Preparations And Properties Of Porous Zinc Oxide By Dealloying Method

zinc oxide is ?-? compound semiconductor and has a wide banfgap eneergy(3.37 eV)and a large exciton binding energy(60 meV).Porous zinc oxide have good application because of their huge specific surface area,therefore in the many filed.Deu to its favourable structural,optical and catalytic properties,zinic oxide has been widely used as sensors,super hydrophobic material,photocatalyst,in solar cells,field-emission device.In this thesis,research on the preparation of porous structured zinc oxide,synthesis via dealloying and The ceramic treatment method.Scanning electron microscopy(SEM),X-ray diffraction(XRD),instrusive mercury measurements,photoluminescence(PL)spectra,Uv-vis spectrophotometer testing are adoped to characterize the properties of the samples.The main content and some results are as follows:(1)After the molten alloy,quenching and rolling preforming processing.Through the analysis of binary phase diagram we found that there are two two phase exist in the organizations:?-Phase and ?-Phase.To obtain a single solid solution we studyed some influencing factors include Solid solution temperature,solution time and cooling rate.Solid solution temperature rise,prolong the solid solution time and increase the cooling speed can significantly reduce the number of ?-Zn phase,The basic solid solution alloy when the temperature to 480?,extended to 6 h,and there no signs show any over burnt.(2)The preparation of porous zinc oxide has the structure of frame made of Layer plate,Porous morphology,structure,affected by many factors:Al content,concentration of NaOH,corrosion,etc.Under the specific experimental parameters of Al 55%,n(NaOH):n(Al)= 2:1,dealloying for 10?19 h and the thickness of 0.5 mm we obtian the porous zno morphology characteristics in good condition.Mercury injection is used to analyze the various parameters of the pore size distribution and specific surface area show that the porous zinic oxide with the Alloy composition of 45%Zn55%Al show good appearance.The photocatalytic activity of porous zinc oxide microspheres was investigated by photodegradation of methyl orange under ultraviolet irradiation.The photocatalytic(3)results revealed that 45%Zn55%Al photocatalytic effect is better than 30%Zn70%Al and 60%Zn40%.The methyl orange solutionwas totally photodegraded by the porous ZnO microspheres after 30 h.When the solution is acidic or alkaline the photocatalytic efficienc of porous zinc oxide is down sharply,emote to 10%.Oxidant H2O2 can significantly increase thephotocatalytic efficiency of porous zinc oxide.The porous zinc oxide also have good photoluminescence properties,We found that between 450 nm to 550 nm appeared a wide green peak,This particular peak attribute to the oxygen vacancies and zinc interstitials.The samples of 30%Zn70%Al has the hightest absolute absorption intensity of green light,which shows that the number of the defects grown as Al content increases.