Synthesis, Characterization And Properties Research Of Zinc Oxide And Its Composite

ZnO is a n-type semiconductor with a band gap of3.2eV. As is known thatZnO is widely employed in the textile, cosmetic, ceramic, and glass industries.However, due to some unstable factors appeared in the preparation processionand some defects from itself, the actual applications are limited. In order toovercome these shortages, introducing another materials into the ZnO andconsequently broadening the applications,which has attracted more attention.In this paper, ZnO and its composites were successfully synthesized, andthe analysis on the performance of ZnO and its composite showed thatcomposites exhibit more excellent properties when compared with the individualZnO. The detail process is as follows:(1) Synthesis, characterization and optical properties of ZnO microstructureUrchin-like ZnO nanostructures were successfully synthesized by a facilesolvothermal route. X-ray powder diffraction (XRD) and scanning electronmicroscopy (SEM) were used to characterize the as-obtained products. It wasinteresting to find that the morphologies of the as-obtained ZnO were highlydependent on the adjustment of solvent ratio, and an obvious shape evolution ofZnO nanocrystals could be observed by changing the solvent ratio. Then basedon some captured intermediates, the possible growth mechanism of theas-obtained urchin-like ZnO nanostructures was proposed. Furthermore, thephotoluminescence properties of the ZnO nanostructures prepared at differenttime were also investigated.(2) Synthesis, characterization and adsorption/photocatalytic performanceof ZnO/CdS flowers.ZnO/CdS composites with flower-like morphology were fabricated byhomogeneous precipitation process at room temperature. The materialscharacterization showed that the composites were composed of hexagonal ZnOflowers and cubic CdS nanoparticles, and CdS nanoparticles were assembled onthe surface of flower-like ZnO microstructures. The presence of CdS nanoparticles onto the surface of ZnO flowers resulted in a blue shift of thecharacteristic peak and the decreasing of the PL intensity when compared withthe individual ZnO. Furthermore, the adsorption or photocatalytic degradationexperiments indicated that the as-prepared ZnO/CdS composites exhibitedsuperior adsorption or photocatalytic degradation activity for some organic dyes,such as Methyl orange (MO), Rhodamine B(RhB), Safranine T and Methyleneblue (MB), which may be related to the modification of CdS nanoparticles.(3) Synthesis and adsorption performance of tubular ZnO/FeS compositesTubular ZnO/FeS nanocomposite was synthesized by a facile two-stepchemical route. The as-obtained composite was characterized by X-raydiffraction (XRD), energy dispersive X-ray spectroscopy (EDX), transmissionelectron microscopy (TEM) and field-emission scanning electron microscopy(FE-SEM). The results show that the as-obtained composite was composed ofhexagonal ZnO tubes and cubic FeS nanosheets, and FeS nanosheets grewepitaxially on the outside surface of ZnO tubular structures. Furthermore, theas-obtained ZnO/FeS tubes also exhibited superior photoluminescence, opticalproperties and absorption degradation activity for some organic dyes (Methyleneblue (MB), Rhodamine B(RhB), Pyronine B(PB) and Methyl orange (MO))when compared to the individual ZnO, which may be used in the environmentalissues.(4) Synthesis, characterization and optical properties of ZnO/ZnS compositeZnO/ZnS composites were successfully synthesized via a facile two-stephydrothermal route. The as-obtained products were characterized by means ofX-ray diffraction (XRD), field-emission scanning electron microscopy(FE-SEM), Transmission electron microscopy (TEM), room temperaturefluorescence spectra (FTR) and Uv-vis spectrophotometer (Uv-vis) respectively.The materials characterization showed that the composites were composed ofhexagonal ZnO needles and cubic ZnS nanoparticles, and ZnS nanoparticleswere assembled on the surface of ZnO microstructures. Finally, thephotoluminescence (PL) spectrum and UV-visible absorption spectra of ZnOprecursor and ZnO/ZnS composite were analysised, the results showed thatZnO/ZnS composites exhibit more excellent photoluminescence and ultravioletabsorption performance. (5) Synthesis, characterization and optical properties of ZnO nanostructureWell-dispersed flower-like ZnO microstructures were successfullysynthesized via a hydrothermal route under the synergism between cetyltrimethylammonium bromide and sodium dodecyl benzene sulfonate. The as-obtainedproducts were characterized by means of X-ray diffraction (XRD),field-emission scanning electron microscopy (FE-SEM) and room temperaturefluorescence spectra (FTR), respectively.At the same time, the effects of reactiontime and the ratio of CTAB and SDBS were studied. The results show that theas-prepared flower-like ZnO microstructures were pure hexagonal phase, thediameter was about2-3μm and the best ratio of CTAB and SDBS was4:1. Thephotoluminescence (PL) spectrum dates show that the as-synthesized ZnOflowers exhibit two emission peaks locating at the ultraviolet region and visibleregion respectively. With the increase of the reaction time, the fluorescenceintensity of the ultraviolet region reduced; while the fluorescence intensity of thevisible region reaches its maximum at the reaction time2h.