Photoelectron spectroscopy at the graphene-liquid interface reveals the electronic structure of an electrodeposited cobalt/graphene electrocatalyst

Velasco-Vélez, JJ; Pfeifer, V; Hävecker, M; Weatherup, RS; Arrigo, R; Chuang, C-H; Stotz, E; Weinberg, G; Salmeron, M; Schlögl, R; Knop-Gericke, A

Abstract

Electrochemically grown cobalt on graphene exhibits exceptional performance as a catalyst for the oxygen evolution reaction (OER) and provides the possibility of controlling the morphology and the chemical properties during deposition. However, the detailed atomic structure of this hybrid material is not well understood. To elucidate the Co/graphene electronic structure, we have developed a flow cell closed by a graphene membrane that provides electronic and chemical information on the active surfaces under atmospheric pressure and in the presence of liquids by means of X‐ray photoelectron spectroscopy (XPS). We found that cobalt is anchored on graphene via carbonyl‐like species, namely Co(CO)x, promoting the reduction of Co3+ to Co2+, which is believed to be the active site of the catalyst.

• Journal Article Type: Article
• Acceptance Date: Jul 17, 2015
• Online Publication Date: Oct 14, 2015
• Publication Date: Nov 23, 2018
• Deposit Date: Dec 4, 2018
• Journal: Angewandte Chemie International Edition
• Print ISSN: 1433-7851
• Electronic ISSN: 1521-3773
• Publisher: Wiley
• Volume: 54
• Issue: 48
• Pages: 14554-14558
• DOI: https://doi.org/10.1002/anie.201506044
• Publisher URL: https://doi.org/10.1002/anie.201506044
• Related Public URLs: https://onlinelibrary.wiley.com/journal/15213773