Construction And Application Of Functional AlOOH Composite SERS Substrate In Detection And Removal Of Organic Dyes

The pollution of the environment by organic dyes has caused widespread concern and their use in food has been banned in some countries,making their detection and removal essential.However,the serious toxicity of organic dyes,even at trace levels,has made the development of highly sensitive detection methods key to combating dye contamination.Surface-enhanced Raman spectroscopy（SERS）is an optical technique with high sensitivity for the detection of organic dye molecules.The realisation of highly sensitive SERS detection relies on the study of the enhancement mechanism and the construction of functional substrates.Based on the excellent performance of AlOOH functional materials,this thesis constructs a series of novel SERS substrates by modifying noble metals on AlOOH and explores their applications for highly sensitive SERS detection and contaminant removal.The research in this thesis is as follows:（1）A nanocomposite SERS substrate Au/AlOOH with both reactive and SERS-enhanced functions was designed and constructed to achieve highly sensitive detection of molecules such as rhodamine B（RB）.The SERS substrate utilises the three dimensions（3D）stable structure of AlOOH to achieve a homogeneous loading of Au,resulting in a SERS substrate that is both reactive and highly sensitive for detection.The OH group in the AlOOH structure is able to bind to Au,resulting in a strong interaction between the two,effectively improving the stability of Au and laying the foundation for the detection of the probe molecule.In addition,this material has excellent electrical conductivity,which facilitates carrier transport,improves charge utilisation and promotes catalytic reactions of molecules on the electrode surface.Moreover,the basic sites provided by the AlOOH are able to form an effective charge transfer（CT）with the analyte,further improving the sensitivity of the probe molecule in SERS detection.（2）An Ag/AlOOH nanocomposite SERS substrate with a porous structure was constructed by in situ reduction to enable the highly sensitive detection of molecules with affinity for OH groups.The Ag/AlOOH substrate has rich active site that can promote the probe molecules to be adsorbed on the surface of the complex,and the rich pore structure is conducive to the efficient adsorption of molecules on the complex,thus increasing the analyte concentration in the hot spot area of the SERS substrate.The AlOOH obtained in this chapter using a simple microemulsion synthesis method is rich in OH groups,allowing efficient loading of Ag and probe molecules.In addition,the OH groups on the Ag/AlOOH structure readily form hydrogen bonds with the probe molecules,allowing stable loading of the analyte onto the substrate surface.Therefore,based on the unique structure of Ag/AlOOH nanocomplex,highly sensitive SERS detection of probe molecules can be achieved,and this study is of great significance in the field of trace analysis and monitoring.（3）A porous structured SERS substrate,Ag NPs/AlOOH,was constructed by a co-blending method and explored for its application in SERS detection and contaminant removal.The Ag NPs/AlOOH substrate has good molecular adsorption for the detection of probe molecules such as rhodamine 6G（R6G）and crystalline violet（CV）,which can be used for contaminant removal,thus achieving integrated detection and removal.To further validate the potential of this complex for applications in environmental monitoring,monitoring and adsorption experiments were carried out in complex environments and the results showed that the constructed SERS substrate is fast,sensitive and somewhat resistant to interference.This versatile integrated SERS substrate provides a platform for the development of simple sensors that can be used for the detection and removal of contaminants in real environments.（4）A multifunctional AgNO₃/ANW composite substrate was constructed to achieve homogeneous loading of Ag⁺on the surface of AlOOH nanowires（ANW）,which not only accomplished highly sensitive detection of organic dye molecules,but also had excellent performance in the degradation of pollutants.The Raman enhancement achieved by functional AgNO₃/ANW substrate can be attributed to the fact that the high aspect ratio of ANW is beneficial to expand the distribution area of Ag⁺,resulting in a large number of hot spots in the active substrate.On the other hand,the increased number of anchor sites for adsorbed metal ions,based on the abundance of OH groups in ANW,can facilitate the interaction of ANW with metal ions,which in turn accelerates the charge and ion transport.In addition,this highly active nanowire array has a catalytic degradation effect on the dye molecule RB and is not affected by external conditions such as p H,which contributes to the removal of organic pollutants.The constructed multifunctional AgNO₃/ANW nanocomplex show great promise for practical applications,providing a reference for the detection and degradation of pollutants.