A comparative study of electrocatalytic performance of metal molybdates for the water oxidation

摘要

Binary mixed oxides of molybdenum and a metal of the first-row transition metals with compositional formulae, MMoO4 (where M = Cr, Fe, Mn, Co, Ni, Cu or Zn), were prepared by a microwave-assisted co-precipitation method and their electrocatalytic activities have been investigated for oxygen evolution reaction (OER) in 1 M KOH. Materials were characterized for structural and electrocatalytic surface properties using FT-IR, XRD, TEM, BET, XPS, cyclic voltammetry (CV) and anodic Tafel polarization techniques. The crystallite size of oxides ranged between similar to 17 and similar to 41 nm. For electrochemical studies, oxides obtained in powders form were produced in the thin-film form on the pretreated glassy carbon (GC) support. It has been observed that among electrocatalysts investigated, the CoMoO4/GC electrode was the greatest OER active while that the MnMoO4/GC electrode was the least active. The OER produced low Tafel slopes, similar to 36, similar to 43 and similar to 46 mV respectively on FeMoO4, CoMoO4 and CuMoO4 while it showed the higher Tafel slopes on CrMoO4(similar to 57 mV), NiMoO4(similar to 71 mV) and MnMoO4(similar to 89 mV). (C) 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.