Tailoring the cationic and anionic sites of LaFeO3-based perovskite generates multiple vacancies for efficient water oxidation

Abstract

Perovskite transition metal oxides with ABO₃ structure are considered as potential alternative non-precious metal electrocatalysts for designing highly active and durable electrocatalysis for the oxygen evolution reaction (OER). Herein, we successfully enable LaFeO₃ coated on nickel foam (denoted LFO@NF) perovskite with impressive OER activity by systematically tailoring the Fe cation sites and the introduction of oxygen vacancies. The cationic site involves dual cation modulation with Cr and Mo, which creates lattice distortions inducing strong electronic interaction, while the anionic site entails reduction via a hydrogen-treatment process, creating oxygen vacancy sites to improve the electronic conductivity of the perovskite oxide. As a result, the optimized LFO-based catalyst, specifically hydrogenated LaFe_0.75Cr_0.15Mo_0.10O₃-coated on the nickel foam (denoted H-LFCMO@NF), requires the lowest overpotential of 263 mV at 10 mA cm⁻², and has superior kinetics and excellent stability, which are superior to its counterparts. Theoretical analysis also confirmed that the tailoring of the LFO@NF perovskite leads to an increase in the exposure of active sites, optimization of the adsorption energy of reaction intermediates and enhanced electronic conductivity. This work may provide a promising concept to enhance the performance of LFO-based perovskite electrocatalysts for alkaline OER and beyond.