Construction Of Plasmon Materials And Their Application In The Detection Of Trace Pollutants In Wate

Under the irradiation of light at specific wavelengths,plasmonic materials undergo Localized Surface Plasmon Resonance（LSPR）,leading to the formation of an intense electromagnetic field near the surfaces of these materials.This phenomenon is accompanied by the generation of photo-induced charge carriers（electron-hole pairs）and the occurrence of photothermal effects.Such characteristics enable the conversion of light energy into various forms,including chemical,thermal,and electromagnetic energy,thus holding significant implications for research in optical sensing,photocatalysis,and solar cells.The LSPR effect of plasmonic materials is highly susceptible to factors such as morphology,size,and composition.To maximize the utilization of the LSPR effect,meticulous control and optimization of morphology and composition of plasmonic materials are necessary.This allows for effective and precise control of the LSPR effect to meet the differentiated demands for material performance in various application domains.Water pollution has become increasingly severe due to improper treatment and discharge of wastewater in productive and daily life,now is recognized as the primary threat to human health.Chemical pollutants typically exist in water bodies at low concentrations,posing potential risks to human health upon prolonged exposure.Therefore,the development of rapid,sensitive water pollution detecting techniques,and the advancement of environmentally friendly and efficient pollutant treatment methods are crucial for protecting water resources,maintaining ecological balance,and achieving sustainable development.Research indicates that the LSPR effect of plasmonic materials not only enhances the sensitivity of spectral detection but also improves the light absorption capacity and light conversion efficiency of photoactive materials,offering new avenues for addressing environmental pollution and energy crises.Benefiting from the enhanced effects of LSPR,surface-enhanced Raman scattering（SERS）spectroscopy,photoelectrochemical（PEC）,and photocatalytic technologies demonstrate significant potential in the fields of environmental detection and remediation.This thesis,based on the demand for detecting corresponding chemical pollutants in aquatic systems,utilizes the LSPR effect to construct a series of plasmonic materials.Through SERS and PEC sensing technologies,high-sensitivity detection of trace pollutants in water is achieved.Additionally,attempts are made to combine photocatalytic technology to achieve self-cleaning and reusable materials.The study also explores the sensitivity enhancement mechanism of plasmonic materials and optimization strategies for detection methods,providing valuable references for further improving the performance of analytical detection techniques and expanding the application research of plasmonic materials.The specific research topics covered in this thesis are summarized as follows:（1）Constructing a self-assembled monolayer gold film and achieving highly sensitive detection of plasticizers using SERS technologyA monolayer plasmonic array of gold nanoparticles（Au NPs）was successfully prepared through the self-assembly technique at the liquid-liquid interface.Under the effect of hydrophobic functionalized ligand 1-dodecanethiol,numerous hot spots were distributed on the SERS substrate surface of the prepared Au NPs monolayer film,and BBP could be enriched to the substrate surface through hydrophobic interaction,facilitating the trace detection of butyl benzyl phthalate（BBP）.Within the concentration range of 10^-8 to 10^-5 mol/L,the characteristic SERS response intensity of BBP exhibited a good linear relationship with its concentration,with the lowest detection limit of 2.70×10^-9 mol/L.This method has been successfully applied to the evaluation of plasticizer migration in plastics and can be used as a potential tool for rapid analysis of plasticizers.（2）Using Au/ITO as the SERS substrate and optimizing internal standards to enhance the sensitivity and accuracy of nitrite detection via ratiometric analysis methodBased on the specific azo reaction between p ATP and nitrite in acidic media,p ATP/Au/ITO SERS chip with stable hot spot distribution was prepared to detect the nitrite in the lake by ratiometric SERS method.At the same time,according to the molecular structure changes during p ATP azo reaction and SERS surface selection law,the internal standard selection was reasonably optimized,which increased the detection sensitivity of nitrite by about 10 times compared with the traditional method.The internal standard optimization criterion proposed in this work greatly improved the detection sensitivity and accuracy of the ratiometric SERS assay.Also,it provided an important selection basis for ensuring the robustness of the ratio quantitative method.（3）Constructing ITO/Au/Cu₂O electrode and achieving PEC quantitative detection of paraquat in waterThe synergistic effect between the LSPR effect of Au nanoparticles and the Schottky junction of Au/Cu₂O significantly enhances the photoelectrical performance of ITO/Au/Cu₂O,which can be used for sensitive PEC detection of highly toxic pesticide paraquat in water.Through the optical and electrochemical characterization of the composites,it is proved that the introduction of Au not only suppresses the self-photoreducing corrosion of Cu₂O,but also enhances the composite material’s light absorption capacity and the separation efficiency of photo-induced charge carriers.At the same time,it provides a reference for exploring the mechanism of synergistic enhancement of plasmon semiconductor composites such as precious metals.The method shows good anti-interference ability and reliability in real sample detection and also provides a new method for detecting paraquat residues in environmental water.（4）Constructing an integrated platform based on MXene/g-C₃N₄ composite films for the detection,adsorption,and degradation of crystal violet in waterBased on the LSPR effect of MXene and the energy band matching between MXene and g-C₃N₄,MXene/g-C₃N₄ composite material with excellent SERS enhanced effect and good photocatalytic activity was prepared for the detection and photodegradation of crystal violet（CV）in water.Benefiting from the flexible characteristics of MXene,the composite material can be prepared into a film.The prepared composite membrane material exhibits excellent filtration effect and photocatalytic self-cleaning ability,which can not only perform highly sensitive SERS detection of CV,but also realize rapid removal of CV in water and reuse of membrane material,providing a comprehensive solution for monitoring and treatment of pollutants in environmental water.