Co-vacancy-rich CO1-xS nanosheets anchored on rGO for high-efficiency oxygen evolution

作     者：Jiaqing Zhu Zhiyu Ren Shichao Du Ying Xie Jun Wu Huiyuan Meng Yuzhu Xue Honggang Fu 

作者机构：Key Laboratory of Functional Inorganic Material Chemistry Ministry of Education of the People's Republic of China School of Chemistry College of Materials Science and Chemical Engineering Harbin Engineering University Harbin 150001 China 

出 版 物：《Nano Research》 (纳米研究（英文版）)

年 卷 期：2017年第10卷第5期

页      面：1819-1831页

核心收录：

学科分类：07[理学] 

基　　金：support of this research by the National Natural Science Foundation of China the Project for Foshan Innovation Group Application Technology Research and Development Projects in Harbin the International Science & Technology Cooperation Program of China the Foundation of Heilongjiang Province of China the supporting plan for Excellent Youth of Heilongjiang University 

主　　题：cobalt vacancies (Vco) Co1-xS oxygen evolution reaction electrocatalysis nanosheets 

摘      要：Developing cost-efficient electrocatalysts for oxygen evolution is vital for the viability of H2 energy generated via electrolytic water. Engineering favorable defects on the electrocatalysts to provide accessible active sites can boost the sluggish reaction thermodynamics or kinetics. Herein, Col_xS nanosheets were designed and grown on reduced graphene oxide （rGO） by controlling the successive two-step hydrothermal reaction. A belt-like cobalt-based precursor was first formed with the assistance of ammonia and rGO, which were then sulfurized into Col_xS by L-cysteine at a higher hydrothermal temperature. Because of the non-stoichiometric defects and ultrathin sheet-like structure, additional cobalt vacancies （V^o） were formed/exposed on the catalyst surface, which expedited the charge diffusion and increased the electroactive surface in contact with the electrolyte. The resulting Col_xS/rGO hybrids exhibited an overpotential as low as 310 mV at 10 ***-2 in an alkaline electrolyte for the oxygen evolution reaction （OER）. Density functional theory calculations indicated that the Vco on the Col_xS/rGO hybrid functioned as catalytic sites for enhanced OER. They also reduced the energy barrier for the transformation of intermediate oxygenated species, promoting the OER thermodynamics.