Study On The Preparation And Photocatalytic Properties Of Titanium Dioxide Nanocomposite Structures

Nano-Ti O₂ semiconductor in the field of photocatalysis has a high priority,due to its stable physical and chemical properties,non-toxic,low cost.However there are still some unavoidable problems in the actual operation process,such as the high recombination probability of electron-hole pairs generated by excitation,and the narrow light absoption range.In view of the above,this mainly based on the preparation of TiO₂ semiconductor materials by hydrothermal method.To improve the research of TiO₂ semiconductor materials,by turning the sizes and the use of up-down conversion of light-emitting element doping,and other semiconductor composite.The main contributions of the thesis include the following aspects:1.CdSe-sensitized TiO₂ nanorod arrays?CdSe/TiO₂ NRAs?grown on FTO coated with TiO₂:Yb³⁺,Er³⁺ thin film was constructed.The TiO₂:Yb³⁺,Er³⁺ thin film acted as a medium for converting NIR to visible light via upconversion process and reduced electron-hole recombination.TiO₂ NRAs with high specific surface areas,well-aligned nanostructures can provide a fast transfer pathway for photogenerated electrons.The CdSe / TiO₂ NRAs extended optical response from UV to visible region,which can generate more electron-hole pairs.The TiO₂ NRAs / TiO₂:Yb³⁺,Er³⁺ exhibited excellent photocatalytic activity toward the degration of Rhodamine B?RhB?.The composite structure can not only extend the absorption of TiO₂ but also consequently reduce electron-hole recombination,which improve the photocatalytic efficiency of the composite photocatalyst.2.In order to improve the catalytic performance of the nanostructured photocatalysts,TiO₂ NRAs:Eu³⁺,Tb³⁺ decorated with Cs2CO3/CdS grown on carbon textiles coated with a TiO₂-G thin film(TiO₂-G/TiO₂ NRAs:Eu³⁺,Tb³⁺/Cs2CO3/CdS)was fabricated.Rhodamine B as a model pollutant was used to investigate the photocatalytic activity of Ti O₂-G/TiO₂ NRAs:Eu³⁺,Tb³⁺/Cs2CO3/CdS.It is found that the composite photocatalyst TiO₂-G/TiO₂ NRAs:Eu³⁺,Tb³⁺/Cs2CO3/CdS exhibits markedly enhanced photocatalytic performance.Such great enhancement in the photocatalytic activity indicates that the presence of Eu³⁺,Tb³⁺ can be excited by UV light to produce a high intensity visibe light absorbed by CdS,which can generate more photogenerated electron hole pairs.In addition,the presence of graphene and Cs2CO3 layer is the important factor in accelerating the transferring of photogenerated electron to carbon textiles for photocatalytic reaction.Moreover,the photocatalyst grown on carbon textiles directly makes it possible to collect and recycle.3.The CH3NH3 Pb I3 acted as the main solar light absorber?350nm<?<800nm?plays a crucial role in the better photocatalytic performance.The TiO₂ nanorod arrays?NRAs?filled with CH3NH3PbI3 were coated by Cu2 O,which was fabricated on the carbon fiber to form photocatalyst TiO₂ NRAs/CH3NH3PbI3/Cu2 O.The difference of the energy level in the Ti O₂ NRAs/CH3NH3 Pb I3/Cu2 O makes a positive contribution to the effective separation of the photogenerated carries.The composite structure photocatalyst TiO₂ NRAs/CH3NH3PbI3/Cu2 O has been prepared,which exhibits superior photocatalytic performance.4.The application of Ti O₂ nanosheet arrays?Ti O₂ NSAs?with larger specific surface area in photocatalytic degradation is rarely reported.Especially,TiO₂ nanosheet arrays grown on the carbon cloth can construct three dimensional?3D?structures to improve the specific surface area.In this study,the composite structure of TiO₂ NSAs/Cu2 O has been prepared.The morphological,structural and photocatalytic properties of the as-synthesized products were characterized.