Synthesis, Characterization And Properties Research Of ZnS Nanocomposites

ZnS is regarded as one of the typical Ⅱ-Ⅵ semiconductor materials with wide band gap energy of 3.6 e V. ZnS has attracted tremendous attention due to its superior properties and prominent applications in flat-panel displays, solar cells, infrared windows and sensors. Especially, ZnS can be also utilized as a photocatalyst for water treatment of organic pollutions. While, continuous research shows that the composite structures have aroused the increasing research interests due to their superior properties and promising application compared to the single-component counterparts. There is no doubt that it has huge potential for developing the composites with superior properties.In this paper, ZnS composites with superior properties have been successfully synthesized. The detailed studies of the thesis are as follows.ZnS/Ni2 P core/shell composites were synthesized successfully using the hydrothermal method. The composites were characterized and the corresponding results show that the composites are composed of the cubic ZnS microspheres, which are made up of ZnS nanoparticles, and Ni2 P nanoparticles coated on the surfaces of ZnS microspheres. And the photocatalytic activities of the obtained samples were evaluated by the photodegradation of model organic pollutants pyronine B dye, and the as-prepared ZnS/Ni2 P core/shell composites showed enhanced photocatalytic degradation activity for pyronine B under UV irradiation. This may be related to the effective separation of photoexcited electron-hole pairs for ZnS/Ni2 P composites which can greatly reduce the chance of their recombination. Furthermore, superoxide ions and hydroxyl radical can be produced more easier which are beneficial for the degradation of pyronine B.ZnS/Ni2 P composites were synthesized successfully via the hydrothermal route using as-prepared ZnS as raw material, nickel acetate as nickel source and white phosphorus as phosphorus source. The composites were characterized by XRD, SEM and TEM. The corresponding results show that the composites are composed of the cubic ZnS microspheres, which are made up of ZnS particles, and hexagonal Ni2 P particles attached to the surfaces of ZnS microspheres. Furthermore, the photocatalytic degradation experiments were carried out and the results indicated that the obtained ZnS/Ni2 P composites showed superior photocatalytic activity compared to the pure ZnS microspheres. Also, the photodegradation experiments for pyronine B with various concentrations of ZnS:Ni2P were implemented. It can be found that too big or too small concentrations of ZnS:Ni2P can exert negative influence on the photocatalytic activity.Magneto-luminescent ZnS/Fe3O4 composites were synthesized successfully by combining the hydrothermal and solvothermal method together. The composites are composed of the cubic ZnS microspheres, which are made up of ZnS particles, and Fe3O4 nanoparticles attached to the surfaces of ZnS microspheres. The photoluminescence(PL) spectroscopy of the ZnS/Fe3O4 composites suggests that the existence of Fe3O4 nanoparticles on the surface of ZnS microspheres could lead to fluorescence quenching effect to some degree, so that the fluorescence intensity of ZnS/Fe3O4 composites can be observed to decrease. While the red shift of the PL spectra of ZnS/Fe3O4 composites may be attributed to the shallow-trap radiative recombination facilitated by the Fe3O4 nanoparticles. Furthermore, the as-prepared ZnS/Fe3O4 microspheres exhibited the magnetic responses so that it can be separated from the solution with the assistance of the magnet force.