The Structure of the Cobalt Oxide/Au Catalyst Interface in Electrochemical Water Splitting

Jakob Fester, Anton Makoveev, Doris Grumelli, Rico Gutzler, Zhaozong Sun, Jonathan Rodríguez-Fernández, Klaus Kern, Jeppe V. Lauritsen*

*Corresponding author for this work

Research output: Contribution to journal/Conference contribution in journal/Contribution to newspaperJournal articleResearchpeer-review

Abstract

The catalytic synergy between cobalt oxide and gold leads to strong promotion of the oxygen evolution reaction (OER)—one half-reaction of electrochemical water splitting. However, the mechanism behind the enhancement effect is still not understood, in part due to a missing structural model of the active interface. Using a novel interplay of cyclic voltammetry (CV) for electrochemistry integrated with scanning tunneling microscopy (STM) and X-ray photoelectron spectroscopy (XPS) on an atomically defined cobalt oxide/Au(111) system, we reveal here that the supporting gold substrate uniquely favors a flexible cobalt-oxyhydroxide/Au interface in the electrochemically active potential window and thus suppresses the formation of less active bulk cobalt oxide morphologies. The findings substantiate why optimum catalytic synergy is obtained for oxide coverages on gold close to or below one monolayer, and provide the first morphological description of the active phase during electrocatalysis.

Original languageEnglish
JournalAngewandte Chemie - International Edition
Volume57
Issue37
Pages (from-to)11893-11897
Number of pages5
ISSN1433-7851
DOIs
Publication statusPublished - 10 Sept 2018

Keywords

  • electrocatalysis
  • metal oxides
  • oxygen evolution reactions
  • scanning tunneling microscopy

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