In situ revealing the reconstruction behavior of monolayer rocksalt CoO nanosheet as water oxidation catalyst  

作　　者：Weiqi Guo Haolin Luo Dongxu Fang Zhi Jiang Jiasheng Chi Wenfeng Shangguan 

机构地区：[1]Research Center for Combustion and Environment Technology,Shanghai Jiao Tong University,Shanghai 200240,China [2]Center of Hydrogen Science,Shanghai Jiao Tong University,Shanghai 200240,China

出　　处：《Journal of Energy Chemistry》2022年第7期373-381,I0010,共10页能源化学（英文版）

基　　金：supported by the National Natural Science Foundation of China(21872093);the National Key Research and Development Program of China(2018YFB1502001);funding support from the Center of Hydrogen Science,Shanghai Jiao Tong University,China。

摘　　要：The reconstruction during oxygen evolution reaction (OER) significantly affects the electronic and local geometry structure of metal sites in electrocatalyst.Compared with well-investigated cobalt-based materials,the reconstruction of rocksalt CoO with purely Co^(2+) in octahedral (Oh) coordination has not been revealed in detail.Herein,monolayer Co O supported on reduced graphene oxide (r GO) was synthesized via a one-pot hydrothermal strategy with calcinating in Ar atmosphere.The structure evolution of twodimension (2D) Co O/r GO during OER was revealed by in situ X-ray absorption spectroscopy (XAS).The transition from Co O toward Co3O_(4) already occurred at open circuit potential,further enhanced at 1.23 V (vs.RHE).The Co Ox(OH)ywas determined as the active phase at 1.53 V,displaying a tetrahedral Co coordination defective spinel Co_(3)O_(4) with the Co-O shell that featured the (oxy)hydroxide,not the standard Co OOH.After OER,the irreversible transition from CoO to Co_(3)O_(4) was observed.In contrast,in situ Raman spectra revealed a reversible amorphization process on Co_(3)O_(4)/r GO under operation conditions.Furthermore,this study indicated that the reconstruction behavior could be more effectively revealed by XAS using 2D materials.

关 键 词：Oxygen evolution reaction Two-dimension materials Rocksalt CoO X-ray absorption spectroscopy In situ experiments 

分 类 号：O643.36[理学—物理化学] TB383.1[理学—化学]