Engineering Cationic Vacancies in Octahedral Sites of Co<sub>3</sub>O<sub>4</sub> for High-Efficiency Oxygen Evolution
Guangyi Chen, Shao-Li Zhu, Xiao-Qiang Han, Decheng Wang, Jiancheng Zhang, Xiang-Dong Huai, Xiang Li, Feiyue Zhang, Zhe Xiang, Wenzhuo Zhang
Abstract
The octahedral sites in Co 3 O 4 usually possess better oxygen evolution reaction (OER) activity, which have been identified as the active sites. Atomic cationic vacancy defects can elicit localized electron redistribution to regulate the electronic structure of the host materials. In this paper, Co 3 O 4 nanosheet arrays with cationic vacancies at octahedral sites (V x -Co 3 O 4 ) have been synthesized by a facile three-step reaction process. Density functional theory (DFT) computational results further indicate that the cationic vacancies can increase the number of electrons per Co atom and optimize the adsorption energy of the intermediate product. As a result, the optimized V 0.3 -Co 3 O 4 /CC electrode with abundant cationic vacancies displays excellent OER performance in alkaline electrolytes with an overpotential of 240 mV at 10 mA cm –2, Tafel slope of 72.2 mV dec –1, and superior stability, which are much better than those of the pure Co 3 O 4 and commercial IrO 2 .