A sensor device, detection method and application for the leakage of environmentally friendly insulating gas perfluoroisobutane

Abstract

The application discloses a kind of sensor devices for environmental protection type insulating gas C4F7N leakage, detection method and application.This sensor device is with tin dioxide (SnO2) particle doped titanium carbide (Ti3C2T x ) flake as gas sensitive material (SnO2@Ti3C2T x ), again this material is covered to interdigital electrode by drop coating mode and forms gas sensitive sensor.In the gas sensitive material, SnO2 is as the sensitization unit of capture C4F7N molecule, Ti3C2T x As sensing layer substrate to reduce internal resistance, the synergistic effect between sensitization unit and substrate can significantly improve device response and recovery time and significantly reduce working temperature;The sensor can produce response within 3min in static leakage simulation, and reach stable within 40min.The application introduces tin dioxide in titanium carbide by hydrothermal method, significantly improves the reaction activity of material to C4F7N, so that it has lower working temperature and higher sensitivity, has obvious advantage in the aspect of detecting C4F7N leakage at room temperature.

Description

Technical Field

[0001] This invention belongs to the fields of high voltage and insulation technology and gas sensing, specifically relating to a gas sensor device, detection method and application for detecting environmentally friendly insulating gas C4F7N. Background Technology

[0002] SF6 is a commonly used insulating gas in the power industry, possessing excellent insulation and arc-extinguishing properties. However, SF6 is also a gas with a strong greenhouse effect. To reduce the power system's dependence on SF6, industry experts have begun searching for new environmentally friendly gases as insulating media in power systems. Among them, C4F7N, as a new type of environmentally friendly gas, has insulation performance 2.2 times that of SF6, while its potential greenhouse effect is only 1 / 11 of SF6, showing extremely high application potential. However, related research shows that the most widely used EPDM rubber seals in power systems react to C4F7N to a certain extent. This reaction will corrode the surface of the seals, leading to the risk of gas leakage from the equipment.

[0003] Furthermore, given the relatively long operation and maintenance cycle of gas-insulated equipment, gas leaks (annual leak rate of 0.5%) are also possible due to other uncertainties. Additionally, the median lethal concentration (LC50) of C4F7N is 1000-15000 ppm, posing a potential threat to the respiratory system of living organisms. Therefore, in the early stages of the application of C4F7N-insulated equipment, there is an urgent need to develop a gas sensor that is easy to prepare, low-cost, operates at room temperature, and possesses high sensitivity and selectivity for C4F7N to address potential leaks during equipment operation. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides an environmentally friendly insulating gas C4F7N gas sensor based on tin dioxide-doped titanium carbide, a detection method, and its application.

[0005] The specific technical solution adopted in this invention is as follows:

[0006] In a first aspect, the present invention provides a sensor for leakage of environmentally friendly insulating gas C4F7N, comprising interdigitated electrodes and a composite gas-sensitive material coated thereon; the composite gas-sensitive material is composed of granular tin dioxide and titanium carbide Ti3C2T as sensitizing units. x The sensing layer is formed by composite formation.

[0007] Furthermore, the composite gas-sensitive material is formed by growing particulate tin dioxide on the surface of titanium carbide sheets.

[0008] Furthermore, the interdigitated electrode is fabricated by gold sputtering using a magnetron sputtering machine. Preferably, the interdigitated electrode comprises six pairs of interdigitates, each 11 mm long, with a spacing of 0.5 mm between each interdigitate.

[0009] Furthermore, the preparation method of the composite gas-sensitive material includes the following steps:

[0010] S1, dissolve LiF powder completely in HCl solution, add Ti3AlC2 powder, and react until complete;

[0011] S2, collect the reaction product of S1, wash it, reconstitute the solid product into a solution, disperse it by ultrasonication in an ice bath, and centrifuge it again to obtain a few-layer titanium carbide solution.

[0012] S3, Dissolve SnCl4·5H2O in water and mix with a small layer of titanium carbide solution. Stir the mixture thoroughly and then heat until the reaction is complete.

[0013] S4. Collect the reaction product and repeatedly filter and wash it. Then freeze-dry it to obtain the final product.

[0014] Furthermore, in step S1, the mass ratio of LiF powder to Ti3AlC2 powder is 1.6:1.

[0015] Furthermore, in step S1, the concentration of hydrochloric acid is 12 mol / L, the reaction temperature is 45℃, and the reaction time is 48 h.

[0016] Furthermore, in step S3, the concentration of the few-layer titanium carbide solution is 0.5 mg / mL, the concentration of SnCl4·5H2O is 4 mg / mL, and the volume ratio of SnCl4·5H2O solution to few-layer titanium carbide solution is 1:2.

[0017] Furthermore, in step S3, the heating temperature is 180°C and the heating time is 12 hours.

[0018] Furthermore, the method for coating the composite gas-sensitive material onto the interdigital electrode is as follows: the prepared aqueous solution of the composite gas-sensitive material is uniformly dropped onto the surface of the interdigital electrode and then dried.

[0019] In a second aspect, the present invention provides a detection method for the sensor described in the first aspect, comprising the following steps: when C4F7N gas comes into contact with the sensor, the sensor undergoes charge transfer, and the gas is responded to by detecting the change in the resistance value of the sensor.

[0020] Secondly, the present invention provides an application of the sensor described in the first aspect for detecting leakage of environmentally friendly insulating gas C4F7N.

[0021] The principle of this invention is as follows:

[0022] In this invention, the tin dioxide-doped titanium carbide gas-sensitive material, upon contact with C4F7N gas molecules, exhibits a strong interaction between the tin dioxide in the gas-sensitive material and the -CN groups in the C4F7N molecules. This allows C4F7N molecules near the gas-sensitive material to adsorb onto the surface of the tin dioxide, resulting in charge transfer and a change in the conductivity of the gas-sensitive material, which manifests as a change in the sensor's resistance value at the operating end. However, since tin dioxide is a typical metal oxide semiconductor, it requires significant external energy to excite its internal electronic transitions. Titanium carbide, with its high carrier mobility, reduces the external energy required for the reaction and promotes charge exchange between the material and gas molecules after recombination with tin dioxide. This allows the sensor to operate at room temperature while also exhibiting faster response and recovery speeds.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0024] 1. The composite gas-sensitive material proposed in this invention comprises particulate tin dioxide (SnO2) and titanium carbide (Ti3C2T) as sensitizing units. x The synergistic effect between sensing layers can significantly improve the response and recovery time of the device and reduce the operating temperature (enabling room temperature detection);

[0025] 2. The SnO2@Ti3C2T proposed in this invention x The C4F7N sensor, constructed from composite gas-sensitive materials, can be used for leak monitoring and maintenance of environmentally friendly gas-insulated equipment, avoiding safety risks caused by gas leaks inside the equipment.

[0026] 3. The SnO2@Ti3C2T proposed in this invention x The preparation scheme for composite gas-sensitive materials can be further extended to the preparation of other similar gas-sensitive materials, enriching the application of metal oxide@metal carbonitride composite materials in the field of gas sensing. Attached Figure Description

[0027] Figure 1 The image shows the morphology of tin dioxide-doped titanium carbide (Example 1) provided by the present invention under a transmission electron microscope.

[0028] Figure 2 A physical diagram of the interdigitated electrode provided by this invention;

[0029] Figure 3 The response diagram of tin dioxide-doped titanium carbide (Example 1) to different concentrations of C4F7N at room temperature is compared with that of pure titanium carbide (Comparative Example 1) provided by the present invention.

[0030] Figure 4This is a comparison chart showing the selectivity of tin dioxide-doped titanium carbide (Example 1) to C4F7N and other different gases provided by the present invention.

[0031] Figure 5 This invention provides the response results of tin dioxide-doped titanium carbide (Example 1) in simulated C4F7N leakage detection, along with a schematic diagram of the simulation device; wherein, Figure 5 (a) is a schematic diagram of the simulation device. Figure 5 (b) is a graph showing the dynamic change response of resistance in the leakage simulation. Detailed Implementation

[0032] To clarify the technical solutions, advantages, and problems corresponding to this invention, the following detailed description is provided with accompanying drawings and specific embodiments. It should be noted that the specific embodiments described herein are only for explaining this invention and do not constitute any limitation on this invention.

[0033] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0034] Example 1

[0035] This embodiment provides a sensing detection method for leakage of environmentally friendly insulating gas C4F7N, which is prepared by covering interdigitated electrodes with a gas-sensitive material. The preparation method includes the following steps:

[0036] S1, 3.2 g of LiF powder was added to 40 mL of 12 mol / L HCl solution and stirred for 10 min. Subsequently, a total of 2 g of Ti3AlC2 powder was added to the LiF / HCl solution in small batches, and the reaction was carried out at 45 °C for a total of 48 h.

[0037] S2. Collect the above reaction products, centrifuge and wash until the pH of the supernatant is 5-6, then use the solid product to prepare a solution of a certain concentration. After dispersing the solution by ultrasonication in an ice bath for 1 hour, centrifuge again to obtain a few-layer titanium carbide solution.

[0038] S3, take 40 mg of SnCl4·5H2O, disperse it in 10 mL of deionized water and mix it with 20 mL of 0.5 mg / mL few-layer titanium carbide solution. Stir the mixture at room temperature for 0.5 h and then transfer it to a 50 mL reactor and heat it at 180 °C for 12 h.

[0039] S4. The reaction products were collected and repeatedly filtered and washed. Finally, dry tin dioxide-doped titanium carbide was obtained under vacuum freezing conditions.

[0040] S5. Prepare a 0.2 mg / mL aqueous solution of tin dioxide-doped few-layer titanium carbide. Use a pipette to draw 100 μL and drop it onto the surface of the interdigital electrode. Then place the interdigital electrode coated with gas-sensitive material in a vacuum oven and dry it at 40 °C for 6 h to obtain the tin dioxide-doped titanium carbide C4F7N sensor.

[0041] Comparative Example 1

[0042] This embodiment provides a method for fabricating a pure titanium carbide sensor, used to compare the improved sensing response of a titanium carbide sensor doped with tin dioxide. The fabrication method includes the following steps:

[0043] S1, 3.2 g of LiF powder was added to 40 mL of 12 mol / L HCl solution and stirred for 10 min. Subsequently, a total of 2 g of Ti3AlC2 powder was added to the LiF / HCl solution in small batches, and the reaction was carried out at 45 °C for a total of 48 h.

[0044] S2. Collect the above reaction products, centrifuge and wash until the pH of the supernatant is 5-6, then use the solid product to prepare a solution of a certain concentration. After dispersing the solution by ultrasonication in an ice bath for 1 hour, centrifuge again to obtain a few-layer titanium carbide solution.

[0045] S3. Dilute the obtained few-layer titanium carbide to a 0.2 mg / mL aqueous solution, and use a pipette to draw 100 μL and drop it onto the surface of the interdigital electrode. Then place the interdigital electrode coated with gas-sensitive material in a vacuum oven and dry it at 40 °C for 6 h to obtain a pure titanium carbide C4F7N sensor.

[0046] Application Example 1

[0047] This embodiment provides an application of tin dioxide-doped titanium carbide and pure titanium carbide C4F7N sensors. Specifically, under room temperature conditions, the sensor is placed in a resistance detection device, and air is first introduced into the device for a period of time until the sensor's resistance stabilizes. Then, different concentrations of C4F7N gas are introduced into the device, and the change in sensor resistance is observed. When the response approaches saturation, the introduction of C4F7N gas is stopped. Figure 3 The response changes of titanium carbide before and after doping with tin dioxide are presented, showing that the presence of tin dioxide significantly improves the sensor's sensitivity to C4F7N. The sensor was able to produce an 8.8% (ΔR / R) response to 45 ppm C4F7N in the test. a ΔR is the change in resistance, R a The response (the resistance of the material in air) is given, and the operating temperature is room temperature. Furthermore, Figure 4The graph comparing the sensor's response to gases such as carbon dioxide, carbon monoxide, carbon disulfide, and acetylene at room temperature with its response to C4F7N shows that the sensor has strong selectivity for C4F7N.

[0048] Application Example 2

[0049] This embodiment provides an application of a tin dioxide-doped titanium carbide (C4F7N) sensor in a simulated C4F7N leakage environment. Specifically, at room temperature, the sensor is placed below a simulation device with a 1mm crack at the flange. Air is introduced into the simulation device for a period of time until the sensor's resistance stabilizes. Then, 100ppm of C4F7N is introduced into the device. When the sensor detects the leaked C4F7N, a change in resistance will occur. Figure 5 The diagram shows the dynamic change in resistance during leakage simulation. It can be seen that the sensor can detect leakage within 3 minutes and reach the maximum response value within 40 minutes.

[0050] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications, equivalent substitutions, and improvements made by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the invention.

Claims

1. A sensor device for detecting leakage of environmentally friendly insulating gas C4F7N, characterized in that: The sensor includes interdigitated electrodes and a composite gas-sensitive material coated thereon; the composite gas-sensitive material consists of granular tin dioxide and titanium carbide (Ti3C2T) as sensitizing units. x The sensing layer is formed by composite formation, and the composite gas-sensitive material is formed by growing particulate tin dioxide on the surface of titanium carbide sheet.

2. The application according to claim 1, characterized in that: The interdigitated electrodes were prepared by gold sputtering using a magnetron sputtering machine.

3. The application according to claim 1, characterized in that, The preparation method of the composite gas-sensitive material includes the following steps: S1, dissolve LiF powder completely in HCl solution, add Ti3AlC2 powder, and react until complete; S2, collect the reaction product of S1, wash it, re-prepare the solid product into a solution, then disperse it by ultrasonication in an ice bath, and centrifuge it again to obtain a few-layer titanium carbide solution. S3, Dissolve SnCl4•5H2O in water and mix with a small layer of titanium carbide solution. Stir the mixture thoroughly and then heat until the reaction is complete. S4. Collect the reaction product and repeatedly filter and wash it. Then freeze-dry it to obtain the final product.

4. The application according to claim 3, characterized in that: In step S1, the mass ratio of LiF powder to Ti3AlC2 powder is 1.6:

1.

5. The application according to claim 3, characterized in that: In step S3, the concentration of the few-layer titanium carbide solution is 0.5 mg / mL, the concentration of SnCl4•5H2O is 4 mg / mL, and the volume ratio of SnCl4•5H2O solution to few-layer titanium carbide solution is 1:

2.

6. The application according to claim 3, characterized in that: In step S3, the heating temperature is 180℃ and the heating time is 12h.

7. The application according to claim 1, characterized in that, The method for coating composite gas-sensitive materials onto interdigital electrodes is as follows: the prepared aqueous solution of composite gas-sensitive material is uniformly dropped onto the surface of the interdigital electrode and then dried.

8. The application according to claim 1, characterized in that, The method for detecting the environmentally friendly insulating gas C4F7N using the sensor includes the following steps: when C4F7N gas comes into contact with the sensor, the sensor undergoes charge transfer, and the gas is responded to by detecting the change in the sensor's resistance value.

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