SERS Properties And Plasmon Catalytic Reactiom Of Single Particle Ag And Ag@Go Microspheres

Since the initial discovery of the SERS technology,research on SERS substrates has focused on precious metals and the substrates are aggregated.The laser energy distribution of the microscopic confocal Raman spectrometer is Gaussian distribution,and generally the diameter of the spot is much smaller than the diameter of the aggregates,which leads to the measured Raman signal is susceptible to environmental interference outside the spot on the substrate,so that there is some error in the test results.Due to the high cost of precious metal substrates and the advantages of two-dimensional materials with large specific surface area and high electron mobility,researchers have shifted the focus of research on substrate materials to the composite of precious metals and twodimensional materials.In this project,two single-particle silver substrates have been prepared for correlation studies: single-particle Ag microspheres with abundant secondary structures and single-particle Ag@GO microspheres compounded with silver and monolayer graphene oxide.In this paper,Ag microspheres and Ag@GO microspheres were prepared by reduction method.The morphology and particle size of the microspheres were controlled by adjusting the amino acid species,reactant concentration,and reaction temperature.The morphology was observed using SEM,the crystal shape was determined using XRD,and the thickness of Ag microspheres coated with graphene oxide was determined using Raman.In the first part of this project,L-alanine,L-cysteine and L-phenylalanine were used to induce the preparation of single-particle Ag microspheres,and the SERS performance test and plasmon catalytic reaction were carried out on this basis.the study.The detection limits of the dye molecules CV and R6 G for the three single-particle Ag microsphere substrates were 10^-6 mol/L,but the SERS performance of the single-particle silver microspheres induced by L-cysteine was the best.Polycyclic aromatic hydrocarbons were detected on the basis of Ag microspheres with the best performance,and it was found that the substrate could not detect PYR molecules,and the detection limit of B?a?P molecules was 10^-4 mol/L.The plasmon catalytic reactions of 4-ATP and 4-NTP molecules can occur on single-particle Ag microsphere substrates induced by three different amino acids,and the catalytic efficiency comparison at the same time under the same test parameters found that L-Cysteine-induced silver microspheres have the highest catalytic efficiency.The work in the second part was improved on the basis of the work in the first part,and single particle Ag@GO microspheres were prepared.The detection limit of the substrate for dye molecules CV and R6 G is 10^-7 mol/L;the detection limit for polycyclic aromatic hydrocarbons PYR is about 10^-4 mol/L,and the detection limit for B?a?P is 10^-5 mol/L.There is no plasmon catalysis reaction on graphene oxide,and there is no plasmon catalysis reaction related to 2-ATP and 3-ATP molecules on the single particle Ag@GO microsphere substrate,but 4-ATP and The plasmon of 4-NTP catalyzes the reaction,and the reaction efficiency is positively correlated with the laser power.In addition,the present study has demonstrated that the substrates are relatively homogeneous,which provides the feasibility of practical applications of such substrates.