Preparation Of Nano Copper/silver Graphene Composites And Electrochemical Properties Of Modified Electrodes

Graphene has been used as an excellent carrier for metal nanomaterials due to its unique structure and physical and chemical properties.Metal nanoparticles are often used to construct electrochemical sensors because of their special catalytic activity.The introduction of metal nanoparticles into graphene can effectively leverage the unique advantages of these two materials,which are receiving increasing attention in the field of sensing.In this paper,nano copper/silver graphene composites modified glassy carbon electrodes were prepared by electroless plating and surface accumulation coating method.Their properties were characterized by modern material characterization techniques such as XRD,EDS,XPS,SEM,FTIR and electrochemical methods such as CV,EIS,LSV,and applied to the detection of hydrogen peroxide and phenol.The research content mainly includes the following aspects:Nano-cop-graphene composites(Cu/GR)were prepared at 40℃ with glucose complex hydrazine hydrate as reducing agent,succinic acid as stabilizing agent,malic acid and sodium tartrate as complexing agent in graphene cupramine mixture.Cu/GR composites were modified on the surface of GCE by surface aggregation coating method to prepare electrochemical sensors for Cu/GR/GCE detection with high selectivity of H2O2.The electrochemical behavior of H2O2 on Cu/GR/GCE was investigated by electrochemical test.The results show that the CuNPs in Cu/GR are Cu0,spherical and uniformly loaded on the surface of GR,with an average grain size of about 23 nm.When Cu/GR/GCE is used as the working electrode,the peak oxidation current is 307.4μA,the peak reduction current is 252μA,and the minimum Rct value is 70.08Ω,which is beneficial to the electron transfer process.The order of accelerating electron transfer is Cu/GR/GCE>GR/GCE>CuNPs/GCE>Naked GCE.The parameters of H2O2 detection were optimized,and the effects of scanning interval and buffer pH value on the reaction were studied.The optimal scanning interval was-1V～0V,and the optimal pH of buffer solution was 5.0.Then,the electrochemical behavior of H2O2 in 9 different buffer solutions was investigated,and it was found that 0.2 mol/L HAcNaAc was the best.Finally,the scanning rate is investigated,and the best scanning rate is 100 mV/s.Nanoscale silver-graphene composites(Ag/GR)were prepared at 40℃ with glucose complex hydrazine hydrate at low concentration as reducing agent,succinic acid as stabilizing agent,malic acid and sodium tartrate as complexing agent ingraphene silver ammonia mixture.The graphene nano silver sensor was prepared by drip coating method.The effective electrode area was 30.73 cm2 and the impedance was about 75 Q.The modified electrode has obvious catalytic activity for phenol,and the reaction of phenol on the electrode is mainly a quasi-reversible process controlled by diffusion.The detection of phenol by the sensor shows a wide linear range of 10μM-320μM,which is divided into low concentration range of 0μM-50μM and high concentration range of 50μM-320μM.The reduction peak current of low and high concentration is linear with the concentration,and the regression equation of low concentration is:Ip=0.2209c+54.07,R2=0.986.The detection limit LOD is 24μM,and the sensor has good stability and selectivity.