Study Of The Oxide Semiconductor Materials: Microstructure Modulation And Property

In this thesis, we select zinc oxide and nickel oxide as the main objectives. Through the liquid phase synthesis method under different conditions to control the growth of oxide, nano ZnO and NiO particles with different morphologies were prepared, and then study the different morphology of nano oxide the impact of the performance.In addition, we can also learn from the surface of the load and the modification principles to increase ZnO and NiO light response range of materials, to improve its photocatalytic activity.The amplification of photoresponse range and the separation of photogenerated charge were developed by means of microstructure modulation, such as including the regulation of hierarchical structure or crystal facets, and surface loading modification. The emphasis points are as follows:In the first chapter, we systematic introduced the development and categories of ordinary semiconductor materials, and the outstanding properties and simple preparation methods of nanomaterials. Then we summarized in zinc oxide (ZnO) and nickel oxide (NiO) as a template, and further analysis of the principles of the photocatalytic reaction process, basic mechanism and semiconductor photocatalysis. Finally, the signification of topic selection, train of thought and outline of the thesis were summarized.In chapter two, the different morphologies were prepared by a simple liquid phase process with different surface modification agents in ethanol, such as ZnO tetradecahedral, wurtzite ZnO nanosheets and ZnO microspheres. The feasible reaction mechanism between ZnO and TMAH was put forward based on our experimental data. The produced samples were characterized by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Brunauer Emmett Teller (BET) surface areas and fourier transform infrared spectroscopy (FT-IR). Methylene blue (MB) was picked to test their photocatalytic activity under UV-visible light under ambient conditions,In chapter three, we introduced a simple, low cost and environmentally friendly solvothermal synthesis to form NiO microspheres with hierarchical structure by secondary crystallization. We synthesize ideas:Firstly, The initial precursor M3 (NO3) 2(OH) 4 nanoparticles were synthesized through the solvothermal process with urea; and then annealed, we can get different morphologies of hierarchical NiO microspheres. Due to their high surface area and open porous networks sructures, the NiO flower-like microspheres exhibit superior photocatalytic activity. Their porous structure has a high thermal stability. In view of morphology-evolution observation and characterization results, the formation process was abide by the dissolution-recrystallization mechanism.In chapter four, chemical bath deposition has been effectively used for the deposition of ZnO hexagonal nanosheets with the appropriate amount of hydrazine hydrate. Hereafter, ZnO/Ag heterostructures were prepared by photochemical synthesis in silver nitrate solution after the ultrasonic procedure. The ZnO/Ag composite particles were characterized by means of XRD, SEM (with EDS) and TEM. MB was elected to evaluate their photocatalytic activity and physical recyclability under visible light.In chapter five, we summarized our catena work and discussed the problems remained to be solved during graduate. Ultimately, we made a plan to solve the problem and looked forward to the future.In short, the photocatalytic properties can be greatly influenced by the particular microstructure of oxide semiconductor. In this thesis, we have obtained much growth regularity of the oxide particles. Photocatalytic performance was improved through microstructure modulation and surface loading modification. It is great theoretical guiding significance for expanding practical application of oxide semiconductor nanomaterials.