阅读说明：本技术 一种so2f2气敏传感器 (SO (SO)2F2Gas sensor ) 是由 李丽 唐念 张曼君 黎晓淀 孙东伟 于 2020-12-31 设计创作，主要内容包括：本发明涉及传感器技术领域,尤其涉及一种SO-2F-2气敏传感器。本发明公开了一种SO-2F-2气敏传感器,该传感器将氧化铈-氧化镍复合物作为传感器的敏感层材料,相对于纯氧化铈基气敏传感器,本发明提供的气敏传感器的响应值和响应温度都都得到了优化,可以在低温下定性与定量检测硫酰氟,实现六氟化硫电气设备故障的准确判断。此外,本发明提供的气敏传感器结构简单,制备成本较低,可以携带到检测现场进行检测,提高了六氟化硫电气设备的状态诊断的及时性和准确性。(The invention relates to the technical field of sensors, in particular to a SO 2 F 2 A gas sensor. The invention discloses an SO 2 F 2 The gas sensor takes the cerium oxide-nickel oxide compound as a sensitive layer material of the sensor, and compared with a pure cerium oxide-based gas sensor, the response value and the response temperature of the gas sensor provided by the invention are optimized, and the sulfuryl fluoride can be qualitatively and quantitatively detected at a low temperature, so that the fault of sulfur hexafluoride electrical equipment can be accurately judged. In addition, the gas sensor provided by the invention has the advantages of simple structure and lower preparation cost, can be carried to a detection field for detection, and improves the timeliness and accuracy of state diagnosis of sulfur hexafluoride electrical equipment.)

1. SO (SO)₂F₂A gas sensor, comprising: the electrode and the sensitive layer material coated on the surface of the electrode;

the sensitive layer is made of a cerium oxide-nickel oxide compound.

2. SO according to claim 1₂F₂The gas sensor is characterized in that the preparation method of the cerium oxide-nickel oxide compound comprises the following steps:

mixing polyvinylpyrrolidone with a solvent, then adding a cerium source and a nickel source, then adding urea, mixing, carrying out hydrothermal reaction, and then calcining to obtain the cerium oxide-nickel oxide composite.

3. SO according to claim 2₂F₂The gas sensor is characterized in that the solvent is a mixed solution of deionized water and an organic solvent;

the organic solvent is one or more than two of ethanol, methanol and N, N-dimethylformamide.

4. SO according to claim 3₂F₂The gas sensor is characterized in that the volume ratio of the deionized water to the organic solvent is 5: 1-1: 10.

5. SO according to claim 2₂F₂The gas sensor is characterized in that the temperature of the hydrothermal reaction is 150-200 ℃ and the time is 17 h.

6. SO according to claim 2₂F₂The gas sensor is characterized in that the calcining temperature is 400-500 ℃ and the calcining time is 1-4 h.

7. SO according to claim 2₂F₂The gas sensor is characterized in that the cerium source is cerium salt, and the nickel source is nickel salt.

8. SO according to claim 2₂F₂The gas sensor is characterized in that the molar ratio of the cerium source raw material to the nickel source is 200: 1-1: 1;

the mass ratio of the urea to the polyvinylpyrrolidone is 1: 1.

9. SO according to claim 1₂F₂The gas sensor is characterized in that the coating amount of the sensitive layer material on the surface of the electrode is 1-30mg/cm²。

10. SO (SO)₂F₂The detection method of (2), characterized by comprising the steps of:

the SO according to any one of claims 1 to 9 is used at a temperature of 50 to 100 ℃₂F₂Gas sensor pair SO₂F₂And (6) detecting.

Technical Field

The invention relates to the technical field of sensors, in particular to a SO₂F₂A gas sensor.

Background

Partial discharge is caused after sulfur hexafluoride electrical equipment has fault defects, and insulating medium SF₆Reacting with water and oxygen to form H₂S，SO₂，SOF₂，SO₂F₂And the like. By detecting the components of the sulfur hexafluoride decomposition products, the fault reason, the discharge level, the development condition, the danger degree and the like of the electrical equipment can be judged, so that the safe operation of the whole power system is ensured. Wherein the SOF₂、SO₂F₂Although the photoacoustic spectrometry (PAS) and the gas chromatography-mass spectrometer can detect the decomposition products with high sensitivity, the current common detection method has the defects of high price, complex structure and the like, is only suitable for laboratory decomposition product testing, has limited application of field detection, and influences the timeliness and the accuracy of state diagnosis of sulfur hexafluoride electrical equipment.

Disclosure of Invention

In view of the above, the present invention provides a SO₂F₂Gas sensor, the sensor pair SO₂F₂The sensor is sensitive, has a high response value and a relatively low response temperature, has a simple structure, and can be carried to a detection site for detection.

The specific technical scheme is as follows:

the invention provides a SO₂F₂A gas sensor, comprising: the electrode and the sensitive layer material coated on the surface of the electrode;

the sensitive layer is made of a cerium oxide-nickel oxide compound.

Cerium element is a rare earth element which is widely applied, cerium oxide of the cerium element oxide is widely applied to the fields of polishing materials, fuel cells, catalysts and the like, the cerium oxide is an n-type semiconductor and has a unique fluorite crystal structure, and the valence state of the cerium element in the cerium oxide can be converted between +3 valence and +4 valence, so that the cerium oxide has a plurality of oxygen vacancies. Meanwhile, cerium element in the cerium oxide has good fluorine-affinity performance due to the unique electronic structure, and the performances enable the cerium oxide to have excellent gas-sensitive performance when detecting sulfuryl fluoride; in addition, the invention unexpectedly discovers that cerium oxide and nickel oxide can be compounded to form a heterojunction, so that the gas-sensitive performance is enhanced. The cerium oxide-nickel oxide compound is used as a sensitive layer material of the sensor, and compared with a pure cerium oxide-based gas sensor, the response value and the response temperature of the gas sensor provided by the invention are optimized, sulfuryl fluoride can be detected at low temperature, and the fault of sulfur hexafluoride electrical equipment can be accurately judged. In addition, the gas sensor provided by the invention has the advantages of simple structure and lower preparation cost, can be carried to a detection field for detection, and improves the timeliness and accuracy of state diagnosis of sulfur hexafluoride electrical equipment.

In the invention, the coating amount of the sensitive layer material on the surface of the electrode is 1-30mg/cm²Preferably 10mg/cm²。

In the present invention, the electrode is preferably an interdigital electrode, and more preferably an aluminum oxide interdigital electrode.

In the invention, the preparation method of the cerium oxide-nickel oxide compound comprises the following steps:

mixing polyvinylpyrrolidone with a solvent, then adding a cerium source and a nickel source, then adding urea and sodium sulfate, mixing, and carrying out hydrothermal reaction to obtain the cerium oxide-nickel oxide compound.

In the preparation process of the cerium oxide-nickel oxide compound, firstly, a cerium source, a nickel source and a solvent are mixed; the solvent is a mixed solution of deionized water and an organic solvent; the organic solvent is one or more than two of ethanol, methanol and N, N-dimethylformamide, and ethanol is preferred.

The volume ratio of the deionized water to the organic solvent is 5: 1-1: 10, preferably 1: 1; the cerium source is cerium salt, specifically one or two of cerous nitrate hexahydrate and cerous sulfate, and preferably cerous nitrate hexahydrate; the nickel source is nickel salt, specifically one or two of nickel acetate tetrahydrate and nickel nitrate, and preferably nickel acetate tetrahydrate; the molar ratio of the cerium source to the nickel source is 200: 1-1: 1, preferably 97: 3.

then adding urea and mixing; the mass ratio of the urea to the polyvinylpyrrolidone is 1: 1; the mixing is preferably carried out under ultrasonic and stirring conditions; the ultrasonic time is 10min to 60min, preferably 30min, the stirring is preferably magnetic stirring, and the magnetic stirring time is 10min to 120min, preferably 30 min.

After the mixture is mixed to form a clear light green solution, preferably pouring the solution into a polytetrafluoroethylene lining, and putting the polytetrafluoroethylene lining into a hydrothermal kettle for hydrothermal reaction; the temperature of the hydrothermal reaction is 150-200 ℃, the time is 17h, and the reaction is preferably carried out for 17h at 180 ℃.

After the reaction is finished, removing the supernatant of the reaction product, preferably washing the collected precipitate with water and absolute ethyl alcohol alternately three times, placing the precipitate in an oven at 60 ℃ for drying for 24 hours, and then grinding the dried product into uniform powder. The particle size of the powdery product is not particularly limited in the present invention, and the powdery product is ground into a powder having a size conventional in the art.

Finally, calcining the powdery product to obtain a cerium oxide-nickel oxide compound; the calcining temperature is 400-500 ℃, the calcining time is 1-4 h, and preferably, the calcining time is 2h at 450 ℃.

The invention also provides a SO₂F₂The detection method comprises the following steps:

under the condition of 50-100 ℃, the SO is adopted₂F₂Gas sensor pair SO₂F₂And (6) detecting.

In the present invention, SO₂F₂Preferably SO in an electric power system₂F₂。

The invention adopts a dynamic gas distribution method to test the cycle performance of the gas sensor, and uses SF to test₆As background gas, in SF₆SO accounting for 100ppm₂F₂The gas is detected for the target. During gas-sensitive test, nitrogen is firstly introduced to remove impurity gas, and then SF is introduced₆The gas is charged with 100ppm SO to obtain background gas resistance₂F₂And obtaining the resistance value of the target gas after stabilization. SO can be adjusted during specific tests₂F₂The concentration parameter (b) is 10ppm, 50ppm, 70ppm or other values. The test scheme corresponds to normal conditions and fault conditions in an actual GIS power system, and only SF in the system is available when the power system is in normal operation₆Gas, i.e. corresponding to background gas resistance, generating SO when partial discharge occurs in the GIS₂F₂The gas corresponds to a detection resistance value of the target gas.

According to the technical scheme, the invention has the following advantages:

the invention provides a SO₂F₂The gas sensor takes the cerium oxide-nickel oxide compound as a sensitive layer material of the sensor, and compared with a pure cerium oxide-based gas sensor, the response value and the response temperature of the gas sensor provided by the invention are optimized, sulfuryl fluoride can be quantitatively detected according to the change of the resistance value of the sensor at low temperature, and the accurate judgment of the fault of sulfur hexafluoride electrical equipment is realized. In addition, the gas sensor provided by the invention has the advantages of simple structure and lower preparation cost, can be carried to a detection field for detection, and improves the timeliness and accuracy of state diagnosis of sulfur hexafluoride electrical equipment.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without inventive exercise.

FIG. 1 is an XRD pattern of a cerium oxide-nickel oxide composite of example 1 of the present invention and a pure cerium oxide of comparative example 1;

FIG. 2 shows SO based on a cerium oxide-nickel oxide composite prepared in example 2 of the present invention₂F₂The structure schematic diagram of the gas sensor;

FIG. 3 is a response curve of a pure cerium oxide-based gas sensor prepared in example 2 of the present invention when performing a sulfuryl fluoride gas-sensitive test;

FIG. 4 shows the SO-based cerium oxide-nickel oxide composite obtained in example 2 of the present invention₂F₂Response curve of the gas sensor when the gas sensor carries out sulfuryl fluoride gas-sensitive test.

Detailed Description

In order to make the objects, features and advantages of the present invention more obvious and understandable, the technical solutions in the embodiments of the present invention will be clearly and completely described below, and it should be apparent that the embodiments described below are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example 1

The preparation of the sensitive layer material cerium oxide-nickel oxide composite of the embodiment:

1. 20ml of deionized water and 20ml of absolute ethanol were measured to form a mixed solution.

2. 1g of polyvinylpyrrolidone was weighed and slowly added to the above mixed solution.

3. 1g of urea was weighed out and dissolved in the above solution.

4. 0.97mol of cerium hexa-nitrate is weighed out and dissolved in the above solution.

5. 0.03mol of nickel acetate tetrahydrate is weighed out and dissolved in the above solution.

6. Ultrasonic stirring for 30min, and magnetic stirring for 30 min.

7. Transferring the mixture into a polytetrafluoroethylene lining to react for 17 hours at 180 ℃.

8. Washing with deionized water, ethanol, deionized water, and ethanol for 6 times, and centrifuging.

9. Oven drying at 60 deg.C for 24 hr, and grinding into uniform powder. Calcining the mixture in a tubular furnace at 450 ℃ for 2 hours to obtain the cerium oxide-nickel oxide compound.

As can be seen from fig. 1, the peak of nickel oxide could not be detected due to the low content of nickel oxide, but the intensity of the peak was significantly changed compared to that of pure cerium oxide, which indicates the success of the combination of cerium oxide and nickel oxide.

Comparative example 1

This example is the preparation of pure cerium oxide as a sensitive layer material:

1. 20ml of deionized water and 20ml of absolute ethanol were measured to form a mixed solution.

2. 1g of polyvinylpyrrolidone was weighed and slowly added to the above mixed solution.

3. 1g of urea was weighed out and dissolved in the above solution.

4. 0.97mol of cerium hexa-nitrate is weighed out and dissolved in the above solution.

5. Ultrasonic stirring for 30min, and magnetic stirring for 30 min.

6. Transferring the mixture into a polytetrafluoroethylene lining to react for 17 hours at 180 ℃.

7. Washing with deionized water, ethanol, deionized water, and ethanol for 6 times, and centrifuging.

8. Oven drying at 60 deg.C for 24 hr, and grinding into uniform powder. Calcining the mixture in a tubular furnace at 450 ℃ for 2 hours to obtain pure cerium oxide.

From fig. 1, it can be confirmed that pure cerium oxide was successfully obtained in this example.

Example 2

This example is the preparation of a gas sensor (as shown in FIG. 2)

10mg of the cerium oxide-nickel oxide composite obtained in example 1 and 10mg of the pure cerium oxide obtained in comparative example 1 were dispersed in absolute ethanol, and ground to prepare slurry, respectively, and the cerium oxide-nickel oxide composite or the pure cerium oxide was added at a concentration of 10mg/cm²The coating amount is respectively coated on the interdigital electrodes and dried.

Example 3

In this embodiment, two gas sensors prepared in embodiment 2 are placed in a CGS-MT gas sensitive test platform to detect sulfuryl fluoride, and the specific operations are as follows:

in CGS-MT operation, nitrogen is firstly introduced to clean the chamber, and SF is then introduced₆Gas, introducing SO after its resistance value is stabilized₂F₂Gas, when its resistance value is stabilized, SF is repeated₆With SO₂F₂The operation of (2) can test the cycle stability.

As shown in fig. 3 and 4, the gas sensing performance of the ceria-nickel oxide composite was improved compared to the pure nanoparticle ceria, which is shown by a lower detection temperature of 50 ℃ (pure ceria of 100 ℃) and a higher response value of 1.67 (pure ceria of 1.2).

The above-mentioned embodiments are only used for illustrating the technical solutions of the present invention, and not for limiting the same; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.