Metal–organic-framework embellished through ion etching method for highly enhanced electrochemical oxygen evolution reaction catalysis

Abstract

Metal–organic-frameworks (MOFs) are scarcely considered to catalyse electrochemical reactions directly due to the limitation of their bulk structure, poor conductivity, and scarce active sites. Fe ions, as effective activity boosters for nickel-based catalysts, can effectively modulate the neatly arranged structure and electron configuration of MOF materials through the penetrating and etching process. Therefore, a Fe ion etching method was employed to modulate the structure and electronic configuration of bulk MOF. The resulting Ni-MOF-Fe-2 was equipped with a wider pore width distribution and lower crystallinity, and the Fe ion doping induced many dislocations and stacking faults in the lattice planes, which provided sufficient defects and active sites for OER. Therefore, Ni-MOF-Fe-2 displayed an advanced performance with an overpotential of 269 mV at the current density of 10 mA cm⁻², and the small Tafel slope of 47.1 mV dec⁻¹ and charge transfer resistances (R_ct) of 8.31 Ω revealed its fast kinetics and high electron transfer efficiency, indicating that Fe ion etching played an important role in booting OER performance of Ni MOF.