Preparation,Modification And Application Of Gold And Silver Nano-sized Electrodes

In recent years,nanoelectrodes are widely used in field of electrochemical research due to their advantages of small charging current,fast transfer rate and smaller solution resistence,such as the study of electron transfer kinetics,high resolution imaging in Scanning Electron Microscopy（SECM）and single nanoparticle.Among the metal nanoparticles,gold,platinum and silver nanoparticles have been widely studied in bioanalysis and electrocatalysis due to their unique properties,but the study of nanoparticles will be affected by many factors such as particle aggregation,particle morphology and supporting materials.Therefore,investigation of nanomaterials at single particles level by using single gold/silver nanoelectrodes was necessary.Herein,single gold/silver nanoelectrodes were prepared by laser pulling technique,and the prepared electrodes were investigated by electrochemical method.The nanoelectrodes were used for the catalysis of methanol and the detection of glutathione.The paper mainly includes four aspects:Chapter 1:Research progress in nano-sized electrodes.Chapter 2:Preparation of single Sliver nanoelectrode and study on their size voltammetric effect.Single silver nanoelectrodes with a radius as low as 10 nm were obtained by laser-assisted pulling technique,and characterized by field emission scanning electrochemical microscopy（SEM）,field emission transmission electron microscopy（TEM）and X-ray energy spectroscopy（EDS）.Electrochemical methods were used to study the size response of single silver nanoelectrodes.Chapter 3:Preparation and Catalytic CH₃CHOH Performance of Silver Palladium Alloy Nanoelectrodes.On the basis of the preparation of the single silver nanoelectrode,a silver-palladium alloy nanoelectrode was prepared by metal displacement.The electrocatalytic performance of methanol was investigated by the prepared alloy nanoelectrode,and compared with commercial Pd/C for methanol catalytic performance,showing good catalytic activity and stability.Chapter 4:Preparation and application of glutathione（GSH）nanosensor.The GSH nanosensor was constructed by Au-S using a gold nanodisk electrode as a substrate.Ag nanoparticles and methylene blue were used as electrochemical detection signals,and GSH was detected by differential-pulse voltammetry.This method has demonstrated a high sensitivity of GSH detection with the concentration range from 10nM to 1uM and a detection limit of 0.9nM.