Preparation And Application Of SERS Substrates Based On Anodized Alumina

In recent years,Surface-Enhanced Raman Spectroscopy(SERS)has attracted widespread attention due to its unique advantages,such as strong specificity,high sensitivity and nondestructive detection.However,among various types of SERS substrates,three-dimensional SERS substrates attracted the attention of scientists due to their larger specific surface area,more hot spot capacity and higher laser utilization rate.Three-dimensional SERS substrate has been applied in pollutant detection,biological detection and other aspects,among which Anodized Aluminum Oxide(AAO)not only has all the advantages of the above three-dimensional substrates,but also has a fast and simple preparation process,regularized structure hole array with adjustable scale and has been widely studied.This thesis summarizes the main types and characteristics of SERS substrates based on AAO in these years,and explores its application in pollutant detection and biomedical analysis.The main research contents are as follows:(1)In order to study the practical application of AAO in sewage detection,a composite structure composed of AAO,Ag and molybdenum disulfide was designed and prepared.Molybdenum disulfide,as the interlayer of AAO and Ag nanoparticles,not only provides excellent chemical enhancement effect for the substrate,but also can be used as the internal standard of the substrate to achieve fine quantification of detected molecules.By adjusting the coverage area of Ag nanoparticles,the structure can generate both surface hot spots near the side wall and volume hot spots in the cavity.The structure successfully enables the detection of water contaminants at a wide range of sizes from angstrom to hundreds of nanometers,including mercury ions,4-aminothiophene,and polystyrene nanoplastics(nanoplastics with diameters of 100 nm,200 nm,and 300nm).This is the first strategy to integrate pollutant detection of various sizes into a SERS substrate.This work proposed a common SERS strategy for detecting water pollutants of various sizes,which is expected to be used in the early warning system to prevent water pollution and establish a healthy and safe defense line.(2)In order to further expand the SERS application of AAO,in addition to detecting conventional solid-state molecules,we designed and discussed a composite AAO/Ag/ZIF-8 threedimensional composite structure.The structure integrates ZIF-8 particles with high adsorption properties and Ag nanoparticles in the AAO cavity,and collects gas molecules in ZIF-8 by the enrichment of ZIF-8.Through the synergistic effect of surface hot spot on the side wall and volume hot spot in the cavity,the gas molecules can be detected which are difficult to capture.This structure overcomes the drawback that the conventional SERS substrate is difficult to detect gas molecules,and expands the further application of the SERS substrate based on AAO,realizing the non-invasive detection and identification of diseases by detecting human exhaled gas molecules.