Low-temperature Synthesis of Metallic Silver Particles Doped TiO₂ and its Photocatalytic Activity

Photocatalyst composite materials consisting of silver and titanium dioxide were synthesized at low temperature (70℃) by a modified sol-gel method using tetrabutyl titanate and homemade nanosilver solution. Homemade nanosilver solution was synthesized by using tannic acid as a protective agent.Characterization methods including scanning electron microscope, transmission electron microscope, and X-ray diffraction are employed to prove the existence of TiO₂. Moreover, X-ray photoelectron spectroscopy is employed to prove the existence of metallic silver Particles. Using methyl orange as simulated pollutant,the influence of content of Ag, Ag/TiO₂ and different initial concentration of methyl orange on photocatalytic activity of Ag/TiO₂ composite material were examined. The results shown that the photocatalytic activity of Ag/TiO₂ composite materials increases at first and then decreases with the increase of content of Ag as well as the amount of Ag/TiO₂. Finally, we get the best activity photocatalyst when the content of Ag is 0.18% and the amount of Ag/TiO₂ is 10mL. The photocatalytic activity of Ag/TiO₂ composite materials enhanced with the increase of initial concentration of methyl orange within the range of concentration that can be measured by uv-vis spectrophotometer.