Effect of metal-ion doping and noble metal deposition on photocatalytic activity of TiO₂

TiO₂ photocatalyst which was doped with La³⁺ and deposited Pt was prepared by using sol-gel-immersion method. Its degradation effect on direct fast blue was investigated. The results demonstrated that degradation effect of La³⁺/Pt/TiO₂ with TiO₂ dry gel as motherbody,after La³⁺,Pt⁴⁺ was in turn immersed,was 80% higher than that of TiO₂,36% higher than that of La³⁺/TiO₂ and 10.9% higher than that of Pt/TiO₂.XRD analysis indicated that anatase phase in TiO₂ was more than 95%,no oxidation phase of La³⁺,Pt was deposited on the surface of La³⁺/TiO₂,which was namometer-order atom. The mean crystal diameter was 7nm.FTIR analysis indicated that metal-ion doping and noble metal depositon could not greatly change the chemical structure of TiO₂.Photocatalytic activity was promoted because of electron-tractor effect of La³⁺ and redistribution of photogenerated carriers. The deposition of noble metal was favorate to separate electron-hole pairs,but the effect of degradation was worse for higher deposition.