Surfactant System, The Controlled Synthesis Of Metal Sulfides And Nature Study

Metal sulfides have exhibited extensive applications in catalysis, photoelectricity, gas sensing, magnetics and batteries due to their unique physical properties. Preparing novel metal sulfides nanostructures and investigating their general formation mechanism may be a solution to the precise control of their sizes, dimensionalities and properties. In this dissertation, systematic explorations have been carried out on new synthetic strategies of metal sulfides with the assistant of surfactants, and their formation mechanisms and novel properties.Large-scale three-dimensional cadmium sulfide spheres composed of hexagon-based pyramids were synthesized through a facile solution-phase reaction from CdCl2, thioacetamide, and a polymer surfactant, where the polymer acted as both dispersant and coating agent. The reaction conditions influencing the synthesis of these 3D CdS nanostructures such as reaction temperature, reaction time, the concentration of the polymer, and the kinds of precursors used were investigated. The possible formation mechanism of the novel CdS spheres was proposed based on the above analysis. The research showed that the surfactant played an important role in the formation of these three-dimensional CdS crystals.A facile chemical route for the synthesis of flower-like cadmium sulfide composed of morning-glory nanostructures from CdCl2 and thiourea in the present of the Pluronic amphiphilic triblock copolymer P123 was developed, where the P123 acted as both dispersant and coating agent. The reaction conditions influencing the synthesis of these 3D CdS nanostructures such as reaction temperature, reaction time, the concentration of the triblock copolymer, and the molar ratio of precursors were investigated. The results showed that the morphology of the products was greatly changed with the increasing of temperature. The possible formation mechanism of these novel CdS nanoflowers was proposed based on the above analysis. The photocatalytic activity of CdS particles with different morphologies had been tested by the degradation of acid fuchsine under UV light, showing that the as-prepared morning-glory-like CdS nanostructure exhibited high photocatalytic activity for degradation of acid fuchsine.Rod-like CdS nanostructures have been fabricated in CTAB/AOT mixed solutions using CdCl2 and thioacetamide as precursors. The reaction conditions influencing the synthesis of CdS nanostructures such as reaction temperature, reaction time, the concentration of the polymer, and the kinds of precursors used were investigated. The detailed structure of the junction of the bipods confirmed that the bipods grew form the same crystal plane. The possible formation mechanism of these rod-like CdS was discussed based on above analysis. The formation of this rod-like CdS nanostructure was due to the double layer structure formed by CTAB and AOT. When the reagents changed to Cd(AcO)2 and thiourea, urchin-like CdS nanostructure could be obtained.Novel CdIn2S4 hollow sphere with small bipyramids aggregating on its surface had been successfully synthesized via a facile hydrothermal process without any template or surfactant. The reaction conditions influencing the synthesis of these CdIn2S4 hollow sphere structures such as reaction temperature, reaction time, and the kinds of solvent used were investigated. Furthermore, on the basis of a series of observation, phenomenological elucidation of a mechanism for the growth of the CdIn2S4 hollow spheres has been presented. The physical properties,such as UV-vis diffuse reflectance spectrum and photoluminesce properties, were also investigated.. Hollow sphere structure of NiS was synthesized by hydrothermal method in H2O and N, N-dimethylformamide mixed solution. It was found that the formation of NiS was dependent on several factors. For example the molar ratio of precursor and the molar ratio of H2O and DMF all played an important role on the final morphologies of NiS. An Ostwald ripening mechanism may attribute to the formation of such hollow sphere structure. NiO hollow spheres could be obtained by a thermal treatment of the NiS hollow spheres. The photodegradation results showed that the as-prepared hollow NiO nanostructure exhibited high photocatalytic activity.