Manganese-facilitated dynamic active-site generation on Ni₂P with self-termination of surface reconstruction for urea oxidation at high current density

Electrochemical urea oxidation reaction (UOR) suffers from sluggish reaction kinetics due to its complex 6-electron transfer processes combined with conversion of complicated intermediates, severely retarding the overall energy conversion efficiency. Herein, manganese-doped nickel phosphide nanosheets (Mn-Ni2P) are constructed and employed for driving UOR. Comprehensive analysis deciphers that Mn doping could efficiently accelerate the surface reconstruction of Mn-Ni2P electrode, generating highly reactive NiOOH-MnOOH heterostructure with local nucleophilic and electrophilic regions. Such unique structure could accelerate the targeted adsorption and activation of C and N atoms, promoting fracture of C-N bond in urea. In addition, moderate Mn doping could efficiently enhance the adsorption capacities of urea molecules and some key intermediates, and minish the energy barrier for *CO2 desorption, accelerating refreshing of the catalyst. Consequently, the Mn-Ni2P electrode exhibits excellent UOR catalytic activity, achieving an industrial-level current density of 1000 mA cm-2 at 1.46 V (vs. RHE).