Fabrication And Electrochemical Properties Of Graphene/ZnO Nanoflowers Composite Materials

Zinc oxide(ZnO)is an excellent semiconductor material with excellent optical,catalytic and electrochemical properties.And the ZnO is extremely rich in appearance,such as nanorods,nanowires,nanotubes,nanometers,nanoflowers,and so on.In particular,three-dimensional zinc oxide nanoflowers(ZnONFs)are more than the surface area of one-dimensional or two-dimensional material such as nanowires and nanometers.As a sensor electrode,it can greatly increase the contact area with the solution and improve the electrochemical properties of ZnO in the sensor.In order to further improve the ZnO in electrical conductivity and easy adsorption of biomolecules faults,graphene deposition on ZnO nanoparticle surface by chemical vapor deposition(CVD),get graphene/ZnONFs composite material.Then the morphology and structure of graphene/ZnONFs composite materials were characterized by scanning electron microscope(SEM),Raman and XRD.It can be seen from the SEM graph that the length of nanoflowers branch of ZnO is 2.5 μm with a diameter of 50 nm and its distribution is uniform and has a larger than surface area.The comparison of the XRD figure with the standard PDF card can determine the structure of the material as graphene/ZnONFs.Raman spectra shows that the prepared graphene is a small structure.Finally,we constructed ZnONFs/ITO electrode by means of automatic spraying,and based on the electrode deposited a layer of graphene by CVD method,successfully constructed the graphene/ZnONFs/ITO electrode,and then by electrochemical workstation for electrochemical detection of LD.The electrochemical analysis of the electrode was carried out mainly by cyclic voltammetry(CV),differential pulse cyclic voltammetry(DPV)and DPV test with uric acid(UA)interference.The sensitivity of ZnONFs/ITO electrodes at the LD concentration of 2.5-40 μM is 0.10 μA·μM-1.The sensitivity and measured limit of detection of the graphene/ZnONFs/ITO electrode for LD are 0.32 μA·μM-1 and 1 μM in the range of 1-60 μM,respectively.The electrode can accurately detect levodopa in the presence of uric acid.Meanwhile,the electrode shows good repeatability and stability.