Study On The Preparion And Photo-catalytic Capability Of Metal Ion Doped Nano Zinc Oxide

In the field of photocatalysis,Nano-ZnO as a new type of functional materials has a good application prospects, because of its low-cost, non-toxic, high catalytic efficiency, structure and performance of the relatively stable characteristics. However, as their effect of photocorrosion and low catalytic efficiency, so the catalytic activity must to be further enhanced. In addition, because of its band gap is 3.2ev, absorption wavelength threshold is mostly in the ultraviolet zone and its low utilization efficiency of sunlight . again, because of the high carrier recombination rate and the low quantum efficiency, so how to enhance its photocatalytic efficiency effectively become the research hotspot and it's necessary to study the photocatalytic activity of nano-ZnO and its application in the field of photocatalytic in-depth.Nano-ZnO , Fe-doped nano-ZnO and Cu-doped nano-ZnO were prepared by sol-gel method.The crystal structure was characterized by XRD,FT-IR,UV-Vis and FS.The photocatalytic activity of catalysts was studied under the irradiation with ultraviolet light with the methyl orange as the objective decomposition substance.The results showed that:Nano-ZnO powders was prepared with Zinc acetate dihydrate (Zn (CH3COO) 2·2H2O) as a precursor, Ethyl alcohol (EtOH) as solvent, diethanolamine (DEA) as a stabilizing agent. The obtained nano-ZnO was hexagonal wurtzite structure and the average diameter was about 36nm.Fe-doped nano-ZnO was hexagonal wurtzite structure and the average diameter was about 34.5nm. IR showed that there is characteristic absorption peaks of ZnO and no iron characteristic absorption peaks. The 0.5%Fe/ZnO exhibited red-shift in the UV absorption spectra obviously, the absorption of visible light was enhanced and the catalytic activity of visible light was improved. iron doping didn't not lead to a new luminescence phenomenon, the change of fluorescence intensity was contrary to the change of photocatalytic activity of samples.Cu-doped nano-ZnO was hexagonal wurtzite structure and the average diameter was about 34.5nm, the doping of copper inhibited the growth of nano-ZnO particles effectively during preparation, IR showed that there is characteristic absorption peaks of ZnO and no copper characteristic absorption peaks. The 0.5%Cu/ZnO exhibited red shift in the UV absorption spectra, and the catalytic activity of visible light was enhanced. A new light-emitting phenomenon wasn't brought by Copper doping, but the response range and intensity of fluorescence were affected, the change of fluor escence intensity was contrary to the change of photocatalytic activity of samples, that is, the lower the fluorescence intensity of sample was, the higher the photocatalytic activity was.The study of photocatalytic activity for methyl orange showed that: The optimal iron loadings of ZnO was 0.5%, the optimal Cu loadings was 0.5%. The extra 19%, 23% degradation rate of methyl orange could be found under 240min irradiation of ultraviolet light, when initial concentration of methyl orange is 20mg/L,dosage of photocatalyst is optimally 0.1g/L,pH=7. The photocatalytic degradation kinetics followed pseudo-first order reaction.