气候变化领域集成服务门户(CCPortal): Non-PGM electrocatalysts for PEM fuel cells: Effect of fluorination on the activity and stability of a highly active NC-Ar + NH3 catalyst

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DOI	10.1039/c9ee00867e
	Non-PGM electrocatalysts for PEM fuel cells: Effect of fluorination on the activity and stability of a highly active NC-Ar + NH3 catalyst
	Zhang G.; Yang X.; Dubois M.; Herraiz M.; Chenitz R.; Lefèvre M.; Cherif M.; Vidal F.; Glibin V.P.; Sun S.; Dodelet J.-P.
发表日期	2019
ISSN	1754-5692
起始页码	3015
结束页码	3037
卷号	12 期号:10
英文摘要	In this work, we explore the behavior of our highly active cathode catalyst NC-Ar + NH3 (labeled NC here) before and after fluorination by F2 at room temperature, in order to deepen our understanding of the activity and stability of this highly active catalyst for oxygen electroreduction in H2/air and H2/O2 PEM fuel cells. We discovered that all Fe-based catalytic sites were poisoned by the reaction with F2, even after 2 min of fluorination, and the H2/O2 fuel cell polarization curves of F2-poisoned NC were the same as the polarization curve of MOF-CNx-Ar + NH3, which is a catalyst devoid of Fe, but having the same CNx active sites as those contributing to the NC activity. The F2-poisoned NC catalysts may be partially (∼70%) reactivated by a heat-treatment at 900 °C in Ar, a temperature at which all Fe-Fm bonds of the catalytic sites and all the C-Fp bonds of the NC carbon support are broken. Based on the deconvolution of the XPS N1s spectra recorded for the pristine and fluorinated NC catalysts, we estimated an average turn-over-frequency (ToF) for the FeN4 catalytic sites in H2/O2 fuel cells. ToF of NC ∼ 0.177 ± 0.020 electrons site-1 s-1 at 0.9 V, which is about five times smaller than the ToF for Pt/C at 0.9 V. The stability of pristine and fluorinated NC catalysts has been studied at 0.6 V in H2/air and H2/O2 fuel cells. The instability behavior of fluorinated NC catalysts was found to be similar to that of MOF-CNx-Ar + NH3, but different from that of NC. It is shown that when the catalyst has active FeN4 sites, it is the model proposed by INRS and using the superposition of two exponential decays that better fits the experimental decay, while the Los Alamos autocatalytic model is preferred when there are no Fe-based active sites in the catalyst or if the FeN4 sites are poisoned (e.g., by fluorination as in this work). © 2019 The Royal Society of Chemistry.
语种	英语
scopus关键词	Ammonia; Binary alloys; Electrocatalysts; Electrolytic reduction; Fluorination; Gas fuel purification; Halogenation; Polarization; Proton exchange membrane fuel cells (PEMFC); Stability; Active catalyst; Autocatalytic model; Cathode catalyst; Exponential decays; Fuel cell polarization; Oxygen electro reductions; Polarization curves; Turnover frequency; Catalyst activity; catalysis; catalyst; electrochemical method; electron; fuel cell; hydrogen peroxide; reduction; temperature effect
来源期刊	Energy and Environmental Science
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/162915
作者单位	INRS-Énergie, Matériaux et Télécommunications, 1650 Boulevard Lionel Boulet, Varennes, QC J3X 1S2, Canada; Université Clermont Auvergne, CNRS, SIGMA Clermont, Institut de Chimie de Clermont-Ferrand, Clermont-Ferrand, F-6300, France; Department of Chemical and Biochemical Engineering, University of Western Ontario, London, N6A 5B9, Canada
推荐引用方式 GB/T 7714	Zhang G.,Yang X.,Dubois M.,et al. Non-PGM electrocatalysts for PEM fuel cells: Effect of fluorination on the activity and stability of a highly active NC-Ar + NH3 catalyst[J],2019,12(10).
APA	Zhang G..,Yang X..,Dubois M..,Herraiz M..,Chenitz R..,...&Dodelet J.-P..(2019).Non-PGM electrocatalysts for PEM fuel cells: Effect of fluorination on the activity and stability of a highly active NC-Ar + NH3 catalyst.Energy and Environmental Science,12(10).
MLA	Zhang G.,et al."Non-PGM electrocatalysts for PEM fuel cells: Effect of fluorination on the activity and stability of a highly active NC-Ar + NH3 catalyst".Energy and Environmental Science 12.10(2019).