The Synthesis Of Metal Sulfides Nanocomposites And Their Photocatalysis Properties

Metal sulfides nanomaterials have attracted much attention with great potentials in cells, sensor materials, photocatalysis and so on. In a single component semiconductor, electron is restricted to the nanometre scale, and the separation of charge carrier is not efficient. In contrast, the combination of two or more semiconductors with different energy band would provide a potential gradient at the interface, promoting kinetic charge separation. The composition and morphology of nanomaterials is very important for the properties of nanomaterials, so the synthesis methods of nanomaterials is one of the important tasks for the researchers. In the last decades, great progresses have been achieved in colloidal synthesis of metallic and chalcogenide nanomaterials. In this thesis, we choose oleylamine, oleic acid, dodecanethiol as solvent. Different chalcogenide nanomaterials have been successfully synthesized through a fast and facile method, and their photocatalytic properties have also been studied. The main contents are as follow:1. we synthesize Cu1.94S/ZnS nanocomposites by using Cul and Zn(S2CNEt2)2 as precursors in oleylamine. The Au/Cu1.94S/ZnS nanocomposites were synthesized by loading Au nanoparticles with a size about 10 nm on the surface of the Cu1.94S/ZnS. The structure and morphology of the as-synthesized samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), Ultraviolet-Visible-Near-Infrared Spectrophotometer (UV-Vis). The photocatalytic activity of the as-synthesized samples was evaluated by monitoring the degradation of Rhodamine B (RhB) solution. The result showed that Au/Cu1.94S/ZnS nanocomposites revealed much higher photocatalytic activity than the Cu1.94S/ZnS. In addition,the possible mechanism for the enhanced photocatalytic properties of the Au/Cu1.94S/ZnS composite was also discussed.2. we synthesize graphene-like Co3S4 nanosheet/Ag2S nanocomposite from thermal co-decomposition of Ag(S2CNEt2) and Co(NO3)2·6H2O precursors in oleylamine and dodecanethiol. This is much more convenient than previously reported seeded growth or catalyst-assisted growth methods. The structure and morphology of the as-synthesized samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), Ultraviolet-Visible-Near-Infrared Spectrophotometer (UV-Vis). The photocatalytic activity of the as-synthesized samples was evaluated by monitoring the degradation of Methylene blue (MB) and Methyl orange (MO) under visible light irradiation. The result showed that Co3S4/Ag2S nanocomposites revealed much higher photocatalytic activity than the pure Co3S4 and Ag2S. This is attributed to the enhancement in the separation efficiency of electrons from holes because of the unique nanocomposite structure. In addition, the possible mechanism for the enhanced photocatalytic properties of the Co3S4/Ag2S nanocomposites was also discussed.3. we synthesize Ag2S/ZnS nanocomposites by using Ag(S2CNEt2) and Zn(S2CNEt2)2 as precursors in oleylamine and oleic acid. The structure and morphology of the as-synthesized samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), Ultraviolet-Visible-Near-Infrared Spectrophotometer (UV-Vis). The photocatalytic activity of the as-synthesized samples was evaluated by monitoring the degradation of Rhodamine B (RhB) solution. The result showed that Ag2S/ZnS nanocomposites revealed much high photocatalytic activity. We find that the solvent affects the structure and morphology of the Ag2S/ZnS nanocomposites. We also discussed the possible mechanism for the enhanced photocatalytic properties of the Ag2S/ZnS nanocomposites.