Synthesis And Photocatalytic Activity Of Novel Composite Photocatalysts

The energy crisis and environmental pollution problems are harmful to human survival and society development in many aspects. Governments are committed to the development of new energy and environmental governance, the application of semiconductor photocatalyst in this fields has attracted much attention. Many traditional photocatalysts such as TiO2 and ZnO have been widely used in the photocatalytic field due to their stability and optical property. However, some drawbacks of the catalyst greatly restrict their application in many fields, for example, the low quantum efficiency and narrow spectral response range(only excited by ultraviolet light), thus, the synthesis of novel photocatalysts with high efficiency is of great importance.To solve the problems mentioned above, we have finished the following works:(1) Coupling CdS with another wide band gap semiconductor to form heterostructure, thus, the charge separation efficiency of CdS is highly improved and the photocatalytic activity is highly improved.(2) synthesizing a series of novel photocatalyst with peculiar morphology. The main working are as follows:Chapter 1, the research progress of semiconductor photocatalysis and the principle of the photocatalysis was described in detail. Furthermore, several approaches to enhance the activity of photocatalysts were introduced.Chapter 2, self-assembly of TiO2/CdS mesoporous microspheres were synthesized via hydrothermal method. The samples were characterized by XRD?DRS?TEM?EDS?HRTEM?BET?XPS and PL. The as-synthesized TiO2/CdS mesoporous microspheres showed superior photocatalytic activity on the degradation of RhB under either visible light or simulatedsunlight irradiation. The heterojunction between TiO2 and CdS may be favorable for the transport of photoinduced electrons from CdS to TiO2. In addition, the mesoporous structure could increase the utilization of light energy and facilitate the difusion of reactants and products during the photocatalytic reaction. The synergistic effect of the various factors leads to the enhancement of photocatalytic activity of the as-synthesized TiO2/CdS mesoporous microspheres.Chapter 3, the morphology-controlled synthesis of Bi19Cl3S27 hollow nanotube was achieved via hydrothermal method. The samples were characterized by XRD?TEM?SEM?DRS?EDS?BET?PL. These nanotubes are tens of nanometer in width. There are many mesopores on the surface of the tube, which plays an important role in adsorption. The hollow Bi19Cl3S27 nanotubes exhibited excellent photocatalytic activity for the degradation of RhB under simulated sunlight irradiation. The enhanced photocatalytic activity can be attributed to the hollow tube structure and the mesopores dispersed on the surface and the large surface area induced by the special srtucture.Chapter 4, BiOBr mesoporous microspheres and BiSI nanorods were successfully synthesized in hydrothermal environment. The samples were characterized by XRD?TEM?SEM?DRS?EDS?BET?PL. These as-synthesized samples exhibited excellent photocatalytic activity for the degradation of RhB under simulated sunlight irradiation.Chapter 5, we summarized the conclusions in this thesis and forecasted the development direction of photocatalytic technology based on the research results and the current level of photocatalytic materials research.