XAFS study on a photodeposition process of Pt nanoparticles on TiO2 photocatalyst

A photodeposition process of Pt metal particles on anatase TiO2 in the aqueous solution of H2PtCl6 (precursor) and methanol (reductant) was studied using transmission electron microscopy, UV-vis spectroscopy and X-ray absorption fine structure spectroscopy. These analyses proposed the photodeposition mechanism of Pt on TiO2 by the photogenerated electrons: the photo-assisted adsorption of Pt4+ complexes on TiO2 through the ligand exchange at the initial stage, followed by the successive rapid reduction of Pt4+ to Pt0 to grow the Pt metal particles, which gives small and almost uniform size of Pt metal nanoparticles.