Preparation And Electrochemical Properties Of Three Dimensional Graphene/Au NPs Composites

Graphene is a single layer of carbon atoms through the sp² hybrid arranged in the honeycomb hexagonal two-dimensional planar crystal,only 0.334 nm thick.It has the advantages of large specific surface area,excellent electrical,optical,thermal and mechanical properties,so that it has obvious advantages in electrochemical detection and analysis,so it is an ideal material for preparing high performance electrochemical sensors and catalysts.Three-dimensional graphene?3D Gr?is a network structure composed of two-dimensional graphene.Compared with two-dimensional graphene,the 3D Gr has a larger specific surface area and is expected to have more favorable electrochemical sensing and catalytic properties.The combination of graphene and other nanomaterials?for example,metal nanoparticles?can further improve the electrochemical performance of graphene and expand and enhance the sensitivity and selectivity of its electrochemical effects through the synergistic effect of'composite materials.In this research,three-dimensional graphene was prepared by chemical vapor deposition?CVD?,gold nanoparticles were prepared by seed crystal method.The nanoparticles were prepared by UV-Vis,SEM,TEM,Raman and other equipment on the preparation of materials for characterization analysis.Three-dimensional graphene/gold nanoparticle composites?3D Gr/Au NPs?were prepared by electrophoretic deposition as hydrogen peroxide?H₂O₂?electrochemical sensors,and their electrochemical performance was tested and analyzed by electrochemical workstation.The prepared 3D Gr/Au NPs composites were modified,the graphene-based composites without surfactant were obtained by annealing and optimizing the preparation of Au NPs,their electrochemical properties were tested respectively.The effects of three different composites on H₂O₂ sensor were studied.The specific research contents and conclusions are as follows:?1?The 3D Gr prepared by CVD method has a complete three-dimensional hole structure and excellent mechanical properties.?2?The Au NPs were prepared by seeding method and prepared in two steps.The Au NPs with uniform dispersion and high stability were prepared successfully.They showed a spherical shape and average particle size was 19 nm.?3?The effects of deposition voltage and deposition time on the preparation of the composites were investigated by electrophoretic deposition.When the deposition time is 1.5 h and the deposition voltage is 10 V,the Au NPs are uniformLy dispersed on the surface of the 3D Gr and the nanoparticles coverage is the highest.?4?The electrochemical performance of the 3D Gr/Au NPs composites were tested.It was found that the composites material exhibited good electrochemical sensing performance for H₂O₂ with a response time of 3 s and a linear detection interval of 0.05-1.75 mM.?5?The 3D Gr/Au NPs composites were annealed and the effect of annealing time how to influenced the properties of the composites was explored.It was found that after a hour annealing,the composite exhibited excellent electrochemical sensing performance for H₂O₂ sensor,the response time is only 1 s and a linear detection interval of 0.02-3 mM.?6?The preparation process of Au NPs was simplified and the monovalent gold nanoparticles were prepared successfully.Particle size between 100-200 nm.The particles showed morphology spherical or rod-like.The 3D Gr/monovalent gold particles composites were also prepared by electrophoretic deposition and the electrochemical properties were studied.The material also exhibits good electrochemical sensing properties for H₂O₂.The detection response time is 6 s,the minimum detection limit is 20 ?M,the linear detection interval is 0.02-1.2 mM,the electrochemical performance is worse than the former,but the preparation process is simple and less time consuming.Thus,it is expected to realize mass production.