Two-dimensional Cu-TCPP modified bimetallic MOF composite material, preparation method and application thereof, gas sensitive sensor and preparation method and application thereof

Abstract

The invention relates to the field of gas sensing, and discloses a two-dimensional Cu-TCPP modified bimetallic MOF composite material and a preparation method and application thereof, a gas sensor and a preparation method and application thereof, the two-dimensional Cu-TCPP modified bimetallic MOF composite material comprises a Zn / Co-MOF material, and the surface of the Zn / Co-MOF material is modified with a Cu-TCPP nanosheet. According to the two-dimensional Cu-TCPP modified bimetallic MOF composite material, the characteristics of large surface area and high electron transmission efficiency of a two-dimensional material and the characteristics of porosity, high specific surface area, chemical tunability and the like of an MOF material are fused, and the catalytic activity of the material is enhanced through introduction of Cu-TCPP, so that the detection sensitivity of target gas is improved; resistance change detection of gas molecules is realized, and the gas molecules are converted into electric signals to be output and used for monitoring characteristic gas of dissolved gas in transformer oil.

Description

Technical Field

[0001] The present invention relates to the field of gas sensing, and specifically to a two-dimensional Cu-TCPP modified bimetallic MOF composite material and its preparation method and application, a gas sensor and its preparation method and application. Background Art

[0002] As a key component of the power grid, it is difficult to directly detect potential internal defects of power transformers through external monitoring means. However, these defects often cause chemical changes in transformer oil and insulating materials, and then generate and dissolve various fault characteristic gases such as hydrogen, methane, and ethylene. Therefore, the detection of dissolved gases in transformer oil has become an important means to ensure the safe and stable operation of the power grid, which can effectively reveal most of the potential problems and defects inside the transformer.

[0003] In the field of detection technology for dissolved gases in transformer oil, although traditional methods such as gas chromatography have certain application values, they have obvious limitations in terms of real-time performance, operation convenience, and cost-effectiveness. In view of this, metal oxide semiconductor (MOS) nanomaterials have shown great potential in the detection field of toxic, harmful, and flammable gases due to their high sensitivity, low cost, miniaturized design, and good compatibility with modern electronic systems. However, when applied to the detection of low-concentration gases (such as H 2 ), single MOS materials face challenges such as insufficient sensitivity, poor selectivity, and the need for a relatively high operating temperature, which seriously hinder their practical applications in the detection of dissolved gases in transformer oil. Summary of the Invention

[0004] The purpose of the present invention is to overcome the problems that when metal oxide semiconductor nanomaterials are applied to the detection of low-concentration gases (such as H 2 ), single MOS materials face problems such as insufficient sensitivity, poor selectivity, and the need for a relatively high operating temperature, and to provide a two-dimensional Cu-TCPP modified bimetallic MOF composite material and its preparation method and application, a gas sensor and its preparation method and application. The two-dimensional Cu-TCPP modified bimetallic MOF composite material ingeniously adopts an improved hydrothermal synthesis technique. First, a bimetallic Zn / Co-MOF is carefully constructed as the core framework material, which itself has excellent gas adsorption and transmission characteristics. Subsequently, through a precisely controlled in-situ growth strategy, a thin layer of two-dimensional Cu-TCPP nanosheets is uniformly covered on the surface of Zn / Co-MOF. This surface modification layer not only greatly enriches the specific surface area and active sites of the material, but also effectively promotes the interaction between H 2 gas molecules and the sensing interface, thereby significantly enhancing the sensitivity of the sensor to dissolved gases in transformer oil, especially H 2Gas-sensing response. This composite material exhibits unprecedented high sensitivity and can achieve precise detection even in a low-concentration gas environment, providing strong technical support for the early warning and diagnosis of internal faults in transformers.

[0005] To achieve the above object, on the one hand, the present invention provides a two-dimensional Cu-TCPP modified bimetallic MOF composite material. The two-dimensional Cu-TCPP modified bimetallic MOF composite material includes a Zn / Co-MOF material, and the surface of the Zn / Co-MOF material is modified with Cu-TCPP (copper tetracarboxyphenyl porphyrin) nanosheets; this two-dimensional Cu-TCPP modified bimetallic MOF composite material is a nanoporous composite material.

[0006] On the second aspect, the present invention provides a preparation method of the above two-dimensional Cu-TCPP modified bimetallic MOF composite material, including the following steps:

[0007] Mix a zinc salt, a cobalt salt, and surfactant A with a solvent, and stir to obtain solution A;

[0008] Mix isophthalic acid with DMF, and stir to obtain solution B;

[0009] Mix solution A with solution B, then carry out a hydrothermal reaction. After the hydrothermal reaction is completed, cool to obtain material A. Perform solid-liquid separation on material A to obtain solid product A. Wash and dry solid product A to obtain the Zn / Co-MOF material;

[0010] Mix the Zn / Co-MOF material with a mixed solvent of DMF and ethanol, and ultrasonically obtain a Zn / Co-MOF dispersion. Mix a copper salt, surfactant B, and meso-tetrakis(4-carboxyphenyl)porphine with the Zn / Co-MOF dispersion to obtain a mixed material;

[0011] React the mixed material. After the reaction is completed, cool to obtain material B. Perform solid-liquid separation on material B to obtain solid product B. Wash and dry solid product B to obtain the two-dimensional Cu-TCPP modified bimetallic MOF composite material.

[0012] Further, mix a zinc salt, a cobalt salt, and surfactant A with a solvent, wherein the weight ratio of the zinc salt, the cobalt salt, and surfactant A is 1:1:15-20. Controlling the ratio of each substance within this range helps to form a stable and structurally uniform Zn / Co-MOF material subsequently.

[0013] Preferably, the ratio of the total weight of the zinc salt, the cobalt salt and the surfactant A to the volume of the solvent is 1 g: 15-30 mL. Controlling the amount of the solvent within this range can control the concentration of the reaction system, which is beneficial to the growth and dispersion of MOF crystals.

[0014] Furthermore, the zinc salt is selected from one or more of zinc nitrate, zinc chloride, zinc sulfate and zinc carbonate; in a specific embodiment, the zinc salt is selected from zinc nitrate.

[0015] Preferably, the cobalt salt is selected from one or more of cobalt nitrate, cobalt chloride, cobalt acetate and cobalt sulfate; in a specific embodiment, the cobalt salt is selected from cobalt nitrate.

[0016] The surfactant A used in the present invention is to enhance the dispersibility and stability of the material, and the surfactant A is selected from one or more of polyvinyl pyrrolidone (PVP), polyethylene glycol, sodium lauryl sulfate and polysorbate; in a specific embodiment, the surfactant A is polyvinyl pyrrolidone.

[0017] In a preferred embodiment, the solvent contains water and anhydrous alcohol, and the volume ratio of water to anhydrous alcohol is 1:1-2.

[0018] In the present invention, the anhydrous alcohol is anhydrous methanol and / or anhydrous ethanol; in a specific case, the anhydrous alcohol is anhydrous ethanol.

[0019] In the present invention, zinc salt, cobalt salt and surfactant A are mixed with a solvent. In order to further ensure that all solutes can be fully dissolved and mixed evenly, it is necessary to stir for a certain time at an appropriate stirring speed. Therefore, it is preferred to stir at a stirring speed of 300 to 500 rpm for 15 to 30 minutes to obtain a uniform and transparent solution A.

[0020] In the present invention, isophthalic acid is mixed with DMF (N, N-dimethylformamide). In order to ensure that the solute can be fully dissolved and mixed evenly, stirring is also required under appropriate conditions, preferably stirring at a stirring speed of 300 to 800 rpm for 15 to 20 minutes to obtain a clear solution B (through sufficient stirring, ensure that the isophthalic acid is completely dissolved in DMF); wherein, phthalic acid, as an organic ligand, plays a key role in the construction of MOF materials, so the amount of phthalic acid needs to be reasonably controlled. In a preferred case, the solid-liquid ratio of isophthalic acid to DMF is 0.1 g: 20 to 30 mL.

[0021] Further, to avoid precipitation caused by excessive local concentration when Solution A and Solution B are mixed, in the preferred case, Solution B is slowly and continuously poured into Solution A while gently stirring to obtain a uniformly mixed liquid, and then the mixed liquid is subjected to a hydrothermal reaction.

[0022] Preferably, the volume ratio of Solution A to Solution B is 1:1 - 2.

[0023] Among them, the conditions of the hydrothermal reaction include: the temperature is 120 - 180 °C, the time is 12 - 18 h. Controlling the dosages of Solution A and Solution B and the conditions of the hydrothermal reaction within the above ranges helps to form a stable and uniformly structured Zn / Co-MOF material.

[0024] In the present invention, after the hydrothermal reaction, it is preferably naturally cooled to room temperature to avoid damage to the material structure caused by a sudden drop in temperature.

[0025] In the present invention, the room temperature refers to 20 - 30 °C.

[0026] In the present invention, when performing solid-liquid separation on Material A, the operation of the solid-liquid separation can be filtration or centrifugation, and further preferably filtration.

[0027] Further, in order to remove unreacted raw materials, solvent residues, and possibly generated impurities, the specific operations of washing and drying the solid product A include: centrifugally washing the solid product A three times with anhydrous ethanol (the rotation speed for each centrifugal washing of the solid product A is 10000 - 12000 revolutions per minute, the time is 10 - 20 min, and after each centrifugal washing, the precipitated part after centrifugation is retained and the supernatant is discarded), and then drying the centrifugally washed solid product A to ensure that the solvent in the centrifugally washed solid product A is completely volatilized to obtain a pure Zn / Co-MOF material, where the conditions of the drying include: the temperature is 60 - 80 °C, the time is 12 - 24 h.

[0028] Further, in the mixed solvent of DMF and ethanol, the volume ratio of DMF to ethanol is 2 - 4:1.

[0029] In the present invention, the Zn / Co-MOF material is mixed with the mixed solvent of DMF and ethanol, where the solid-liquid ratio of the Zn / Co-MOF material to the mixed solvent of DMF and ethanol is 0.1 - 0.2 g:120 mL.

[0030] Further, the conditions of the ultrasonic treatment include: the time is 20 - 60 min, the power is 200 - 500 W; controlling the ultrasonic conditions within the above ranges helps to completely disperse the Zn / Co-MOF material.

[0031] Further preferably, the specific operation of mixing copper salt, surfactant B and meso-tetrakis(4-carboxyphenyl)porphine with the Zn / Co-MOF dispersion to obtain a mixed material includes: mixing the copper salt and surfactant B with the Zn / Co-MOF dispersion, stirring for 15 - 30 min to obtain a copper-containing dispersion, and then mixing meso-tetrakis(4-carboxyphenyl)porphine with the copper-containing dispersion, and stirring for 5 - 15 min at a stirring speed of 300 - 800 revolutions per minute to obtain a mixed material.

[0032] The method of adding materials in batches in the above operation is to facilitate the full mixing of materials and enable them to grow evenly on the surface of the Zn / Co-MOF material.

[0033] Among them, the weight ratio of copper salt, surfactant B and meso-tetrakis(4-carboxyphenyl)porphine is 1:3 - 5:1.

[0034] Further, the weight ratio of the Zn / Co-MOF material, copper salt, surfactant B and meso-tetrakis(4-carboxyphenyl)porphine is 4 - 6:1:3 - 5:1. Controlling the dosage of each substance within this range is beneficial for the uniform growth of Cu-TCPP nanosheets on the surface of the Zn / Co-MOF material.

[0035] In the preferred case, the copper salt is selected from one or more of copper nitrate, copper chloride and copper sulfate; in a specific embodiment, the copper salt is selected from copper nitrate.

[0036] Further, the surfactant B is selected from one or more of polyvinylpyrrolidone, polyethylene glycol, sodium dodecyl sulfate and polysorbate; in a specific embodiment, the surfactant B is polyvinylpyrrolidone.

[0037] In the present invention, the reaction conditions include: the temperature is 80 - 120 °C and the time is 3 - 6 h. Reacting under these conditions is beneficial for the uniform growth of Cu-TCPP nanosheets on the surface of the Zn / Co-MOF material.

[0038] In the preferred case, after the reaction is completed, it is also preferably cooled naturally to room temperature to avoid damage to the material structure caused by a sudden drop in temperature.

[0039] In the present invention, when performing solid-liquid separation on the material B, the operation of solid-liquid separation can be filtration or centrifugation, and further preferably filtration.

[0040] Further, in order to remove unreacted raw materials, solvent residues, and possible impurities generated, the specific operations of washing and drying the solid product B include: centrifugally washing the solid product B three times with absolute ethanol (the rotation speed for each centrifugal washing of the solid product B is 10,000 - 12,000 revolutions per minute, and the time is 10 - 20 min. After each centrifugal washing, the precipitated part after centrifugation is retained, and the supernatant is discarded), and then drying the centrifugally washed solid product B to obtain a two-dimensional Cu-TCPP modified bimetallic MOF composite material, where the drying conditions include: the temperature is 60 - 80 °C, and the time is 12 - 24 h.

[0041] The two-dimensional Cu-TCPP modified bimetallic MOF composite material prepared by the present invention has high sensitivity to dissolved gases in transformer oil such as hydrogen, mainly due to its unique structure and composition. The bimetallic Zn / Co-MOF material serves as the core framework material, and through a precisely controlled in-situ growth strategy, a ultrathin layer of two-dimensional Cu-TCPP nanosheets is uniformly covered on the surface of the Zn / Co-MOF material. This composite material combines the characteristics of two-dimensional Cu-TCPP nanosheets and the advantages of bimetallic MOF materials, forming abundant nanochannels and active sites. These nanochannels are conducive to the diffusion and transmission of gases, enabling the composite material to efficiently capture and identify dissolved gases in transformer oil, such as hydrogen. At the same time, the Cu-TCPP nanosheets, as peroxidase mimics, have specific catalytic activity, which can promote chemical reactions with these gases, thereby further improving the sensitivity. In addition, the tunability and high specific surface area of the bimetallic MOF material also provide favorable conditions for gas adsorption and detection. Specifically, when the dissolved hydrogen gas molecules in transformer oil come into contact with the surface of the two-dimensional Cu-TCPP modified bimetallic MOF composite material, they will interact with the active sites on the material surface, resulting in a change in the resistance of the material. This resistance change can be captured by the gas sensor and converted into a corresponding electrical signal output, thereby realizing the detection and measurement of dissolved gases in transformer oil such as hydrogen and methane.

[0042] The third aspect of the present invention provides an application of the above two-dimensional Cu-TCPP modified bimetallic MOF composite material in a gas sensor.

[0043] The fourth aspect of the present invention provides a gas sensor, and the surface of the ceramic tube electrode of the gas sensor is coated with the above two-dimensional Cu-TCPP modified bimetallic MOF composite material.

[0044] The fifth aspect of the present invention provides a preparation method of the above gas sensor, including the following steps:

[0045] Mix terpineol and a polymer binder to obtain a mixed binder. After grinding the two-dimensional Cu-TCPP modified bimetallic MOF composite material, mix it with the mixed binder to obtain a gas-sensitive paste.

[0046] Clean the ceramic tube electrode, then dry it. Then apply the gas-sensitive paste on the surface of the dried ceramic tube electrode to obtain a ceramic tube electrode coated with the gas-sensitive paste. Dry the ceramic tube electrode coated with the gas-sensitive paste, then insert a nickel-chromium heating wire into the dried ceramic tube electrode. Then weld the platinum wire and the nickel-chromium heating wire on the dried ceramic tube electrode to a six-pin socket, and then perform aging to obtain a gas-sensitive sensor.

[0047] Preferably, the polymer binder is selected from one or more of ethyl cellulose, polyurethane, and polystyrene.

[0048] In a preferred embodiment, the weight ratio of terpineol to the polymer binder is 95-99:1. This ratio ensures that the binder system has good volatility and coating properties. Among them, terpineol, as the main component, provides appropriate volatility and solubility; while the polymer binder, as a small additive, mainly plays the role of enhancing the adhesion force and improving the mechanical strength of the film.

[0049] Preferably, the grinding time is 10-15 min.

[0050] Furthermore, the weight ratio of the two-dimensional Cu-TCPP modified bimetallic MOF composite material to the mixed binder is 1:20-50.

[0051] In the present invention, preferably, ultrasonic cleaning with absolute ethanol is used to clean the ceramic tube electrode to remove surface impurities.

[0052] In a preferred embodiment, the drying conditions include: temperature 60-80 °C, time 12-24 h.

[0053] Among them, the dosage of the applied gas-sensitive paste only needs to ensure that the thickness of the two-dimensional Cu-TCPP modified bimetallic MOF composite material coated on the surface of the ceramic tube electrode in the finished gas-sensitive sensor is 100-300 nm.

[0054] Preferably, the drying conditions include: temperature 60-80 °C, time 12-24 h.

[0055] Furthermore, weld the four platinum wires on the dried ceramic tube electrode to four pins of the six-pin socket, then weld the nickel-chromium heating wire to the other two pins of the six-pin socket, and finally perform aging on the aging platform to ensure the stability of the circuit during the test.

[0056] In a specific embodiment, the aging conditions include: a voltage of 5V and a time of 7 days.

[0057] The sixth aspect of the present invention provides an application of the above gas sensor in hydrogen detection.

[0058] By combining the advantages of two-dimensional Cu-TCPP nanosheets and bimetallic Zn / Co-MOF materials, the present invention creates a brand-new composite material. This design not only integrates the characteristics of large surface area, high electron transport efficiency of two-dimensional materials and the porosity, high specific surface area and chemical tunability of MOF materials, but also enhances the catalytic activity of the material through the introduction of Cu-TCPP, thereby improving the detection sensitivity to target gases, realizing the detection of resistance changes of gas molecules, converting them into electrical signal outputs, and being used for monitoring the characteristic gases of dissolved gases in transformer oil.

[0059] In the preparation process, a two-step hydrothermal synthesis method is adopted. First, the bimetallic Zn / Co-MOF material is prepared, and then Cu-TCPP nanosheets are introduced through secondary hydrothermal synthesis on this basis. This step-by-step synthesis strategy ensures the structural integrity and performance optimization of the composite material, while avoiding complex multi-step chemical reactions and simplifying the preparation process.

[0060] In the preparation process of the gas sensor, a method of mixing the composite material with a specific binder and grinding it into a slurry, and uniformly coating it on a ceramic tube is adopted. This method not only improves the stability and reliability of the sensor, but also enables the sensor to have better sensitivity and response speed.

[0061] Compared with the prior art, the present invention has the following beneficial effects:

[0062] Improve sensitivity: Due to the catalytic activity of two-dimensional Cu-TCPP nanosheets and the porous structure and high specific surface area of the bimetallic MOF material, the composite material shows extremely high sensitivity to dissolved gases in transformer oil such as hydrogen. This enables the sensor to detect and analyze target gases more accurately, improving the accuracy and reliability of detection.

[0063] Enhance stability: By optimizing the preparation process and sensor preparation technology, the sensor prepared by this invention has better stability and durability. This has important significance in practical applications, can extend the service life of the sensor, and reduce the maintenance cost.

[0064] Broadening the application scope: Due to the extremely high specific surface area and porosity of MOF materials, they have excellent adsorption and separation capabilities for gas molecules. In addition, the structure and function of MOF materials can be precisely regulated through chemical synthesis, thereby achieving highly selective detection of specific gases. These characteristics give MOF materials significant advantages in the low-concentration detection of dissolved gases in transformer oil, and can solve the deficiencies of single MOS materials in terms of sensitivity, selectivity, stability, and operating temperature. Therefore, combining the characteristics of MOF materials to develop new technologies for detecting dissolved gases in transformer oil is of great significance for improving the safety and stability of the power grid. Moreover, the gas sensor prepared by this invention is not only applicable to the detection of dissolved gases in transformer oil, but can also be widely used in gas detection and analysis in other fields. Its high sensitivity and stability make this sensor have broad application prospects in fields such as environmental monitoring, industrial safety, and medical health. Description of the Drawings

[0065] Figure 1 is a schematic diagram of the preparation of the two-dimensional Cu-TCPP modified bimetallic MOF composite material of the present invention;

[0066] Figure 2 is the SEM image of the two-dimensional Cu-TCPP modified bimetallic MOF composite material obtained in Example 1;

[0067] Figure 3 is the XRD pattern of the two-dimensional Cu-TCPP modified bimetallic MOF composite material obtained in Example 1;

[0068] Figure 4 is the N 2 adsorption-desorption curve of the two-dimensional Cu-TCPP modified bimetallic MOF composite material obtained in Example 1;

[0069] Figure 5 is the response curve of the gas sensor obtained in Example 1 to 2 ppm H 2 at different operating temperatures. Detailed Description of the Invention

[0070] The following detailed description of the specific embodiments of the present invention is provided in conjunction with the drawings and examples. It should be understood that the specific embodiments described herein are only for the purpose of illustrating and explaining the present invention, and are not used to limit the present invention.

[0071] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0072] In addition, the technical solutions between the various embodiments provided by the present invention can be combined with each other, but it must be based on the fact that ordinary technicians in the field can implement it. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0073] The schematic diagram of the preparation of the two-dimensional Cu-TCPP modified bimetallic MOF composite material of the present invention is as follows Figure 1 shown.

[0074] The room temperature in the following examples all refers to 25°C.

[0075] Example 1

[0076] (1) Mix 30 mL of deionized water and 30 mL of anhydrous ethanol in a beaker to obtain a solvent. Weigh 0.175 g of zinc salt (Zn(NO 3 ) 2 6H 2 O), 0.175 g cobalt salt (Co(NO 3 ) 2 6H 2 O) and 2.625g of surfactant A (PVP) are added one by one into a beaker filled with a solvent, and the zinc salt, cobalt salt and surfactant A are mixed with the solvent, wherein the weight ratio of the zinc salt, the cobalt salt and the surfactant A is 1:1:15, and the ratio of the total weight of the zinc salt, the cobalt salt and the surfactant A to the volume of the solvent is 1g:20mL; stirring is continued at a stirring speed of 300 rpm for 30 minutes to obtain a uniform and transparent solution A;

[0077] (2) 0.1 g of isophthalic acid was mixed with 20 mL of DMF and stirred at 300 rpm for 15 min to obtain a clear solution B;

[0078] (3) Slowly and continuously pour Solution B into Solution A while gently stirring to obtain a uniformly mixed liquid (the volume ratio of Solution A to Solution B is 1:1). Then transfer the mixed liquid to a 100 mL polytetrafluoroethylene-lined reaction kettle, seal it, and place it in an oven preheated to 150 °C for hydrothermal reaction. The conditions of the hydrothermal reaction include: temperature of 150 °C, time of 18 h, and keep the oven temperature constant during this period. After the hydrothermal reaction, let the reaction kettle cool naturally to room temperature to obtain Material A. Filter Material A to obtain Solid Product A, and centrifuge and wash Solid Product A three times with absolute ethanol (the rotation speed for each centrifugal washing of Solid Product A is 11,000 revolutions per minute, and the time is 10 min). Then place the centrifugally washed Solid Product A in a vacuum drying oven for drying. The drying conditions include: temperature of 60 °C, time of 24 h, to obtain the Zn / Co-MOF material;

[0079] (4) Use a measuring cylinder to accurately measure 90 mL of DMF and 30 mL of ethanol and mix them evenly to obtain a mixed solvent of DMF and ethanol. Add 0.12 g of the Zn / Co-MOF material obtained in step (3) to the mixed solvent of DMF and ethanol. The solid-liquid ratio of the Zn / Co-MOF material to the mixed solvent of DMF and ethanol is 0.12 g:120 mL. After mixing, ultrasonicate (the ultrasonication time is 20 min, and the ultrasonication power is 300 W) to obtain a Zn / Co-MOF dispersion. Weigh 30 mg of copper salt (Cu(NO 3 ) 2 ·3H 2 O) and 90 mg of surfactant B (PVP) and add them to the Zn / Co-MOF dispersion. Stir for 15 min to completely dissolve it to obtain a copper-containing dispersion. Then continue to add 30 mg of meso-tetrakis(4-carboxyphenyl)porphine and stir at a stirring speed of 500 revolutions per minute for 15 min to completely dissolve it to obtain a uniformly mixed material; the weight ratio of the copper salt, surfactant B, and meso-tetrakis(4-carboxyphenyl)porphine is 1:3:1; the weight ratio of the Zn / Co-MOF material, copper salt, surfactant B, and meso-tetrakis(4-carboxyphenyl)porphine is 4:1:3:1;

[0080] (5) Transfer the mixed materials obtained in step (4) into a hydrothermal reactor with a polytetrafluoroethylene substrate and seal it. Subsequently, place the hydrothermal reactor in an oven preheated to 80 °C for reaction. The reaction conditions include: temperature of 80 °C and time of 3 h. During the reaction, keep the oven temperature stable to ensure the uniform growth of nanosheets. After the reaction, let the hydrothermal reactor cool naturally to room temperature to obtain material B. Filter material B to obtain solid product B. Wash the solid product B by centrifugation with absolute ethanol three times (the rotation speed for each centrifugal washing of the solid product B is 11,000 revolutions per minute and the time is 10 min). Then dry the centrifugally washed solid product B. The drying conditions include: temperature of 60 °C and time of 24 h to obtain a two-dimensional Cu-TCPP modified bimetallic MOF composite material (Cu-TCPP@Zn / Co-MOF composite material).

[0081] Example 2

[0082] Implemented according to the method of Example 1, except that in step (1), 0.175 g of zinc salt (Zn(NO 3 ) 2 ·6H 2 O), 0.175 g of cobalt salt (Co(NO 3 ) 2 ·6H 2 O) and 3.15 g of surfactant A (PVP) were added one by one to a beaker containing a solvent, that is, the weight ratio of zinc salt, cobalt salt and surfactant A is 1:1:18, to obtain a two-dimensional Cu-TCPP modified bimetallic MOF composite material (Cu-TCPP@Zn / Co-MOF composite material).

[0083] Example 3

[0084] Implemented according to the method of Example 1, except that in step (1), 0.175 g of zinc salt (Zn(NO 3 ) 2 ·6H 2 O), 0.175 g of cobalt salt (Co(NO 3 ) 2 ·6H 2 O) and 3.5 g of surfactant A (PVP) were added one by one to a beaker containing a solvent, that is, the weight ratio of zinc salt, cobalt salt and surfactant A is 1:1:20, to obtain a two-dimensional Cu-TCPP modified bimetallic MOF composite material (Cu-TCPP@Zn / Co-MOF composite material).

[0085] Example 4

[0086] Implemented according to the method of Example 1, except that in step (4), 30 mg of copper salt (Cu(NO 3 ) 2 ·3H 2 O) and 120 mg of surfactant B (PVP) were added to the Zn / Co-MOF dispersion, that is, the weight ratio of copper salt, surfactant B and meso-tetrakis(4-carboxyphenyl)porphine was 1:4:1, and the weight ratio of Zn / Co-MOF material, copper salt, surfactant B and meso-tetrakis(4-carboxyphenyl)porphine was 4:1:4:1; a two-dimensional Cu-TCPP modified bimetallic MOF composite material (Cu-TCPP@Zn / Co-MOF composite material) was obtained.

[0087] Example 5

[0088] A two-dimensional Cu-TCPP modified bimetallic MOF composite material, which includes a Zn / Co-MOF material, and Cu-TCPP nanosheets are modified on the surface of the Zn / Co-MOF material; the two-dimensional Cu-TCPP modified bimetallic MOF composite material is prepared by the method of Example 1.

[0089] Example 6

[0090] A two-dimensional Cu-TCPP modified bimetallic MOF composite material, which includes a Zn / Co-MOF material, and Cu-TCPP nanosheets are modified on the surface of the Zn / Co-MOF material; the two-dimensional Cu-TCPP modified bimetallic MOF composite material is prepared by the method of Example 2.

[0091] Example 7

[0092] A two-dimensional Cu-TCPP modified bimetallic MOF composite material, which includes a Zn / Co-MOF material, and Cu-TCPP nanosheets are modified on the surface of the Zn / Co-MOF material; the two-dimensional Cu-TCPP modified bimetallic MOF composite material is prepared by the method of Example 3.

[0093] Example 8

[0094] A two-dimensional Cu-TCPP modified bimetallic MOF composite material, which includes a Zn / Co-MOF material, and Cu-TCPP nanosheets are modified on the surface of the Zn / Co-MOF material; the two-dimensional Cu-TCPP modified bimetallic MOF composite material is prepared by the method of Example 4.

[0095] Example 9

[0096] The two-dimensional Cu-TCPP modified bimetallic MOF composites in Examples 5-8 all have a porous structure, good catalytic activity and a high specific surface area. This composite material shows extremely high sensitivity to transformer oil dissolved gases such as hydrogen and can be applied to gas sensors, further improving the sensitivity of gas sensors.

[0097] Example 10

[0098] A gas sensor, the surface of the ceramic tube electrode of the gas sensor is coated with the two-dimensional Cu-TCPP modified bimetallic MOF composite material of Example 5.

[0099] Example 11

[0100] A gas sensor, the surface of the ceramic tube electrode of the gas sensor is coated with the two-dimensional Cu-TCPP modified bimetallic MOF composite material of Example 6.

[0101] Example 12

[0102] A gas sensor, the surface of the ceramic tube electrode of the gas sensor is coated with the two-dimensional Cu-TCPP modified bimetallic MOF composite material of Example 7.

[0103] Example 13

[0104] A gas sensor, the surface of the ceramic tube electrode of the gas sensor is coated with the two-dimensional Cu-TCPP modified bimetallic MOF composite material of Example 8.

[0105] Example 14

[0106] The preparation method of the gas sensor of Example 10 specifically includes the following steps:

[0107] S1. Mix terpineol and a polymer binder (ethyl cellulose) evenly at a weight ratio of 99:1 to obtain a mixed binder. After grinding the two-dimensional Cu-TCPP modified bimetallic MOF composite material of Example 5 in an agate mortar for 10 minutes, it is evenly mixed with the mixed binder to form a gas-sensitive paste with a uniform concentration; the weight ratio of the two-dimensional Cu-TCPP modified bimetallic MOF composite material to the binder is 1:20;

[0108] S2. Ultrasonically clean the ceramic tube electrode with absolute ethanol to remove surface impurities. Then, place it in a drying oven at 60 °C for 24 h. Next, evenly apply the gas-sensitive slurry obtained in step S1 onto the surface of the dried ceramic tube electrode to obtain a ceramic tube electrode coated with the gas-sensitive slurry. Dry the ceramic tube electrode coated with the gas-sensitive slurry at 60 °C for 24 h. Insert a nickel-chromium heating wire into the dried ceramic tube electrode. Then, solder the four platinum wires on the dried ceramic tube electrode to four pins of a six-pin socket with a soldering iron. Next, solder the nickel-chromium heating wire to the other two pins of the six-pin socket with a soldering iron. Finally, perform aging on an aging platform. The aging conditions include: voltage of 5 V and time of 7 days to obtain a gas-sensitive sensor. The thickness of the two-dimensional Cu-TCPP modified bimetallic MOF composite material coated on the surface of the ceramic tube electrode in this gas-sensitive sensor is 100 nm.

[0109] Example 15

[0110] A method for preparing the gas-sensitive sensor of Example 11, and its specific preparation method is implemented according to the method of Example 14. The difference is that in step S1, the N-Zn / Co-NO gas-sensitive material of Example 6 is used to prepare the gas-sensitive sensor.

[0111] Example 16

[0112] A method for preparing the gas-sensitive sensor of Example 12, and its specific preparation method is implemented according to the method of Example 14. The difference is that in step S1, the N-Zn / Co-NO gas-sensitive material of Example 7 is used to prepare the gas-sensitive sensor.

[0113] Example 17

[0114] A method for preparing the gas-sensitive sensor of Example 13, and its specific preparation method is implemented according to the method of Example 14. The difference is that in step S1, the N-Zn / Co-NO gas-sensitive material of Example 8 is used to prepare the gas-sensitive sensor.

[0115] Example 18

[0116] The gas-sensitive sensors in Examples 10 to 13 all have good sensitivity and can all be used to detect hydrogen.

[0117] Comparative Example 1

[0118] Implemented according to the method of Example 1. The difference is that in step (1), no cobalt salt is used to obtain a Zn-MOF material, and in step (4), the Zn-MOF material is used to replace the Zn / Co-MOF material to obtain a gas-sensitive material D1.

[0119] Comparative Example 2

[0120] It was implemented according to the method of Example 14. The difference is that in step S1, the gas-sensitive material D1 was used to replace the two-dimensional Cu-TCPP modified bimetallic MOF composite material of Example 5 to obtain a gas sensor.

[0121] Comparative Example 3

[0122] It was implemented according to the method of Example 1. The difference is that in step (1), zinc salt was not used to obtain a Co-MOF material, and in step (4), the Co-MOF material was used to replace the Zn / Co-MOF material to obtain a gas-sensitive material D2.

[0123] Comparative Example 4

[0124] It was implemented according to the method of Example 14. The difference is that in step S1, the gas-sensitive material D2 was used to replace the two-dimensional Cu-TCPP modified bimetallic MOF composite material of Example 5 to obtain a gas sensor.

[0125] Comparative Example 5

[0126] It was implemented according to the method of Example 1. The difference is that the Zn / Co-MOF material was not prepared, and the Cu-TCPP nanosheets were directly prepared. The specific preparation method is as follows: 90 mL of DMF and 30 mL of ethanol were accurately measured using a graduated cylinder and mixed evenly to obtain a mixed solvent of DMF and ethanol. 30 mg of copper salt (Cu(NO 3 ) 2 ·3H 2 O) and 90 mg of surfactant B (PVP) were added to the mixed solvent of DMF and ethanol, and after stirring for 15 min, it was completely dissolved to obtain a copper-containing dispersion. Then, 30 mg of meso-tetrakis(4-carboxyphenyl)porphine was added, and after stirring at a stirring speed of 500 revolutions per minute for 15 min, it was completely dissolved to obtain a uniformly mixed mixture; the weight ratio of the copper salt, surfactant B, and meso-tetrakis(4-carboxyphenyl)porphine was 1:3:1; the obtained mixture was transferred to a hydrothermal reactor with a polytetrafluoroethylene liner and sealed. Subsequently, the hydrothermal reactor was placed in an oven preheated to 80 °C for reaction. The reaction conditions included: temperature of 80 °C, time of 3 h. During the reaction, the oven temperature was kept stable to ensure uniform growth of the nanosheets. After the reaction, the hydrothermal reactor was allowed to cool naturally to room temperature to obtain a reaction product. The reaction product was filtered to obtain a solid product. The solid product was centrifugally washed three times with absolute ethanol (the rotation speed for each centrifugal washing of the solid product was 11,000 revolutions per minute, and the time was 10 min). Then, the centrifugally washed solid product was dried. The drying conditions included: temperature of 60 °C, time of 24 h to obtain two-dimensional Cu-TCPP nanosheets.

[0127] Comparative Example 6

[0128] The method of Example 14 was implemented, except that in step S1, the two-dimensional Cu-TCPP nanosheets of Comparative Example 5 with equal weight were used to replace the two-dimensional Cu-TCPP modified bimetallic MOF composite material of Example 5 to obtain a gas sensor.

[0129] Test Example 1

[0130] The two-dimensional Cu-TCPP modified bimetallic MOF composite material obtained in step (5) of Example 1 was subjected to SEM detection, and the SEM image is as Figure 2 shown. It can be seen from Figure 2 that the prepared two-dimensional Cu-TCPP modified bimetallic MOF composite material is a flower cluster-like structure, and the surface of the particles is decorated with two-dimensional Cu-TCPP nanosheets. The design of this structure forms a large number of nano-scale channels and active sites inside the composite material, which not only promotes the rapid diffusion and effective adsorption of hydrogen, but also greatly increases the contact area between the material and hydrogen molecules. In addition, as a peroxidase mimic, Cu-TCPP nanosheets have specific catalytic activity, which can accelerate the chemical reaction with hydrogen molecules, thereby further improving the detection sensitivity, enabling the two-dimensional Cu-TCPP modified bimetallic MOF composite material to accurately and rapidly respond to hydrogen at low concentrations, providing an efficient and reliable solution for hydrogen monitoring.

[0131] Test Example 2

[0132] The two-dimensional Cu-TCPP modified bimetallic MOF composite material obtained in step (5) of Example 1 was subjected to XRD detection, and the XRD image is as Figure 3 shown. Figure 3 It can be seen from

[0133] that there are multiple obvious diffraction peaks, indicating that the two-dimensional Cu-TCPP modified bimetallic MOF composite material has a long-range ordered crystal structure. A good crystal structure usually means more stable performance and higher sensitivity.

[0134] Detect the N of the two-dimensional Cu-TCPP modified bimetallic MOF composite material obtained in step (5) of Example 1 2Adsorption - desorption isotherm, the specific operation is as follows: First, place the two - dimensional Cu - TCPP - modified bimetallic MOF composite material obtained in step (5) of Example 1 in a specific surface area and porosity analyzer test device. Subsequently, perform degassing treatment on the two - dimensional Cu - TCPP - modified bimetallic MOF composite material at 120 °C to remove the impurity gases adsorbed on the surface of the two - dimensional Cu - TCPP - modified bimetallic MOF composite material. Then, introduce nitrogen as the adsorbate into the test system. By precisely controlling the partial pressure of nitrogen, gradually increase the nitrogen concentration, and record the adsorption amount of nitrogen by the composite material at different nitrogen concentrations. After completing the measurement of the adsorption process, gradually reduce the nitrogen concentration and conduct the measurement of the desorption process, recording the release amount of nitrogen during the desorption process. By plotting the relationship curve between the adsorption amount and the nitrogen partial pressure, the N 2 Adsorption - desorption isotherm.

[0135] N 2 The adsorption - desorption isotherm is as Figure 4 shown. From Figure 4 it can be seen that the two - dimensional Cu - TCPP - modified bimetallic MOF composite gas - sensitive material has a specific surface area as high as 1168 m 2 / g, significantly enhancing its gas adsorption capacity. In the test of the N 2 adsorption - desorption isotherm, a slight hysteresis phenomenon appears in the desorption stage, which reveals that the two - dimensional Cu - TCPP - modified bimetallic MOF composite material contains mesoporous and macroporous structures. These pores not only greatly increase the number of adsorption sites for hydrogen molecules but also optimize the diffusion path of gas molecules inside the material, promoting the effective transmission of gas, thus achieving high - sensitivity and low - concentration detection of hydrogen.

[0136] Test Example 4

[0137] As the target gas molecules are adsorbed on the surface of the gas - sensitive sensor, electrons transfer from the sensor material to the target molecules, resulting in a change in the resistance of the gas - sensitive sensor. This change can be converted into an electrical signal for output, thereby realizing the detection of the target gas. This test example evaluates the gas - sensitive performance of the gas - sensitive sensor for the dissolved gas H 2 in transformer oil.

[0138] Detect the gas - sensitive sensor of Example 10 for 2 ppm H 2Response curve: First, place the gas sensor of Example 10 in a test chamber with a controllable atmosphere. Subsequently, inject a mixed gas containing 2 ppm hydrogen concentration (usually using nitrogen or air as the balance gas) into the test chamber through a precise gas flow controller. At the same time, use a high-precision temperature and humidity control system to maintain the stability and consistency of the test environment, and detect the response values of the gas sensor of Example 10 to 2 ppm H 2 at different temperatures and obtain the response curve, as shown in Figure 5 . It can be seen from Figure 5 that as the temperature increases, the response value of the gas sensor of Example 10 first increases and then decreases. The gas sensor of Example 10 has a maximum response value of 62 when the working temperature is 90 °C for H 2 ;

[0139] Among them, the response value is calculated using the calculation formula for n-type semiconductor gas sensors: S = R g / R a , where S is the response value, R g is the resistance value of the gas sensor in air, and R a is the resistance value of the gas sensor in the gas to be measured;

[0140] According to the same method, the response curves of the gas sensors of Examples 11-13, and the gas sensors of Comparative Examples 2, 4, and 6 to 2 ppm H 2 were detected respectively. It was found that the trends of the response curves of the gas sensors of Examples 11-13, and the gas sensors of Comparative Examples 2, 4, and 6 to 2 ppm H 2 are similar to the response curve of the gas sensor of Example 10 to 2 ppm H 2 , that is, as the temperature increases, the response value of the gas sensor first increases and then decreases, and when the working temperature is 90 °C, the response value reaches the maximum. The specific maximum response values are shown in Table 1.

[0141] Table 1

[0142]

[0143] From the results in Table 1, it can be seen that the gas sensor of Example 10 uses a bimetallic Zn / Co-MOF material as the substrate and is modified with two-dimensional Cu-TCPP nanosheets, showing the highest hydrogen response value (62), indicating that the combination of bimetallic MOF and two-dimensional Cu-TCPP nanosheets significantly improves the gas sensing performance of the material. The gas sensors prepared in the other examples also show good gas sensing performance.

[0144] The gas sensor of Comparative Example 2 only used Zn-MOF as the substrate and did not add cobalt element. Compared with Example 10, the maximum response value to hydrogen decreased to 34, indicating that the absence of cobalt element may affect the gas-sensing performance of the material.

[0145] The gas sensor of Comparative Example 4 only used Co-MOF as the substrate and did not add zinc element. The maximum response value to hydrogen in this example further decreased to 27, indicating that the absence of zinc element also has a negative impact on the gas-sensing performance.

[0146] The gas sensor of Comparative Example 6 did not prepare the bimetallic Zn / Co-MOF material and directly used two-dimensional Cu-TCPP nanosheets as the gas-sensing material. Although its maximum response value to hydrogen (40) is higher than that of Comparative Examples 2 and 4, it is still lower than that of Example 10, indicating that the presence of the bimetallic Zn / Co-MOF material plays an important role in improving the gas-sensing performance.

[0147] The high response value of the gas sensor in Example 10 indicates that the combination of two metal elements, Zn and Co, may produce a synergistic effect, optimizing the structure and performance of the material, thereby improving the sensitivity to hydrogen; at the same time, the modification of two-dimensional Cu-TCPP nanosheets improves the gas-sensing performance of the material, but the effect is not as significant as when combined with the bimetallic Zn / Co-MOF material. This may be because the two-dimensional nanosheets provide more active sites and catalytic activity, promoting the interaction with hydrogen molecules, and the combination of the bimetallic Zn / Co-MOF material and two-dimensional Cu-TCPP nanosheets may form a pore structure conducive to gas diffusion and adsorption, thereby improving the gas-sensing performance of the material.

[0148] In summary, the two-dimensional Cu-TCPP modified bimetallic MOF composite material in the examples exhibits excellent gas-sensing performance, which benefits from the combination of the bimetallic MOF and two-dimensional Cu-TCPP nanosheets and the possible synergistic effect between them. This discovery provides a new idea for the development of high-performance gas sensors.

[0149] It should be understood that the parts not detailed in this specification belong to the prior art.

[0150] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited thereto. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, including any other suitable combination of each technical feature. These simple modifications and combinations should also be regarded as the content disclosed by the present invention and fall within the protection scope of the present invention.

Claims

1. A two-dimensional Cu-TCPP modified bimetallic MOF composite material, characterized in that: The two-dimensional Cu-TCPP modified bimetallic MOF composite material comprises a Zn / Co-MOF material, and the surface of the Zn / Co-MOF material is modified with Cu-TCPP nanosheets.

2. The method for preparing the two-dimensional Cu-TCPP modified bimetallic MOF composite material according to claim 1, characterized in that: The following steps are involved: The zinc salt, the cobalt salt and the surfactant A are mixed with a solvent and stirred to obtain a solution A; Mix isophthalic acid and DMF, and stir to obtain solution B; The solution A is mixed with the solution B, and then subjected to a hydrothermal reaction. After the hydrothermal reaction is completed, the solution is cooled to obtain a material A. The material A is subjected to solid-liquid separation to obtain a solid product A. The solid product A is washed and dried to obtain a Zn / Co-MOF material. The Zn / Co-MOF material is mixed with a mixed solvent of DMF and ethanol, and a Zn / Co-MOF dispersion is obtained after ultrasonic treatment, and a copper salt, a surfactant B and meso-tetrakis(4-carboxyphenyl)porphine are mixed with the Zn / Co-MOF dispersion to obtain a mixed material; The mixed material is reacted, cooled after the reaction is completed to obtain material B, the material B is subjected to solid-liquid separation to obtain a solid product B, and the solid product B is washed and dried to obtain a two-dimensional Cu-TCPP modified bimetallic MOF composite material.

3. The preparation method according to claim 2, characterized in that: Mixing zinc salt, cobalt salt and surfactant A with a solvent, wherein the weight ratio of the zinc salt, cobalt salt and surfactant A is 1:1:15-20; and / or The ratio of the total weight of the zinc salt, the cobalt salt and the surfactant A to the volume of the solvent is 1 g: 15 to 30 mL.

4. The preparation method according to claim 2 or 3, characterized in that: The zinc salt is selected from one or more of zinc nitrate, zinc chloride, zinc sulfate and zinc carbonate; and / or The cobalt salt is selected from one or more of cobalt nitrate, cobalt chloride, cobalt acetate and cobalt sulfate; and / or The surfactant A is selected from one or more of polyvinyl pyrrolidone, polyethylene glycol, sodium lauryl sulfate and polysorbate; and / or The solvent contains water and anhydrous alcohol, and the volume ratio of water to anhydrous alcohol is 1:1-2; and / or The anhydrous alcohol is anhydrous methanol and / or anhydrous ethanol.

5. The preparation method according to claim 2 or 3, characterized in that: The zinc salt, the cobalt salt and the surfactant A are mixed with the solvent, and stirred at a stirring speed of 300 to 500 rpm for 15 to 30 minutes to obtain a solution A.

6. The preparation method according to claim 2, characterized in that: Mixing isophthalic acid and DMF, stirring at a stirring speed of 300 to 800 rpm for 15 to 20 min to obtain a solution B; and / or The solid-liquid ratio of isophthalic acid to DMF is 0.1 g: 20-30 mL.

7. The preparation method according to claim 2, characterized in that: The volume ratio of solution A to solution B is 1:1-2; and / or The conditions of the hydrothermal reaction include: a temperature of 120 to 180° C. and a time of 12 to 18 hours; and / or The solid product A is washed and dried, and the drying conditions include: a temperature of 60 to 80° C. and a drying time of 12 to 24 hours.

8. The preparation method according to claim 2, characterized in that: In the mixed solvent of DMF and ethanol, the volume ratio of DMF to ethanol is 2 to 4:1; and / or Mixing the Zn / Co-MOF material with a mixed solvent of DMF and ethanol, wherein the solid-liquid ratio of the Zn / Co-MOF material to the mixed solvent of DMF and ethanol is 0.1-0.2 g:120 mL; and / or The ultrasonic conditions include: time of 20 to 60 minutes and power of 200 to 500W.

9. The preparation method according to claim 2 or 8, characterized in that: The specific operation of mixing the copper salt, surfactant B and meso-tetrakis(4-carboxyphenyl)porphine with the Zn / Co-MOF dispersion to obtain a mixed material includes: mixing the copper salt and surfactant B with the Zn / Co-MOF dispersion, stirring for 15 to 30 minutes to obtain a copper-containing dispersion, and then mixing meso-tetrakis(4-carboxyphenyl)porphine with the copper-containing dispersion, stirring at a stirring speed of 300 to 800 rpm for 5 to 15 minutes to obtain a mixed material; and / or wherein the weight ratio of the copper salt, the surfactant B and meso-tetrakis(4-carboxyphenyl)porphine is 1:3 to 5:1; and / or The weight ratio of the Zn / Co-MOF material, the copper salt, the surfactant B and meso-tetrakis(4-carboxyphenyl)porphine is 4-6:1:3-5:1; and / or The copper salt is selected from one or more of copper nitrate, copper chloride and copper sulfate; and / or The surfactant B is selected from one or more of polyvinyl pyrrolidone, polyethylene glycol, sodium lauryl sulfate and polysorbate.

10. The preparation method according to claim 2, characterized in that: The reaction conditions include: temperature of 80-120°C and time of 3-6h; and / or The solid product B is washed and dried, and the drying conditions include: 60-80° C. and a drying time of 12-24 hours.

11. Use of the two-dimensional Cu-TCPP modified bimetallic MOF composite material according to claim 1 in a gas sensor.

12. A gas sensor, characterized in that: The surface of the ceramic tube electrode of the gas sensor is coated with the two-dimensional Cu-TCPP modified bimetallic MOF composite material according to claim 1.

13. A method for preparing the gas sensor according to claim 12, characterized in that: The following steps are involved: Mixing terpineol and a polymer binder to obtain a mixed binder, grinding a two-dimensional Cu-TCPP modified bimetallic MOF composite material, and mixing the two-dimensional Cu-TCPP modified bimetallic MOF composite material with the mixed binder to obtain a gas-sensitive slurry; The ceramic tube electrode is cleaned and then dried, and then the gas-sensitive slurry is coated on the surface of the dried ceramic tube electrode to obtain a ceramic tube electrode coated with the gas-sensitive slurry. The ceramic tube electrode coated with the gas-sensitive slurry is dried, and then a nickel-chromium heating wire is inserted into the dried ceramic tube electrode. The platinum wire and the nickel-chromium heating wire on the dried ceramic tube electrode are then welded to a six-pin socket, and then aged to obtain a gas sensor.

14. The preparation method according to claim 13, characterized in that: The polymer binder is selected from one or more of ethyl cellulose, polyurethane and polystyrene; and / or The weight ratio of terpineol to polymer adhesive is 95-99:1; and / or The grinding time is 10 to 15 minutes; and / or The weight ratio of the two-dimensional Cu-TCPP modified bimetallic MOF composite material to the mixed adhesive is 1:20-50; and / or The drying conditions include: a temperature of 60 to 80° C. and a time of 12 to 24 hours; and / or The drying conditions include: a temperature of 60 to 80° C. and a drying time of 12 to 24 hours.

15. Use of the gas sensor according to claim 12 in hydrogen detection.

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