Coupling Interface Constructions of FeNi₃‑MoO₂ Heterostructures for Efficient Urea Oxidation and Hydrogen Evolution Reaction

Urea electrolysis has prospects for urea-containing wastewater purification and hydrogen (H₂) production, but the shortage of cost-effective catalysts restricts its development. In this work, the tomentum-like FeNi₃-MoO₂ heterojunction nanosheets array self-supported on nickel foam (NF) as bifunctional catalyst is prepared by facile hydrothermal and annealing method. Only 1.29 V and −50.8 mV is required to obtain ±10 mA cm^–2 for urea oxidation and hydrogen evolution reaction (UOR and HER), respectively, showing great bifunctional catalytic activity. For overall urea electrolysis, it only needs 1.37 V to reach 10 mA cm^–2 and can last at 100 mA cm^–2 for 70 h without obvious activity attenuation, showing outstanding durability. Coupling interface constructions of FeNi₃-MoO₂ heterostructures, novel morphology with a mesoporous and self-supporting structure could be the reason for this good performance. This work thus proposes a promising catalyst for boosting UOR and HER to realize efficient overall urea electrolysis.