The Synthesis Of Nanometer Silver And Application In Electrochemical Sensors

With the rapid development of science and technology,sensor technology has been rapidly developed.Sensors were closely related to human life and were applied in many fields such as environmental monitoring,food safety and clinical medicine.Among them,because the electrochemical sensor is suitable for the detection of various fields,it has become the focus of many researchers.Various kinds of electrochemical sensors have been studied,so it is of great practical significance to design excellent electrochemical sensors and apply them to various fields of human life.In order to meet the needs of present hot spot detection,therefore,from the study of electrochemical sensor sensing mechanism,we were committed to the material synthesis and performance optimization,the sense applied to heavy metal ion,glucose,hydrogen peroxide and a variety of electrochemical sensor detection was built.The sensing mechanism,sensing performance and sensitive characteristics of the above sensors were studied systematically.It was divided into the following three contents:(1)Aiming at the problem of detecting harmful substances in environmental pollution,the idea of sensor of heavy metal ions detection was proposed.Silver dendrites were fabricated on platinum mesh by electro-deposition in pure Ag NO₃solution.The dendritic silver powders with nano-branches were obtained after the platinum mesh treated by ultrasonic process.Firstly,it was characterized by field emission scanning electron microscopy(FE-SEM)and X-ray diffraction(XRD).Then,the modified electrode was modified to the surface of glassy carbon electrode,and the electrochemical performance of the modified electrode was characterized by frequency impedance scanning(EIS)and linear cyclic voltammetry(CV).Then,Heavy metal ions were detected by square wave anodic stripping voltammetry(SWASV)and differential pulse voltammetry(DPV).The SWASV method was used to detect cadmium(Cd(II)),lead(Pb(II)),copper(Cu(II)),mercury(Hg(II))in concentration range 0.05?mol·L^-1?0.45?mol·L^-1,the detection limit were 0.145?mol·L^-1?0.104?mol·L^-1?0.115?mol·L^-1?0.087?mol·L^-1,respectively.Finally,the stability of the electrode material was further demonstrated.Nano-dendrite silver can be used as one of the potential materials for the detection of heavy metal ions.(2)Various functions of nano-silver were widely applied.In order to study the other detection application of dendrite nano-silver,the deposition conditions were changed.Dendritic silver nanoparticles were deposited at copper network in a single Ag NO₃solution.Firstly,the structure morphology of the synthesized nano-dendrite silver was characterized by field emission scanning electron microscope(FE-SEM).Then the further electrochemical characteristics were analyzed by cyclic voltammetry(CV)and electrochemical impedance spectroscopy(EIS),the experimental results show that the dendritic nano-silver has excellent electrochemical properties.Then,the synthetic material were used to modify glassy carbon electrode for glucose detection by chronocurrent method,and the detection limit was 3.0×10^-7mol·L^-1.The detection limit of the non-enzymatic glucose sensor has reached the same level of glucose detection at home and abroad,and non-enzymatic glucose sensor has low detection limit,simple preparation and low cost,which shows a promising application prospect.(3)In order to study the difference of detection results when the same substance was detected by silver nanoparticles with different morphologies,silver nanowires(Ag NWs)and rough silver nanowires(M-R Ag NWs)similar to massage shafts were prepared by polyol reduction method,and their morphology and structure were characterized by FE-SEM.For further electrochemical characterization,the two synthesized substances(Ag NWs and(M-R Ag NWs)were used to modified the glassy carbon electrode(GCE)surface by CV and EIS in a three-electrode system.The CV test results were showed two kinds of morphology of silver nanowires had good electrochemical properties for glucose and hydrogen peroxide,and the chronoamperometry was used to detect glucose and hydrogen peroxide(H₂O₂),electrochemical,M-R Ag NWs show better catalytic properties for glucose and H₂O₂detection,The electrochemical results represented that detection limit of M-R Ag NWs for hydrogen peroxide and glucose were 0.3?mol·L^-1and 0.18?mol·L^-1,respectively.The selectivity were 4.68 m A·m M^-1·cm^-2and 4.22 m A·m M^-1·cm^-2,respectively.Moreover,anti-interference detection was carried out by the M-R Ag NWs,the influence of the interferent was negligible in the detection process.