Research On Preparation And Application Of MXene-based Low-dimensional Materials

The unique physical and chemical properties of MXene-based low-dimensional materials have attracted great attention from researchers.Among them,two-dimensional MXene nanosheets integrate metal conductivity,hydrophilicity,flexibility and rich surface chemistry,and have great potential in many fields.MXene quantum dots have a wealth of active catalytic sites,excellent optical properties and good biocompatibility,and have attractive prospects in many fields.Therefore,the development and optimization of the preparation technology of MXene low-dimensional materials,the study of its structure-performance relationship,and the realization of high-performance applications of MXene low-dimensional materials are important frontier topics.This article mainly relates to the preparation and application of MXene nanosheets and MXene quantum dot materials.The specific work is as follows:(1)Optimized reaction conditions to prepare and characterize Ti3C2Tx nanosheets.The preparation of MXene nanosheets is the basis for subsequent composite materials and functional applications.Therefore,firstly,two methods of HF and NaF/HCl etching were used to prepare Ti3C2Tx nanosheets,and the second method is better through SEM analysis and comparison.Then,the second method was used to prepare Ti3C2TX nanosheets by controlling the hydrothermal reaction time and temperature,the prepared nanosheets were characterized by SEM and X-ray diffraction XRD,and the best reaction conditions were obtained at 180? for 12h.Finally,the optimized Ti3C2Tx nanosheets were characterized by a series of characterizations.The results are as follows:The morphology was characterized by SEM,atomic force microscope AFM and transmission electron microscope TEM,the thickness is about 3-4nm(3-4 layers);through the use of X-ray photoelectron spectroscopy XPS and infrared spectroscopy FT-IR,the surface of Ti3C2Tx nanosheets has-F,-O.(2)Research on the preparation and performance of Ti3C2Tx nanosheet/EVA composite material.The solution blending method was used to prepare Ti3C2Tx/ethylene-vinyl acetate copolymer EVA nanocomposite,which was used to improve the thermodynamic properties of EVA.SEM and FT-IR analysis showed that Ti3C2TX nanosheets are dispersed in the EVA matrix;through differential scanning calorimeter DSC,Vicat softening point tester and thermogravimetric analyzer TG characterization,it is concluded that Ti3C2Tx nanosheets improves thermal properties of EVA;tensile testing machine analysis showed that proper amount of Ti3C2Tx nanosheets enhances the mechanical properties of EVA.(3)Research on the preparation and application of Ti3C2Tx quantum dots(Ti3C2Tx QDs).The ultrasonic/solvothermal hybrid method was used to prepare Ti3C2Tx QDs,which was applied to the detection of Fe3+,ascorbic acid content and the preparation of EVA composite materials.The composition of Ti3C2Tx QDs was analyzed by FT-IR and XPS,there are functional groups such as-F and-O on the surface of Ti3C2Tx QDs;The morphology of Ti3C2Tx QDs was characterized by TEM,showing that it had good dispersibility,with an average size of 1.7 nm and a lattice spacing of 0.21 nm;Through fluorescence spectrum analysis,it is concluded that Fe3+ can effectively inhibit fluorescence,and the addition of ascorbic acid can restore the fluorescence after Fe3+quenching.The calculated detection limit of Fe3+ is 99nM,and ascorbic acid is 50nM;Through the analysis of TG and tensile testing machine,it is concluded that after adding Ti3C2Tx QDs,the tensile strength and initial degradation temperature of EVA were increased,indicating that the mechanical and thermodynamic properties of EVA have been enhanced.But,compared to Ti3C2Tx nanosheets,Ti3C2Tx QDs have a poorer effect on enhancing the thermodynamic properties of EVA.