Electrochemical oxygen sensor

Abstract

The utility model discloses an electrochemical oxygen sensor which comprises a working electrode, a reference electrode, a counter electrode and an electrolyte adsorption film, and the working electrode, the reference electrode and the counter electrode are sequentially arranged and are integrated into a whole through the electrolyte adsorption film; the working electrode comprises a first gas-permeable membrane and a printing part printed on the first gas-permeable membrane, and the printing part comprises a catalyst and an adhesive. According to the electrochemical oxygen sensor disclosed by the utility model, the electrode catalyst layer is printed on the gas-permeable membrane to form the gas-permeable membrane working electrode, so that the structure of the electrochemical oxygen sensor is simplified, and the electrochemical oxygen sensor is simple in overall structure, lower in cost, shorter in response time and higher in sensitivity.

Description

Technical Field

[0001] This utility model relates to the field of electrochemical technology, and in particular to an electrochemical oxygen sensor. Background Technology

[0002] In practical production activities, oxygen concentration monitoring is of great significance. For example, in confined space operations, oxygen consumption leads to a decrease in oxygen concentration, potentially causing asphyxiation or poisoning. By monitoring oxygen concentration, low-oxygen environments can be detected promptly, allowing for corresponding measures such as ventilation and oxygen supply to ensure the safety of workers. Similarly, in industries such as steel smelting and glass manufacturing, combustion and oxidation processes have a significant impact on product quality. By monitoring oxygen concentration, the progress of combustion and oxidation reactions can be precisely controlled, ensuring stable product quality. Furthermore, in the medical field, oxygen concentration monitoring is even more crucial for respiratory therapy. By monitoring oxygen concentration, it ensures that patients receive the correct oxygen concentration, avoiding complications caused by excessively high or low oxygen levels.

[0003] Oxygen permeability refers to the volume of oxygen passing through a unit area of ​​materials such as plastic film, aluminum foil, or vacuum-metallized film per unit time under constant temperature and unit pressure difference, during stable permeation. Among various oxygen detection methods, electrochemical sensors are favored due to their high sensitivity, ease of operation, and fast response. (See attached image) Figure 1 As shown, the oxygen-permeable membrane O 2 Electrochemical sensors generally consist of a working electrode, a reference electrode, and a counter electrode. Their basic principle for monitoring oxygen changes is O2. 2 The change in electrochemical signal caused by the redox reaction at the electrode surface. Due to the nonlinearity of the current in the oxygen electrochemical reaction, in O... 2 Electrochemical sensors all require methods to control the oxygen diffusion rate. Currently, the most common method for controlling the diffusion rate to achieve full-range (0%-100%) oxygen concentration detection is the use of oxygen-permeable membrane structures. However, the use of oxygen-permeable membrane structures often requires diffusion barriers, elastic rings, double-sided adhesive, and other components, thus complicating the sensor structure and increasing its cost. Furthermore, the oxygen-permeable membrane's overly stringent limitation on the oxygen diffusion rate prolongs the sensor's response time and, to some extent, reduces its sensitivity. Utility Model Content

[0004] The main technical problem solved by this utility model is to provide an electrochemical oxygen sensor with a simple structure, shorter response time, and higher sensitivity, avoiding all or some of the above-mentioned defects.

[0005] To solve the above technical problems, one of the technical solutions adopted by the utility model is to provide an electrochemical oxygen sensor, which comprises a working electrode, a reference electrode, a counter electrode and an electrolyte adsorption film, the working electrode, the reference electrode and the counter electrode are sequentially arranged and integrated into one through the electrolyte adsorption film;

[0006] The working electrode comprises a first gas-permeable film and a printed part printed on the first gas-permeable film, and the printed part comprises a catalyst and a binder.

[0007] The catalyst comprises platinum black catalyst and carbon catalyst.

[0008] The printed part further comprises an organic solvent.

[0009] The electrochemical oxygen sensor is provided with an air inlet and an air outlet, and the air inlet is opposite to the working electrode.

[0010] The electrochemical oxygen sensor further comprises a second gas-permeable film, which covers the air inlet.

[0011] The electrochemical oxygen sensor further comprises a third gas-permeable film, which covers the second gas-permeable film.

[0012] The materials and oxygen permeation amounts of the first gas-permeable film, the second gas-permeable film and the third gas-permeable film are the same.

[0013] The materials of the first gas-permeable film, the second gas-permeable film and the third gas-permeable film are any one of PTFE, PVDF, PP and PC.

[0014] The oxygen permeation amounts of the first gas-permeable film, the second gas-permeable film and the third gas-permeable film are any value between 2400 cm 3 / (m 2 *24h*0.1MPa) and 3000 cm 3 / (m 2 *24h*0.1MPa).

[0015] The electrochemical oxygen sensor further comprises a signal connector, which is adjacent to the counter electrode.

[0016] Compared with the prior art, the electrochemical oxygen sensor has the following beneficial effects: the electrode catalyst layer is printed on the gas-permeable film to form a gas-permeable film working electrode, which simplifies the structure of the electrochemical oxygen sensor, has a simple overall structure, is low in cost, has a shorter response time and higher sensitivity. BRIEF DESCRIPTION OF DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the description of the embodiments will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and all other drawings obtained by those skilled in the art without creative labor based on the embodiments of the present application shall fall within the scope of protection of the present application.

[0018] Figure 1 is the commonly used oxygen permeable film O 2 The structural diagram of the electrochemical sensor;

[0019] Figure 2 is the structural diagram of the electrochemical oxygen sensor of the present application;

[0020] Figure 3 is the electrochemical oxygen sensor of the present application and the commonly used oxygen permeable film O 2 Comparison of oxygen detection data of the electrochemical sensor;

[0021] Figure 4 is the electrochemical oxygen sensor of the present application and the commonly used oxygen permeable film O 2 Comparison chart of oxygen detection sensitivity of the electrochemical sensor;

[0022] Figure 5 is the electrochemical oxygen sensor of the present application and the commonly used oxygen permeable film O 2 Comparison chart of background current linear fitting of the electrochemical sensor. DETAILED DESCRIPTION

[0023] The technical solutions in the embodiments of the present application will be described clearly and completely in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only some embodiments of the present application, not all the embodiments. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative labor shall fall within the scope of protection of the present application.

[0024] The directional indications (such as up, down, left, right, front, back, and the like) in the embodiments of the present application are only used to explain the relative positional relationship and movement condition between components in a certain specific posture (as shown in the drawings), and if the specific posture changes, the directional indications also change accordingly. The terms "first", "second", and the like in the present application are used to distinguish different objects, rather than to describe a specific order. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not limited to the listed steps or units, but can optionally include steps or units not listed, or can optionally include other steps or units inherent to the process, method, product, or device.

[0025] Reference herein to "embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the application. The appearance of the phrase in various places in the specification does not necessarily all refer to the same embodiment, nor does it necessarily exclude other embodiments from being claimed. It is explicitly and implicitly understood that the embodiments described herein can be combined with other embodiments.

[0026] Please refer to Figures 1 to 5 , Figure 2 is a structural schematic diagram of the electrochemical oxygen sensor, the electrochemical oxygen sensor comprises a working electrode 1, a reference electrode 2, a counter electrode 3 and an electrolyte adsorption film 4, the working electrode 1, the reference electrode 2 and the counter electrode 3 are arranged in sequence and integrated into one body through the electrolyte adsorption film 4. The electrochemical signal change caused by the oxidation-reduction reaction of oxygen on the surface of the working electrode 1, the reference electrode 2 and the counter electrode 3, so as to monitor the change of oxygen. The traditional way is to cover the oxygen-permeable film structure 10 on the electrode, so as to control the oxygen diffusion rate, as shown in Figure 1 In order to simplify the structure, the present application cancels the commonly used oxygen-permeable film structure 10 at present, prints the electrode catalytic layer on the gas-permeable film, so as to form the working electrode which can permeate oxygen, and replaces the original working electrode. Specifically, the working electrode 1 in the present application comprises a first gas-permeable film and a printed part printed on the first gas-permeable film, and the printed part comprises a catalyst and a binder. In the first embodiment of the present application, the catalyst in the printed part contains an electrode catalyst, and the first gas-permeable film selects a normal gas-permeable film, and the oxygen permeation rate of the normal gas-permeable film is equivalent to that of the general oxygen-permeable film commonly used at present. The above normal gas-permeable film specifically refers to that the oxygen permeation amount is limited to 1000 cm 3 / (m 2 *24h*0.1MPa) to 1800 cm 3 / (m 2The preferred oxygen permeable membrane has an oxygen permeation rate of 1200cm 3 / (m 2 *24h*0.1MPa) of the oxygen permeable membrane. By the above arrangement, the electrode catalyst and the adhesive are printed on the first oxygen permeable membrane to form a new working electrode, which not only plays the role of the original electrode, but also replaces the original oxygen permeable membrane structure, so that the electrochemical oxygen sensor can measure the full range of oxygen (0%-100%) without the need for an oxygen permeable membrane. The complex structure of the oxygen permeable membrane is not needed to control the oxygen rate, which makes the overall structure of the sensor simpler, reduces the cost, has a shorter response time, and has a higher sensitivity.

[0027] The catalyst in the present application includes platinum black catalyst and carbon catalyst, and the printed part has an electrode effect. The platinum black catalyst, carbon catalyst, and adhesive have a mass ratio of 3:3:1 to 1:5:1, and preferably a mass ratio of 3:3:1, so that the printed layer has a better effect.

[0028] The printed part in the present application also includes an organic solvent, which includes but is not limited to dimethyl sulfoxide, acetone, tetrahydrofuran, and cyclopentane. The organic solvent is an organic compound widely used in life and production, and exists in paints, adhesives, varnishes, and cleaning agents. The mass ratio of the organic solvent in the printed part is 5-12, and preferably 10.

[0029] The electrochemical oxygen sensor in the present application is provided with an air inlet 5 and an air outlet. The air inlet 5 is opposite to the working electrode 1, and the air inlet 5 and the air outlet are used to make the gas pass through the sensor to monitor the change of oxygen.

[0030] In the second embodiment of the present application, the electrochemical oxygen sensor further includes a second oxygen permeable membrane 6, which covers the air inlet 5. The diameter of the second oxygen permeable membrane 6 is any value of 0.8-1 times the diameter of the chamber of the electrochemical oxygen sensor, and preferably 1 times the diameter of the chamber of the electrochemical oxygen sensor. The difference between the first embodiment and the second embodiment is that in the second embodiment, the first oxygen permeable membrane and the second oxygen permeable membrane 6 are selected to be a membrane with a low oxygen permeation rate. In the present application, the membrane with a low oxygen permeation rate specifically refers to an oxygen permeable membrane with an oxygen permeation rate of 2400cm 3 / (m 2 *24h*0.1MPa) to 3000cm 3 / (m 2 *24h*0.1MPa). After the second oxygen permeable membrane 6 is stacked on the working electrode 1 formed by the first oxygen permeable membrane, the oxygen permeation rate of the two layers of low oxygen permeable membranes is measured by a gas permeation instrument to be 1600cm 3 / (m 2around 1000cm3 / (m2*24h*0.1MPa), the oxygen permeation amount is in the range of 1000cm3 / (m2*24h*0.1MPa) to 1800cm3 / (m2*24h*0.1MPa), which meets the requirements of normal use. 3 2 around 1000cm3 / (m2*24h*0.1MPa), the oxygen permeation amount is in the range of 1000cm3 / (m2*24h*0.1MPa) to 1800cm3 / (m2*24h*0.1MPa), which meets the requirements of normal use. 3 2 around 1000cm3 / (m2*24h*0.1MPa), the oxygen permeation amount is in the range of 1000cm3 / (m2*24h*0.1MPa) to 1800cm3 / (m2*24h*0.1MPa), which meets the requirements of normal use. Figure 1 The performance of the electrochemical oxygen sensor of the present application is compared with that of the electrochemical oxygen sensor commonly used at present in the data in the Figure 3 The response time of the electrochemical oxygen sensor of the present application is shorter and the sensitivity is higher than those of the electrochemical oxygen sensor commonly used at present.

[0031] By controlling the number of layers and the diameter of the gas-permeable membrane to control the rate of oxygen diffusion to the electrode catalytic layer, the electrochemical oxygen sensor can measure the full range (0%-100%) of oxygen without the need for an oxygen-permeable membrane. The need for the complex structure of the oxygen-permeable membrane to control the oxygen rate makes the overall structure of the sensor simpler, reduces the cost, and at the same time, within the linear range of the oxygen electrochemical reaction current, improves the oxygen diffusion rate, to a certain extent, shortens the response time and improves the sensitivity.

[0032] In the third embodiment of the present application, the electrochemical oxygen sensor further comprises a third gas-permeable membrane, which covers the second gas-permeable membrane 6. Compared with the second embodiment, the sensor adds a third gas-permeable membrane, and the first gas-permeable membrane, the second gas-permeable membrane 6 and the third gas-permeable membrane in the third embodiment all use a membrane with a low gas permeation amount. The diameter of the third gas-permeable membrane 5 is also any value between 0.8 and 1 times the diameter of the chamber of the electrochemical oxygen sensor, and the preferred diameter value is 1 times the diameter of the chamber of the electrochemical oxygen sensor. After the third gas-permeable membrane is continuously stacked on the structure of the second embodiment, the oxygen permeation amount of the above-mentioned three layers of low gas permeation amount membranes is about 1400cm3 / (m2*24h*0.1MPa) measured by a gas permeation instrument, which is in the range of 1000cm3 / (m2*24h*0.1MPa) to 1800cm3 / (m2*24h*0.1MPa), which meets the requirements of normal use. 3 2 around 1000cm3 / (m2*24h*0.1MPa), the oxygen permeation amount is in the range of 1000cm3 / (m2*24h*0.1MPa) to 1800cm3 / (m2*24h*0.1MPa), which meets the requirements of normal use. 3 2 around 1000cm3 / (m2*24h*0.1MPa), the oxygen permeation amount is in the range of 1000cm3 / (m2*24h*0.1MPa) to 1800cm3 / (m2*24h*0.1MPa), which meets the requirements of normal use. 3 2 around 1000cm3 / (m2*24h*0.1MPa), the oxygen permeation amount is in the range of 1000cm3 / (m2*24h*0.1MPa) to 1800cm3 / (m2*24h*0.1MPa), which meets the requirements of normal use.

[0033] The materials and oxygen permeation amounts of the first gas-permeable membrane, the second gas-permeable membrane 6 and the third gas-permeable membrane in the present application are the same.

[0034] The materials of the first gas-permeable membrane, the second gas-permeable membrane 6 and the third gas-permeable membrane in the present application are any one of PTFE, PVDF, PP and PC.

[0035] ​​​​​The oxygen permeation of the first, second and third gas permeable membrane in the present application is 2400 cm 3 / (m 2 *24h*0.1MPa) to 3000 cm 3 / (m 2 *24h*0.1MPa). Preferably, the gas permeable membrane in the present embodiment has an oxygen permeation of 2400 cm 3 / (m 2 *24h*0.1MPa).

[0036] The electrochemical oxygen sensor in the present application further comprises a signal connector 7 adjacent to the counter electrode 3 and electrically connected to the external components.

[0037] The principle of preparing the electrochemical oxygen sensor in the present application is to print the catalyst and the binder on the working electrode using the low gas permeable membrane, and to cover the working electrode with 1-2 layers of low gas permeable membrane. The oxygen permeation of the two layers of low gas permeable membrane is about 1600 cm 3 / (m 2 *24h*0.1MPa), and the oxygen permeation of the three layers of low gas permeable membrane is about 1400 cm 3 / (m 2 *24h*0.1MPa), which is comparable to the oxygen permeation of the general oxygen permeable membrane (1000 cm 3 / (m 2 *24h*0.1MPa) -1800 cm 3 / (m 2 *24h*0.1MPa).

[0038] In addition, it is calculated that, taking the sensor chamber with a height of 30 mm and a diameter of 25 mm as an example, and in the case that the diameter of the bottom gas outlet hole is 6 mm, the oxygen concentration in the chamber can be maintained at about 25% by continuously and uninterruptedly supplying pure oxygen from air using the two layers of low gas permeable membrane, i.e. maintained in the linear range of the oxygen electrochemical reaction current (0-30%). Based on the above two points, it is completely feasible to use multiple layers of low gas permeable membrane to replace the oxygen permeable membrane to control the oxygen diffusion rate of the sensor.

[0039] In actual preparation, the method for preparing the electrochemical oxygen sensor is as follows:

[0040] 1. First, weigh the platinum black catalyst: carbon catalyst: binder in a mass ratio range of 3:3:1 to 1:5:1 (preferably a mass ratio of 3:3:1), and add an organic solvent in a mass ratio range of 5-12 (preferably a mass ratio of 10). The organic solvent includes but is not limited to dimethyl sulfoxide, acetone, tetrahydrofuran, cyclopentane.

[0041] 2. The mixed slurry is then placed in a stirring device, which is set to rotate at 1000 rpm (range 600-1200 rpm, preferably 1000 rpm) for 240 min (range 180-360 min, preferably 240 min). The stirring device includes, but is not limited to, a magnetic stirrer, an overhead stirrer, a ball mill.

[0042] 3. The above slurry is printed onto a pre-set low permeability membrane, which is dried at a temperature of 60°C (range 50-70°C, preferably 60°C) for 240 min (range 180-360 min, preferably 240 min) to obtain a low permeability membrane working electrode. The printing method includes, but is not limited to, screen printing or spray gun printing.

[0043] 4. The low permeability membrane working electrode is placed at the gas inlet of the sensor, and 1-2 layers (preferably 1 layer) of low permeability membrane with a diameter of 1 times (range 0.8-1, preferably 1) the diameter of the chamber are added thereon.

[0044] The test method of the electrochemical oxygen sensor of the present application and the commonly used oxygen-permeable membrane type O 2 The electrochemical sensor is used for performance comparison, and the specific test method is as follows:

[0045] 1. The performance of the sensor is tested by a self-made tool. The closed test box has a length, width and height of 200*150*150 mm, and each side has an air inlet and an air outlet. The side has an opening connected to the lead wire of the electrochemical workstation. The test process is as follows: first, a certain flow of compressed air (oxygen concentration 20.9%) is introduced into the closed test box, and the background current is read after 300 s. Then, 60% oxygen standard gas, nitrogen (oxygen concentration 0%), and 100% pure oxygen are introduced in turn, and the air inlet time is 300 s. In the electrochemical test, the commonly used oxygen-permeable membrane type oxygen electrochemical sensor and the electrochemical oxygen sensor of the present application are both three-electrode systems, which are divided into working electrode (WE), reference electrode (RE) and counter electrode (CE). The test method is constant potential polarization, the polarization potential is-0.6 V, and the sampling interval is 1 s.

[0046] 2. The test results of the commonly used oxygen-permeable membrane type oxygen electrochemical sensor are shown in Table 1. Figure 3 As shown in Table 1, the sensitivity of the commonly used oxygen-permeable membrane type oxygen electrochemical sensor is 2.7 μA / %vol.O2, the linearity is 0.9989, the background current in air is-67 μA, and the T 90 9S.

[0047] 3. According to the calculation, the sensitivity of the electrochemical oxygen sensor of the present application is 3.4395 μA / %vol.O2, the linearity is 0.9995, the background current in air is-80.7 μA, and the T90 For 6S, see the specific performance comparison of the commonly used oxygen-permeable membrane type oxygen electrochemical sensor in Figure 3 The comparison detection result shows that the working electrode prepared by printing the low gas permeation membrane can realize full-range detection of oxygen without the oxygen-permeable membrane, and is superior to the oxygen electrochemical sensor based on the oxygen-permeable membrane structure in sensitivity and response time due to higher oxygen diffusion rate.

[0048] The electrochemical oxygen sensor of the utility model is used, the electrode catalytic layer is printed on the gas-permeable membrane to form a gas-permeable membrane working electrode, the structure of the electrochemical oxygen sensor is simplified, the overall structure is simple, the cost is lower, the response time is shorter, and the sensitivity is higher.

[0049] The above is only the embodiment of the utility model, and does not limit the patent range of the utility model, and any equivalent structure or equivalent process transformation using the contents of the utility model specification and drawings, or direct or indirect application in other related technical fields, are also included in the patent protection range of the utility model.

Claims

1. An electrochemical oxygen sensor, characterized by The electrochemical oxygen sensor comprises a working electrode, a reference electrode, a counter electrode and an electrolyte adsorption film, the working electrode, the reference electrode and the counter electrode are arranged in sequence and integrated by the electrolyte adsorption film; The working electrode comprises a first gas-permeable film and a printed part printed on the first gas-permeable film, and the printed part comprises a catalyst and a binder.

2. The electrochemical oxygen sensor of claim 1, wherein, The catalyst comprises platinum black catalyst and carbon catalyst.

3. The electrochemical oxygen sensor of claim 2, wherein, The printed part further comprises an organic solvent.

4. The electrochemical oxygen sensor of claim 1, wherein, The electrochemical oxygen sensor is provided with an air inlet and an air outlet, and the air inlet is opposite to the working electrode.

5. The electrochemical oxygen sensor of claim 4, wherein, The electrochemical oxygen sensor further comprises a second gas-permeable film, which covers the air inlet.

6. The electrochemical oxygen sensor of claim 5, wherein, The electrochemical oxygen sensor further comprises a third gas-permeable film, which covers the second gas-permeable film.

7. The electrochemical oxygen sensor of claim 6, wherein, The materials and oxygen permeation amounts of the first gas-permeable film, the second gas-permeable film and the third gas-permeable film are the same.

8. The electrochemical oxygen sensor of claim 7, wherein, The materials of the first gas-permeable film, the second gas-permeable film and the third gas-permeable film are any one of PTFE, PVDF, PP and PC.

9. The electrochemical oxygen sensor of claim 7, wherein, The oxygen transmission rate of the first breathable film, the second breathable film, and the third breathable film are each any value between 2400 cm 3 / (m 2 *24h*0.1 MPa) and 3000 cm 3 / (m 2 *24h*0.1 MPa).

10. The electrochemical oxygen sensor according to any one of claims 1 to 9, characterized in that The electrochemical oxygen sensor further comprises a signal connector, which is adjacent to the counter electrode.

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