Preparation And Electrochemical Application Of Carbon Quantum Dots Nanocomposites

Carbon quantum dots are one of the most important fluorescent carbon nano materials,and also named carbon dots,carbon nano-dots and carbon nano-crytalline,with a spherical structure that the size below 10 nm.Compared with traditional semiconductor quantum dot and dyeing materials,carbon quantum dots possess some unique advantages,such as small particle size,good solubility in water,easy functionalization and lower toxicity.Carbon quantum dots have potential value and wide application in many areas based on its unique electrical,optical and mechanical properties.The main contents were summarized as follows:1.Detection of 2,6-diaminopyridine based on carbon quantum dot by molecular imprinting techniqueIn this work,a novel electrochemical sensor for the recognition of 2,6-Diaminopyridine?2,6-DAP?based on carbon quantum dots coated with molecularly imprinted polymers?CQDs/MIPs?has been developed.The prepared core-shell nanoparticle was synthesized by using CODs as the core,2,6-DAP as the template molecule and 6-aminouracil?6-AU?as the functional monomer.The results of scanning electron microscopy?SEM?and transmission electron microscopy?TEM?indicate that the formation of the core-shell structure of imprinted films.Then electrochemical behaviors of 2,6-DAP on the surface of CQDs-MIPs were investigated by cyclic voltammetry?CV?and differential pulse voltammetry?DPV?.Under the optimal conditions,the linear response range for the determination of 2,6-DAP is 0.5²0.0 mg kg^-11 with the detection limit?S/N=3?of 0.051 mg kg^-1.Furthermore,the proposed method was successfully applied to commercial hair dyes.2.Preparation of nitrogen doped graphene/carbon quantum dots by simple hydrothermal method and simultaneous determination of dihydroxybenzene isomersIn this chapter,N-Gr/CQDs composites were prepared by hydrothermal method with sodium citrate,ammonium bicarbonate and GO,and then the prepared material was characterized by the scanning electron microscopy,transmission electron microscopy,Raman spectroscopy and electrochemical impedance spectra,UV-is spectroscopy,Raman spectroscopy and X-ray photoelectron spectroscopy.The experiments showed that N-Gr/CQDs have good conductivity,large surface area and could be dispersed well in water.The construction of the sensor achieved the simultaneous detection of hydroquinone isomers.Under the optimal conditions,the oxidation peak potentials of catechol?CC?and hydroquinone?HQ?were 336 mV and186 mV,and the peak potential difference was 15 mV,which allowed CC and HQ to be detected simultaneously.The detection range of CC was 1⁴80?M,the detection limit?S/N=3?was 0.21?M,the detection range of HQ was 0.5⁴00?M,and the detection limit?S/N=3?was 0.17?M.The N-Gr/CQDs were applied to the detection of the hydroquinone isomers in tap water,and the results were satisfactory.