Gas sensing material, preparation method thereof and application of gas sensing material in sensor

Abstract

The invention discloses a gas sensing material as well as a preparation method and application thereof in a sensor, the gas sensing material is a metal organic framework material with a one-dimensional coordination structure, and the metal organic framework material comprises a complex of metal and an organic ligand; wherein the metal comprises one of copper, nickel and cobalt, the organic ligands comprise tetra-substituted benzene and tetra-substituted polycyclic aromatic hydrocarbon, substituent groups are hydroxyl or amido, every two of the four substituent groups serve as a group, and each group is arranged in an ortho-position mode; and the two groups are arranged in a central symmetry manner. According to the invention, the gas sensing sensitivity of the sensor in an oxygen-free environment is improved, and the sensitivity and selectivity of the sensor to adsorbed gas and the conductivity of the metal organic framework material are improved; the yield of the metal organic framework material is improved by regulating and controlling the microstructure and the gas sensing performance of the metal organic framework material.

Description

Technical Field

[0001] The invention belongs to the technical field of gas sensors, and in particular relates to a gas sensing material and a preparation method thereof and an application in a sensor. Background Art

[0002] As global energy and environmental issues continue to intensify, new energy vehicles (NEVs) are developing rapidly as one of the areas of sustainable development. As one of its key components, NEV batteries have undergone rapid innovation and promoted breakthroughs in electric vehicle technology. However, battery safety issues have attracted attention, including thermal runaway, explosion and fire. Therefore, it is crucial to study and develop more effective methods for detecting and preventing battery thermal runaway. At present, the scientific research community has proposed a series of means, such as infrared thermal imaging, temperature and pressure sensors, but there are limitations. Researchers recognize that battery thermal runaway will produce gases, and detecting these gases can provide more accurate judgments and early warnings. Therefore, gas detection-based methods have potential for monitoring and early warning applications of thermal runaway. Using sensors to monitor battery status in real time and early warning and take measures can reduce the safety risk of thermal runaway. However, existing metal oxide sensors usually require oxygen participation, which limits their application in detecting gas generated by battery thermal runaway under oxygen-free conditions in battery packs. Therefore, it is urgent to develop new materials and sensors that can work stably under non-oxygen conditions and accurately detect gas generated by battery thermal runaway.

[0003] Metal-organic framework materials (MOFs) are emerging materials with unique properties and potential applications. MOFs are composed of metal ions and organic ligands to form an ordered pore structure. Their high specific surface area, adjustable pore structure, diverse chemical composition and customized synthesis methods give them advantages. At the same time, MOFs have adjustable surface properties and chemical reactivity, making them ideal gas sensing materials. The mechanism of MOFs as gas-sensitive materials is based on coordinated electron transfer. The adsorption of gas molecules will lead to the formation or breakage of coordination bonds, causing electron transfer, thereby changing the electrical and optical properties of MOFs, achieving sensitivity and selectivity to adsorbed gases, so it has the potential to detect gases under non-oxygen conditions.

[0004] In general, one-dimensional quantum confinement and structural anisotropy can lead to unique physical phenomena. In recent years, nanomaterials based on one-dimensional building blocks have attracted much attention due to their high structural regularity, chemically modular edges, and tunable structure-activity relationships. One-dimensional MOFs have higher structural freedom than two-dimensional and three-dimensional MOFs, providing more opportunities for creating conductive pathways. Therefore, it is crucial to solve the problem of gas sensing materials being able to respond to gases under non-oxygen conditions. Summary of the invention

[0005] The purpose of this section is to summarize some aspects of embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the specification abstract and the invention title of this application to avoid blurring the purpose of this section, the specification abstract and the invention title, and such simplifications or omissions cannot be used to limit the scope of the present invention.

[0006] In view of the above problems and / or the problems existing in the prior art, the present invention is proposed.

[0007] Therefore, the object of the present invention is to overcome the deficiencies in the prior art and provide a gas sensing material.

[0008] In order to solve the above technical problems, the present invention provides the following technical solutions: a gas sensing material, characterized in that: the gas sensing material is a metal organic framework material with a one-dimensional coordination structure, and the metal organic framework material includes a complex of a metal and an organic ligand;

[0009] Among them, the metal includes one of copper, nickel, and cobalt, the organic ligand includes tetrasubstituted benzene and tetrasubstituted condensed aromatic hydrocarbons, the substituents are hydroxyl groups or amine groups, the four substituents are grouped in two, each group is arranged in ortho positions, and the two groups are arranged in a central symmetric manner.

[0010] As a preferred embodiment of the preparation method of the present invention, the organic ligand includes 1,2,4,5-tetrasubstituted benzene, 2,3,6,7-tetrasubstituted naphthalene, 1,2,5,6-tetrasubstituted naphthalene, 2,3,6,7-tetrasubstituted anthracene, 1,2,5,6-tetrasubstituted anthracene, wherein R is a hydroxyl group or an amino group.

[0011] As a preferred embodiment of the preparation method of the present invention, the response gas of the gas sensing material includes one or more of carbon monoxide, ammonia and hydrogen sulfide.

[0012] Another object of the present invention is to overcome the deficiencies in the prior art and provide a method for preparing a gas sensing material.

[0013] As a preferred embodiment of the preparation method of the present invention, the metal ion solution is added dropwise to the organic ligand solution, and after uniform mixing, the mixture is stirred for reaction to obtain the gas sensing material.

[0014] As a preferred embodiment of the preparation method of the present invention, the stirring reaction time is 24 hours and the temperature is 25-60°C.

[0015] As a preferred embodiment of the preparation method of the present invention, the organic ligand solution includes tetrasubstituted benzene and tetrasubstituted condensed aromatic hydrocarbon solutions, and the metal ion solution includes divalent copper ion solution, divalent nickel ion solution and divalent cobalt ion solution.

[0016] As a preferred embodiment of the preparation method of the present invention, the molar ratio of the organic ligand to the metal ion is 1:1-4.

[0017] As a preferred embodiment of the preparation method of the present invention, the metal ion solution includes a divalent metal salt solution, and the divalent metal salt includes hydrated acetate, hydrated sulfate, and hydrated chloride.

[0018] As a preferred embodiment of the preparation method of the present invention, the solvent of the organic ligand solution includes one or more of methanol, ethanol, acetone, N,N-dimethylformamide and chloroform.

[0019] Another object of the present invention is to overcome the deficiencies in the prior art and provide an application of a gas sensing material in a sensor.

[0020] Beneficial effects of the present invention:

[0021] The present invention improves the sensing sensitivity of the sensor to gas in an oxygen-free environment, improves the sensitivity and selectivity to adsorbed gas and the conductivity of the metal organic framework material; and improves the yield of the metal organic framework material by regulating the microstructure and gas sensing performance of the metal organic framework material. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative labor. Among them:

[0023] Figure 1 Schematic diagram of the method for preparing the gas sensing material of the present invention.

[0024] Figure 2 This is a schematic diagram of the synthesis principle of the gas sensing material in Example 1 of the present invention.

[0025] Figure 3 Schematic diagram of a gas sensor according to an embodiment of the present invention.

[0026] Figure 4 Schematic diagram of gas sensing performance test according to an embodiment of the present invention.

[0027] Figure 5 This is the X-ray diffraction pattern (XRD) of the gas sensing material according to the embodiment of the present invention.

[0028] Figure 6 This is a scanning electron microscope (SEM) image of the gas sensing material CuBTA-1 obtained in Example 1 of the present invention.

[0029] Figure 7 This is a schematic diagram of the concentration gradient response of the gas sensing material CuBTA-1 obtained in Example 1 of the present invention to CO.

[0030] Figure 8 This is a schematic diagram of the cyclic response of the gas sensing material CuBTA-1 obtained in Example 1 of the present invention to 50 ppm CO.

[0031] Fig. 9 Schematic diagram of the selectivity of the gas sensing material CuBTA-1 obtained in Example 1 of the present invention to 50 ppm gas. DETAILED DESCRIPTION

[0032] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the embodiments of the specification.

[0033] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0034] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0035] Unless otherwise specified, all raw materials used in the examples of the present invention are commercially available, as shown in Table 1 for details.

[0036] Table 1

[0037]

[0038]

[0039] The chemical formula of 1,2,4,5-tetrasubstituted benzene in the organic ligand is shown in formula (1), the chemical formula of 2,3,6,7-tetrasubstituted naphthalene is shown in formula (2), the chemical formula of 1,2,5,6-tetrasubstituted naphthalene is shown in formula (3), the chemical formula of 2,3,6,7-tetrasubstituted anthracene is shown in formula (4), and the chemical formula of 1,2,5,6-tetrasubstituted anthracene is shown in formula (5); wherein R is a hydroxyl group or an amino group.

[0040]

[0041]

[0042] Example 1

[0043] (1) Weigh 28.40 mg (0.10 mmol) of 1,2,4,5-benzenetetramine (BTA) ligand and 40.00 mg (0.20 mmol) of copper acetate monohydrate;

[0044] The BTA ligand was dissolved in 5 mL of N,N-dimethylformamide (DMF), and ultrasonicated for 10 min using an ultrasonic machine to dissolve the organic ligand to obtain a BTA ligand solution; 40.00 mg of cupric acetate monohydrate was dissolved in 5 mL of deionized water, and stirred thoroughly to dissolve it to obtain a divalent copper ion solution.

[0045] (2) Slowly drip the cupric acetate solution into the BTA ligand solution, and use an ultrasonic machine to sonicate for 10 minutes to make the mixed solution uniform.

[0046] (3) The mixed solution was placed in a 30 mL screw-cap glass bottle, a magnetic stirrer was added, the bottle cap was tightened, and the reaction was stirred at room temperature (25°C) for 24 h.

[0047] (4) After the reaction, the obtained black precipitate was washed alternately by centrifugation with deionized water and ethanol at a centrifugal speed of 8000 rpm for 10 min. It was then dried in an oven at 60°C for 6 h to obtain the MOFs material CuBTA-1.

[0048] Figure 1 Schematic diagram of the preparation method of the gas sensing material of the present invention; Figure 2 This is a schematic diagram of the synthesis principle of the gas sensing material in Example 1 of the present invention.

[0049] Example 2

[0050] The difference from Example 1 is that the 1,2,4,5-benzenetetramine (BTA) ligand in step (1) is replaced by 1,2,4,5-tetrahydroxybenzene (BTH) to obtain the MOFs material CuBTH.

[0051] Example 3

[0052] The difference from Example 1 is that the 1,2,4,5-benzenetetramine (BTA) ligand in step (1) is replaced by 2,3,6,7-tetraaminonaphthalene (NTA1) to obtain the MOFs material CuNTA1.

[0053] Example 4

[0054] The difference from Example 1 is that the 1,2,4,5-benzenetetramine (BTA) ligand in step (1) is replaced by 2,3,6,7-tetrahydroxynaphthalene (NTH1) to obtain the MOFs material CuNTH1.

[0055] Example 5

[0056] The difference from Example 1 is that the 1,2,4,5-benzenetetramine (BTA) ligand in step (1) is replaced by 1,2,5,6-tetraaminonaphthalene (NTA2) to obtain the MOFs material CuNTA2.

[0057] Example 6

[0058] The difference from Example 1 is that the 1,2,4,5-benzenetetramine (BTA) ligand in step (1) is replaced by 1,2,5,6-tetrahydroxynaphthalene (NTH2) to obtain the MOFs material CuNTH2.

[0059] Example 7

[0060] The difference from Example 1 is that the 1,2,4,5-benzenetetramine (BTA) ligand in step (1) is replaced by 2,3,6,7-tetraaminoanthracene (ATA1) to obtain the MOFs material CuATA1.

[0061] Example 8

[0062] The difference from Example 1 is that the 1,2,4,5-benzenetetramine (BTA) ligand in step (1) is replaced by 2,3,6,7-tetrahydroxyanthracene (ATH1) to obtain the MOFs material CuATH1.

[0063] Example 9

[0064] The difference from Example 1 is that the 1,2,4,5-benzenetetramine (BTA) ligand in step (1) is replaced by 1,2,5,6-tetraaminoanthracene (ATA2) to obtain the MOFs material CuATA2.

[0065] Example 10

[0066] The difference from Example 1 is that the 1,2,4,5-benzenetetramine (BTA) ligand in step (1) is replaced by 1,2,5,6-tetrahydroxyanthracene (ATH2) to obtain the MOFs material CuATH2.

[0067] Comparative Example 1

[0068] The difference from Example 1 is that the copper acetate monohydrate in step (1) is replaced by cobalt acetate tetrahydrate to obtain the MOFs material CoBTA.

[0069] Comparative Example 2

[0070] The difference from Example 1 is that the copper acetate monohydrate in step (1) is replaced by nickel acetate tetrahydrate to obtain the MOFs material NiBTA.

[0071] Comparative Example 3

[0072] The difference from Example 1 is that in step (1), the molar ratio of 1,2,4,5-benzenetetramine (BTA) ligand and cupric acetate monohydrate is 1:1 to obtain MOFs material CuBTA-2.

[0073] Comparative Example 4

[0074] The difference from Example 1 is that the molar ratio of 1,2,4,5-benzenetetramine (BTA) ligand and cupric acetate monohydrate in step (1) is 1:3 to obtain MOFs material CuBTA-3.

[0075] Comparative Example 5

[0076] The difference from Example 1 is that in step (1), the molar ratio of 1,2,4,5-benzenetetramine (BTA) ligand and cupric acetate monohydrate is 1:4 to obtain MOFs material CuBTA-4.

[0077] Comparative Example 6

[0078] The difference from Example 1 is that N,N-dimethylformamide (DMF) in step (1) is replaced by methanol to obtain the MOFs material CuBTA-5.

[0079] Comparative Example 7

[0080] The difference from Example 1 is that N,N-dimethylformamide (DMF) in step (1) is replaced by ethanol to obtain the MOFs material CuBTA-6.

[0081] Comparative Example 8

[0082] The difference from Example 1 is that N,N-dimethylformamide (DMF) in step (1) is replaced by acetone to obtain the MOFs material CuBTA-7.

[0083] Comparative Example 9

[0084] The difference from Example 1 is that N,N-dimethylformamide (DMF) in step (1) is replaced by chloroform to obtain the MOFs material CuBTA-8.

[0085] Comparative Example 10

[0086] The difference from Example 1 is that in step (3), the temperature is 40° C. to obtain the MOFs material CuBTA-9.

[0087] Comparative Example 11

[0088] The difference from Example 1 is that in step (3), the temperature is 50° C. to obtain the MOFs material CuBTA-10.

[0089] Comparative Example 12

[0090] The difference from Example 1 is that in step (3), the temperature is 60° C. to obtain the MOFs material CuBTA-11.

[0091] Comparative Example 13

[0092] The difference from Example 1 is that the copper acetate monohydrate in step (1) is replaced by copper sulfate pentahydrate to obtain the MOFs material CuBTA-12.

[0093] Comparative Example 14

[0094] The difference from Example 1 is that the copper acetate monohydrate in step (1) is replaced by copper chloride dihydrate to obtain the MOFs material CuBTA-13.

[0095] Embodiment 11

[0096] The MOFs materials prepared in the examples and comparative examples are used to prepare gas sensors:

[0097] Figure 3 Schematic diagram of the gas sensor interdigital electrode and gas sensor preparation. The interdigital electrode used in the preparation of the sensor is manufactured using photolithography and micromachining technology. The size is 690×730μm 2 , with a spacing of 20μm. The manufacturing process includes the continuous deposition of a 20nm Ti layer and a 180nm Au layer on a patterned Si / SiO2 substrate. The prepared MOFs sensitive material is dispersed in ethanol, and about 3μL of the dispersed liquid is dropped onto the interdigital electrode using a pipette, and dried in a vacuum oven at 60℃ for 2h. This step is repeated until a layer of MOFs sensitive material is evenly deposited on the electrode surface.

[0098] Example 12

[0099] The gas sensor prepared in Example 11 was tested for gas sensing performance:

[0100] Figure 4 Schematic diagram of a gas sensing performance test according to one or more embodiments.

[0101] The gas sensor is placed in the test chamber, and the target gas is introduced by dynamic gas distribution at room temperature. A constant working voltage of 500mV is applied between the sensor electrodes, and the resistance change of the sensor in the inert gas and target gas environment is detected by the Agilent 4156C semiconductor parameter analyzer. Before the target gas is introduced, the chamber is purified with dry compressed nitrogen (flowmeter 3) to stabilize the baseline signal, and compressed nitrogen (flowmeter 2) is used as a carrier gas to dilute the target gas, and the target gas is controlled by a mass flow controller (flowmeter 1). The difference in resistance of the sensor in dry nitrogen and in the target gas and the current ratio in dry nitrogen (|Ia-Ig| / Ia×100%) are the response values ​​of the device to the target gas, and the response and recovery time are defined by reaching 90% saturation of the response and recovery curves.

[0102] Figure 5 The X-ray diffraction pattern (XRD) of the gas sensing material of the embodiment of the present invention is shown in the figure. As shown in the figure, the XRD diffraction peak positions of NiBTA and CuBTA are basically consistent with the XRD diffraction peak positions reported in the literature, and diffraction peaks corresponding to (001), (100), and (010) crystal planes can be observed, and the peak shape is relatively sharp, indicating that the crystal structure of the experimental sample is relatively orderly, the atomic arrangement inside the crystal is relatively regular, and the purity is relatively high.

[0103] Figure 6 This is a scanning electron microscope (SEM) image of the gas sensing material CuBTA-1 obtained in Example 1 of the present invention. As shown in the figure, the obtained gas sensing material CuBTA-1 has a granular morphology with a particle size of about 50-100 nm. Nano-scale particles are beneficial to increase the specific surface area of ​​the material, thereby improving the gas sensing performance of the material.

[0104] Figure 7 This is a schematic diagram of the concentration gradient response of the gas sensing material CuBTA-1 obtained in Example 1 of the present invention to CO. The response of the sensor based on the CuBTA-1 gas sensing material prepared in Example 1 to CO concentrations of 10, 20, 50, and 100 ppm was tested at room temperature. In the figure, the horizontal axis is the test time and the vertical axis is the response value. It can be seen from the figure that the response value of the sensor of the CuBTA-1 gas sensing material to 100ppm carbon monoxide reaches 25.2%. The lowest detectable carbon monoxide concentration reaches 10ppm, and the corresponding response value is 1.9%. As the concentration of carbon monoxide increases, the response value of the sensor to the gas also increases, and the response values ​​to 10, 20, 50, and 100ppm carbon monoxide are 1.9%, 4.2%, 7.6%, and 25.2%, respectively.

[0105] Figure 8The figure is a schematic diagram of the cyclic response of the gas sensing material CuBTA-1 obtained in Example 1 of the present invention to 50ppm CO. The cyclic response performance of the sensor based on the CuBTA-1 gas sensing material prepared in Example 1 to 50ppm CO was tested at room temperature. In the figure, the horizontal axis is the test time and the vertical axis is the response value. The response time of the sensor to the gas is about 400s, and the recovery time is also about 400s. After six response-recovery cycles, the response value of the sensor is maintained at more than 7.6%, and the response time remains basically unchanged, indicating that the sensor prepared in the aforementioned embodiment has good cyclic stability.

[0106] Fig. 9 The schematic diagram of the selectivity of the gas sensing material CuBTA-1 obtained in Example 1 of the present invention to 50ppm gas. The response of the sensor based on the CuBTA-1 gas sensing material prepared in Example 1 to 50ppm CO, ammonia, hydrogen sulfide, carbon dioxide, methane, hydrogen, nitrogen dioxide, and ethanol was tested at room temperature. It was found that CuBTA-1 had certain response characteristics to CO, ammonia, and hydrogen sulfide, and could be used as a gas sensor to detect these gases; at the same time, the response values ​​to the other five gases did not exceed 5%, so CuBTA-1 showed good gas selectivity.

[0107] Table 2 Reaction parameters and performance parameters of each embodiment

[0108]

[0109]

[0110]

[0111] Note: L:MII is the molar ratio of ligand L to metal ion MII; the response value is the response value of the metal organic framework material to 50 ppm CO; the recovery time is the recovery time of the metal organic framework material to 50 ppm CO.

[0112] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention can be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the present invention.

Claims

1. A gas sensing material, characterized in that: The gas sensing material is a metal organic framework material with a one-dimensional coordination structure, and the metal organic framework material includes a complex of metal and organic ligand; Among them, the metal includes one of copper, nickel, and cobalt, the organic ligand includes tetrasubstituted benzene and tetrasubstituted condensed aromatic hydrocarbons, the substituents are hydroxyl groups or amine groups, the four substituents are grouped in two, each group is arranged in ortho positions, and the two groups are arranged in a central symmetric manner.

2. The gas sensing material according to claim 1, characterized in that: The organic ligands include 1,2,4,5-tetrasubstituted benzene, 2,3,6,7-tetrasubstituted naphthalene, 1,2,5,6-tetrasubstituted naphthalene, 2,3,6,7-tetrasubstituted anthracene, and 1,2,5,6-tetrasubstituted anthracene, wherein R is a hydroxyl group or an amino group.

3. The gas sensing material according to claim 1 or 2, characterized in that: The response gas of the gas sensing material includes one or more of carbon monoxide, ammonia, and hydrogen sulfide.

4. A method for preparing a gas sensing material, characterized in that: The method comprises the steps of dripping a metal ion solution into an organic ligand solution, uniformly mixing the mixture, and stirring the mixture for reaction to obtain the gas sensing material.

5. The preparation method according to claim 4, characterized in that: The stirring reaction time is 24 hours, and the temperature is 25-60°C.

6. The preparation method according to claim 4, characterized in that: The organic ligand solution includes tetrasubstituted benzene and tetrasubstituted condensed aromatic hydrocarbon solutions, and the metal ion solution includes divalent copper ion solution, divalent nickel ion solution and divalent cobalt ion solution.

7. The preparation method according to claim 6, characterized in that: The molar ratio of the organic ligand to the metal ion is 1:1-4.

8. The preparation method according to claim 7, characterized in that: The metal ion solution includes a divalent metal salt solution, and the divalent metal salt includes hydrated acetate, hydrated sulfate, and hydrated chloride.

9. The preparation method according to claim 7, characterized in that: The solvent of the organic ligand solution includes one or more of methanol, ethanol, acetone, N,N-dimethylformamide and chloroform.

10. Use of the gas sensing material according to claims 1 to 3 in a sensor.

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