Synthesis And Photocatalysis Performance Of Zinc Oxide/Reduced Graphene Oxide Composites

Zinc oxide(ZnO)is an excellent photocatalytic semiconductor material with a direct band gap(Eg=3.27 eV)and the exciton binding energy(60 meV),which shows a unique physical and chemical properties in optoelectronics,biology,chemistry and other fields.With the advance of photocatalytic technology,ZnO shows a good prospect,however,it is found that ZnO has some defects in the photocatalytic process,such as the high recombination rate of photo-generated electron-hole,prone to light corrosion and the narrow range of light response and so on.The photocatalytic property of ZnO was improved by the combination carbon materials and noble metal.In this paper,the rod-like ZnO prepared by solvothermal method,influence the photocatalytic performance of the reaction temperature and time;and then the subject combined with reduction graphene oxide(RGO).a noble metal silver(Ag),the ZnO-based compound photocatalyst were prepared to study effect of compound on the catalytic properties,finially,aim to prepare the ZnO-based photocatalyst that has excellent properties.The specific research contents are as follows:(1)With zinc acetate as initial raw materials,water and ethylene glycol mixed solution as a solvent,adding the ethanolamine.using the solvent thermal method to prepare ZnO.The results of XRD and SEM tests showed that the ZnO is a six-party crystal structure with a rod like shape.Experimental results show that the reaction temperature was 180?,reaction time was 4 h,while the photocatalytic properties of ZnO is best.Under ultraviolet light conditions to photodegradate MO when the dosage is 1.5 g·L-1,MO at a concentration of 10 mg·L-1,pH value of 9,under UV irradiation of 40 min the solution photodegradation rate reached at 99.8%.(2)With zinc acetate and GO that were made by Improved Hummers method as the raw material,adding ethanolamine,ZnO/RGO composits prepared by solvothermal method.By a way to reserch the photocatalytic propertiy of ZnO/RGO make sure the law amount of GO.The results show:ZnO/RGO has the best performance when the amount of GO reached 2 mg.The characterization by XRD?SEM,the results show that RGO was coated on surface of the rod ZnO.Compared ZnO with ZnO/RGO in photocatalytic Performance we can concluse that ZnO/RGO has not the visible response activity,while under UV irradiation 30 min,ZnO/RGO photocatalytic degradation of MO photodegradation rate increase of 25.1%.(3)Prepared Ag/ZnO/RGO composites by wet chemical,Studied the effects of the concentration of AgNO3 influence Ag/ZnO/RGO photocatalytic properties,the experimental result shows that the concentration of AgNO3 was 0.001 mol/L has the highest catalytic activity.The characterization of catalysis by XRD,SEM,EDS,TEM.Its results show that the face-centered cubic structure Ag supported on the surface of the rod-like ZnO and ZnO/RGO,and did not enter the crystal structure.The degradation rate of ZnO/RGO reaches 99.6%in 30 min under UV irradiation,compared with ZnO the degradation rate improved 17.2%.(4)Experiments were made to test the stability of them.The doped-Ag catalyst have better photocatalytic activity,especially the Ag/ZnO/RGO,after 3 cycles the retention rate is 87.10%and ZnO/RGO is 59.4%.We also studied ZnO,ZnO/RGO,Ag/ZnO,Ag/ZnO/RGO photocatalytic degradation kinetics of MO and the results showed that the photocatalytic degradation of MO belong to first order kinetics.With Ag,RGO double electron capture agent Ag/ZnO/RGO photocatalytic activity was better than other catalysts.Under UV light conditions the degradation rate constant of photocatalytic degradation MO kapp=0.15595 min-1,which is 3.87 times of ZnO(Kapp=0.04011min-1),1.77 times of ZnO/RGO(kapp=0.0882 min-1)and 1.52 times of Ag/ZnO(kapp=0.10292 min-1).