Unveiling anion induced surface reconstruction of perovskite oxide for efficient water oxidation

Abstract

Perovskite oxides are a promising family of oxygen evolution reaction (OER) electrocatalysts. However, rational design of surface reconstruction on perovskite oxides to achieve high intrinsic activity is still a daunting challenge. Here, we demonstrate a facile anion defect approach to activate the surface reconstruction of perovskite oxide for OER. Experimental and theoretical investigations reveal that fluorine incorporation into LaNi0.75Fe0.25O3 (LNFO) perovskite with low vacancy formation energy facilitates surface transformation kinetics, creating electrochemically active oxyhydroxide layer. The reconstruction induced oxyhydroxide-perovskite heterostructure, in turn, enables a reduced energy barrier of OER relative to the pristine perovskite. As a demo, the optimized fluorine incorporated LNFO electrocatalyst exhibits an excellent OER performance with a low overpotential of 292 mV at 10 mA cm-2, significantly superior to the pristine LNFO and the benchmark IrO2 electrocatalysts. This finding offers new insights into activating surface reconstruction on perovskite oxide by engineering anion defect for water oxidation.