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 CeO2 toward robust alkaline HER. The induced lattice compression and increased oxygen vacancy (Ov) concentration in CeO2 synergistically improve the water dissociation on Ov sites and sequential hydrogen adsorption at activated Ov‐neighboring sites, leading to significantly enhanced HER kinetics. Meanwhile, Y doping offers stabilization effect on Ov by its stronger Y─O bonding over Ce─O, which endows the catalyst with excellent stability. The Y,Co‐CeO2 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‐CeO2 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.

Engineering Water-Lotus-like Iridium–Cobalt Carbonate Hydroxides on Plasma-Treated Carbon Fibers for Enhanced Electrocatalytic Oxygen Evolution

“…Figure 3f exhibits a symmetric peak at g = 2.003 for all electrocatalysts, indicating unpaired electrons in the O v . Meanwhile, the EPR signal intensity of IrO 2 -P-CoCH/PCC is significantly stronger than that of IrO 2 -CoCH/PCC, further verifying the existence of O v sites, 45,46 which manifests that the intermediate etched by plasma can effectively increase the formation of oxygen vacancies. Therefore, the synergistic effect of heterointerface phases and the formed O v are quite helpful for improving the electrocatalytic activity of IrO 2 -P-CoCH/PCC, causing a high OER performance.…”