Template Synthesis Of Ag/TiO₂, Ni²⁺/TiO₂, SnO₂/ZnO Hollow Nano-fibers And Research Of Their Photocatalytic Properties

In this thesis, Ag/TiO₂, Ni²⁺/TiO₂ and SnO₂/ZnO hollow nano-fiber photocatalytic materials were successfully synthesized by using cotton fiber as the template. The features of these photocatalytic materials, such as morphologies, phase structures, spectral response and so on were characterized by various techniques. Their photocatalytic properties were evaluated by using the degradation of dye methylene blue (MB) solution as model reaction. This thesis mainly consists of following three major aspects.1. A series of Ag-doped TiO₂ hollow nano-fiber photocatalytic materials were successfully prepared by using cotton fiber as the template and characterized by thermogravimetric analysis (TG), scanning electron microscopy (SEM), X-ray diffractometry (XRD), UV-Vis and IR measurement techniques. Using the degradation of methylene blue (MB) solution as the model reaction, the effect of light source, the catalyst amount, the amounts of Ag-doped, calcining temperature and calcining time on the photocatalytic activity of the Ag/TiO₂ nano-fiber material was investigated. The results showed that the sample showed much better photocatalytic property than pure TiO₂ and its activity was higher under the sunlight than under UV irradiation. On the surface of the nano-fiber material with 0.2 % Ag-doped which was treated at 620 oC for 2 h, the decolorizing efficiency of MB solution reached 100 % when radiation time was 3 h. The efficiency was kept above 90 % when it was repeatedly used for 5 times and the material was easily removed by centrifugal separation. Therefore, Ag/TiO₂ hollow nano-fiber material, synthesized by the template method, is no energy consumption, no pollution, good photocatalytic property and green environment-friendly catalytic material.2. A series of Ni²⁺-doped TiO₂ hollow nano-fiber photocatalytic materials were successfully prepared by using cotton fiber as the template and characterized by thermogravimetric analysis (TG), scanning electron microscopy (SEM), X-ray diffractometry (XRD), UV-Vis and IR measurement techniques. Using the degradation of methylene blue (MB) solution as the model reaction, the effect of light source, the catalyst amount, the amounts of Ni²⁺-doped, calcining temperature and calcining time on the photocatalytic activity of the Ni²⁺/TiO₂ nano-fiber material was investigated. The results showed that the hollow nano-fiber photocatalytic material with 0.05 % Ni²⁺-doped calcined at 650 oC for 2 h had the highest catalytic activity under solar light. Under optimal conditions, the degradation of MB reached 100 % by 4 h radiation time.3. A series of SnO₂/ZnO hollow nano-fiber photocatalytic materials were successfully prepared by using cotton fiber as the template and characterized by scanning electron microscopy (SEM), X-ray diffractometry (XRD), UV-Vis and IR measurement techniques. Using the degradation of methylene blue (MB) solution as the model reaction, the effect of light source, the amounts of SnO₂-doped and calcining temperature on the photocatalytic activity of the SnO₂/ZnO nano-fiber material was investigated. The results showed that SnO₂/ZnO hollow nano-fiber photocatalytic material with molar ration of 0.1:1 calcined at 650 oC could make the decolorizing efficiency of MB solution reached 100 % when radiation time was 1 h under solar light.