Nitrogen dioxide detection method

Abstract

The invention discloses a nitrogen dioxide detection method. A nitrogen dioxide sensor adopted in the nitrogen dioxide detection method comprises an MXene doped ZnO material. The method comprises the following steps: dropwise adding sol-gel onto a substrate, and heating and calcining to obtain MXene doped ZnO. The MXene has excellent heat and electricity conduction, performance and stability. The nitrogen dioxide sensor based on MXene doped ZnO has the advantages of high sensitivity, high selectivity, strong repeatability and good stability, the power consumption of the sensor in the use process is greatly reduced, the use portability of the sensor is improved, and the nitrogen dioxide sensor has important practice and research values in the technical field.

Description

Technical Field

[0001] The present application relates to a method for detecting nitrogen dioxide, and belongs to the technical field of nanomaterial preparation. Background Art

[0002] With the continuous development of productivity and the improvement of quality of life, people's demands for production and life are getting higher and higher, which has promoted the increase in demand for toxic gas sensors. The research and development of gas sensors, especially the research on harmful gas sensors, has developed extremely rapidly. Nitrogen dioxide is a toxic and pungent gas pollutant, which is commonly found in exhaust emissions from industrial production and the combustion of nitrogen-containing fuels. At present, gas sensors for detecting nitrogen dioxide have been widely used in production and life. Commonly used metal oxide materials (such as zinc oxide, tin oxide, cobalt oxide, etc.), but the detection temperature is relatively high and cannot be used in daily life. How to improve the sensitivity of nitrogen dioxide detectors and reduce the detection temperature is the key to the research of nitrogen dioxide gas sensors. Summary of the invention

[0003] According to one aspect of the present application, a method for detecting nitrogen dioxide is provided, wherein a nitrogen dioxide sensor used in the method for detecting nitrogen dioxide comprises a MXene-doped ZnO material;

[0004] The MXene is selected from at least one of an accordion-shaped, multi-layered, and single-layered shape.

[0005] Optionally, the method for preparing the MXene-doped ZnO material comprises the following steps:

[0006] (1) subjecting a mixture containing a zinc ion salt solution, an organic solvent, and an auxiliary agent to ultrasonication and stirring to obtain a sol;

[0007] (2) After mixing the sol in step (1) and the MXene powder, the mixture is dropped onto a heat-resistant substrate and calcined to obtain the MXene-doped ZnO material.

[0008] Optionally, in step (1), the zinc ion salt solution is selected from at least one of zinc acetate, zinc nitrate and zinc chloride.

[0009] Optionally, the concentration of the zinc ion salt solution is 0.01-10 g / L.

[0010] Optionally, the concentration of the zinc ion salt solution is selected from any value among 0.01 g / L, 0.05 g / L, 1 g / L, 2 g / L, 5 g / L, 7 g / L, 10 g / L or a range between any two of the above.

[0011] Optionally, the concentration of the zinc ion salt solution is 0.05-1 g / L.

[0012] Optionally, the dosage of the organic solvent, zinc ion salt solution and auxiliary agent is: 100-1000mL: 5-30g: 10-1000μL.

[0013] Optionally, the organic solvent is selected from at least one of ethanol, propanol, isopropanol, carbon tetrachloride and acetone.

[0014] Optionally, the auxiliary agent is selected from at least one of PVP, PVA, TEOS and ethanolamine.

[0015] Optionally, in step (2), the amount of MXene powder used is 0.001 to 10 g.

[0016] Optionally, in step (2), the amount of the MXene powder is selected from any value among 0.001g, 0.005g, 0.01g, 0.05g, 0.1g, 0.5g, 1g, 2g, 5g, 8g, 10g or a range between any two of the above.

[0017] Optionally, in step (2), the amount of MXene powder used is 0.01 to 1 g.

[0018] Optionally, in step (2), the heat-resistant substrate is selected from at least one of alumina, polyimide, and silica.

[0019] Optionally, in step (1), the ultrasonication time is 1 to 12 hours, and the stirring time is 6 to 36 hours.

[0020] Optionally, the ultrasound time is selected from any value of 1h, 2h, 5h, 7h, 8h, 10h, 12h or a range between any two of the above.

[0021] Optionally, the stirring time is selected from any value of 6h, 10h, 12h, 16h, 20h, 24h, 30h, 36h or a range between any two of the above.

[0022] Optionally, in step (2), the dripping conditions are: a single dripping amount is 1 to 20 uL, and the number of dripping times is 1 to 10 times.

[0023] Optionally, in step (2), the calcination temperature is 150 to 600° C., and the calcination time is 1 to 24 hours.

[0024] Optionally, the calcination temperature is selected from any value of 150°C, 200°C, 250°C, 300°C, 400°C, 500°C, 600°C or a range between any two of the above values.

[0025] Optionally, the calcination time is selected from any value of 1 h, 3 h, 6 h, 12 h, 18 h, 24 h, or a range between any two of the above.

[0026] This application is implemented through the following technical solutions:

[0027] A method for preparing MXene-doped ZnO for nitrogen dioxide detection.

[0028] (1) Preparation of sol: 5 mL of organic solvent was measured, and a certain amount of zinc ion salt solution and additives were added. After ultrasonic removal of bubbles, the sol was stirred at room temperature until uniform.

[0029] (2) MXene doping: adding a certain amount of MXene powder to the sol of step (1), stirring the mixture sufficiently at room temperature and setting aside;

[0030] (3) High-temperature calcination: Take a certain amount of the above sol and add it to a heat-resistant substrate a certain number of times, and calcine it at high temperature for a certain period of time.

[0031] Optionally, in step (1), the amount of the auxiliary agent added is 10 to 1000 μL, preferably 50 to 100 μL.

[0032] The method can obtain MXene-doped ZnO by dropping sol-gel onto a substrate and heating and calcining. MXene itself has excellent thermal and electrical conductivity, performance and stability. The MXene-doped ZnO of the present invention exhibits excellent sensitivity at room temperature, greatly reduces the power consumption during the use of the sensor, and improves the portability of the sensor, which has important practical and research value in the field of this technology.

[0033] The beneficial effects of this application include:

[0034] 1) The MXene-doped ZnO provided in this application has a simple process, good stability, and is suitable for mass production.

[0035] 2) The MXene-doped ZnO provided in this application exhibits a good and stable response to NO2. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is a 2 μm scale SEM characterization image of MXene-doped ZnO in Example 1 of the present application.

[0037] Figure 2 This is the sensing curve of MXene-doped ZnO in Example 3 of the present application. DETAILED DESCRIPTION

[0038] The present application is described in detail below with reference to embodiments, but the present application is not limited to these embodiments.

[0039] Unless otherwise specified, the raw materials in the examples of this application were purchased through commercial channels.

[0040] In the examples of the present application, a field emission electron microscope (FESEM, FEI Nova Nano SEM 450) was used to perform SEM morphology characterization of the MXene-doped ZnO material.

[0041] Example 1

[0042] Measure 10 mL of propanol, add 0.5 g of zinc chloride and 200 μL of ethanolamine, ultrasonicate for 2 h, and then continue stirring for 12 h. After adding 1 g of accordion-shaped MXene to the above sol, continue stirring for 24 h to obtain a homogeneous sol. Add 5 μL of the homogeneous sol to the PI film substrate and calcine at 400 ° C in a muffle furnace for 1.5 h to obtain MXene-doped ZnO material.

[0043] Example 2

[0044] Measure 6mL of isopropanol, add 1g of zinc nitrate and 150μL of ethanolamine, ultrasonicate for 5h, and then continue stirring for 24h. After adding 1.5g of monolayer MXene to the above sol, continue stirring for 36h to obtain a homogeneous sol. After dropping 4μL of homogeneous sol on the alumina substrate, wait for the solvent to evaporate, and continue to drop 4μL of homogeneous sol. Calcinate at 250℃ in a muffle furnace for 3h to obtain MXene-doped ZnO material. Figure 1 As shown, from Figure 1 It can be seen that ZnO grows uniformly on the surface of the MXene layer.

[0045] Example 3

[0046] The NO2 sensor prepared in Example 1 was connected to a multimeter and fixed in a 100 mL sealed chamber. The ratio of nitrogen dioxide to air was adjusted by the gas flow meter of the gas distribution system, and different concentrations of NO2 were introduced into the chamber. The resistance change R of the multimeter was recorded. g After the reaction is completed, pure air is introduced to make the sensor contact with fresh air, the resistance rises, and the recorded resistance returns to the original value R a The above process was repeated at a nitrogen dioxide concentration of 200 ppb. The resistance data collected was exported through the multimeter program to obtain the change value of the resistance signal over time. The time was used as the horizontal axis and the final change value of the resistance signal was compared with the initial value (ΔR / R0) as the vertical axis. Figure 2 ,from Figure 2 It can be seen that the sensor shows a sensitive response to NO2 concentration of 200 ppb.

[0047] The above are only a few embodiments of the present application and do not constitute any form of limitation to the present application. Although the present application is disclosed as above with preferred embodiments, it is not intended to limit the present application. Any technician familiar with the profession, without departing from the scope of the technical solution of the present application, using the technical content disclosed above to make slight changes or modifications are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A method for detecting nitrogen dioxide, characterized in that: The nitrogen dioxide sensor used in the nitrogen dioxide detection method contains MXene-doped ZnO material; The MXene is selected from at least one of an accordion-shaped, a multi-layered, and a single-layered shape.

2. The method for detecting nitrogen dioxide according to claim 1, characterized in that: The preparation method of the MXene-doped ZnO material comprises the following steps: (1) subjecting a mixture containing a zinc ion salt solution, an organic solvent, and an auxiliary agent to ultrasonication and stirring to obtain a sol; (2) After mixing the sol in step (1) and the MXene powder, the mixture is dropped onto a heat-resistant substrate and calcined to obtain the MXene-doped ZnO material.

3. The method for detecting nitrogen dioxide according to claim 2, characterized in that: In the step (1), the zinc ion salt solution is selected from at least one of zinc acetate, zinc nitrate and zinc chloride; Preferably, the concentration of the zinc ion salt solution is 0.01 to 10 g / L; Preferably, the concentration of the zinc ion salt solution is 0.05-1 g / L.

4. The method for detecting nitrogen dioxide according to claim 2, characterized in that: The dosage of the organic solvent, zinc ion salt solution and auxiliary agent is: 100~1000mL: 5~30g: 10~1000μL.

5. The method for detecting nitrogen dioxide according to claim 2, characterized in that: The organic solvent is selected from at least one of ethanol, propanol, isopropanol, carbon tetrachloride and acetone; Preferably, the auxiliary agent is selected from at least one of PVP, PVA, TEOS and ethanolamine.

6. The method for detecting nitrogen dioxide according to claim 2, characterized in that: In the step (2), the amount of the MXene powder is 0.001 to 10 g; Preferably, in step (2), the amount of MXene powder used is 0.01 to 1 g.

7. The method for detecting nitrogen dioxide according to claim 2, characterized in that: In the step (2), the heat-resistant substrate is selected from at least one of alumina, polyimide, and silicon dioxide.

8. The method for detecting nitrogen dioxide according to claim 2, characterized in that: In the step (1), the ultrasonication time is 1 to 12 hours, and the stirring time is 6 to 36 hours.

9. The method for detecting nitrogen dioxide according to claim 2, characterized in that: In the step (2), the conditions for the dripping are: a single dripping amount is 1 to 20 uL, and the number of dripping times is 1 to 10 times.

10. The method for detecting nitrogen dioxide according to claim 2, characterized in that: In the step (2), the calcination temperature is 150 to 600° C., and the calcination time is 1 to 24 hours.

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