Preparation Of MoS₂ And Its Intercalation Compound And Their Performance Study

Layered materials such as MoS₂ nanocrystals have attracted much attention because of their superior mechanical properties and unique electronic behavior. These compounds the repeating motif in MoS₂ is a sandwich of the adjacent sulfur sheets together by Vander Waals bond. In this paper, MoS₂ is the main topic with respect to the synthesis of its intercalation compound, the properties of its electrochemistry, and its application for photocatalysis. Two chapters are dedicated to the application of ionic liquids in preparation of micro/nanomaterials, which can offer new ways of preparation of function materials. The details are summarized as follows.1. Hollow MoS₂ microspheres were synthesized in ionic liquids (1-butyl-3-methylimidazolium chloride, [BMIM]Cl)/water binary emulsions by the hydrothermal method using sodium molybdate and thiourea as starting materials. The structure and morphology of products were characterized by means of X-ray powder diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscopy (TEM). After a series of experiments, the optimum parameters of experiment are obtained as follows: the value of volumetric proportions (ILs/water) equaled 1:9, the reaction temperature is 180℃, and the reaction time is 24 h. The experimental results gave the evidences that the sample is consists of hollow spheres 1.8～2.1μm in diameter, and there are much sheet-like structures on the surface of hollow MoS₂ microspheres. ILs could be collected and reused for subsequent reactions. In addition, the reaction mechanism responsible for the formation of hollow spheres is explained, and the properties of its electrochemistry are tested.2. MoS₂ nanospheres and nanoflowers were synthesized by the hydrothermal method using PVP (K30),sodium molybdate and thiourea as raw materials. The structure, morphology and constituent of products were characterized by means of X-ray powder diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM), IR Spectrometry and thermogravimetry (TG-DTG). The experimental results gave the evidences that MoS₂ nanospheres were synthesized at 180 and 190℃; MoS₂ nanoflowers was synthesized at 200℃; the value of x is 4.74× 10^-3～7.97×10^-3 investigated initially. It can be speculated that the arrangement of PVP in MoS₂ layer is a molecular chain. In addition, the properties of its electrochemistry are tested too.3. MoS₂ nanoflowers were synthesized by the hydrothermal method using sodium molybdate, S powders and ethylene glycol as raw materials. The structure and morphology of products were characterized by means of X-ray powder diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscopy (TEM). The results indicated that many nanosheets are composed of the molybdenum disulfide nanoflowers with a controllable and tunable size between 200 and 500 nm. It is predicted that the effects of a considerable volume of ethylene glycol and high temperature during the hydrothermal process play an important role in the formation of MoS₂ nanoflowers. The cost of this method is cheap and economical. In addition, the properties of its electrochemistry are improved slightly.4. ZnO nanoparticles has been synthesized in ionic liquids (1-butyl-3-methylimidazolium chloride, [BMIM]Cl) by one-step solid-state reaction at room temperature at first. The structure and morphology of products were characterized by means of X-ray powder diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscopy (TEM). The results indicated that the average size of ZnO nanoparticles is 15 nm in diameter. Then the physical modification of the ZnO nanoparticles is performed by adding MoS₂ nanoflowers prepared in chapter 4. Finally, the photocatalytic property of the physically-modified ZnO (MoS₂@ZnO) was improved in photo-oxidative removal of rhodamine B solution.