Manipulation of Electrochemical Surface Reconstruction on Spinel Oxides for Boosted Water Oxidation Reaction

Water electrolysis presents possibilities for pure hydrogen production, a method widely recognized as a carbon-neutral and ecofriendly substitute for fossil fuels. However, the oxygen evolution reaction (OER) at the anode suffers from intrinsically sluggish kinetics and low efficiency. Spinel oxides are widely studied due to their low cost, tunable valence states, and rich compositions, but their development as promising OER electrocatalysts is still impeded by limited exposure of active sites and poor intrinsic activity. In general, many transition metal-based oxides (TMOs) would undergo surface reconstruction under high anodic potentials, and the reconstructed high-valence metal oxyhydroxides (MOOHs) on the surface are considered to be the true active species. Hence, understanding the relationships between electronic structures and dynamic reconstruction ability plays a crucial role in enhancing electrocatalytic performance. In this review, recent progress in modulating surface reconstruction of spinel oxides is comprehensively summarized, accompanied by advanced techniques to visually monitor this dynamic process. Furthermore, some remaining challenges and potential perspectives to tailor the surface behavior of spinel oxides are also pointed out. This review aims to offer insights into surface reconstruction on spinel-type oxides and provide valuable guidelines for the design of efficient and durable OER electrocatalysts.