Direct urea oxidation pathway enabled by Mo-regulated Ni2P-MoOx heterostructures on black phosphorus for wastewater remediation

Electrocatalytic urea oxidation reaction (UOR) offers a sustainable route for wastewater remediation and energy-saving hydrogen production, yet its efficiency is hindered by the sluggish kinetics of conventional nickel-based catalysts following an indirect oxidation mechanism. Here, we report a Mo-regulated Ni 2 P-MoO x heterostructure anchored on black phosphorus (BP) nanosheets, synthesized via an innovative electrolysis-solvothermal strategy, which shifts the UOR pathway from indirect to direct oxidation. Unlike traditional NiOOH-mediated processes, which require prior Ni 2 + oxidation, the in-situ Raman and LSV results indicate that this catalyst enables urea oxidation at unprecedentedly low potentials (1.31 V vs. RHE at 10 mA cm −2 ) before Ni 2+ self-oxidation, thereby reducing the overpotential by 245 mV relative to oxygen evolution. Advanced in-situ characterizations ( In-situ FTIR, In-situ Raman , In-situ EIS) and electronic structure analyses elucidate that Mo dopants with electron-deficient 4d orbitals synergistically enhance urea adsorption via carbonyl coordination and optimize charge transfer through interfacial electronic coupling with Ni 2 P, while phosphorus modulates the d-band center. This unique configuration promotes the direct dehydrogenation of adsorbed urea by electrophilic OH species, accelerates C–N cleavage, and minimizes harmful byproducts. This Ni 2 P-MoO x /BP catalyst sustains 55 h operation at 50 mA cm −2 , demonstrating exceptional stability. This work establishes a paradigm for steering reaction mechanisms through electronic engineering, offering transformative insights for designing energy-efficient electrocatalysts for complex molecule valorization.