Controlled Synthesis, Structures And Properties Of Metal Sulfide Nanomaterials

Now, much attention has been focused on metal sulfide semiconductor nanomaterialsdue to their unique physical and chemical properties and broad potential applications.The chemical composition and microstructure of the materials determines theirphysical and chemical properties, and the properties of materials have been reflectedin their practical applications. Innovative nanomaterials synthesized on a large scalewith controlled morphology, size, composition and structure lie at the heart of theirpractical applications. To achieve this, conventional solid-state and gaseous-statestrategies have many shortcomings, such as they always require complicated steps,drastic conditions and high-cost. So they are often unsatisfactory. Comparatively,liquid-based synthetic routes do not involve the use of drastic conditions (e.g., hightemperatures, high pressures) and yield products in large amounts. Additionally,liquid-based methods have been witnessed to be very powerful for obtaining desiredfunctional nanomaterials. The solvothermal method is a common liquid-basedsynthesis method. The hydrothermal method is a special case of the solvothermalapproach that uses water as the solvent, and the other solvothermal methords useorganic solvent. In these solvothermal synthesis, organic surfactants are always usedas templates or structure directing agents, which control the growth of themicrostructure and morphologies of the products. However, in most cases, the pureproduct was obtained only after the complete removal of the surfactants, which makesthe experiments become more complicated.Therefore, we wanted to study a new synthesis route, that is used solvothermalsynthesis method, without adding surfactant or other morphology directing agent. Byadjusting the reaction parameters in the solvothermal synthesis, for example, the kindand concentration of the raw materials, reaction temperature and reaction time, some metal sulfide with different the microstructure and morphologies could be controlledsynthesized.In this paper，some kinds metal sulfide of have been successfully synthesized by afacile solvothermal method without any surfactant assistance. The microstructure,morphologies and size of the products could be controlled by simple adjustments ofthe the reaction parameters. So their physical and chemical properties can be changed,thereby expanding application fields. This paper includes the following content：High quality self-assembled ZnS mesoporous nanospheres have been successfullysynthesized by a facile solvothermal method. The sample was synthesized usingethylene glycol aqueous solution without any surfactant assistance. It is a low cost,self-assembly of the synthetic route. We have discussed the influence of thetemperature, the concentration of reactants and the type of the sulfur source on thestructure of the products and established the formation mechanism. Size (50nm to2μm) and shape control of the ZnS mesoporous nanospheres is achieved by simpleadjustments of the concentration of the reactants. Investigation results show that ZnSspheres are made up of small ZnS nanocrystallites and show good photocatalyticactivity in the degradation of MB under the irradiation of ultraviolet light because oftheir mesoporous structures.High quality self-assembled erythrocyte-like CuS hierarchical nanostructures havebeen successfully synthesized by a facile solvothermal method. The sample wassynthesized using Dimethyl Sulfoxide as solvent without any surfactant assistance.Investigation results show that the erythrocyte-like CuS structures are constructed bymany two-dimensional circular nanosheets with the thickness of about50nm. Theother CuS structures (disk-like, rose-like) could be obtained through simply changingthe reaction condition (reaction time and temperature). The possible formationmechanism of the hierarchical nanostructures was oriented attachment growth andOstwald ripening mechanism. In addition, we also explored the acetate and halogenion play important roles in the reaction system.High quality self-assembled CdS hierarchical nanostructure materials have beensuccessfully synthesized by a facile solvothermal method. We use DMSO as solvent without adding any organic surfactants as structure-directing agent. The morphologyand structure of the products could be changed through simply changing theconcentration of raw materials and the amount of NaCl added. This synthetic routewhich need low temperature, short time, low cost, simple operation, is aself-assembed synthetic routes. All of CdS hierarchical nanostructures are made withsmall CdS nanocrystallites and they have high surface area. We also find that thechloridion can alter the aggregation mode of the nanocrystallites. Therefore, wecontrolled synthesized a series of CdS with different particle size, morphology and theband gap by this new synthesis system.This chapter we synthesized the copper sulfide microspheres and tubes by a simplehydrothermal methord. The microspheres and the tubes are composed of a largenumber of small nanoparticles, and they are self-assembled hierarchicalnanostructures. The method using polyethylene glycol as the structure-directing agentis a low-cost, self-assembled synthetic route. We also discussed the influence of theconcentration of the reactants, the chloride ions and indium ions on the morphologyand structure of the product. The diameter of the product of CuS ball (600nm to3μm)can be controlled by simply changing the concentration of the reactants. In addition,we synthesized the tube-like CuInS2and their structure were characterized by sometests. We had discussed the influence of the temperature and the time on the structureof products.