Cobalt doping in LaMnO3 perovskite catalysts – B site optimization by solution combustion for oxygen evolution reaction

Abstract

The development of a highly active, stable, and cost-effective electrocatalyst for oxygen electrocatalysis has created a revolution in the field of sustainable energy research. Among them, noble metal free Lanthanum based perovskite got much attention as a catalyst for Oxygen Evolution Reaction (OER) due to their flexibility in the cation arrangement and tailorable electronic and ionic properties. In this study a rapid and cost effective solution combustion technique was used for the preparation of LaMn1-xCoxO3 (x = 0, 0.2, 0.4, 0.6, 0.8 and 1). Following this method, Co doped LaMnO3 has been successfully prepared. From the results of X-ray photoelectron spectroscopy (XPS), it was found that the high Co content levels activate the surface enhancement in B-site cation in their respective higher oxidation state (Mn4+ and Co3+). It was observed that, compared with other catalysts, LaMn0.2Co0.8O3 had good stability and shows acceptable OER activity with a lower overpotential of 430 mV at 10 mA/cm2 and a lower Tafel slope of value 57.95 mV/dec. This study provides a simple cost effective synthesis route for the preparation of perovskite material and also offers a path for enhancing OER activity by B-site cation substitution.