Synthesis Of Nanostructured ZnS And ZnSSe And Their Photocatalytic Activities

Ⅱ-Ⅵ nano-semiconductor materials have attracted considerable attentions owing to their novel physical and chemical properties and potential applications in many fields. In this paper, S-doped ZnS and ZnSSe nanoparticles have been successfully synthesized by a chemical solution-state reaction. Their structure, morphology, optical properties and photocatalytic activity were studied in detail. Compared with other methods, solution-state method has many prominent advantages:mild condition, easy to control, low cost and high production. So this large scale synthesis of ZnS and ZnSSe nanoparticals is more applicable to industrial production, which is promising for their broad applications in future.The main results are as follows:(1) Visible light-responsive S-doped ZnS photocatalysts have been successfully synthesized via using simple solution-state method. The XRD results confirm the formation of well-crystallized S-doped ZnS with zinc blende structure, and the diffraction peaks of the whole XRD patterns slightly shifted to the lower angles with the increasing S/Zn atomic ratio in the synthesis solutions, suggesting that the introduction of S in ZnS nanocrystalline. ICP-AES results reveal that S/Zn molar ratios can controlled by the content of reactants. The UV-Vis absorption results show the S dopant in ZnS nanoparticles could successfully extend its absorption to visible light region, meanwhile, the PL property decreased with increasing content of sulfur. In addition, visible light induced photocatalytic activities on the degradation of eosin B were investigated. It is found that the synthesized S-doped ZnS photocatalysts exhibited attractive activity under visible light irradiation.(2) Using TAA as sulfur source and Na2SeSO3as Se source, a new series of ternary ZnSxSel-x (0≤x≤1) nanoparticles were synthesized successfully by solution-state method at reflux temperature. The XRD diffraction peaks gradually shift to lower angles from ZnS to ZnSe with the increase of Se/S molar ratios. XRD results indicate ternary ZnSSe nanoparticles are alloy, but not a simple mixture of two compounds. The effects of composition x on the structure, lattice parameters and UV-Vis absorption properties were investigated. The results showed that the band gap can be tuned effectively by the composition x. Furthermore, the lattice parameters calculated from XRD dates decrease linearly with the increasing of composition x, which is consistent with Vegard’s law. The second-order polynomial function have been established between the bandgap energy (Eg) and the composition x of the ternary ZnSSe system. Finally, we also evaluated the influence of composition x on the photocatalytic activity of ZnSxSel-x under light irradiation. The results shows that, compared with pure ZnS and ZnSe, the synthesized ternary ZnSSe nanoparticles performed obviously enhanced photocatalytic activity for MB aqueous solution. The resulting alloyed ZnSSe samples are very promising photocatalysts for degrading other organic pollutants. This method provides a new choice for the synthesis of other multiple compounds.