J. Mater. Sci. Technol. ›› 2025, Vol. 228: 279-286.DOI: 10.1016/j.jmst.2025.01.005

• Research article • Previous Articles     Next Articles

Nitrogen vacancies cobalt nitride and its loading Pt electrocatalysts for efficient overall water splitting

Yujie Luana,1, Xiaolin Yana,b,c,1, Chengwei Jia, Changpeng Lvb,*, Di Land, Siyuan Zhange, Jin Suna,*, Daohao Lia,f,*, Guanglei Wuf,*   

  1. aState Key Laboratory of Bio-fibers and Eco-textiles, School of Environment and Geography, Qingdao University, Qingdao 266071, China;
    bAnhui Provincial Engineering Research Center of Silicon-Based Materials, School of Material and Chemical Engineering, Bengbu University, Bengbu 233030, China;
    cCollege of Physics, Qingdao University, Qingdao 266071, China;
    dSchool of Automotive Materials, Hubei University of Automotive Technology, Shiyan 442002, China;
    eSchool of Chemistry and Chemical Engineering, Northwestern Polytechnical University, Xi'an 710072, China;
    fCollege of Materials Science and Engineering, Qingdao University, Qingdao 266071, China
  • Received:2024-12-10 Revised:2025-01-17 Accepted:2025-01-17 Published:2025-09-01 Online:2025-09-01
  • Contact: *E-mail addresses: lcp@bbc.edu.cn (C. Lv), sunjin@qdu.edu.cn (J. Sun), lidaohao@qdu.edu.cn (D. Li), wuguanglei@qdu.edu.cn , wuguanglei@mail.xjtu.edu.cn (G. Wu)
  • About author:1These authors contributed equally to this work.

Abstract: Anion exchange membrane electrolysis (AEMWE) is currently a promising technology to produce hydrogen from water. Developing the highly intrinsic activity of electrodes is extremely important. In this paper, nitrogen vacancies-rich cobalt nitride (Co4N-VN) is used as the anode catalyst of the urea oxidation reaction (UOR) and its loading Pt (Pt@Co4N-VN) acted as the cathode of hydrogen evolution reaction (HER). The introduction of N-vacancies gained the electron-deficient Co4N more favorable for the UOR process. Meanwhile, the electron transfer between the Co4N-VN carrier and Pt can enhance the intrinsic HER activity of loaded Pt. Specifically, in the 0.33 M urea and 1.0 M KOH electrolyte, the UOR potential of CO4N-VN is only 1.58 V at the current density of 300.0 mA cm-2, which is much lower than that of Co4 N and Co3O4. At the same time, the HER overpotential at 1.0 M KOH and 300.0 mA cm-2 is only 120.0 mV, lower than 20 wt% Pt/C. By measuring the bode phase diagram, the presence of N-vacancies can accelerate the electron transfer rate of catalysts to improve the UOR and HER electrocatalytic activity. The overall water-splitting device featuring Pt@Co4N-VN||Co4N-VN electrodes achieves a voltage of 2.99 V at a current density of 300.0 mA cm-2.

Key words: Cobalt nitride, Vacancy, Urea oxidation reaction, Hydrogen evolution reaction, Overall water splitting