Direct methanol fuel cells (DMFCs) are promising energy conversion devices, which can provide high efficiency and energy density, and as such, have been studied intensively. Due to the poisoning of Pt catalysts during methanol oxidation, various co-catalysts have been studied. Ruthenium has been studied extensively and good results have been obtained. More recently various oxide materials have been proposed and studied. Of these materials, rare earth metal oxides have been shown to be promising co-catalysts, although of the various oxides, CeO₂ has perhaps received most attention.

In this study, praseodymium oxide containing catalyst materials have been synthesised and characterized. Praseodymium oxide containing nanocatalysts were obtained via deposition of praseodymium hydroxide onto a carbon support material and calcination of the resulting material. Thereafter, platinum nanoclusters were deposited onto the praseodymium oxide containing composite material by impregnation of the Pt precursor into the support material and further reduction with hydrogen.

The studied materials were electrochemically characterized using rotating disk electrode, cyclic voltammetry, chronoamperometry and electrochemical impedance spectroscopy methods. Physical properties of the materials were characterized using X-ray diffraction, thermogravimetric analysis, scanning electron microscopy with EDX, inductively coupled plasma mass spectrometry and specific surface area measurements.

The studied materials exhibit high currents for methanol oxidation even at low Pt loadings. Compared to a commercial Pt-C(Vulcan) material, the overpotential was drastically reduced, and the peak potential for methanol oxidation is at E = 0.15 V vs mercury-mercurous sulfate electrode.

The good results of the study are a continuation of the investigation of nanocatalysts containing rare earth metal oxides for electrooxidation of alcohols.

Acknowlegements

This work was supported by the EU through the European Regional Development Fund Project TK141 “Advanced materials and high-technology devices for energy recuperation systems” (2014-2020.4.01.15-0011) and by the Estonian Research Council (institutional research grant IUT20-13, and PUT1581). P. Valk thanks Estonian Students Fund in USA for financial support.