Constructing an adaptive heterojunction as a highly active catalyst for the oxygen evolution reaction

• Main Authors: Ren, Xiao, Wei, Chao, Sun, Yuanmiao, Liu, Xiaozhi, Meng, Fanqi, Meng, Xiaoxia, Sun, Shengnan, Xi, Shibo, Du, Yonghua, Bi, Zhuanfang, Shang, Guangyi, Fisher, Adrian C., Gu, Lin, Xu, Jason Zhichuan
• Other Authors: School of Materials Science and Engineering
• Format: Article
• Language: English
• Published: 2022
• Subjects: Engineering::Materials; Adaptive Junctions; Cycling
• Online Access: https://hdl.handle.net/10356/161097
• Institution: Nanyang Technological University

Electrochemical water splitting is of prime importance to green energy technology. Particularly, the reaction at the anode side, namely the oxygen evolution reaction (OER), requires a high overpotential associated with OO bond formation, which dominates the energy-efficiency of the whole process. Activating the anionic redox chemistry of oxygen in metal oxides, which involves the formation of superoxo/peroxo-like (O2 )n - , commonly occurs in most highly active catalysts during the OER process. In this study, a highly active catalyst is designed: electrochemically delithiated LiNiO2 , which facilitates the formation of superoxo/peroxo-like (O2 )n - species, i.e., NiOO*, for enhancing OER activity. The OER-induced surface reconstruction builds an adaptive heterojunction, where NiOOH grows on delithiated LiNiO2 (delithiated-LiNiO2 /NiOOH). At this junction, the lithium vacancies within the delithiated LiNiO2 optimize the electronic structure of the surface NiOOH to form stable NiOO* species, which enables better OER activity. This finding provides new insight for designing highly active catalysts with stable superoxo-like/peroxo-like (O2 )n - for water oxidation.