Preparation And Photocatalytic Property Of ZnO Nano-composite Materials

In thesis, two novel ZnO nano-composite materials of photocatalyst (ZnO/GO andCe⁴⁺/ZnO) were successfully designed and prepared. Their catalytic activities wereevaluated by measuring the decolorization efficiency of MO in aqueous solution. Inaddition, the effects of the content of the nanocomposite photocatalysts andcalcination temperature and light source on photocatalytic activity were investigated.These composites were also characterized using TEM, XRD, UV-Vis and IRtechniques.Part I IntroductionThe concepts, methods, histories and new developments of nano-compositematerials of photocatalyst were detailed introduced. We pointed out the reasons whyto select the search project.Part II Preparation and Photocatalytic Property of ZnO/GO composite material withhighly photocatalytic performance via an improved two-step methodZnO/graphene oxide （ZnO/GO） hybrid materials were successfully preparedbygrowing ZnO nanocrystals directly on GO sheets. This was achieved by animprovedtwo-steps method, in which Zn2+ions were fully adsorbed on GO sheets and Zn（OH）2was coated by a slowly hydrolyzed ZnC2O4/NH3H2O solution, followed bytransformed to ZnO and crystallized into nanocrystals with thermal treatment, andunfolding of GO sheets by the further exfoliation. The adsorptive and photocatalyticperformances of the as-prepared materials can be enhanced by changing the ratio ofhybridizing ZnO and GO. The improved photocatalytic property of ZnO/GO hybridmaterials is ascribed to the enhanced adsorption of MO and the quick electron transferfrom excited ZnO particles to GO sheets and the activation of MO moleculesPart III Preparation and Photocatalytic Property of Ce-doped ZnO photocatalytic(Ce⁴⁺/ZnO) nano-composite photocatalytic materials of via a template mothodCe-doped ZnO photocatalytic (Ce⁴⁺/ZnO) nano-composite photocatalytic materialswith hollow fiber structurewere prepared by a two-steps method characterized byTEM, XRD, UV-Vis, FTIR and potential measurements. The influence of calcination conditions on the photocatalyticproperty of the nano-composite materials wasevaluated by using the degradation of methyl orange （MO） as the model reaction. Theresult exhibits that the sample obtained under500℃and2.5h shows the optimalphotocatalytic property; Results showed that obtained materials(Ce⁴⁺/ZnO) havehollow fiber structure. The decolorizing efficiency of MO solution is up to90%overCe⁴⁺/ZnO when reaction time is2.5h under UV light irradiation while the efficiencyis only68.9%over ZnO. And the efficiency remains above70%when it is reused for5cycles and it is easily removed from the system.