Preparation Of Carbon And Gold Nanomaterials And Their Application In Optical Sensors

In recent years,new nano materials have attracted much attention because of their excellent physical and chemical properties,and have been widely used in biology,environment,pharmacy,sensor and and other fields.In this paper,carbon nanoparticles with three different carbon sources and gold nanoparticles were prepared and their applications in optical sensor detection were studied.The main research contents are as follows:1.Optimization of synthesis conditions,preparation and characterization of carbon nanoparticlesCarbon nanomaterials were prepared using graphite and polyacrylonitrile-based carbon fibers as carbon sources by hydrothermal synthesis with mixed acid,and nitrogen-doped carbon nanomaterials were prepared using urea as nitrogen source and graphene oxide?GO?as carbon source.The three materials were characterized by transmission electron microscopy?TEM?,X-ray photoelectron spectroscopy?XPS?,Fourier transform infrared spectroscopy?FT-IR?,Zeta potentiometry and Raman spectroscopy.2.A sensor with the same properties as enzymes for detection of hydrogen peroxide was constructed from carbon nanomaterialsWe determined the peroxidase-like catalytic activity of carbon nanomaterials.The results showed that the carbon nanomaterials had similar properties to natural enzymes,whose activity is closely related to pH,temperature and substrate concentration.Through the optimization of experimental conditions:pH 3-5 is the most suitable use range of carbon nano enzyme;the catalytic activity of carbon nano enzyme increases with the increase of temperature;in a certain range,the initial speed of enzymatic reaction is proportional to the substrate concentration.The Michaelis constant?K_m?and the maximum reaction rate(V_max)of the three materials were calculated by the double reciprocal graphic method and compared.In addition,we also constructed a simple,rapid,highly selective and sensitive colorimetric method to determine the concentration of H₂O₂.The linear range of detection was 0.02-0.2?0.4?mmol/L,and the detection limits were 0.012 mmol/L,0.015 mmol/L and 0.014 mmol/L,respectively.The study also showed that the three carbon nanomaterials had similar catalytic efficiency for the removal of certain phenolic compounds.3.A sensor with the same properties as enzymes for detection of hydrogen peroxide was constructed using copper oxide loaded carbon nanomaterialsIn this work,three G-Cuo composite nanomaterials with different morphologies were synthesized by in-situ growth method by controlling the mass ratio of graphene and Cu O,and the prepared materials were characterized by scanning electron microscopy?SEM?and transmission electron microscopy?TEM?.The experimental results showed that the material had good peroxidase-like catalytic activity.Under the optimized experimental conditions,the K_m and V_max of the three materials were compared,and it was proved that nanomaterials with different morphologies and particle sizes could be obtained with different mass ratios.It was speculated that the physical scale of the materials had an important influence on the catalytic performance.The material could be used to construct a simple,fast,highly selective and sensitive colorimetric method for quantitative determination of H₂O₂ concentration.The linear range of detection was0.02-0.16mmol/L,and the detection limits were 0.012mmol/L,0.013mmol/L and 0.016mmol/L respectively.4.Rhodamine B modified gold nanometer star to construct a fluorescence sensor for detecting zinc ionsGold nano star can cause the fluorescence intensity of Rhodamine B to turn off obviously,but in the presence of zinc ion,the fluorescence intensity of Rhodamine B will gradually recover?turn on?,and the fluorescence recovery rate has a good linear relationship with the concentration of zinc ion.The linear range was 0.2?mol/L-5mmol/L,and the minimum detection limit was 0.13?mol/L.Therefore,we had built an efficient,convenient and simple fluorescent sensor for detecting zinc ions,which had certain application potential.5.Rhodamine B modified gold nanoparticles to construct a fluorescence sensor for detecting supramolecular compound cucurbituril[7]?CB[7]?Gold nanoparticles can cause the fluorescence intensity of Rhodamine B to turn off obviously,but in the presence of CB[7],the fluorescence intensity of RhB gradually recovered,and the fluorescence recovery rate showed a good linear relationship with CB[7]concentration.The linear range was 0.8-8?g/mL,and the minimum detection limit was 0.18?g/m L.Therefore,we constructed an efficient,convenient,quick and simple method for detecting CB[7].This method can not only build"turn on-off"fluorescent sensors,can also be based on the identification of subject and object to test the CB[7],this method can effectively distinguish between CB[7]and other macrocyclic compounds,such as CB[5],CB[6]and?-CD.