Application of metal fullerene-organic framework composite spinning functional material in oxygen detection

Abstract

The invention relates to application of a metal fullerene-organic framework composite spinning functional material in oxygen detection, and belongs to the technical field of metal fullerene composite materials. The metal fullerene-organic framework composite spinning functional material has sensitive response characteristics to oxygen molecules, and realizes real-time in-situ monitoring of oxygen gas adsorption, diffusion and concentration change processes by combining an electron paramagnetic resonance technology, so that a new method is added for an oxygen analysis technology, and oxygen analysis requirements under different working conditions are met.

Description

TECHNICAL FIELD

[0001] The application relates to an application of a metal fullerene-organic framework composite spin functional material in oxygen detection and belongs to the technical field of metal fullerene composite materials. BACKGROUND

[0002] Oxygen, as an indispensable gas in life activities and industrial production, has wide and important application value in life science, environmental monitoring, space support and industrial control process. The change of oxygen concentration is closely related to many key processes, such as combustion control, gas separation, material synthesis, environmental quality evaluation and life support system operation. Especially in systems requiring real-time feedback and dynamic control, high-sensitivity and high-timeliness oxygen detection technology has key significance for improving industrial efficiency, ensuring ecological environment safety and personnel health. In the medical field, oxygen detection is widely used in the diagnosis of respiratory system diseases (such as chronic obstructive pulmonary disease and asthma), anesthesia management, intensive care and tissue hypoxia evaluation, and the change of its concentration is a key physiological and pathological index. The commonly used gas oxygen analyzers include paramagnetic oxygen principle, zirconia principle, electrochemical principle and laser principle. The above oxygen analyzers play an important role in many fields. However, it should be pointed out that each oxygen analysis sensor has advantages and disadvantages and adapts to the environment. For example, the mainstream electrochemical principle oxygen sensor has safety hazards in flammable and explosive environments, is easily affected by flow fluctuations, affects the accuracy of measurement values, and cannot measure high humidity, toxic and harmful gases. For the laser principle oxygen sensor, pressure and temperature have a great influence. With the rapid development of current frontier technology, the requirement for oxygen analysis is getting higher and higher, so more new oxygen measurement technologies still need to be developed to meet the oxygen measurement needs under unconventional conditions.

[0003] Oxygen molecules have single electrons, which are paramagnetic molecules, so oxygen has a significant effect on electron paramagnetic resonance signals. In EPR measurement experiments, oxygen needs to be removed to eliminate the influence of oxygen. The influence of oxygen on EPR signals is reflected in the broadening and intensity, so free radical EPR technology can be used to detect oxygen in solution. However, under an oxygen atmosphere, conventional free radicals often lose activity quickly and cannot be made into an oxygen sensor.

[0004] Metal fullerene spin probes exhibit high sensitivity to changes in the external environment through the unique electronic spin characteristics of the metal cluster in the cage. The external carbon cage provides a stable chemical environment for metal atoms or clusters, forming an electronic spin center with excellent chemical stability, which exhibits unique hyperfine structure and response characteristics in electron paramagnetic resonance (EPR) spectrum detection. Among them, Sc3C2C 80The molecule is a typical endohedral metallo-carbide fullerene, and the unpaired single electron thereof is mainly located in the internal cluster of the carbon cage, which gives the molecule good paramagnetic response behavior. In a solution system containing Sc3C2C 80 , 22 highly symmetrical hyperfine splitting signals can be observed in the EPR spectrum, which reflects the high order of spin interaction. Due to the high sensitivity of the electronic spin state to factors such as molecular collision in the surrounding environment, gas concentration, charge distribution, and polarity change, Sc3C2C 80 can be used as a high-sensitivity molecular spin probe, which is suitable for detecting the physical and chemical state of the local microenvironment. The signal line type, intensity, and splitting peak number can be used as important parameters for analyzing the interaction between the probe and the environment. However, the aggregate state of Sc3C2C 80 does not have a fine EPR spectrum. Covalent organic frameworks (COFs) are a class of organic framework materials with high crystallinity, porous structure, and good thermal stability. The channel structure is ordered, contains rich functional groups, and has a molecular-scale confined space. Introducing metallofullerene molecules into COF materials can significantly improve their dispersibility while retaining their fine EPR spectrum. The present inventors previously filed a patent application CN115684239A disclosing a metallofullerene electron spin probe and found that the interaction between metallofullerene and adsorbed gas in the pore of the porous material can be used to analyze the adsorption capacity of the porous material for gas, and further used to measure the gas adsorption performance of the porous material. However, the inventors of the patent application did not find the relationship between the metallofullerene electron spin probe and the oxygen concentration, nor did they disclose the related properties of oxygen detection. SUMMARY

[0005] Therefore, the purpose of the present application is to provide an application of a metallofullerene-organic framework composite spin functional material in oxygen detection. The inventors have found that the metallofullerene-organic framework composite spin functional material has a sensitive response to oxygen molecules, and by combining electron paramagnetic resonance technology, real-time in-situ monitoring of the adsorption, diffusion, and concentration change process of oxygen gas can be achieved. This adds a new method to oxygen analysis technology, meets the demand for oxygen analysis under different working conditions, and helps the development of frontier technology.

[0006] To achieve the above-mentioned purpose, the technical solutions of the present application are as follows.

[0007] An application of a metallofullerene-organic framework composite spin functional material in oxygen detection, the application steps comprising:

[0008] The metallofullerene-organic framework composite spin functional material is loaded into a quartz paramagnetic tube, and then placed in an electron paramagnetic resonance spectrometer. One end of the quartz paramagnetic tube is connected to an oxygen detector, and the other end is connected to nitrogen gas. The nitrogen flow rate is adjusted to obtain EPR signals under different oxygen concentrations.

[0009] The peak height of the EPR signal under different oxygen concentrations is analyzed, and the relationship equation is obtained by data fitting analysis with oxygen concentration as the abscissa and peak height as the ordinate.

[0010] The quartz paramagnetic tube containing the metal fullerene-organic framework composite spin functional material is connected with the target system to be measured, and the EPR signal is collected; the oxygen content of the target system is obtained by substituting the EPR signal peak height into the relationship equation.

[0011] Further, the nitrogen flow rate is controlled below 10 ml / min. By adjusting the flow rate of nitrogen, the oxygen concentration in the quartz tube can be adjusted and controlled, thereby obtaining different oxygen concentration environments. At the same time, a lower nitrogen flow rate can ensure that the oxygen concentrations inside and outside the metal fullerene-organic framework composite spin functional material reach a sufficient balance.

[0012] Further, after adjusting the nitrogen flow rate, the oxygen content value on the oxygen detector remains unchanged for at least 5 minutes before EPR signal testing.

[0013] Further, the target system to be measured is a gas.

[0014] A metal fullerene-organic framework composite spin functional material in the preparation of an oxygen sensing module.

[0015] Further, the metal fullerene-organic framework composite spin functional material is composed of an organic framework material and metal fullerenes adsorbed in the pores of the organic framework material.

[0016] Further, in the metal fullerene-organic framework composite spin functional material, the metal fullerenes are Sc3C2C 80 paramagnetic molecules; further, the mass fraction of metal fullerenes is 1 ‰-30 ‰.

[0017] Further, the organic framework material is a covalent organic framework (COFs) material. Further, the covalent organic framework material includes Py-COF, Py-1P-COF, Py-2P-COF, TpPa-1.

[0018] Further, the metal fullerene-organic framework composite spin functional material is prepared by the following method, the method steps including: adding an organic framework material into a metal fullerene solution, soaking sufficiently, allowing the metal fullerenes to diffuse into the pores of the organic framework material, vacuum drying after soaking, and obtaining a metal fullerene-organic framework composite spin functional material.

[0019] Further, the concentration of the metal fullerene solution is 10 -7 mol / L-10-4 mol / L, with toluene, xylene, trimethylbenzene, chlorobenzene, o-dichlorobenzene, or trichlorobenzene as the solvent.

[0020] Furthermore, the soaking time is 1 to 7 days.

[0021] Beneficial effects

[0022] This invention leverages the newly discovered sensitive response characteristics of a metal-fullerene-organic framework composite spin functional material to oxygen molecules, applying this material to the measurement and analysis of oxygen concentration. This composite material exhibits structural stability and strong repeatability of its spin signal, allowing it to be designed as an oxygen sensing module integrated with an electron paramagnetic resonance (EPR) spectrometer. Direct communication with the analyte system enables oxygen concentration measurement and analysis. This method is particularly suitable for applications requiring high precision and stability in oxygen concentration monitoring. It is also applicable to oxygen measurement in flammable and explosive gases, under high pressure or ultra-high vacuum conditions, and for non-contact, non-destructive oxygen measurement in fragile systems. The metal-fullerene-organic framework composite spin functional material maintains a stable EPR response signal in the part-in-a-million (ppm) oxygen concentration range, demonstrating excellent linearity and making it suitable for ultra-low oxygen content detection in high-tech fields. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the device used in an embodiment of the present invention.

[0024] Figure 2 The Sc3C2C prepared in Example 1 80 Optical photograph of @Py-COF spin-functionalized material.

[0025] Figure 3 The Sc3C2C described in Example 1 80 @Py-COF spin functional material response to oxygen concentration variation.

[0026] Figure 4 The Sc3C2C described in Example 1 80 @Py-COF spin functional materials show a linear relationship between oxygen concentration and EPR peak height.

[0027] Figure 5 The Sc3C2C described in Example 1 80 The trend of EPR signal peak intensity of @Py-COF spin functional materials with nitrogen pressure.

[0028] Figure 6 The Sc3C2C described in Example 1 80 EPR signals of @Py-COF spin functional materials in air and high-purity oxygen atmospheres. Detailed Implementation

[0029] The application will be further described in detail below in combination with specific embodiments.

[0030] In the application, the metallofullerene-organic framework composite material is composed of endohedral metallofullerene and organic framework material.

[0031] The metallofullerene is Sc3C2C 80 molecule.

[0032] The organic framework material refers to covalent organic framework (COFs) material, which can be specifically Py-COF, Py-1P-COF, Py-2P-COF, TpPa-1, etc.

[0033] The metallofullerene-organic framework composite spin functional material is prepared according to a method comprising the following steps: configuring a metallofullerene solution with a certain concentration, soaking a proper amount of organic framework material in the metallofullerene solution, fully soaking, diffusing the metallofullerene into the pores of the organic framework, and finally obtaining the metallofullerene-organic framework composite material.

[0034] The endohedral metallofullerene solution takes endohedral metallofullerene as solute, and the solvent can be one of toluene, xylene, trimethylbenzene, chlorobenzene, o-dichlorobenzene and trichlorobenzene.

[0035] The concentration of the endohedral metallofullerene solution can be between 10 -7 mol / L and 10 -4 mol / L.

[0036] The soaking time is 1-7 days.

[0037] The obtained metallofullerene-organic framework composite material should be vacuum dried to remove solvent molecules.

[0038] The mass fraction of metallofullerene in the metallofullerene-organic framework composite material is 1 ‰-30 ‰.

[0039] As Figure 1 shown, the metallofullerene-organic framework composite spin functional material provided by the application can be used for oxygen concentration measurement, and first a standard curve of spin signal and oxygen concentration dependence should be drawn.

[0040] The standard curve drawing test of the spin signal and oxygen concentration dependence includes the following steps: an appropriate amount of metal fullerene-organic framework composite spin functional material is loaded into a quartz tube, which is then placed in an electron paramagnetic resonance spectrometer, one end of the paramagnetic tube is connected to an oxygen detector through a gas pipe, and the other end is connected to nitrogen, the nitrogen flow rate is controlled by a regulating valve under normal pressure, and the EPR signal is measured under different oxygen concentrations.

[0041] In the test, the oxygen concentration in the quartz tube is adjusted and controlled by adjusting the flow rate of nitrogen, thereby obtaining different oxygen concentration environments. The nitrogen flow rate is controlled below 10 ml / min, and low flow rate can make the oxygen concentration inside and outside the porous material reach sufficient balance.

[0042] In the test, the nitrogen flow rate is finely adjusted so that the oxygen content on the oxygen detector remains unchanged for at least 5 minutes before the EPR signal test is performed.

[0043] In the test, the EPR signal peak height under different oxygen concentrations is analyzed, and the data fitting analysis is performed with oxygen concentration as the abscissa and peak height as the ordinate. The experimental results show that the composite spin functional material exhibits regular EPR signal changes under different oxygen content conditions, exhibits an exponential dependence, and the relationship equation is obtained according to the fitting.

[0044] The metal fullerene-organic framework composite spin functional material described above is kept intact for oxygen concentration measurement, which includes the following steps: based on the calibration test of the spin signal and oxygen concentration, the EPR signal peak height of the spin functional material measured in the target system is substituted into the equation, and the oxygen concentration of the target system can be obtained.

[0045] In the measurement, different batches of composite spin functional materials have different EPR signal peak heights and oxygen concentration dependence relationships, so different relationship equations will be fitted. In actual application, equation analysis and data substitution calculation should be performed according to the type and batch of composite material used.

[0046] In the measurement method, the linear equation obtained by fitting has a wide range of applications. This detection method can be further expanded to measure up to 100% oxygen concentration, or as low as one part per million oxygen concentration.

[0047] In the following examples, the experimental methods used are conventional unless otherwise specified; the reagents, materials, etc. used in the following examples can be obtained from commercial sources unless otherwise specified.

[0048] The following relates to Compound 1, which is commercially available under the trade name Py-COF.

[0049] Example 1:

[0050] Sc3C2C 80 @Synthesis of Py-COF spin functional material: 2 mg of Py-COF was weighed and immersed in a toluene solution (1 mL) of 5.76 x 10 -5 mol / L Sc3C2C 80 , and after 7 days of sufficient adsorption, the solid was taken out and vacuum dried. According to the change in solution concentration before and after adsorption, the mass fraction of Sc3C2@C 80 adsorbed by Py-COF was 14.7 ‰. Sc3C2C 80 @The optical photograph of Py-COF composite material is shown in Figure 2 .

[0051] Example 2:

[0052] Sc3C2C 80 @Py-COF spin functional material: The dried spin functional material was placed in a quartz tube and connected to a high-purity nitrogen gas and oxygen concentration detector through a gas pipe. Then the quartz tube was placed in the resonance cavity of the electron paramagnetic resonance spectrometer, and the flow rate of nitrogen was adjusted to achieve the adjustment and control of the oxygen concentration in the quartz tube, thereby obtaining different oxygen concentration environments. The oxygen content range in this example was controlled between 1% and 20.9%. The EPR signal was tested under different oxygen content conditions, and the test was repeated 3 times.

[0053] Figure 3 Sc3C2C 80 @Py-COF probe: The EPR spectrum of the probe under different oxygen content conditions is shown in the figure. The peak-to-peak intensity of the measured EPR signal was analyzed to obtain the trend of the EPR signal peak height of the material with the change of oxygen content.

[0054] As shown in Figure 4 , the EPR peak height gradually weakens with the increase of oxygen concentration, showing an exponential response relationship. The experimental data was fitted to obtain the relationship equation between EPR peak height and oxygen concentration. According to this mathematical equation, in actual use, the target system is connected to the quartz tube, and the measured EPR signal peak height of the spin functional material is substituted into this equation to solve the oxygen content of the target system, realizing the quantitative analysis of the oxygen content in the system.

[0055] Example 3:

[0056] Sc3C2C 80 @Py-COF spin functional material: The dried spin functional material was placed in a quartz tube and connected to a high-purity nitrogen gas and oxygen concentration detector through a gas pipe. Then the quartz tube was placed in the resonance cavity of the electron paramagnetic resonance spectrometer, and the flow rate of nitrogen was adjusted to achieve the adjustment and control of the oxygen concentration in the quartz tube, thereby obtaining different oxygen concentration environments. The oxygen content range in this example was controlled between 1% and 20.9%. The EPR signal was tested under different oxygen content conditions, and the test was repeated 3 times. 80The quartz tube of the Py-COF material is connected to the gas to be measured through a gas pipe to collect the electron paramagnetic resonance signal of the spin functional material, and the peak-to-peak value is recorded as 12.6. Then the signal value is substituted into the standard fitting curve established in Example 2: y = 7.33 * exp(-(x-0.94) / 11.19) + 10.68, and the oxygen content of the gas bag is about 15.8% by inverse solving.

[0057] Example 4:

[0058] The experimental operation of Example 3 is repeated, and is connected to another gas with different oxygen content to be measured. The electron paramagnetic resonance signal of the material is collected using EPR, and the peak-to-peak value is obtained as 14.5. Then the signal value is substituted into the standard fitting curve established in Example 2: y = 7.33 * exp(-(x-0.94) / 11.19) + 10.68, and the oxygen content of the system is about 8.3% by inverse solving.

[0059] Example 5:

[0060] Example 1 Sc3C2C 80 @Py-COF spin functional material and nitrogen gas relationship comparison: Sc3C2C 80 The quartz tube of the Py-COF material is connected to the gas to be measured through a gas pipe to collect the electron paramagnetic resonance signal of the spin functional material, and the peak-to-peak value is recorded as 12.6. Then the signal value is substituted into the standard fitting curve established in Example 2: y = 7.33 * exp(-(x-0.94) / 11.19) + 10.68, and the oxygen content of the gas bag is about 15.8% by inverse solving.

[0061] Figure 5 Example 1 Sc3C2C 80 @Py-COF probe EPR signal peak intensity with the change trend of nitrogen gas pressure, under different nitrogen pressure, the measured EPR signal intensity does not change significantly. It shows that in the research system of this experiment, nitrogen as a gas to adjust the oxygen partial pressure, the change of nitrogen partial pressure has no significant effect on the EPR signal intensity of the sample.

[0062] Example 6:

[0063] This example further compares the Sc3C2C 80 @Py-COF spin functional material in air (containing 20.9% O2) and high purity oxygen (99.99%) atmosphere EPR signal. As Figure 6 shown, Sc3C2C 80 @Py-COF spin functional material in high purity oxygen atmosphere still shows lower EPR signal than in air, which shows that Sc3C2C 80The Py-COF spin functional material also has signal response in a high-concentration oxygen environment, proving that it can be applied to detection in a high-concentration oxygen range.

[0064] In conclusion, the application includes but is not limited to the above embodiments, any equivalent replacement or partial improvement made under the spirit and principle of the application shall be considered within the protection scope of the application.

Claims

1. The application of a metal fullerene-organic framework composite spin functional material in oxygen detection, characterized in that: The application steps include: Metal fullerene-organic framework composite spin functional material was loaded into a quartz paramagnetic tube and then placed in an electron paramagnetic resonance spectrometer. One end of the quartz paramagnetic tube was connected to an oxygen detector, and the other end was connected to nitrogen gas. The nitrogen gas flow rate was adjusted to obtain EPR signals at different oxygen concentrations. The peak height of EPR signals under different oxygen concentrations was analyzed. With oxygen concentration as the abscissa and peak height as the ordinate, data fitting analysis was performed to obtain the relationship equation. A quartz paramagnetic tube containing a metal fullerene-organic framework composite spin functional material is connected to the target system to collect the EPR signal; the oxygen content of the target system is obtained by substituting the peak height of the EPR signal into the relational equation.

2. The application of the metal fullerene-organic framework composite spin functional material as described in claim 1 in oxygen detection, characterized in that: The nitrogen flow rate should be controlled below 10 ml / min.

3. The application of the metal fullerene-organic framework composite spin functional material as described in claim 1 in oxygen detection, characterized in that: After adjusting the nitrogen flow rate, wait for the oxygen content value on the oxygen detector to remain unchanged for at least 5 minutes before performing the EPR signal test.

4. The application of the metal fullerene-organic framework composite spin functional material as described in claim 1 in oxygen detection, characterized in that: The target system to be tested is a gas.

5. Application of a metal fullerene-organic framework composite spin functional material in the preparation of oxygen sensing modules.

6. The application as described in claim 1 or 5, characterized in that: The metal fullerene-organic framework composite spin functional material is composed of an organic framework material and metal fullerenes adsorbed in the pores of the organic framework material.

7. The application as described in claim 6, characterized in that: In the metal fullerene-organic framework composite spin functional material, the metal fullerene is Sc3C2C. 80 Paramagnetic molecules; and / or, the mass fraction of metallofullerenes is 1‰ to 30‰.

8. The application as described in claim 6, characterized in that: The organic framework material is a covalent organic framework material, and the preferred covalent organic framework materials include Py-COF, Py-1P-COF, Py-2P-COF, and TpPa-1.

9. The application as described in claim 6, characterized in that: The metal fullerene-organic framework composite spin functional material is prepared by the following method, which includes: adding the organic framework material into the metal fullerene solution, soaking it thoroughly to allow the metal fullerene to diffuse into the pores of the organic framework material, and vacuum drying after soaking to obtain the metal fullerene-organic framework composite spin functional material.

10. The application as described in claim 9, characterized in that: The concentration of the metallofullerene solution is 10. -7 mol / L~10 -4 The concentration is mol / L, and the solvent is toluene, xylene, trimethylbenzene, chlorobenzene, o-dichlorobenzene, or trichlorobenzene; the soaking time is 1 to 7 days.

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