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The Structure of the Cobalt Oxide/Au Catalyst Interface in Electrochemical Water Splitting
Author(s) -
Fester Jakob,
Makoveev Anton,
Grumelli Doris,
Gutzler Rico,
Sun Zhaozong,
RodríguezFernández Jonathan,
Kern Klaus,
Lauritsen Jeppe V.
Publication year - 2018
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201804417
Subject(s) - cobalt , cobalt oxide , x ray photoelectron spectroscopy , electrocatalyst , catalysis , oxide , monolayer , cyclic voltammetry , oxygen evolution , electrochemistry , scanning tunneling microscope , water splitting , materials science , inorganic chemistry , chemical engineering , chemistry , nanotechnology , electrode , photocatalysis , metallurgy , biochemistry , engineering
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.