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

Earth-abundant metal oxides are usually considered as stable but catalytically inert towards 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 towards 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 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. This article is protected by copyright. All rights reserved.