Elctrocatalytic oxygen evolution reaction on Mg, Al and Fe doped spinel oxides

Abstract

Metal doped cobalt-based spinel type catalysts prepared by co-precipitation route are considered as suitable candidates for OER, ORR, metal air batteries, fuel cells, detoxification of water, etc. For the purpose, metal doped oxides with formula MCo2O4 (M= Mg, Al and Fe) have been prepared by thermal decomposition of their metal carbonate precipitates and characterized by IR, XRD, CV, EIS and Tafel polarization techniques. The FTIR spectra of oxides show absorption bands ~ 650 cm-1 and ~ 560 cm-1 for respective stretching and bending modes of vibration of Co-O bond at octahedral sites and formation of nano-size (~ 18 nm) single phase cubical crystal with spinel geometry is confirmed by powder XRD patterns. The cyclic voltammetric curves of oxide electrodes in 1 M KOH solution showed a redox peak at Eo = 434 -516 mV for Co2+/Co3+ reactions. The electrocatalytic activity of oxide electrodes for oxygen evolution reaction in 1 M KOH at 25 °C was also studied by Tafel polarization technique and polarization curve of each oxides showed two Tafel slopes and order of OER is unity.