Preparation And Modification Of ZnWO₄ Photocatalyst

Photocatalytic has high value in environmental protection and pollution control.ZnWO₄ as a new photocatalytic material,that the ZnWO₄ physical and chemical properties are stable,and it is not easy to hydrolyze.It has the ability to resist strong light and radiation,high excitation energy,and has certain catalytic activity.However,the utilization rate of single-phase ZnWO₄ for visible light is extremely low,which hinders the application of ZnWO₄ in practical production.Therefore,the following method was used to enhance the visible light response of ZnWO₄.（1）ZnWO₄ was prepared by hydrothermal method.The effects on the structure and properties of the ZnWO₄ were investigated by surfactant（CTAB）and hydrothermal time,then SEM and XRD were used to characterize the ZnWO₄.Photocatalytic degradation experiment of the ZnWO₄under the visible light was carried out.The results show that CTAB had a certain effect on the morphology of the catalyst,which will affect the catalytic activity of the catalyst.The hydrothermal time affects the crystal growth of the ZnWO₄ and also had a certain effect on the catalytic activity.（2）BiPO₄@ZnWO₄ photocatalyst was prepared by hydrothermal method.XRD,BET,SEM and other instruments were used to characterize the BiPO₄@ZnWO₄.The photocatalytic degradation experiment of the BiPO₄@ZnWO₄ under visible light was carried out.The experimental results show the ZnWO₄ and BiPO₄ prepared by the hydrothermal method were both monoclinic crystals.20%BiPO₄@ZnWO₄ BET surface area was larger,and the band gap of the ZnWO₄ was 3.47 e V.After compounding BiPO₄,the band gap was reduced to 3.3 e V,and the band gap became smaller.When the BiPO₄compound ratio was 20wt%,the degradation of rhodamine B reached 99%.Under the irradiation of visible light,the instantaneous photocurrent of the 20%BiPO₄@ZnWO₄was higher than that of ZnWO₄.It had rapid photoelectric response and better photocatalytic activity.（3）The CoWO₄ modified ZnWO₄photocatalyst was prepared by hydrothermal method,the CoWO₄@ZnWO₄ was characterized.Under visible light,the photocatalytic degradation test of the CoWO₄@ZnWO₄ was carried out.The results show the crystallinity was improvedthe,but XRD diffraction peak of the CoWO₄ was similar to that of the pure the ZnWO₄.It changed the utilization efficiency of visible light,and the edge of the absorption band of the CoWO₄@ZnWO₄ obviously shifted to a longer direction.On the other,at 1:3,the photocatalytic activity of CoWO₄ complex ratio was the highest.The migration ability of photogenerated carriers of the CoWO₄@ZnWO₄has higher photocatalytic activity and was stronger than that of the ZnWO₄.