Synthesis, Characterization And Photocatalytic Activity Of Flower-like Micropheres Of ZnO Nanosheet

In recent years, the methods of high efficiency, energy saving and convenient were used photocatalytic, which was attended in degradation, transformation, and the mineralization of environmental pollutants, and the materials of photocatalytic are faced with serious challenges, therefore, the development of efficient photocatalyst has become an important research subject. Presently, the study of semiconductor nanometer materials was much more in all photocatalytic materials, and this materials combined with the properties of nanometer material and semiconductor, and shows broad application prospects in photocatalytic fields. ZnO as one of important photocatalysts for its high efficient, non-toxic, low cost, and has great potential in management and protection of environmental. As we all known, the morphology of inorganic materials has important influence on its properties and application. So the preparation of ZnO nano materials that has special morphology, not only can improve its optical properties, but also can improve the photocatalytic performance. Now, a lot of nano ZnO of different morphology has been synthesized, for example, comb shape, ring, linear and spring shape has been synthesized. And there are many reports about nano ZnO build unit that self-assembly and photocatalytic performance, but seek the economy is simple, environment friendly way to controllable synthesis2D ZnO nanosheet and using2D nanosheet to assemble3D grading structure of function and structured is still challenging.In this paper, using the hydrothermal synthesis methods, ZnO micropheres by synthesized in no template and adjusting the parameters of reaction conditions. Besides, the characterization, the photocatalytic degradation performance and the formation mechanism of ZnO nanosheet in hydrothermal process by carrying. According above contents, mainly done the following works:1. By reference to the previous literatures about synthesis of nanometer ZnO, using the hydrothermal methods, and the3D ZnO micropheres of thickness of10-20nm by synthesized in no any template and adjusting the parameters of reaction conditions. The ZnO hierarchitecture was characterized by XRD FT-IR、TG、SEM、TEM and XPS. With the commercial ZnO nanoparticles and the nanometer ZnO with thickness of10-20nm as photocatalyst to degradate RhB. The experimental results show that, compared with the commercial ZnO nanoparticles, the ZnO hierarchitecture exhibited higher photocatalytic activity, which can be attributed to larger surface area and the special3D structural feature of nanosheets.2. We report the formation mechanism of Zn5(CO3)2(OH)6nanosheets in hydrothermal ZnCl2-CO(NH2)2reaction system and their thermo-chemistry transformation towards ZnO nanosheets. Based on careful SEM and TEM observations of the morphologies and structures of the formed Zn5(CO3)2(OH)6nanosheets and their responses to electron beam irradiation, a particle-rod-sheet stepwise self-assembly mechanism is proposed for their formation. In this mechanism, rod-like objects are assembled in1D direction from initially formed nanoparticles, and then they further assemble into2D nanosheets in a side-by-side way. During the thermo-chemistry transformation of Zn5(CO3)2(OH)6nanosheets into ZnO nanosheets, the morphology and dimension of the nanosheets can be maintained. This proposed mechanism, particularly the lD-to-2D self-assembly process, might also work for the formation of sheet-like (or film-like) structures of other matters.3. Through investigate the influence factors of the thickness, we find that the nanometer ZnO with different thickness can be obtained by adjusting the reaction temperature, reaction time and the molar ratio of reactants.