Cationic Defect Engineering in Perovskite La 2 CoMnO 6 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 La 2 CoMnO 6-δ 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 La 1.8 CoMnO 6-δ (L 1.8 CMO) catalyst exhibits exceptional OER activity with an overpotential of 350 mV at 10 mA cm -2 , approximately 120 mV lower than that of the pristine perovskite. This enhancement can be attributed to the increase in surface oxygen vacancies, optimized e g 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.