Photocatalytic and antibacterial activity of TiO2 and Au/TiO2 nanosystems

This work focuses on the photocatalytic performances and antibacterial activity of TiO2 and Au/ TiO2 nanosystems. While the former are obtained by a sol - gel route, the latter are synthesized by an innovative hybrid RF- sputtering/ sol - gel approach, followed by ex situ annealing in air up to 600. C. Important information on nanoparticle size, shape and distribution is obtained by the combined use of glancing incidence x- ray diffraction ( GIXRD) and field emission- scanning electron microscopy ( FE- SEM). Subsequently, the photocatalytic performances of the obtained nanosystems in the decomposition of the azo- dye Plasmocorinth B and their antibacterial activity in the elimination of Bacillus subtilis are illustrated and discussed in comparison with films obtained from standard Degussa P25 powders. The obtained results show a significant dependence of the functional performances on the system's compositional, structural and morphological properties. In particular, the dispersion of gold nanoparticles on the TiO2 matrix has a beneficial influence on the azo- dye photodegradation, whereas the antimicrobial activity of Au/ TiO2 films is retarded with respect to pure TiO2.