Green Preparation Of Novel-Carbon Nanomaterials And Their Application In Chemo-/Bio-Sensing

The synthesis of novel carbon nano-materials has important implications for the improvement of chemical/biological sensor performance.The new carbon nanomaterials studied in this paper mainly include:three-dimensional graphene materials and carbon quantum dots.In this study,three-dimensional graphene and various types of carbon quantum dot materials prepared by the green method using graphene oxide materials and biomass materials as precursors respectively,and was applied them to the preparation of biological/chemical sensors for the detection of phytohormones and heavy metal ions.It’s properties and morphology were studied by various characterization methods.The main content includes the following aspects:1.Three-dimensional graphene materials were prepared by a novel green method（chemical prereduction/electro-reduction）.Using this three-dimensional graphene material as a carrier,and then the thiolated polypyrrole/3D graphene nanocomposite materials were synthesized by electrochemical assisted thiol-based click method.And the gold nanoparticles were efficiently dispersed on the surface and a selective and sensitive electrochemical immunosensor for IAAdetection was prepared by double signal amplification.The sensor was linear in the range of 0.2 to 1000 pg/mL with a detection limit of 0.13 pg/mL（S/N=3）.In addition,the prepared electrochemical immunosensors are used to determine IAA in several plant-related extract samples with satisfactory selectivity,reproducibility and stability.2.A three-dimensional graphene material was prepared based on a pre-reduction/electro-reduction method was reported.And the AuNPs/3D graphene nanocomposite was synthesized by electrochemical deposition method,next the IAA antibody was loaded by electrostatic adsorption and covalent bonding for preparing the selective and high sensitive electrochemical immunosensors for IAA detection.Scanning electron microscopy（SEM）and DPV were used to characterize the modification of the glassy carbon electrode.The linear range of the electrochemical immunosensor was 2×10^-112×10^-8 g/mL,the detection limit was 0.016 ng/mL（S/N=3）,and the linear correlation coefficient was R²=0.9970.In addition,the proposed immunosensor showed satisfactory selectivity and stability and was used to determine IAA in plant-related extract samples.3.The heteroatoms-co-doped carbon quantum dots with blue fluorescence were prepared by hydrothermal method,and then purified by column,rotary evaporation using initial red pigment product extracted from purple sweet potato as carbon source,and their properties were characterized.TEM show that the size of the prepared nanoparticles is about10 nm.UV-Vis spectroscopy show the carbon quantum dots have a larger absorption peak at277 nm.Fluorescence spectroscopy show that carbon quantum dots have an excitation-independent emission at 440 nm with good stability in concentrated salt solutions and acid-alkaline solution.In addition,the response of carbon quantum dots to metal ions was investigated.The results show that the carbon quantum dots have potential applications in the selective detection of Fe³⁺.4.Based on a green synthesis of Carbon Quantum Dots（CQDs）using eucalyptus seeds as a carbon source and a three-dimensional graphene material（3DrGo）prepared using a chemical prereduction/electroreduction method,a CQDs-3DrGo/GCE based electrochemical sensor with sensitivity and selectivity for the simultaneous detection of heavy metal ions Cd²⁺and Pb²⁺was reported.The sensor has good linearity in the detection of Cd²⁺:50-12750μg/L,Pb²⁺:10-12200μg/L.The detection limits are 28.4μg/L for Cd²⁺and 8.27μg/L for Pb²⁺,respectively.And it has good repeatability and selectivity.In addition,this electrochemical sensor was applied to the simultaneous detection of Cd²⁺and Pb²⁺concentrations from Liuyang river water with a satisfactory test recovery.