Solution Synthesis And Properties Of ZnS Micro/Nano Structural Materials

In this thesis, several kinds of of zinc sulfide nanostructures, such as nanowires andnanorods, porous nanospheres and heterostructured microflowers were prepared viadiffenert methods at a mild temperature. Morphologies and microstructures of theas-synthesized products were characterized by X-ray diffraction, scanning electronmicroscope and high-resolution transmission electron microscope. Effect of growthparameters on the morphologies of the as-obtained ZnS nanostructures wereinvestigated, the growth mechanisms of several unique nanostructures were proposedand photoluiminescence, photocatalytic and wettability properties of severalnanostructures were also studied.Large scale ZnS nanostructures were successfully obtained by a facilesolvothermal method at a mild temperature. Meanwhile, the morphologies,microstructures and properties of the as-synthesized products were characterized byscanning electron microscopy (SEM), transmission electron microscopy (TEM),photoluminescence (PL) and water contact angle (CA) measurements. The resultsshowed that these nanostructures possess a single crystalline structure and grow alongthe [0001] direction. Possible formation mechanisms for the growth of the ZnSnanostructures were proposed based on the experimental results. PL spectra of theas-synthesized products presented strong yellow light emission peaks. Water contactangle data demonstrated that the ZnS nanorod arrays possessed an excellentsuperhydrophobic ability.Porous ZnS nanospheres were achieved via a facile one-pot hydrothermal routewith the PVP assistance of surfactant. The as-obtained porous nanospheres have auniform diameter of about300nm and are composed of small nanocrystals with aspecific surface area of47.43m~2/g. Through an inspection of the morphologies undervarious growth conditions, a possible growth mechanism for the porous ZnSnanospheres is proposed, which involves nuclei aggregation and Ostwald ripening. Thephotocatalytic activities are tested by the photodegradation of Methylene Blue (MB),Methyl orange (MO) and eosin B under UV light irradiation, with a comparison withother ZnS nanostructures. Finally, a recycle photocatalytic capability is also demonstrated by repeating the degradation experiment five times，the photocatalyticcapability of products are still well.ZnO/ZnS heterostructured microflowers were fabricated through a rapid and facilestrategy via microwave assisted in sulfidizing ZnO route. The as-obtained productpossesses an average diameter of about2μm and is composed of many thin nanosheets.Through a careful inspection under various growth conditions, the morphologies of theas-prepared hybrid structures could be controlled by tailoring the concentration of TAAsolution during the microwave irradiation, and a possible growth mechanism wasproposed. The photocatalytic experiments results by the photodegradation of eosin Bunder simulated sunlight irradiation revealed that the hybrid nanostructures possesssignificantly higher photocatalytic activity which is about triple than that of the originalZnO precursors. The optimal sulfidation concentration to realize the maximumphotocatalytic activity in the ZnO/ZnS hybrid structures are also proposed anddiscussed.