Regulating Reaction Intermediate Adsorption of Co_0.5NiS₂–Ni₃S₂ Nanorods for Efficient Urea Electrolysis

Urea-assisted water electrolysis integrated by a urea oxidation reaction (UOR) and a hydrogen evolution reaction (HER) is an efficient strategy for energy-saving hydrogen production. However, its practical application requires catalysts with sufficient durability and high-strength reactant/product diffusion capability under large current densities. Herein, the Co_0.5NiS₂–Ni₃S₂ coral-like nanorods (Co_0.5NiS₂–Ni₃S₂/NF) of electronic structure and morphology regulation are rationally constructed. The heterostructure and sulfur vacancies induce interfacial charge redistribution, thus promoting the adsorption of urea and *OH intermediates, accompanied by accelerating the dissociation of H₂O. Moreover, the hierarchical nanorod structure ensures mass transfer and gas product rapid escape. As a result, Co_0.5NiS₂–Ni₃S₂/NF only takes 1.45 V and −345 mV to reach large current densities of ±1500 mA cm^–2 for the UOR and HER, respectively. Notably, the overall urea electrolysis system needs only 2.00 V to obtain 1500 mA cm^–2, and it can operate stably for 120 h at 500 mA cm^–2. This work illustrates the importance of regulating the adsorption energy of intermediates to design advanced catalysts for energy-efficient H₂ production from urea electrolysis.