International Journal of Hydrogen Energy, Vol.38, No.31, 13587-13595, 2013
Manganese molybdate and its Fe-substituted products as new efficient electrocatalysts for oxygen evolution in alkaline solutions
Pure and Fe-substituted manganese molybdates with nominal compositional formula Fe Mn1-xMoO4 (x = 0, 0.25, 0.50 and 0.75) have been prepared by a co-precipitation method at pH approximate to 2 and characterized by FT-IR, XRD, XPS, TEM, electrochemical impedance and polarization techniques. The oxygen evolution reaction (OER) study reveals that Fe substitutions from 0.25 to 0.75 mol for Mn increase the apparent electrocatalytic activity of the base oxide showing maximum with 0.5 mol Fe.AtE = 0.60 V vs.Hg/HgO in 1M KOH at 298K, the apparent activity of the base oxide increased similar to 58 times. It is observed that on Fe addition, the Tafel slope decreases from similar to 60 to similar to 35 mV, however, the order of the OER with respect to OH(-)concentration as observed similar to 2 on the base oxide (i.e. MnMoO4) does not change. Copyright (C) 2013, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.