Cu, Co co-doped Ni3S2 nanosheets grown on nickel foam as an efficient catalyst for urea oxidation reaction

Doping modification can significantly enhance the catalytic performance of Ni3S2 in urea oxidation reaction (UOR). In this study, we synthesized Cu, Co co-doped Ni3S2 nanosheets on nickel foam (Cu/Co-Ni3S2/NF) through a two-step hydrothermal reaction. Cu, Co dual-doped Ni3S2 nanosheets exhibited a thickness of about 30 nm, composed of nanoparticles. Benefiting from the synergistic regulation of Cu and Co dopants on electronic structure, increased availability of active sites, boosted electron transference rates, and improved electrical conductivity, Cu/Co-Ni3S2/NF exhibited an excellent UOR catalytic performance and enhanced reaction kinetics, offering a low potential of 1.350 V at 100 mA cm-2, along with a low Tafel slope of 15.5 mV dec-1. Moreover, Cu/Co-Ni3S2/NF coupled with Pt/C/NF only necessitated 1.68 V to drive 100 mA cm-2 for overall urea splitting, which is lower than that of traditional water splitting (1.996 V). This indicates that the addition of urea into electrolyte is an energy-conserving strategy for hydrogen production from water electrolysis. This work provides a novel dual-ion doping method to design a highly efficient electrocatalysts for UOR.