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The development of efficient urea oxidation reaction (UOR) catalysts helps UOR replace the oxygen evolution reaction (OER) in hydrogen production from water electrolysis. Here, we prepared Fe-doped Ni 2 P/NiSe 2 composite catalyst (Fe-Ni 2 P/NiSe 2 -12) by using phosphating-selenizating and acid etching to increase the intrinsic activity and active areas. Spectral characterization and theoretical calculations demonstrated that electrons flowed through the Ni-P-Fe-interface-Ni-Se-Fe, thus conferring high UOR activity to Fe-Ni 2 P/NiSe 2 -12, which only needed 1.39 V vs RHE to produce the current density of 100 mA cm -2 . Remarkably, this potential was 164 mV lower than that required for the OER under the same conditions. Furthermore, EIS demonstrated that UOR driven by the Fe-Ni 2 P/NiSe 2 -12 exhibited faster interfacial reactions, charge transfer, and current response compared to OER. Consequently, the Fe-Ni 2 P/NiSe 2 -12 catalyst can effectively prevent competition with OER and NSOR, making it suitable for efficient hydrogen production in UOR-assisted water electrolysis. Notably, when water electrolysis is operated at a current density of 40 mA cm -2 , this UOR-assisted system can achieve a decrease of 140 mV in the potential compared to traditional water electrolysis. This study presents a novel strategy for UOR-assisted water splitting for energy-saving hydrogen production.

A long-term goal of rechargeable zinc-air batteries (ZABs) has always been to design bifunctional electrocatalysts that are robust, effective, and affordable for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). It has become a feasible method to construct metal/metal oxide interfaces to achieve superior electrocatalytic performance for ORR and OER by enhanced charge transfer. In this study, Co/Co 3 O 4 heterojunctions were successfully prepared and encased in porous N-doped mesoporous carbon (Co/Co 3 O 4 @NC) via a simple condensation-carbonization-etching method. The extensive specific surface area of Co/Co 3 O 4 @NC facilitates effective interaction between the electrolyte and the catalyst, thereby enabling sufficient exposure of active sites for the ORR and the OER, consequently enhancing the rate of transport of active species. The well-designed Co/Co 3 O 4 @NC delivers superior ORR catalytic activity with a half-wave potential of 0.82 V (vs RHE) and a low overpotential of 347 mV at 10 mA cm -2 for OER in alkaline solution. The power density of Co/Co 3 O 4 @NC-based alkaline aqueous ZAB (156.5 mW cm -2 ) is superior to the commercial Pt/C + IrO 2 -based alkaline aqueous ZAB, and the cycling stability of ZAB is up to 220 h. In addition, Co/Co 3 O 4 @NC-based ZAB shows a high power density (50.1 mW cm -2 ). The construction of metal/metal oxide heterojunction encased in N-doped mesoporous carbon provides a novel route for the design of bifunctional electrocatalysts for high-performance ZABs.