OLEFIN METATHESIS CATALYST .1. ANGLE-RESOLVED AND DEPTH PROFILING XPSSTUDY OF TUNGSTEN-OXIDE ON SILICA

Model supports consisting of a thin layer of SiO2 on a silicon single crystal have been used to study the WO3/SiO2/Si (100) catalyst precurs or. Compared to the powder analogues, a drastic increase in spectral r esolution and detailed band structure is observed in the XPS spectra. Conventional XPS, angle dependent and depth profiling X-ray photoelect ron spectroscopy show the presence of two types of tungsten oxide on t he surface: microcrystallites of WO3 and a tungsten oxide monolayer ch emically bonded to the silica matrix.