The synthesis and kinetic growth of anisotropic silver particles loaded on TiO2 surface by photoelectrochemical reduction method

Silver nanorods with average diameters of 120–230 nm and aspect ratio of 1.7–5.0 were deposited on the surface of TiO2 films by photoelectrochemical reduction of Ag+ to Ag under UV light. The composite films prepared on soda-lime glass substrates were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and atomic force microscopy (AFM). The results show that the TiO2 film after UV irradiation in AgNO3 solution is composed of anatase phase TiO2 and metallic silver with face centered cubic structure. Other compounds cannot be found in the final films. The maximum deposition content of silver particles on the surface of TiO2 film was obtained with the AgNO3 concentration of 0.1 M. The kinetic growth rates of silver particles can be controlled by photocatalytic activity of TiO2 films. The studies suggest that the growth rates of silver particles increase with the enhancement of photocatalytic activity of TiO2 films. The maximum growth rate of silver particles loaded on TiO2 films can be up to 0.353 nm min−1 among samples 1#, 2# and 3#, while the corresponding apparent rate constant of TiO2 is 1.751 × 10−3 min−1.