A tin dioxide / polyaniline composite nanometer carbon monoxide sensor material and a preparation method thereof

Abstract

The application discloses a kind of tin dioxide / polyaniline composite nano carbon monoxide sensor materials and preparation method, comprising the following steps: A, to tin salt solution, add NaOH solution, precipitate solution is transferred to autoclave and is cooled to room temperature, after washing and drying, obtain tin oxide;B, aniline monomer is dissolved with tin oxide in acid solution, then add acid solution dissolved with ammonium persulfate, under ice bath condition, centrifugation is carried out to obtain precipitate, to obtain composite;C, composite is placed in porcelain boat, with tube furnace activation treatment, after cooling, it is obtained.The sensor material of the application avoids the problems of high working temperature, high power consumption and high cost of traditional metal semiconductor oxide sensor material, and improves the corrosion resistance of the sensor by constructing MOF framework structure and synthesizing polyaniline, which can adapt to the internal environment of lithium ion battery.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of sensor materials, in particular to a tin dioxide / polyaniline composite carbon monoxide sensor material and a preparation method thereof. BACKGROUND

[0002] Carbon monoxide is one of the most dangerous toxic gases in human life, which is mainly produced in incomplete combustion of fuel, such as cooking, heating, automobile operation, etc., and can quickly threaten the safety of human life when a fire or a mine gas explosion occurs. Therefore, in the fields of chemical industry, energy production, automobile industry and family life, it is necessary to detect carbon monoxide in the environment. At present, the carbon monoxide sensors that are more commonly used include electrochemical type, heat conduction type and semiconductor type. The heat conduction type sensor has the problems of low sensitivity and low selectivity. The electrochemical carbon monoxide sensor is most widely used, has high sensitivity and fast response, but the leakage of electrolyte during use will affect its service life, and the price is relatively high. The semiconductor type sensor is more and more concerned by people due to its advantages of good stability, simple structure and low price.

[0003] The thermal runaway of lithium ion batteries has always been a hot issue in the field of new energy technology. The thermal runaway of lithium ion batteries is roughly divided into three characteristic temperatures: the starting temperature T1 of self-heat, the trigger temperature T2 of thermal runaway and the maximum temperature T3 of thermal runaway. The important source of heat in the temperature range of T1-T2 is the decomposition of the SEI film on the negative electrode surface and the reduction gas (such as hydrogen, carbon monoxide, etc.) produced again, which passes through the diaphragm and reacts with the positive electrode, causing the thermal trigger temperature T2 to be advanced, and ultimately leading to the thermal runaway of the battery. Using a sensor to detect the gas inside the lithium ion battery to warn of the thermal runaway problem of the lithium ion battery is an effective method, but the existing sensor is not yet mature enough to be applied in the lithium ion battery. The ideal sensor material is a semiconductor oxide sensor, but its high working temperature (200-300 DEG C) and the need to dope noble metals to improve sensitivity limit its application in lithium ion batteries. At the same time, due to the special environment inside the lithium ion battery, the sensor material is also required to have the ability to resist electrolyte corrosion, and at present there is no suitable sensor material that can meet these requirements. SUMMARY

[0004] The application aims at providing a tin dioxide / polyaniline composite nanometer carbon monoxide sensor material and a preparation method thereof.

[0005] The technical scheme adopted by the application is as follows: a preparation method of a tin dioxide / polyaniline composite nanometer carbon monoxide sensor material, comprising the following steps:

[0006] A. Dissolve a tin salt in deionized water, then add a NaOH solution, stir and precipitate, transfer the precipitate solution to an autoclave for hydrothermal treatment, cool to room temperature, centrifuge to obtain the precipitate, then clean, dry, grind into powder, and obtain tin oxide;

[0007] B. Dissolve an aniline monomer and the tin oxide in an acid solution, then add an acid solution containing ammonium persulfate, react under ice bath conditions, centrifuge to obtain the precipitate, wash, dry, grind into powder, and obtain a composite;

[0008] C. Put the composite into a porcelain boat, activate and treat with a tube furnace at 200-550 DEG C for 1-5 h, naturally cool to room temperature, and obtain the product.

[0009] Further, the tin salt is stannous chloride, and the acid solution is a hydrochloric acid solution.

[0010] Further, the molar ratio of the tin salt to the NaOH is 1:1-3, for example, 1:1, 1:2, 1:3, etc., and is preferably 1:2.

[0011] Further, in step A, the tin salt is dissolved in deionized water to obtain a tin salt solution, ultrasonic treatment is performed for 30-60 min, then the NaOH solution is added under magnetic stirring, and the magnetic stirring speed is 450-600 r / min.

[0012] Further, in step A, the hydrothermal treatment condition of the autoclave is 150-200 DEG C (for example, 150 DEG C, 160 DEG C, 180 DEG C, 200 DEG C, etc., and is preferably 160 DEG C), and the hydrothermal treatment time is 2-6 h.

[0013] Further, in step A, the centrifugal speed is 8000-10000 r / min.

[0014] Further, in step B, the mass ratio of aniline monomer to tin oxide is 1-20:100, for example, it can be 1:100, 5:100, 10:100, 12:100, 15:100, 18:100, 20:100, etc.

[0015] Further, in step B, the molar ratio of ammonium persulfate to aniline is 1:1.

[0016] Further, in step B, the temperature of the ice bath is 0-5℃, and the ice bath time is 6-8h.

[0017] Further, the present application also includes a tin dioxide / polyaniline composite nanometer carbon monoxide sensor material, which is prepared by the above preparation method.

[0018] In summary, due to the adoption of the above technical scheme, the present application has the following beneficial effects:

[0019] 1. The tin dioxide-polyaniline composite nanometer carbon monoxide sensor material prepared by the present application has a working temperature of only about 140℃, and its sensitivity meets the performance requirements without doping noble metals, compared with existing carbon monoxide sensor materials, the preparation process is simple, the cost is low, and the product performance is better.

[0020] 2. The present application improves the corrosion resistance of the sensor by constructing a MOF gold metal organic framework structure and synthesizing polyaniline by proton acid doping, so that it can adapt to the internal environment of lithium ion batteries and has better performance stability than existing carbon monoxide sensor materials, and has good application prospect in lithium ion battery thermal runaway gas detection and early warning. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 is a physical diagram of the tin dioxide / polyaniline composite nanometer carbon monoxide sensor material prepared in Example 1;

[0022] Figure 2 is an SEM diagram of the tin dioxide / polyaniline composite nanometer carbon monoxide sensor material prepared in Example 1;

[0023] Figure 3 is an XPS diagram of the tin dioxide / polyaniline composite nanometer carbon monoxide sensor material prepared in Example 1;

[0024] Figure 4 is a response diagram of the sensor material of Example 1 under different CO concentrations;

[0025] Figure 5 is a response diagram of the sensor material of Example 1 to different gases;

[0026] Figure 6is a photo of MQ-7B SnO2-based commercial CO sensor;

[0027] Figure 7 is a photo of SnO2 / polyaniline CO sensor of embodiment 1 of the present application;

[0028] Figure 8 is a comparison chart of responses of sensor material of embodiment 1 and commercial CO sensor at different CO concentrations;

[0029] Figure 9 is a comparison chart of performances of embodiment 1 of the present application and commercial CO sensor after electrolyte corrosion for 1 day. DETAILED DESCRIPTION

[0030] The present application will be described in detail below with reference to the accompanying drawings.

[0031] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and do not limit the present application.

[0032] A SnO2 / polyaniline composite nano carbon monoxide sensor material, a preparation method thereof comprises the following steps:

[0033] S1, SnCl2·2H2O and NaOH are used as raw materials, which are dissolved in deionized water in a molar ratio of 1:1-3, respectively, and ultrasonic dispersion treatment is performed for 30-60 min, to obtain a tin salt solution and a NaOH solution, respectively, the NaOH solution is added under magnetic stirring at a stirring speed of 450-600 r / min, after the reaction is completed, it is transferred to an autoclave, and hydrothermal treatment is performed at 150-200℃ for 2-6h, centrifugation is performed (at a centrifugal speed of 8000-10000 r / min) to obtain a precipitate, which is washed with anhydrous ethanol and deionized water until neutral, and then dried at 60℃ with air blowing, ground into powder, to obtain a tin oxide powder;

[0034] S2, tin oxide powder 1000mg, aniline monomer solution 0.24mL (equivalent to 20% of SnO2 mass, of course, other mass ratios can also be used), mixed and added to a HCl solution with a concentration of 0.9-1.1mol / L, ultrasonic dispersion for 30min, then dropwise addition of a HCl solution with ammonium persulfate dissolved therein at a molar ratio of 1:1 with the aniline monomer (HCl concentration of the HCl solution is 0.9-1.1mol / L), polymerization at 0-5℃ under ice bath for 6-8h, centrifugation (centrifugal speed is 8000-10000r / min) collection, 60℃ air drying, then the composite is placed in a porcelain boat, activation treatment in a tube furnace at 200-550℃ under N2 environment (nitrogen flow rate is 55-65mL / min) for 1-5h, after cooling, the product is taken out.

[0035] The obtained sensor material is ground with deionized water for about 15min, then applied to a flat plate electrode, and aged on an aging platform at 30mA for 24-48h, the sensor resistance decreases when different concentrations of CO gas are passed through, and the sensor response can be calculated according to the resistance decrease value ΔR corresponding to different gas concentrations.

[0036] In order to better explain the present application, the following part lists some specific examples:

[0037] Example 1

[0038] A tin dioxide / polyaniline composite carbon monoxide sensor material, the preparation method comprising the following steps:

[0039] S1, SnCl2·2H2O and NaOH are used as raw materials, and are dissolved in deionized water respectively according to a molar ratio of 1:2, and ultrasonic dispersion treatment is performed for 30min, tin salt solution and NaOH solution are obtained respectively, the NaOH solution is added under magnetic stirring at a stirring speed of 500r / min, after the reaction is completed, it is transferred to an autoclave, hydrothermal treatment is performed at 180℃ for 4h, centrifugation (centrifugal speed is 8000r / min) is performed to obtain a precipitate, the precipitate is washed with anhydrous ethanol and deionized water until it is neutral, 60℃ air drying is performed, and then grinding into powder to obtain tin oxide powder;

[0040] S2, tin oxide powder 1000 mg, aniline monomer solution 0.24 mL, mixed into a 1.0 mol / L HCl solution, ultrasonic dispersion for 30 min, then dropwise add to dissolve with aniline monomer molar ratio of 1:1 of ammonium persulfate in HCl solution (HCl concentration of HCl solution is 1.0 mol / L), 0°C ice bath polymerization 6h, centrifugal (centrifugal speed is 8000r / min) collection, 60°C air drying, the composite is placed in a porcelain boat, in N2environment (nitrogen flow rate is 60 mL / min) tube furnace 550°C (heating rate is 5°C / min) activation treatment 3h, after cooling, take out, namely obtained.

[0041] The tin dioxide-polyaniline composite nanometer carbon monoxide sensor material prepared above is shown in the actual figure Figure 1 , the SEM image is shown in Figure 2 , Figure 3 , the XPS image of the material is shown in Figure 2 , it is found that the PANI precursor provides a good framework structure, and the SnO2 nanoparticles loaded on the surface are uniformly distributed, it can be speculated that the SnO2 / PANI composite sensor material has been successfully prepared; from Figure 3 , in the XPS analysis image of the SnO2 / PANI composite material, the full spectrum (a) can be seen that the composite material mainly contains C, O, Sn, N four elements, because the ionization interface of H element is small, therefore cannot be detected. By narrow spectrum peak fitting of C, N, Sn elements respectively, (b), (c), (d) figures are obtained, from figure (c), it can be seen that there are -N=, -NH-, -NH + three ionic bonds in SnO2 / PANI composite material, the corresponding binding energy is 397eV, 399-400eV and 401-402eV, further indicating that the SnO2 / PANI composite material is successfully prepared.

[0042] The obtained sensor material is ground with deionized water for about 15 minutes, then brushed on a flat plate electrode, and aged on an aging platform under the condition of 30mA for 30h, then 400ppm of CO gas is introduced, the response of the sensor is 46%.

[0043] Further test, respectively introduce 10ppm, 20ppm, 50ppm, 100ppm, 200ppm, 300ppm, 400ppm of CO gas, the test results are shown in Figure 4 , the greater the concentration of CO gas in the test environment, the more the sensor resistance value decreases, the stronger the sensor response, the response is 85.6% when the concentration is 400ppm.

[0044] Further test, respectively, 10ppm, 20ppm, 50ppm, 100ppm, 200ppm, 300ppm, 400ppm of CO, H2, C2H4, CO2, CH4 five kinds of gas, test results as shown in Figure 5 The results show that the sensor resistance shows different changes in different gas environments, and the sensor shows the best selectivity to CO.

[0045] Further test, the sensor of example 1 is as shown in Figure 7 The market-purchased SnO2-based commercial CO sensor (MQ-7B) is aged together, and the sensor is as shown in Figure 6 Under the same test conditions, 10ppm, 20ppm, 50ppm, 100ppm, 200ppm, 300ppm, 400ppm of CO gas are respectively introduced, and the response of the two sensors to different gas concentrations is compared as shown in Figure 8 It can be known from Figure 8 The sensor material of the present application has relatively optimal gas-sensitive performance under laboratory test conditions.

[0046] Further test, the market-purchased SnO2-based commercial CO sensor (MQ-7B) and the sensor of example 1 are placed in a screw thread bottle with 40mL of electrolyte (1.0M LiPF6 in EC:DMC=1:1Vol%) in a sealed tank with appropriate size, the screw thread bottle cap is opened, the sealed tank cap is covered, and the entire corrosion experiment is carried out in a glove box argon environment, after 24h, the sensor is taken out, and is purged for 1h under a fume hood, after the VOC type gas on the surface is blown away, the test is carried out, and the gas-sensitive performance of the corroded sensor is compared as shown in Figure 9 It can be known from Figure 9 The sensitivity of the sensor material of the present application does not decrease obviously, it can still be used to detect CO gas, which shows that the electrolyte corrosion resistance of the sensor material is obviously better than that of the existing sensor material, and it can be applied in lithium ion batteries.

[0047] Example 2

[0048] A tin dioxide / polyaniline composite carbon monoxide sensor material, a preparation method thereof comprises the following steps:

[0049] S1, SnCl2·2H2O and NaOH were used as raw materials, which were dissolved in deionized water respectively according to a molar ratio of 1:1.8, and ultrasonic dispersion treatment was carried out for 30 min, to obtain a tin salt solution and a NaOH solution respectively. The NaOH solution was added under magnetic stirring at a stirring speed of 450 r / min. After the reaction was completed, it was transferred to an autoclave and hydrothermal treatment was carried out at 150 ℃ for 6 h. The precipitate was obtained by centrifugation at a speed of 8000 r / min, washed with anhydrous ethanol and deionized water until neutral, dried at 60 ℃, ground into powder, and tin oxide powder was obtained;

[0050] S2, 1000 mg of tin oxide powder and 0.24 mL of aniline monomer solution were weighed and added to a 1.0 mol / L HCl solution. Ultrasonic dispersion was carried out for 30 min, and then 1:1 ammonium persulfate dissolved in HCl solution (HCl concentration of HCl solution was 1.0 mol / L) was added dropwise. Polymerization was carried out at 1-2 ℃ for 7 h under ice bath, and the product was collected by centrifugation at a speed of 8000 r / min and dried at 60 ℃. The composite was placed in a porcelain boat and activated in a tube furnace at 500 ℃ under N2 environment (N2 flow rate was 60 mL / min) for 4 h. After cooling, the product was obtained.

[0051] Example 3

[0052] A tin dioxide / polyaniline composite nanometer carbon monoxide sensor material, the preparation method comprising the following steps:

[0053] S1, SnCl2·2H2O and NaOH were used as raw materials, which were dissolved in deionized water respectively according to a molar ratio of 1:1.8, and ultrasonic dispersion treatment was carried out for 30 min, to obtain a tin salt solution and a NaOH solution respectively. The NaOH solution was added under magnetic stirring at a stirring speed of 450 r / min. After the reaction was completed, it was transferred to an autoclave and hydrothermal treatment was carried out at 150 ℃ for 6 h. The precipitate was obtained by centrifugation at a speed of 8000 r / min, washed with anhydrous ethanol and deionized water until neutral, dried at 60 ℃, ground into powder, and tin oxide powder was obtained;

[0054] S2, 1000 mg of tin oxide powder, 0.2 mL of aniline monomer solution were weighed and mixed into a 1.0 mol / L HCl solution, ultrasonic dispersion for 30 min, then dropwise addition of a HCl solution dissolved with ammonium persulfate in a molar ratio of 1:1 with the aniline monomer (HCl concentration of the HCl solution was 1.0 mol / L), polymerization in an ice bath at 3-5°C for 6 h, centrifugal collection (centrifugal speed was 8000 r / min), after air drying at 60°C, the composite was placed in a porcelain boat, activated in a tube furnace at 350°C (heating rate was 3°C / min) under N2 environment (nitrogen flow rate was 60 mL / min) for 5 h, after cooling, it was taken out, and the tin dioxide / polyaniline composite nanometer carbon monoxide sensor material was obtained.

[0055] Example 4

[0056] A tin dioxide / polyaniline composite nanometer carbon monoxide sensor material, the preparation method comprising the following steps:

[0057] S1, SnCl2·2H2O and NaOH were used as raw materials, and they were respectively dissolved in deionized water in a molar ratio of 1:2 and ultrasonic dispersion treatment for 30 min, to obtain a tin salt solution and a NaOH solution, respectively, the NaOH solution was added under magnetic stirring at a stirring speed of 450 r / min, after the reaction was completed, it was transferred to an autoclave and hydrothermal treatment was carried out at 180°C for 4 h, centrifugal collection (centrifugal speed was 8000 r / min) was carried out, after washing with anhydrous ethanol and deionized water until neutral, air drying at 60°C, grinding into powder, tin oxide powder was obtained;

[0058] S2, 1000 mg of tin oxide powder, 0.24 mL of aniline monomer solution were weighed and mixed into a 1.0 mol / L HCl solution, ultrasonic dispersion for 30 min, then dropwise addition of a HCl solution dissolved with ammonium persulfate in a molar ratio of 1:1 with the aniline monomer (HCl concentration of the HCl solution was 1.0 mol / L), polymerization in an ice bath at 0°C for 6 h, centrifugal collection (centrifugal speed was 8000 r / min), after air drying at 60°C, the composite was placed in a porcelain boat, activated in a tube furnace at 500°C (heating rate was 4°C / min) under N2 environment (nitrogen flow rate was 60 mL / min) for 3 h, after cooling, it was taken out, and the tin dioxide / polyaniline composite nanometer carbon monoxide sensor material was obtained.

[0059] Comparative Example 1

[0060] Comparative Example 1 was the same as Example 1, except that the activation temperature was 700°C.

[0061] Comparative Example 2

[0062] Comparative Example 2 was the same as Example 1, except that no activation treatment was carried out.

[0063] Comparative Example 3

[0064] Comparative Example 3 is the same as Example 1, except that the amount of aniline monomer added is 0.4 mL.

[0065] Comparative Example 4

[0066] Comparative Example 4 is the same as Example 1, except that the HCl solution is replaced with deionized water.

[0067] The sensor materials prepared in Comparative Examples 1-4 are tested according to the electrolyte corrosion test described above. The results show that, compared with the sensor material prepared in Example 1, the response of the sensor material of Comparative Example 1 to 50 ppm and 100 ppm is reduced to 32.6% and 38.1%, respectively, and the reduction is relatively large, indicating that a too high activation temperature can reduce the electrolyte corrosion resistance of the sensor material; the response of the sensor material of Comparative Example 2 to 50 ppm and 100 ppm is reduced to 50.3% and 61.5%, respectively, and the reduction is relatively large, indicating that activation treatment of the sensor material can help to improve its electrolyte corrosion resistance; the response of the sensor material of Comparative Example 3 to 50 ppm and 100 ppm is reduced to 14.3% and 15.0%, respectively, indicating that too much aniline monomer can negatively affect the electrolyte corrosion resistance of the sensor material; and the response of the sensor material of Comparative Example 4 to 50 ppm and 100 ppm is reduced to 28.4% and 33.7%, respectively, indicating that whether or not to dope a proton acid can significantly affect the electrolyte corrosion resistance of the sensor material.

[0068] The above description is merely preferred embodiments of the present application, but not to limit the present application. Any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall fall within the scope of the present application.

Claims

1. A method for preparing a tin dioxide / polyaniline composite nanometer carbon monoxide sensor material, characterized in that, The method comprises the following steps: A. Dissolving a tin salt in deionized water, then adding a NaOH solution, stirring and precipitating, transferring the precipitate solution to an autoclave for hydrothermal treatment, and cooling to room temperature, centrifuging to obtain the precipitate, then washing, drying, and grinding into powder to obtain tin oxide; wherein the tin salt is stannous chloride; B. Dissolving an aniline monomer and tin oxide in an acid solution, then adding an acid solution containing ammonium persulfate, and reacting under ice bath conditions, centrifuging to obtain a precipitate, washing, drying, and grinding into powder to obtain a composite; wherein the acid solution is a hydrochloric acid solution, the mass ratio of the aniline monomer to tin oxide is 1-20:100, and the molar ratio of ammonium persulfate to aniline is 1:1; C. Placing the composite in a porcelain boat, activating and treating with a tube furnace at 200-550℃ for 1-5h, and naturally cooling to room temperature to obtain a SnO2 / PANI composite material with a MOF metal organic framework structure.

2. The preparation method of the tin dioxide / polyaniline composite nano carbon monoxide sensor material as described in claim 1, characterized in that, The molar ratio of the tin salt to NaOH is 1:1-3.

3. The method of claim 1, wherein the tin dioxide / polyaniline composite nanometer carbon monoxide sensor material is prepared by the steps of: (a) mixing a tin dioxide powder and a polyaniline powder in a solvent to form a mixture; (b) adding a dispersant to the mixture; (c) stirring the mixture; (d) drying the mixture; and (e) calcining the mixture. In step A, the tin salt is dissolved in deionized water to obtain a tin salt solution, ultrasonic treatment is performed for 30-60min, and then a NaOH solution is added under magnetic stirring at a stirring speed of 450-600r / min.

4. The method of claim 1, wherein the tin dioxide / polyaniline composite nanometer carbon monoxide sensor material is prepared by the steps of: (a) mixing a tin dioxide powder and a polyaniline powder in a solvent to form a mixture; (b) adding a dispersant to the mixture; (c) stirring the mixture; (d) drying the mixture; and (e) calcining the mixture. In step A, the hydrothermal treatment conditions of the autoclave are 150-200℃, and the hydrothermal treatment time is 2-6h.

5. The method of claim 1, wherein the tin dioxide / polyaniline composite nanometer carbon monoxide sensor material is prepared by the steps of: (a) mixing a tin dioxide powder with a polyaniline solution; (b) stirring the mixture; (c) drying the mixture; (d) calcining the dried mixture; and (e) washing the calcined mixture with distilled water. In step A, the centrifugation speed is 8000-10000r / min.

6. The method of claim 1, wherein the tin dioxide / polyaniline composite nanometer carbon monoxide sensor material is prepared by the steps of: (a) mixing a tin dioxide powder with a polyaniline solution; (b) stirring the mixture; (c) drying the mixture; (d) calcining the dried mixture; and (e) washing the calcined mixture with distilled water. In step B, the ice bath temperature is 0-5℃, and the ice bath time is 6-8h.

7. A tin dioxide / polyaniline composite nanocarbon monoxide sensor material, characterized by, The sensor material is prepared by the preparation method of any one of claims 1-6.

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