Fabrication Of Metal-organic Frameworks On The Surface Of Silver Foil And Their Applications In SERS Monitoring On Photocatalytic And Electrocatalytic Systems

Surface-enhanced Raman scattering（SERS）is a vibrational spectroscopy which can characterize the structure of molecular adsorbed on the surface of the substrate material with extremely high detection sensitivity and selectivity.Therefore,it can be applied to the catalytic system to monitor the changes of the reaction system in situ and detect the products and intermediates of the catalytic system.This is very meaningful for understanding the structure-activity relationship and reaction mechanism of catalysts in catalytic systems at the single-molecule level.To link the catalytic system with SERS technology,it is first and foremost to construct a substrate material with good SERS properties and catalytic properties.Combining SERS characteristic with good catalytic properties on the substrate material which can provide broader possibilities for the application of SERS in the field of catalysis.Metal-organic frameworks（MOFs）are a kind of organic-inorganic hybrid porous materials which centered on metals or metal clusters through the coordination and bonding of organic bridging ligands.In recent years,SERS substrate combining with MOFs has attracted extensive attention.The substrate materials composited with MOFs can not only obtain some excellent properties of MOFs,such as molecular enrichment ability,catalytic selectivity,etc.,but also can improve the transmission and sensory performance of traditional SERS substrates.In this part of the work,two kinds of MOFs/Ag substrate materials,MIL-100（Fe）/Ag and Fe-TCPP MOF/Ag were constructed by metal-organic frameworks self-assembly on the surface of Ag foil.MIL-100（Fe）/Agwas used in the SERS monitoring on degrading organic pollutants and pharmaceutical pollutant.Fe-TCPP MOF/Ag were used in the in-situ SERS analysis system for electrocatalytic reduction of CO₂.And the two reaction mechanisms were further studied.The main research contents of this paper are as follows:a)The construction of MIL-100（Fe）on the surface of silver foil and their applications in SERS detection and monitoring on photocatalytic degradation of drug contaminantsIn this work,the MIL-100（Fe）/Ag SERS substrate material was functionalized by substitution reaction and epitaxial growth and then constructed by layer by layer assembly method of Fe³⁺and pyromellitic acid（H₃BTC）on the surface of silver foil.The structure maks it great adsorption performance which can absord the pollutants in the environment.Furthermore,the MIL-100（Fe）/Ag has excellent photocatalytic ability to degrade organic pollutants and drugs.And the catalytic degradation reaction process is monitored by its good SERS properties.This work in SERS application field provides a meaningful research reference.b)The construction of Fe-TCPP MOF on the surface of silver foil and their applications in SERS monitoring on electrocatalytic reduction of CO₂systemsFe-TCPP MOF/Ag was successfully prepared by hydrothermal method and displacement method using Ag foil as raw material,realizing the uniformity growing of Fe-TCPP MOF on the surface of Ag foil.Due to the coating of MOFs,the surface of the complex has a porous structure,which can capture the CO₂molecular,and the porphyrin iron complexed in the center of the Fe-TCPP MOF ligand also has a good affinity for CO₂molecular.Therefore it can act as a good catalyst for the carbon dioxide electrocatalytic reduction reaction.The porous structure on the surface of Ag foil gives it more SERS active hot spots,which makes it have good SERS properties,and the material is self-supporting which makes it can be directly used as an electrode in the electrolytic cell.In summary,the combined of in-situ SERS and electrocatalysis can realize the monitoring of the entire reaction.This work provides new ideas for the design of the multifunctional SERS substrate and its application in the in-situ SERS monitoring the electrocatalysis system.