Study On The Preparation And Photocatalytic Application Of Nano Zinc Oxide-based Composite Materials

Due to the features of non-toxic,good biocompatibility,and high chemical stability,nano-zinc oxide(nano-ZnO)has received widespread attention.However,the zinc resources of our country are scarce while the consumption of nano-ZnO is quite large,and a great amount of zinc is generated during its production and application process,which will aggravate environmental pollution;the wide band gap of nano-ZnO leads to a decrease in the utilization rate of sunlight,and photogenerated electron-hole pair is extremely easy to recombine,which seriously affects its photocatalytic efficiency.This paper focusing on above problems,nano-ZnO-based composites were prepared.The main study contents are as follows:1.Study on the preparation and photocatalytic application of nano-ZnO/calcium carbonate composite material(ZnO/CaCO3).(1)Using sodium carbonate and zinc sulfate as precipitating agents,ZnO/CaCO3 was prepared by direct precipitation method,and characterized by XRD,SEM,TEM,FT-IR,XPS and DRS.The composite material was used to the photodegradation of Rhodamine B(RhB)under visible light.The results indicated that the degradation rate of ZnO/CaCO3 to RhB within 180 min was 96.6%under better conditions.(2)ZnO/CaCO3 was prepared by a method combining ball milling and spray drying for photocatalytic degradation of RhB under visible light.The effects of ZnO/CaCO3 preparation method,nano-ZnO content and concentration of ZnO/CaCO3 on photocatalytic activity were studied.Under optimized conditions,the degradation rate of RhB by ZnO/CaCO3 within 180 min was 94.8%.ZnO/CaCO3 with low ZnO content has an application effect that exceeds pure nano-ZnO,achieving the goal of zinc reduction.2.Study on the preparation and photocatalytic application of nano-ZnO/graphene composite material(GR/ZnO).In the process of preparing graphene via combining ball milling and liquid phase exfoliation,modified nano-ZnO was used as an auxiliary to assist exfoliation of graphite to obtain high-yield graphene and GR/ZnO at the same time.The modified nano-ZnO was prepared by direct precipitation method and high-temperature calcination method,and its morphology was spherical and rod-shaped,respectively.The prepared graphene and GR/ZnO were characterized by UV-vis,SEM,TEM,Raman,XRD,XPS,and EIS.The influence of the modifier type,the mass ratio of graphite to nano-ZnO,the ball milling time,the ultrasonic time,the mass ratio of ball to material and the morphology of nano-ZnO on the concentration of graphene were studied detailly.GR/ZnO was used for photodegrading RhB and Methylene Blue(MB)under visible light,showing higher photocatalytic activity for RhB.The mechanism of nano-ZnO assisted exfoliation of graphite and the photocatalytic mechanism of GR/ZnO were studied.