Preparation Of PDDA-RGO/ZNO Composite And Its Application In Uric Acid Detection

Graphene is a new carbon material with two-dimensional conjugate structure,a large specific surface area,extraordinary electron mobility and high chemical stability,It has been discovered to be applied to the research field of energy storage,photocatalysis,electronic and chemical sensors.However,the dispersion of graphene in water is poor and it is easy to agglomerate.Which has seriously hindered its application in various fields,and the zero band gap structure of graphene has greatly limit its development in some fields.Therefore,surface modification of graphene has become a hot topic among scholars in recent years.In this experiment,graphene oxide(GO)was prepared by modified Hummers method.Then the Poly diallyldimethylammonlum chloride modified graphene/zinc oxide composite materials(PDDA-RGO/ZnO)were prepared under different conditions by simultaneous reduction of grapheng oxide(GO)and zinc nitrate salt solution as precursor with hydrazine hydrate as the reducing agent.and the optimum conditions for the synthesis of materials obtained by the electrochemical signal strength through the cyclic voltammetry test.The GO,PDDA-RGO,RGO/ZnO and PDDA-RGO/ZnO were characterized by transmission electron microscopy(TEM),scanning electron microscopy(SEM),X ray diffraction(XRD),UV absorption spectroscopy(UV),infrared absorption spectroscopy(FT-IR)and X ray photoelectron spectroscopy(XPS).The results showed that the GO and zinc nitrate salt solution were simultaneously reduced during the synthesis process of PDDA-RGO/ZnO,and zinc oxide particles were evenly distributed on the surface of modified graphene,and the dispersion of the composite material in water is greatly improved compared with GO.In addition,the electrochemical properties of GO,PDDA-RGO,RGO/ZnO and PDDA-RGO/ZnO were detected by cyclic voltammetry and electrochemical impedance spectroscopy.The results showed that PDDA-RGO/ZnO has a higher electron transfer rate,and its modified electrode has better electrochemical conductivity.The PDDA-RGO/ZnO material was configured to 0.5 mg/mL solution,and the electrochemical sensor was prepared by modified the glassy carbon electrode.Tthe electrochemical performance of the sensor was tested by cyclic voltammetry and linear scanning,and the results showed that the sensor exhibits significant electrocatalytic activity for uric acid(UA)and has good resistance to reterference,repeatability and stability.In the range of UA concentration of 0.02-0.1,mmol/L and 0.1-1.0 mmol/L,the sensor showed a good linear relationship and the detection limit for detecting uric acid was 15.9 nmol/L(S/N=3).