Study On The Visible Light Antibacterial Activity Of Dopped Nano-photocatalysts

TiO₂ powder and film could purify circumstance due to their antibacterial action and photocatalytic degradation of organic polluted compounds under the radiation of UV. So TiO₂ photocatalyst has a variety of application prospects in the field of environmental protection.Ag/TiO₂, V/TiO₂ and La/TiO₂ powder photocatalysts with visible-light activities were prepared by sol-gel method. And, the so-prepared photocatalysts were characterized by XPS, XRD and UV-vis. XPS showed that Ag existed as metal, whereas La existed as oxide. The crystalline structure of Ag/TiO₂, V/TiO₂ or La/TiO₂ was all anastase, and doping V5+ ion in TiO₂ resulted in the peak shape of X-ray diffraction broadened. UV-vis absorbance spectra of Ag/TiO₂, V/TiO₂ or La/TiO₂ showed that absorption limits bathochromic shift occur in the doped photocatalysts. Moreover, the absorbance intensity of Ag/TiO₂, V/TiO₂ or La/TiO₂ was higher than that of pure TiO₂ under visible region.With black light lamp or fluorescent lamp as light source, the antibacterial experiments and photodegradation of methyl orange solution were carried out to investigate the visible-light activity of Ag/TiO₂, V/TiO₂ and La/TiO₂ powder. From the results, it could be found all the three kinds of photocatalysts took on good visible-light activity.In order to reduce the cost of TiO₂ powder, the inorganic salt was used as resource to prepare co-doped TiO₂ powder by the chemical precipitation and impregnating methods. The photocatalytic experiment results showed that the co-doped TiO₂ photocatalysts have good photocatalytic activity under visible light irradiation.Since film materials have more application prospects than powder, TiO₂ films were prepared in this study. The antibacterial properties and photodegradation of polluted organic compound were analyzed. By doping of rare earth element, the La/TiO₂ and Ce/TiO₂ film photocatalysts were prepared by sol-gel method. These La/TiO₂ or Ce/TiO₂ films can kill bacteria and degrade methyl orange under visible light irradiation.Perovskite type oxides are a new-style photocatalysts with visible-light activities. In our experiment, the LaCoO₃ and its multicomponent perovskite type oxides with uniform size were prepared by citric acid complex method. Simultaneity, the photocatalytic activity and antibacterial performance of the powders were analyzed. The results showed that the photocatalytic activity and antibacterial performance were decrease with the increase of the particle size and the decrease of Cu content. And, in LaBO₃ multicomponent perovskite type oxides, the trend of photocatalytic activity and antibacterial performance were LaCoO₃>LaFeO3>LaMnO3.