Mn-doped nickeltitanate (Ni1−xMnxTiO3) as a promising support material for PdSn electrocatalysts for methanol oxidation in alkaline media

Abstract

Nickeltitanate (Ilmenite) has been prepared with stoichiometric variation by substituting Mn in the ‘A’ site, using the sol–gel method in a highly active form. The PdSn electrocatalyst was then impregnated with nickeltitanate by a microwave-assisted polyol method. The physiochemical characterisation of the synthesized electrocatalyst PdSn–Ni_1−xMn_xTiO₃ was done by X-ray diffractometry, UV-visible spectrophotometry, Raman spectroscopy and transmission electron microscopy. The elemental composition was obtained using energy dispersive spectra which confirmed the presence of Ni, Mn, Ti, O, Pd and Sn. Electrochemical characterization using cyclic voltammetry and polarization experiments showed that the synthesized PdSn–Ni_1−xMn_xTiO₃ exhibited an enhanced catalytic activity and better stability in the alkaline medium, compared to conventional PdSn/C catalysts. It was observed that the charge transfers from the support material (Ni_1−xMn_xTiO₃) to the PdSn electrocatalyst boosted the oxidation reaction. By varying the methanol concentration from 0.5 M to 2.0 M, the resulting current density also varied from 129 to 151 mA cm⁻². This result demonstrated that the prepared material PdSn–Ni_1−xMn_xTiO₃/C electrocatalyst is an excellent candidate for the methanol oxidation reaction.