Surface Treatment Of Silver-based Materials And Its Application In Analysis

Silver metal materials have excellent physical and chemical properties,such as high electrical conductivity,thermal conductivity,stability,and unique electrical and photochemical properties.Since metallic silver is relatively expensive,it has mainly acted as a monetary and financial role in history.With the continuous development of industry and modern science,its technological attributes are getting higher and higher,and metallic silver plays an important role as a functional material for modern industry and high-tech industry.In this paper,the metallic silver material is selected as the research object,and the surface of the silver material is treated with different processing methods to obtain the silver surface treatment material we need.The surface-treated silver material was used as the base material and electrode material in analytical chemistry.The trace hydrogen peroxide was electrochemically analyzed,and the p-phenylenediamine?PPD?was subjected to SERS analysis.The specific research content is as follows:1.First,the alloying/electrochemical dealloying method is used to change the properties of the surface of the silver material.During the alloying process,we apply the liquid metal gallium uniformly on the surface of the smooth silver,and then put it in a drying oven at a constant temperature of 100?.After heating for 3 hours,the Ag-Ga alloy compound is obtained,and then the Ag-Ga alloy sample is placed in a 1 mol/L NaOH solution to electrochemically remove the metal Ga in the Ag-Ga alloy compound,thereby obtaining a nanoparticle silver layer.2.The alloying/electrochemical dealloying method is used to change the characteristics of the surface of the silver material.In the XRD pattern,the nanoparticle silver layer prepared by the alloying/electrochemical dealloying method has only a diffraction peak with a diffraction angle 2?of 77.42°.It corresponds to the?311?diffraction plane of the silver crystal,which indicates that the nano silver layer obtained by alloying/dealloying has a characteristic of preferential orientation along the direction of the crystal plane?220?.In addition,according to the Scherrer equation,the average grain size of the prepared nanoparticle silver layer is 70 nm.In the SEM spectrum,the results show that the surface particle size of the nanoparticle silver layer sample is 50-100 nm.3.The prepared nanoparticle silver layer electrode and smooth silver electrode were used as research electrode respectively.The results of cyclic voltammetry in 1.0 mol/L NaOH solution showed that the first anode current peak of the cyclic voltammetry curve of the nanoparticle silver layer electrode was the peak generated by Ag₂O is generated electrochemically,and its position is at a potential of 800mV,where the peak current density is 165mA/cm²,which is 22times the current density of the corresponding position of smooth silver.During the cathode reaction,there is a cathode peak,which is formed by the electrochemical reduction of Ag₂O to Ag,its position is at a potential of 450 mV,and its peak current density is 188 mA/cm²,which is10 times the current density of the corresponding position of smooth silver.4.The nanoparticle silver layer prepared by the alloying/electrochemical dealloying method was used as the SERS matrix,and SERS tests were performed on different concentrations of p-phenylenediamine?PPD?.The results show that the SERS intensity increases with increasing PPD concentration,the intensity of the Raman peak is linearly related to the logarithm of the PPD concentration,the linear correlation coefficient R value is 0.99,and the PPD concentration range is 1×10^-1616 mol/L to 1×10^-1212 mol/L.5.The surface of the silver material was modified by electrodeposition,and a layer of silver was electrochemically deposited on the silver sheet.A smooth silver sheet was used as the research electrode,a smooth silver sheet was used as the auxiliary and reference electrode,and a0.1 mol/L AgBF₄ solution was used as the electrolyte.The research electrode was electrodeposited at a current density of 10 mA/cm² to obtain a silver material with a layer of functional silver on the surface.6.The electrodeposition method is used to modify the surface of the silver material,and the electrodeposited silver layer is obtained after the modification.In its XRD pattern,the electrodeposited silver layer prepared by the electrodeposition method has a diffraction peak at the same position as smooth silver,but the intensity of the diffraction peak is different.The strongest characteristic peaks of the electrodeposited silver layer and the smooth silver sheet are located at 38.11°and 64.43°,respectively,corresponding to the?111?and?220?diffraction planes of the silver crystal,which indicates that the electrodeposited silver layer prepared by electrodeposition the feature of preferential orientation in the direction of the crystal plane?111?.According to the Scherrer equation,the average grain size of the electrodeposited silver layer is calculated to be 20?m.In the SEM spectrum,the results show that the surface particle size of the electrodeposited silver layer sample is 10-30?m.7.Using the prepared electrodeposited silver layer as the research electrode,the cyclic voltammetry study in 1.0 mol/L NaOH solution showed that the prepared electrodeposited silver layer electrode had the first anode peak?Ag₂O peak formed electrochemically,peak potential380 mV vs Hg/HgO?The peak current density is 5 mA/cm²,which is 2.5 times the peak current density of the smooth silver electrode here.During the cathodic reaction,the peak current density at the peak potential of 450 mV?Ag₂O electrochemical reduction to Ag?peak current density is 7.2 mA/cm²,which is twice the reduction peak current density corresponding to the smooth silver electrode.8.The electrodeposited silver layer prepared by the electrodeposition method as a research electrode,cyclic voltammetry tests were performed on hydrogen peroxide?H₂O₂?with different concentrations.The results showed that the peak current density of the cyclic voltammetry curve increased with the concentration of hydrogen peroxide However,the concentration of H₂O₂ranges from 1×10^-6mol/L to 50×10^-6mol/L.The peak current density is linearly related to the concentration of H₂O₂,and the linear correlation coefficient R value is 0.995.