Cationic Defect Engineering in Perovskite LaCoMnO for Enhanced Electrocatalytic Oxygen Evolution.

The urgent need to promote the development of sustainable energy conversion requires exploration of highly efficient oxygen evolution reaction (OER) electrocatalysts. Defect engineering is a promising approach to address the inherent low electrical conductivity of metal oxides and limited reaction sites, for use in clean air applications and as electrochemical energy-storage electrocatalysts. In this article, oxygen defects are introduced into LaCoMnO perovskite oxides through the A-site cation defect strategy. By tuning the content of the A-site cation, oxygen defect concentration and corresponding electrochemical OER performance have been greatly improved. As a result, the defective LaCoMnO (LCMO) catalyst exhibits exceptional OER activity with an overpotential of 350 mV at 10 mA cm, approximately 120 mV lower than that of the pristine perovskite. This enhancement can be attributed to the increase in surface oxygen vacancies, optimized e occupation of transition metal at the B-site, and enlarged Brunauer-Emmett-Teller surface area. The reported strategy facilitates the development of novel defect-mediated perovskites in electrocatalysis.