The Preparation And Study Performance Of TiO₂ Complexed By Metal And Semiconductor Nano-particles

Study on the photocatalytic activity and photoinduced hydrophilicity of TiO₂ thin films and powders, which were complexed with metal and semiconductor nanoparticles.(1) The composite TiO₂ thin films were synthesized on the clean glass, using sol-gel and soak-lifting method and were characterized by SEM. Photo-induced hydrophilicity was studied by measuring the contact angle of composite TiO₂ thin films, using contact angle system. Under the protection of PVP, TiO₂ nanoparticles became small. When the annealing point reached 400℃, the spherical TiO₂ nanoparticles distributed equably. The hydrophilic degree of bi-layer thin films was as follows: TiO_2(top)/SiO_2(bottom)＞TiO₂＞SiO_2(top)/TiO_2(bottom)＞SiO₂. UV irradiation could improve the hydrophilicity of films.(2) TiO₂ composite films with different diameter of nano-Ag and TiO₂ powders with different content of Ag nanoparticles were synthesized by mixing sol and ultrasonic dispersion method, PVP used for protectors. Three nano-particle sizes of Ag were measured by TEM. Different content levels of Ag compouded TiO₂ powders were characterized by XRD. The photocurrent and photocatalytic activity of TiO₂ composite films with three different dimensions of nano-Ag were enhanced. When the particle size of Ag was 6.9 nm, the photocurrent and photocatalytic activity of the composite films reached the maximum. When the content level of nano-Ag compounded TiO₂ powders was 0.75ï¼…, the photodegradation efficiency of acetocaustin reached 73ï¼…, after UV-irradiation for 3 h.(3) Sol-gel method was used to prepare PVP protected TiO₂ and CdS nano-particles, which were characterized by UV-vis absorption spectra, TEM and SEM. UV-vis diffusing reflectance spectra and SEM have been used to investigate AOT protected CdS/TiO₂ composite nanopowders. Comparing with pure TiO₂ powders, 4.2ï¼…CdS compouding TiO₂ significantly increased the visible photocatalytic activity due to the higher response to visible light. After visible light illumination 4h, the photodegradation ratio of methyl blue reached 75.6ï¼…by sol-gel process and 87.5ï¼…with reverse micelle method.