Preparation, Characterization Of Zinc Oxide And Its Composite

Zinc oxides have been considered as important materials to resolve the energy and environmental issues, because of their excellent optical, gas sensing, photocatalysis, piezoelectric and other properties. At the same time, Zinc oxides have more advantages compared with other materials, such as non-toxic, low-cost, and simple preparation. In this paper, ZnO and ZnO/In2O3 composite materials have been successful prepared by a solution method at low temperature on the basis of previous studies. We studied the factors on the preparation, and discussed its formation mechanism. This method has many advantages, such as the simple process, low equipment requirements, repeatable, large-scale preparation. Finally, the properties of zinc oxide and its composites were characterized and the results showed that the samples obtained have very excellent optical and gas sensing performances. This method is a very promising technology for zinc oxide and its composites. The main conclusions are as follows:First, we studied the influence of different factors on the morphology of zinc oxides prepared from zinc acetate dihydrate, ammonia and hexamethylenetetramine in aqueous solution at low temperature. 1) The products have changed with the increase of temperature. Zinc hydroxides have been prepared when the temperature was below 40℃. On the contrary, the product was zinc oxides when the temperature was higher than the critical value (40℃).2) The study has found that the addition of additives has an important influence on the morphology of zinc oxides. The products were heterogeneous in size and had reunion when not adding hexamethylenetetramine. While spindle-shaped zinc oxide nanostructures with an almost uniform size of 100nm in diameter and 100-200nm in length were obtained with adding additives. This was mainly due to limitations and induction on morphology of additives.3) Photoluminescence spectra (PL) of zinc oxides prepared at low temperature were studied. The results showed that zinc oxides prepared at low temperature including three light emitting regions:the ultraviolet region (380-400nm), blue zone (460-480nm), yellow zone (540-580nm), and its light-emitting principles were described in this paper. 4) Spindle-shaped zinc oxide nanostructures sensors appeared the advantage of high selectivity for Nitric oxide.Micro/nanostructured ZnO/In2O3 composites have been prepared in situ growth at the low-temperature basic on our previous study. Results showed that the hierarchically micro/nanostructures ZnO/In2O3 composites with spindle-shaped zinc oxide particles with 100-200nm in diameter and about 500nm in length and indium oxide particles with 20-50nm in diameter. The size of zinc oxide and indium oxide were uniform and unagglomerate, indium oxide particles uniformly distribute on the surface of zinc oxide particle. Comparing with the morphology of composites without additives, we found that the addition of additives has great influence on the morphology and composite state of indium oxide of composite materials. In the photoluminescence (PL) properties of composite materials research, we found that the doping of indium oxide has great influence on the photoluminescence of composite material, which a red shift (about 50nm) and lower intensity appeared at UV peak, the relative increasing intensity at blue area, in addition to, yellow luminescence zone disappeared. The results show that these phenomena mainly due to the incorporation of indium elements and heat treatment. The sensing property of Zinc oxide has a great advantage because of dipping of indium oxide.We try to prepare the zinc oxide and composite films at solution. The results showed that the homogeneity of sheet film is good:no reunion with high surface area and pore structure be good as support materials and functional materials. This method is a simple, low cost preparation process for industrial production.