Cation substitution of B-site in LaCoO3 for bifunctional oxygen electrocatalytic activities

LaCoO3-based materials are potential electrocatalysts with good activity and stability for the oxygen evolution reaction (OER) and oxygen reduction reaction (ORR). In this study, the cation of the Co site is substituted by Mn in LaCoO3, and samples with the composition LaMnxCo(1-x)O(3) (x = 0, 0.2, 0.4, 0.6, 0.8, and 1.0) are prepared. Electrocatalytic test results show that the electrocatalytic activities of the samples depend on the Mn concentration, and LaMn0.4Co0.6O3 simultaneously exhibits the best OER/ORR performance and stability. X-ray photoelectron spectroscopy results show that the introduction of Mn can significantly increase the content of highly active Mn4+ and Co3+. This result and the increased electrical conductivity evidenced by both, first-principles calculations and charge transfer resistance results, can explain the optimization of the oxygen catalytic activities. This study offers a feasible pathway for optimizing the performance of perovskite oxygen electrocatalysts by cation substitution. (c) 2021 Elsevier B.V. All rights reserved.