Fabrication And Electrochemical Properties Of Three Dimensional Graphene/Gold Nanoparticle Composite Materials

Graphene is an ideal material for constructing electrochemical biosensor electrodes because of its large specific surface area,high mechanical strength,good electrical conductivity and biocompatibility.However,graphene,as a two-dimensional?2D?material,has a small contact area with a solution,resulting in the decline of its ability to detect biological molecules.Gold nanoparticles?Au NPs?are also ideal materials for detecting biomolecules due to their excellent catalytic properties and biocompatibility.However,the easy agglomeration among nanoparticles limits their development in the field of biosensors.Gold nanoparticles are attached to the surface of three-dimensional graphene not only solve the problem that the contact area between the 2D graphene and the solution is small and the gold nanoparticles are easy to agglomerate,but also the synergistic effect of the two materials can improve the performance of the biosensor.In this paper,nickel nanoparticles were prepared using a liquid phase reduction method,and then it was sintered into a three dimensional template.Three-dimensional graphene with small pore size was prepared by chemical vapor deposition?CVD?.Finally,The Au NPs were dropped onto the 3DGR and freeze-dried to obtain the three-dimensional graphene/gold nanoparticles?3D GR/Au NPs?composite.The prepared materials were characterized by scanning electron microscope?SEM?,transmission electron microscope?TEM?,X-ray diffraction?XRD?,energy dispersive spectrum?EDS?and Raman spectroscopy?Raman?.The XRD analysis confirmed that the composite consisted of 3D GR and Au NPs.The 3D GR is multilayer graphene with high quality through TEM and Raman.From the SEM images,it can be seen that 3D GR has a three-dimensional porous structure.From the SEM images,it can be seen that 3D GR has a three-dimensional porous structure.Combined with EDS analysis,Au NPs are evenly distributed on the surface of 3D GR.Combined with EDS analysis,Au NPs are uniformly distributed on the3D GR surface.3D GR and 3D GR/Au NPs were transferred to the surface of indium tin oxide?ITO?glass to construct 3D GR/ITO and 3D GR/Au NPs/ITO electrodes.Dopamine?DA?and uric acid?UA?were electrochemically measured using the prepared electrode through a three-electrode system.The sensitivity of the 3D GR/Au NPs/ITO electrode to DA and UA in the range of 0-60?M was 1.78?A·?M^-1 and1.53?A·?M^-1,respectively,and the detection limits of DA and UA are both 0.1?M.When DA and UA were detected as interfering substances,the two peaks were clearly distinguished and the sensitivity remained basically unchanged.Meanwhile,the electrode has good repeatability and stability,and it can also be used for the detection of actual samples.