Engineering oxygen vacancies in perovskite oxides by in-situ electrochemical activation for highly efficient nitrate reduction

Perovskite oxides have emerged as a new category of catalysts for NO 3 RR, yet their low intrinsic catalytic activity results in unsatisfactory performance. Oxygen vacancy engineering has recently been found to be effective for improving the NO 3 RR performance of perovskite oxides. Herein, a novel and efficient strategy of electrochemical activation for in-situ oxygen vacancies (OVs) creation in perovskite oxide La 0.9 FeO 3-δ was reported. The results showed that the NO 3 − -N removal rate increased 2.6-fold on activated La 0.9 FeO 3-δ in comparison to pristine La 0.9 FeO 3-δ . The enhanced NO 3 RR performance was attributed to the presence of more OVs, which served to increase the adsorption energy of NO 3 − while also promoting atomic H* formation for NO 3 − -N hydrogenation. Furthermore, a continuous experiment lasting 240 h found the activated La 0.9 FeO 3-δ exhibited extremely high stability. Additionally, we demonstrated that the electrochemical activation method was applicable to other typical perovskite oxides, such as LaCoO 3 , indicating its generalizability. This study provides a simple and scalable approach for the preparation of a high-performance perovskite oxide-type electrocatalysts for NO 3 RR.