Controllable Integration of Nickel Selenide with Porous Carbon Nanofibers for Efficient Electrocatalytic Urea Oxidation

Electrocatalytic urea oxidation reaction (UOR) represents a promising alternative to the oxygen evolution reaction for energy-saving hydrogen production owing to its lower thermodynamic equilibrium potential. To address the intrinsically sluggish six-electron transfer kinetics of UOR, the design and fabrication of highly efficient catalysts are essential. Here, a facile electrospinning-based strategy is developed to achieve the controllable integration of Ni0.85Se with Ni-based porous carbon nanofibers (Ni-PCNFs/NiSe). Experimental evidence further reveals that the surface Ni0.85Se nanoparticles undergo reconstruction into high-valent NiOOH during the electrocatalytic process, while the remaining Ni0.85Se embedded in the PCNFs ensures structural stability, collectively enhancing the UOR activity. Owing to its rational compositional and structural design, the optimized Ni-PCNFs0.2/NiSe-2 catalyst exhibits remarkable UOR performance, achieving a low potential of 1.37 V versus reversible hydrogen electrode (vs RHE) at a current density of 20 mA·cm–2. Moreover, when configured as the anode in a urea-assisted water splitting (OUS) electrolyzer, the Ni-PCNFs0.2/NiSe-2 catalyst enables the system to achieve a current density of 10 mA·cm–2 at a low voltage of 1.39 V. This work presents new horizons for the design and fabrication of advanced UOR catalysts for efficient OUS.