Preparation Of Eggshell Membrane Supported Functional Composite Nanomaterials And Their Performance In SERS And Catalytic

Combined with the properties of two or more materials,functional composite nanomaterials can greatly broaden their application in many research areas.Combining the natural biomass with nanomaterials is the tendency for developing new types of materials.As for its properties of“green”,low-cost and environmental friendly,it will be worthy of our in-depth study.As a rich resource,low-cost,natural green material,eggshell membrane（ESM）has aroused widespread concern.In addition,the ESMs showed excellent application prospects in environmental pollution,biosensing,biomedical and other aspects due to the porous fibrous structure and the active composition.In this paper,we are aimed to prepare two types of functional composites by integrating the pristine eggshell membrane with nanomaterials through self-assembly method.Furthermore,the composites will be used to in the field of catalytic reaction and Surface Enhanced Raman Scattering（SERS）.The specific research contents are as follows:（1）The preparation of eggshell membrane with triangle/discal silver nanoparticles composite film and its SERS analysisBased on the combination of natural eggshell membrane and anisotropic silver nanoparticles,a novel SERS substrate material was prepared.The triangular silver nanoparticles were synthesized at room temperature.Because of its localized surface plasmon resonance（LSPR）optical property,the color of Ag colloidal is blue.The AgNP@ESM composite membrane material was fabricated by electrostatic interaction,and then the method of thermal aging was used to convert the triangular silver nanoparticles into the discal silver nanoparticles.The changes of the morphology and size of the silver nanoparticles resulted in the nature of the LSPR change,the color of eggshell membrane changes from blue to yellow in visual,which directly leads to the signals of reporter molecule absorbed on the substrate material with different SERS enhancement effects.（2）The fabrication of eggshell membrane and silver triangle nanoparticle composite membrane and its performance in catalytic and SERSAs a bioscaffold,the porous eggshell membrane can load with Ag nanoprism via an electrostatic self-assembly approach.The LSPR property of silver nanoprism leads to the blue color of the treated eggshell membranes.UV-Vis diffuse reflectance spectroscopy,scanning electron microscope（SEM）,X-ray diffraction（XRD）and X-ray photoelectron spectroscopy（XPS）measurements were employed to observe the microstructure and surface property of Ag nanoprisms on the eggshell membranes.The results show that the three-dimensional porous structure of eggshell membrane do not change after treating with Ag nanoprism.The silver nanoprism-loaded eggshell membrane exhibited strong catalytic activity for the reduction of4-nitrophenol by sodium borohydride（NaBH4）and it can be easily recovered from the reaction system and reused for more than six cycles.Significantly,the composites also display excellent SERS efficiency,allowing the in situ SERS monitoring of molecular transformation in heterogeneous catalysis.（3）The preparation of eggshell membrane and titanium dioxide nanoparticles composite films and its performance in photocatalyticTitanium dioxide,as a photocatalyst with properties of non-toxic,low-cost,excellent stability and biocompatibility,was combined with a green platform with three-dimensional porous structure（eggshell membrane）,so as to the combination the advantages of two.The eggshell membrane,a natural biosorbent,can adsorb the organic dye.Furtherly,with the assistant of titanium dioxide with the excellent photodegradation property,the low-cost composite catalyst materials can be fabricated which can rapidly degrade organic dyes and for reuse.The microstructure of TiO₂ nanoparticles absorbed on the membrane fibers was studied by UV-Vis,SEM,XPS,TGA,XRD and Raman measurements.The results indicate that a large amount of titanium dioxide nanoparticles were successfully assembled on the fiber membrane.The composite film was used for the photodegradation of Rhodamine B（RhB）dye molecules.The results also indicate that the composite catalyst can show good photocatalytic activity for dye degradation.