New ternary Fe, Co, and Mo mixed oxide electrocatalysts for oxygen evolution

Abstract

Ternary mixed oxides of Fe, Co, and Mo with composition Fe xCo1-xMoO4 (x = 0.25, 0.50 & 0.75) have been prepared by a co-precipitation method and investigated as electrocatalysts for the oxygen evolution reaction (OER) in alkaline solutions. The study indicates that partial replacement of Co by Fe in the CoMoO4 matrix increases the specific surface area as well as the apparent electrocatalytic activity of the oxide; the magnitude of increase being the greatest with x = 0.25. The order for the OER with respect to OH- concentration has been observed to be ∼2 on Fe0.75Co0.25MoO4 and ∼1 on Fe0.25Co0.75MoO4 and Fe 0.5Co0.5MoO4. The Tafel slopes at low overpotentials were close to 40 mV with each oxide catalyst. © 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.