Boronization of ZIF-67 on nickel foam to prepare self-supporting NiCo-bimetallic borides electrocatalyst for efficient oxygen evolution reaction

The research and development of self-supporting transition metal catalysts are of great significance to the practical application of water splitting. Among these, transition metal boride exhibits high catalytic activity and exceptional stability. In this study, a large specific surface area structure (SSAS) of ZIF-67 nanorods grown on nickel foam (NF) was constructed, which reacted with boron carbide (B4C) to prepare a self-supporting NiCo-bimetallic boride loading on nitrogen-doped carbon nanorods (NixB-Co4B@NC/NF-800) for efficient oxygen evolution reaction (OER). The SSAS of NixB-Co4B@NC/NF-800 catalyst enhanced the exposure of active edge sites. Meanwhile, the connection between bimetallic boride and doped carbon could promote charge transfer. And the structure of nanorods modified with nanosheets contributed to the transmission and release of bubbles on the catalyst surface during electrolysis. The synergistic effect of bimetallic borides facilitated to reduce the reaction barrier and accelerate the OER reaction. The NixB-Co4B@NC/NF-800 required an overpotential of 247 and 296 mV to achieve 10 and 50 mA cm−2, respectively, which is on a par with IrO2/C. In addition, due to its unique structure (nanorods modified with nanosheets), the NixB-Co4B@NC/NF-800 also showed excellent electrochemical stability.