Synergistic metal–nonmetal co-doping in Ni3S2 for enhanced bifunctional water–urea electrolysis

Abstract

The pursuit of affordable bifunctional electrocatalysts capable of effectively facilitating the oxygen evolution reaction (OER) and urea oxidation reaction (UOR) still faces significant hurdles. Herein, an Fe and B co-doped Ni₃S₂ catalyst was supported on nickel foam (Fe,B–Ni₃S₂/NF) in a single-step hydrothermal method. X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy confirmed the effective incorporation of Fe and B into the Ni₃S₂ lattice. The concerted effect of the metal and non-metal dopants regulated the electronic configuration of Ni₃S₂ to expose more active sites, enhancing electronic interactions and improving the charge transfer efficiency. The optimized catalyst exhibited remarkable catalytic activity, needing only 1.494 V for the OER to achieve 100 mA cm⁻² and a mere 1.326 V for the UOR to attain 10 mA cm⁻², and presented a superb 260 h of stability with negligible decay. This research offers a straightforward tactic for devising transition-metal sulfides for sustainable hybrid water–urea electrolysis systems.