Surface Proton Hopping and Fast-Kinetics Pathway of Water Oxidation on Co3O4 (001) Surface

Hieu H. Pham, Mu Jeng Cheng, Heinz Frei, Lin Wang Wang

研究成果: Article

33 引文 斯高帕斯(Scopus)

摘要

We propose a mechanism of water splitting on cobalt oxide surface with atomistic thermodynamic and kinetic details. The density-functional theory studies suggest that the oxidation process could proceed with several nonelectrochemical (spontaneous) intermediate steps, following the initial electrochemical hydroxyl-to-oxo conversion. More specifically, the single oxo sites CoIV=O can hop (via surface proton/electron hopping) to form oxo pair CoIV(=O)-O-CoIV=O, which will undergo nucleophilic attack by a water molecule and form the hydroperoxide CoIII-OOH. Encounter with another oxo would generate a superoxo CoIII-OO, followed by the O2 release. Finally the addition and deprotonation of a fresh water molecule will restart the catalytic cycle by forming the hydroxyl CoIII-OH at this active site. Our theoretical investigations indicate that all nonelectrochemical reactions are kinetically fast and thermodynamically downhill. This hypothesis is supported by recent in situ spectroscopic observations of surface superoxo that is stabilized by hydrogen bonding to adjacent hydroxyl group as an intermediate on fast-kinetics Co catalytic site.

原文English
頁(從 - 到)5610-5617
頁數8
期刊ACS Catalysis
6
發行號8
DOIs
出版狀態Published - 2016 八月 5

All Science Journal Classification (ASJC) codes

  • Catalysis
  • Chemistry(all)

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