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Sandrine Berthon-fabry - One of the best experts on this subject based on the ideXlab platform.
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Activity and Durability of Platinum-Based Electrocatalysts with Tin Oxide–Coated Carbon Aerogel Materials as Catalyst Supports
Electrocatalysis, 2019Co-Authors: Fabien Labbe, Tristan Asset, Marian Chatenet, Yasser Ahmad, Katia Guérin, Rudolf Metkemeijer, Sandrine Berthon-fabryAbstract:Platinum nanoparticles were deposited onto Carbon Aerogel with three different tin coatings. The coatings were synthesized at pH = 0.7 or 11.5 and with various masses of SnCl2.H2O precursor: 1, 2, and 10 g. The nanoparticles dispersion was found dependent on the morphological properties of the support, i.e., its specific surface, porosity, and coverage by tin oxide. The material electrochemical activity for the oxygen reduction reaction (ORR) and stability was investigated: two accelerated stress tests (ASTs), mimicking either a base-load cycle procedure (P1) or a start-stop procedure (P2), were performed at T = 80 °C. The sample coated at pH = 0.7 and the sample with the lowest loading, deposited at pH = 11.5, exhibited interesting performances, both in term of stability (under P1) and activity. On the contrary, samples with highly covering tin oxide coating displayed unsatisfactory initial performances, owing to the low electrical conductivity of their catalytic support. In any case, the aging under P2 leads in a dramatic decrease of the electrocatalyst activity. This either resulted from (i) the low degree of organization of the Carbon Aerogel, the latter being prone to harsh corrosion when non-covered by the tin oxide, or (ii) by the chemical changes undergone by the tin oxide during the AST, leading to the formation of an amorphous, low electrical conductivity support.
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Correlations between the catalytic layer composition, the relative humidity and the performance for PEMFC Carbon Aerogel based membrane electrode assemblies
International Journal of Hydrogen Energy, 2014Co-Authors: Mathilde Ouattara-brigaudet, Sandrine Berthon-fabry, Christian Beauger, Patrick AchardAbstract:The parameters influencing the water management or the gas diffusion have a large impact on the performances of the PEMFC. In this work, we focused on the influence of the composition of the cathode catalytic layer on the performance of the MEA in relation to the relative humidity. A Carbon Aerogel was synthesized as catalyst support with a texture minimizing diffusive losses. We studied the influence of the Nafion content by preparing various cathode catalytic layers whose hydric properties were modified by adding PTFE as a hydrophobic agent. We evaluated the impact of the cathodic relative humidity by testing MEAs on a single cell test bench. We showed that modifying the composition of the catalytic layers playing on the content of both Nafion and PTFE, enables to improve the performance due to a better water management. The best performance was obtained with a Nafion/Carbon mass ratio (N/C) of 0.5 and a PTFE/Carbon (PTFE/C) mass ratio of 0.35 allowing 40% more power at 0.4 V and 75%RH. A first positive evaluation of the impact of PTFE is also done with TEC10E40E.
Rashmi Singh - One of the best experts on this subject based on the ideXlab platform.
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Conductivity enhancement of Carbon Aerogel by modified gelation using self additive
2018Co-Authors: Ashish Singh, D.k. Kohli, Rashmi Singh, M. K. Singh, Sushmita Bhartiya, Gaurav Rajak, A.k. KarnalAbstract:Carbon Aerogels having high surface area and open pore structure are being studied for many electrochemical applications such as fuel cells and super capacitors. Moderate electrical conductivity of resorcinol – formaldehyde (R-F) derived Carbon Aerogel limits its utility in these applications. The current manuscript briefs about the synthesis of composite Carbon Aerogel using Carbon Aerogel itself as additive during gelation of water based Carbon Aerogel and study the effect on its conductivity and surface properties. The additive Carbon Aerogel was synthesized and pre-treated at higher temperature to achieve enhancement in conductivity. The composite Carbon Aerogel (CCA) samples were characterized for surface area properties, morphology, electrical conductivity and specific capacitance. The surface area properties of CCA showed improvement and specific surface area of ∼1798 m2/g with total pore volume of 1.7 cm3/g. was obtained. The electrical conductivity of the composite Carbon Aerogel with 5 wt % additive showed improvement over the plain Carbon Aerogel with respective values of 144 S/m and 128 S/m. The specific capacitance evaluated for CA and CCA are 102 and 118 F/g at scan rate of 10mV/s with improvement of ∼16%.
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Facile synthesis of highly conducting and mesoporous Carbon Aerogel as platinum support for PEM fuel cells
International Journal of Hydrogen Energy, 2017Co-Authors: Rashmi Singh, D.k. Kohli, M. K. Singh, Ashish Singh, Sushmita Bhartiya, Prakash C. Ghosh, S. Meenakshi, Prerna GuptaAbstract:Abstract We report novel method for synthesis of Carbon Aerogel as platinum support for PEM fuel cells applications. The sol gel polymerization has been carried out using resorcinol and furfuraldehyde in non-aqueous medium followed by gelation at high pressure. This resulted in highly conducting and mesoporous Carbon Aerogel under ambient drying conditions. Platinum nano-particles are impregnated in the mesoporous Carbon Aerogel using microwave assisted polyol process. The support material and the catalyst are characterized by different analytical techniques like surface area analyzer, X-ray diffraction, transmission electron microscopy and X-ray photoelectron spectroscopy. Cyclic voltammetry and linear sweep voltammetry are used to evaluate the electro–catalytic activity of the Pt/Carbon Aerogel catalyst using rotating disk electrode technique. Well dispersed Pt nano-particles of size ∼3 nm on Carbon Aerogel showed good catalytic activity with onset potential of 964 mV and half wave potential of 814 mV towards oxygen reduction reaction kinetics. A membrane electrode assembly fabricated with the prepared Pt/Carbon Aerogel catalyst as a cathode and anode is tested in PEMFCs (H2 O2) single cell, the power density of 536 mW cm−2 at 0.6 V is obtained at 60 °C under atmospheric pressure.
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Synthesis of platinum nanoparticles on Carbon Aerogel by ambient pressure drying method
Materials Letters, 2010Co-Authors: Rashmi Singh, R.k. Khardekar, D.k. Kohli, Himanshu Srivastava, M. K. Singh, Pradeep Kumar GuptaAbstract:Abstract Platinum nanoparticles were successfully synthesized on porous Carbon Aerogel with narrow pore size distribution by ambient pressure drying method. Platinum doped Carbon Aerogels were synthesized by sol–gel polymerization of resorcinol with furfural in non aqueous medium followed by ambient pressure drying and pyrolysis of organic gel. These samples were characterized by Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), X-ray Diffraction (XRD) and Flow Chemisorption. TEM and XRD results showed that size of platinum nanoparticle varies between 2 and 5 nm depending on platinum loading and pyrolysis temperature. Hydrogen pulsed chemisorption showed 26.5% dispersion of platinum nanoparticles in Carbon Aerogel.
Guohua Zhao - One of the best experts on this subject based on the ideXlab platform.
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three dimensional homogeneous ferrite Carbon Aerogel one pot fabrication and enhanced electro fenton reactivity
ACS Applied Materials & Interfaces, 2013Co-Authors: Yujing Wang, Guohua Zhao, Shouning Chai, Hongying Zhao, Yanbin WangAbstract:This work focuses on constructing a high catalytic activity cathode of an electro-Fenton system, to overcome the defects of low activity, poor stability, and intricate fabrication of supported catalysts. A series of ferrite-Carbon Aerogel (FCA) monoliths with different iron/Carbon ratios was synthesized directly from metal–resin precursors accompanied by phase transformation. Self-doped ferrite nanocrystals and Carbon matrix were formed synchronously via moderate condensation and sol-gel processes, leading to homogeneous texture. An optimal 5% ferric content FCA was composed of coin-like Carbon nano-plate with continuous porous structure, and the ferric particles with diameters of dozens of nanometers were uniformly embedded into the Carbon framework. The FCA exhibited good conductivity, high catalytic efficiency, and distinguished stability. When it was used as an electro-Fenton cathode, metalaxyl degradation results demonstrated that 98% TOC elimination was realized after 4 h, which was 1.5 times higher...
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electro fenton oxidation of pesticides with a novel fe3o4 fe2o3 activated Carbon Aerogel cathode high activity wide ph range and catalytic mechanism
Applied Catalysis B-environmental, 2012Co-Authors: Hongying Zhao, Yujing Wang, Yanbin Wang, Tongcheng Cao, Guohua ZhaoAbstract:Abstract A novel electro-Fenton (E-Fenton) system with the Fe3O4@Fe2O3/activated Carbon Aerogel (ACA) composite cathode was firstly constructed in this study. Its application on degrading imidacloprid exhibited highly catalytic efficiency over a wide applicable pH range from 3 to 9. The removal of imidacloprid and TOC achieved to 90% within 30 and 60 min, respectively. The nature of composite cathode was examined by BJH, XRD, SEM, TEM, XPS and FTIR techniques. ACA with high surface area of 2410 m2 g−1 and multiplicated porosities composed of micropores and mesopores worked not only as cathode but also as Fenton catalyst support, enhancing oxidation activity. We proposed reasonable E-Fenton oxidation mechanisms with Fe3O4@Fe2O3/ACA cathode at acidic and basic conditions. At pH 3, it followed a Haber–Weiss mechanism that the dissolved iron ions and surface Fe(II) sites catalyzed the decomposition of H2O2 to generate hydroxyl radicals ( OH). While at pH 9, it was expected the formation and deactivation of H2O2 complex as well as the catalytic decomposition of H2O2 with surface Fe(III) and Fe(II) sites to produce both superoxide anion ( O2−/HO2 ) and hydroxyl radicals ( OH), involving an in situ recycling of iron oxide (FeO·Fe2O3 → Fe2O3).
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design of a novel cu2o tio2 Carbon Aerogel electrode and its efficient electrosorption assisted visible light photocatalytic degradation of 2 4 6 trichlorophenol
ACS Applied Materials & Interfaces, 2012Co-Authors: Yabo Wang, Guohua Zhao, Yanan Zhang, Hongyi Tian, Huijie Shi, Tianchen ZhouAbstract:Cu2O/TiO2 heterojunction photocatalyst is built on Carbon Aerogel (CA) substrate with good adsorption properties by sol impregnation and seed-mediated synthesis approach. The Cu2O/TiO2/CA electrode has excellent electrosorptive and high efficient photocatalytic properties. Its morphology and surface chemical composition are characterized with SEM, TEM, X-ray diffraction (XRD) and Raman spectra. The UV–vis diffuse reflectance spectra show that the optical absorption edge for Cu2O/TiO2/CA appears at 636 nm. Under visible-light (λ > 420 nm) irradiation, the photocurrent density increment on Cu2O/TiO2/CA is 60 times of that on Cu2O/TiO2/FTO. The electrochemical characteristic is investigated with electrochemical impedance spectrum (EIS). The Cu2O/TiO2/CA electrode is further applied in the electrosorptive photodegradation of the 2,4,6-trichlorophenol (2,4,6-TCP) wastewater. The result shows that the removal ratio of 2,4,6-TCP in 5.5 h on Cu2O/TiO2/CA is 96.3% and the TOC removal is 91.3%. The intermediates ge...
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photocatalysis enhanced electrosorption process for degradation of high concentration dye wastewater on tio2 Carbon Aerogel
Chemical Engineering Journal, 2011Co-Authors: Yuning Jin, Guohua ZhaoAbstract:Abstract TiO 2 /Carbon Aerogel (TiO 2 /CA) electrode was prepared by ambient drying and sol–gel method. Its morphology and surface chemical composition were characterized with SEM, X-ray diffraction (XRD), energy dispersive spectroscopy (EDS) and Raman spectra. The electrosorption characteristics were investigated with N 2 adsorption, electrochemical impedance spectrum (EIS) and physical resistance. The photocatalytic activity of TiO 2 /CA was evaluated by measuring the photocurrent response. The electrode was used in photocatalysis-enhanced electrosorption (PES) treatment of high-concentration (400 mg L −1 ) alizarin red (AR) wastewater. Results revealed that the efficiency in the PES process with TiO 2 /CA electrode was much better than that in traditional electrosorption with CA. In 240 min, AR removal by PES is 97.3%, 3.1 times that of electrosorption. It was found that the in situ photocatalytic regeneration of the adsorbent enhanced the removal capability and stability in treatment of high-concentration wastewater. The degradation intermediates and reaction pathway were also investigated. The AR molecules and intermediates were degraded effectively and mineralized in the PES process. The TOC removal in 240 min was 90.2%.
En Ling Hu - One of the best experts on this subject based on the ideXlab platform.
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Catalytic ozonation of simulated textile dyeing wastewater using mesoporous Carbon Aerogel supported copper oxide catalyst
Journal of Cleaner Production, 2016Co-Authors: En Ling Hu, Song Min Shang, Shou Xiang Jiang, Xiao Ming Tao, Xinbo Wu, Lu GanAbstract:Textile dyeing uses large amount of freshwater and synthetic dyes. Its effluents have to be subjected to certain treatments to remove the contaminants, especially for residue dyestuffs, before discharging to water bodies for elimination of adverse impacts to the environment. The objective of this research is to fabricate a novel catalyst, Carbon Aerogel supported copper oxide, and study its catalytic performance for the first time in ozonation of simulated dyeing wastewater for dye degradation. The catalyst was prepared using sol-gel and impregnation method, and characterized by Transmission Electron Microscope and X-Ray Diffraction techniques which suggesting that the nano-sized copper oxide particles successfully embedded and well-dispersed in the amorphous Carbon Aerogel. The catalytic performance of the catalyst was evaluated by degradation of C.I. Reactive Black 5 in a semi-continuous reactor. The results show that the catalyst has promising potential in ozonation towards dye elimination in dyeing wastewater, in which the dye removal efficiency can be effectively enhanced by the catalyst. In the specific conditions, COD removal could reach 46% in catalytic ozonation system after 60-min reaction, while it was only 29% in ozonation alone without catalyst. In addition, a systematic parameter study was performed to investigate the effect of the temperature, pH, ozone dosage, catalyst amount and dye concentration on dye degradation in terms of color and COD removal.
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Regeneration and reuse of highly polluting textile dyeing effluents through catalytic ozonation with Carbon Aerogel catalysts
Journal of Cleaner Production, 2016Co-Authors: En Ling Hu, Song Min Shang, Shou Xiang Jiang, Xiao Ming Tao, Ka Lok ChiuAbstract:Reactive dyeing of cotton generates a great deal of coloring wastewater containing residual dyes, electrolyte, alkali, and other auxiliaries. Especially for the effluent from the first/initial spent dyeing bath, it may be comprised of as high as 60% of the initial dye dosed, 30–90 g/L of sodium chloride or sodium sulfate, and plenty of sodium Carbonate, making it to be the most contaminative effluent among the entire reactive dyeing process. This paper presents a new alternative to regenerate the waste effluent from the first spent dyeing bath through catalytic ozonation with novel catalysts for reuse of the effluent in successive dyeing. Two novel ozonation catalysts, mesoporous Carbon Aerogel and its supported cobalt oxide nanoparticles, were successfully prepared and used in catalytic degradation of residual dyes in waste effluents with ozone. Degradation efficiency was determined by both decolorization and chemical oxygen demand removal. The result showed novel catalysts could improve both of these two targets. For chemical oxygen demand removal, Carbon Aerogel supported cobalt oxide strikingly enhanced the efficiency by 30% on the whole comparing to ozonation alone (approximately 50%) without the catalyst. Waste effluents after catalytic ozonation were thereafter reused in successive dyeing in the same process. It has been validated that the waste effluent was successfully regenerated and can be additionally reused twice without sacrificing fabric quality, which cannot be realized in ozonation alone. Color difference of the fabric dyed with the regenerated effluent was within the acceptable tolerance, and excellent levelness and equal colorfastness had also been achieved. This is probably the first study to investigate the feasibility of regenerating highly polluting dyeing effluents for reuse by catalytic ozonation with Carbon Aerogel materials. With novel catalysts, it could be speculated that catalytic ozonation is a promising technology for in-situ regeneration of waste effluents in textile dyeing plant for reuse.
Pradeep Kumar Gupta - One of the best experts on this subject based on the ideXlab platform.
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Synthesis of platinum nanoparticles on Carbon Aerogel by ambient pressure drying method
Materials Letters, 2010Co-Authors: Rashmi Singh, R.k. Khardekar, D.k. Kohli, Himanshu Srivastava, M. K. Singh, Pradeep Kumar GuptaAbstract:Abstract Platinum nanoparticles were successfully synthesized on porous Carbon Aerogel with narrow pore size distribution by ambient pressure drying method. Platinum doped Carbon Aerogels were synthesized by sol–gel polymerization of resorcinol with furfural in non aqueous medium followed by ambient pressure drying and pyrolysis of organic gel. These samples were characterized by Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), X-ray Diffraction (XRD) and Flow Chemisorption. TEM and XRD results showed that size of platinum nanoparticle varies between 2 and 5 nm depending on platinum loading and pyrolysis temperature. Hydrogen pulsed chemisorption showed 26.5% dispersion of platinum nanoparticles in Carbon Aerogel.