Studies On The Controllable Preparation And Photocatalytic Activity Of Znic-based Photocatalyst

At present,photocatalytic oxidation technology get the attention of people,mainly using it to break down pollutants in the water.Although this emerging technology has made great achievements in the decades of development,the application on a large scale still has some problems in the industrial production.The photocatalytic materials generally have wide band gap,the sunlight utilization is not high,which restricts the development and application of this technology in the life.Therefore,reducing the width of the gap and making full use of the sun have become a key to prepare a new high efficiency catalyst.In this study,ZnO、ZnO/CdS、ZnCO3/CdS、ZnS、Bi2S3/ZnS and CdS/ZnS are synthesized respectively by using hydrothermal method.And its photocatalytic properties are studied in order to find the best preparation conditions.Surface morphologies and interfacial properties of the above samples are investigated by using X-ray diffraction(XRD),scanning electron microscope(SEM),UV-visible diffuse(UV-Vis),fluorescence spectroscopy(PL) technologies and so on. And under the simulated sunlight or visible light irradiation,using reactive brilliant blue(KN-R) as model pollutant and conducting photodegradation experiments to study the ability of photocatalytic degradation. In this experiment,the main contents and conclusions are as follows:(1) The preparation and photocatalytic performance of ZnO photocatalyst.With zinc nitrate and six methyl tetramine as raw materials to the preparation of Zn O photocatalyst.It was investigated for the different concentrations of six methyl tetramine to control the morphology and photocatalytic properties of ZnO.The highest photocatalytic activity of the as-obtained ZnO can be achieved under simulated sunlight irradiation when the the concentrations of six methyl tetramine is 0.3mol/L,the decolorization rate of KN-R is 61.77% in 150 min.With zinc nitrate and sodium hydroxide as raw materials to the preparation of ZnO photocatalyst.It was investigated for the different mole ratio of zinc nitrate and sodium hydroxide to control the morphology and photocatalytic properties of ZnO.The highest photocatalytic activity of the as-obtained ZnO can be achieved under simulated sunlight irradiation when the mole ratio of zinc nitrate and sodium hydroxide is 1:5,the decolorization rate of KN-R is 95.71% in 90 min.With zinc nitrate and six methyl tetramine and citrate or EDTA as raw materials.By adjusting dosage of citrate or EDTA to the preparation of ZnO photocatalyst.It was investigated for the different dosage of citrate and EDTA to control the morphology and photoelectric properties of ZnO.The highest photocatalytic activity of the as-obtained ZnO can be achieved under simulated sunlight irradiation when the dosage of EDTA is 5mM,the decolorization rate of KN-R is 90% in 90 min.The highest photocatalytic activity of the as-obtained ZnO can be achieved under simulated sunlight irradiation when the dosage of citrate is 10 mM,the decolorization rate of KN-R is 92.31% in 90 min.(2) The preparation and photocatalytic performance of ZnO and ZnCO3 photocatalyst modified by CdS.ZnO/CdS and ZnCO3/CdS composite photocatalyst has been synthesized by hydrothermal method.It was investigated for the different mole ratio of cadmium nitrate and zinc nitrate to control the morphology and photocatalytic properties of composite photocatalyst.The highest photocatalytic activity of the as-obtained ZnO/CdS can be achieved under simulated sunlight irradiation when the mole ratio of cadmium nitrate and zinc nitrate is 1:2,the decolorization rate of KN-R is 98.61% in 60 min.(3) The preparation and photocatalytic performance of ZnS、Bi2S3/ZnS and CdS/ZnS composite photocatalyst.A ZnS photocatalyst has been synthesized by hydrothermal method.It was investigated for the different dosage of ethylenediamine to control the morphology and photoelectric properties of ZnS.The highest photocatalytic activity of the as-obtained ZnS can be achieved under simulated sunlight irradiation when the dosage of ethylenediamine is 5mL, the decolorization rate of KN-R is 90.24% in 90 min.With cadmium nitrate and bismuth nitrate doped ZnS to the preparation of Bi2S3/ZnS and CdS/ZnS composite photocatalyst,and the doped ZnS have the best photocatalytic activity.It was investigated for the different doping amounts to control the morphology and photocatalytic properties of Bi2S3/ZnS and CdS/ZnS composite photocatalyst.The highest photocatalytic activity of the as-obtained Bi2S3/ZnS can be achieved under visible light irradiation when the doping amounts of Bi2S3 is 1%,the decolorization rate of KN-R is 72.97% in 90 min.The highest photocatalytic activity of the as-obtained CdS/ZnS can be achieved under visible light irradiation when the doping amounts of CdS is 1%,the decolorization rate of KN-R is 74.32% in 150 min.