Full-scale lead-free oxygen sensor

Abstract

A full-scale lead-free oxygen sensor comprises a shell, an electrolyte arranged in the shell, a tin anode and a catalytic electrode which are immersed in the electrolyte, and an electrolyte adsorption film is arranged between the tin anode and the catalytic electrode. The electrolyte comprises caustic alkali, carbonate, bicarbonate and thiosulfate. Due to the adoption of the alkaline electrolyte, the hydrogen evolution competitive reaction of the lead-free oxygen sensor is avoided, so that the oxygen concentration measurement accuracy of the lead-free oxygen sensor is improved.

Description

Technical Field

[0001] This invention relates to the field of oxygen sensor technology, specifically to a lead-free oxygen sensor, and more specifically to a full-range lead-free oxygen sensor. Background Technology

[0002] Electrochemical oxygen sensors are inexpensive, simple, and can operate at room temperature. They are also widely used in a wide range of fields, such as checking for oxygen deficiency in ship cabins and inspection holes, and detecting oxygen concentration in medical equipment such as anesthesia machines and ventilators, thanks to their high accuracy, stable performance, simple operation, and economy.

[0003] One existing type of electrochemical oxygen sensor is the lead-oxygen sensor, which mainly includes two electrodes, namely a Pt-C working electrode and a lead wire pressing block counter electrode. The two electrodes are placed in a container containing an electrolyte in which the two electrodes are placed. The electrolyte is usually an alkaline electrolyte.

[0004] Existing electrochemical oxygen sensors convert chemical energy into electrical energy in an electrolyte based on the principle of a lead-oxygen galvanic cell. However, these sensors use lead, a highly toxic heavy metal that is extremely harmful to human health. At the beginning of this century, the European RoHS directive restricted the use of lead in electronic and electrical equipment, and my country's "Regulations on the Management of Pollution Control of Electronic Information Products" also made corresponding provisions. Therefore, the development of lead-free oxygen sensors is imperative.

[0005] Later, the industry also adopted lead-free oxygen sensors. Although this type of sensor solved the problems of environmental pollution and harm to the human body, it uses an acidic electrolyte. According to the chemical reactivity series of metals, this type of lead-free oxygen sensor using an acidic electrolyte is prone to hydrogen evolution competitive reaction, which causes the lead-free oxygen sensor to still output an electrical signal under oxygen-free conditions. This seriously affects the accuracy of the lead-free oxygen sensor in measuring oxygen concentration.

[0006] Therefore, the industry needs to provide an improved lead-free oxygen sensor to overcome the shortcomings of the prior art. Summary of the Invention

[0007] The purpose of this invention is to solve the above-mentioned problems and provide a full-range lead-free oxygen sensor.

[0008] To achieve the objectives of this invention, the following technical solution is adopted: A full-range lead-free oxygen sensor includes: a housing, an electrolyte disposed within the housing, a tin anode and a catalytic electrode immersed in the electrolyte, wherein an electrolyte adsorption membrane is disposed between the tin anode and the catalytic electrode. The electrolyte includes caustic alkali, carbonate, bicarbonate and thiosulfate.

[0009] Preferably, the electrolyte comprises cesium carbonate, cesium bicarbonate, and sodium thiosulfate, with a molar concentration ratio between the three being between 1:0.1:0.003 and 1:0.1:0.05.

[0010] Preferably, the electrolyte comprises cesium carbonate, cesium bicarbonate, and sodium thiosulfate, with a molar concentration ratio of 1:0.1:0.003.

[0011] More preferably, the electrolyte comprises cesium carbonate, cesium bicarbonate, and sodium thiosulfate, with a molar concentration ratio of 1:0.1:0.01.

[0012] More preferably, the electrolyte comprises cesium carbonate, cesium bicarbonate, and sodium thiosulfate, with a molar concentration ratio of 1:0.1:0.05.

[0013] Preferably, an oxygen-permeable membrane is provided on the housing at the position corresponding to the catalytic electrode.

[0014] Preferably, an anode pin is provided on the side of the housing, and the tin anode is electrically connected to the anode pin via an anode wire; a cathode pin is also provided on the side of the housing, and the catalytic electrode is electrically connected to the cathode pin via a cathode wire. Preferably, the oxygen-permeable membrane is a PTFE membrane.

[0015] Preferably, the catalytic electrode is made of any one of carbon, platinum, gold, silver, and copper, or an alloy formed by any two or more of these materials.

[0016] More preferably, the anode wire and / or cathode wire are made of one of the following metallic materials: gold, silver, copper, or nickel, or an alloy material formed by combining any two or more materials.

[0017] Compared with the prior art, the beneficial technical effects of the present invention are as follows: In the full-range lead-free oxygen sensor provided by this invention, an alkaline electrolyte is used, specifically an electrolyte containing cesium carbonate, cesium bicarbonate, and sodium thiosulfate, and the three components have an appropriate molar ratio. This avoids the risk of reduced accuracy of oxygen concentration measurement caused by the use of acidic electrolytes in the prior art.

[0018] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and will become apparent from the description or may be learned by practice of the invention. Attached Figure Description

[0019] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein: Figure 1 This is a schematic structural diagram of the full-range lead-free oxygen sensor of the present invention.

[0020] Figure 2 The response curve of the output electrical signal of the full-range lead-free oxygen sensor prepared according to the first embodiment of the present invention as a function of oxygen concentration.

[0021] Figure 3 Linear graphs of oxygen concentration versus voltage for full-range lead-free oxygen sensors prepared according to the first, second, and third embodiments of the present invention.

[0022] Figure 4 A linear relationship between oxygen concentration and voltage for oxygen sensors prepared according to various embodiments of the present invention. Detailed Implementation

[0023] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention and should not be construed as limiting the present invention.

[0024] Those skilled in the art will understand that, unless specifically stated otherwise, the singular forms “a,” “an,” “the,” and “the” used herein may also include the plural forms. It should be further understood that the term “comprising” as used in this specification means the presence of the stated features, integers, steps, operations, elements, and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, and / or components, nor does it exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. It should be understood that when we say an element is “connected” or “coupled” to another element, it can be directly connected or coupled to the other element, or there may be intermediate elements. Furthermore, “connected” or “coupled” as used herein can include wireless connection or wireless coupling. The term “and / or” as used herein includes all or any unit and all combinations of one or more associated listed items.

[0025] It will be understood by those skilled in the art that, unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. It should also be understood that terms such as those defined in general dictionaries should be understood to have the same meaning as in the context of the prior art, and should not be interpreted in an idealized or overly formal sense unless specifically defined as herein.

[0026] In one embodiment of the present invention, reference is made to... Figure 1-3 A full-range lead-free oxygen sensor 100 is provided, comprising: a housing 10, an electrolyte 20 placed inside the housing 10, a tin anode 30 immersed in the electrolyte 20, and a catalytic electrode 40, wherein an electrolyte adsorption membrane 50 is disposed between the tin anode 30 and the catalytic electrode 40.

[0027] Here, the electrolyte 20 includes caustic alkali, carbonate, bicarbonate and thiosulfate.

[0028] Existing technologies use acidic electrolytes, but lead-free oxygen sensors using acidic electrolytes are prone to hydrogen evolution competition reactions, causing them to still output electrical signals even under oxygen-free conditions. This severely affects the accuracy of oxygen concentration measurement by the lead-free oxygen sensor. However, by using the electrolyte 20 of the present invention, which contains the aforementioned components, the above problems are completely avoided.

[0029] The preparation process of electrolyte 20 is described as follows: Cesium carbonate, cesium bicarbonate, and thiosulfate are dissolved in deionized water at room temperature and stirred for 15 minutes until completely dissolved, thereby preparing the electrolyte. The pH value of this electrolyte is 14 at room temperature.

[0030] Example 1: Cesium carbonate, potassium hydroxide, and potassium acetate were mixed in a molar ratio of 1:0:0 to prepare an electrolyte ①, which was then used to assemble a sensor.

[0031] Example 2: Cesium carbonate, potassium hydroxide, and potassium acetate were mixed in a molar ratio of 0:0.3:0.01 to prepare an electrolyte ②, which was then used to assemble a sensor.

[0032] Example 3: Cesium carbonate, potassium hydroxide, and potassium acetate were mixed in a molar ratio of 0:1:0 to prepare an electrolyte ③, which was then used to assemble a sensor.

[0033] Example 4: Cesium carbonate, potassium hydroxide, and potassium acetate were mixed in a molar ratio of 1.5:0.02:0 to prepare an electrolyte ④, which was then used to assemble a sensor.

[0034] Example 5: Cesium carbonate, potassium hydroxide, and potassium acetate were mixed in a molar ratio of 1:2:0.05 to prepare an electrolyte (⑤), which was used to assemble a sensor. Example 6: Cesium carbonate, potassium hydroxide, and potassium acetate were mixed in a molar ratio of 1:2.5:1 to prepare an electrolyte ⑥, which was then used to assemble a sensor.

[0035] The electrolyte prepared according to the above embodiments has good chemical properties and response characteristics, such as... Figure 2 As shown, it illustrates the response curve of the output electrical signal of the full-range lead-free oxygen sensor prepared according to the first embodiment of the present invention as a function of oxygen concentration. In this response curve, In addition, such as Figure 3 As shown, it illustrates the linear graphs of oxygen concentration versus voltage for full-range lead-free oxygen sensors prepared according to the first, second, and third embodiments of the present invention. In these linear graphs, In addition, Table 1 below shows the T90 recovery time and corresponding normoxic voltage for different embodiments.

[0036] Table 1 Figure 4 The linear relationship between oxygen concentration and voltage of the oxygen sensors prepared in Examples 1-6 above is shown in the graph. The linearity test method is as follows: A test board with the sensor inserted is placed in a sealed chamber. Nitrogen gas is first introduced into the chamber to purge all oxygen, and then oxygen is gradually introduced. The output voltage of the sensor is recorded sequentially from 0% to above 98% oxygen concentration. A linear graph is then plotted between the oxygen concentration and the corresponding output voltage data. The linear relationship graph shows that the linearity of this invention is very high.

[0037] Preferably, an oxygen-permeable membrane 60 is provided on the housing 10 at a position corresponding to the catalytic electrode 40.

[0038] In one embodiment, an anode pin 32 is provided on the side of the housing 10. The tin anode 30 is electrically connected to the anode pin 32 via an anode wire 34. The anode pin 32 is electrically connected to an external device, such as a control circuit board (not shown), and the tin anode 30 is controlled by the control circuit board, such as by providing voltage and tracking and monitoring its voltage changes.

[0039] Similarly, in one embodiment, a cathode pin 42 is also provided on the side of the housing 10. The catalytic electrode 40 is electrically connected to the cathode pin 42 via a cathode wire 44. The cathode pin 42 is electrically connected to an external device, such as a control circuit board (not shown), and the catalytic electrode 40 is controlled by the control circuit board, such as by providing voltage and tracking and monitoring its voltage changes.

[0040] In one embodiment, the oxygen-permeable membrane 60 may be a PTFE membrane; in other embodiments, the oxygen-permeable membrane 60 may also be made of other suitable materials.

[0041] Furthermore, in one embodiment, the catalytic electrode 40 can be made of various suitable materials, such as any one of the following metals: carbon, platinum, gold, silver, and copper, or an alloy formed by any two or more of these materials. These materials have higher conductivity and facilitate electrochemical reactions.

[0042] Preferably, the anode wire 34 and / or cathode wire 44 are made of a metallic material with good conductivity and corrosion resistance, such as gold, silver, copper, or nickel, or an alloy formed by combining any two or more materials. Similarly, the anode pin 32 and / or cathode pin 42 can also be made of a metallic material with good conductivity and corrosion resistance, such as gold, silver, copper, or nickel, or an alloy formed by combining any two or more materials.

[0043] Those skilled in the art will understand that the steps, measures, and solutions in the various operations, methods, and processes discussed in this application can be alternated, modified, combined, or deleted. Furthermore, other steps, measures, and solutions in the various operations, methods, and processes discussed in this application can also be alternated, modified, rearranged, decomposed, combined, or deleted. Furthermore, steps, measures, and solutions in the prior art that are similar to those disclosed in this application can also be alternated, modified, rearranged, decomposed, combined, or deleted.

[0044] The above description is only a partial embodiment of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this application, and these improvements and modifications should also be considered within the scope of protection of this application.

Claims

1. A full-range lead-free oxygen sensor, comprising: The package comprises a housing, an electrolyte placed within the housing, a tin anode and a catalytic electrode immersed in the electrolyte, wherein an electrolyte adsorption membrane is disposed between the tin anode and the catalytic electrode, characterized in that the electrolyte comprises caustic alkali, carbonate, bicarbonate and thiosulfate.

2. The full-range lead-free oxygen sensor according to claim 1, characterized in that: The electrolyte comprises cesium carbonate, cesium bicarbonate, and sodium thiosulfate, with a molar concentration ratio between the three of them ranging from 1:0.1:0.003 to 1:0.1:0.

05.

3. The full-range lead-free oxygen sensor according to claim 2, characterized in that: The electrolyte comprises cesium carbonate, cesium bicarbonate, and sodium thiosulfate, with a molar concentration ratio of 1:0.1:0.

003.

4. The full-range lead-free oxygen sensor according to claim 2, characterized in that: The electrolyte comprises cesium carbonate, cesium bicarbonate, and sodium thiosulfate, with a molar concentration ratio of 1:0.1:0.

01.

5. The full-range lead-free oxygen sensor according to claim 2, characterized in that: The electrolyte comprises cesium carbonate, cesium bicarbonate, and sodium thiosulfate, with a molar concentration ratio of 1:0.1:0.

05.

6. The full-range lead-free oxygen sensor according to claim 1, characterized in that: An oxygen-permeable membrane is provided on the housing at the position corresponding to the catalytic electrode.

7. The full-range lead-free oxygen sensor according to claim 1, characterized in that: An anode pin is provided on the side of the housing, and the tin anode is electrically connected to the anode pin through an anode wire; a cathode pin is also provided on the side of the housing, and the catalytic electrode is electrically connected to the cathode pin through a cathode wire.

8. The full-range lead-free oxygen sensor according to claim 6, characterized in that: The oxygen-permeable membrane is a PTFE membrane.

9. The full-range lead-free oxygen sensor according to claim 7, characterized in that: The catalytic electrode is made of any one of the following materials: carbon, platinum, gold, silver, and copper, or an alloy formed by any two or more of these materials.

10. The full-range lead-free oxygen sensor according to claim 9, characterized in that: The anode wire and / or cathode wire are made of one of the following metals: gold, silver, copper, or nickel, or an alloy formed by combining any two or more of these materials.

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