Preparation of Pt supported on WO3–C with enhanced catalytic activity by microwave-pyrolysis method

The WO3–C hybrid materials are prepared by intermittently microwave-pyrolysis using ammonium tungstate as the precursor, and then Pt nano-particles are deposited by microwave-assited polyol process on WO3–C. The TEM images show the dispersion of ∼10 nm WO3 particles size supported on carbon and ∼3 nm Pt metal crystallites supported on WO3–C. XRD results illustrate that WO3 presented as monoclinic phase and the content of WO3 in WO3/C and Pt/WO3–C catalysts is further characterized by EDAX. Furthermore, XPS characterizations indicate that the interaction between Pt and WO3 is dramatically enhanced after heat treatment at 200 °C. The activities of Pt/WO3–C for the electrochemical oxidation of methanol are compared with Pt/C in acid solution by cyclic voltammetry, CO-stripping and chronoaperometry. Pt/WO3–C catalyst calcined at 200 °C exhibits the highest activity per electrochemical active surface area for methanol oxidation and is 60 mV more negative for CO electro-oxidation than that of Pt/C and Pt/WO3–C without heat treatment. The great enhancement of electrochemical performance may be due to the improvement of the synergistic effect between Pt and WO3 in Pt/WO3–C catalyst after heat treatment.