Study On Preparation Of Fluorescent Carbon Dots And Their Applications For The Detection Of Doxorubicin And Improvement Of Photocatalytic Performance Of WO₃

Carbon Dots?CDs?have a very wide range of applications in biomedical,pharmaceutical analysis and photocatalysis due to their excellent fluorescence,low toxicity and good biocompatibility and photoelectric properties.Although carbon has made great progress in the preparation of the method,but to find a more economical and environmentally friendly carbon source and a more simple synthesis method to prepare a higher quantum yield of fluorescent carbon is still the main point of the current fluorescent one of the research directions.In this paper,two kinds of fluorescent materials with high quantum yield were prepared by two different methods,and their morphology,structure and optical properties were studied in depth.At the same time,the two kinds of fluorescent carbon spots were investigated.And the application of photocatalysis.The specific research contents are as follows:1?Using citric acid and urea as carbon source,deionized water as solvent,solid-state method to synthesize blue light CDs.The morphology,structure,surface groups and optical properties of carbon dots were characterized by TEM,XRD,FTIR,fluorescence spectroscopy and UV-Vis absorption spectra.In order to obtain a better fluorescent light,the reaction conditions such as reaction temperature,reaction time and urea dosage were optimized.In addition,the effects of pH and inorganic salt ions on the fluorescence intensity of CDs solution were also investigated.The results show that the average particle size of CDs is 3-4nm,XRD shows the characteristic peaks of amorphous carbon;Its surface with hydroxyl and carbonyl and other groups,hydrophilic solubility is good;quantum yield as high as 30.4%,good luminous performance;The pH value of solution has a certain effect on the emission of carbon point.When the pH value is 7.0,the fluorescence intensity is the largest.The prepared carbon point has good anti-bleaching and salt resistance.A new method for quantitative analysis of doxorubicin was established by quenching the fluorescence of the carbon spot based on the resonance energy transfer between the carbon dots and doxorubicin.The experimental results show that the concentration of adriamycin in the range of 0.67-33.67mg/mL has a good linear relationship with the fluorescence quenching of the carbon dots?R²=0.9950?,and th corresponding working curve is F=9.589+36.97C?mg/mL?.In addition,the detection limit of this method was 0.43mg/mL,the recovery was 83.0%89.2%,and the relative standard deviation was less than 2.5%?n=5?.The interference of common substances in urine samples is small,which indicates that the method has good selectivity.2?The use of hydrothermal method to tannic acid as a carbon source,polyethylene imine?PEI?as a passivation agent in the phosphate medium in one step synthesis of blue fluorescent carbon.The fluorescence properties,morphology,structure and surface groups of carbon dots were characterized by fluorescence spectroscopy,UV absorption spectroscopy,XRD,TEM,FTIR and XPS.The reaction time,the reaction temperature and the amount of PEI were optimized.The effects of pH and inorganic salt on the fluorescence intensity of the prepared carbon dots were discussed.The results show that the obtained CDs have an amorphous characteristic peak with an average particle size of about 8.5 nm.The surface has a hydroxyl group,a carbonyl group and an amino group,which has good hydrophilicity and a fluorescence quantum yield of 25.4%;Also found that:the carbon point has good light stability,salt resistance,pH=7.0 when the strongest light.CDs doped WO₃ composites were prepared by using the prepared carbon dots.The photocatalytic degradation of methylene blue was investigated by Hg lamp irradiation.The effects of catalytic system,light and catalyst dosage on the photocatalytic degradation of methylene blue were investigated.The results show that the absorption band of WO₃ is red shifted from 423nm to 451nm,and the range of absorbed light is broadened.In addition,it was found that the photocatalytic activity of WO₃ was significantly improved after CDs doping compared with WO₃ alone.When the dosage of CDs/WO₃ was 0.05 g and the irradiation time was 120 min,the degradation rate of methylene blue was 80.7%.Thus,the CDs prepared by this method as a dopant can be used to improve the performance of WO₃ or other photocatalysts.