Rational Design of Ag/TiO2 Nanosystems by a Combined RF-Sputtering/Sol-Gel Approach

The present work is devoted to the preparation of Ag/TiO2 nanosystems by an original synthetic strategy, based on the radio-frequency (RF) sputtering of silver particles on titania- based xerogels prepared by the sol–gel (SG) route. This ap- proach takes advantage of the synergy between the micropo- rous xerogel structure and the infiltration power characterizing RF-sputtering, whose combination enables the obtainment of a tailored dispersion of Ag-containing particles into the titania matrix. In addition, the system’s chemico-physical features can be tuned further through proper ex situ thermal treatments in air at 400 and 600°C. The synthesized composites are exten- sively characterized by the joint use of complementary techni- ques, that is, X-ray photoelectron and X-ray excited Auger electron spectroscopies (XPS, XE-AES), secondary ion mass spectrometry (SIMS), glancing incidence X-ray diffraction (GIXRD), field emission scanning electron microscopy (FE–SEM), trans- mission electron microscopy (TEM), electron diffraction (ED), high-angle annular dark field scanning TEM (HAADF–STEM), energy-filtered TEM (EF–TEM) and optical absorption spectro- scopy. Finally, the photocatalytic performances of selected samples in the decomposition of the azo-dye Plasmocorinth B are preliminarily investigated. The obtained results highlight the possibility of tailoring the system characteristics over a broad range, directly influencing their eventual functional properties.