Published online by Cambridge University Press: 22 February 2011
The surface composition and electronic structure of carburized tungsten trioxide are investigated using X-ray photoelectron spectroscopy (XPS). The relationship between the surface composition and the catdlytic activity for methanol electro-oxidation is clarified. The tungsten carbide concentration in the surface layer increases with the carburization time. The formation of tungsten carbide enhances the catalytic activity. On the other hand, the presence of free carbon or tungsten trioxide in the surface layer reduces the activity remarkably. It is also shown that, the higher the electronic density of states near the Fermi level, the higher the catalytic activity.