An electrochemical acetylene sensor electrode, a preparation method thereof and an electrochemical acetylene sensor

Abstract

The application relates to the field of gas sensors, and particularly discloses an electrochemical acetylene sensor electrode, a preparation method thereof and an electrochemical acetylene sensor. The electrochemical acetylene sensor electrode comprises a polytetrafluoroethylene film and a slurry coated on the polytetrafluoroethylene film, wherein the slurry comprises nano gold particles, nano magnesium oxide, nano barium oxide, modified conductive carbon powder and a Nafion solution in a weight ratio of (0.47-0.50):(0.02-0.20):(0.02-0.18):(1-3):(0.6-2.0); and the modified conductive carbon powder is obtained by mixing potassium permanganate, deionized water and conductive carbon and then performing ball milling. The application realizes the effects of high sensitivity and high linearity of acetylene gas, greatly improves the selectivity of the electrochemical acetylene sensor, and has the advantages of low detection limit, high sensitivity and good selectivity.

Description

Technical Field

[0001] This application relates to the field of gas sensors, and more specifically, to an electrochemical acetylene sensor electrode, a method for preparing the same, and an electrochemical acetylene sensor. Background Technology

[0002] Acetylene gas, as an important basic raw material, is widely present in environments such as coal mines, high-voltage power systems, and chemical production, playing a crucial role in industrial production and energy supply. However, acetylene gas possesses characteristics such as high flammability, low flash point, and low explosion limit, making strict real-time monitoring of its concentration particularly important in practical applications. Accurate detection of acetylene gas concentration can effectively prevent explosions and other safety accidents, ensuring the safety of personnel and the normal operation of production equipment. With the continuous development of industry, the requirements for the accuracy, reliability, and timeliness of acetylene gas detection are becoming increasingly stringent.

[0003] Currently, the main sensors capable of detecting acetylene gas include catalytic combustion sensors, semiconductor sensors, and infrared sensors. Catalytic combustion sensors determine gas concentration by detecting the heat generated during the combustion of combustible gas in the presence of a catalyst; semiconductor sensors detect acetylene by utilizing the principle that the electrical properties of semiconductor materials change when they come into contact with gas; and infrared sensors measure gas concentration based on the absorption characteristics of gases to specific wavelengths of infrared light. These sensors can meet the needs of acetylene gas detection to a certain extent, but each also has its own limitations.

[0004] Catalytic combustion sensors typically require an LEL (Left-to-Least Explosive) level to detect acetylene gas and respond to all combustible gases, making them prone to false alarms and posing safety hazards in practical applications. Semiconductor sensors operate under continuous high temperatures, resulting in high energy consumption and significant safety risks. Furthermore, semiconductor sensors are susceptible to cross-interference gases, respond to all combustible gases, and are easily affected by temperature and humidity, leading to large signal fluctuations that compromise the accuracy and reliability of detection results. While infrared sensors offer advantages such as long lifespan, high sensitivity, and stability, their high cost and maintenance limits their application in cost-sensitive situations.

[0005] In addition to the types of sensors mentioned above, there is also an electrochemical gas sensor, which has advantages such as low energy consumption, good linearity, low cost, and long service life. However, sensors based on electrochemical principles for detecting acetylene gas are relatively rare on the market, and they are difficult to detect at low to medium concentrations, making it difficult to meet practical application needs. Summary of the Invention

[0006] To address the aforementioned technical problems, this application provides an electrochemical acetylene sensor electrode, its preparation method, and an electrochemical acetylene sensor. This electrochemical acetylene sensor has advantages such as good linearity, high sensitivity, good anti-cross-interference effect, and suitability for medium and low ranges, and has significant application value and significance.

[0007] Firstly, this application provides an electrochemical acetylene sensor electrode, which adopts the following technical solution:

[0008] An electrochemical acetylene sensor electrode includes a polytetrafluoroethylene (PTFE) membrane and a slurry coated on the PTFE membrane. The slurry comprises nano-gold particles, nano-magnesium oxide, nano-barium oxide, modified conductive carbon powder, and Nafion solution in a weight ratio of (0.47-0.50):(0.02-0.20):(0.02-0.18):(1-3):(0.6-2.0). The modified conductive carbon powder is obtained by ball milling a mixture of potassium permanganate, deionized water, and conductive carbon.

[0009] By adopting the above technical solution, the electrochemical acetylene sensor electrode of this application not only exhibits high sensitivity and excellent linearity to acetylene gas, but also maintains excellent signal output at low to medium concentrations. Furthermore, it shows almost no response to common interfering gases, demonstrating excellent resistance to cross-interference.

[0010] Specifically, this application incorporates modified conductive carbon powder into the slurry, which stabilizes the electrode's internal resistance and significantly improves the resistive characteristics of the final sensor. Furthermore, the conductive carbon powder, after oxidation with the strong oxidant potassium permanganate, exposes more active sites on its surface, facilitating the adhesion and dispersion of gold nanoparticles. Simultaneously, this application uses gold nanoparticles as the main catalytic active component. Due to their unique electronic structure, high specific surface area, and strong electron transfer effect, gold nanoparticles can rapidly promote the oxidative decomposition of acetylene gas molecules, thereby achieving a highly efficient and long-life reaction mechanism. Additionally, this application adds dibasic alkaline earth elements, nano-magnesium oxide and nano-barium oxide, to the slurry. With sodium chloride solution as the electrolyte, the nano-magnesium oxide and nano-barium oxide can weakly ionize and release OH-. - The use of ions suppresses the reaction of common acidic interfering gases such as hydrogen sulfide and sulfur dioxide, thereby reducing the influence of interfering gases on the sensor during operation, greatly improving the selectivity of the electrochemical acetylene sensor, and increasing the accuracy of detection.

[0011] Preferably, the slurry comprises nano-gold particles, nano-magnesium oxide, nano-barium oxide, modified conductive carbon powder, and Nafion solution in a weight ratio of (0.47-0.48):(0.05-0.10):(0.05-0.12):(1.0-2.1):(0.6-2.0).

[0012] Preferably, the weight ratio of potassium permanganate, deionized water and conductive carbon is (0.2-0.4):(6-12):1.

[0013] By adopting the above technical solution, this application optimizes the ratio of potassium permanganate, deionized water, and conductive carbon. This allows the conductive carbon powder to expose more active sites on its surface after oxidation by the strong oxidant potassium permanganate, which is beneficial for the adhesion and dispersion of gold nanoparticles. Simultaneously, it stabilizes the internal resistance of the electrode, greatly improving the resistive characteristics after assembly into a sensor. If there is too little potassium permanganate, the active sites exposed on the surface of the conductive carbon powder are insufficient, which is not conducive to the adhesion and dispersion of gold nanoparticles and makes it difficult to stabilize the internal resistance of the electrode. If there is too much potassium permanganate, it will over-oxidize the conductive carbon powder, destroying its structure and affecting the performance of the electrode and the stability of the sensor.

[0014] More preferably, the weight ratio of potassium permanganate, deionized water and conductive carbon is (0.25-0.30):(6-12):1.

[0015] Preferably, the conductive carbon powder has a particle size range of 1-3 μm and a spherical or near-spherical morphology.

[0016] Preferably, the nano-magnesium oxide and nano-barium oxide are spherical or near-spherical particles with a particle size in the range of 50-200 nm.

[0017] More preferably, the nano-magnesium oxide and nano-barium oxide are spherical or near-spherical particles with a particle size in the range of 50-80 nm.

[0018] Secondly, this application provides a method for preparing an electrochemical acetylene sensor electrode, which employs the following technical solution:

[0019] A method for preparing an electrochemical acetylene sensor electrode includes the following steps:

[0020] S1. After ultrasonically mixing potassium permanganate, deionized water and conductive carbon, the mixture is ground at a speed of 80-150 r / min for 4-6 h to obtain a ground solution. The ground solution is centrifuged, the lower precipitate is collected and washed with deionized water to obtain a solid. The solid is dried at a temperature of 60-80℃ for 4-8 h and passed through a 200-mesh sieve to obtain modified conductive carbon powder.

[0021] S2. Dissolve chloroauric acid in deionized water, add modified conductive carbon powder and mix ultrasonically. Add oxalic acid solution under stirring conditions in a water bath at 60-80℃ to carry out the reaction. After the reaction is completed, discard the supernatant to obtain a mixture of gold nanoparticles and modified conductive carbon powder.

[0022] S3. The mixture of nano-gold particles and modified conductive carbon powder, nano-magnesium oxide, nano-barium oxide and Nafion solution are ultrasonically mixed, and then ground at a speed of 50-200 r / min for 0.3-1.0 h to obtain a slurry;

[0023] S4. Coat the slurry onto a polytetrafluoroethylene membrane and dry it at 100-120℃ for 1-3 hours to obtain an electrochemical acetylene sensor electrode.

[0024] Preferably, in step S1, the centrifugation speed is 6000-8000 r / min and the centrifugation time is 5-8 min.

[0025] Preferably, in step S2, the weight ratio of chloroauric acid, deionized water, modified conductive carbon powder, and oxalic acid solution is 1:(30-50):(1-3):(45-60).

[0026] By adopting the above technical solution, this application optimizes the ratio of chloroauric acid, deionized water, modified conductive carbon powder, and oxalic acid solution, enabling the gold nanoparticles to achieve good adhesion and dispersion on the modified conductive carbon powder. If there is too little modified conductive carbon powder, the gold nanoparticles will lack sufficient adhesion sites, resulting in uneven dispersion of the gold nanoparticles, which in turn reduces the catalytic activity against acetylene gas and decreases the sensor's sensitivity to acetylene. If there is too much modified conductive carbon powder, the relative content of other components in the slurry will decrease, affecting the overall performance of the slurry, leading to unstable electrode internal resistance, and also affecting the linearity and anti-interference ability of the sensor.

[0027] More preferably, in step S2, the weight ratio of chloroauric acid, deionized water, modified conductive carbon powder, and oxalic acid solution is 1:(30-50):(1.0-2.1):(45-55).

[0028] Preferably, in step S2, the stirring speed in the water bath is 600-800 r / min, and the reaction time in the water bath is 30-40 min.

[0029] Preferably, in step S2, the molar concentration of the oxalic acid solution is 0.2-0.3 mol / L.

[0030] In the scheme of this application, in step S4, the coating method is a coating method commonly used in the art, such as inkjet printing, roller coating, screen printing, roll forming, and molding. Preferably, screen printing or roll forming is used.

[0031] Thirdly, the electrochemical acetylene sensor provided in this application adopts the following technical solution:

[0032] An electrochemical acetylene sensor includes the aforementioned electrochemical acetylene sensor electrode.

[0033] In summary, this application has the following beneficial technical effects:

[0034] 1. This application uses nano-gold particles, modified conductive carbon powder, nano-magnesium oxide, nano-barium oxide, and Nafion solution to prepare a slurry, which is then coated onto a polytetrafluoroethylene membrane. This fully utilizes the synergistic effect between the components, resulting in an electrochemical acetylene sensor electrode that not only has high sensitivity and excellent linearity to acetylene gas, but also has excellent signal output at low to medium concentrations. At the same time, it has almost no response to common interfering gases, demonstrating excellent anti-cross-interference ability and has extremely broad application prospects.

[0035] 2. The preparation method of this application is simple, easy to operate, uses readily available raw materials, and has low cost, making it suitable for large-scale industrial production. Attached Figure Description

[0036] Figure 1 A scanning electron microscope image of the modified conductive carbon powder obtained in step S1 of Example 1.

[0037] Figure 2 The response recovery curves of Application Example 1 and Application Comparative Examples 2-4 in 0-40 ppm acetylene gas are shown.

[0038] Figure 3 The step ventilation and linear fitting curves in 0-100ppm acetylene gas are for application Example 1;

[0039] Figure 4 The cyclic adsorption-desorption curves for application example 1 in 40 ppm acetylene gas are shown. Detailed Implementation

[0040] Unless otherwise specified in this application, all conditions were performed under standard conditions or conditions recommended by the manufacturer. All reagents and instruments used, unless otherwise stated below, are commercially available products.

[0041] In this application, the conventional chemical reagents used were purchased from Sinopharm Chemical Reagent Co., Ltd., and were of AR analytical grade.

[0042] The conductive carbon is selected from one or more of Cabot R330, Cabot XC72, Ketjen Black EC300, and Birla R3000, with a particle size range of 1-3 μm and a spherical or near-spherical morphology.

[0043] Example 1;

[0044] A method for preparing an electrochemical acetylene sensor electrode includes the following steps:

[0045] S1. 4g potassium permanganate, 135g deionized water and 14.3g conductive carbon powder were ultrasonically mixed for 10min and then ground at 120r / min for 6h to obtain a ground solution. The ground solution was centrifuged at 8000r / min for 5min, the lower precipitate was collected and washed with deionized water to obtain a solid. The solid was dried at 80℃ for 6h and passed through a 200-mesh sieve to obtain modified conductive carbon powder.

[0046] S2. Dissolve 1g of chloroauric acid in 45mL of deionized water, add 1.8g of the modified conductive carbon powder obtained in step S1, and sonicate for 10min. Under the conditions of water bath stirring at 60℃ and 750r / min, add 48mL of oxalic acid solution with a molar concentration of 0.2mol / L dropwise. After the oxalic acid solution is added, continue stirring in the water bath for 30min. After the reaction is completed, discard the supernatant to obtain a mixture of gold nanoparticles and modified conductive carbon powder.

[0047] S3. A mixture of 2.28g of gold nanoparticles and modified conductive carbon powder, 0.08g of magnesium nanoparticles, 0.1g of barium nanoparticles and 1.6g of Nafion solution is ultrasonically mixed for 10min, and then ground at 200r / min for 0.5h to obtain a slurry.

[0048] S4. Coat the slurry onto a polytetrafluoroethylene membrane and dry it at 100°C for 2 hours. Weigh the membrane to confirm that the load of a single electrode is 0.1 g, thus obtaining the electrode for the electrochemical acetylene sensor.

[0049] Comparative Example 1;

[0050] The difference from Example 1 is that the slurry does not contain nano-gold particles, that is, step S2 is removed, and 1.8g of modified conductive carbon powder, 0.08g of nano-magnesium oxide, 0.1g of nano-barium oxide and 1.6g of Nafion solution are directly ultrasonically mixed, and the rest is the same as in Example 1.

[0051] Comparative Example 2;

[0052] The difference from Example 1 is that the slurry does not contain modified conductive carbon powder, that is, step S1 is removed, and the nano-gold particles of step S2 are directly prepared. Then, 0.48g of nano-gold particles, 0.08g of nano-magnesium oxide, 0.1g of nano-barium oxide and 1.6g of Nafion solution are ultrasonically mixed, and the rest is the same as in Example 1.

[0053] Comparative Example 3;

[0054] The difference from Example 1 is that the conductive carbon powder is not modified, that is, step S1 is removed, and the modified conductive carbon powder in step S2 is replaced with conductive carbon powder. The rest is the same as Example 1.

[0055] Comparative Example 4;

[0056] The difference from Example 1 is that the slurry does not contain nano-magnesium oxide and nano-barium oxide. Instead, 2.28g of nano-gold particles and modified conductive carbon powder are directly ultrasonically mixed with 1.6g of Nafion solution. The rest is the same as in Example 1.

[0057] Comparative Example 5;

[0058] The difference from Example 1 is that the slurry does not contain nano-barium oxide. Instead, 2.28g of nano-gold particles and a mixture of modified conductive carbon powder, 0.08g of nano-magnesium oxide and 1.6g of Nafion solution are ultrasonically mixed. The rest is the same as in Example 1.

[0059] Comparative Example 6;

[0060] The difference from Example 1 is that the slurry does not contain nano-magnesium oxide. Instead, 2.28g of nano-gold particles and a mixture of modified conductive carbon powder, 0.1g of nano-barium oxide and 1.6g of Nafion solution are ultrasonically mixed. The rest is the same as in Example 1.

[0061] Comparative Example 7;

[0062] The difference from Example 1 is that the amount of potassium permanganate used in step S1 is 2.6g, while the rest is the same as in Example 1.

[0063] Comparative Example 8;

[0064] The difference from Example 1 is that the amount of potassium permanganate used in step S1 is 5.9g, while the rest is the same as in Example 1.

[0065] Comparative Example 9;

[0066] The difference from Example 1 is that the amount of modified conductive carbon powder used in step S2 is 0.8g, while the rest is the same as in Example 1.

[0067] Comparative Example 10;

[0068] The difference from Example 1 is that the amount of modified conductive carbon powder used in step S2 is 3.5g, while the rest is the same as in Example 1.

[0069] Comparative Example 11;

[0070] The difference from Example 1 is that the amount of Nafion solution used in step S3 is 0.5g, while the rest is the same as in Example 1.

[0071] Comparative Example 12;

[0072] A method for preparing an electrochemical acetylene sensor electrode differs from Example 1 in that the amount of Nafion solution used in step S3 is 2.2 g, while the rest is the same as in Example 1.

[0073] Comparative Example 13;

[0074] A method for preparing an electrochemical acetylene sensor electrode differs from Example 1 in that the amount of nano-magnesium oxide used in step S3 is 0.03 g, while the rest is the same as in Example 1.

[0075] Comparative Example 14;

[0076] A method for preparing an electrochemical acetylene sensor electrode differs from Example 1 in that the amount of nano-magnesium oxide used in step S3 is 0.11 g, while the rest is the same as in Example 1.

[0077] Comparative Example 15;

[0078] A method for preparing an electrochemical acetylene sensor electrode differs from Example 1 in that the amount of nano-barium oxide used in step S3 is 0.04 g, while the rest is the same as in Example 1.

[0079] Comparative Example 16;

[0080] A method for preparing an electrochemical acetylene sensor electrode differs from Example 1 in that the amount of nano-barium oxide used in step S3 is 0.15g, while the rest is the same as in Example 1.

[0081] Application Example 1;

[0082] An electrochemical acetylene sensor includes an ABS housing, inside which a working electrode, a reference electrode, and a counter electrode are assembled. Liquid-absorbing cotton is installed between the electrodes, and an electrolyte is filled in as a medium for charge flow. The working electrode, reference electrode, counter electrode, and test circuit board are connected to the test circuit board via corrosion-resistant metal wires and pins to achieve signal output.

[0083] The upper part of the ABS material housing includes a cover with a specific aperture. The working electrode, reference electrode and counter electrode are installed in the ABS material housing. 380μL of 4mol / L sodium chloride electrolyte is poured in. After assembling the air inlet cover, the ABS material housing is sealed. Finally, the working electrode and counter electrode are short-circuited and aged for 5 days to obtain the aged electrochemical acetylene sensor.

[0084] The working electrode, reference electrode, and counter electrode are all electrodes prepared in Example 1, namely polytetrafluoroethylene films coated with slurry, which are dried and cut into specific sizes. The working electrode and reference electrode are both Ø16mm circular pieces, and the counter electrode is an Ø16mm×6mm ring.

[0085] Application Comparative Example 1;

[0086] The difference from Application Example 1 is that the working electrode, reference electrode and counter electrode are all replaced by electrodes prepared in Comparative Example 1 instead of the electrodes prepared in Example 1. The rest are the same as Application Example 1.

[0087] Comparative Example 2;

[0088] The difference from Application Example 1 is that the working electrode, reference electrode and counter electrode are all replaced by electrodes prepared in Comparative Example 2 instead of the electrodes prepared in Example 1. The rest are the same as Application Example 1.

[0089] Application Comparative Example 3;

[0090] The difference from Application Example 1 is that the working electrode, reference electrode and counter electrode are all replaced by electrodes prepared in Comparative Example 3 instead of the electrodes prepared in Example 1. The rest are the same as Application Example 1.

[0091] Application Comparative Example 4;

[0092] The difference from Application Example 1 is that the working electrode, reference electrode and counter electrode are all replaced by electrodes prepared in Comparative Example 4 instead of the electrodes prepared in Example 1. The rest are the same as Application Example 1.

[0093] Application Comparative Example 5;

[0094] The difference from Application Example 1 is that the working electrode, reference electrode and counter electrode are all replaced by electrodes prepared in Comparative Example 5 instead of the electrodes prepared in Example 1. The rest are the same as Application Example 1.

[0095] Application Comparative Example 6;

[0096] The difference from Application Example 1 is that the working electrode, reference electrode and counter electrode are all replaced by electrodes prepared in Comparative Example 6 instead of the electrodes prepared in Example 1. The rest are the same as Application Example 1.

[0097] Application Comparative Example 7;

[0098] The difference from Application Example 1 is that the working electrode, reference electrode and counter electrode are all replaced by electrodes prepared in Comparative Example 7 instead of the electrodes prepared in Example 1. The rest are the same as Application Example 1.

[0099] Application Comparative Example 8;

[0100] The difference from Application Example 1 is that the working electrode, reference electrode and counter electrode are all replaced by electrodes prepared in Comparative Example 8 instead of the electrodes prepared in Example 1. The rest are the same as Application Example 1.

[0101] Application Comparative Example 9;

[0102] The difference from Application Example 1 is that the working electrode, reference electrode and counter electrode are all replaced by electrodes prepared in Comparative Example 9 instead of the electrodes prepared in Example 1. The rest are the same as Application Example 1.

[0103] Application Comparison Example 10;

[0104] The difference from Application Example 1 is that the working electrode, reference electrode and counter electrode are all replaced by electrodes prepared in Comparative Example 10 instead of the electrodes prepared in Example 1. The rest are the same as Application Example 1.

[0105] Application Comparative Example 11;

[0106] The difference from Application Example 1 is that the working electrode, reference electrode and counter electrode are all replaced by electrodes prepared in Comparative Example 11 instead of the electrodes prepared in Example 1. The rest are the same as Application Example 1.

[0107] Comparative Example 12;

[0108] The difference from Application Example 1 is that the working electrode, reference electrode and counter electrode are all replaced by electrodes prepared in Comparative Example 12 instead of the electrodes prepared in Example 1. The rest are the same as Application Example 1.

[0109] Application Comparative Example 13;

[0110] The difference from Application Example 1 is that the working electrode, reference electrode and counter electrode are all replaced by electrodes prepared in Comparative Example 13 instead of the electrodes prepared in Example 1. The rest are the same as Application Example 1.

[0111] Application Comparative Example 14;

[0112] The difference from Application Example 1 is that the working electrode, reference electrode and counter electrode are all replaced by electrodes prepared in Comparative Example 14 instead of the electrodes prepared in Example 1, and the rest are the same as Application Example 1.

[0113] Application Comparative Example 15;

[0114] The difference from Application Example 1 is that the working electrode, reference electrode and counter electrode are all replaced by electrodes prepared in Comparative Example 15 instead of the electrodes prepared in Example 1. The rest are the same as Application Example 1.

[0115] Application Comparative Example 16;

[0116] The difference from Application Example 1 is that the working electrode, reference electrode and counter electrode are all replaced by electrodes prepared in Comparative Example 16 instead of the electrodes prepared in Example 1. The rest are the same as Application Example 1.

[0117] Performance testing;

[0118] 1. The modified conductive carbon powder obtained in step S1 of Example 1 was subjected to electron microscopy scanning, and the results are as follows: Figure 1 As shown.

[0119] from Figure 1 It can be seen that the spherical particles of conductive carbon powder modified by the strong oxidant potassium permanganate have a relatively rough surface, and the exposed active sites serve as attachment points for gold nanoparticles, thereby achieving the dispersion of gold nanoparticles, magnesium oxide nanoparticles, and barium oxide nanoparticles. Furthermore, conductive carbon powder is often used as a medium to enhance the conductivity of electrochemical sensor electrodes, promoting charge flow and reducing sensor electrode resistance.

[0120] 2. Using the electrochemical acetylene sensors prepared in the application examples and comparative examples as test objects, a gas flow test was conducted in 40 ppm acetylene gas. The test steps are as follows:

[0121] At room temperature, after the electrochemical acetylene sensor that had completed aging was connected to a dedicated test gas cap, the output concentration of acetylene gas was controlled at 40 ppm by a mass flow meter. The test circuit board and host computer software were connected via a USB-to-RS485 serial communication cable to read data and graphs before and after gas flow, and the difference in output current signal of the test circuit board before and after gas flow was recorded. This yielded the ratio of the sensor's output current to the gas concentration, i.e., the sensitivity, which reflects the sensor's response to changes in gas concentration. The time required for the sensor's output to reach 90% of its stable value when the gas concentration undergoes a step change was calculated; this time is T90, which reflects the sensor's rapid response to gas concentration. The test results are shown in Table 1 and... Figure 2 As shown.

[0122] Table 1. Comparison of the response sensitivity of electrochemical acetylene sensors to 40 ppm acetylene gas.

[0123] Test Project Group Output signal (nA) T90(s) Application Example 1 4020 18 Application Comparative Example 1 120 48 Application Comparative Example 2 1175 61 Application Comparative Example 3 1806 55 Application Comparative Example 4 1880 35 Application Comparative Example 5 1761 42 Application Comparative Example 6 1822 38 Application Comparative Example 7 2319 36 Application Comparative Example 8 1911 45 Application Comparison Example 9 2677 29 Application Comparison Example 10 1044 55 Application Comparative Example 11 1277 46 Application Comparative Example 12 - - Application Comparative Example 13 2566 33 Application Comparative Example 14 2510 36 Application Comparative Example 15 2433 46 Application Comparative Example 16 2399 41

[0124] From the response sensitivity data in Table 1 and Figure 2The response recovery curves show that the sensor in Application Example 1 has a sensitivity of 4020 nA to 40 ppm acetylene gas and a response time of only 18 s, demonstrating excellent response characteristics. However, the electrode in Comparative Example 1 does not contain gold nanoparticles and lacks effective catalytic active components, resulting in a sensitivity of only about 120 nA to acetylene gas. The electrode in Comparative Example 2 does not contain modified conductive carbon powder, leading to large fluctuations in resistance after the sensor is assembled, making it difficult to maintain a stable working state. The electrode in Comparative Example 3 uses conventional unmodified conductive carbon, resulting in a certain degree of reduction in both the response sensitivity and response time to acetylene gas. The electrodes in Comparative Examples 4-6 use some alkaline earth metals or do not contain alkaline earth metals, and their response sensitivity to acetylene gas is close to that of Comparative Example 3, both maintaining around 1800 nA, and their response times are also relatively long.

[0125] Furthermore, the low concentration of potassium permanganate used in Comparative Example 7 resulted in insufficient active sites on the surface of the modified conductive carbon, leading to a sensitivity as low as 2319 nA. In contrast, the high concentration of potassium permanganate used in Comparative Example 8 resulted in excessive oxidation of the modified conductive carbon powder, causing some conductive carbon spheres to deform or break, which also hindered the adhesion and dispersion of the gold nanoparticles, causing the sensitivity of Comparative Example 8 to decrease to 1911 nA. In Comparative Example 9, reducing the amount of conductive carbon in the electrode also reduced the sensor's response sensitivity to acetylene gas. However, Comparative Example 10, with an increased amount of conductive carbon in the electrode slurry (3.5 g), showed a significant decrease in acetylene gas response sensitivity. This was mainly because the excessive introduction of conductive carbon reduced the content of gold nanoparticles in the electrode, leading to a decrease in the sensor's catalytic activity against acetylene gas. Comparative Example 11 showed a response of only 1277 nA to acetylene gas, indicating that the reduced amount of Nafion solution resulted in poor powder wetting in the mixed slurry and hindered ion transport. However, the slurry in Application Comparative Example 12, which used excessive Nafion solution, underwent denaturation, and its viscosity became insufficient for coating, resulting in Application Comparative Example 12 failing to be properly assembled into a sensor.

[0126] Furthermore, in comparative examples 13-16, when the amount of nano-magnesium oxide or nano-barium oxide added was reduced or increased, the response sensitivity to acetylene gas was reduced to a certain extent, and the response time T90 was extended to more than 30 seconds.

[0127] 3. Using the electrochemical acetylene sensors prepared in the application examples and comparative examples as test objects, cross-response tests were conducted in gases of different concentrations. The test steps are as follows:

[0128] At room temperature, after the electrochemical acetylene sensor has completed its aging process, it is connected to a dedicated test gas cap, and the gas concentration is controlled by a mass flow meter. The test circuit board and the host computer software are connected via a USB to RS485 serial communication cable to read the data and graphs before and after gas flow, and record the difference in the output current signal of the test circuit board before and after gas flow, thereby obtaining the sensor's sensitivity performance in different cross-gases.

[0129] The cross gases tested by the electrochemical acetylene sensor in this application are: 100 ppm hydrogen sulfide, 10 ppm sulfur dioxide, 100 ppm nitric oxide, 10 ppm formaldehyde, 500 ppm carbon monoxide, 100 ppm ethylene, and 500 ppm ethanol.

[0130] The test results are shown in Table 2 and Figures 3 to 4 As shown.

[0131] Table 2. Cross-response test comparison table for electrochemical acetylene sensors

[0132]

[0133] Table 2 shows that the cross-response of Application Example 1 to 100 ppm hydrogen sulfide is equivalent to 1.2 ppm acetylene. Application Example 1, without the catalytic component gold nanoparticles, shows almost no response to hydrogen sulfide. Application Example 2, without modified conductive carbon, and Application Example 3, with conventional conductive carbon, show increased cross-response to 5.6 ppm and 8.2 ppm respectively. Application Example 4, whose slurry does not contain alkaline earth metals, shows a cross-response to 128.2 ppm acetylene to 100 ppm hydrogen sulfide. Similarly, Application Example 6, without nano-magnesium oxide, shows a cross-response to 122.1 ppm acetylene to 100 ppm hydrogen sulfide, while Application Example 5, with nano-magnesium oxide, shows a cross-response to 12.7 ppm acetylene to 100 ppm hydrogen sulfide. Furthermore, Application Example 13, with reduced nano-magnesium oxide content, shows a cross-response to 62.8 ppm acetylene to 100 ppm hydrogen sulfide, a very high cross-response coefficient. In contrast, the cross-response of acetylene to 18.8 ppm was reduced to 100 ppm hydrogen sulfide in the application comparison ratio 14, which still remained at a slightly high value.

[0134] Similar results were observed in the 10 ppm sulfur dioxide ventilation test. Application Example 1 showed a response to 10 ppm sulfur dioxide equivalent to 1.1 ppm acetylene, while Application Comparative Example 1, without the addition of the catalytic component, nano-gold particles, showed almost no response to sulfur dioxide. Application Comparative Examples 4 and 5, without the addition of nano-barium oxide in the slurry, showed cross-responses to 10 ppm sulfur dioxide equivalent to 36.2 and 19.7 ppm acetylene, respectively. Application Comparative Example 15, with a small amount of nano-barium oxide added to the slurry, showed a cross-response to 8.9 ppm acetylene for 10 ppm sulfur dioxide, indicating that a low addition amount was insufficient to suppress the cross-response signal of acidic sulfur dioxide gas. However, Application Comparative Example 16, with the addition of nano-barium oxide increased to 0.15 g, showed a cross-response to 12.8 ppm acetylene, mainly because excessive nano-barium oxide readily reacts with CO32-. 2- or SO4 2- This combination leads to a severe decrease in anti-interference capability.

[0135] In applications such as coal mines and chemical industries, hydrogen sulfide and sulfur dioxide are common byproducts of acetylene gas. Sensitive detection of acetylene and differentiation between hydrogen sulfide and sulfur dioxide signals are crucial for efficient and accurate acetylene detection. Therefore, adding alkaline earth metal nano-magnesium oxide and barium oxide to the electrode slurry of electrochemical sensors offers significant performance advantages in enhancing the resistance to cross-interference from hydrogen sulfide and sulfur dioxide in electrochemical acetylene sensors.

[0136] Under the ventilation test of 500ppm carbon monoxide, 10ppm formaldehyde, 100ppm nitric oxide, 100ppm ethylene and 500ppm ethanol, Application Example 1 showed a low cross-response, demonstrating excellent anti-cross-interference ability. Application Comparative Example 1, which does not contain catalytic gold nanoparticles, showed almost no response to the above gases. Application Comparative Examples 2 to 6 did not show significant differences in the cross-response to the above gases.

[0137] In addition, by Figure 3 The application of Example 1 in stepwise ventilation and linear fitting curves in 0-100 ppm acetylene gas shows that Example 1 maintains a short response and recovery time for acetylene gas within the 0-100 ppm concentration range as the acetylene gas concentration increases, demonstrating excellent response and recovery characteristics. Even at concentrations as low as 20 ppm, a current signal of 2000 nA is still output. Furthermore, from... Figure 3 The illustration shows a linear fit curve between the acetylene gas concentration (x) and the output sensitivity value (y): y = 98.036x + 160.05, R0 2 =0.9993 (where R 2 R1 is the linear fit coefficient, a statistic that measures how well a linear regression model fits the data.2 = Sum of squares of regression / Total sum of squares, R 2 The value ranges from 0 to 1; the closer the value is to 1, the better the model fits the data. This indicates that the acetylene sensor has an extremely low detection limit and excellent linearity within its measurement range.

[0138] Figure 4 To apply the cyclic adsorption-desorption curve of Example 1 in 40 ppm acetylene gas, from Figure 4 It can be seen that the sensor exhibits excellent response sensitivity to acetylene gas in each test cycle, and the response and desorption performance remain stable with excellent consistency.

[0139] The embodiments described in this specific implementation are preferred embodiments of this application and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. An electrochemical acetylene sensor electrode, comprising a polytetrafluoroethylene (PTFE) membrane and a paste coated on the PTFE membrane, characterized in that, The slurry comprises nano-gold particles, nano-magnesium oxide, nano-barium oxide, modified conductive carbon powder, and Nafion solution in a weight ratio of (0.47-0.50):(0.02-0.20):(0.02-0.18):(1-3):(0.6-2.0); the modified conductive carbon powder is obtained by ball milling potassium permanganate, deionized water, and conductive carbon.

2. The electrochemical acetylene sensor electrode according to claim 1, characterized in that, The weight ratio of potassium permanganate, deionized water and conductive carbon is (0.2-0.4):(6-12):

1.

3. The electrochemical acetylene sensor electrode according to claim 2, characterized in that, The conductive carbon powder has a particle size range of 1-3 μm and a spherical or near-spherical morphology.

4. The electrochemical acetylene sensor electrode according to claim 1, characterized in that, The nano-magnesium oxide and nano-barium oxide are spherical or near-spherical particles with a particle size in the range of 50-200 nm.

5. A method for preparing an electrochemical acetylene sensor electrode according to any one of claims 1-4, characterized in that, Includes the following steps: S1. After ultrasonically mixing potassium permanganate, deionized water and conductive carbon, the mixture is ground at a speed of 80-150 r / min for 4-6 h to obtain a ground solution. The ground solution is centrifuged, the lower precipitate is collected and washed with deionized water to obtain a solid. The solid is dried at a temperature of 60-80℃ for 4-8 h and passed through a 200-mesh sieve to obtain modified conductive carbon powder. S2. Dissolve chloroauric acid in deionized water, add modified conductive carbon powder and mix ultrasonically. Add oxalic acid solution under stirring conditions in a water bath at 60-80℃ to carry out the reaction. After the reaction is completed, discard the supernatant to obtain a mixture of gold nanoparticles and modified conductive carbon powder. S3. The mixture of nano-gold particles and modified conductive carbon powder, nano-magnesium oxide, nano-barium oxide and Nafion solution are ultrasonically mixed, and then ground at a speed of 50-200 r / min for 0.3-1.0 h to obtain a slurry; S4. Coat the slurry onto a polytetrafluoroethylene membrane and dry it at 100-120℃ for 1-3 hours to obtain an electrochemical acetylene sensor electrode.

6. The method for preparing an electrochemical acetylene sensor electrode according to claim 5, characterized in that, In step S1, the centrifugation speed is 6000-8000 r / min, and the centrifugation time is 5-8 min.

7. The method for preparing an electrochemical acetylene sensor electrode according to claim 5, characterized in that, In step S2, the weight ratio of chloroauric acid, deionized water, modified conductive carbon powder, and oxalic acid solution is 1:(30-50):(1-3):(45-60).

8. The method for preparing an electrochemical acetylene sensor electrode according to claim 5, characterized in that, In step S2, the stirring speed in the water bath is 600-800 r / min, and the reaction time in the water bath is 30-40 min.

9. The method for preparing an electrochemical acetylene sensor electrode according to claim 5, characterized in that, In step S2, the molar concentration of the oxalic acid solution is 0.2-0.3 mol / L.

10. An electrochemical acetylene sensor, characterized in that, Includes the electrochemical acetylene sensor electrode as described in any one of claims 1-4.

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