Self-optimizing interface engineering with simultaneous activation of surface lattice oxygen for enhanced electrocatalytic water oxidation

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Iron vanadium (FeV)-based bimetallic oxides/hydroxides are promising electrocatalysts for water splitting. However, during the continuous OER process, most FeV catalysts are subjected to violent lattice distortion, resulting in a large amount of VOx dissolved into the electrolyte. Here, we propose an innovative material design strategy that not only replenishes the leaching V site of FeV-LDHs but also promotes the formation of VOOH on the surface, thereby establishing a self-optimizing interfacial interaction between VOOH and FeV-LDHs. The vacancies generated by interfacial rearrangement promote the adsorption of oxygen intermediates, while also contributing to a regulated electronic structure of Fe and V. Moreover, the presence of shared V–O bonds between VOOH and FeV-LDHs serves as an efficient charge transfer pathway, which not only stabilizes the high valence states of V but also enhances the activity of surface lattice oxygen in the OER process. Furthermore, the continuous adsorption of OH− promotes the formation of more oxygen vacancies in the catalyst system, thereby facilitating the deprotonation process and the production of O2. As a result, the VOOH/FeV-LDHs demonstrate exceptional OER performance, requiring a mere 158 and 217 mV overpotential to achieve current densities of 10 and 200 mA cm−2, respectively.