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

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• 作者：Hsin-Yi Wang ; Sung-Fu Hung ; Han-Yi Chen ; Ting-Shan Chan ; Hao Ming Chen ; Bin Liu
• 刊名：Journal of the American Chemical Society
• 出版年：2016
• 出版时间：January 13, 2016
• 年：2016
• 卷：138
• 期：1
• 页码：36-39
• 全文大小：322K
• ISSN：1520-5126

文摘

Spinel Co₃O₄, comprising two types of cobalt ions: one Co²⁺ in the tetrahedral site (Co²⁺_Td) and the other two Co³⁺ in the octahedral site (Co³⁺_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 Co²⁺_Td and Co³⁺_Oh with inactive Zn²⁺ and Al³⁺, respectively. Following a thorough in operando analysis by electrochemical impedance spectroscopy and X-ray absorption spectroscopy, it was revealed that Co²⁺_Td site is responsible for the formation of cobalt oxyhydroxide (CoOOH), which acted as the active site for water oxidation.