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Carbon Corrosion in Proton‐Exchange Membrane Fuel Cells: Spectrometric Evidence for Pt‐Catalysed Decarboxylation at Anode‐Relevant Potentials
Author(s) -
Maillard Frédéric,
O. Silva Wanderson,
Castanheira Luis,
Dubau Laetitia,
Lima Fabio H. B.
Publication year - 2019
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.201900505
Subject(s) - anode , decarboxylation , proton exchange membrane fuel cell , chemistry , corrosion , catalysis , carbon fibers , fuel cells , inorganic chemistry , electrochemistry , membrane , proton , chemical engineering , materials science , organic chemistry , electrode , composite number , engineering , composite material , biochemistry , physics , quantum mechanics
The carbon oxidation reaction (COR) is a critical issue in proton‐exchange membrane fuel cells (PEMFCs), as carbon in various forms is the most used electrocatalyst support material. The COR is thermodynamically possible above the C/CO 2 standard potential, but its rate becomes significantly important only at high overpotential (e. g. PEMFC cathode potential). Herein, using on‐line differential electrochemical mass spectrometry, we show that oxygen‐containing carbon surface groups present on high‐surface aera carbon, Vulcan XC72 or reinforced graphite are oxidized at PEMFC anode‐relevant potential ( E =0.1 V vs. the reversible hydrogen electrode, RHE), but not at E =0.4 V vs. RHE. We rationalized our findings by considering a Pt‐catalysed decarboxylation mechanism in which Pt nanoparticles provide adsorbed hydrogen species to the oxygen‐containing carbon surface groups, eventually leading to evolution of carbon dioxide and carbon monoxide. These results shed fundamental light on an unexpected degradation mechanism and facilitate the understanding of the long‐term stability of PEMFC anode nanocatalysts.