Preparation method and application of high-sensitivity methane sensitive material

Abstract

The invention discloses preparation and application of a high-sensitivity methane sensitive material, which comprises the following steps: dissolving tin tetrachloride pentahydrate in a mixed solvent of glycerol, deionized water and isopropanol, stirring, adding urotropine, stirring, adding cerous nitrate, placing the obtained mixture in a reaction kettle for hydrothermal reaction 1, naturally cooling to room temperature, adding a catalyst, stirring, and carrying out vacuum drying to obtain the high-sensitivity methane sensitive material. Centrifugally washing to obtain a sample A; the sample A is pretreated with plasma and then modified with Pt, and the methane-sensitive gas-sensitive material is obtained. By means of co-doping of Ce and Pt, efficient adsorption and catalytic reaction of methane gas can be achieved, and high-sensitivity and specific detection of methane is achieved. The preparation method is simple, and the stability of a gas sensor in a long-term working state can be improved when the gas sensor is manufactured into an MEMS device.

Description

Technical Field

[0001] The invention relates to the field of gas detection, and in particular to a preparation method of a high-sensitivity methane sensitive material and application thereof. Background Art

[0002] Methane is a colorless, flammable, non-toxic, inflammable and explosive gas. The latest research shows that methane is one of the early volatile gases in thermal runaway of lithium-ion batteries. By detecting methane gas, early warning of lithium-ion thermal runaway can be given.

[0003] Metal oxide semiconductors are the preferred materials for gas sensors because they have excellent gas-sensing properties and their gas-sensitive response characteristics can be adjusted through morphology control, crystal type control, surface doping, and modification. In view of the special detection environment and requirements of methane gas, highly sensitive, ultrafast, and specific detection of methane gas can be achieved through material control.

[0004] The present invention provides a simple MEMS gas sensor based on SnO2 nanomaterials. By preparing SnO2 nanomaterials, regulating the pore structure and co-modifying CeO2 and Pt, it is helpful to achieve preferential adsorption and catalytic reaction of methane gas, so that the gas selectivity of the material can be greatly improved. The combination of semiconductor materials and MEMS devices can make use of the miniaturization, easy integration and good stability of MEMS devices, greatly improve the gas-sensitive performance of nanomaterials, especially selectivity and long-term stability. The preparation process is simple and the preparation cost is low, which has practical application value for further promoting the development of semiconductor gas-sensitive devices. Summary of the invention

[0005] The purpose of the present invention is to provide a method for preparing a methane gas sensitive material, which can improve the functionality of traditional materials.

[0006] Another object of the present invention is to provide an application of a methane gas sensitive material prepared by any of the above methods.

[0007] The object of the present invention is achieved by the following scheme: A method for preparing a highly sensitive methane sensitive material comprises the following steps: Step 1: dissolving tin tetrachloride pentahydrate in a mixed solvent of glycerol, deionized water and isopropanol, stirring for 30-40 min, adding urotropine, continuing to stir for 20-30 min, adding cerium nitrate according to the molar ratio of cerium nitrate to tin tetrachloride pentahydrate of 0.1-0.5:100, and then placing the obtained mixture in a reactor, hydrothermally reacting at 90-130 ° C for 12-20 hours, cooling naturally to room temperature, centrifuging, washing the precipitate with deionized water and ethanol respectively, and then placing it in an oven and drying it at 60 ° C. After grinding the dried powder, sample A is obtained; The mixed solvent is glycerol, deionized water and isopropanol, and the volume ratio of the three is 8-10:25-35:25-35; the concentration of tin tetrachloride pentahydrate in the final mixed solvent is 0.5-2 mmol / ml; The molar ratio of tin tetrachloride pentahydrate to hexamethylenetetramine is 1:4-6; Step 2: Take an appropriate amount of sample A obtained in step 1, pre-treat it with plasma, then immerse it in a HPtCl3·6H2O aqueous solution, and then freeze-dry it at -80°C. After immersing the dried powder in ascorbic acid for 20 min, centrifuge and dry it to obtain a methane-sensitive gas-sensitive material; The mass ratio of HPtCl3·6H2O to sample A is 0.2~0.8:10, and the concentration of HPtCl3·6H2O is 0.1~0.2mmol / ml; The present invention provides an application of a high-sensitivity methane sensitive material prepared by any of the above methods in preparing a methane-sensitive MEMS gas sensor. The preparation process of the device is as follows: take 0.1 g of gas-sensitive material, mix it with 1 mL of deionized water, add 1-2 drops of pine alcohol, and grind it clockwise in a mortar for 30 minutes to obtain a slurry; take a MEMS device with Pt interdigitated electrodes, ultrasonically clean it with deionized water and ethanol, blow it dry with a nitrogen gun, and evenly apply the obtained slurry on the surface of the MEMS device. After drying, place it in a muffle furnace for heat treatment at a temperature of 400-430 °C, a holding time of 1-2 h, and a heating rate of 1 °C / min. After the cavity cools to room temperature, take it out to obtain a methane-sensitive MEMS gas sensor.

[0008] The present invention utilizes Ce and Pt co-doping to achieve efficient adsorption and catalytic reaction of methane gas, and to achieve highly sensitive and specific detection of methane. The preparation method is simple, and the preparation method can be used to make a MEMS device, which can increase the stability of the gas sensor in a long-term working state. DETAILED DESCRIPTION Example

[0009] A highly sensitive methane sensitive material is prepared according to the following steps: Step 1: dissolving tin tetrachloride pentahydrate in a mixed solvent of glycerol, deionized water and isopropanol, wherein the volume ratio of glycerol, deionized water and isopropanol in the mixed solvent is 8:25:25, until the concentration of tin tetrachloride pentahydrate in the mixed solvent is 0.8 mmol / ml, stirring for 30 min, adding urotropine, the molar ratio of tin tetrachloride pentahydrate to urotropine is 1:6, stirring for 30 min, adding cerium nitrate according to the molar ratio of cerium nitrate to tin tetrachloride pentahydrate of 0.1:100, placing the resulting mixture in a reactor, hydrothermally reacting at 100°C for 18 hours, cooling naturally to room temperature, centrifuging, washing the precipitate with deionized water and ethanol respectively, and then placing it in an oven and drying it at 60°C, grinding the dried powder to obtain sample A; Step 2: Take an appropriate amount of sample A obtained in step 1, pre-treat it with plasma, immerse it in a 0.2 mmol / ml HPtCl3·6H2O aqueous solution until the mass ratio of HPtCl3·6H2O to sample A is 0.2:10, freeze-dry it at -80°C, immerse the freeze-dried powder in ascorbic acid for 20 min, and centrifuge it to obtain a methane-sensitive gas-sensitive material.

[0010] The preparation process of the gas sensor is: Take 0.1 g of gas-sensitive material, mix it with 1 mL of deionized water, add 1-2 drops of pine alcohol, and grind it clockwise in a mortar for 30 minutes to obtain a slurry; take a MEMS device with Pt interdigitated electrodes, ultrasonically clean it with deionized water and ethanol, blow it dry with a nitrogen gun, and evenly apply the obtained slurry on the surface of the MEMS device. After drying, place it in a muffle furnace for heat treatment at a temperature of 400 °C, a holding time of 2 h, and a heating rate of 1 °C / min. After the cavity cools to room temperature, take it out to obtain a methane-sensitive MEMS gas sensor.

[0011] The gas sensor prepared in this embodiment has an optimal response temperature of 280° C. to methane, a response time of 1.5 s to a concentration of 1 ppm, and a response value of 14.8. Example 2

[0012] A highly sensitive methane sensitive material is prepared in the following steps similar to those in Example 1: Step 1: dissolving tin tetrachloride pentahydrate in a mixed solvent of glycerol, deionized water and isopropanol, wherein the volume ratio of glycerol, deionized water and isopropanol in the mixed solvent is 8:30:35, and the concentration of tin tetrachloride pentahydrate in the final mixed solvent is 2.0 mmol / ml. After stirring for 30 min, urotropine is added, and the molar ratio of tin tetrachloride pentahydrate to urotropine is 1:4. After continuing to stir for 30 min, cerium nitrate is added according to the molar ratio of cerium nitrate to tin tetrachloride pentahydrate of 0.4:100, and the resulting mixture is placed in a reactor, subjected to hydrothermal reaction at 120°C for 18 hours, cooled naturally to room temperature, centrifuged, and the precipitate is washed with deionized water and ethanol respectively, and then placed in an oven and dried at 60°C. The dried powder is ground to obtain sample A; Step 2: Take an appropriate amount of sample A obtained in step 1, pre-treat it with plasma, and then immerse it in a 0.1 mmol / ml HPtCl3·6H2O aqueous solution, the mass ratio of HPtCl3·6H2O to sample A is 0.6:10, and then freeze-dry it at -80 °C. After immersing the dried powder in ascorbic acid for 20 min, centrifuge and dry it to obtain a methane-sensitive gas-sensitive material.

[0013] The preparation process of methane sensitive MEMS gas sensor is: Take 0.1 g of gas-sensitive material, mix it with 1 mL of deionized water, add 1-2 drops of pine alcohol, and grind it clockwise in a mortar for 30 minutes to obtain a slurry; take a MEMS device with Pt interdigitated electrodes, ultrasonically clean it with deionized water and ethanol, blow it dry with a nitrogen gun, and evenly apply the obtained slurry on the surface of the MEMS device. After drying, place it in a muffle furnace for heat treatment at a temperature of 430 °C, a holding time of 2 h, and a heating rate of 1 °C / min. After the cavity cools to room temperature, take it out to obtain a methane-sensitive MEMS gas sensor.

[0014] The gas sensor prepared in this embodiment has an optimal response temperature of 280° C. to methane, a response time of 1.6 s to a concentration of 1 ppm, and a response value of 15.3. Example 3

[0015] A highly sensitive methane sensitive material is prepared in the following steps similar to those in Example 1: Step 1: dissolving tin tetrachloride pentahydrate in a mixed solvent of glycerol, deionized water and isopropanol, wherein the volume ratio of glycerol, deionized water and isopropanol in the mixed solvent is 8:35:35, and the concentration of tin tetrachloride pentahydrate in the final mixed solvent is 2 mmol / ml. After stirring for 30 min, urotropine is added, and the molar ratio of tin tetrachloride pentahydrate to urotropine is 1:5. After continuing to stir for 30 min, cerium nitrate is added according to the molar ratio of cerium nitrate to tin tetrachloride pentahydrate of 0.2:100, and then the obtained mixture is placed in a reactor, and hydrothermally reacted at 100 ° C for 24 hours. After naturally cooling to room temperature, centrifugation is performed, and the precipitate is washed with deionized water and ethanol respectively, and then placed in an oven and dried at 60 ° C. The dried powder is ground to obtain sample A; Step 2: Take an appropriate amount of sample A obtained in step 1, pre-treat it with plasma, and then immerse it in a 0.1 mmol / ml HPtCl3·6H2O aqueous solution until the mass ratio of HPtCl3·6H2O to sample A is 0.8:10, and then freeze-dry it at -80°C. After immersing the dried powder in ascorbic acid for 20 min, centrifuge and dry it to obtain a methane-sensitive gas-sensitive material.

[0016] The preparation process of methane sensitive MEMS gas sensor is: Take 0.1 g of gas-sensitive material, mix it with 1 mL of deionized water, add 1-2 drops of pine alcohol, and grind it clockwise in a mortar for 30 minutes to obtain a slurry; take a MEMS device with Pt interdigitated electrodes, ultrasonically clean it with deionized water and ethanol, blow it dry with a nitrogen gun, and evenly apply the obtained slurry on the surface of the MEMS device. After drying, place it in a muffle furnace for heat treatment at a temperature of 430 °C, a holding time of 1 h, and a heating rate of 1 °C / min. After the cavity cools to room temperature, take it out to obtain a methane-sensitive MEMS gas sensor.

[0017] The gas sensor manufactured in this embodiment has an optimal response temperature of 280° C. to methane, a response time of 1.3 s to a concentration of 1 ppm, and a response value of 14.2.

Claims

1. A method for preparing a highly sensitive methane sensitive material, characterized in that: The steps include: Step 1: dissolving tin tetrachloride pentahydrate in a mixed solvent of glycerol, deionized water and isopropanol until the concentration of tin tetrachloride pentahydrate in the mixed solvent is 0.5-2 mmol / ml, stirring for 30-40 min, adding urotropine, continuing to stir for 20-30 min, adding cerium nitrate according to the molar ratio of cerium nitrate to tin tetrachloride pentahydrate of 0.1-0.5:100, placing the resulting mixture in a reactor, hydrothermally reacting at 90-130 °C for 12-20 hours, cooling naturally to room temperature, centrifuging, washing the precipitate with deionized water and ethanol respectively, and then placing it in an oven and drying it at 60 °C. Grinding the dried powder to obtain sample A; Step 2: Take sample A obtained in step 1, pre-treat it with plasma, immerse it in a HPtCl3·6H2O aqueous solution until the mass ratio of HPtCl3·6H2O to sample A is 0.2~0.8:10, freeze-dry it at -80°C, immerse the freeze-dried powder in ascorbic acid for 20 min, and centrifuge and dry it to obtain a methane-sensitive gas-sensitive material.

2. The method for preparing a highly sensitive methane sensitive material according to claim 1, characterized in that: In step 1, the volume ratio of propylene glycol, deionized water and isopropanol in the mixed solvent is 8-10:25-35:25-35.

3. The method for preparing a highly sensitive methane sensitive material according to claim 1, characterized in that: The molar ratio of tin tetrachloride pentahydrate to hexamethylenetetramine is 1:4-6.

4. The method for preparing a highly sensitive methane sensitive material according to claim 1, characterized in that: The concentration of the HPtCl3·6H2O is 0.1-0.2 mmol / ml.

5. The method for preparing a highly sensitive methane sensitive material according to any one of claims 1 to 4, characterized in that: Prepare as follows: Step 1: dissolving tin tetrachloride pentahydrate in a mixed solvent of glycerol, deionized water and isopropanol, wherein the volume ratio of glycerol, deionized water and isopropanol in the mixed solvent is 8:25:25, until the concentration of tin tetrachloride pentahydrate in the mixed solvent is 0.8 mmol / ml, stirring for 30 min, adding urotropine, the molar ratio of tin tetrachloride pentahydrate to urotropine is 1:6, stirring for 30 min, adding cerium nitrate according to the molar ratio of cerium nitrate to tin tetrachloride pentahydrate of 0.1:100, placing the resulting mixture in a reactor, hydrothermally reacting at 100°C for 18 hours, cooling naturally to room temperature, centrifuging, washing the precipitate with deionized water and ethanol respectively, and then placing it in an oven and drying it at 60°C, grinding the dried powder to obtain sample A; Step 2: Take an appropriate amount of sample A obtained in step 1, pre-treat it with plasma, immerse it in a 0.2 mmol / ml HPtCl3·6H2O aqueous solution until the mass ratio of HPtCl3·6H2O to sample A is 0.2:10, freeze-dry it at -80°C, immerse the freeze-dried powder in ascorbic acid for 20 min, and centrifuge it to obtain a methane-sensitive gas-sensitive material.

6. The method for preparing a highly sensitive methane sensitive material according to any one of claims 1 to 4, characterized in that: Prepare as follows: Step 1: dissolving tin tetrachloride pentahydrate in a mixed solvent of glycerol, deionized water and isopropanol, wherein the volume ratio of glycerol, deionized water and isopropanol in the mixed solvent is 8:30:35, and the concentration of tin tetrachloride pentahydrate in the final mixed solvent is 2.0 mmol / ml. After stirring for 30 min, urotropine is added, and the molar ratio of tin tetrachloride pentahydrate to urotropine is 1:

4. After continuing to stir for 30 min, cerium nitrate is added according to the molar ratio of cerium nitrate to tin tetrachloride pentahydrate of 0.4:100, and the resulting mixture is placed in a reactor, subjected to hydrothermal reaction at 120°C for 18 hours, cooled naturally to room temperature, centrifuged, and the precipitate is washed with deionized water and ethanol respectively, and then placed in an oven and dried at 60°C. The dried powder is ground to obtain sample A; Step 2: Take an appropriate amount of sample A obtained in step 1, pre-treat it with plasma, and then immerse it in a 0.1 mmol / ml HPtCl3·6H2O aqueous solution, the mass ratio of HPtCl3·6H2O to sample A is 0.6:10, and then freeze-dry it at -80 °C. After immersing the dried powder in ascorbic acid for 20 min, centrifuge and dry it to obtain a methane-sensitive gas-sensitive material.

7. The method for preparing a highly sensitive methane sensitive material according to any one of claims 1 to 4, characterized in that: Prepare as follows: Step 1: dissolving tin tetrachloride pentahydrate in a mixed solvent of glycerol, deionized water and isopropanol, wherein the volume ratio of glycerol, deionized water and isopropanol in the mixed solvent is 8:35:35, and the concentration of tin tetrachloride pentahydrate in the final mixed solvent is 2 mmol / ml. After stirring for 30 min, urotropine is added, and the molar ratio of tin tetrachloride pentahydrate to urotropine is 1:

5. After continuing to stir for 30 min, cerium nitrate is added according to the molar ratio of cerium nitrate to tin tetrachloride pentahydrate of 0.2:100, and then the obtained mixture is placed in a reactor, and hydrothermally reacted at 100 ° C for 24 hours. After naturally cooling to room temperature, centrifugation is performed, and the precipitate is washed with deionized water and ethanol respectively, and then placed in an oven and dried at 60 ° C. The dried powder is ground to obtain sample A; Step 2: Take an appropriate amount of sample A obtained in step 1, pre-treat it with plasma, and then immerse it in a 0.1 mmol / ml HPtCl3·6H2O aqueous solution until the mass ratio of HPtCl3·6H2O to sample A is 0.8:10, and then freeze-dry it at -80°C. After immersing the dried powder in ascorbic acid for 20 min, centrifuge and dry it to obtain a methane-sensitive gas-sensitive material.

8. A high-sensitivity methane sensitive material prepared according to any one of claims 1-7.

9. Application of a high-sensitivity methane sensitive material in the preparation of methane-sensitive MEMS gas sensors.

10. A methane-sensitive MEMS gas sensor, characterized in that: Prepare as follows: Take 0.1 g of gas-sensitive material, mix it with 1 mL of deionized water, add 1-2 drops of pine alcohol, and grind it clockwise in a mortar for 30 minutes to obtain a slurry; take a MEMS device with Pt interdigitated electrodes, ultrasonically clean it with deionized water and ethanol, blow it dry with a nitrogen gun, and evenly apply the obtained slurry on the surface of the MEMS device. After drying, place it in a muffle furnace for heat treatment at a temperature of 400-430 °C, a holding time of 1-2 h, and a heating rate of 1 °C / min. After the cavity cools to room temperature, take it out to obtain a methane-sensitive MEMS gas sensor.