Design And Preparation Based On Carbon Nitride Nanoprobe And Its Application In Photochemical Sensing

As a non-metallic two-dimensional material,graphite carbonitride(g-C3N4)is widely used in photocatalysis,optical devices and biosensing due to its good catalytic performance.In recent years,with its long-lasting fluorescence and high specific surface area,it has been widely used to detect a large number of biomolecules,and the research heat is increasing.At the same time,the commonly used bulky carbonized nitrogen(g-C3N4)is passed through organic precursors at high temperatures.Under the self-polymerization,there are shortcomings such as low specific surface area,serious electron-hole recombination and low dispersion in common solvents.These defects limit the application of carbonized nitrogen to varying degrees.In order to further optimize the synthesis method and application of g-C3N4,this paper synthesized g-C3N4 material by simple synthesis method and applied it to photochemical sensing research.The main results achieved are as follows:(1)Preparation of iron-doped graphite carbonitride nitrogen(Fe-C3N4)nano-mimetic enzyme material by one-step high-temperature calcination,using X-ray powder diffraction(XRD),scanning electron microscopy(SEM),transmission electron microscopy(TEM),X-ray Photoelectron spectrometer(XPS),nitrogen physical adsorption(BET),thermogravimetric analyzer(TA),Fourier infrared spectrometer(FI-IR),ultraviolet spectrophotometer(UV-Vis)and fluorescence spectrophotometer(The morphology,structure and properties of the synthesized Fe-C3N4 were characterized by means of FL).The experimental results show that the prepared Fe-C3N4 material exhibits excellent hydrogen peroxide mimic enzyme activity,and its reaction with hydrogen peroxide is achieved by electron transfer.Fe-C3N4 was successfully applied to the detection of hydrogen peroxide and glucose.The optimum test conditions were as follows:pH=5,at a material concentration of 2 mg/L at 65 0C.The hydrogen peroxide reaction was carried out for 5 min and then tested.The final linear detection range of hydrogen peroxide is 5 nM-400 μM with a detection limit of 1.3 nM,the linear range of glucose is 1 μM-100μM,and the detection limit is 0.5 μM.Fe-C3N4 has high selectivity and excellent anti-interference performance for the detection of hydrogen peroxide.(2)Nitrogen carbide quantum dots(CNQDs)were synthesized by solvothermal method using graphite carbonitride nanosheets(g-C3N4)as precursor.X-ray diffraction(XRD),field emission transmission electron microscopy(TEM),atomic force microscopy(AFM),Fourier transform infrared spectroscopy(FI-IR),X-ray energy spectroscopy(XPS),ultraviolet spectrophotometer(UV-Vis)The synthesized quantum dots were characterized by fluorescence spectroscopy.The results show that the synthesized CNQDs contain CN,NH,C=N functional groups and have good photostability and time stability.By analyzing the UV spectrum and fluorescence excitation emission spectrum analysis of quantum dots and antibiotics,oxytetracycline and tetracycline will quench the fluorescence of CNQDs by internal filter effect and apply it to the antibiotics oxytetracycline(OTC)and tetracycline(TC).Fluorescence sensing detection.Under the optimal test conditions,the linear range of OTC is 0.01 nM-3 nM,the detection limit is 0.0075 nM,the linear range of TC is 5 nM-100 nM,and the detection limit is 0.1 nM.Different concentrations of OTC and TC can be detected by naked eyes under 365 nm UV illumination.And for the rest of the class of antibiotics and common interferences have good anti-interference characteristics.(3)Carbonized nitrogen quantum dots(CNQDs)were synthesized by means of ethylene glycol solvothermal method,using field emission transmission electron microscopy(TEM),X-ray energy spectrum(XPS),fluorescence quantum yield,fluorescence lifetime and fluorescence photometer(the synthesized quantum dots were characterized by means of FL).The results show that the synthesized CNQDs do have characteristic diffraction fringes,high quantum dot yield and long-lasting fluorescence stability,and are applied to the detection of glucose and hydrogen peroxide.The optimal conditions were obtained by optimizing the reaction conditions:taking 150 μL of CNQDs stock solution,diluting to 3 mL with phosphate buffered saline(PBS)at pH=7,reacting with antibiotics for 1 min,and performing fluorescence test.The test results showed that the linear range of hydrogen peroxide is 0.005 nM-1.8 nM,the detection limit is 0.001nM,the linear range of glucose is 5 nM-100 nM,the detection limit is 1 nM,and the selectivity and anti-interference of the reaction system are tested.The test results show that the reaction system is stable and accurate.