Effect of Ti(IV) loading on CO oxidation activity of gold on TiO2 doped amorphous silica

Amorphous SiO2, doped with various amount of TiO2, was used as support for gold nanoparticles. Gold was deposited through the controlled sol formation technique. The effect of the TiO2 loading on the structural and surface properties was investigated by transmission electron microscopy, X-ray diffraction, Raman and X-ray photoelectron spectroscopy. The catalytic behavior was tested in the oxidation of CO. A significant enhancement in the activity was observed for the gold supported on mixed oxide with low TiO2 loading. On the basis of characterization data, the positive effect is assigned to the electronic modification of the Ti(IV) of the newly formed TiOSi bonds.