Defect engineering for surface reconstruction of metal oxide catalysts during OER

The bigger pictureChallenges and opportunities:•The scarcity of active sites limits the large-scale application of metal oxides as commercial oxygen evolution reaction (OER) catalysts. However, the rational design of defect structures can boost their catalytic activity•The precise design of catalyst defect structures requires a comprehensive understanding of the structure-activity relationship between defects and OER performance. Current research primarily focuses on the correlation between defects and thermodynamic parameters. However, our understanding of the intrinsic relationship between defects and the kinetics and mechanisms of OERs remains limited•In the adsorbate evolution mechanism (AEM), defect structures can accelerate the evolution of active surfaces, promote OH⁻ adsorption and deprotonation, and facilitate the desorption of the product O₂. In the lattice oxygen intermediate mechanism (LOM), defect structures can enhance the covalency of metal–oxygen bonds and provide OH⁻ adsorption sites, facilitating their involvement in lattice oxygen oxidation processesSummaryThe development of electrochemical processes, such as water electrolysis for hydrogen production and rechargeable metal-air batteries, offers promising solutions to the energy crisis and environmental pollution. However, challenges like sluggish oxygen evolution reaction (OER) kinetics, high costs of precious metal catalysts, and scarce active sites in transition metal oxides hinder large-scale commercial applications. Defect engineering has emerged as a promising strategy to optimize transition metal oxides by improving their electronic structure, conductivity, and active site availability. Early research focused on static thermodynamic parameters, such as impedance, overpotential, and band gap, neglecting dynamic factors like catalyst surface restructuring and mechanism transformation during reactions. This perspective highlights the intrinsic connection between defect structures, catalyst surface reconstruction, and reaction mechanisms. It also discusses the need for advanced experimental and theoretical computational studies to better understand the surface evolution of catalysts during OERs.Graphical abstract