Stability of Fe‐N‐C Catalysts in Acidic Medium Studied by Operando Spectroscopy. Issue 43 (28th August 2015)

• Record Type: Journal Article
• Authors: Choi, Chang Hyuck; Baldizzone, Claudio; Grote, Jan‐Philipp; Schuppert, Anna K.; Jaouen, Frédéric; Mayrhofer, Karl J. J.
• Is Part Of: Angewandte Chemie international edition. Volume 54:Issue 43(2015)
• Page Start: 12753
• Page End: 12757
• Publication Date: 2015-08-28
• Subjects: Chemistry -- Periodicals; 540
• DOI: 10.1002/anie.201504903
• Languages: English
• ISSNs: 1433-7851

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <p>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 (&lt;0.7 V) without a direct adverse effect on the ORR activity, while carbon oxidation occurs at high potential (&gt;0.9 V) with a destruction of active sites such as FeN_{<italic>x</italic>}C_{<italic>y</italic>} 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.</p> </abstract>