Silver deposited titanium dioxide thin film for photocatalysis of organic compounds using natural light

Abstract

Developing a low-energy, efficient water treatment technology is a critical need. We fabricated nano-TiO2 coated films on glass substrates using the doctor-blade procedure and modified the film surfaces with silver (Ag). The films were characterized by X-ray diffraction, high resolution transmission electron microscopy and scanning electron microscopy with energy dispersive spectrometry. We compared the catalytic activity of silver modified nanoparticle TiO2 (Ag–TiO2) and unmodified nanoparticle TiO2 thin films towards photo-degradation of methyl orange (MO) under illumination of natural sunlight. When using the films for the first time, the degradation rate of MO was ∼18% greater in the presence of the Ag–TiO2 film than with the unmodified TiO2 film. A control showed negligible degradation of MO in the absence of a TiO2 film. The catalytic activity of the TiO2 films and their ability to degrade MO in batch experiments did not change significantly with repeated experiments. There was weak evidence that the degradation efficiency of the Ag–TiO2 films did decrease with repeated uses, but the decrease was small. This study demonstrates the potential of a novel application of silver modified and unmodified nano-TiO2 films to efficiently treat dissolved organic contaminants in water in the presence of sunlight.