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Electrosynthesis and Performances of Nanosilver and Zinc Oxide/Zinc Sulfide

Author: ChangXiaoYing
Tutor: YuanGaoQing
School: South China University of Technology
Course: Physical and chemical
Keywords: Electrodeposition Nanosilver Surface-Modification Oleic acid ZnO/ZnS Composite materials
CLC: TB383.1
Type: Master's thesis
Year: 2011
Downloads: 112
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Abstract


Pure or composite nanomaterials have potential applications in many fields such as electricity, optics, sensors, catalysis and biological medicine because they have unique physical and chemical properties.Nano-metal Ag, as one of important metal materials, has attracted considerable interest recently due to their important applications in many fields such as electric and electronic industries, sensors, catalysis and antibacterial materials Thus, it is very critical to investigate on the shape–controlled synthesis of Ag nano-material. So far, various methods have been developed to prepare Ag nano-materials with different shapes and sizes. Among these synthetic methods, an electrochemical method appears to be attractive because of its simplicity, mild react conditions and without use of any reducing agent or expensive equipment. With H2O-oleic acid or H2O-glycerol （volume ratio 1:1） as electrolytic medium, AgNO3 as supporting electrolyte and sodium dodecyl sulfate （SDS） as additive, we demonstrated an efficient electrochemical route to realize the shape-controlled synthesis of Ag crystals. The SEM （scanning electron microscopy） results show that the shapes and sizes of Ag crystals are strongly dependent on electrolytic media, additive SDS and current density. At current density 10 mA/cm2, the sphere-like Ag nanoparticles could be obtained in the presence of SDS （0.6 g/L）, while the Ag sample electrodeposited without SDS has dendritic microcrystals structures. Also,the dendritic microcrystals structures could be obtained on the surface of H2O-oleic acid. With the reduction of methyl orange （MO） and methylene blue （MB） catalyzed by Ag nanocrystal as the model reaction, the relationship between the catalytic performances of the Ag crystals and their shapes and sizes were also examined. The investigations indicate that the dendritic Ag microcrystals electrodeposited in H2O-oleic acid mix-solvent exhibit more excellent catalytic performance, which is obviously superior to those of the sphere-like Ag nanocrystals and dendritic microcrystals prepared in the H2O-glycerol mix-solvent. The catalytic performances of the as-prepared Ag samples are not only dependent on their shapes and sizes but also closely related to their surface-modification.ZnO and ZnS are important semiconductor materials and have good photoluminescence and catalytic properties. In this paper, we prepared ZnO/ZnS composite nanomaterials via an electrochemical method by controlling electrolytic conditions. SEM, XRD （X-ray diffraction） and PL （photoluminescence） were used to characterize the morphology and structure of the products. The relationship between the photoluminescence property of ZnO/ZnS and their composition was also examined.

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