In situ synthesis of manganese oxide/iron oxide/polyaniline composite catalyst for oxygen evolution reaction

Non-noble-metal-based electrocatalysts possessing high inherent activity toward the oxygen evolution reaction (OER) are highly desired. Considering the synergetic effect of different metal sites and the high conductivity of polyaniline (PANI), here we report polymer-based bimetallic ternary nanocomposite (Fe–Mn@PANI), which is synthesized by in situ polymerization method. Fe–Mn@PANI/NF has shown the best OER activity with lower onset potential (1.46 V vs RHE), low overpotential of 353 mV at 10 mA cm⁻², and Tafel slope of 68 mV dec⁻¹. The remarkable outcomes can be attributed to the synergistic effect of the two distinct metals and PANI, which particularly has a unique π-conjugated structure and abundant nitrogen species with lone pairs of electrons providing a consistent flow of ions across entire surface of composite and also improving OH⁻ adsorption capacity which makes it a highly efficient, cost-effective, and stable catalyst with improved performance of the OER.