The Morphology Control And Property Study Of Transition Metal Sulfides, Metal Oxide Nanomaterials

The morphology, size and structure of inorganic nanostructures play an important role in their properties. It is critical to effectively control these factors in order to fabricate many kinds of morphologies, which is also the aim of our experiment. Among the fabricating methods, hydrothermal method is one of the most attractive fields in chemistry and material science with the advantage of environmental-friendly method, well discreted and crystalline nanoparticles. Therefore, hydrothermal method was applied in our experiment.Herein, different experimental routes and reaction conditions in hydrothermal method were investigated, by which various inorganic functional materials with different morphologies were synthesized. By changing the ratio of reactants, temperature and time during the synthesis process, we successfully synthesized a series of novel nanostructures/sub-micron structures of metal oxide and metal sulfide, such as well-ordered ZnO nanostructure films, dendrite patterns of Fe₃O₄, flower-like CoS nanostructures and CoS nanocubes. At the same time, new route to synthesize some functional materials was established.1. Two typical structures (flower-like and cubes with surfaces hollowed out) were fabricated without surfactants by a hydrothermal method. The electrochemical measurements (CV) were carried out. The results indicated the capacitance of flower-like structure was higher than the one of cubes, which was caused by the higher specific surface area of the flower-like structure. In order to investigate the influence of the solution on the morphologies, different alcohols (methanol, glycol, n-propyl alcohol and n-butyl alcohol) were applied.2. A quick, simple, and scale-up hydrothermal synthetic method for preparing well-ordered ZnO nanostructure films with precisely the excess of the polar ZnO (0001) faces nano/microstructures was exploited. The as-prepared films were constructed of three kinds of nanostructures including porous nanosheet, nanotube and nanoflower, which could be realized by changing the alkali, reaction time and temperature. Among the three kinds of nanostructures, the porous ZnO nanosheets exhibit perfect photocatalytic activity by decomposing Rhodamine B under UV light irradiation. And the nanosheets are readily recovered for multiple uses. The main reason for the enhanced photocatalytic activity was the excess exposure of the polar ZnO (0001) faces which were the active sites for photocatalytic activity.3. A method for the growth and self-assembly of Fe₃O₄ nanoparticles that is template assisted, as well as gas diffusion and surface tension controlled, has been developed at room temperature. Well-defined dendrite patterns of Fe₃O₄ nanoparticles were obtained upon ion(Fe³⁺/Fe²⁺) entrapment in a polyethylene glycol solution followed by NH₃ gas exposure on the surface of an aqueous solution on the glass substrate. During the formation of Fe₃O₄ nanoparticles, the diffusion of volatile NH3 limits the hydrolysis rate of the molecular precursor and catalyzes slow formation. The template and surface tension also provided significant driving forces to promote the formation of dendrite patterns and in?uence the nature of the pattern. The Fe³⁺/Fe²⁺ concentration was varied in order to see the affects on the template molecular weight. SQUID measurements were used to characterize the final product. The derived patterned structure can be tailored by a simple combination of the physical and chemical procedure, which provides a new opportunity for obtaining a controllable pattern of nanoparticles.