Characterization of Au/TiO2 nanocomposites by XPS

Au/TiO2 nanocomposites were prepared by a hybrid route consisting in the RF sputtering of gold on porous titania xerogels [TiOx(OH)y(OR)z] obtained by means of the Sol-Gel route. In particular, titania substrates were prepared on silica slides by dip-coating starting from ethanolic solutions of Ti(OPri)4 (OPri=iso-propoxy) and Hacac (2,4-pentanedione). Subsequently, Au depositions were performed on the as-prepared xerogels in Ar plasmas at temperatures as low as 60°C. The resulting systems were finally annealed in air for 1 h at 200, 400 and 600°C, with the aim of tailoring gold distribution in the titania matrix. Their structure, composition and morphology were studied by Glancing Incidence X-Ray Diffraction (GIXRD), optical absorption spectroscopy and X-ray Photoelectron Spectroscopy (XPS). This work is dedicated to the XPS characterization of a representative Au/TiO2 sample analyzed after annealing in air at 600°C. In particular, detailed scans for the Au4f, Ti2p, O1s and C1s regions and related data are presented and discussed. The obtained results point to the presence of metallic gold and TiO2, with carbon contamination limited only to the outermost layers.