Activating Lattice Oxygen in Layered Lithium Oxides through Cation Vacancies for Enhanced Urea Electrolysis

Abstract Despite the fact that high‐valent nickel‐based oxides exhibit promising catalytic activity for the urea oxidation reaction (UOR), the fundamental questions concerning the origin of the high performance and the structure–activity correlations remain to be elucidated. Here, we unveil the underlying enhanced mechanism of UOR by employing a series of prepared cation‐vacancy controllable LiNiO 2 (LNO) model catalysts. Impressively, the optimized layered LNO‐2 exhibits an extremely low overpotential at 10 mA cm −2 along with excellent stability after the 160 h test. Operando characterisations combined with the theoretical analysis reveal the activated lattice oxygen in layered LiNiO 2 with moderate cation vacancies triggers charge disproportion of the Ni site to form Ni 4+ species, facilitating deprotonation in a lattice oxygen involved catalytic process.