Ozone sensing material, preparation method and application thereof

Abstract

This invention relates to the field of gas monitoring technology, specifically to an ozone sensing material, its preparation method, and its application. The ozone sensing material provided by this invention comprises a dual transition metal MXene and SnO2; the synergistic effect between the dual transition metals MXene and SnO2 enables the ozone sensing material to exhibit a large resistance change at low ozone concentrations under room temperature conditions, which corresponds to a significant increase in the sensitivity of the ozone gas sensing element at room temperature, thereby enabling the use of the ozone sensing element at room temperature.

Description

Technical Field

[0001] This invention relates to the field of gas monitoring technology, specifically to an ozone sensing material, its preparation method, and its application. Background Technology

[0002] Ozone (O3), a highly oxidizing air pollutant near the ground, poses a serious threat to human health. Inhalation directly irritates and damages the respiratory tract, inducing oxidative stress and inflammation, potentially leading to respiratory diseases such as asthma and chronic obstructive pulmonary disease (COPD), and is associated with an increased risk of cardiovascular disease. Long-term exposure to environmental ozone has been confirmed by authoritative epidemiological studies to significantly increase the risk of all-cause mortality. The World Health Organization has also clearly pointed out the hazards of ozone. Therefore, ozone pollution is not only a serious environmental problem but also a major public health challenge.

[0003] Gas-sensitive materials commonly used for ozone detection are primarily metal oxides, such as indium oxide and zinc oxide. However, they typically require high temperatures to detect ozone or reach their optimal sensing temperature. Research on room-temperature sensing is limited, and the responsivity is low. For example, In₂O₃ exhibits only a 4% responsivity at 120°C for an air ozone concentration of 0.5 ppm, and only 3.5% at 70°C; ZnO shows only a 3-3.7% responsivity at 250°C for an air ozone concentration of 0.5 ppm, and only 4.2% at 300°C. Therefore, a room-temperature responsive ozone sensing material is needed. Summary of the Invention

[0004] Therefore, the technical problem to be solved by the present invention is to overcome the lack of ozone sensing materials with responsiveness at room temperature in the prior art, thereby providing an ozone sensing material, its preparation method and application.

[0005] In a first aspect, the present invention provides an ozone sensing material comprising a dual transition metal MXene and SnO2.

[0006] In some alternative implementations, the mass ratio of the dual transition metals MXene and SnO2 is (3-7):(0.6-4).

[0007] In some alternative embodiments, the dual transition metal MXene is selected from TiNbCT. x ; where T x Indicates TiNbCT x Surface chemical functional groups include at least one of =O, -OH, and -F.

[0008] In some alternative implementations, TiNbCT xSurface chemical functional groups include =O, -OH, -F, and -Cl.

[0009] In some alternative implementations, TiNbCT x The diameter of a single layer is 200-1000 nm.

[0010] In some alternative embodiments, the ozone sensing material includes TiNbCT. x and SnO2.

[0011] In some alternative embodiments, the 2θ of the XRD of the ozone sensing material has characteristic peaks at 26.5°, 33.8°, 37.9°, 51.7°, and 65.8°; In some alternative embodiments, SnO2 in the ozone sensing material is distributed in TiNbCT x Surface; In some optional embodiments, the XPS detection of the ozone sensing material includes C, O, Ti, Nb, and Sn elements; C 1s peaks at 282, 284.8, 286.6, and 288.8 eV; O 1s peaks at 529.7, 531.5, and 533.3 eV; Ti 2p, Nb 3d, and Sn 3d all show characteristic peaks corresponding to their oxides and carbides; under the same testing conditions, the CO bond binding energy in the C 1s spectrum of the ozone sensing material is higher than that of pure TiNbCT. x Material.

[0012] Secondly, the present invention also provides a method for preparing an ozone sensing material, wherein the ozone sensing material is obtained by mixing and grinding a dispersion containing a dual transition metal MXene with SnO2.

[0013] In some alternative embodiments, the dispersant of the dispersion containing the dual transition metal MXene is water.

[0014] In some alternative embodiments, the grinding temperature is 60-80°C.

[0015] In some optional embodiments, the grinding temperature is 60-80°C; In some alternative embodiments, the grinding time is 10-30 min; as an example, the grinding time is 10 min, 12 min, 16 min, 18 min, 20 min, 25 min or 30 min, or within any of the above values.

[0016] In some alternative embodiments, the concentration of the MXene in the dispersion containing the MXene is 1-10 mg / ml. As an example, the concentration is 1 mg / ml, 2 mg / ml, 3 mg / ml, 4 mg / ml, 5 mg / ml, 6 mg / ml, 7 mg / ml, 8 mg / ml, 9 mg / ml, or 10 mg / ml, or within any range of these values.

[0017] In some alternative embodiments, the mass ratio of MXene to SnO2 in the dispersion containing the dual transition metal MXene is (3-7):(0.6-4). In some alternative embodiments, the mass ratio of MXene to SnO2 in the dispersion containing the dual transition metal MXene is (5-7):(2-4). In some alternative embodiments, the dual transition metal MXene is selected from TiNbCT. x ; where T x Indicates TiNbCT x Surface chemical functional groups include at least one of =O, -OH, and -F.

[0018] In some alternative implementations, TiNbCT x Surface chemical functional groups include =O, -OH, -F, and -Cl.

[0019] In some alternative implementations, TiNbCT x The diameter of a single layer is 200-1000 nm.

[0020] In some alternative implementations, the TiNbCT x The number of layers is N, where N is an integer selected from 1 to 5; In some alternative embodiments, the SnO2 is nanoparticles; In some alternative embodiments, the average particle size of the SnO2 is 30-80 nm. As an example, the average particle size is 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, or 80 nm, or within any range of the above values.

[0021] Thirdly, the present invention also provides an ozone sensing element, including an ozone sensing electrode, wherein the ozone sensing electrode includes a positive electrode and a negative electrode; the positive electrode and the negative electrode are electrically connected through the ozone sensing material described above or the ozone sensing material prepared by the preparation method described above. In some alternative embodiments, the ozone sensing electrode includes interdigitated electrodes.

[0022] Fourthly, the present invention also provides a method for preparing the ozone sensing element described above, comprising the following steps: (1) Provide an ozone sensing electrode, the ozone sensing electrode comprising a positive electrode and a negative electrode; (2) Using an ozone sensing material to connect the positive and negative electrodes, wherein the ozone sensing material is the ozone sensing material described above or the ozone sensing material prepared by the preparation method described above.

[0023] In some alternative embodiments, the process of using ozone sensing material to connect the positive and negative electrodes involves mixing and grinding a dispersion containing a dual transition metal MXene with SnO2 to obtain the ozone sensing material; then dispersing the ozone sensing material in a solvent to obtain a mixed dispersion; placing the dispersion between the positive and negative electrodes, followed by heat treatment.

[0024] In some alternative embodiments, the total concentration of the two transition metals MXene and SnO2 in the mixed dispersion is 0.14-0.19 wt%; as an example, the total concentration is 0.14 wt%, 0.15 wt%, 0.16 wt%, 0.17 wt%, 0.18 wt%, or 0.19 wt%, or within any of the above values.

[0025] In some alternative implementations, the dispersion process is carried out by ultrasonic dispersion.

[0026] In some alternative implementations, the ultrasonic dispersion time is 0.5-1 h.

[0027] In some alternative embodiments, the mass ratio of the two transition metals MXene and SnO2 in the mixed dispersion is (3-7):(0.6-4). In some alternative embodiments, the mass ratio of the two transition metals MXene and SnO2 in the mixed dispersion is (5-7):(2-4); In some alternative embodiments, the solvent is selected from at least one of water and monohydric alcohol; In some alternative embodiments, the monohydric alcohol includes at least one of ethanol or isopropanol; In some alternative embodiments, the dual transition metal MXene is selected from TiNbCT. x ; where T x Indicates TiNbCT x Surface chemical functional groups, including at least one of =O, -OH, and -F; In some alternative implementations, the TiNbCT x The number of layers is N, where N is an integer selected from 1 to 5; In some alternative embodiments, the SnO2 is nanoparticles; In some alternative implementations, the heat treatment temperature is 100-150°C; In some alternative implementations, the heat treatment time is 1-1.5 hours; In some alternative embodiments, the dispersion is placed between the positive and negative electrodes and before heat treatment, including a spin coating process. In some alternative implementations, the heat treatment process also includes a drying process; In some alternative embodiments, the drying temperature is 60-80°C; In some alternative implementations, the drying time is 2-3 hours.

[0028] Fifthly, the present invention also provides a method for detecting ozone, wherein the ozone sensing element described above is placed in an ozone-containing atmosphere; the resistance change of the ozone sensing element is collected, and the ozone concentration or sensitivity is calculated based on the resistance change value.

[0029] In some alternative embodiments, the temperature for detecting ozone is 25-300°C; said temperature is 25°C, 30°C, 40°C, 50°C, 60°C, 65°C, 80°C, 100°C, 120°C, 150°C, 180°C, 200°C, 250°C, or 300°C, or within any range of the above values.

[0030] In some alternative embodiments, the atmosphere is selected from air or nitrogen; In some alternative embodiments, the atmosphere is selected from air, and the minimum ozone concentration in the ozone-containing atmosphere is 46 ppb. In some alternative embodiments, the atmosphere is selected from nitrogen, and the minimum ozone concentration in the ozone-containing atmosphere is 57 ppb. In some alternative implementations, the detection uses ultraviolet light to irradiate the ozone sensing material in the ozone sensing element.

[0031] In some alternative embodiments, when the ozone sensing element is irradiated with ultraviolet light in an air atmosphere, the minimum ozone concentration in the ozone-containing atmosphere is 31.2 ppb.

[0032] Fifthly, the present invention also provides the application of the ozone sensing material described above, or the preparation method described above, or the ozone sensing element described above, or the ozone sensing element prepared by the preparation method described above, in a room temperature ozone sensor.

[0033] The technical solution of this invention has the following advantages: The present invention provides an ozone sensing material comprising a dual transition metal MXene and SnO2; wherein the synergistic effect between the dual transition metal MXene and SnO2 enables the ozone sensing material to exhibit a large resistance change at low ozone concentrations under room temperature conditions, which corresponds to a significant increase in the sensitivity of the ozone gas sensing element at room temperature conditions, thereby enabling the use of the ozone sensing element at room temperature conditions.

[0034] Furthermore, the ozone sensing material provided by this invention has stable properties, and its sensitivity to ozone decreases only slightly during long-term use, thereby improving the stability and lifespan of sensors using this material and reducing maintenance costs. Attached Figure Description

[0035] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0036] Figure 1 The XRD test spectra of the ozone sensing material between the positive and negative electrodes of the ozone sensing elements in Examples 1-3 and Comparative Examples 1-2 are shown. Figure 2 SEM images of the ozone sensing material between the positive and negative electrodes of the ozone sensing elements in Example 2, Comparative Example 1, and Comparative Example 2; Figure 3 XPS characterization spectra of the ozone sensing material between the positive and negative electrodes of the ozone sensing element in Example 2 and Comparative Example 1; Figure 4 The graphs show the sensitivity relationships of the ozone sensing elements in Examples 1-3 and Comparative Examples 1-2 under different carrier gases and ozone concentrations. Figure 5 This is a graph showing the sensitivity relationship of the ozone sensing element in Example 2 under different carrier gases and low concentrations of ozone. Figure 6 This is a dynamic sensitivity test diagram of the ozone sensing element in Example 2 under different carrier gases and ozone cycles of different concentrations; Figure 7 This is a dynamic sensitivity test diagram of the ozone sensing element in Example 2 under different carrier gases and the same concentration of ozone cycling. Figure 8 The diagram shows the dynamic sensitivity test of the ozone sensing element in Example 2 under different carrier gases and ozone cycles of different concentrations under ultraviolet light irradiation. Figure 9A graph showing the relationship between ozone concentration and the sensitivity of the ozone sensing element in Example 2, with air as the carrier gas and ultraviolet light assistance. Figure 10 The diagram shows the dynamic sensitivity test of the ozone sensing element in Example 2 under different carrier gases and the same concentration of ozone under ultraviolet light irradiation. Figure 11 The graph shows the sensitivity relationship of the ozone sensing element in Example 2 under different carrier gases and low concentrations of ozone under ultraviolet light irradiation. Figure 12 The graph shows the resistance change of the ozone sensing element in Example 2 under ultraviolet light irradiation and non-ultraviolet light irradiation conditions at an ozone concentration of 350 ppb in the air. Figure 13 The graph shows the sensitivity response time and related performance test results of the ozone sensing element in Example 2. Figure 14 This is a graph showing the gas selectivity test results of the ozone sensing element in Example 2. Detailed Implementation

[0037] The following embodiments are provided to better understand the present invention and are not limited to the preferred embodiments described. They do not constitute a limitation on the content and scope of protection of the present invention. Any product that is the same as or similar to the present invention, derived by any person under the guidance of the present invention or by combining the features of the present invention with other prior art, falls within the protection scope of the present invention.

[0038] For experiments not specifically described in the examples, the procedures or conditions should be followed according to the conventional experimental procedures described in the literature in this field. Reagents or instruments whose manufacturers are not specified are all commercially available conventional reagent products.

[0039] The TiNbCT used in the embodiments and comparative examples of this application x Purchased from Foshan Xinxi Technology Co., Ltd., the product is a 5 mg / ml aqueous dispersion with 5 or fewer layers, a single layer diameter of 200-1000 nm, and surface groups including =O, -OH, -F, and -Cl.

[0040] The SnO2 used in the embodiments and comparative examples of this application was purchased from Ningbo Yumu New Materials Co., Ltd., and the model is 50 nm nanoparticles.

[0041] The Ti3C2 used in the comparative examples of this application was purchased from Foshan Xinxi Technology Co., Ltd., and the product was a 5 mg / ml dispersion.

[0042] The interdigitated electrodes used in the embodiments and comparative examples of this application are silicon-based interdigitated electrodes (the width of the interdigitated electrode is 5 mm, the effective length of the interdigitated fingers is 8 mm, the material of the interdigitated electrode is Au with a purity of 99.99%; the electrode spacing is 20 μm, and the number of electrode pairs is 20).

[0043] Unless otherwise stated, all performance tests in this application were conducted at room temperature, which refers to 25°C.

[0044] In this application, the concepts of background gas and carrier gas are interchangeable.

[0045] Example 1 This embodiment provides an ozone sensing element, the preparation method of which includes the following steps: (1) Provide interdigitated electrodes; the interdigitated electrodes include a positive electrode and a negative electrode, and the interdigitated electrodes are placed on an insulating substrate; (2) TiNbCT x SnO2 was mixed at a mass ratio of 5:2, then ground at 80℃ for 20 min, and then mixed with water and ultrasonically dispersed for 0.5 h to form a mixed dispersion (TiNbCT in the mixed dispersion). x The total concentration of SnO2 is 0.15wt%). 25μL of the mixed dispersion is dropped between the positive and negative electrodes, and then spin-coated at 300 r / min for 5s on a spin coater. The electrodes are then heat-treated at 120℃ for 1 hour, and then dried at 70℃ for 3 hours to obtain the ozone sensing element.

[0046] Example 2 (1) Provide interdigitated electrodes; the interdigitated electrodes include a positive electrode and a negative electrode, and the interdigitated electrodes are placed on an insulating substrate; (2) TiNbCT x SnO2 was mixed at a mass ratio of 5:3, then ground at 80℃ for 20 min, and then mixed with water and ultrasonically dispersed for 0.5 h to form a mixed dispersion (TiNbCT in the mixed dispersion). x The total concentration of SnO2 is 0.15wt%). 25μL of the mixed dispersion is dropped between the positive and negative electrodes, and then spin-coated at 300 r / min for 5s on a spin coater. The electrodes are then heat-treated at 120℃ for 1 hour, and then dried at 70℃ for 3 hours to obtain the ozone sensing element.

[0047] Example 3 (1) Provide interdigitated electrodes; the interdigitated electrodes include a positive electrode and a negative electrode, and the interdigitated electrodes are placed on an insulating substrate; (2) TiNbCT xSnO2 was mixed at a mass ratio of 5:4, then ground at 80℃ for 20 min, and then mixed with water and ultrasonically dispersed for 0.5 h to form a mixed dispersion (TiNbCT in the mixed dispersion). x The total concentration of SnO2 is 0.15wt%). 25μL of the mixed dispersion is dropped between the positive and negative electrodes, and then spin-coated at 300 r / min for 5s on a spin coater. The electrodes are then heat-treated at 120℃ for 1 hour, and then dried at 70℃ for 3 hours to obtain the ozone sensing element.

[0048] Comparative Example 1 This comparative example provides an ozone sensing element, the preparation method of which includes the following steps: (1) Provide interdigitated electrodes; the interdigitated electrodes include a positive electrode and a negative electrode, and the interdigitated electrodes are placed on an insulating substrate; (2) TiNbCT x The mixture was ground at 80℃ for 20 min, then mixed with water and ultrasonically dispersed for 0.5 h to form a mixed dispersion (TiNbCT in the mixed dispersion). x The concentration of the mixture is 0.15 wt%). 25 μL of the mixed dispersion is dropped between the positive and negative electrodes, and then spin-coated at 300 r / min for 5 s on a spin coater. After that, it is heat-treated at 120℃ for 1 hour, and then dried at 70℃ for 3 hours to obtain the ozone sensing element.

[0049] Comparative Example 2 This comparative example provides an ozone sensing element, the preparation method of which includes the following steps: (1) Provide interdigitated electrodes; the interdigitated electrodes include a positive electrode and a negative electrode, and the interdigitated electrodes are placed on an insulating substrate; (2) SnO2 was ground at 80℃ for 20 min, and then mixed with water and ultrasonically dispersed for 0.5 h to form a mixed dispersion (the concentration of SnO2 in the mixed dispersion was 0.15 wt%). 25 μL of the mixed dispersion was dropped between the positive and negative electrodes, and then spin-coated at 300 r / min for 5 s on a spin coater. After that, it was heat-treated at 120℃ for 1 hour, and then dried at 70℃ for 3 h to obtain the ozone sensing element.

[0050] Comparative Example 3 This comparative example provides an ozone sensing element, the preparation method of which includes the following steps: (1) Provide interdigitated electrodes; the interdigitated electrodes include a positive electrode and a negative electrode, and the interdigitated electrodes are placed on an insulating substrate; (2) Ti3C2 and SnO2 are mixed at a mass ratio of 5:3, then ground at 80°C for 20 min, and then mixed with water and ultrasonically dispersed for 0.5 h to form a mixed dispersion (the total concentration of Ti3C2 and SnO2 in the mixed dispersion is 0.15wt%). 25 μL of the mixed dispersion is dropped between the positive and negative electrodes, and then spin-coated at 300 r / min for 5 s on a spin coater. After that, it is heat-treated at 120°C for 1 hour, and then dried at 70°C for 3 h to obtain the ozone sensing element.

[0051] Test case 1. XRD Testing XRD tests were performed on the ozone sensing material between the positive and negative electrodes of the ozone sensing elements in Examples 1-3 and Comparative Examples 1-2. The test results are as follows: Figure 1 As shown, the main peaks of the ozone sensing material at 2θ = 26.5, 33.8, 37.9, 51.7, and 65.8 are located on the (110), (101), (200), (211), and (301) crystal planes, respectively.

[0052] 2. SEM characterization SEM images of the ozone sensing material between the positive and negative electrodes of the ozone sensing element in Example 2, Comparative Example 1, and Comparative Example 2 are shown below. Figure 2 As shown, where Figure 2 -a is the SEM image of the ozone sensing material in Comparative Example 1; Figure 2 -b is the SEM image of the ozone sensing material in Comparative Example 2; Figure 2 -c is the SEM image of the ozone sensing material in Example 2.

[0053] 3. XPS characterization XPS characterization was performed on the ozone sensing material between the positive and negative electrodes of the ozone sensing elements in Example 2 and Comparative Example 1. The detected chemical elements were C, O, Ti, Nb, and Sn, respectively. Figure 3 As shown; Figure 3 -a shows the spectrum of the ozone sensing material between the positive and negative electrodes of the ozone sensing element in Example 2. Figure 3 -b represents the C 1s high-resolution spectra of Example 2 and Comparative Example 1, which are mainly divided into four peaks at 288.8, 286.6, 284.8 and 282 eV, corresponding to CO, C=O, CC and C-Nb bonds, respectively. In Example 2, the binding energy of CO bonds in the ozone sensing material is increased, indicating that the composite process has a certain impact on the surface functional groups. Figure 3 -c shows the O 1s high-resolution spectra of Example 2 and Comparative Example 1, where the peaks are 533.3, 531.5, and 529.7 eV, respectively, corresponding to Ti-OH and TiO2. xAnd TiO2 bond; the results show that TiO x The peak values ​​of SnO2 and TiO2 showed a significant increase, indicating that the introduction of SnO2 increased the content of adsorbed oxygen and that adsorbed oxygen on the surface tended to form more active sites, thereby enhancing the sensing capability. Figure 3 -d represents the spectrum of the ozone sensing material in Example 2, which consists of four double peaks, mainly distributed at 457.8, 456.9, 455.2, and 453.7 eV, corresponding to TiO2, Ti-C, Ti-X, and Ti, respectively. x O y . Figure 3 -e represents the spectrum of the ozone sensing material in Example 2, showing three doublets of Nb 3d, mainly at 205.9, 203.6, and 202.5 eV, corresponding to Nb2O5, NbO2, and NbC, respectively. x . Figure 3 -f shows two distinct peaks in Sn 3d. 5 / 2 Corresponding to 494.2, Sn 3d 3 / 2 This corresponds to 485.6 eV.

[0054] 4. Sensitivity test of gas sensing element The positive and negative electrodes of the ozone sensing elements prepared in Examples 1-3 and Comparative Examples 1-3 were connected to leads, and then resistance tests were performed in the test atmosphere. The sensitivity of the ozone sensing element was calculated based on the resistance change, using the following formula: S =ΔR / R 0×100%(ΔR=( R g –R 0)) in S It refers to the sensitivity of the gas sensing element. R 0 represents the resistance of the sensing element in the carrier gas. R g The resistance of the sensing element in the target gas.

[0055] 4.1 Static Testing: Under room temperature conditions, the sensitivity of the gas sensing element was tested under different ozone concentrations, using air and nitrogen as carrier gases respectively. The sensitivity of the gas sensing element was tested for ozone concentrations of 500, 800, 1000, and 5000 ppb; the test results are shown in Tables 1 and 2. Table 1 shows the sensitivity of the gas sensing element under the condition of air as the carrier gas; Table 2 shows the sensitivity of the gas sensing element under the condition of nitrogen as the carrier gas.

[0056] Table 1

[0057] / indicates that no test was performed. Table 2

[0058] / indicates that no test was performed. 4.2 Dynamic Testing 4.2.1 Relationship between concentration and ozone sensor sensitivity The resistance of the ozone sensing element in Examples 1-3 and Comparative Examples 1-2 was measured as the ozone concentration changed from 0.5-5 ppm in different carrier gases (the time for the change from 0.5-0.8 ppm was 5 s, the time for the change from 0.8-1 ppm was 5 s, and the time for the change from 1-5 ppm was 5 s), and converted into the sensitivity of the ozone sensing element. Figure 4 -a is a graph showing the relationship between ozone concentration and the sensitivity of ozone sensing element under the condition that air is the carrier gas. Figure 4 -b is a graph showing the relationship between ozone concentration and the sensitivity of the ozone sensing element under nitrogen as the carrier gas condition.

[0059] Experimental results show that the device's responsivity increases with increasing ozone concentration under different background gases. The responsivity in air is significantly higher than in nitrogen, because ozone extracts electrons from the conduction band or surface oxygen atoms of the composite material, thus reducing the carrier concentration. Specifically, adsorbed O3 undergoes redox reactions with active sites such as surface metal atoms, oxygen vacancies, and adsorbed oxygen, while in nitrogen, O3 only reacts with surface metal atoms and oxygen vacancies. This leads to changes in the electronic structure of the material surface and consequently, changes in the material's electrical resistance.

[0060] 4.2.2 Detection Limit Test In Example 2, the resistance of the ozone sensing element was measured as the ozone concentration varied from 0.1 to 0.35 ppm in different carrier gases (the time for the changes was 5 s for 0.1-0.195 ppm, 0.195-0.285 ppm, and 0.285-0.35 ppm), and converted into the sensitivity of the ozone sensing element. Figure 5 -a is a graph showing the relationship between ozone concentration and the sensitivity of ozone sensing element under the condition that air is the carrier gas. Figure 5 -b is a graph showing the relationship between ozone concentration and the sensitivity of the ozone sensor element under nitrogen as the carrier gas condition: the detection limits for ozone in air and N2 environments are 46 ppb and 57 ppb, respectively.

[0061] 4.2.3 Dynamic sensitivity detection during cycling at different concentrations Dynamic sensitivity tests were conducted on the ozone sensing element described in Example 2 using air and nitrogen as carrier gases: A target gas of 100 ppb was introduced, and after the resistance stabilized, the resistance change was measured and the sensitivity was calculated; then, the carrier gas was switched, and the resistance was allowed to stabilize again. The same method was used to test target gases of 195 ppb, 285 ppb, and 350 ppb. The test results are as follows. Figure 6 As shown.

[0062] 4.23 Dynamic sensitivity detection during cycling at the same concentration Using air as the carrier gas, the ozone sensing element of Example 2 was tested: a target gas of 350 ppb was introduced, and after the resistance stabilized, the resistance change was measured and the sensor sensitivity was calculated; then, the carrier gas was switched, and the resistance was allowed to stabilize again. This process was repeated four times, and the test results are as follows. Figure 7 As shown.

[0063] Using nitrogen as the carrier gas, the ozone sensing element of Example 2 was subjected to dynamic sensitivity testing according to the same method, except that the carrier gas was replaced with nitrogen. All other test conditions and procedures remained the same. The test results are as follows: Figure 7 As shown.

[0064] As can be seen from the figure, the device exhibits good repeatability in both air and nitrogen environments at an ozone concentration of 350 ppb, indicating that it can be applied in different scenarios.

[0065] 4.3 Dynamic Cyclic Test of Ultraviolet Irradiation 4.3.1 Dynamic sensitivity detection during cycling at different concentrations Ultraviolet light was directly irradiated onto the surface of the gas-sensitive material (ultraviolet light source power 15 mW, distance between ultraviolet light source and gas-sensitive material surface 15 cm). Dynamic sensitivity tests were performed on the ozone sensing element described in Example 2 using air and nitrogen as carrier gases: 100 ppb target gas was introduced, and after the resistance stabilized, the resistance change was measured and the sensitivity was calculated; then the carrier gas was switched, and the resistance was allowed to stabilize again. The same method was used to complete the tests for 195 ppb, 285 ppb, and 350 ppb target gases, and the test results are shown in Figure 8. Figure 9 The graph shows the relationship between ozone concentration and the sensitivity of the ozone sensor element under ultraviolet light assistance with air as the carrier gas. The detection limit is 31.2 ppb.

[0066] 4.3.2 Dynamic sensitivity detection during cycling at the same concentration Ultraviolet light was directly irradiated onto the surface of the gas-sensitive material (UV light source power 15 mW, distance between UV light source and gas-sensitive material surface 15 cm). Using air as the carrier gas, the ozone sensing element of Example 2 was tested: 350 ppb of target gas was introduced, and after the resistance stabilized, the resistance change was measured and the sensor sensitivity was calculated; then the carrier gas was switched, and the resistance was allowed to stabilize again. The above process was repeated 5 times, and the test results are shown in Figure 10.

[0067] Using nitrogen as the carrier gas, the ozone sensing element of Example 2 was subjected to dynamic sensitivity testing according to the same method, except that the carrier gas was replaced with nitrogen. All other test conditions and procedures remained the same. The test results are as follows: Figure 10 As shown.

[0068] 4.3.2 Relationship between concentration and ozone sensor sensitivity Ultraviolet light was directly irradiated onto the surface of the gas-sensitive material (UV light source power 15 mW, distance between UV light source and gas-sensitive material surface 15 cm). The resistance of the ozone sensing element in Example 2 was measured as the ozone concentration changed from 0.1 to 0.35 ppm in different carrier gases (time for changes from 0.1 to 0.195 ppm was 5 s, from 0.195 to 0.285 ppm was 5 s, and from 0.285 to 0.35 ppm was 5 s). This resistance was then converted into the sensitivity of the ozone sensing element. The test results are as follows: Figure 11 As shown.

[0069] 4.3.3 Effect of UV light on electrical resistance under stable concentration conditions The resistance change of the ozone sensing element in Example 2 was measured under ultraviolet and non-ultraviolet irradiation conditions when the ozone concentration in the air was 350 ppb. The test results are as follows: Figure 12 As shown, the resistance decreases when the device is irradiated with ultraviolet light.

[0070] 4.4 Sensitivity Response Time At a certain temperature, carrier gas is introduced into the test chamber. After the resistance stabilizes, ozone of the target concentration is introduced, causing the resistance to rise. Once the resistance reaches its highest stable value, the ozone channel is closed, and carrier gas is introduced again, causing the resistance to decrease. Once the resistance stabilizes, a set of tests is complete. Figure 13 -a is the ozone single-cycle test of the ozone sensing material in Example 2 at room temperature (25°C) with an ozone concentration of 195 ppb. The response time is 476 s and the recovery time is 439 s. Figure 13 -b represents the temperature variation test of the ozone sensing material in Example 2 at a concentration of 5 ppm ozone, ranging from 25°C to 65°C. It can be seen that the responsiveness of the device gradually increases with increasing temperature. Figure 13-c represents the test results of the ozone sensing material in Example 2 under an ozone concentration of 350 ppb (carrier gas is air) for 2 days. Its responsivity decreased slightly but remained basically at the same level. Figure 13 -d is the test result graph of the ozone sensing material in Example 2 at humidity of 45% and 65% and ozone concentration of 500 ppb (carrier gas is air). It can be seen that the response decreases slightly as the humidity increases.

[0071] 4.5 Gas sensitivity selectivity test The test used air as the background gas. The ozone sensing material prepared in Example 2 was tested for its ozone sensing element sensitivity at a pollutant gas concentration (methanol, ethanol, benzene, acetonitrile, isopropanol) of 1 ppm. The results are as follows: Figure 14 As shown, where Figure 14 -a represents the sensitivity result of the ozone sensing element. Figure 14 -b shows the gas adsorption distance calculated using Materials Studios software; the results of the gas adsorption energy simulated using Materials Studios software are shown in Table 3.

[0072] Table 3 Adsorption energies of different gases

[0073] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. An ozone sensing material, characterized in that, Including dual transition metals MXene and SnO2.

2. The ozone sensing material according to claim 1, characterized in that, The mass ratio of the two transition metals MXene to SnO2 is (3-7):(0.6-4). Preferably, the dual transition metal MXene is selected from TiNbCT. x ; where T x TiNbCT x Surface chemical functional groups include at least one of =O, -OH, and -F.

3. A method for preparing an ozone sensing material, characterized in that, The ozone sensing material is obtained by mixing and grinding a dispersion containing the dual transition metal MXene with SnO2.

4. The preparation method according to claim 3, characterized in that, The grinding temperature is 60-80℃; Preferably, the grinding time is 10-30 minutes; Preferably, the concentration of the dual transition metal MXene in the dispersion is 1-10 mg / ml.

5. The preparation method according to claim 3 or 4, characterized in that, The mass ratio of MXene to SnO2 in the dispersion containing the dual transition metal MXene is (3-7):(0.6-4). More preferably, the mass ratio of MXene to SnO2 in the dispersion containing the dual transition metal MXene is (5-7):(2-4). Preferably, the dual transition metal MXene is selected from TiNbCT. x ; where T x TiNbCT x Surface chemical functional groups, including at least one of =O, -OH, and -F; Preferably, the TiNbCT x The number of layers is N, where N is an integer selected from 1 to 5; Preferably, the SnO2 is in the form of nanoparticles; More preferably, the average particle size of the SnO2 is 30-80 nm.

6. An ozone sensing element, characterized in that, The device includes an ozone sensing electrode, which comprises a positive electrode and a negative electrode; the positive electrode and the negative electrode are electrically connected by an ozone sensing material as described in claim 1 or 2 or an ozone sensing material prepared by any one of the preparation methods described in claims 3-5. Preferably, the ozone sensing electrode includes an interdigitated electrode.

7. A method for preparing the ozone sensing element according to claim 6, characterized in that, Includes the following steps: (1) Provide an ozone sensing electrode, the ozone sensing electrode comprising a positive electrode and a negative electrode; (2) Using an ozone sensing material to connect the positive and negative electrodes, wherein the ozone sensing material is the ozone sensing material according to claim 1 or 2 or the ozone sensing material prepared by the preparation method according to any one of claims 3-5; Preferably, the process of using ozone sensing material to connect the positive and negative electrodes involves mixing and grinding a dispersion containing the dual transition metal MXene with SnO2 to obtain the ozone sensing material; then dispersing the ozone sensing material in a solvent to obtain a mixed dispersion; placing the dispersion between the positive and negative electrodes, followed by heat treatment.

8. The preparation method according to claim 7, characterized in that, The total concentrations of the two transition metals MXene and SnO2 in the mixed dispersion were 0.14–0.19 wt%. Preferably, the mass ratio of the two transition metals MXene and SnO2 in the mixed dispersion is (3-7):(0.6-4). More preferably, the mass ratio of the two transition metals MXene and SnO2 in the mixed dispersion is (5-7):(2-4); Preferably, the solvent is selected from at least one of water and monohydric alcohol; Preferably, the monohydric alcohol includes at least one of ethanol or isopropanol; Preferably, the dual transition metal MXene is selected from TiNbCT. x ; where T x TiNbCT x Surface chemical functional groups, including at least one of =O, -OH, and -F; Preferably, the TiNbCT x The number of layers is N, where N is an integer selected from 1 to 5; Preferably, the SnO2 is in the form of nanoparticles; Preferably, the heat treatment temperature is 100-150℃; Preferably, the heat treatment time is 1-1.5 hours; Preferably, the process of spin coating is included after the dispersion is placed between the positive and negative electrodes and before heat treatment; Preferably, the heat treatment also includes a drying process; Preferably, the drying temperature is 60-80°C; Preferably, the drying time is 2-3 hours.

9. A method for detecting ozone, characterized in that, The ozone sensing element of claim 6 is placed in an ozone-containing atmosphere; the resistance change of the ozone sensing element is collected, and the ozone concentration or sensitivity is calculated based on the resistance change value. Preferably, the temperature for ozone detection is 25-300℃; Preferably, the atmosphere is selected from air or nitrogen; Preferably, the atmosphere is selected from air, and the minimum ozone concentration in the ozone-containing atmosphere is 46 ppb; Preferably, the atmosphere is selected from nitrogen, and the minimum ozone concentration in the ozone-containing atmosphere is 57 ppb; Preferably, the ozone sensing material in the ozone sensing element is irradiated with ultraviolet light during detection.

10. The application of the ozone sensing material according to claim 1 or 2, or the preparation method according to any one of claims 3-5, or the ozone sensing element according to claim 6, or the ozone sensing element prepared by the preparation method according to claim 7 or 8, in a room temperature ozone sensor.

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