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Steam activation of Fe-N-C catalyst for advanced power performance of alkaline hydrazine fuel cells
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作者 Sooan Bae Jihyeon Park +3 位作者 Yuna Hwang Jin-Soo Park Jaeyoung Lee Beomgyun Jeong 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2022年第1期276-285,I0008,共11页
Alkaline hydrazine liquid fuel cells(AHFC) have been highlighted in terms of high power performance with non-precious metal catalysts.Although Fe-N-C is a promising non-Pt electrocatalyst for oxygen reduction reaction... Alkaline hydrazine liquid fuel cells(AHFC) have been highlighted in terms of high power performance with non-precious metal catalysts.Although Fe-N-C is a promising non-Pt electrocatalyst for oxygen reduction reaction(ORR),the surface density of the active site is very low and the catalyst layer should be thick to acquire the necessary number of catalytic active sites.With this thick catalyst layer,it is important to have an optimum pore structure for effective reactant conveyance to active sites and an interface structure for faster charge transfer.Herein,we prepare a Fe-N-C catalyst with magnetite particles and hierarchical pore structure by steam activation.The steam activation process significantly improves the power performance of the AHFC as indicated by the lower IR and activation voltage losses.Based on a systematic characterization,we found that hierarchical pore structures improve the catalyst utilization efficiency of the AHFCs,and magnetite nanoparticles act as surface modifiers to reduce the interracial resistance between the electrode and the ion-exchange membrane. 展开更多
关键词 alkaline hydrazine fuel cell Oxygen reduction reaction ELECTROCATALYST Steam activation Ohmic loss Interfacial resistance Surface modifier
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Modified Nitrogen-Doped Graphene Electrocatalyst for Oxygen Reduction Reaction in Alkaline Fuel Cells
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作者 Dureid Qazzazie Michaela Beckert +2 位作者 Rolf Mtilhaupt Olena Yurchenko Gerald Urban 《Journal of Energy and Power Engineering》 2015年第10期886-895,共10页
We report modified nitrogen-doped graphene (CN) as electrocatalyst for ORR (oxygen reduction reaction) in alkaline medium. CN was synthesized by a novel procedure based on graphite oxide thermally treated with cya... We report modified nitrogen-doped graphene (CN) as electrocatalyst for ORR (oxygen reduction reaction) in alkaline medium. CN was synthesized by a novel procedure based on graphite oxide thermally treated with cyanamide suitable for facile N-doping and large-scale production, whereas cyanamide was used as N-precursor. The structure of the material was characterized by TEM (transmission electron microscopy), SEM (scanning electron microscopy), Raman spectroscopy and XPS (X-ray photoelectron spectroscopy). Structural and electrochemical properties of CN were compared with those of non-modified graphene (TRGO (thermally reduced graphite oxide)). The electrochemical characterization of TRGO and CN in alkaline solution demonstrates enhanced electrocatalytic ORR activity and improved long-term stability for N-doped CN. Voltammetric studies confirmed that, oxygen reduction on CN rather follows four-electron pathway. Compared with commercial 20% PtC catalyst, CN is characterized by exceptional methanol crossover resistance and superb long-term operation stability. Owing to these factors, nitrogen-doped graphene has a great potential to be used as metal-free electrocatalyst in cathodes of alkaline fuel cells. 展开更多
关键词 Nitrogen-doped graphene metal-free catalysis oxygen reduction reaction alkaline fuel cells.
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Platinum nanoparticles coated by graphene layers: A low-metal loading catalyst for methanol oxidation in alkaline media 被引量:2
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作者 Camelia Berghian-Grosan Teodora Radu +5 位作者 Alexandru R.Biris Monica Dan Cezara Voice Fumiya Watanabe Alexandru S.Biris Adriana Vulcu 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2020年第1期81-88,I0004,共9页
Platinum catalysts play a major role in the large scale commercialization of direct methanol fuel cells(DMFC).Here,we present a procedure to create a nanostructural graphene-platinum(Gr Pt)composite containing a small... Platinum catalysts play a major role in the large scale commercialization of direct methanol fuel cells(DMFC).Here,we present a procedure to create a nanostructural graphene-platinum(Gr Pt)composite containing a small amount(5.3 wt%)of platinum nanoparticles coated with at least four layers of graphene.The composite,as Gr Pt ink,was deposited on a glassy carbon electrode and its electrocatalytic activity in a methanol oxidation reaction(MOR)was evaluated in a 1 M CH3OH/1 M NaOH solution.The results indicated an enhanced catalytic performance of GrPt towards MOR in alkaline media compared with the Pt/C material.Electron energy-loss spectroscopy and X-ray photoelectron spectroscopy(recorded before and after the electrochemical assays)were employed to analyze the changes in the chemical composition of the nanomaterial and to explain the transformations that took place at the electrode surface.Our findings suggest that growing of graphene on platinum nanoparticles improve the catalytic performance of platinum-graphene composites towards MOR in alkaline media. 展开更多
关键词 Low-platinum loading electrocatalyst Graphene layers Methanol oxidation ELECTROCATALYSIS alkaline fuel cell
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Electrolyte accessibility of non-precious-metal catalysts with different spherical particle sizes under alkaline conditions for oxygen reduction reaction
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作者 Jiyeon Lee Jong Gyeong Kim Chanho Pak 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2021年第1期326-331,I0011,共7页
Fuel cells are one of the most competitive alternative energy sources because their theoretical efficiency is~15%higher than that of internal combustion engines (ICEs) and they are considered cleaner and safer.When fu... Fuel cells are one of the most competitive alternative energy sources because their theoretical efficiency is~15%higher than that of internal combustion engines (ICEs) and they are considered cleaner and safer.When fuel cells are used to replace ICEs in cars and energy conversion systems,the system efficiency increases;furthermore,the process becomes more environmentally-friendly because fuel cells produce electricity by using only hydrogen and oxygen,obtained by purifying atmospheric air by filtering out dust and pollutants.Hence,their final product is only water,instead of pollutants like carboFuel cells are one of the most competitive alternative energy sources because their theoretical efficiency is~15%higher than that of internal combustion engines (ICEs) and they are considered cleaner and safer.When fuel cells are used to replace ICEs in cars and energy conversion systems,the system efficiency increases;furthermore,the process becomes more environmentally-friendly because fuel cells produce electricity by using only hydrogen and oxygen,obtained by purifying atmospheric air by filtering out dust and pollutants.Hence,their final product is only water,instead of pollutants like carbon dioxide.n dioxide. 展开更多
关键词 Non-precious-metal catalyst Oxygen reduction reaction Size effect Electrolyte accessibility alkaline fuel cell
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Activity and Stability of Rare Earth-Based Hydride Alloys as Catalysts of Hydrogen Absorption-Oxidation Reactions
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作者 应桃开 高学平 +1 位作者 胡伟康 Noréus Dag 《Journal of Rare Earths》 SCIE EI CAS CSCD 2004年第6期871-874,共4页
Rare earth-based AB(5)-type hydrogen storage alloys as catalysts of hydrogen-diffusion electrodes for hydrogen absorption and oxidation reactions in alkaline fuel cells were investigated. It is demonstrated that the m... Rare earth-based AB(5)-type hydrogen storage alloys as catalysts of hydrogen-diffusion electrodes for hydrogen absorption and oxidation reactions in alkaline fuel cells were investigated. It is demonstrated that the metahydride hydrogen-diffusion electrodes could be charged by hydrogen gas and electrochemically discharged, at the same time to retain a stable oxidation potential for a long period. The catalytic activities and stability are almost comparable with a Pt catalyst on the active carbon. Further improvement of performances is expected via reduction of catalyst size into nanometers. 展开更多
关键词 inorganic chemistry ELECTROCATALYST alkaline fuel cell hydrogen oxidation rare earths
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Ternary PtRuTe alloy nanofibers as an efficient and durable electrocatalyst for hydrogen oxidation reaction in alkaline media 被引量:4
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作者 Si-Yue Ma Tao Ma +2 位作者 Qi Hu Heng-Pan Yang Chuan-Xin He 《Science China Materials》 SCIE EI CAS CSCD 2022年第12期3462-3469,共8页
Sluggish kinetics of anodic hydrogen oxidation reaction(HOR)in alkaline media,which arises from the two orders of magnitude lower HOR activity in alkali than that in acid media for platinum group metals,hinders the co... Sluggish kinetics of anodic hydrogen oxidation reaction(HOR)in alkaline media,which arises from the two orders of magnitude lower HOR activity in alkali than that in acid media for platinum group metals,hinders the commercial implementation of anion exchange membrane fuel cells(AEMFCs).Consequently,the development of platinum-based catalysts combined with high efficiency and durability is urgently required.Herein,we report a facile route for the synthesis of ternary PtRuTe alloy nanofibers with Pt atomic ratio of only 11%via a simple galvanic replacement reaction.We optimize the adsorption strength of platinum and ruthenium towards hydrogen and hydroxyl species by regulating the electron donation from tellurium to platinum and ruthenium.Hence,the obtained trimetallic alloy catalyst exhibits an impressive kinetic current density of 30.6 mA cm^(−2)_(geo) at 50 mV and an exchange current density of 0.426 mA cm^(−2)_(metal),which shows 3.0-and 2.5-fold enhancement compared with the commercial Pt/C in alkaline electrolyte,respectively.Moreover,the catalyst also demonstrates excellent stability with merely 5%activity attenuation after 2000 potential cycles.This work offers new pathways to boost alkaline HOR by rationally designing multicomponent alloys. 展开更多
关键词 alkaline fuel cells hydrogen oxidation reaction ELECTROCATALYSTS Pt-based alloy NANOFIBERS
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Characterization of different plasma-treated cobalt oxide catalysts for oxygen reduction reaction in alkaline media 被引量:2
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作者 Lisa M.Uhlig Gustav Sievers +2 位作者 Volker Brüser Alexander Dyck Gunther Wittstock 《Science Bulletin》 SCIE EI CAS CSCD 2016年第8期612-618,共7页
Plasma-synthesized cobalt oxide supported on carbon has been analyzed for its use for electrocatalytic oxygen reduction reaction (ORR) in alkaline anion exchange membrane fuel cells (AEMFC). This work presents the... Plasma-synthesized cobalt oxide supported on carbon has been analyzed for its use for electrocatalytic oxygen reduction reaction (ORR) in alkaline anion exchange membrane fuel cells (AEMFC). This work presents the ORR activity in 0.1 mol L-1 KOH and 0.1 tool L-1 K2CO3 at 25 ℃. Cyclic voltammetry (CV) was used to determine the potentials at which the ORR occurs and to evaluate the stability of catalyst. Moreover, a rotating ring-disk electrode (RRDE) was used to investigate the activity of the catalysts and the formation of the by-product hydroperoxide anion (HO2-) as well as to identify the preferred pathway of the ORR. Calculated kinetic parameters for the ORR for the cobalt catalysts are shown in this work together with a comparison to a commercial platinum catalyst. However, the cobalt oxide produced more by-products which could lead to damage of the membrane in a fuel cell through a radical attack of the polymer backbone. 展开更多
关键词 Oxygen reduction reaction alkalinemedia - Electrocatalytic activity RRDE Cobaltcatalyst alkaline fuel cell
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