Urea oxidation reaction (UOR) is emerging as a thermodynamically favorable alternative to the oxygen evolution reaction, offering significant potential for energy-efficient H2 production and simultaneous treatment of urea-rich wastewater. However, the 6 e− transfer process of UOR results in sluggish kinetics, necessitating the development of highly efficient electrocatalysts. Herein, a Janus charge distribution surface is constructed by incorporating phosphorus (P) into the Ni3S2/Co9S8 heterojunction to enhance UOR performance and accelerate urea-assisted H2 production. The P incorporation facilitates electron transfer from Ni3S2 to Co9S8, creating a local electrophilic/nucleophilic interface that enhances the adsorption of urea molecules with electron-withdrawing C=O group and electro-donating amino groups. As a result, the modified P-Ni3S2/Co9S8 exhibits ultralow potentials of 1.22, 1.30 and 1.39 V (versus reversible hydrogen electrode) to reach 10, 100 and 1000 mA cm−2 for UOR, respectively. Remarkably, when alkaline urine is used as the electrolyte, the P-Ni3S2/Co9S8 catalyst, functioning as a bifunctional electrocatalyst in an anion-exchange membrane electrolyzer, can stably deliver a high current density of 1000 mA cm−2 for H2 production over 180 h. This work highlights the importance of designing electrocatalysts by activating interfacial charge distribution to enhance reactants adsorption and trigger chemical bonds cleavage.
