Iron molybdates as electrocatalysts for O2 evolution reaction in alkaline solutions

Iron molybdates with [Mo]/[Fe] ratios 1.0, 1.5 and 3.0 have been prepared by a co-precipitation method and produced in the form of thin films on a Ni support. These oxides follow the monoclinic crystal geometry. The study shows that the new oxide is highly active towards the oxygen evolution reaction in alkaline solutions and that its activity seems to depend upon the molar ratio of Mo and Fe in the oxide. The oxide with [Mo]/[Fe] = 1.0 is observed to exhibit the greatest electrocatalytic activity. The reaction order with respect to OH− concentration has been found to be fractional (0.8–1.6). The Tafel slopes at low potentials were close to 35 mV.