Unveiling the electron configuration-dependent oxygen evolution activity of 2D porous Sr-substituted LaFeO3 perovskite through microwave shock

Abstract

Developing an efficient and stable oxygen evolution reaction (OER) catalyst is beneficial in various energy conversion and storage applications for achieving the “Carbon Neutrality” goal. Among the iron-based perovskite oxides (AFeO₃), LaFeO₃ stands out as a preferred catalyst for electrocatalytic OER due to its exceptional selectivity in oxygen bonding at the A-site. The introduction of A-site substitution and controlled morphological engineering in perovskite structures has proven effective in enhancing the electrical conductivity and intrinsic catalytic activity. Nevertheless, the conventional A-site substitution approach often involves prolonged high-temperature calcination, leading to the agglomeration of nanostructures, particularly in two-dimensional (2D) porous configurations. Herein, we introduce a novel method for synthesizing 2D porous LaFeO₃ perovskite with A-site Sr substitution using microwave shock. This microwave technique capitalizes on the benefits of transient heating and cooling, enabling simultaneous construction of 2D porous morphology and precise regulation of Sr substitution in one step. By conducting theoretical simulations of the electron configuration and analysis of crystal structure, we unveil the impact of Sr substitution on the OER activity of 2D porous LaFeO₃. The synthesized La_0.2Sr_0.8FeO₃ (LSFO-8) catalyst exhibits an exceptional overpotential of 339 mV at 10 mA cm⁻² and a small Tafel slope of 56.84 mV dec⁻¹ in alkaline electrolyte. This investigation provides a fresh perspective for the design and engineering of electronic configuration in highly active 2D perovskite materials.