The Preparation And Electrochemical Properties Of Graphene/Silver Nanocomposites

Graphene is widely used in energy storage materials because of its unique electronic band structure,which is widely used in energy storage materials.Adding Ag nanoparticles on the surface can improve the electrochemical performance of composites and expand their application.In this thesis,the graphene oxide surface was functionalized by the amination modification method,and the graphene/nanosilver composites was synthesized.The electrochemical performance and the electrochemical response to heavy metal ions in water were studied.FTIR analysis of graphene oxide and functionalized graphene oxide shows that graphene oxide has been aminated successfully.The graphene/nanosilver composites were prepared by a one-step hydrothermal reduction method on the basis of aminodized graphene.The morphologies of the composites were characterized by transmission electron microscopy(TEM),scanning electron microscopy(SEM)and X-ray diffractometer(XRD),Raman spectra and pulse spectra.Structure and composition are analyzed.On the surface of composites,graphene has a unique fold structure and Ag nanoparticles are attached to graphene with folds.The average diameter of Ag nanoparticles is 10-20 nm and Ag nanoparticles increase the gap between graphene layers,which can prevent the agglomeration of graphene.The disappearance of(001)crystal plane diffraction peaks and the(111),(200),(220)and(311)crystal plane diffraction peaks in the product indicate the appearance of Ag nanoparticles in composites and their surface defects to graphene.Have a modification effect.The contents of O in GO,F2G,F4G,F6G and F8G were 34.33 wt%,16.67 wt%.16.21 wt%,16.17 wt%and 15.52 wt%,respectively,and the contents of Ag were 12.07 wt%,12.67 wt%,13.74 wt%and 15.46 wt%,respectively.The decrease of O element content and the increase of Ag element content indicate that GO and Ag+are simultaneously reduced to GE and Ag nanoparticles.The D and G peaks of GrO appear at 1331 cm-1 and 1598 cm-1,respectively.The R value is 1.05.The R value of the composite is 0.99.The R value of the graphene/nanosilver composites is smaller than the R value of GO,and the generated Ag nanoparticles functions to hinder agglomeration of the graphene sheet.From the silver mapping image,It can be seen that the Ag nanoparticles are uniformly distributed in the graphene/nanosilver composites,and the best dispersion of the Ag nanoparticles on the surface of the product is F8G.The working electrode was modified with graphene/nanosilver composites.The electrochemical response of the modified electrode in 6 mol/L KOH electrolyte solution was investigated by cyclic-voltammetry with the increase of scanning rate.The cyclic voltammogram curve is almost unchanged,alnd the current is kept in a constant range.The graphene/nanosilver composites have stable electrochemical properties.In addition,the electrochemical response of the modified electrode to copper,cadmium and mercury ions in water was studied by cyclic voltammetry.The graphene/nanosilver composites modified electrode has a good electrochemical response to Cu2+.The area of CV curve detected by the electrode has a good linear relationship with the logarithm of Cu2+ concentration.The curve fitting degree is 85.326%and the detection limit is 10-15 mol/L,so the detection limit of Cu2+obtained is more accurate,and the graphene/nanosilver composites modified electrode has a good electrochemical response to Cd2+and Hg2+.The linear relationship between the area of CV curve and the logarithm of Cd2+and Hg2+ concentration is poor.The fitting degree of the curve is 15.659%and 17.23%,and the detection limit is 10-21 mol/L and 10-29 mol/L,respectively.Therefore,the detection limits of Cd2+ and Hg2+ obtained are not accurate and are only estimated.Compared with FGO and F8G detection Cu2+ detection limit,F8G detection sensitivity preference can be obtained compared with FGO detection sensitivity preference,compared with FGO and F8G detection Cd2+and Hg2+detection limit,F8G detection sensitivity relative preference to FGO detection sensitivity can be obtained.