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Oxygen vacancies engineered CoMoO4 nanosheet arrays as efficient bifunctional electrocatalysts for overall water splitting

Chi, Kai, Tian, Xin, Wang, Qijun, Zhang, Zheye, Zhang, Xiangyu, Zhang, Yan, Jing, Feng, Lv, Qiying, Yao, Wei, Xiao, Fei, Wang, Shuai
Journal of catalysis 2020 v.381 pp. 44-52
alkalinity, ammonia, catalysts, durability, electric potential difference, electrochemistry, electron transfer, energy conversion, foams, heat treatment, hydrogen, hydrogen production, nanosheets, nickel, oxygen, oxygen production, water
The development of highly efficient, stable and earth-abundant bifunctional electrocatalysts for water splitting is of great significance for confronting the environmental and energy crisis. In this work, we reported the design and synthesis of oxygen vacancies engineered CoMoO₄ nanosheet arrays grown on three-dimension (3D) porous Ni foam (NF) support by hydrothermal synthesis followed by reducing gas heat treatment used H₂ or NH₃, and explored their practical application as bifunctional electrocatalysts for water splitting. The unique 3D nanosheet array can facilitate the interfacial electron transfer and ion transport, as well as promote hydrogen and oxygen gas diffusion, and the formation of oxygen vacancies in CoMoO₄ nanosheets can significantly improve efficiency of both hydrogen evolution reaction and oxygen evolution reaction. When using as self-supported bifunctional electrocatalyst to make an electrolyzer, NF/H-CoMoO₄ approached 10 mA cm⁻² under the cell voltages of 1.56 V, along with excellent durability in an alkaline water electrolyzer, which hold great promise in energy conversion application.