Synthesis and characterization of sol-gel Pt/TiO2 catalyst

Pt/TiO2 catalysts with 1.0 wt% Pt were prepared by using the sol-gel technique with Ti(OBut)(4) and platinum acetylacetonate. The catalysts were prepared in only one step, without the need to reduce the sample in hydrogen. All fresh samples have three nanophases: rutile (the majority phase), anatase, and platinum. Their crystalline structure was obtained by X-ray powder diffraction and refined with the Rietveld technique. Samples were also characterized by FTIR spectroscopy. Platinum promoted the formation of rutile. This could stem from either the presence of PtO2, which has the rutile structure, as an intermediate phase, or the platinum-catalyzed dehydroxylation of anatase. Although PtO2 and rutile have the same crystalline structure, platinum atoms did not go into the crystalline structure of rutile. (C) 1996 Academic Press, Inc.