Modification And Photocatalytic Properties Of New Visible Light Driven Photocatalyst Bi₁₂TiO₂₀

In recent years, great advancement has been achieved in the research of photocatalytic technique. TiO2has been drawn much attention due to its non-toxicity, high catalytic activity, good oxidation performance and good chemical stability. It can only utilize ultraviolet light for its wide band gap, leading to the low utilization rate of sunlight. So, it is an urgent and important task to develop visible light driven photocatalyst to make better use of sunlight. B12Ti020has been paid much more attention due to its good photoconductivity and photocatalytic activity. Considering the good advantages, the author prepared various kinds of modified catalysts showing high photocatalytic performance under visible light through a simple method. The morphology and structure of the samples have been characterized using analytical techniques of XRD、UV-Vis、 SEM、XPS、BET. The relationship between the microstructure and photocatalytic properties was investigated. Some conclusions have been made as follows:1. Er3+doped Bi12TiO20photocatalysts were prepared. The low content dopant has no influence on the phase of Bi12TiO20but inhibits its growth. The low content Er3+dopant can extend the photoresponse range of Bi12TiO20which can show stronger absorption to visible light with the increase of Er3+content. Different Er3+dopant contents, calcianation temperature, calcination time on the influence of band structure and photocatalytic performance of Bi12TiO20were studied. The photocatalytic degradation of methyl orange showed that the Bi12TiO20photocatalyst of0.5%Er3+calcined at400℃for30min possesses the best catalytic activity, and the degradation rate of methyl orange reaches almost100%within3h under visible light (λ＞400nm).2. Pr3+doped Bi12TiO20photocatalysts were prepared. The results indicated that Pr3+dopant almost has no influence on the phase of Bi12TiO20.The Pr3+doped Bi12TiO20photocatalysts had red shift and showed stronger absorption to visible light with the increase content of Pr3+. The electron cloud distribution of Bi3+was influenced by the doping of Pr3+, and it can lower the binding energies of Bi4f and Ols of the modified photocatalysts. The photocatalytic degradation of methyl orange showed that the Bi12TiO20photocatalyst of1%Pr3+calcined at400℃for60min possesses the best catalytic activity under visible light (λ＞400nm).3. N doped Bi12TiO20photocatalysts were prepared with urea and Bi12TiO20. The Bi12TiO20absorption intensity increased and absorption edge had a little red shift when N was doped. Nitrogen atom can replace oxygen atom in the lattice, generating additional energy level and narrowing the bandgap width. As a result, the N doped Bi12TiO20photocatalyst showed stronger absorption intensity and wider absorption range. The photocatalytic degradation of methyl orange showed that the Bi12TiO20-y Ny(y=0.03) photocatalyst calcined at400℃for60min possesses the best catalytic activity under visible light (λ＞400nm).