Heterogeneous Doping Modification And Photocatalytic Properties Of Titanium Dioxide

In recent years, semiconductor photocatalytic materials exhibit an ideal way of providing efficient, clean and regenerated resource and efficient environmental treatment. As one kind of photocatalysts, TiO₂ has been widely used for high photocatalytic activity, thoroughly photodegradation organics and chemical stability without secondary pollution. However, there are some problems during the practical chemical industrial application and promotion of TiO₂, owing to relatively wide band gap and narrow range of photoresponse （λ<387 nm）. In this dissertation, our main ideas are synthesizing, characterizing, and calculating the crystal structure and photocatalytic performance of TiO₂-based photocatalytic materials. The main points could be summarized as follows:Firstly, we synthesized TiO₂ by hydrothermal synthesis crystallization method and characterized their phase structures, surface property through Transmission Electron Microscopy （TEM）, Field Emission Scanning Electron Microscopy （SEM）, X-ray diffraction （XRD）, X-ray Photoelectron Spectroscopy （XPS）. Brookite and Anatase prepared as hydrothermal time and temperature increasing from 1 h to 24 h and from 353.15 K to 453.15 k, respectively, and the crystallite size of samples increased with hydrothermal time and temperature. At the same time, based on homemade TiO₂ and commercial Degussa P25, samples prepared by impregnation and calcination method and characterized by SEM, TEM, XPS, UV-Vis, Raman, getting to know the crystallite size of CuO and Fe₂O₃ is 5-10 nm, element composition and valence state is Cu⁺², Fe⁺³, O^-2, Ti⁺⁴ and discovering CuO, Fe₂O₃.The photocatalytic hydrogen production and degradation of methyl orange （MO） experiments were performed to test samples photocatalytic activity and contrastive analyzed photocatalytic activity of degradation MO reaction of samples （2CT,2FT,2CFT, CT2, FT2, CFT2, CP2, FP2 and CFP2 prepared by the different preparation and modification methods） under ultraviolet, visible light irradiation. It is concluded that both ultraviolet and visible light illumination, the photocatalytic activity of samples （CFT2/CFT2/CFP2） is superior to CT2/2CT, FT2/2FT and P25, and the photocatalytic activity of samples （CT2/FT2/CFT2） prepared by leaching method is stronger than that of CP2/FP2/CFP, in turn, is better than that of hydrothermal synthesized samples （2CT/2FT/2CFT） for PN heterojunction expanding the titanium dioxide photoresponse range and promoting effective separation of the photogenerated electrons and holes （e^--h⁺）.Finally, based on the analysis of the reaction mechanism of photocatalytic water splitting and MO degradation of heterogeneous doping modification TiO₂, the photoelectric property of copper/iron codoped anatase titanium dioxide was investigated using quantum chemical principle （Density Functional Theory, DFT）, showing that the synergistic effect of Cu and Fe co-doping anatase TiO₂ according to the properties of electronic and optical results in the modification TiO₂ complex, indirectly proofing PN heterojunction contribution photoproduction e--h+the of separation from quantum chemical theory.