Working electrode for detecting tetrahydrothiophene, preparation method and electrochemical sensor
The working electrode prepared by ultrasonic spraying, combined with an iridium catalyst, solves the problem that existing detection methods cannot monitor in real time, and achieves highly selective and stable detection of tetrahydrothiophene, making it suitable for industrial sites.
Patent Information
- Application Number
- CN202510880801.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-27
- Publication Date
- 2025-09-09
AI Technical Summary
Existing tetrahydrothiophene detection methods require the use of large instruments, cannot achieve real-time monitoring, and are not suitable for the complex environments of industrial sites.
The working electrode was prepared by ultrasonic spraying method, using iridium as metal catalyst, combined with conductive agent, binder and dispersant, and sprayed on the waterproof and breathable membrane through suspension to prepare a highly sensitive and stable working electrode.
It achieves highly selective and highly stable detection of tetrahydrothiophene, avoids baseline fluctuations, improves the signal sensitivity and stability of the electrochemical sensor, and is suitable for real-time monitoring in industrial sites.
Smart Images
Figure CN120609880A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of electrochemical sensors, and particularly relates to a working electrode for detecting tetrahydrothiophene, a preparation method thereof, and an electrochemical sensor. Background Art
[0002] Tetrahydrothiophene (THP) is an industrial pollutant whose detection is particularly important due to its toxicity and recalcitrance. THT is also an organic compound primarily used as an odorant for fuel gases such as city gas, liquefied petroleum gas, and natural gas, and can also be used as a raw material for pharmaceuticals and pesticides. In the field of detection, gas chromatography and high-performance liquid chromatography (HPLC) are widely considered to be two efficient and accurate methods. For GC, the sample must first be sealed and the appropriate amount of reactants and stabilizers added. Gas chromatograph parameters, such as the column and temperature, are then set based on the sample's characteristics. The ionization detector accurately measures the THT content in the sample. HPLC, on the other hand, is renowned for its simple pretreatment, ease of operation, and high detection accuracy. Sample preparation and solution extraction in HPLC are typically performed by specialized analytical laboratories. Subsequently, HPLC parameters, such as the column and flow rate, are set based on the sample's characteristics, allowing for precise detection of THT. Both of these detection methods require large instruments, making them incapable of online, real-time environmental monitoring. They also suffer from long detection times and inability to handle complex environments, making them unsuitable for monitoring complex industrial environments. Therefore, developing a highly selective and stable tetrahydrothiophene gas sensor is an urgent need to ensure industrial safety. Summary of the Invention
[0003] The first object of the present invention is to provide a working electrode for detecting tetrahydrothiophene to solve the technical problem that the existing tetrahydrothiophene detection method requires the use of large instruments and cannot achieve real-time monitoring.
[0004] The second object of the present invention is to provide a method for preparing a working electrode for detecting tetrahydrothiophene.
[0005] A third object of the present invention is to provide an electrochemical sensor having a working electrode for detecting tetrahydrothiophene.
[0006] In order to achieve the above objectives, the technical solution adopted by the present invention is:
[0007] A method for preparing a working electrode for detecting tetrahydrothiophene comprises the following steps: mixing a metal catalyst, a conductive agent and a solvent, then adding a dispersant and a binder to obtain a slurry, mixing the slurry with a diluent to obtain a suspension, spraying the suspension onto a waterproof breathable membrane, drying and pressing to obtain the electrode.
[0008] Furthermore, the suspension is sprayed by ultrasonic spraying, and the spraying speed of the suspension is 5 to 100 mm / s.
[0009] Furthermore, the suspension is continuously heated during spraying, and the heating temperature is 100-200°C.
[0010] Furthermore, the specific surface area of the metal catalyst is 12 to 25 m 2 / g, D50 is 3~18μm.
[0011] Furthermore, the solvent is water, the metal catalyst is iridium; the conductive agent is one or more of graphite, carbon black, and graphene; the binder is one or more of polyvinylidene fluoride, carboxymethyl cellulose, polymethyl methacrylate, polyacrylonitrile, and polyacrylic acid; the dispersant is one or more of polytetrafluoroethylene emulsion and perfluorosulfonic acid polymer solution; and the diluent is one or more of methanol, ethanol, and isobutanol.
[0012] Furthermore, the mass ratio of the metal catalyst to the conductive agent is 1:1~10; the mass ratio of the metal catalyst to the binder is 0.1:0.2~0.4; the mass ratio of the metal catalyst to the diluent is 0.1:0.2~1; the mass ratio of the metal catalyst to the solvent is 0.1:0.2~2; the total mass of the metal catalyst, solvent, binder and diluent to the volume ratio of the dispersant is 1:0.3~0.6.
[0013] Furthermore, the mass fraction of the perfluorosulfonic acid polymer solution is 5-20%, and the solid content of the polytetrafluoroethylene emulsion is 10-30%.
[0014] Furthermore, the drying temperature is 200-300° C., the drying time is 30-120 min, and the pressing pressure is 0.3-0.6 MPa.
[0015] A working electrode for detecting tetrahydrothiophene is prepared by using the above-mentioned method for preparing a working electrode for detecting tetrahydrothiophene.
[0016] An electrochemical sensor for detecting tetrahydrothiophene, comprising the above-mentioned working electrode for detecting tetrahydrothiophene. Beneficial effects of the present invention:
[0017] The present invention utilizes ultrasonic spraying to prepare the working electrode. The high-frequency ultrasonic vibrations of the suspension disaggregate the particles within the suspension, providing excellent adhesion and a uniform coating. As can be seen from Example 1 and Comparative Example 3, the working electrode prepared using ultrasonic spraying exhibits higher signal sensitivity and lower signal noise than that prepared using screen printing. This contributes to a more stable electrochemical sensor during operation, reduces baseline fluctuations, and prevents false alarms.
[0018] The present invention uses iridium (Ir) as a metal catalyst. Compared with platinum (Pt) black and gold (Au) powder, the signal sensitivity of Ir is far superior to that of Pt black and Au powder, and it is the optimal catalyst for tetrahydrothiophene electrochemical sensors.
[0019] The working electrode prepared by ultrasonic spraying requires the metal catalyst to be suspended in the slurry to prevent the metal catalyst from sinking to the bottom and causing uneven distribution. The present invention selects a suitable particle size of the metal catalyst and a suitable dispersion liquid. During spraying, the high-frequency vibration of ultrasonic spraying is used to deagglomerate the particles in the slurry, so that the slurry has good adhesion and is sprayed evenly. BRIEF DESCRIPTION OF THE DRAWINGS
[0020] Figure 1 This is a physical picture of the electrode prepared by traditional screen printing method;
[0021] Figure 2 This is a physical picture of the working electrode for detecting tetrahydrothiophene in Example 1;
[0022] Figure 3 Graph showing the signal responses of the working electrodes of Example 1 and Comparative Examples 1-3 to tetrahydrothiophene;
[0023] Figure 4 This is a linear response diagram of the working electrode used to detect tetrahydrothiophene in Example 1 to tetrahydrothiophene. DETAILED DESCRIPTION
[0024] The present invention will be further described below with reference to the embodiments of the present invention and the accompanying drawings.
[0025] Example 1
[0026] The preparation method of the working electrode for detecting tetrahydrothiophene of embodiment 1 is: 0.1g of Ir black, 0.15g of carbon black are mixed and then 0.2mL of water is added to wet, then 0.4g of polyacrylonitrile, 0.3mL of polytetrafluoroethylene emulsion (PTFE emulsion) are added and mixed and stirred in a vacuum deaerator to obtain a slurry, after adding 0.2g of methanol in the slurry, a magnetic stirrer is used to stir and obtain a suspension. Polytetrafluoroethylene film is fixed on the substrate of the spraying equipment, and the suspension is placed on the pipe interface of the ultrasonic spraying machine. After the air in the ultrasonic spraying machine equipment pipe is discharged, the suspension is evenly sprayed on the polytetrafluoroethylene film at a speed of 5mm / s, and is continuously heated to 180°C during the spraying process so that the liquid is volatilized. After spraying, the polytetrafluoroethylene film is removed and transferred to a baking oven, which is warming up to 200°C and kept in heat for 40min. Then, the film is pressed under a pressure of 0.6MPa to obtain a working electrode. The specific surface area of Ir black is 15 to 25 m 2 / g, D50 is 3-6 μm, and the solid content of the polytetrafluoroethylene emulsion is 30%.
[0027] The preparation method of the reference electrode and the counter electrode is the same as that of the working electrode, and the metal catalyst used in the reference electrode and the counter electrode is platinum black.
[0028] Example 2
[0029] The preparation method of the working electrode for detecting tetrahydrothiophene in Example 2 is substantially the same as that in Example 1, except that the specific surface area of the Ir black in Example 2 is 12 to 17 m 2 / g, D50 is 12~18μm.
[0030] Table 1 Working electrode performance of Examples 1 to 2
[0031] <![CDATA[Specific surface area (m 2 / g)]]> Sensitivity (nA / ppm) Response time (s) <![CDATA[100 ppm H2S cross response]]> 15～25 220 15 30 12～17 100 15 60
[0032] As can be seen from Table 1, the specific surface areas are 15-25 and 12-17 m 2 / g of Ir black can be firmly attached to the polytetrafluoroethylene membrane by ultrasonic spraying, and there is no obvious difference in the sensitivity and response time performance of the obtained working electrodes.
[0033] Example 3
[0034] The preparation method of the working electrode for detecting tetrahydrothiophene in Example 3 is substantially the same as that in Example 1, except that the amount of polytetrafluoroethylene emulsion added in Example 3 is 0.4 mL.
[0035] Example 4
[0036] The preparation method of the working electrode for detecting tetrahydrothiophene in Example 4 is substantially the same as that in Example 1, except that in Example 4, the amount of Ir black added is 0.1 g, the amount of graphite added is 0.1 g, the amount of polyvinylidene fluoride added is 0.2 g, the amount of water added is 2 mL, the amount of ethanol added is 1 g, and the amount of perfluorosulfonic acid polymer solution (Nafion solution) added is 2 mL. The mass fraction of the perfluorosulfonic acid polymer solution is 20%.
[0037] Comparative Example 1
[0038] The preparation method of the working electrode for detecting tetrahydrothiophene in Comparative Example 1 is substantially the same as that in Example 1, except that the metal catalyst in Comparative Example 1 is platinum black, and the specific surface area of platinum black is 25 to 30 m 2 / g, D50 is 13~16μm.
[0039] Comparative Example 2
[0040] The preparation method of the working electrode for detecting tetrahydrothiophene in Comparative Example 2 is substantially the same as that in Example 1, except that the metal catalyst in Comparative Example 2 is gold powder, and the specific surface area of the gold powder is 30 to 35 m 2 / g, D50 is 1~5μm.
[0041] Comparative Example 3
[0042] The preparation method of the working electrode for detecting tetrahydrothiophene in Comparative Example 3 is substantially the same as that in Example 1, except that the slurry in Comparative Example 3 is applied on the waterproof breathable membrane by screen printing.
[0043] from Figure 1 It can be seen that the working electrode prepared by screen printing has irregular shape and is easy to separate from the base material. However, the working electrode prepared by ultrasonic spraying has a very strong peeling strength, and the slurry can be firmly attached to the waterproof and breathable membrane. Figure 3 It can be seen that the signal sensitivity of the working electrode obtained by ultrasonic spraying to tetrahydrothiophene is higher than that of the working electrode obtained by screen printing, and the signal noise obtained by the working electrode of Example 1 is small, which is due to the fact that the electrochemical sensor is more stable during operation, is less likely to generate baseline fluctuation signals, and will not generate false alarms. Figure 3 It can be seen that the signal sensitivity of Ir is much higher than that of Pt and Au in the working electrode prepared by ultrasonic spraying, and Ir is the best metal catalyst for tetrahydrothiophene electrochemical sensor. Figure 4 It can be seen that within the detection range, the working electrode of Example 1 shows an excellent linear relationship.
[0044] The proportions of various substances in the preparation methods of the working electrodes for detecting tetrahydrothiophene in Comparative Examples 4 to 9 are shown in Table 2.
[0045] Table 2 Proportions of the various substances in Comparative Examples 4 to 9
[0046]
[0047]
Claims
1. A method for preparing a working electrode for detecting tetrahydrothiophene, characterized in that: The following steps are involved: The metal catalyst, the conductive agent and the solvent are mixed, and then a dispersant and a binder are added and mixed to obtain a slurry. The slurry is mixed with a diluent to obtain a suspension. The suspension is sprayed onto a waterproof breathable membrane, dried and pressed.
2. The method for preparing a working electrode for detecting tetrahydrothiophene according to claim 1, wherein: The suspension is sprayed by ultrasonic spraying, and the spraying speed of the suspension is 5-100 mm / s.
3. The method for preparing a working electrode for detecting tetrahydrothiophene according to claim 1, wherein: The suspension is continuously heated during spraying, and the heating temperature is 100-200°C.
4. The method for preparing a working electrode for detecting tetrahydrothiophene according to claim 1, wherein: The specific surface area of the metal catalyst is 12 to 25 m 2 / g, D50 is 3~18μm.
5. The method for preparing a working electrode for detecting tetrahydrothiophene according to claim 1, wherein: The solvent is water, the metal catalyst is iridium; the conductive agent is one or more of graphite, carbon black, and graphene; the binder is one or more of polyvinylidene fluoride, carboxymethyl cellulose, polymethyl methacrylate, polyacrylonitrile, and polyacrylic acid; the dispersant is one or more of polytetrafluoroethylene emulsion and perfluorosulfonic acid polymer solution; and the diluent is one or more of methanol, ethanol, and isobutanol.
6. The method for preparing a working electrode for detecting tetrahydrothiophene according to claim 1, wherein: The mass ratio of the metal catalyst to the conductive agent is 1:1~10; the mass ratio of the metal catalyst to the binder is 0.1:0.2~0.4; the mass ratio of the metal catalyst to the diluent is 0.1:0.2~1; the mass ratio of the metal catalyst to the solvent is 0.1:0.2~2; the volume ratio of the total mass of the metal catalyst, solvent, binder and diluent to the dispersant is 1:0.3~0.
6.
7. The method for preparing a working electrode for detecting tetrahydrothiophene according to claim 5, characterized in that: The mass fraction of the perfluorosulfonic acid polymer solution is 5-20%, and the solid content of the polytetrafluoroethylene emulsion is 10-30%.
8. The method for preparing a working electrode for detecting tetrahydrothiophene according to claim 1, characterized in that: The drying temperature is 200-300° C., the drying time is 30-120 min; and the pressing pressure is 0.3-0.6 MPa.
9. A working electrode for detecting tetrahydrothiophene, characterized in that: The working electrode is prepared by the preparation method for detecting tetrahydrothiophene according to any one of claims 1 to 8.
10. An electrochemical sensor for detecting tetrahydrothiophene, characterized in that: The working electrode for detecting tetrahydrothiophene according to claim 9 is included.