Synthesis And Properties Of Metal Oxides And Metal Sulfides One-dimensional Nanomaterials

With the development and advanced research in nanoscience and nanotechnology, one-dimensional(1-D) nanomaterials have attracted intensive interesting due to their unique properties and widely application. Therefore, it is important to synthesize one-dimensional nanomaterials of different morphology and it is also significant to research their related properities.The aim of this thesis is to prepare one-dimensional structureλ-MnO2,γ-Mn3O4, ZnO/ZnS and CuS one-dimensional nanomaterials by simple chemical solution route. A liquid system was developed to synthesize one-dimensional structureλ-MnO2 and y-Mn3O4 nanorods. ZnO/ZnS heterostructured nanorods have been prepared through a hydrothermal method. Hierarchical CuS superstructures have been synthesized via a simple hydrothermal route. The morphologies and structures of as-prepared nanomaterials are characterized in detail. A systematic investigation has been carried out to understand the factors influencing the phase composition and morphology, and their formation mechanisms are also discussed. The main contents of this thesis can be summarized as follows:Ⅰ,A dipolar binary liquid system had been developed to synthesize one-dimensional structureλ-MnO2 andγ-Mn3O4 nanorods and electrochemical properties of as-prepared nanomaterials are investigated. Different morphologies of the products are prepared using MnCl2 as reactant in a dipolar binary liquid (water/benzene) system. We can control the composition and morphology of products by adjusting the reaction solution temperature, concentration and reaction time. It proved that higher temperatures and pH values are in favor of the formation of MnO2 and lower ones are in favor of the formation of Mn3O4. Due to the channels and pores formed by the basic unit [MnO6] octahedron and/or [MnO4] tetragon of manganese oxides linked in different ways, the research of products'electrochemical properties have also been studied. Electrochemical study demonstrated that the discharge capacities of MnO2 nanorod and Mn3O4 nanorod displayed noticeable electrochemical hydrogen storage ability (120 mAh/g and 180 mAh/g) respectively.Ⅱ,One-dimensional ZnO/ZnS heterostructured nanorod are successfully obtained by a simple one-pot hydrothermal method, in which zinc foil and Na2S2O3 were used as zinc source and sulfur source. The optical properties and gas sensitivity of as-prepared nanomaterials are investigated. Different shapely ZnO, ZnO/ZnS and ZnS nanostructures can be controllably synthesized through adjusting the reaction parameters of this chemical reaction process. It should be a synchronous growth process of ZnO and ZnS in the heterostructured nanorods by comparison experiments. PL measurement at room temperature shows the green emission at around 523 nm and 576 nm. At the same time, the as-synthesized heterostructured nanorods exhibit high sensitivity to ethanol at relatively low temperature.Ⅲ,A novel "ion-tailoring" method has been designed to prepared one-dimensional hierarchical CuS superstructures using FeCl2,CuCl2,Na2S2O3·5H2O as reactanand. Electron microscopy, X-ray diffraction, and optical spectroscopy were used to characterize the products. In this reaction the FeS2 nuclei formed first. With the aging time, FeS2 nuclei reacted with copper ions to form CuS by the temperature-control. The optical properties of the products formed at different temperatures were investigated using UV-vis absorption spectroscopy. UV absorption spectra at room temperature shows the green emission at around 380 nm and 620 nm. This novel designed strategy may be used for the preparation of other sulfide nanocrystalline superstructures.