Lattice Strain with Stabilized Oxygen Vacancies Boosts Ceria for Robust Alkaline Hydrogen Evolution Outperforming Benchmark Pt

Abstract Earth‐abundant metal oxides are usually considered as stable but catalytically inert toward hydrogen evolution reaction (HER) due to their unfavorable hydrogen intermediate adsorption performance. Herein, a heavy rare earth (Y) and transition metal (Co) dual‐doping induced lattice strain and oxygen vacancy stabilization strategy is proposed to boost CeO 2 toward robust alkaline HER. The induced lattice compression and increased oxygen vacancy (O v ) concentration in CeO 2 synergistically improve the water dissociation on O v sites and sequential hydrogen adsorption at activated O v ‐neighboring sites, leading to significantly enhanced HER kinetics. Meanwhile, Y doping offers stabilization effect on O v by its stronger Y─O bonding over Ce─O, which endows the catalyst with excellent stability. The Y,Co‐CeO 2 electrocatalyst exhibits an ultra‐low HER overpotential (27 mV at 10 mA cm −2 ) and Tafel slope (48 mV dec −1 ), outperforming the benchmark Pt electrocatalyst. Moreover, the anion exchange membrane water electrolyzer incorporated with Y,Co‐CeO 2 achieves excellent stability of 500 h under 600 mA cm −2 . This synergistic lattice strain and oxygen vacancy stabilization strategy sheds new light on the rational development of efficient and stable oxide‐based HER electrocatalysts.