Ti₃C₂ Mxene Quantum Dots Modified By Ionic Liquid

Graphene quantum dots（GQDs）have triggered tremendous attention as a new class of zero-dimensional carbon nanomaterials.Owing to the remarkable edge effects and quantum confinement,GQDs exhibit a series of excellent property.The structure of two-dimensional sheet materials,such as MXene,is very similar to the structure of graphene.When the diameter of the two-dimensional MXene structure is less than 100 nm,it will form MXene quantum dots.Ti₃C₂ is a new type of MXene material and is a typical graphene-like material,which shows great potential in the field of energy storage,bio-sensing,super-capacitors and other areas.In this work,Ti₃C₂ powder was cut into Ti₃C₂ MXene quantum dots by hydrothermal synthesis,which had excellent water solubility and fluorescent properties and.The influence of different hydrothermal parameters on quantum dots was explored and the best combination of parameters is figured out.Moreover,the ionic liquid is modified on the surface of quantum dots to enhance their fluorescence properties.The following aspects will be discussed.（1）Ti₃C₂ MXene quantum dots with diameter of 2-6 nm were prepared from Ti₃C₂powders by hydrothermal synthesis.By changing the hydrothermal temperature and alkaline agent,six different sets of Ti₃C₂ quantum dots were prepared.The hydrothermal temperature is 100℃、120℃、150℃.The alkaline agents are ammonia or lysine,respectively.（2）A series of characterizations of the prepared Ti₃C₂ MXene quantum dots were carried out,including morphology,chemical structure and fluorescence properties.The effect of hydrothermal temperature and alkaline agent on the structure and fluorescence properties of preparesd quantum dots were studied.Quantum dots with the most excellent fluorescence property had been selected and the best hydrothermal parameter combination of the preparation of quantum dots was confirmed.（3）The ionic liquid[APMIm][Br]（1-aminopropyl-3-methylimidazolium bromide）is modified on the surface of Ti₃C₂ MXene quantum dots with the help of catalysts.The structure and fluorescence property of[APMIm][Br]-Ti₃C₂ MXene quantum dots were studied and it was found that the fluorescence performance of ionic liquid-modified quantum dots was greatly improved.The mechanism of enhancing the fluorescence performance of Ti₃C₂ MXene quantum dots by ionic liquid was also discussed and the application for ion detection has been explored.