Gas sensor for detecting characteristic decomposition components of gas and application of gas sensor

Abstract

The invention discloses application of a porous nano CuO / Cu2O material as a gas sensitive material for detecting characteristic decomposition components of insulating gas SF6 / N2. The invention also discloses a gas sensitive sensor, which is used for detecting the SF6 / N2 characteristic decomposition components and comprises the porous nano CuO / Cu2O material as the gas sensitive material for detecting the SF6 / N2 characteristic decomposition components of the insulating gas. In combination with a specific implementation mode, the porous nano CuO / Cu2O material disclosed by the invention has adsorption capacity on characteristic decomposition components of insulating gas SF6 / N2, and can be used as a gas sensitive material for detecting the characteristic decomposition components of the insulating gas SF6 / N2. Therefore, the porous nano CuO / Cu2O material can be used as a gas sensitive material for detecting the characteristic decomposition components of the insulating gas SF6 / N2, and can be applied to the field of SF6 / N2 decomposition detection. The porous nano CuO / Cu2O material is used for adsorbing SF6 / N2 gas characteristic decomposition components (such as NO2), a resistance change signal is generated, and detection is realized.

Description

Technical Field

[0001] The invention belongs to the technical field of online monitoring of electrical equipment, and in particular relates to a gas sensitive sensor for detecting characteristic decomposition components of a gas and an application thereof. Background Art

[0002] As an excellent insulating medium, sulfur hexafluoride (SF6) gas has been widely used in the power industry. However, SF6 has a very strong greenhouse effect, with a global warming potential (GWP) 23,500 times that of carbon dioxide and an atmospheric lifetime of 3,200 years. Therefore, reducing the use of SF6 or finding alternatives has become a research hotspot.

[0003] N2 is a colorless, odorless, non-toxic, non-polluting gas that is cheap and easy to obtain. Mixing SF6 with N2 can, on the one hand, effectively reduce the use of SF6 and reduce environmental damage, and on the other hand, it can maintain or approach the excellent insulation properties of pure SF6. In addition, the mixing ratio of SF6 / N2 mixed gas can be adjusted according to actual needs, so as to achieve a balance between insulation performance and environmental performance.

[0004] In practical applications, due to the presence of trace amounts of water and oxygen in the equipment, and possible discharge or overheating failures inside the equipment, SF6 / N2 gas will decompose to varying degrees, causing the production of a series of by-products, such as nitrogen dioxide (NO2), which will greatly reduce the insulation performance of the gas, leading to electrical equipment failures and even threatening the stable operation of the power grid. Therefore, it is necessary to prepare suitable sensors to monitor the presence of these gases.

[0005] Among them, resistive gas sensors have the advantages of long life, low cost, fast detection speed, small size and simple measurement system, and are currently the most commonly used method for detecting the decomposition components of the body. However, there are few studies on sensors for detecting the decomposition component of SF6 / N2 gas, NO2, and most of them require high temperature or ultraviolet working environment, which cannot meet the current low power consumption requirements of sensors for detecting gas decomposition components. Summary of the invention

[0006] 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.

[0007] In view of the above problems and / or the problems existing in the prior art, the present invention is proposed.

[0008] Therefore, the purpose of the present invention is to overcome the deficiencies in the prior art and provide a gas sensor for detecting characteristic decomposition components of a gas.

[0009] To solve the above technical problems, the present invention provides the following technical solutions: a gas sensor for detecting characteristic decomposition components of a gas, characterized in that the gas sensor comprises a porous nano-CuO / Cu2O material, wherein the CuO / Cu2O is uniformly and stably distributed on the crystal skeleton of Cu-BTC, and the Cu-BTC crystal is a regular octahedral skeleton.

[0010] Another object of the present invention is to overcome the deficiencies in the prior art and provide a method for preparing a gas sensor, which is characterized by comprising:

[0011] Dissolve copper nitrate in deionized water to obtain a 0.1 M copper ion solution;

[0012] Dissolve 1,3,5-benzenetricarboxylic acid in deionized water and stir until completely dissolved to obtain a BTC solution;

[0013] Slowly add 0.1 M copper ion solution to the BTC solution, stir until a precipitate is formed, centrifuge, collect the reaction product and repeatedly filter and wash;

[0014] The obtained product was vacuum dried to obtain Cu-BTC powder;

[0015] The Cu-BTC powder is calcined at high temperature and then cooled to room temperature to obtain porous nano-CuO / Cu2O material.

[0016] As a preferred embodiment of the preparation method of the present invention, the mass ratio of copper nitrate to 1,3,5-benzenetricarboxylic acid is 5:2.8.

[0017] As a preferred embodiment of the preparation method of the present invention, the obtained product is vacuum dried, wherein the drying temperature is 60-80° C. and the drying time is 6-10 hours.

[0018] As a preferred embodiment of the preparation method of the present invention, the Cu-BTC powder is calcined at a high temperature, wherein the calcination temperature is 400° C. and the calcination time is 2 hours.

[0019] As a preferred solution of the preparation method of the present invention, the porous nano-CuO / Cu2O material is distributed on the Cu-BTC crystal skeleton.

[0020] Another object of the present invention is to overcome the deficiencies in the prior art and provide an application of a gas sensor.

[0021] As a preferred solution of the application of the present invention, the porous nano-CuO / Cu2O material is used as a gas-sensitive material for detecting characteristic decomposition components of environmentally friendly insulating gas SF6 / N2.

[0022] As a preferred solution of the application of the present invention, the porous nano-CuO / Cu2O material adsorbs NO2, thereby realizing the detection of characteristic decomposition components of environmentally friendly insulating gas SF6 / N2.

[0023] As a preferred solution of the application of the present invention, when NO2 gas contacts the sensor, charge transfer occurs in the sensor, and the sensor responds to the gas by detecting the change in the resistance value of the sensor.

[0024] Beneficial effects of the present invention:

[0025] (1) The porous nano-CuO / Cu2O material proposed in the present invention as a composite gas-sensitive material can significantly improve the response and recovery time of the device;

[0026] (2) The gas sensor for characteristic decomposition components of SF6 / N2 gas based on porous nano-CuO / Cu2O materials proposed in the present invention can be used for reliability detection of gas insulation equipment operation and maintenance to avoid SF6 decomposition caused by discharge or overheating failure in the equipment;

[0027] (3) The gas sensor for characteristic decomposition components of SF6 / N2 gas based on porous nano-CuO / Cu2O materials proposed in the present invention can realize gas-sensitive detection at room temperature without the need for energy-consuming elements such as heating or ultraviolet rays;

[0028] (4) The porous nano-CuO / Cu2O material proposed in the present invention can be further extended to the preparation of other similar gas-sensitive materials, that is, the application of composite nano-materials obtained by calcining metal organic framework (MOF) materials in the field of gas sensing. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] 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:

[0030] Figure 1 This is a scanning electron microscope image of the Cu-BTC material of Example 1 of the present invention (magnification: ×2000).

[0031] Figure 2This is a scanning electron microscope image of the porous nano-CuO / Cu2O material of Example 1 of the present invention (magnification: ×6500).

[0032] Figure 3 3 is the resistance response curve of the sensor of Example 1 of the present invention to NO2 gas concentration.

[0033] Figure 4 It is the working curve of the sensor of Example 1 of the present invention. DETAILED DESCRIPTION

[0034] 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.

[0035] 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.

[0036] 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.

[0037] The raw materials used in the present invention: copper nitrate, deionized water, 1,3,5-benzenetricarboxylic acid are all purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.

[0038] Example 1

[0039] This embodiment provides a method for preparing a gas sensor for detecting characteristic decomposition components of a gas, comprising the following steps:

[0040] (1) Dissolve 5.0 g of copper nitrate (Cu(NO3)2·3H2O) in 150 mL of deionized water to obtain a 0.1 M copper ion solution;

[0041] (2) Dissolve 2.8 g of 1,3,5-benzenetricarboxylic acid in 50 mL of deionized water and stir until completely dissolved to obtain a BTC solution;

[0042] (3) Slowly adding the copper ion solution to the above BTC solution and stirring for about 3 hours until a precipitate is formed;

[0043] (4) centrifuging the obtained solution, collecting the reaction product, filtering and washing it repeatedly, placing it in a vacuum oven, and drying it at 60-80° C. for 6-10 h to obtain Cu-BTC powder;

[0044] (5) The powder is evenly spread in a high temperature resistant crucible, and the crucible is placed in a high temperature furnace at 400°C and calcined for 2 hours. During the calcination process, Cu-BTC will decompose and copper ions will be oxidized to generate CuO and Cu2O. After naturally cooling to room temperature, the desired porous nano-CuO / Cu2O material is finally obtained.

[0045] The gas-sensitive sensor material precursor Cu-BTC prepared in this example was characterized by scanning electron microscopy (SEM). Figure 1 As shown, it can be seen that the Cu-BTC crystal presents a regular octahedral skeleton;

[0046] The porous nano-CuO / Cu2O material obtained by calcining Cu-BTC in this example was characterized by scanning electron microscopy (SEM). Figure 2 As shown, it can be seen that CuO / Cu2O is evenly and stably distributed on the crystal framework of Cu-BTC.

[0047] Example 2

[0048] This embodiment provides an application of a gas sensor for detecting characteristic decomposition components of a gas, comprising the following steps:

[0049] The sensor prepared in Example 1 was placed in a resistance detection device (multimeter KEITHLEYDAQ6510) at room temperature, and after 30 minutes of SF6 / N2 background gas was introduced, NO2 gas with concentrations of 3ppm, 5ppm, 10ppm, 20ppm and 30ppm was introduced respectively until the resistance change of the sensor reached a peak value, and after introducing NO2 gas of different concentrations, SF6 / N2 gas was introduced again for recovery until the resistance of the sensor no longer changed. By testing the resistance change of the sensor, the concentration of NO2 gas can be detected.

[0050] Figure 3 30ppm, 20ppm, 10ppm, 5ppm and 3ppm of NO2 gas at room temperature are 91.7%, 75%, 38.3%, 28.8% and 23.8%, respectively.

[0051] Figure 4 is the working curve of the sensor of Example 1 of the present invention. It can be seen that the linearity between the sensor response and the concentration is good, R 2=0.975, and still has a good response to 3ppm NO2 gas, which can meet the use requirements of sensors for detecting NO2 gas or for monitoring the characteristic decomposition components of insulating gas SF6 / N2.

[0052] Example 3

[0053] The difference between this embodiment and embodiment 1 is that the dissolution in 150 mL of deionized water in step (1) is replaced by dissolution in 150 mL of anhydrous ethanol (Shanghai Aladdin Biochemical Technology Co., Ltd.), and the remaining steps are the same as in embodiment 1.

[0054] The sensor prepared in Example 3 was placed in a resistance detection device (multimeter KEITHLEYDAQ6510) at room temperature, and after 30 minutes of SF6 / N2 background gas was introduced, NO2 gas with concentrations of 3ppm, 5ppm, 10ppm, 20ppm and 30ppm was introduced respectively until the resistance change of the sensor reached a peak value, and after introducing NO2 gas with different concentrations, SF6 / N2 gas was introduced again to recover until the resistance of the sensor no longer changed. The results showed that the sensor response was unchanged from the results in Example 2.

[0055] Example 4

[0056] The difference between this embodiment and embodiment 1 is that the dissolution in 150 mL of deionized water in step (1) is replaced by dissolution in 150 mL of N,N-dimethylformamide (DMF) (Shanghai Aladdin Biochemical Technology Co., Ltd.), and the remaining steps are the same as in embodiment 1.

[0057] The sensor prepared in Example 4 was placed in a resistance detection device (multimeter KEITHLEYDAQ6510) at room temperature, and after 30 minutes of SF6 / N2 background gas was introduced, NO2 gas with concentrations of 3ppm, 5ppm, 10ppm, 20ppm and 30ppm was introduced respectively until the resistance change of the sensor reached a peak value, and after introducing NO2 gas with different concentrations, SF6 / N2 gas was introduced again to recover until the resistance of the sensor no longer changed. The results showed that the sensor response was unchanged from the results in Example 2.

[0058] Comparative Example 1

[0059] The difference between this embodiment and embodiment 1 is that the calcination for 2 h in step (5) is replaced by calcination for 1 h, and the remaining steps are the same as those in embodiment 1.

[0060] The sensor prepared in Comparative Example 1 was placed in a resistance detection device (multimeter KEITHLEYDAQ6510) at room temperature, and after 30 minutes of SF6 / N2 background gas was introduced, NO2 gas with concentrations of 3ppm, 5ppm, 10ppm, 20ppm and 30ppm was introduced respectively until the resistance change of the sensor reached a peak value, and after the NO2 gas with different concentrations was introduced, SF6 / N2 gas was introduced again to recover until the resistance of the sensor no longer changed. The results show that the response sensitivity of the sensor to 30ppm, 20ppm, 10ppm, 5ppm and 3ppm NO2 gas at room temperature is 64.2%, 47.7%, 31.5%, 19.1% and 12.3%, respectively. It can be seen that the sensor response sensitivity is reduced due to insufficient calcination time.

[0061] Comparative Example 2

[0062] The difference between this comparative example and Example 1 is that the calcination for 2 h in step (5) is replaced by calcination for 6 h, and the remaining steps are the same as those in Example 1.

[0063] The sensor prepared in Comparative Example 2 was placed in a resistance detection device (multimeter KEITHLEYDAQ6510) at room temperature, and after 30 minutes of SF6 / N2 background gas was introduced, NO2 gas with concentrations of 3ppm, 5ppm, 10ppm, 20ppm and 30ppm was introduced respectively until the resistance change of the sensor reached a peak value, and after the NO2 gas of different concentrations was introduced, SF6 / N2 gas was introduced again to recover until the resistance of the sensor no longer changed. The results show that the response sensitivity of the sensor to 30ppm, 20ppm, 10ppm, 5ppm and 3ppm NO2 gas at room temperature is 82.3%, 65.1%, 36.8%, 26.4% and 20.5%, respectively. It can be seen that the sensor response sensitivity decreases slightly after the calcination time increases further.

[0064] 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 sensor for detecting characteristic decomposition components of a gas, characterized in that: The gas sensor comprises porous nano CuO / Cu2O material, wherein CuO / Cu2O is evenly and stably distributed on the crystal skeleton of Cu-BTC, and the Cu-BTC crystal is a regular octahedral skeleton.

2. The method for preparing a gas sensor according to claim 1, wherein: include, Dissolve copper nitrate in deionized water to obtain a 0.1 M copper ion solution; Dissolve 1,3,5-benzenetricarboxylic acid in deionized water and stir until completely dissolved to obtain a BTC solution; Slowly add 0.1 M copper ion solution to the BTC solution, stir until a precipitate is formed, centrifuge, collect the reaction product and repeatedly filter and wash; The obtained product was vacuum dried to obtain Cu-BTC powder; The Cu-BTC powder is calcined at high temperature and then cooled to room temperature to obtain porous nano-CuO / Cu2O material.

3. The preparation method according to claim 2, characterized in that: The mass ratio of the copper nitrate to 1,3,5-benzenetricarboxylic acid is 5:2.

8.

4. The preparation method according to claim 2, characterized in that: The obtained product is vacuum dried, wherein the drying temperature is 60-80° C. and the drying time is 6-10 hours.

5. The preparation method according to claim 2, characterized in that: The Cu-BTC powder is calcined at a high temperature, wherein the calcination temperature is 400° C. and the calcination time is 2 hours.

6. The preparation method according to claim 2, characterized in that: The porous nano CuO / Cu2O material is distributed on the Cu-BTC crystal framework.

7. Use of the gas sensor prepared by the preparation method according to any one of claims 2 to 6.

8. The use according to claim 7, characterized in that: The porous nano CuO / Cu2O material is used as a gas-sensitive material for detecting characteristic decomposition components of environmentally friendly insulating gas SF6 / N2.

9. The use according to claim 8, characterized in that: The porous nano CuO / Cu2O material adsorbs NO2, thereby realizing the detection of characteristic decomposition components of environmentally friendly insulating gas SF6 / N2.

10. The use according to claim 9, characterized in that: When NO2 gas comes into contact with the sensor, charge transfer occurs in the sensor, and the sensor responds to the gas by detecting changes in the resistance value of the sensor.

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