Metastable Ni₂P Phase Transformation via Ce-Mo Dual-Modulation for Efficient Urea Electrolysis

Electrocatalytic urea oxidation reaction (UOR) enables simultaneous wastewater purification and energy-efficient hydrogen production, despite facing slow kinetics and competing oxygen evolution. Herein, a high-performance Ce/Ni_2−xMo_xP catalyst was synthesized through Ce and Mo dual-modulation to dynamically regulate Ni-P phase transitions and construct atomic-scale electron transfer networks. Investigations reveal that the Ce³⁺/Ce⁴⁺ redox cycle triggers oxygen vacancy formation and steers the transition from stable Ni₃P to metastable Ni₂P, while Mo⁶⁺ acts as an electron acceptor to optimize the electronic structure of Ni sites. Their synergistic interaction significantly lowers the phase transition barrier and boosts urea adsorption/activation. The catalyst achieves a current density of 100 mA cm^‒2 at a low potential of 1.32 V for UOR and demonstrates exceptional stability. Moreover, a urea electrolysis system constructed based on the optimized Ce/Ni_2−xMo_xP bifunctional catalyst reaches 400 mA cm^‒2 at just 1.68 V, significantly outperforming conventional water electrolysis, as well as maintaining operation for over 460 h at 500 mA cm^‒2 with a minimal decay rate of 0.11 mV h^‒1. This work elucidates the atomic-scale mechanism of Ce-Mo cooperative regulation of electronic structure and phase transformation, providing a new strategy for designing efficient non-noble-metal electrocatalysts and advancing the industrialization of urea electrolysis.