Fabrication And Electrochemical Properties Of 3D Hollow Graphene Balls

Graphene is a two-dimensional material which is only a single atom thick.Graphene has excellent mechanical performance,physical and chemical properties,thus attracting the attention of the researchers.But the two-dimensional structure greatly reduced the contact area between the graphene and solution,so applications of graphene in electrochemical sensor are greatly limited.3D hollow graphene balls have three-dimensional hollow structure.Compared with the two-dimensional graphene,3D hollow graphene balls have excellent electrochemical performance,which retain the excellent performance of two-dimensional graphene with larger specific surface area,stable deformation field and larger contact area between the graphene and solution.In this paper,we reduce nickel chloride to get nickel spherical particles template.Then graphene coated on the surface of nickel particles template through the carbide cladding method.After Etching the nickel,we prepared the 3D hollow graphene balls.3D hollow graphene balls were characterized by scanning electron microscope(SEM),transmission electron microscope(TEM),X-ray diffraction(XRD)and Raman spectroscopy(Raman).It can be seen that 3D hollow graphene balls are complete and the sizes of them are about 100 nm in the SEM and TEM figures.The dispersivity of the 3D hollow graphene balls is good.XRD shows that the 3D hollow graphene balls are pure without impurities.Raman shows that 3D hollow graphene balls are low layer structures and few defects.The 3D hollow graphene balls were transferred onto ITO coated glass using a spray coating method.The 3D hollow graphene balls/ITO was acting as an electrode to detect Levodopa(L-DOPA).We use the cyclic voltammograms(CV)and differential pulse cyclic voltammograms(DPV)of 3D hollow graphene balls/ITO electrode to test the electrochemical performance.The experiment results show that the sensitivity of the 3D hollow graphene balls/ITO electrode is 0.48?A·?M-1 for L-DOPA.It proved that the electrode has good selectivity of the DPV determination of L-DOPA in the presence of uric acid(UA).And the electrode has excellent repeatability and stability.So 3D hollow graphene balls/ITO electrode can be used in the electrochemical biosensor for the detection of L-DOPA.