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Stability of Fe‐N‐C Catalysts in Acidic Medium Studied by Operando Spectroscopy
Author(s) -
Choi Chang Hyuck,
Baldizzone Claudio,
Grote JanPhilipp,
Schuppert Anna K.,
Jaouen Frédéric,
Mayrhofer Karl J. J.
Publication year - 2015
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201504903
Subject(s) - catalysis , chemistry , electrochemistry , electrolyte , leaching (pedology) , rotating disk electrode , mass spectrometry , degradation (telecommunications) , inductively coupled plasma mass spectrometry , spectroscopy , chemical engineering , metal , inorganic chemistry , analytical chemistry (journal) , electrode , cyclic voltammetry , environmental chemistry , chromatography , organic chemistry , telecommunications , physics , environmental science , quantum mechanics , computer science , soil science , engineering , soil water
Fundamental understanding of non‐precious metal catalysts for the oxygen reduction reaction (ORR) is the nub for the successful replacement of noble Pt in fuel cells and, therefore, of central importance for a technological breakthrough. Herein, the degradation mechanisms of a model high‐performance Fe‐N‐C catalyst have been studied with online inductively coupled plasma mass spectrometry (ICP‐MS) and differential electrochemical mass spectroscopy (DEMS) coupled to a modified scanning flow cell (SFC) system. We demonstrate that Fe leaching from iron particles occurs at low potential (<0.7 V) without a direct adverse effect on the ORR activity, while carbon oxidation occurs at high potential (>0.9 V) with a destruction of active sites such as FeN x C y species. Operando techniques combined with identical location‐scanning transmission electron spectroscopy (IL‐STEM) identify that the latter mechanism leads to a major ORR activity decay, depending on the upper potential limit and electrolyte temperature. Stable operando potential windows and operational strategies are suggested for avoiding degradation of Fe‐N‐C catalysts in acidic medium.