Research On The Preparation And Analytical Application Of Functionalized Gold And Silver Nanomaterials

Nanomaterials refer to the materials whose one or more external dimensions issized between 1 to 100 nm.Compared with macroscopic materials,nanomaterials have some excellent properties,such as quantum size effect,surface effect,small size effect and macroscopic quantum tunneling effect.which have attracted great attention from researchers.Among them,the noble metal nanomaterials,such as gold,platinum and silver nanomaterials,have been widely used in biosensing,electrochemical catalysis,cell imaging,disease diagnosis and other aspects due to their large specific surface area,good electrical conductivity,excellent interface effect and small size effect and some special properties.In order to further improve the properties of noble metal nanomaterials and expand their application range,many chemical or physical methods are used to functionalize metallic nanomaterials.The main purpose of this paper is to explore a simple and feasible functionalization method of noble metal nanomaterials in order to prepare noble metal nanomaterials with excellent analytical properties.Based on this,this paper mainly contains two parts of the review and research report:The first part is the review part of the paper.Firstly,the properties,synthesis methods and characterization methods of noble metal nanomaterials,especially gold nanorods and silver nanoparticles,are briefly introduced.Secondly,the functionalization methods of gold nanorods and silver nanoparticles are introduced.And some of its main applications in analytical chemistry;finally,combined with these research backgrounds,the research ideas and significance of this paper are proposed.The second part of this thesis is the research report,which is mainly composed of the following two parts:1.Voltammetric method for sensing pH value of strong basic solution based on Ag3PO4shell@Ag core nanoparticles modified Au electrodeIn this work,silver nanoparticles were modified on the gold electrode by electrodeposition.When the modified electrode was scanned in phosphate buffer solution by cyclic voltammetry,a pair of redox peaks appeared,and the reduction peak potential was positively shifted with the decrease of pH.In this paper,SEM characterization and cyclic voltammetry were used to investigate the electroactive substances corresponding to this redox peak.The results showed that during the cyclic voltammetry scanning of the modified electrode in the phosphate solution,the silver elements on the surface of the silver nanoparticles were oxidized into silver ions,and the silver ions and the high concentration of phosphate ions in the solution form silver phosphate on the surface of the silver nanoparticles.Silver phosphate as an electroactive substance undergoes subsequent redox reaction.In addition,the reduction peak potential of the modified electrode in phosphate buffer solution has a linear relationship with the pH value in the range of 10-14.The slope of the linear relationship is basically consistent with the slope of the relationship between the reduction peak potential of the electroactive substance and the pH value derived from Nernst Equation.Based on this,we constructed a method to determine the pH value of strong alkali solution by Ag nanoparticle modified electrode functionalized with silver phosphate.This method breaks through the alkaline upper limit of pH glass electrode to determine the pH value of solution,and it is easy to operate without expensive reagents.2.Study on the stability and analytical properties of gold nanorodsfunctionalized by CTABIn this paper,the gold nanorods with good dispersibility were prepared by seed synthesis method,and separated from the mother liquor by centrifugation to obtain gold nanorods.Then,the gold nanorods were washed with different concentrations of CTAB solution,dispersed in the same volume of ultrapure water,and the UV-visible absorption spectrum of the obtained gold nanorod dispersion was determined.The results showed that the position of the maximum absorption peak of the gold nanorods washed with different concentrations of CTAB solution remained unchanged,but the absorbance at the maximum absorption wavelength increased with the increase of the concentration of CTAB.In this paper,the interaction between CTAB and gold nanorods and its effect on the stability of gold nanorods were investigated by UV-visible absorption method and extraction method.Based on this,a simple and rapid method for the determination of CTAB by UV-visible absorption spectroscopy was established.