Reversible oxygen vacancies in tungsten oxide-activated heterocatalysts enable stable electrocatalytic oxygen evolution

Abstract

Interfacial and oxygen vacancy engineering are promising strategies to tune the electronic structure of electrocatalysts and modulate the surface absorption/desorption of reactants, thereby enhancing oxygen evolution reaction (OER) activity and stability. Herein, we present a hierarchical assembly strategy to mitigate Co dissolution and stabilize oxygen vacancies triggered by strong electronic interactions via constructing elaborately W₁₈O₄₉/Co₃(BO₃)₂ heterostructure. Multiple in-situ characterization technologies confirm that this synergy enables the formation of active centers and accelerates charge transfer, resulting in improved oxygen evolution activity. Importantly, the incorporation of W₁₈O₄₉ provides dynamically reversible oxygen vacancies that enhance catalysis durability, stabilizing the active Co sites during OER processes. Theoretical calculations further reveal that the interfacial electronic interaction enhances charge transfer, suppresses cobalt ions demetalization, and stabilizes oxygen vacancy within the crystal structure. Owing to the stabilized Co sites and O sites, the W₁₈O₄₉/Co₃(BO₃)₂ exhibits high activity (251 mV at 10 mA cm⁻²) and outstanding stability, with minimal degradation after 100 hours of operation. This work offers valuable insights into designing highly active and durable OER catalysts by leveraging heterointerfacial and oxygen vacancy engineering.