The Research Of Synthesis, Fluorescence Properties And Photocatalytic Performance Of ZnO Mico/Nano Structures

ZnO as a kind of n-type direct band gap semiconductor materials with uniquephysical and chemical properties has been widely applied in many fields, such asphotoelectronic devices and photocatalytic materials. Many properties of ZnOnanomaterials are related to the morphology, size and internal defects of the crystals.In recent years, people tried to use the simple way to synthesis ZnO nanomaterialswith different morphologies, sizes and internal defects, and then studied its effects onthe properties of materials further. In this paper, the ZnO micro/nano structures weresynthesized by the simple solution in-situ growth using copper mesh and aluminumfoil as substrate, respectively. Their fluorescence and photocatalytic properties werestudied.Specific contents as follows:1. Different ZnO micro/nano structures were synthesized by the simple two-stepin-situ solution growth method under the condition of low temperature90℃, by usingdifferent substrates. ZnO micro/nanorods which coated on the surface of the copperfiber and formed networks were synthesized by using copper mesh as template. ZnOmicro/nanosheets were synthesized by using aluminum foil as template. Both of themwere hexagonal wurtzite structures. Results of absorbance test showed that both ofZnO micro/nanorods and micro/nanosheets had obvious absorption in ultraviolet band.The band gaps were3.20eV and3.23eV, respectively, which were calculated by Taucformula.2. ZnO micro/nanorods with the same morphology and different sizes had beencontrollably synthesized by adjusting the dropping quantity of ammonia into thesolution. The room temperature photoluminesce spectra showed a UV emission peakand a green orange light emission band. The former was the intrinsic photoluminescepeak of ZnO, which was caused by the recombination of the band edge exciton. Thestrong green orange light emission of the sample could caused by the recombinationof the holes in the top of the valence band and the electrons in the donor levels of double ionized oxygen vacancy and single ionized oxygen vacancy based on ZnOintrinsic defect band theory. These results meant that there were a large amount ofoxygen vacancy defects in the samples, and the relative concentrations of doubleionized oxygen vacancy defects could be regulated by adjusting the quantity ofammonia.3. Using Cu based ZnO micro/nanorods films and Al based ZnOmicro/nanosheets films as photocatalyst to degrade RhB, the degradation rates were25.3%and30.1%, respectively, after exposure to the UV light for2.5hours. Thecatalytic activity of micro/nanosheets was better, which perhaps resulted from its large specific surface area and the higher fraction of exposed (0001) and (0001) ZnOpolar facets. The low quantities and the larger sizes of reaction catalyst in experimentmay do eventually result in low photocatalytic activity of two kinds of ZnO materials.