J. Mater. Sci. Technol. ›› 2024, Vol. 203: 108-117.DOI: 10.1016/j.jmst.2024.03.038

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Self-healing of active site in Co(OH)2/MXene electrocatalysts for hydrazine oxidation

Kun Xianga,1, Yongjing Wanga,1, Zechao Zhuangb, Jing Zoua, Neng Lic, Dingsheng Wangb, Tianyou Zhaid, Jizhou Jianga,*   

  1. aSchool of Environmental Ecology and Biological Engineering, School of Chemistry and Environmental Engineering, Key Laboratory of Green Chemical Engineering Process of Ministry of Education, Engineering Research Center of Phosphorus Resources Development and Utilization of Ministry of Education, Novel Catalytic Materials of Hubei Engineering Research Center, Wuhan Institute of Technology, Wuhan 430205, China;
    bDepartment of Chemistry, Tsinghua University, Beijing 100084, China;
    cState Key Laboratory of Silicate Materials for Architectures, Wuhan University of Technology, Wuhan 430070, China;
    dState Key Laboratory of Material Processing and Die & Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
  • Received:2024-01-11 Revised:2024-03-04 Accepted:2024-03-31 Published:2024-12-20 Online:2024-12-16
  • Contact: *E-mail address: 027wit@163.com (J. Jiang) .
  • About author:1These authors contributed equally to this work.

Abstract: The development of efficient hydrazine oxidation reaction (HzOR) catalysts is important for the construction of remarkable energy storage and conversion systems. However, after a period of electrochemical reaction, the active site of the catalyst will be irreversibly reduced or inactivated, and how to recover the active site is a major challenge. Here, we report 2D Co(OH)2/Ti3C2(OH)x MXene composites with rapid reconstruction and self-healing behaviors as efficient and stable electrocatalysts during HzOR process. Both experimental and theoretical results indicate that the introduction of Ti3C2(OH)x MXene can effectively reduce the dehydrogenation barrier of Co(OH)2, from 0.584 eV to 0.481 eV to form the real catalytic active center Co(OH)O. Subsequently, Co(OH)O/Ti3C2(OH)x MXene composites with metal-like conductivity not only present spontaneous adsorption capacity of N2H4, but also can modulated rate-determining step of dehydrogenation of *N2H4 to *N2H3 (0.54 eV) compared with Co(OH)O. Finally, the electrophilic oxygen of Co(OH)O/Ti3C2(OH)x can spontaneously obtain electrons and protons from N2H4, achieving the oxidation of N2H4 while reducing Co(OH)O to Co(OH)2, thus completing the self-healing of the efficient catalyst.

Key words: Hydrazine oxidation, Self-healing, Reconstruction, Co(OH)2/MXene, Electrocatalysis