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

Ternary mixed oxides of Fe, Co, and Mo with composition FexCo1-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 Fe0.5Co0.5MoO4. The Tafel slopes at low overpotentials were close to 40 mV with each oxide catalyst.

► Ternary mixed oxides were prepared by partial replacement of Co by Fe in the CoMoO4.
► Molecular formulae of the oxides were FexCo1-xMoO4(x = 0.25, 0.50, & 0.75).
► Prepared oxides were characterized as electrocatalysts for OER in alkaline solutions.
► The apparent electrocatalytic activity and specific surface area increased with Fe.
► The greatest electrocatalytic effect was observed with Fe = 0.25.