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

• DOI: 10.1021/jacs.5b10525
• Publication Date: 2015-12-28T18:24:56Z
• Authors: Hsin-Yi Wang; Sung-Fu Hung; Han-Yi Chen; Ting-Shan Chan; Hao Ming Chen; Bin Liu
• Keywords: Oxygen evolution; X-ray absorption spectroscopy

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