Preparation And Photocatalytic Property Of (Mⁿ⁺?M₂O_n)/TiO₂?n=3,4? Structured Hollow-Fiber Materials

In this paper, a dip-calcination method?thermal conversion? was employed to prepare a series of samples of trace metal ions?<0.010?at.?%? doping TiO₂ ? semiconductor coupling TiO₂ hollow fiber photocatalytic materials with multilevel structure of(Sn⁴⁺?SnO₂)/TiO₂ ?(Fe³⁺?Fe₂O₃)/TiO₂ ?(Ti⁴⁺?TiO₂)/SnO₂ and(Ti⁴⁺?TiO₂) /Fe₂O₃ on cotton flower?CF? as a template. Size, surface structure, light response range and light absorption intensity, and the photocatalysis activity of the prepared samples were characterized by XRD, SEM, TEM, UV-Vis techniques and MB solution decolorizing effect under 300 W Hg lamp or 500 W Xe lamp. Specific research and characterization results are divided into the following two components.1. TiO₂ and a series of(Sn⁴⁺?SnO₂)/TiO₂,?Fe3 +?Fe₂O₃? /TiO₂ hollow fiber materials were prepared by dip- calcination?thermal conversion?, target materials were named Sn⁴⁺/TiO₂-A-1⁵?SnO₂/TiO₂-1⁶?Fe³⁺/TiO₂-1⁵?Fe₂O₃/TiO₂-1⁶. All materials were characterized by above test, the results showed that: under ultraviolet light?the main wavelength is 365 nm of 300 W Hg?, the photocatalysis activity of target materials(Sn⁴⁺/TiO₂-A-1⁵, SnO₂/TiO₂-1⁶, Fe³⁺/TiO₂-1⁵) showed a trend of first increased and then decreased, the photocatalysis activity of samples Sn⁴⁺/TiO₂-A-3?0.030?at.?%?, Fe³⁺/TiO₂-2?0.020?at.?%? and SnO₂/TiO₂-3?7.5?at.?%? respectively is the best among them, their activity were nearly 2.7?1.4?1.8 times of pure TiO₂, and the activity of Fe₂O₃/TiO₂-1⁶ were significantly lower than pure TiO₂. In addition,the photocatalysis degradation of MB solution follows first-order kinetic behavior well on the samples.In this part, we also prepared a series of Sn⁴⁺/TiO₂–B,C hollow fiber materials with different distribution of Sn⁴⁺ to TiO₂ by other methods, according to the analysis of XRD, SEM, TEM, Uv-vis and degradation results of MB solution on the samples, we can get a conclusion: the distribution of Sn⁴⁺ in TiO₂ has a significant impact on the photocatalytic performance of materials. We infer that the main reason are doping depth of Sn⁴⁺ and numbers of active sites introduced by the Sn⁴⁺.2. a series of(Ti⁴⁺?TiO₂)/SnO₂ and(Ti⁴⁺?TiO₂)/Fe₂O₃ hollow fibers materials(named Ti⁴⁺/SnO₂-1⁵? TiO₂/SnO₂-1⁵ ? Ti⁴⁺/Fe₂O₃-1⁵ ? TiO₂/Fe₂O₃-1⁶) were prepared via dip-calcination?thermal conversion? method. Based on the analysis of XRD, SEM, Uv-vis and degradation results of MB solution on the samples, the conclusion as follows: Ti⁴⁺ and TiO₂ have a significant improvement effect to the photocatalytic activity of SnO₂ under 300 W Hg?dominant wavelength is 365 nm? lamp, the photocatalytic activity of Ti⁴⁺/SnO₂-1⁵ and TiO₂/SnO₂-1⁵ increased firstly and then decreased with the increase of Ti⁴⁺ doped amount or TiO₂ coupled amount, Ti⁴⁺/SnO₂-2 and TiO₂/SnO₂-3 have the best activity when Ti⁴⁺ ion doping and TiO₂ coupled amount respectively is 0.030?at.?% and 17.5?at.?%. Their photocatalytic rate respectively is 1.3 and 3.3 times of pure SnO₂. Under 500 W Xe lamp, Ti⁴⁺ ion doping has no impact on the performance of Fe₂O₃, but TiO₂ play a significant role in terms of TiO₂/Fe₂O₃ performance promotion, the photocatalytic ratio of MB on sample TiO₂/Fe₂O₃-4 which the content of TiO₂ is 17.5?at.?%, promoted approximately 17% compared with pure Fe₂O₃ under the condition of light reaction 15 minutes, which mainly ascribed the electron- hole composite difficult due to the formation of heterojunction. In addition, the photocatalysis degradation of MB solution on the samples of Ti⁴⁺/SnO₂-1⁵ and TiO₂/SnO₂-1⁵ follow first-order kinetic behavior well.