In Operando Identification of Geometrical-Site-Dependent Water Oxidation Activity of Spinel Co3O4.

By Hsin‐Yi Wang, Sung-Fu Hung, Hanbin Chen, T. Chan, Hao Ming Chen, Bin Liu. Journal of the American Chemical Society, 2016

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Spinel Co3O4, comprising two types of cobalt ions: one Co(2+) in the tetrahedral site (Co(2+)(Td)) and the other two Co(3+) in the octahedral site (Co(3+)(Oh)), has been widely explored as a promising oxygen evolution reaction (OER) catalyst for water electrolysis. However, the roles of two geometrical cobalt ions toward the OER have remained elusive. Here, we investigated the geometrical-site-dependent OER activity of Co3O4 catalyst by substituting Co(2+)(Td) and Co(3+)(Oh) with inactive Zn(2+) and Al(3+), respectively. Following a thorough in operando analysis by electrochemical impedance spectroscopy and X-ray absorption spectroscopy, it was revealed that Co(2+)Td site is responsible for the formation of cobalt oxyhydroxide (CoOOH), which acted as the active site for water oxidation.

Subfields: Electrical and Electronic Engineering, Electrochemistry, Renewable Energy, Sustainability and the Environment

View Paper: https://www.semanticscholar.org/paper/36e85179372ca0ba59cbea9815c0ba89bd33781c