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

摘要

Developing a low-energy, efficient water treatment technology is a critical need. We fabricated nano-TiO_2 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 TiO_2 (Ag-TiO_2) and unmodified nanoparticle TiO_2 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-TiO_2 film than with the unmodified TiO_2 film. A control showed negligible degradation of MO in the absence of a TiO_2 film. The catalytic activity of the TiO_2 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-TiO_2 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-TiO_2 films to efficiently treat dissolved organic contaminants in water in the presence of sunlight.