Platinum tungsten oxide (Pt–WO₃) nanoparticles: their preparation in glycol and electrocatalytic properties

A method to prepare supported nanoparticles of Pt–WO3 with composition control in nanoscales is presented. Transmission electron microscopy shows crystal domains in the nanoparticles, which have a narrow size distribution. Energy dispersive X-ray analyses performed in different regions show good uniformity in the Pt : W ratio, which correlates linearly with the Pt : W ratio in the precursor. Platinum is mostly present in the pure metallic state whereas tungsten is in the +6 oxidation state, as revealed by X-ray photoelectron spectroscopy. The Pt–WO3 nanoparticles supported on Vucan XC 72 carbon exhibit high activity for methanol oxidation at room temperature. The electrocatalytic activity varies with the Pt : W ratio with an optimum at 1 : 1. At this ratio, the activity is better than a commercial PtRu/C catalyst of equivalent platinum loading.