Photocatalytic and antibacterial activity of TiO₂and Au/TiO₂nanosystems

Abstract

This work focuses on the photocatalytic performances and antibacterial activity of TiO 2 and Au/TiO 2 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 TiO 2 matrix has a beneficial influence on the azo-dye photodegradation, whereas the antimicrobial activity of Au/TiO 2 films is retarded with respect to pure TiO 2 .

Correlation of the Catalytic Activity for Oxidation Taking Place on Various TiO2 Surfaces with Surface OH Groups and Surface Oxygen Vacancies

“…We note that when using other metal oxide supports with large band gaps (e.g., ZrO 2 , CeO 2 ), AuNPs also exhibit high activity. [4] It has been reported that the Au/TiO 2 photocatalysts have high activity for the oxidation of organic molecules, [25] but the role of the Au-NPs has not been correctly explained because the photocatalytic activity of the Au-NPs themselves under visible light has not been recognized. The results of the present study provide clues to understanding these issues better.…”

“…Au-NPs have also been doped on to TiO 2 photocatalysts to enhance their performance for photocatalytic oxidation of organic molecules, [23][24][25] but the role of the Au-NPs has not been correctly understood. The surface plasmon resonance effect of Au-NPs, which is responsible for the visible light absorption by the Au-NPs, has been recognized for years, and recently we have found that the Au-NPs themselves exhibit significant photocatalytic activity under visible light irradiation.…”

Antibacterial dyeing of polyamide using turmeric as a natural dye

“…Many methods have been reported, such as fluorocarbon repellent finish, chemical binding of heterocyclic N halamine functional group to polyamide, using plasma, or immobilization of antimicrobial metallic nanoparticles on textiles (TiO 2 , Ag, Cu, ZnO, etc.) [5][6][7][8][9][10][11][12][13][14].…”

Janus Nanostructures Based on Au−TiO2 Heterodimers and Their Photocatalytic Activity in the Oxidation of Methanol

“…The photocatalytic activity was demonstrated by the oxidation of acetaldehyde. Armelao et al (20) deposited nanosized gold particles onto a TiO 2 sol-gel surface by radio-frequency sputtering and evaluated the photocatalytic activity with the photodecomposition of an azo dye (plasmocorinth B). The deposition of metal nanoparticles (silver and gold) onto TiO 2 particle surfaces has also been achieved by the photoreduction of metal salt precursors (21).…”