Effect of cation substitution in MnCo2O4 spinel anchored over rGO for enhancing the electrocatalytic activity towards oxygen evolution reaction (OER)

Developing an efficient and durable electrocatalyst for catalyzing oxygen evolution reaction in electrochemical water splitting application is greatly desired and challenging. Herein, a simple and facile strategy was followed to prepare Ni-substituted MnCo2O4/rGO nanocomposite as an electrocatalyst for oxygen evolution reaction (OER). The structural and morphological analyses show the successful bonding between spinel-carbon hybrid. Nickel substitution and addition of rGO disclose a drastic change in the catalytic activity of the same towards OER. Among all the electrocatalysts, Mn1-xNixCo2O4/rGO with x = 0.6 exhibits low overpotential of 250 and 290 mV for attaining the current density of 10 mA/cm(2) before and after potential cycling respectively. It also exhibits low onset potential of 1.48 V with a Tafel slope of value 78 mV/dec. The electrocatalyst also shows excellent stability, high ECSA and roughness factor (R-f) which are responsible for enhanced OER performance. These properties confirm that the present hybrid material would be an excellent electrocatalyst for catalyzing OER for hydrogen energy production. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.