Preparation And Characterization Of Zinc Oxide Micro/Nanostructures By Low Temperature Aqueous Solution

Zinc oxide is a wide band gap semiconducting material with a direct wide band gap of3.37eV and a large exciton binding energy of60meV at room temperature. Due to its remarkable performance in photocatalytic, photovoltaic, piezoelectric, field emission, microwave absorbing, transport, dilute magnetic performances, ZnO nanomaterials are attractive candidates for many applications such as catalysis, optoelectronics, piezoelectric materials, field emission catalysis, optoelectronics, piezoelectric materials, field emission.Many approaches have been developed to synthesize zinc oxide nanomaterials. Aqueous solution has been attracting tremendous interest of the majority of scholars due to the advantages of simple-operation, low-equipment-requirements, low-cost, easy repeatability, environmentally friendly, easily large-scale preparation. In this paper, zinc oxide micro/nanostructures with different morphologies were synthesized by low temperature solution route. The effect of process parameters on the structure of nano ZnO was discussed, and controllable preparation of zinc oxide nanomaterials was realized. The main contents of this paper are as follows:zinc oxide nanoparticles were prepared in the solution system with zinc sulfate, ammonia, sodium dodecyl sulfonate as raw materials. The impact of different parameters on the size of the ZnO nanoparticles was studied.1) ZnO nanoparticles with well-crystallized, uniform size, good dispersion were prepared by direct precipitation in solution. The study found that the concentration of reactants, calcination temperature and surfactants play an important role in ZnO particles size. With the increase of the concentration of reactants and calcination temperature, the size of ZnO nanoparticles showed an increasing tendency. Adding a surfactant could effectively reduce the aggregation of the products.Rod-like zinc oxide namomaterials were prepared by hydrothermal synthesis with zinc sulfate and sodium hydroxide as the main raw material. The effect of OH’concentration, hydrothermal reaction time and reaction temperature on the morphology of the products and photocatalytic activity were discussed.1) When the concentration of OH" is lower, zinc oxide obtained is a mutually stacked sheet-like structure. With the increase of the concentration of OH-, the morphology of zinc oxide becomes into dandelion-like structure having a conical self-assembly. Further more, with the concentration of OH-increasing, the products were obtained as the thickness of the irregular unevenness of the rod-like structure. The morphology of zinc oxide gradually changes from irregular rod-like structure to the rules of the rod-like structure with increasing reaction time. As the hydrothermal temperature rises, the morphology of zinc oxide becomes tapered at both ends of the rod-like structure.2) Zinc oxide prepared in the reaction temperature for90℃, the reaction time for9h, Zn2+/OH-for1:8have an excellent photocatalytic performance for methylene blue solution.ZnO micro/nanosheets film structures were synthesized by low-temperature aqueous solution routes, and the growth mechanism were discussed.1) The prepared micro/nanoplates, interleaved with each other to form a reticular structure were perpendicular to the substrate growth.2) ZnO micro/nanosheets film structures were prepared in a lower temperature of40℃. The morphology of micro/nanosheets changes when the reaction time arises to5h, the edges of micro/nanosheets become smooth and toppling. The increase of the reaction concentration could promote ZnO micro/nanosheets growth. The base materials have a little effect on the morphology of films.3) The formed sheet structure mainly due to the larger solution pH value and the presence of (CH)6N4in the solution.