Trimetallic Ni–Co–Fe Phosphide Heterostructure via Synergistic Electronic Modulation for Efficient and Stable Urea Oxidation Reaction

The development of efficient nonprecious metal electrocatalysts for the urea oxidation reaction (UOR) is critical to advancing sustainable hydrogen production while mitigating environmental pollution. Here, we report a trimetallic Ni2P/Fe2P/CoP heterostructured catalyst synthesized on nickel foam (NF) via a physical deposition and low-temperature phosphidation strategy. The synergistic coupling of Ni, Co, and Fe components optimizes electronic configurations, enhances urea adsorption energy, and facilitates intermediate (*COO–) desorption, while phosphorus doping promotes charge transfer and corrosion resistance. Notably, the catalyst achieves a current density of 100 mA cm–2 at a low potential of 1.395 V (vs RHE) in 1 M KOH + 0.2 M urea, with a Tafel slope of 27.22 mV dec–1, and an overpotential that is 72 mV lower than the OER. Structural characterization confirms the coexistence of Ni2P, Fe2P, and CoP phases with abundant heterointerfaces and uniform elemental distribution. The catalyst demonstrates exceptional stability over 100 h of continuous operation, attributed to robust electronic interactions and PO43–mediated proton-coupled electron transfer. This work provides a rational design strategy for cost-effective, high-performance UOR electrocatalysts, highlighting their potential for industrial hydrogen production and urea wastewater remediation.