Study On Surface-Enhanced Raman Spectroscopy Of Furfural Dissolved In Transformer Oil Based On Ti₃C₂Tx And Silver Nanocomposite Substrate

The concentration of furfural in transformer oil is considered to be the key index that can reflect the aging degree of transformer.Therefore,the rapid and accurate detection and analysis of furfural is the key to accurately evaluate the aging state of transformer,which helps to eliminate the potential safety hazards caused by aging and ensure the stability of power system.However,the traditional furfural detection technologies such as high performance liquid chromatography,spectrophotometry and colorimetry have some defects,such as cumbersome operation,long detection cycle or easy to be disturbed.As a characterization technology that can analyze the substances adsorbed on the surface of noble metal nanostructures at the single molecule level,surface enhanced Raman scattering（SERS）technology has high sensitivity and the ability to obtain molecular fingerprint information without labeling.Moreover,this technology has the advantages of short detection cycle,not easy to be disturbed,simple operation and no cumbersome pretreatment process.It is an ideal detection method for dissolving furfural in oil.In the process of applying SERS technology,the preparation of substrates with excellent performance is the key to realize the ideal Raman enhancement effect.At present,the conventional substrate materials are mainly precious metal nanostructures.As a two-dimensional nano material,mxene has shown great application potential in the field of SERS because of its excellent physical and chemical properties.Therefore,the composite material composed of MXene and conventional metal nanostructures is expected to become an ideal SERS substrate.Therefore,the surface enhancement method of furfural Raman spectrum in transformer oil is deeply studied in this paper.The related work mainly includes:（1）Silver nanoparticles were obtained by sodium citrate reduction method,and then Ag NPs substrate was prepared.Ti₃C₂Tx/Ag NPs composite substrate was prepared by combining Ti₃C₂Tx MXene nanosheets with silver nanoparticles.The substrate was characterized by SEM and EDS.the results showed that the diameter of silver nanoparticles was about 50 nm and the particle size was relatively uniform as a whole.A large number of silver particles were distributed on the surface of Ti₃C₂Tx nanosheets on the composite substrate,and the two were combined to form a composite structure.The surface cleanliness of the two substrates is high and the content of impurities is less.The test results of R6G show that the lower detection limits of Ag NPs substrate and composite substrate can reach 10^-8mol/L and 10^-10mol/L respectively.（2）Silver nanowires were obtained by polyol method,and agnws substrate was prepared.Ti₃C₂Tx/Ag NWs composite substrate was prepared by combining Ti₃C₂Tx with silver nanowires.SEM showed that the diameter of silver nanowires on Ti₃C₂Tx/Ag NWs composite substrate was about 50 nm and the length was about 100μm.Ag NWs and Ti₃C₂Tx are uniformly combined.EDS results show that the substrate has high cleanliness and low impurity content.The test results of R6G show that the lower detection limits of agnws substrate and composite substrate can reach 10^-9mol/L and10^-10mol/L respectively.（3）Based on the SERS detection platform,we use R6G,Mg,furfural transformer oil and other reagents to test the performance of the substrate.The experimental results show that the composite substrate combined with Ti₃C₂Tx has better Raman enhancement effect than the silver nano material substrate.The composite substrate shows good surface uniformity,reproducibility and stability.The detection limits of furfural transformer oil solution on Ti₃C₂Tx/Ag NPs composite substrate and Ti₃C₂Tx/Ag NWs composite substrate can reach 63.4 mg/L and 54.4 mg/L respectively;The detection limits of furfural aqueous solution can reach 75 mg/L and 62.5 mg/L respectively.The least square method was used to regress the Raman characteristic peak intensity of furfural molecule and its corresponding concentration.The results showed that they had a good linear relationship.To sum up,in this paper,the two-dimensional material Ti₃C₂Tx MXene was combined with the traditional silver nanostructure to form a composite material.SERS substrates with different structures and morphologies were prepared,characterized and tested.After comparison,the composite substrate with Ti₃C₂Tx has better SERS performance.The detection results of furfural transformer oil and furfural aqueous solution show that it is feasible to realize the quantitative analysis of furfural by using the composite substrate combined with Ti₃C₂Tx and silver nano materials based on SERS technology.The study of this paper provides a new idea for the surface enhancement method of Raman spectrum of furfural in transformer oil.