J. Mater. Sci. Technol. ›› 2023, Vol. 154: 1-8.DOI: 10.1016/j.jmst.2022.12.042

• Research Article •     Next Articles

Engineering Cu1.96S/Co9S8 with sulfur vacancy and heterostructure as an efficient bifunctional electrocatalyst for water splitting

Yuanhua Xiaoa,*, Ya Shena, Dangcheng Sua, Shiwei Zhanga, Jinlin Yangb, Dafeng Yanc,*, Shaoming Fanga, Xuezhao Wangd,*   

  1. aKey Laboratory of Surface & Interface Science and Technology/College of Material and Chemical Engineering, Zhengzhou University of Light Industry, Zhengzhou 450002, China;
    bDepartment of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore;
    cCollege of Chemistry and Chemical Engineering, Hubei University, Wuhan 430062, China;
    dCollege of Chemical and Food, Zhengzhou University of Technology, Zhengzhou 450044, China
  • Received:2022-09-06 Revised:2022-12-12 Accepted:2022-12-19 Published:2023-08-10 Online:2023-02-26
  • Contact: *E-mail addresses: yuanhua_xiao@163.com (Y. Xiao), dafengyan@hnu.edu.cn (D. Yan), xzhwang126@126.com (X. Wang)

Abstract: Defect and interface engineering have been recognized as efficient strategies for developing high-performance electrocatalysts. However, it is still challenging to couple defect and interface engineering in transition metal sulfides and understand their dynamic evolution process during electrocatalysis. Herein, we developed one-step pyrolysis of bimetallic sulfide to construct S vacancy-rich Cu1.96S/Co9S8 heterostructure by controlling the critical decomposition temperature. The as-synthesized Cu1.96S/Co9S8 exhibits excellent bifunctional electrocatalytic performance, with a low overpotential of 99 and 200 mV at 10 mA cm-2 towards hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in 1.0 mol/L KOH electrolyte, respectively. A symmetric two-electrode cell with Cu1.96S/Co9S8 delivered a current density of 10 mA cm-2 at a low voltage of 1.43 V and showed long-term stability for 200 h. A series of in/ex-situ techniques revealed that the electrochemical reconfiguration only appeared in the OER process, resulting in the CoOOH/CuO and SO42- species promoting OER performance. Meanwhile, the S vacancy and heterostructure interface in Cu1.96S/Co9S8 were proved to optimize the electronic structure and the adsorption of intermediates for HER by density function theory (DFT) simulations. This work provides a promising strategy to construct metal sulfides with rich defects and heterogeneous interfaces and understand their dynamic evolution process for electrochemical storage and conversion devices.

Key words: Cu1.96S/Co9S8, S vacancy, Heterostructure, Overall water-splitting