Laser direct writing of graphene-encapsulated MoNi4 nanoparticles on carbon cloth as a self-supporting electrode for enhanced electrochemical urea oxidation

Abstract

Nickel-based catalysts have garnered significant attention for the urea oxidation reaction (UOR), primarily due to the pivotal role of NiOOH as the active phase. However, practical applications are often hindered by poor electrical conductivity and sluggish Ni2⁺/Ni3⁺ redox transitions. In this work, we present a self-supporting electrode composed of graphene encapsulated Mo-doped nickel nanoparticles grown on carbon cloth (NiMo/G/CC). The strategic Mo doping not only enhances the formation of NiOOH by accelerating the Ni2⁺→Ni3⁺ transition but also modulates the electronic structure in synergy with graphene’s high conductivity. Consequently, the optimized electrode achieves an impressive current density of 100 mA cm⁻2 at 1.38 V vs. RHE, outperforming many state-of-the-art UOR catalysts. Furthermore, the protective graphene encapsulation greatly improves electrode stability under prolonged operation.