气候变化领域集成服务门户(CCPortal): The Achilles' heel of iron-based catalysts during oxygen reduction in an acidic medium

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DOI	10.1039/c8ee01855c
	The Achilles' heel of iron-based catalysts during oxygen reduction in an acidic medium
	Choi C.H.; Lim H.-K.; Chung M.W.; Chon G.; Ranjbar Sahraie N.; Altin A.; Sougrati M.-T.; Stievano L.; Oh H.S.; Park E.S.; Luo F.; Strasser P.; Dražić G.; Mayrhofer K.J.J.; Kim H.; Jaouen F.
发表日期	2018
ISSN	17545692
起始页码	3176
结束页码	3182
卷号	11 期号:11
英文摘要	For catalysing dioxygen reduction, iron-nitrogen-carbon (Fe-N-C) materials are today the best candidates to replace platinum in proton-exchange membrane fuel cell (PEMFC) cathodes. Despite tremendous progress in their activity and site-structure understanding, improved durability is critically needed but challenged by insufficient understanding of their degradation mechanisms during operation. Here, we show that FeNxCy moieties in a representative Fe-N-C catalyst are structurally stable but electrochemically unstable when exposed in an acidic medium to H2O2, the main oxygen reduction reaction (ORR) byproduct. We reveal that exposure to H2O2 leaves iron-based catalytic sites untouched but decreases their turnover frequency (TOF) via oxidation of the carbon surface, leading to weakened O2-binding on iron-based sites. Their TOF is recovered upon electrochemical reduction of the carbon surface, demonstrating the proposed deactivation mechanism. Our results reveal for the first time a hitherto unsuspected key deactivation mechanism during the ORR in an acidic medium. This study identifies the N-doped carbon surface as the Achilles' heel during ORR catalysis in PEMFCs. Observed in acidic but not in alkaline electrolytes, these insights suggest that durable Fe-N-C catalysts are within reach for PEMFCs if rational strategies minimizing the amount of H2O2 or reactive oxygen species (ROS) produced during the ORR are developed. © The Royal Society of Chemistry 2018.
英文关键词	Binding sites; Carbon; Catalysts; Catalytic oxidation; Degradation; Doping (additives); Electrolytic reduction; Iron; Iron compounds; Oxygen; Alkaline electrolytes; Deactivation mechanism; Degradation mechanism; Electrochemical reductions; Iron-based catalyst; Oxygen reduction reaction; Reactive oxygen species; Turnover frequency; Proton exchange membrane fuel cells (PEMFC); biodegradation; carbon; catalysis; catalyst; electrochemistry; fuel cell; iron; membrane; nitrogen; oxidation; reactive oxygen species; reduction
语种	英语
来源期刊	Energy & Environmental Science
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/190077
作者单位	School of Materials Science and Engineering, Gwangju Institute of Science and Technology, Gwangju, 61005, South Korea; Department of Chemistry, Graduate School of EEWS, Korea Advanced Institute of Science and Technology, Daejeon, 34141, South Korea; Institut Charles Gerhardt Montpellier, UMR CNRS 5253, Agrégats, Interfaces et Matériaux Pour l'Energie, Université de Montpellier, 34095 Montpellier Cedex 5, France; Department of Interface Chemistry and Surface Engineering, Max-Planck Institut für Eisenforschung GmbH, Max-Planck-Str. 1, Düsseldorf, 40237, Germany; Department of Materials Science and Engineering, Seoul National University, Seoul, 08826, South Korea; Department of Chemistry, Chemical Engineering Division, Technical University Berlin, 10623 Berlin, Germany; Department of Materials Chemistry, National Institute of Chemistry, Hajdrihova 19, Ljubljana, 1001, Slovenia; Helmholtz-Institute Erlangen-Nürnberg for Renewable Energy (IEK-11), Forschungszentrum, Jülich Egerlandstr. 3, Erlangen, 91058, Germ...
推荐引用方式 GB/T 7714	Choi C.H.,Lim H.-K.,Chung M.W.,et al. The Achilles' heel of iron-based catalysts during oxygen reduction in an acidic medium[J],2018,11(11).
APA	Choi C.H..,Lim H.-K..,Chung M.W..,Chon G..,Ranjbar Sahraie N..,...&Jaouen F..(2018).The Achilles' heel of iron-based catalysts during oxygen reduction in an acidic medium.Energy & Environmental Science,11(11).
MLA	Choi C.H.,et al."The Achilles' heel of iron-based catalysts during oxygen reduction in an acidic medium".Energy & Environmental Science 11.11(2018).