Effect of TiOsub(2) content on ethanol electrooxidation in alkaline media using Pt nanoparticles supported on physical mixtures of carbon and TiOsub(2) as electrocatalysts

Abstract

Pt nanoparticles supported on physical mixtures of carbon and TiO2 (Pt/(C+TiO2) electrocatalyst) were tested for ethanol electrooxidation in alkaline media. The electrocatalysts were prepared with different C/TiO2 mass ratios using borohydride as reducing agent. X-ray diffraction patterns of the obtained materials showed the peak characteristic of Pt facecentered cubic (fcc) structure, carbon, and TiO2 phases. Transmission electron micrographs showed metal nanoparticles distributed preferentially over TiO2 support with average particle size between 5 and 7 nm for all electrocatalysts. The cyclic voltammograms of Pt/(C+TiO2) electrocatalysts in alkaline media showed a decrease of Pt surface area with the increase of TiO2 content. The electrooxidation of ethanol suggests the Pt/(C + TiO2) (40:60) as the most promising electrocatalyst for use in fuel cells since it presents almost the same current density value as that of the others and also slower current density decay in chronoamperometry. Moreover, TiO2 provides oxygen species to promote the CO oxidation, resulting in more activity.