A pure titanium material coating sensor for detecting nitric oxide and a preparation method and application thereof

Abstract

The application relates to the field of coating materials, and discloses a pure titanium material coating sensor for detecting nitric oxide and a preparation method and application thereof. The sensor comprises a pure titanium material, a micro-arc oxidation coating and an electrode; the micro-arc oxidation coating is arranged on the surface of the pure titanium material through micro-arc oxidation of a sodium phosphate, sodium tungstate and sodium stannate electrolyte; and the electrode is arranged on the micro-arc oxidation coating. The SnO2-WO3 coating capable of being applied to low-concentration nitric oxide detection is formed on the surface of the pure titanium material through micro-arc oxidation of the composite electrolyte of sodium phosphate, sodium tungstate and sodium stannate; the electrode is arranged, and the oxygen adsorption-desorption principle is utilized for detection; compared with conventional gases, nitric oxide shows excellent sensitivity and selectivity, and therefore, nitric oxide can be effectively, real-timely and simply detected.

Description

Technical Field

[0001] This invention relates to the field of coating materials, specifically to a pure titanium material coating sensor for detecting nitric oxide, its preparation method, and its application. Background Technology

[0002] Nitric oxide (NO), colorless and odorless, is a harmful gas that threatens human survival, mostly produced by the combustion of fossil fuels in industrial production. High concentrations (25 ppm) can impair nerve function and cause neurodegeneration and other diseases. At the same time, NO is also the simplest bioactive molecule in the body, playing a crucial biological role in the cardiovascular, cerebrovascular, immune, nervous, urinary, and reproductive systems. For example, the concentration of NO in the breath of healthy individuals is typically below 25 ppb, while it is above 50 ppb in patients with asthma or airway inflammation. Therefore, its detection in daily life is becoming increasingly important. However, effective detection of NO in respiration remains a challenge, such as developing inexpensive and portable devices. Therefore, there is an urgent need for stable and effective detection of low concentrations of NO.

[0003] Currently, conventional methods for detecting NO have been established, including electrochemical, high-performance liquid chromatography, gas chromatography, polarography, and fluorescence methods. Although these methods are widely used, their large-scale application is still limited due to their high cost, operational complexity, and, in particular, unsuitability for real-time detection. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide a sensor for detecting nitric oxide coatings made of pure titanium material, which can have a high sensitivity response to NO in low concentration environments and excellent selectivity for other VOC gases.

[0005] Another object of the present invention is to provide a method for preparing the above-mentioned sensor and its application in detecting nitric oxide and preparing products for detecting nitric oxide.

[0006] To solve the above-mentioned technical problems, or at least partially solve the above-mentioned technical problems, the present invention provides a method for solving the above-mentioned technical problems, or at least partially solve the above-mentioned technical problems. As a first aspect of the present invention, a pure titanium composite coating sensor for detecting nitric oxide is provided, comprising pure titanium material, micro-arc oxidation coating and electrode; the micro-arc oxidation coating is disposed on the surface of the pure titanium material by micro-arc oxidation with sodium phosphate, sodium tungstate and sodium stannate electrolyte, and the electrode is disposed on the micro-arc oxidation coating.

[0007] Optionally, the pure titanium material includes TA1 to TA4 industrial pure titanium materials.

[0008] Optionally, the electrode is an interdigitated electrode.

[0009] Optionally, the concentration of sodium phosphate in the electrolyte is 8-12 g / L, the concentration of sodium tungstate is 1-2 g / L, and the concentration of sodium stannate is 1-2 g / L.

[0010] As a second aspect of the present invention, based on the superior performance of the sensor of the present invention in detecting nitric oxide, exhibiting high sensitivity and selectivity, the present invention provides the application of the sensor in detecting nitric oxide or in the preparation of products for detecting nitric oxide. The nitric oxide comprises 0.1 to 200 ppm of nitric oxide.

[0011] As a third aspect of the present invention, a method for preparing the sensor is provided, comprising:

[0012] Step 1: Pre-treatment of pure titanium material, including grinding, degreasing, and cleaning;

[0013] Step 2: The pretreated pure titanium material is subjected to micro-arc oxidation in an electrolyte of sodium phosphate, sodium tungstate and sodium stannate to form a micro-arc oxidation coating.

[0014] Step 3: Set electrodes on the micro-arc oxidation coating to obtain the sensor.

[0015] As a fourth aspect of the invention, a product for detecting nitric oxide is provided, comprising a device for recording changes in resistance and a sensor as described in the invention, wherein electrodes on the device and the sensor are connected by wires.

[0016] Optionally, the device for recording changes in resistance values ​​includes a multimeter and a data processor.

[0017] As a fifth aspect of the present invention, a method for detecting nitric oxide is provided, wherein the sensor of the present invention is placed in nitric oxide standard samples of different concentrations, and a standard curve of resistance change data and nitric oxide concentration is established by a device for recording resistance value changes; then the sensor is placed in the environment to be tested, resistance value change data is obtained, and the concentration of nitric oxide in the environment to be tested is obtained by the standard curve.

[0018] This invention utilizes a composite electrolyte of sodium phosphate, sodium tungstate, and sodium stannate for micro-arc oxidation to form a SnO2-WO3 coating on the surface of pure titanium material, which can be used for the detection of low concentrations of nitric oxide. By setting electrodes and utilizing the oxygen adsorption-desorption principle for detection, it exhibits excellent sensitivity and selectivity for nitric oxide compared to conventional gases, thus enabling effective, real-time, and convenient detection of nitric oxide. Attached image description:

[0019] Figure 1 The image shown is a SEM image of the sensor coating of this invention;

[0020] Figure 2 The image shown is an EDS diagram of the sensor coating of this invention;

[0021] Figure 3 The diagram shown is a schematic of the detection system.

[0022] Figure 4 The figure shows the response of the sensor prepared by electrolyte groups (1) to (4) in Example 1 to 0.1 to 200 ppm of nitric oxide; in the figure, numbers 1 to 4 represent electrolyte groups (1) to (4) respectively, and the scatter plots from top to bottom are the corresponding results of electrolyte groups (4), (3), (2) and (1);

[0023] Figure 5 The image shows the response of the sensors prepared by electrolyte groups (1) to (4) in Example 2 to nitric oxide (0.1 to 200 ppm); where 1-4 represent electrolyte groups (1) to (4) respectively, and the scatter plot from top to bottom shows the corresponding results of electrolyte groups (2), (4), (3), and (1);

[0024] Figure 6 The results show the response of the sensors prepared by electrolyte groups (5) to (8) in Example 2 to nitric oxide (0.1 to 200 ppm); where 1-4 represent electrolyte groups (5) to (8) respectively, and the scatter plot from top to bottom shows the results corresponding to electrolyte groups (3), (2), (4), and (1);

[0025] Figure 7 The image shows the response of the sensor prepared by electrolyte groups (1) to (2) in Example 3 to nitric oxide (0.1 to 200 ppm); where 1-2 represent electrolyte groups (1) to (2) respectively, and the scatter plot from top to bottom shows the corresponding results of electrolyte groups (2) and (1);

[0026] Figure 8 The results shown are the response of the sensors prepared by electrolyte groups (1) to (4) in Example 4 to nitric oxide (0.1 to 200 ppm); where 1 to 4 represent electrolyte groups (1) to (4) respectively, and the scatter plot from top to bottom shows the results corresponding to electrolyte groups (4), (3), (1), and (2);

[0027] Figure 9 The figure shows a bar chart of Ra / Rg values ​​for different detection gases (results of gas selectivity test);

[0028] Figure 10 The figure shows the fitting curves of the sensor of the present invention for detecting different concentrations of nitric oxide;

[0029] Figure 11 The figure shows the optimal operating temperature curve of the sensor of the present invention. Detailed implementation method:

[0030] This invention discloses a pure titanium material coated sensor for detecting nitric oxide, its preparation method, and its application. Those skilled in the art can refer to the content of this document and appropriately modify the process parameters to achieve the same result. It should be particularly noted that all similar substitutions and modifications are obvious to those skilled in the art and are considered to be included in this invention. The sensor, its preparation method, and its application have been described through preferred embodiments. Those skilled in the art can obviously make modifications or appropriate alterations and combinations to the sensor, its preparation method, and its application described herein without departing from the content, spirit, and scope of this invention to realize and apply the technology of this invention.

[0031] In a first aspect of the invention, a pure titanium composite coating sensor for detecting nitric oxide is provided, comprising pure titanium material, a micro-arc oxidation coating, and an electrode; the micro-arc oxidation coating is deposited on the surface of the pure titanium material via micro-arc oxidation using an electrolyte of sodium phosphate, sodium tungstate, and sodium stannate; the electrode is disposed on the micro-arc oxidation coating; and a SEM image of the sensor coating is provided. Figure 1 See EDS diagram Figure 2 .

[0032] In some embodiments of the present invention, the pure titanium material includes TA1 to TA4 industrial pure titanium materials, wherein Ti ≥ 99% is contained in the pure titanium material; in other embodiments of the present invention, the pure titanium material includes TA1 pure titanium material, and more specifically, the elemental composition (mass fraction) of the TA1 pure titanium material is: Fe: 0.2%, C: 0.08%, N: 0.03%, H: 0.015%, O: 0.18%, others: 0.4%, with the balance being Ti.

[0033] In some embodiments of the present invention, the electrode is an interdigital electrode.

[0034] In some embodiments of the present invention, the concentration of sodium phosphate in the electrolyte is 8–12 g / L, the concentration of sodium tungstate is 1–2 g / L, and the concentration of sodium stannate is 1–2 g / L. In other embodiments of the present invention, the concentration of sodium phosphate in the electrolyte is 8 g / L, 10 g / L, or 12 g / L, the concentration of sodium tungstate is 1 g / L or 2 g / L, and the concentration of sodium stannate is 1 g / L or 2 g / L.

[0035] The sensor described in this invention detects nitric oxide gas based on the resistance change of a metal oxide layer formed by micro-arc oxidation and coating exposed to air and nitric oxide gas, according to the principle of "oxygen adsorption-desorption" of metal oxides. When the pure titanium coating material is exposed to air, oxygen extracts electrons from the conduction band of the coating, causing an increase in resistance. When NO is exposed to the pure titanium coating, NO reacts with adsorbed oxygen on the metal oxide coating surface in a redox reaction, releasing the captured electrons and decreasing the resistance, as shown in the following equation:

[0036]

[0037]

[0038]

[0039] NO(gas) + O - →NO2(gas)+e -

[0040]

[0041] In a comparison of different electrolytes, the nitric oxide responsivity was tested using the prepared pure titanium material. The results showed that electrolytes composed of sodium phosphate, sodium tungstate, and sodium stannate exhibited excellent performance and high sensitivity in NO detection under low concentration conditions.

[0042] Compared with common VOC gases such as triethylamine, ethanol, acetone, and formaldehyde, the responsivity of each gas detected using the pure titanium material described in this invention shows that its resistivity sensitivity (K = Ra / Rg) for nitric oxide is much higher than that for other gases. This indicates that the tungsten and tin doped coating on the surface of the pure titanium material of this invention not only has high sensitivity for low concentrations of nitric oxide but also good selectivity, reducing interference. In view of the beneficial effects of the sensor of this invention and its excellent performance in actual detection processes, in a second aspect of this invention, the application of the sensor in detecting nitric oxide or in the preparation of products for detecting nitric oxide is provided. The nitric oxide includes 0.1–200 ppm of nitric oxide.

[0043] In a third aspect of the invention, a method for preparing the sensor is also provided, comprising:

[0044] Step 1: Pre-treatment of pure titanium material, including grinding, degreasing, and cleaning;

[0045] Step 2: The pretreated pure titanium material is subjected to micro-arc oxidation in an electrolyte of sodium phosphate, sodium tungstate and sodium stannate to form a micro-arc oxidation coating.

[0046] Step 3: Set electrodes on the micro-arc oxidation coating to obtain the sensor.

[0047] In some embodiments of the present invention, step 1 is as follows:

[0048] The pure titanium material is polished in stages, followed by ultrasonic cleaning with anhydrous ethanol and water, and then degreasing and cleaning with an alkaline degreasing solution. The staged polishing uses silicon carbide sandpaper with progressively increasing grit, until the surface is smooth, free of obvious scratches, and has a uniform texture. The alkaline degreasing solution is sodium hydroxide, preferably a 10% sodium hydroxide solution.

[0049] To achieve a more uniform coating thickness, higher porosity, and submicron pores, which is beneficial for nitric oxide detection, in some embodiments of the present invention, the micro-arc oxidation is performed in a constant current mode. In other embodiments, the positive current in the constant current mode is preset to 2–8 A, and can be selected as 4 A; the negative current is preset to 1–5 A, and can be selected as 3 A; the pulse frequency is fixed at 0.1–0.3 Hz, and can be selected as 0.2 Hz; the duty cycle is set to 70%–90%, and can be selected as 80%. In other embodiments, in the constant current mode, the current ramp-up starts from 0 A and increases gradually in increments of 0.5 A until a preset value is reached, with both positive and negative currents occurring simultaneously. This allows for better quality of the prepared micro-arc oxidation coating and also protects the micro-arc oxidation power supply.

[0050] In some embodiments of the present invention, pure titanium is used as the positive electrode and other suitable metals such as stainless steel are used as the negative electrode, with the distance between the positive and negative electrodes controlled at 10 cm; the temperature of the electrolyte is controlled by an internal and external circulation cooling device and maintained at 20-35°C.

[0051] In some embodiments of the present invention, the micro-arc oxidation time can be selected according to the actual situation. In some embodiments of the present invention, the micro-arc oxidation time is 4 to 6 minutes, while in other embodiments, the micro-arc oxidation time is 4 minutes, 5 minutes or 6 minutes.

[0052] In some embodiments of the present invention, the electrode is fabricated as an interdigitated electrode by using a mask to cover the coating on the surface of the pure titanium material and then employing an ion sputtering process. In other embodiments of the present invention, the ion sputtering process uses a cyclic sputtering method, adjusting the sputtering duration and number of cycles according to the desired interdigitated electrode shape; in other embodiments of the present invention, the sputtering duration is 90 s and the number of cycles is 6.

[0053] In a fourth aspect of the invention, a product for detecting nitric oxide is provided, comprising a device for recording changes in resistance and a sensor as described in the invention, wherein electrodes on the device and the sensor are connected by wires.

[0054] In some embodiments of the present invention, the conductor is a conductive metal wire, such as a copper wire; in other embodiments of the present invention, the conductor is adhered to the electrode by conductive silver paste or other conductive materials to form a connection.

[0055] In some embodiments of the present invention, the device for recording changes in resistance value includes a multimeter and a data processor, wherein the multimeter may be a digital multimeter and the data processor may be a computer device.

[0056] In a fifth aspect of the present invention, a method for detecting nitric oxide is provided, wherein the sensor of the present invention is placed in nitric oxide standard samples of different concentrations, and a standard curve of resistance change data and nitric oxide concentration is established by a device for recording resistance value changes; then the sensor is placed in the environment to be tested, resistance value change data is obtained, and the concentration of nitric oxide in the environment to be tested is obtained by the standard curve.

[0057] Unless otherwise specified, the experimental environment and parameter conditions of each group in the specific implementation test are consistent, except for the differences that are explicitly pointed out.

[0058] The following is a further description of a pure titanium material coated sensor for detecting nitric oxide, its preparation method, and its application, provided by the present invention.

[0059] Example 1: Preparation of the sensor for nitric oxide detection according to the present invention

[0060] I. Preparation Method

[0061] 1. Pretreatment of pure titanium substrate

[0062] The pure titanium substrate is TA1 industrial pure titanium, with the following elemental composition (mass fraction): Fe: 0.2%, C: 0.08%, N: 0.03%, H: 0.015%, O: 0.18%, others: 0.4%, and the balance being Ti. The pure titanium substrate was wire-cut into 25mm × 25mm × 2mm pieces, and then polished with 400# → 800# → 1000# → 2000# silicon carbide sandpaper until the surface was smooth, without obvious scratches, and with a uniform texture. It was then ultrasonically cleaned for 10 minutes each in acetone, anhydrous ethanol, and deionized water, and finally air-dried with a hair dryer to obtain the pretreated pure titanium substrate.

[0063] Bright and clean pure titanium is immersed in a degreasing solution, which is a 10% sodium hydroxide solution at a temperature of 60°C, and then ultrasonically cleaned for 10 minutes. After removing the pure titanium, it is rinsed with water three times and then dried with a hair dryer to obtain a pure titanium substrate after ultrasonic treatment.

[0064] 2. Prepare the micro-arc oxidation electrolyte.

[0065] The micro-arc oxidation electrolyte formula consists of 8 g / L sodium phosphate, 1 g / L and 2 g / L sodium stannate, and 1 g / L and 2 g / L sodium tungstate. To prepare, first add 3 L of deionized water to the electrolytic cell, then add appropriate amounts of sodium phosphate, sodium tungstate, and sodium stannate, and dissolve them thoroughly. The micro-arc oxidation electrolyte needs to be replaced after each micro-arc oxidation operation, and each batch of prepared electrolyte must be used within 24 hours to prevent deterioration.

[0066] (1) 8 g / L sodium phosphate + 1 g / L sodium stannate + 1 g / L sodium tungstate;

[0067] (2) 8 g / L sodium phosphate + 1 g / L sodium stannate + 2 g / L sodium tungstate;

[0068] (3) 8 g / L sodium phosphate + 2 g / L sodium stannate + 1 g / L sodium tungstate;

[0069] (4) 8 g / L sodium silicate + 2 g / L sodium stannate + 2 g / L sodium tungstate;

[0070] 3. Micro-arc oxidation

[0071] Pretreated pure titanium was placed in a micro-arc oxidation electrolyte, with the pure titanium connected to the positive terminal of the power supply as the positive electrode, and the stainless steel electrolytic cell connected to the negative terminal as the cathode. The distance between the positive and negative electrodes was controlled at 10 cm. The cooling device was turned on, and the temperature was controlled at 30℃. A micro-arc oxidation AC pulse power supply was used to start the power supply. In constant current mode, the forward current was preset to 4A, and the negative current was preset to 3A. The current was increased from 0A in increments of 0.5A, with both positive and negative currents proceeding simultaneously until the preset values ​​were reached. The pulse frequency was fixed at 0.2Hz, the duty cycle was set to 80%, and the micro-arc oxidation time was 4 minutes. After this, pure titanium with a micro-arc oxidation coating on the surface was obtained.

[0072] 4. Ion sputtering

[0073] A mask was placed over the surface of the micro-arc oxidation coating and fixed in a vacuum ion sputtering instrument. The sputtering current was kept constant, and interdigitated electrodes were prepared by cyclic sputtering. Each sputtering lasted 90 seconds, and a total of 6 sputtering cycles were performed.

[0074] 5. Copper wire adhesion

[0075] After sputtering, the conductivity was tested using a multimeter to assess the processing quality of the interdigitated electrodes. Then, copper wires were adhered to the interdigitated electrodes using conductive silver paste and dried at 80°C for 2 hours to ensure good contact in the sensor circuitry.

[0076] SEM and EDS images of the sensor coating prepared in this invention are shown below. Figure 1 and Figure 2 ,Depend on Figure 1 SEM images show that the prepared film has uniform pores on its surface, with pore sizes ranging from micrometers to nanometers, which is beneficial to its gas-sensing performance. From... Figure 2 As shown in the EDS, Sn and W elements were successfully incorporated into the surface of the micro-arc TiO2 film.

[0077] Reference Figure 3 The detection system shown was tested by setting up a heating platform in a closed space and placing the sensor prepared in this invention on it. Copper wires were attached to the interdigital electrodes with conductive silver paste and connected to a multimeter. Data transmission was established between the multimeter and the computer.

[0078] A fixed amount of volatile gas solution is injected into a closed space. The gas is rapidly evaporated into gas by a heating platform. The gas reacts with the sensor to generate a signal. A thermometer is used to indicate the temperature of the closed space. A fan is used to quickly remove the measured volatile gas after the detection is completed.

[0079] Figure 4 The results are the NO resistivity ratio sensitivity (K=Ra / Rg) detection results under different electrolyte conditions, from... Figure 4 It can be seen that when the concentration of sodium stannate is 2 g / L and the concentration of sodium tungstate is 2 g / L, the sensitivity to 0.1–200 ppm NO is the highest.

[0080] Example 2: Effect of different tin and tungsten doping concentrations on the performance of low nitric oxide concentration gas sensors

[0081] 1. Test Methods

[0082] Refer to Example 1;

[0083] 2. The Influence of Different Coatings on Nitric Oxide Detection

[0084] The preparation method is the same as in Example 1, except that the composition of the electrolyte is adjusted.

[0085] (1) 10 g / L sodium phosphate + 1 g / L sodium stannate + 1 g / L sodium tungstate;

[0086] (2) 10 g / L sodium phosphate + 1 g / L zinc stannate + 2 g / L sodium tungstate;

[0087] (3) 10 g / L sodium phosphate + 2 g / L sodium stannate + 1 g / L sodium tungstate;

[0088] (4) 10 g / L sodium phosphate + 2 g / L sodium stannate + 2 g / L sodium tungstate;

[0089] (5) 12 g / L sodium phosphate + 1 g / L sodium stannate + 1 g / L sodium tungstate;

[0090] (6) 12 g / L sodium phosphate + 1 g / L sodium stannate + 2 g / L sodium tungstate;

[0091] (7) 12 g / L sodium phosphate + 2 g / L sodium stannate + 1 g / L sodium tungstate;

[0092] (8) 12 g / L sodium phosphate + 2 g / L sodium stannate + 2 g / L sodium tungstate;

[0093] The resistivity sensitivity (K = Ra / Rg) of the above 8 groups of electrolytes was measured, and the results are shown in the figure. Figure 5 and Figure 6 ;

[0094] Figure 5 The results showed that sodium phosphate concentration of 10 g / L, sodium stannate concentration of 1 g / L, and sodium tungstate concentration of 2 g / L exhibited better responses to NO, but were much smaller than the responses of the parameters in Example 1.

[0095] Figure 6 The results showed that sodium phosphate concentration of 12 g / L, sodium stannate concentration of 2 g / L, and sodium tungstate concentration of 1 g / L exhibited better responses to NO, but were much smaller than the responses of the parameters in Example 1.

[0096] Example 3: The effect of removing substances from the electrolyte on the NO gas sensing performance

[0097] 1. Test Methods

[0098] Refer to Example 1;

[0099] 2. The Influence of Different Coatings on Nitric Oxide Detection

[0100] The preparation method is the same as in Example 1, except that the composition of the electrolyte is adjusted.

[0101] (1) 8 g / L sodium phosphate + 2 g / L sodium stannate;

[0102] (2) 8 g / L sodium phosphate + 2 g / L sodium tungstate;

[0103] Figure 7 The results showed that the prepared gas-sensitive membrane layer had a poor response to NO, lower than the parameter response of Examples 1 and 2, and poor sensing performance.

[0104] Example 4: Effect of replacing substances in the electrolyte on NO gas sensing performance

[0105] 1. Test Methods

[0106] Refer to Example 1;

[0107] 2. The Influence of Different Coatings on Nitric Oxide Detection

[0108] The preparation method is the same as in Example 1, except that the composition of the electrolyte is adjusted.

[0109] (1) 8 g / L sodium phosphate + 2 g / L sodium stannate + 2 g / L sodium borate;

[0110] (2) 8 g / L sodium phosphate + 2 g / L sodium stannate + 2 g / L sodium molybdate;

[0111] (3) 8 g / L sodium phosphate + 2 g / L sodium tungstate + 2 g / L sodium borate;

[0112] (4) 8 g / L sodium phosphate + 2 g / L sodium tungstate + 2 g / L sodium molybdate;

[0113] Figure 8 The results showed that the prepared gas-sensitive membrane layer had a poor response to NO, lower than the parameter response of Examples 1 and 2, and poor sensing performance.

[0114] Example 5: Gas Selectivity Test and Fitting Curve

[0115] 1. Gas selectivity test

[0116] The optimal electrolyte and detection system were used as described in Example 1. Once the sensor stabilized at the preset temperature, a solution of the preset gas (20 ppm of nitric oxide, triethylamine, ethanol, acetone, and formaldehyde) was added dropwise. The results are shown below. Figure 9 ; Figure 9 The results showed that 20 ppm NO exhibited excellent response at 210 °C. The resistivity sensitivity of each gas showed that NO's response was significantly higher than that of the other volatile gases, indicating that it had extremely high sensitivity and strong selectivity for ammonia.

[0117] 2. Fitting curve experiment at different concentrations

[0118] Refer to the optimal electrolyte group and detection system in Example 1. Once the sensor stabilizes at the preset temperature, start adding nitric oxide solutions of different concentrations (0.1ppm, 0.5ppm, 1ppm, 5ppm, 10ppm, 20ppm, 50ppm, 80ppm, 100ppm, 150ppm, 200ppm). Figure 10 The results show that the sensor of the present invention exhibits a good linear relationship (R0) for detecting nitric oxide. 2 =0.96).

[0119] 3. Optimal operating temperature

[0120] The optimal electrolyte and detection system were tested according to Example 1. The prepared gas-sensitive membrane was placed in different temperature environments (150℃~240℃), and its response at 20ppm was observed. Figure 11The optimal operating temperature of the NO-sensitive membrane is 210℃.

[0121] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A pure titanium material coated sensor for detecting nitric oxide, characterized in that, The device includes pure titanium material, a micro-arc oxidation coating, and an electrode. The micro-arc oxidation coating is applied to the surface of the pure titanium material via micro-arc oxidation using an electrolyte composed of sodium phosphate, sodium tungstate, and sodium stannate. The electrode is disposed on the micro-arc oxidation coating. The concentration of sodium phosphate in the electrolyte is 8–12 g / L, the concentration of sodium tungstate is 1–2 g / L, and the concentration of sodium stannate is 1–2 g / L.

2. The sensor according to claim 1, characterized in that, The pure titanium material includes TA1 to TA4 industrial pure titanium materials.

3. The sensor according to claim 1, characterized in that, The electrode is an interdigitated electrode.

4. The use of the sensor according to any one of claims 1-3 in detecting nitric oxide or in the preparation of products for detecting nitric oxide.

5. The application according to claim 4, characterized in that, The nitric oxide comprises 0.1 to 20 ppm of nitric oxide.

6. The method for preparing the sensor according to claim 1, characterized in that, include: Step 1: Pre-treatment of pure titanium material, including grinding, degreasing, and cleaning; Step 2: The pretreated pure titanium material is subjected to micro-arc oxidation in an electrolyte of sodium phosphate, sodium tungstate and sodium stannate to form a micro-arc oxidation coating. Step 3: Set electrodes on the micro-arc oxidation coating to obtain the sensor.

7. A product for detecting nitric oxide, characterized in that, The device includes a device for recording changes in resistance and a sensor as described in any one of claims 1-3, wherein the electrodes on the device and the sensor are connected by wires.

8. The product according to claim 7, characterized in that, The device for recording changes in resistance values ​​includes a multimeter and a data processor.

9. A method for detecting nitric oxide, characterized in that, The sensor described in any one of claims 1-3 is placed in nitric oxide standard samples of different concentrations, and a standard curve of resistance change data and nitric oxide concentration is established by a device that records the change in resistance value; then the sensor is placed in the environment to be tested, and resistance change data is obtained, and the concentration of nitric oxide in the environment to be tested is obtained by the standard curve.

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