to eight times compared to that of samples without using nanoporous structure.

  7. Self-sensing and thermal energy experimental characterization of multifunctional cement-matrix composites with carbon nano-inclusions

    Science.gov (United States)

    D'Alessandro, A.; Pisello, A. L.; Sambuco, Sara; Ubertini, F.; Asdrubali, F.; Materazzi, A. L.; Cotana, F.

    2016-04-01

    The recent progress of Nanotechnology allowed the development of new smart materials in several fields of engineering. In particular, innovative construction materials with multifunctional enhanced properties can be produced. The paper presents an experimental characterization on cement-matrix pastes doped with Carbon Nanotubes, Carbon Nano-fibers, Carbon Black and Graphene Nano-platelets. Both electro-mechanical and thermo-physical investigations have been carried out. The conductive nano-inclusions provide the cementitious matrix with piezo-resistive properties allowing the detection of external strain and stress changes. Thereby, traditional building materials, such as concrete and cementitious materials in general, would be capable of self-monitoring the state of deformation they are subject to, giving rise to diffuse sensing systems of structural integrity. Besides supplying self-sensing abilities, carbon nano-fillers may change mechanical, physical and thermal properties of cementitious composites. The experimental tests of the research have been mainly concentrated on the thermal conductivity and the optical properties of the different nano-modified materials, in order to make a critical comparison between them. The aim of the work is the characterization of an innovative multifunctional composite capable of combining self-monitoring properties with proper mechanical and thermal-energy efficiency characteristics. The potential applications of these nano-modified materials cover a wide range of possibilities, such as structural elements, floors, geothermal piles, radiant systems and more.

  8. Trends in the Microwave-Assisted Synthesis of Metal Oxide Nanoparticles Supported on Carbon Nano tubes and Their Applications

    International Nuclear Information System (INIS)

    Motshekga, S.C.; Pillai, S.K.; Ray, S.S.; Motshekga, S.C.; Ray, S.S.; Jalama, K.; Krause, Rui.W.M.

    2012-01-01

    The study of coating carbon nano tubes with metal/oxides nanoparticles is now becoming a promising and challenging area of research. To optimize the use of carbon nano tubes in various applications, it is necessary to attach functional groups or other nano structures to their surface. The combination of the distinctive properties of carbon nano tubes and metal/oxides is expected to be applied in field emission displays, nano electronic devices, novel catalysts, and polymer or ceramic reinforcement. The synthesis of these composites is still largely based on conventional techniques, such as wet impregnation followed by chemical reduction of the metal nanoparticle precursors. These techniques based on thermal heating can be time consuming and often lack control of particle size and morphology. Hence, there is interest in microwave technology recently, where using microwaves represents an alternative way of power input into chemical reactions through dielectric heating. This paper covers the synthesis and applications of carbon-nano tube-coated metal/oxides nanoparticles prepared by a microwave-assisted method. The reviewed studies show that the microwave-assisted synthesis of the composites allows processes to be completed within a shorter reaction time with uniform and well-dispersed nanoparticle formation.

  9. Porous carbons

    Indian Academy of Sciences (India)

    Sadhana. Current Issue : Vol. 43, Issue 3. Current Issue Volume 43 | Issue 3. March 2018. Home · Volumes & Issues · Special Issues · Search · Editorial Board · Information for Authors · Subscription ...

  10. Electron beam generation and structure of defects in carbon and boron nitride nano-tubes

    Energy Technology Data Exchange (ETDEWEB)

    Zobelli, A

    2007-10-15

    The nature and role of defects is of primary importance to understand the physical properties of C and BN (boron nitride) single walled nano-tubes (SWNTs). Transmission electron microscopy (TEM) is a well known powerful tool to study the structure of defects in materials. However, in the case of SWNTs, the electron irradiation of the TEM may knock out atoms. This effect may alter the native structure of the tube, and has also been proposed as a potential tool for nano-engineering of nano-tubular structures. Here we develop a theoretical description of the irradiation mechanism. First, the anisotropy of the emission energy threshold is obtained via density functional based calculations. Then, we numerically derive the total Mott cross section for different emission sites of carbon and boron nitride nano-tubes with different chiralities. Using a dedicated STEM (Scanning Transmission Electron Microscope) microscope with experimental conditions optimised on the basis of derived cross-sections, we are able to control the generation of defects in nano-tubular systems. Either point or line defects can be obtained with a spatial resolution of a few nanometers. The structure, energetics and electronics of point and line defects in BN systems have been investigated. Stability of mono- and di- vacancy defects in hexagonal boron nitride layers is investigated, and their activation energies and reaction paths for diffusion have been derived using the nudged elastic band method (NEB) combined with density functional based techniques. We demonstrate that the appearance of extended linear defects under electron irradiation is more favorable than a random distribution of point defects and this is due to the existence of preferential sites for atom emission in the presence of pre-existing defects, rather than thermal vacancy nucleation and migration. (author)

  11. Electron beam generation and structure of defects in carbon and boron nitride nano-tubes

    International Nuclear Information System (INIS)

    Zobelli, A.

    2007-10-01

    The nature and role of defects is of primary importance to understand the physical properties of C and BN (boron nitride) single walled nano-tubes (SWNTs). Transmission electron microscopy (TEM) is a well known powerful tool to study the structure of defects in materials. However, in the case of SWNTs, the electron irradiation of the TEM may knock out atoms. This effect may alter the native structure of the tube, and has also been proposed as a potential tool for nano-engineering of nano-tubular structures. Here we develop a theoretical description of the irradiation mechanism. First, the anisotropy of the emission energy threshold is obtained via density functional based calculations. Then, we numerically derive the total Mott cross section for different emission sites of carbon and boron nitride nano-tubes with different chiralities. Using a dedicated STEM (Scanning Transmission Electron Microscope) microscope with experimental conditions optimised on the basis of derived cross-sections, we are able to control the generation of defects in nano-tubular systems. Either point or line defects can be obtained with a spatial resolution of a few nanometers. The structure, energetics and electronics of point and line defects in BN systems have been investigated. Stability of mono- and di- vacancy defects in hexagonal boron nitride layers is investigated, and their activation energies and reaction paths for diffusion have been derived using the nudged elastic band method (NEB) combined with density functional based techniques. We demonstrate that the appearance of extended linear defects under electron irradiation is more favorable than a random distribution of point defects and this is due to the existence of preferential sites for atom emission in the presence of pre-existing defects, rather than thermal vacancy nucleation and migration. (author)

  12. A unified nonlocal strain gradient plate model for nonlinear axial instability of functionally graded porous micro/nano-plates reinforced with graphene platelets

    Science.gov (United States)

    Sahmani, Saeid; Aghdam, Mohammad Mohammadi; Rabczuk, Timon

    2018-04-01

    By gradually changing of the porosity across a specific direction, functionally graded porous materials (FGPMs) are produced which can impart desirable mechanical properties. To enhance these properties, it is common to reinforce FGPMs with nanofillers. The main aim of the current study is to investigate the size-dependent nonlinear axial postbuckling characteristics of FGPM micro/nano-plates reinforced with graphene platelets. For this purpose, the theory of nonlocal strain gradient elasticity incorporating the both stiffness reduction and stiffness enhancement mechanisms of size effects is applied to the refined exponential shear deformation plate theory. Three different patterns of porosity dispersion across the plate thickness in conjunction with the uniform one are assumed for FGPM as an open-cell metal foam is utilized associated with the coefficients of the relative density and porosity. With the aid of the virtual work’s principle, the non-classical governing differential equations are constructed. Thereafter, an improved perturbation technique is employed to capture the size dependencies in the nonlinear load-deflection and load-shortening responses of the reinforced FGPM micro/nano-plates with and without initial geometric imperfection. It is indicated that by increasing the value of porosity coefficient, the size-dependent critical buckling loads of reinforced FGPM micro/nano-plates with all types of porosity dispersion pattern reduce, but the associated shortening may increase or decrease which depends on the type of dispersion pattern.

  13. Hierarchical three-dimensional porous SnS{sub 2}/carbon cloth anode for high-performance lithium ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Chao, Junfeng, E-mail: chchjjff@163.com [College of Electronic Information and Electric Engineering, Anyang Institute of Technology, Anyang 455000 (China); Zhang, Xiutai [College of Electronic Information and Electric Engineering, Anyang Institute of Technology, Anyang 455000 (China); Xing, Shumin [College of Mathematics and Physics, Anyang Institute of Technology, Anyang 455000 (China); Fan, Qiufeng; Yang, Junping; Zhao, Luhua; Li, Xiang [College of Electronic Information and Electric Engineering, Anyang Institute of Technology, Anyang 455000 (China)

    2016-08-15

    Graphical abstract: Hierarchical 3D porous SnS{sub 2}/carbon cloth, good electrochemical performance. - Highlights: • Hierarchical 3D porous SnS{sub 2}/carbon cloth has been firstly synthesized. • The SnS{sub 2}/carbon clothes were good candidates for excellent lithium ion batteries. • The SnS{sub 2}/carbon cloth exhibits improved capacity compared to pure SnS{sub 2}. - Abstract: Hierarchical three-dimension (3D) porous SnS{sub 2}/carbon clothes were synthesized via a facile polyol refluxing process. The as-synthesized samples were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Brunauer–Emmet–Teller (BET) and UV–vis diffuse reflectance spectrometer (UV–vis DRS). The 3D porous SnS{sub 2}/carbon clothes-based lithium ion batteries exhibited high reversible capacity and good rate capability as anode materials. The good electrochemical performance for lithium ion storage could be attributed to the special nanostructure, leading to high-rate transportation of electrolyte ion and electrons throughout the electrode matrix.

  14. Superior performance of nanoscaled Fe3O4 as anode material promoted by mosaicking into porous carbon framework

    Science.gov (United States)

    Wan, Wang; Wang, Chao; Zhang, Weidong; Chen, Jitao; Zhou, Henghui; Zhang, Xinxiang

    2014-01-01

    A nanoscale Fe3O4/porous carbon-multiwalled carbon nanotubes (MWCNTs) composite is synthesized through a simple hard-template method by using Fe2O3 nanoparticles as the precursor and SiO2 nanoparticles as the template. The composite shows good cycle performance (941 mAh g-1 for the first cycle at 0.1 C, with 106% capacity retention at the 80th cycle) and high rate capability (71% capacity retained at 5 C rate). Its excellent electrical properties can be attributed to the porous carbon framework structure, which is composed of carbon and MWCNTs. In this composite, the porous structure provides space for the change in Fe3O4 volume during cycling and shortens the lithium ion diffusion distance, the MWCNTs increase the electron conductivity, and the carbon coating reduces the risk of side reactions. The results provide clear evidences for the utility of porous carbon framework to improve the electrochemical performances of nanosized transition-metal oxides as anode materials for lithium-ion batteries.

  15. Master curves for the sulphur assisted crosslinking reaction of natural rubber in the presence of nano- and nano-structured sp2 carbon allotropes

    Directory of Open Access Journals (Sweden)

    S. Musto

    2017-06-01

    Full Text Available In this paper, master curves are reported for the crosslinking of a diene rubber with a sulphur based system in the presence of either nano- or nano-structured carbon allotropes, such as carbon nanotubes (CNT, a nanosized graphite with high surface area (HSAG and carbon black (CB. Poly(1,4-cis-isoprene from Hevea Brasiliensis was the diene rubber and crosslinking was performed in temperatures ranging from 151 to 180 °C, with carbon allotropes below and above their percolation threshold. Such carbon allotropes were characterized by different aspect ratio, surface area and pH. However, in the crosslinking reaction, they revealed common behaviour. In fact, the specific interfacial area could be used to correlate crosslinking parameters, such as induction time (ts1 and activation energy (Ea calculated by applying the autocatalytic model. Monotonous decrease of ts1 and increase of Ea were observed, with points lying on master curves, regardless of the nature of the carbon allotropes. Remarkable differences were however observed in the structure of the crosslinking network: when the carbon allotrope was above the percolation threshold much larger crosslinking density was obtained in the presence of CNT whereas composites based on HSAG became soluble in hydrocarbon solvent, after the reaction with a thiol. Proposed explanation of these results is based on the reactivity of carbon allotropes with sulphur and sulphur based compounds, demonstrated through the reaction of 1-dodecanethiol and sulphur with CNT and HSAG and with a model substrate such as anthracene.

  16. Nano ZnO-activated carbon composite electrodes for supercapacitors

    Energy Technology Data Exchange (ETDEWEB)

    Selvakumar, M. [Department of Chemistry, Manipal Institute of Technology, Manipal University, Manipal 576 104 (India); Krishna Bhat, D., E-mail: denthajekb@gmail.co [Department of Chemistry, National Institute of Technology Karnataka, Surathkal, Srinivasnagar 575 025 (India); Manish Aggarwal, A.; Prahladh Iyer, S.; Sravani, G. [Department of Chemistry, National Institute of Technology Karnataka, Surathkal, Srinivasnagar 575 025 (India)

    2010-05-01

    A symmetrical (p/p) supercapacitor has been fabricated by making use of nanostructured zinc oxide (ZnO)-activated carbon (AC) composite electrodes for the first time. The composites have been characterized by field emission scanning electron microscopy (FESEM) and X-ray diffraction analysis (XRD). Electrochemical properties of the prepared nanocomposite electrodes and the supercapacitor have been studied using cyclic voltammetry (CV) and AC impedance spectroscopy in 0.1 M Na{sub 2}SO{sub 4} as electrolyte. The ZnO-AC nanocomposite electrode showed a specific capacitance of 160 F/g for 1:1 composition. The specific capacitance of the electrodes decreased with increase in zinc oxide content. Galvanostatic charge-discharge measurements have been done at various current densities, namely 2, 4, 6 and 7 mA/cm{sup 2}. It has been found that the cells have excellent electrochemical reversibility and capacitive characteristics in 0.1 M Na{sub 2}SO{sub 4} electrolyte. It has also been observed that the specific capacitance is constant up to 500 cycles at all current densities.

  17. Nano ZnO-activated carbon composite electrodes for supercapacitors

    Science.gov (United States)

    Selvakumar, M.; Krishna Bhat, D.; Manish Aggarwal, A.; Prahladh Iyer, S.; Sravani, G.

    2010-05-01

    A symmetrical (p/p) supercapacitor has been fabricated by making use of nanostructured zinc oxide (ZnO)-activated carbon (AC) composite electrodes for the first time. The composites have been characterized by field emission scanning electron microscopy (FESEM) and X-ray diffraction analysis (XRD). Electrochemical properties of the prepared nanocomposite electrodes and the supercapacitor have been studied using cyclic voltammetry (CV) and AC impedance spectroscopy in 0.1 M Na 2SO 4 as electrolyte. The ZnO-AC nanocomposite electrode showed a specific capacitance of 160 F/g for 1:1 composition. The specific capacitance of the electrodes decreased with increase in zinc oxide content. Galvanostatic charge-discharge measurements have been done at various current densities, namely 2, 4, 6 and 7 mA/cm 2. It has been found that the cells have excellent electrochemical reversibility and capacitive characteristics in 0.1 M Na 2SO 4 electrolyte. It has also been observed that the specific capacitance is constant up to 500 cycles at all current densities.

  18. Porous carbon with small mesoporesas an ultra-high capacity adsorption medium

    Science.gov (United States)

    Gao, Biaofeng; Zhou, Haitao; Chen, De; Yang, Jianhong

    2017-10-01

    Resins (732-type), abundant and inexpensive resources were used to prepare porous carbon with small mesopores (CSM) by carbonization and post-chemical-activation with potassium hydroxide (KOH). The N2 adsorption measurements revealed that CSM had high surface areas (1776.5 m2 g-1), large pore volumes (1.10 cm3 g-1), and nearly optimal narrow small mesopore sizes ranging from 2 to 7 nm. CSM was used as adsorbent to investigate the adsorption behavior for Rhodamine B (RhB). Due to the optimal pore size distributions (PSD), intensive-stacking interaction, S-doped, and electrostatic attraction, the CSM exhibited an ultra-high-capacity of 1590 mg g-1 for RhB in aqueous solutions.

  19. Feasibility demonstration of consolidating porous beryllium/carbon structures. Final report

    International Nuclear Information System (INIS)

    Browning, M.J.; Hoover, G.E.; Mueller, J.J.; Hanes, H.D.

    1977-01-01

    A preliminary feasibility study was initiated to determine if porous beryllium structures could be fabricated by consolidating beryllium-coated microballoons into a rigid structure. The target specifications were to coat nominally 1-mm diameter microspheres with 0.5-mil beryllium coatings and then bond into a structure. Because of the very short time period, it was agreeable to use existing or quickly-available materials. The general approach was to apply coatings to carbon or quartz microspheres. Physical vapor deposition and ''snow-balling'' of fine beryllium powder were the two methods investigated. Once the particles were coated, HIP (pressure bonding) and pressureless sintering were to be investigated as methods for consolidating the microballoons. A low level of effort was to be spent to look at means of fabricating an all-carbon structure

  20. Fluid flow simulation and permeability computation in deformed porous carbonate grainstones

    Science.gov (United States)

    Zambrano, Miller; Tondi, Emanuele; Mancini, Lucia; Lanzafame, Gabriele; Trias, F. Xavier; Arzilli, Fabio; Materazzi, Marco; Torrieri, Stefano

    2018-05-01

    In deformed porous carbonates, the architecture of the pore network may be modified by deformation or diagenetic processes altering the permeability with respect to the pristine rock. The effects of the pore texture and morphology on permeability in porous rocks have been widely investigated due to the importance during the evaluation of geofluid reservoirs. In this study, these effects are assessed by combining synchrotron X-ray computed microtomography (SR micro-CT) and computational fluid dynamics. The studied samples pertain to deformed porous carbonate grainstones highly affected by deformation bands (DBs) exposed in Northwestern Sicily and Abruzzo regions, Italy. The high-resolution SR micro-CT images of the samples, acquired at the SYRMEP beamline of the Elettra - Sincrotrone Trieste laboratory (Italy), were used for simulating a pressure-driven flow by using the lattice-Boltzmann method (LBM). For the experiments, a multiple relaxation time (MRT) model with the D3Q19 scheme was used to avoid viscosity-dependent results of permeability. The permeability was calculated using Darcy's law once steady conditions were reached. After the simulations, the pore-network properties (effective porosity, specific surface area, and geometrical tortuosity) were calculated using 3D images of the velocity fields. These images were segmented considering a velocity threshold value higher than zero. The study showed that DBs may generate significant heterogeneity and anisotropy of the permeability of the evaluated rock samples. Cataclasis and cementation process taking place within the DBs reduce the effective porosity and therefore the permeability. Contrary to this, pressure dissolution and faulting may generate connected channels which contribute to the permeability only parallel to the DB.

  1. Enhanced Cr(VI) removal by polyethylenimine- and phosphorus-codoped hierarchical porous carbons.

    Science.gov (United States)

    Chen, Shixia; Wang, Jun; Wu, Zeliang; Deng, Qiang; Tu, Wenfeng; Dai, Guiping; Zeng, Zheling; Deng, Shuguang

    2018-08-01

    The amino- and phosphorus-codoped (N,P-codoped) porous carbons derived from oil-tea shells were facilely fabricated through a combination of phosphoric acid (H 3 PO 4 ) activation and amino (polyethylenimine, PEI) modification method. The as-synthesized carbon adsorbents were systematically characterized and evaluated for Cr(VI) removal in aqueous solutions. The relationship between adsorbent properties and adsorption behaviors was illustrated. Moreover, the influences of contact time, initial Cr(VI) concentration, pH, coexisting anions and temperature were also investigated. The adsorption behavior of Cr(VI) could be perfectly described by the pseudo-second-order kinetic model and Sips adsorption model. The maximum adsorption capacity of Cr(VI) on the carbon adsorbents synthesized in this work was 355.0 mg/g, and this excellent Cr(VI) capacity could be sustained with other coexisting anions. In addition to high surface area and suitable pore size distribution, the high Cr(VI) removal capacity is induced by rich heteroatoms incorporation and the Cr(VI) removal mechanism was clearly illustrated. Furthermore, the continuous column breakthrough experiment on obtained N,P-codoped carbon was conducted and well fitted by the Thomas model. This work revealed that PEI modification and P-containing groups could significantly enhance Cr(VI) adsorption capacity and make these N,P-codoped biomass-derived carbons potent adsorbents in practical water treatment applications. Copyright © 2018 Elsevier Inc. All rights reserved.

  2. Porous structure and surface chemistry of phosphoric acid activated carbon from corncob

    Science.gov (United States)

    Sych, N. V.; Trofymenko, S. I.; Poddubnaya, O. I.; Tsyba, M. M.; Sapsay, V. I.; Klymchuk, D. O.; Puziy, A. M.

    2012-11-01

    Active carbons have been prepared from corncob using chemical activation with phosphoric acid at 400 °C using varied ratio of impregnation (RI). Porous structure of carbons was characterized by nitrogen adsorption and scanning electron microscopy. Surface chemistry was studied by IR and potentiometric titration method. It has been shown that porosity development was peaked at RI = 1.0 (SBET = 2081 m2/g, Vtot = 1.1 cm3/g), while maximum amount of acid surface groups was observed at RI = 1.25. Acid surface groups of phosphoric acid activated carbons from corncob includes phosphate and strongly acidic carboxylic (pK = 2.0-2.6), weakly acidic carboxylic (pK = 4.7-5.0), enol/lactone (pK = 6.7-7.4; 8.8-9.4) and phenol (pK = 10.1-10.7). Corncob derived carbons showed high adsorption capacity to copper, especially at low pH. Maximum adsorption of methylene blue and iodine was observed for carbon with most developed porosity (RI = 1.0).

  3. Broccoli-like porous carbon nitride from ZIF-8 and melamine for high performance supercapacitors

    Science.gov (United States)

    Cai, Chenglong; Zou, Yongjin; Xiang, Cuili; Chu, Hailiang; Qiu, Shujun; Sui, Qingli; Xu, Fen; Sun, Lixian; Shah, Afzal

    2018-05-01

    Broccoli-like porous carbon nitride is synthesized by simple one-step carbonization of a composite comprising a Zn-based zeolitic imidazolate framework (ZIF-8) and melamine. The introduction of melamine into the ZIF-8 framework not only increases the N content of the composite and the surface area of the carbonization product, but also induces the formation of a flower-like structure. The carbon obtained from the ZIF-8/melamine composite by the proposed carbonization process at a temperature of 800 °C (ZM-C-800) is found to have a unique three-dimensional broccoli-like shape, a nanoscale size, and an extremely high doping N content (28.3 at.%). These properties substantially improve the electrochemical performance of ZM-C-800, as represented by a high specific capacitance of 359.1 F g-1 at a current density of 1 A g-1, much higher than that of ZIF-8. Furthermore, a symmetric supercapacitor fabricated with two ZM-C-800 electrodes exhibits a power density of 498.5 W kg-1 for an energy density of 11.4 Wh kg-1. This indicates the strong potential of ZM-C-800 for use in the fabrication of energy storage devices.

  4. Three-dimensional porous activated carbon derived from loofah sponge biomass for supercapacitor applications

    Science.gov (United States)

    Su, Xiao-Li; Chen, Jing-Ran; Zheng, Guang-Ping; Yang, Jing-He; Guan, Xin-Xin; Liu, Pu; Zheng, Xiu-Cheng

    2018-04-01

    Biomass carbon source is generally cheap, environmentally friendly and readily available in high quality and quantity. In this work, a series of loofah sponge-derived activated carbon (SAC-x) with hierarchical porous structures are prepared by KOH chemical activation and used as electrode materials for supercapacitors. The pore size can be easily controllable by changing the dosage of KOH. The optimized material (SAC-4) exhibits a high specific capacitance of 309.6 F g-1 at 1 A g-1 in the three-electrode system using 6 M KOH electrolyte. More importantly, the as-assembled symmetric supercapacitor based on SAC-4 exhibits a high energy density of 16.1 Wh kg-1 at a power density of 160.0 W kg-1 using 1 M Na2SO4 electrolyte. These remarkable results demonstrate the exciting commercial potential of SAC-x for high-performance supercapacitor applications due to their high specific surface area, appropriately porous structure, and the trace heteroatom (O and N) functionalities.

  5. Effect of aqueous electrolytes on the electrochemical behaviors of supercapacitors based on hierarchically porous carbons

    Science.gov (United States)

    Zhang, Xiaoyan; Wang, Xianyou; Jiang, Lanlan; Wu, Hao; Wu, Chun; Su, Jingcang

    2012-10-01

    Hierarchically porous carbons (HPCs) have been prepared by sol-gel self-assembly technology with nickel oxide and surfactant as the dual template. The porous carbons are further activated by nitric acid. The electrochemical behaviors of supercapacitors using HPCs as electrode material in different aqueous electrolytes, e.g., (NH4)2SO4, Na2SO4, H2SO4 and KOH are studied by cyclic voltametry, galvanostatic charge/discharge, cyclic life, leakage current, self-discharge and electrochemical impedance spectroscopy. The results demonstrate that the supercapacitors in various electrolytes perform definitely capacitive behaviors; especially in 6 M KOH electrolyte the supercapacitor represents the best electrochemical performance, the shortest relaxation time, and nearly ideal polarisability. The energy density of 8.42 Wh kg-1 and power density of 17.22 kW kg-1 are obtained at the operated voltage window of 1.0 V. Especially, the energy density of 11.54 Wh kg-1 and power density of 10.58 kW kg-1 can be achieved when the voltage is up to 1.2 V.

  6. Ultrathin nickel hydroxide on carbon coated 3D-porous copper structures for high performance supercapacitors.

    Science.gov (United States)

    Kang, Kyeong-Nam; Kim, Ik-Hee; Ramadoss, Ananthakumar; Kim, Sun-I; Yoon, Jong-Chul; Jang, Ji-Hyun

    2018-01-03

    An ultrathin nickel hydroxide layer electrodeposited on a carbon-coated three-dimensional porous copper structure (3D-C/Cu) is suggested as an additive and binder-free conductive electrode with short electron path distances, large electrochemical active sites, and improved structural stability, for high performance supercapacitors. The 3D-porous copper structure (3D-Cu) provides high electrical conductivity and facilitates electron transport between the Ni(OH) 2 active materials and the current collector of the Ni-plate. A carbon coating was applied to the 3D-Cu to prevent the oxidation of Cu, without degrading the electron transport behavior of the 3D-Cu. The 3D-Ni(OH) 2 /C/Cu exhibited a high specific capacitance of 1860 F g -1 at 1 A g -1 , and good cycling performance, with an 86.5% capacitance retention after 10 000 cycles. When tested in a two-electrode system, an asymmetric supercapacitor exhibited an energy density of 147.9 W h kg -1 and a power density of 37.0 kW kg -1 . These results open a new area of ultrahigh-performance supercapacitors, supported by 3D-Cu electrodes.

  7. Highly enhanced adsorption of Congo red by functionalized finger-citron-leaf-based porous carbon.

    Science.gov (United States)

    Zhao, Gui-Hua; Fang, Yao-Yao; Dai, Wei; Ma, Na

    2018-01-01

    A novel high-performance porous carbon material, lanthanum(III)-doped finger-citron-leaf-based porous carbon (La/FPC), has been synthesized and used as an adsorbent for anion dye Congo red (CR). The La/FPC was characterized by nitrogen adsorption and desorption isotherms, scanning electron microscopy, transmission electron microscopy and X-ray photoelectron spectroscopy. The adsorption performance of CR by the FPC and La/FPC composites with different contents of lanthanum(III) were evaluated in fixed-bed breakthrough experiments and batch tests at room temperature (298 K). The La/FPC had a high CR uptake capacity, which was superior to those previously reported for other adsorbents. The La/FPC sorbents can be easily regenerated using an ethanol elution technique, and after five cycles the reused La/FPC maintained about 98% of its original CR adsorption capacity. The adsorption kinetics of CR onto the lanthanum(III)-doped FPCs followed a pseudo-second-order kinetic model and fitted well with a Langmuir adsorption isotherm. La/FPC is a promising adsorbent for the removal of the anionic dyes from wastewater.

  8. Biomass derived nitrogen-doped hierarchical porous carbon sheets for supercapacitors with high performance.

    Science.gov (United States)

    Wang, Cunjing; Wu, Dapeng; Wang, Hongju; Gao, Zhiyong; Xu, Fang; Jiang, Kai

    2018-08-01

    A facile potassium chloride salt-locking technique combined with hydrothermal treatment on precursors was explored to prepare nitrogen-doped hierarchical porous carbon sheets in air from biomass. Benefiting from the effective synthesis strategy, the as-obtained carbon possesses a unique nitrogen-doped thin carbon sheet structure with abundant hierarchical pores and large specific surface areas of 1459 m 2  g -1 . The doped nitrogen in carbon framework has a positive effect on the electrochemical properties of the electrode material, the thin carbon sheet structure benefits for fast ion transfer, the abundant meso-pores provide convenient channels for rapid charge transportation, large specific surface area and lots of micro-pores guarantee sufficient ion-storage sites. Therefore, applied for supercapacitors, the carbon electrode material exhibits an outstanding specific capacitance of 451 F g -1 at 0.5 A g -1 in a three-electrode system. Moreover, the assembled symmetric supercapacitor based on two identical carbon electrodes also displays high specific capacitance of 309 F g -1 at 0.5 A g -1 , excellent rate capacity and remarkable cycling stability with 99.3% of the initial capacitance retention after 10,000 cycles at 5 A -1 . The synthesis strategy avoids expensive inert gas protection and the use of corrosive KOH and toxic ZnCl 2 activated reagents, representing a promising green route to design advanced carbon electrode materials from biomass for high-capacity supercapacitors. Copyright © 2018. Published by Elsevier Inc.

  9. Porous structure and surface chemistry of phosphoric acid activated carbon from corncob

    International Nuclear Information System (INIS)

    Sych, N.V.; Trofymenko, S.I.; Poddubnaya, O.I.; Tsyba, M.M.; Sapsay, V.I.; Klymchuk, D.O.; Puziy, A.M.

    2012-01-01

    Highlights: ► Phosphoric acid activation results in formation of carbons with acidic surface groups. ► Maximum amount of surface groups is introduced at impregnation ratio 1.25. ► Phosphoric acid activated carbons show high capacity to copper. ► Phosphoric acid activated carbons are predominantly microporous. ► Maximum surface area and pore volume achieved at impregnation ratio 1.0. - Abstract: Active carbons have been prepared from corncob using chemical activation with phosphoric acid at 400 °C using varied ratio of impregnation (RI). Porous structure of carbons was characterized by nitrogen adsorption and scanning electron microscopy. Surface chemistry was studied by IR and potentiometric titration method. It has been shown that porosity development was peaked at RI = 1.0 (S BET = 2081 m 2 /g, V tot = 1.1 cm 3 /g), while maximum amount of acid surface groups was observed at RI = 1.25. Acid surface groups of phosphoric acid activated carbons from corncob includes phosphate and strongly acidic carboxylic (pK = 2.0–2.6), weakly acidic carboxylic (pK = 4.7–5.0), enol/lactone (pK = 6.7–7.4; 8.8–9.4) and phenol (pK = 10.1–10.7). Corncob derived carbons showed high adsorption capacity to copper, especially at low pH. Maximum adsorption of methylene blue and iodine was observed for carbon with most developed porosity (RI = 1.0).

  10. Porous structure and surface chemistry of phosphoric acid activated carbon from corncob

    Energy Technology Data Exchange (ETDEWEB)

    Sych, N.V.; Trofymenko, S.I.; Poddubnaya, O.I.; Tsyba, M.M. [Institute for Sorption and Endoecology Problems, National Academy of Sciences of Ukraine, 13 General Naumov St., 03164 Kyiv (Ukraine); Sapsay, V.I.; Klymchuk, D.O. [M.G. Kholodny Institute of Botany, National Academy of Sciences of Ukraine, 2 Tereshchenkivska St., 01601 Kyiv (Ukraine); Puziy, A.M., E-mail: alexander.puziy@ispe.kiev.ua [Institute for Sorption and Endoecology Problems, National Academy of Sciences of Ukraine, 13 General Naumov St., 03164 Kyiv (Ukraine)

    2012-11-15

    Highlights: Black-Right-Pointing-Pointer Phosphoric acid activation results in formation of carbons with acidic surface groups. Black-Right-Pointing-Pointer Maximum amount of surface groups is introduced at impregnation ratio 1.25. Black-Right-Pointing-Pointer Phosphoric acid activated carbons show high capacity to copper. Black-Right-Pointing-Pointer Phosphoric acid activated carbons are predominantly microporous. Black-Right-Pointing-Pointer Maximum surface area and pore volume achieved at impregnation ratio 1.0. - Abstract: Active carbons have been prepared from corncob using chemical activation with phosphoric acid at 400 Degree-Sign C using varied ratio of impregnation (RI). Porous structure of carbons was characterized by nitrogen adsorption and scanning electron microscopy. Surface chemistry was studied by IR and potentiometric titration method. It has been shown that porosity development was peaked at RI = 1.0 (S{sub BET} = 2081 m{sup 2}/g, V{sub tot} = 1.1 cm{sup 3}/g), while maximum amount of acid surface groups was observed at RI = 1.25. Acid surface groups of phosphoric acid activated carbons from corncob includes phosphate and strongly acidic carboxylic (pK = 2.0-2.6), weakly acidic carboxylic (pK = 4.7-5.0), enol/lactone (pK = 6.7-7.4; 8.8-9.4) and phenol (pK = 10.1-10.7). Corncob derived carbons showed high adsorption capacity to copper, especially at low pH. Maximum adsorption of methylene blue and iodine was observed for carbon with most developed porosity (RI = 1.0).

  11. Ion dynamics in porous carbon electrodes in supercapacitors using in situ infrared spectroelectrochemistry.

    Science.gov (United States)

    Richey, Francis W; Dyatkin, Boris; Gogotsi, Yury; Elabd, Yossef A

    2013-08-28

    Electrochemical double layer capacitors (EDLCs), or supercapacitors, rely on electrosorption of ions by porous carbon electrodes and offer a higher power and a longer cyclic lifetime compared to batteries. Ionic liquid (IL) electrolytes can broaden the operating voltage window and increase the energy density of EDLCs. Herein, we present direct measurements of the ion dynamics of 1-ethyl-3-methylimidazolium bis((trifluoromethyl)sulfonyl)imide in an operating EDLC with electrodes composed of porous nanosized carbide-derived carbons (CDCs) and nonporous onion-like carbons (OLCs) with the use of in situ infrared spectroelectrochemistry. For CDC electrodes, IL ions (both cations and anions) were directly observed entering and exiting CDC nanopores during charging and discharging of the EDLC. Conversely, for OLC electrodes, IL ions were observed in close proximity to the OLC surface without any change in the bulk electrolyte concentration during charging and discharging of the EDLC. This provides experimental evidence that charge is stored on the surface of OLCs in OLC EDLCs without long-range ion transport through the bulk electrode. In addition, for CDC EDLCs with mixed electrolytes of IL and propylene carbonate (PC), the IL ions were observed entering and exiting CDC nanopores, while PC entrance into the nanopores was IL concentration dependent. This work provides direct experimental confirmation of EDLC charging mechanisms that previously were restricted to computational simulations and theories. The experimental measurements presented here also provide deep insights into the molecular level transport of IL ions in EDLC electrodes that will impact the design of the electrode materials' structure for electrical energy storage.

  12. Porous media investigation before and after hydrochloric acid injection on a pre-salt carbonate coquinas sample.

    Science.gov (United States)

    Machado, A C; Teles, A P; Pepin, A; Bize-Forest, N; Lima, I; Lopes, R T

    2016-04-01

    Porous space characterization of carbonate rocks is an important aid in petroleum exploration from carbonate reservoir. In this study, X-ray microtomography technique was applied to evaluate total porosity of a coquina sample extracted from pre-salt reservoir, in Brazil, before and after acid injection. Two image processing program were used in order to assess performance. The results showed that microtomography has potential to compute porosity of coquina samples and provides information about rock porous network. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. Synthesis of porous poly(acrylamide hydrogels using calcium carbonate and its application for slow release of potassium nitrate

    Directory of Open Access Journals (Sweden)

    2009-05-01

    Full Text Available Porous poly(acrylamide was synthesized using calcium carbonate microparticles and subsequent acid treatment to remove the calcium carbonate. Methylenebisacrylamide and ammonium persulfate/sodium metabisulfite were used as crosslinking agent and redox initiator, respectively. The porous structure of resulted hydrogels was confirmed using SEM micrographs. The effect of methylenebisacrylamide concentration and calcium carbonate amount on the swelling of the hydrogels was investigated. The results showed that the effect of methylenebisacrylamide and calcium carbonate variables on the swelling is reverse. The hydrogels were subsequently utilized for the loading of potassium nitrate. Potassium nitrate as active agent was loaded into hydrogels and subsequently the release of this active agent was investigated. In these series of investigation, the effect of content of loading, methylenebisacrylamide and calcium carbonate amount on the release of potassium nitrate from hydrogels was investigated.

  14. Nano-hydroxyapatite colloid suspension coated on chemically modified porous silicon by cathodic bias: a suitable surface for cell culture

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez, Alejandra [Escuela de Quimica, Universidad de Costa Rica, 2060 (Co