A CuMo dual-doped Ni3S2 porous ultrathin nanosheet as an efficient bifunctional electrocatalyst for urea–water electrolysis

The development of efficient and energy-saving electrocatalysts for urea-assisted hydrogen production has attracted considerable attention in sustainable energy technologies. In this work, a three-dimensional porous CuMo dual-doped Ni₃S₂ ultrathin nanosheet (CuMo–Ni₃S₂) catalyst was successfully synthesized via a one-step hydrothermal method on Ni foam. The synergistic doping of Cu and Mo elements induced a remarkable morphology transformation of Ni₃S₂ from nanofold structures to porous ultrathin nanosheets, significantly enhancing the electrochemical active surface area and exposing abundant active sites. The resulting catalyst exhibited excellent activity and durability for both the urea oxidation reaction (UOR) and the hydrogen evolution reaction (HER). Specifically, the catalyst required only 1.40 V (vs. RHE) to achieve a current density of 10 mA cm⁻² for the UOR, and a low overpotential of 115 mV for the HER at the same current density. Notably, the catalyst maintained stable performance after 50 h of continuous operation with no significant activity decay. Furthermore, the overall urea electrolyzer constructed with CuMo–Ni₃S₂ as both UOR and HER catalysts only required a cell voltage of 1.55 V to deliver a current density of 10 mA cm⁻². This study provides an effective approach for developing low-cost, high-performance electrocatalysts for sustainable hydrogen production through urea electrolysis.