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Experimental and Computational Evidence of Highly Active Fe Impurity Sites on the Surface of Oxidized Au for the Electrocatalytic Oxidation of Water in Basic Media
Author(s) -
Klaus Shan,
Trotochaud Lena,
Cheng MuJeng,
HeadGordon Martin,
Bell Alexis T.
Publication year - 2016
Publication title -
chemelectrochem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.182
H-Index - 59
ISSN - 2196-0216
DOI - 10.1002/celc.201500364
Subject(s) - overpotential , oxygen evolution , chemistry , electrochemistry , oxygen , density functional theory , impurity , energetics , water splitting , inorganic chemistry , redox , catalysis , computational chemistry , electrode , thermodynamics , organic chemistry , physics , photocatalysis
Abstract Addition of Fe to Ni‐ and Co‐based (oxy)hydroxides has been shown to enhance the activity of these materials for electrochemical oxygen evolution. Here we show that Fe cations bound to the surface of oxidized Au exhibit enhanced oxygen evolution reaction (OER) activity. We find that the OER activity increases with increasing surface concentration of Fe. Density functional theory analysis of the OER energetics reveals that oxygen evolution over Fe cations bound to a hydroxyl‐terminated oxidized Au (Fe–Au 2 O 3 ) occurs at an overpotential ∼0.3 V lower than over hydroxylated Au 2 O 3 (0.82 V). This finding agrees well with experimental observations and is a consequence of the more optimal binding energetics of OER reaction intermediates at Fe cations bound to the surface of Au 2 O 3 . These findings suggest that the enhanced OER activity reported recently upon low‐potential cycling of Au may be due to surface Fe impurities rather than to “superactive” Au III surfaquo species.