Activating Janus charge distribution on the P-doped NiS/CoS interface for enhancing charge-matched urea adsorption: boosting high current hydrogen production coupled urine degradation.

The urea oxidation reaction (UOR) is emerging as a thermodynamically favorable alternative to the oxygen evolution reaction, offering significant potential for energy-efficient H production and simultaneous treatment of urea-rich wastewater. However, the 6 e transfer process of the 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 NiS/CoS heterojunction to enhance the UOR performance and accelerate urea-assisted H production. The P incorporation facilitates electron transfer from NiS to CoS, creating a local electrophilic/nucleophilic interface that enhances the adsorption of urea molecules with the electron-withdrawing C[double bond, length as m-dash]O group and electron-donating amino groups. As a result, the modified P-NiS/CoS exhibits ultralow potentials of 1.22, 1.30 and 1.39 V ( the reversible hydrogen electrode) to reach 10, 100 and 1000 mA cm for the UOR, respectively. Remarkably, when alkaline urine is used as the electrolyte, the P-NiS/CoS catalyst, functioning as a bifunctional electrocatalyst in an anion-exchange membrane electrolyzer, can stably deliver a high current density of 1000 mA cm for H production over 180 h. This work highlights the importance of designing electrocatalysts by activating interfacial charge distribution to enhance reactant adsorption and trigger chemical bond cleavage.