Acetone sensor based on metal ion-doped ceria aerogel, preparation method and application in acetone detection

Abstract

An acetone sensor based on metal ion-doped ceria aerogel, a preparation method, and its application in acetone detection belong to the field of gas sensor technology. The sensor comprises an Al2O3 ceramic tube substrate, two parallel and separate annular Au electrodes coated on the outer surface of the Al2O3 ceramic tube substrate, a gas-sensitive film coated on the outer surface of the Al2O3 ceramic tube and on the annular Au electrodes, and a nickel-chromium alloy heating coil passing through the interior of the Al2O3 ceramic tube. The gas-sensitive film is made of a porous metal ion-doped ceria aerogel, where the metal ions are cobalt, copper, manganese, etc. This rich porous structure helps increase the number of surface active sites on the material and enhances the diffusion rate of gas molecules and reaction products. The sensor based on metal ion-doped ceria aerogel prepared by the present invention has an ultrafast response recovery rate to acetone and has good application prospects.

Description

Technical Field

[0001] The present invention belongs to the technical field of gas sensors, and in particular relates to an acetone sensor based on metal ion-doped ceria aerogel, a preparation method and application of the sensor in acetone detection. Background Art

[0002] Acetone, a commonly used organic chemical reagent, is an indispensable solvent or key raw material in fields such as organic chemical synthesis and chemical production. However, acetone is highly volatile and can spread and diffuse in the atmosphere. Once acetone gas enters the human body, it poses serious health risks. Therefore, acetone has become a typical toxic and harmful gas. Furthermore, acetone gas is a unique gas found in exhaled breath, with its concentration varying depending on health status. For example, the exhaled acetone concentration in healthy individuals is approximately 0.3 to 0.9 ppm, while that in diabetic patients is generally greater than 1.8 ppm. Therefore, measuring exhaled acetone concentration offers a new approach for noninvasively diagnosing diabetes. As discussed above, accurately measuring the concentration of acetone gas in the atmosphere has significant research significance and practical value in fields such as environmental monitoring and medical diagnosis.

[0003] In recent years, resistive gas sensors based on semiconductor oxides have garnered widespread attention from both academia and industry. Due to their low cost, simple structure, and ease of device integration, they have become a rapidly developing gas detection technology, promising to overcome bottlenecks in traditional analytical instruments, such as bulk, complex operation, and the inability to perform online detection. Ceria, a typical n-type semiconductor material, is a highly effective catalyst or catalyst support in catalysis. Generally speaking, the sensitivity of a gas sensor depends on the redox reaction between the target gas molecules and the sensitive material. Therefore, ceria materials with excellent catalytic properties hold potential for application in the field of gas sensors. However, current preparation methods for ceria materials still suffer from complex procedures and low yields. Furthermore, the gas sensitivity performance of ceria materials needs to be further improved. Therefore, developing simple and efficient preparation techniques and improving the sensitivity of ceria materials are critical issues that urgently need to be addressed. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the present invention aims to improve the gas-sensing performance of ceria to acetone by utilizing the rich void structure of aerogel materials and the doping effect of metal ions, thereby providing an acetone sensor based on metal ion-doped ceria aerogel, a preparation method, and its application in acetone detection, in order to solve the problems existing in the background technology.

[0005] The present invention discloses an acetone sensor based on metal ion-doped ceria aerogel, which has a ceramic tube structure and comprises an Al2O3 ceramic tube substrate, two parallel and separate annular Au electrodes coated on the outer surface of the Al2O3 ceramic tube substrate, a gas-sensitive film coated on the outer surface of the Al2O3 ceramic tube and the annular Au electrodes, and a nickel-chromium alloy heating coil passing through the interior of the Al2O3 ceramic tube. The gas-sensitive film is made of metal ion-doped ceria aerogel and is prepared in the following steps:

[0006] (1) adding 0.5-1.0 g of ammonium cerium nitrate powder to 1.0-5.0 mL of water and stirring at room temperature for 5-10 minutes to obtain an aqueous solution of ammonium cerium nitrate;

[0007] (2) adding 0.25-1.0 g of glucose to the aqueous solution of ammonium cerium nitrate obtained in step (1), stirring at room temperature for 5-10 min to obtain a mixed aqueous solution of ammonium cerium nitrate and glucose;

[0008] (3) adding 1.0-3.0 mL of a metal nitrate aqueous solution (manganese nitrate, copper nitrate, cobalt nitrate, etc.) at a concentration of 2.0-5.0 mg / mL to the mixed aqueous solution of ammonium cerium nitrate and glucose obtained in step (2), and stirring at room temperature for 5-10 minutes to obtain a mixed aqueous solution of metal nitrate, ammonium cerium nitrate, and glucose;

[0009] (4) placing the mixed aqueous solution of metal nitrate, ammonium cerium nitrate and glucose obtained in step (3) in a constant temperature drying oven and drying it at 100-120° C. for 30-50 min to obtain a solid mixture of metal nitrate, ammonium cerium nitrate and glucose;

[0010] (5) calcining the solid mixture of metal nitrate, ammonium cerium nitrate and glucose obtained in step (4) at 500-600° C. for 2-4 hours to obtain the metal ion-doped ceria aerogel.

[0011] The Al2O3 ceramic tube used in the present invention has a length of 3 to 5 mm, an outer diameter of 1.1 to 1.3 mm, and an inner diameter of 0.7 to 0.9 mm. The nickel-chromium alloy heating coil provides a suitable operating temperature for the sensor, and the resistance of the heating coil is 30 to 40 Ω. The width of the annular Au electrode is 0.7 to 0.9 mm, the spacing between the two Au electrodes is 1.7 to 1.9 mm, the thickness of the Au electrode is 0.05 to 0.08 mm, and the thickness of the gas-sensitive film is 180 to 220 μm. The resistance of the gas-sensitive film changes before and after contact with the gas to be measured. The sensitivity of the sensor can be obtained by measuring the change in resistance between the two annular Au electrodes. The sensitivity is calculated by dividing the resistance of the two annular Au electrodes in air by their resistance in the target gas.

[0012] The method for preparing a resistive acetone sensor based on metal ion-doped ceria aerogel according to the present invention comprises the following steps:

[0013] (1) mixing metal ion-doped ceria aerogel with deionized water in a mass ratio of 3 to 5:1 and grinding the mixture into a paste-like slurry; coating the paste onto the surface of an Al2O3 ceramic tube having two parallel and separate annular Au electrodes on its outer surface;

[0014] (2) baking the device obtained in step (1) under an infrared lamp for 20 to 40 minutes. After the sensitive material is dried, a nickel-chromium alloy heating coil with a resistance value of 30 to 40 Ω is passed through the interior of the Al2O3 ceramic tube as a heating wire, and then welded and packaged as a indirectly heated gas sensor.

[0015] (3) The device obtained in step (2) is aged at 280-320° C. for 8-12 hours to obtain the resistive acetone sensor based on metal ion-doped ceria aerogel.

[0016] The advantages of the present invention are:

[0017] 1) The metal ion-doped ceria aerogel of the present invention has a porous structure. The rich porous structure is beneficial to increasing the number of surface active sites of the material and improving the diffusion rate of gas molecules and reaction products;

[0018] 2) The metal ion-doped ceria aerogel of the present invention has good crystallinity, which makes the material have excellent stability;

[0019] 3) In the present invention, the gas generated by the thermal decomposition of precursors such as nitrate, ammonium cerium nitrate, and glucose is used as a template to prepare a metal ion-doped ceria aerogel with a porous structure, without the need to use expensive organic compounds as templates;

[0020] 4) The present invention adopts a direct calcination method to prepare metal ion-doped ceria aerogel, which is simple, efficient, high in yield, and suitable for mass production;

[0021] 5) The sensor based on metal ion-doped ceria aerogel prepared in the present invention has an ultrafast response recovery rate to acetone and has good application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is a scanning electron microscope photograph of the cobalt-doped ceria aerogel prepared in Example 1;

[0023] Figure 2 1. The nitrogen adsorption curve (a) and pore distribution curve (b) of the cobalt-doped ceria aerogel prepared in Example 1;

[0024] Figure 3 is the X-ray diffraction pattern of the cobalt-doped ceria aerogel prepared in Example 2;

[0025] Figure 4 is the X-ray diffraction pattern of the copper-doped ceria aerogel prepared in Example 3;

[0026] Figure 5 is the X-ray diffraction pattern of the manganese-doped ceria aerogel prepared in Example 5;

[0027] Figure 6 5 is the response recovery curve of the acetone sensor based on cobalt-doped ceria aerogel prepared in Example 2 to 500 ppm acetone at 290°C;

[0028] Figure 7 3 is the response recovery curve of the acetone sensor based on copper-doped ceria aerogel prepared in Example 3 to 500 ppm acetone at 290°C;

[0029] Figure 8 This is the response recovery curve of the acetone sensor based on manganese-doped ceria aerogel prepared in Example 5 to 500 ppm acetone at 290°C.

[0030] Figure 9 1 is the response recovery curve of the acetone sensor based on cobalt-doped ceria aerogel prepared in Example 2 to 100-600 ppm acetone at 290° C.;

[0031] Figure 10 These are six consecutive response recovery curves of the acetone sensor based on cobalt-doped ceria aerogel prepared in Example 2 to 500 ppm acetone at 290°C.

[0032] The scanning electron microscope photo of the cobalt-doped cerium dioxide aerogel prepared in Example 1 is as follows: Figure 1 As shown, the cobalt-doped ceria aerogel is composed of a typical lamellar structure. Numerous voids exist between the lamellar layers, forming the aerogel structure. Furthermore, numerous pores are distributed within the plane of the cobalt-doped ceria lamellar structure, demonstrating that the cobalt-doped ceria aerogel prepared by the present invention possesses a unique porous structure.

[0033] The nitrogen adsorption-desorption curve and pore distribution curve of the cobalt-doped ceria aerogel prepared in Example 1 are shown in FIG. Figure 2 As shown in Figure 2, the cobalt-doped ceria aerogel exhibits obvious adsorption behavior in the high pressure region, indicating a porous structure. The pore distribution curve further illustrates the presence of mesoporous structures with a size of 2 to 10 nm in the cobalt-doped ceria aerogel.

[0034] The X-ray diffraction pattern of the cobalt-doped cerium dioxide aerogel prepared in Example 2 is as follows: Figure 3 As shown in the figure, it can be seen that the cobalt-doped ceria aerogel gives eight obvious peaks at 28.55°, 33.09°, 47.53°, 56.34°, 59.15°, 69.49°, 76.77°, and 79.06°. These peaks are attributed to the characteristic crystal diffraction peaks of ceria. In addition, the intensity of these diffraction peaks is high and the peaks are narrow, indicating that the prepared cobalt-doped ceria aerogel has good crystallinity. Figure 3 No diffraction peak belonging to cobalt oxide was observed, indicating that the cobalt element was doped into the cerium dioxide lattice in the form of ions.

[0035] The X-ray diffraction pattern of the copper-doped cerium dioxide aerogel prepared in Example 3 is as follows: Figure 4 As shown in the figure, it can be seen that the copper-doped ceria aerogel has the same crystal structure as ceria and maintains good crystallinity, indicating that the doping of copper ions has not changed the crystal structure of ceria. Since copper ions are distributed in the ceria lattice in the form of ion doping, no diffraction peaks attributable to metallic copper or copper oxide are observed.

[0036] The X-ray diffraction pattern of the manganese-doped cerium dioxide aerogel prepared in Example 5 is as follows: Figure 5 As shown in the figure, it can be seen that the manganese-doped ceria aerogel also maintains a good crystal structure that is the same as that of ceria; in addition, Figure 5 No diffraction peaks belonging to manganese element and manganese oxide were observed, which is because manganese ions are uniformly doped into the lattice of ceria.

[0037] The response recovery transient curve of the acetone gas sensor based on cobalt-doped ceria aerogel prepared in Example 2 to 500 ppm acetone at 290°C is shown in FIG. Figure 6 It can be seen that the sensor has good response and recovery characteristics to acetone, and has a fast response and recovery rate, with a response time of 5.5s.

[0038] Recovery time is 12.5s;

[0039] The response recovery transient curve of the acetone gas sensor based on copper-doped ceria aerogel prepared in Example 3 to 500 ppm acetone at 290°C is shown in FIG. Figure 7 As shown in the figure, the sensor also exhibits fast response and recovery characteristics to acetone, with a response time of 37.1s and a recovery time of 21.5s.

[0040] The response recovery transient curve of the acetone gas sensor based on manganese-doped ceria aerogel prepared in Example 5 to 500 ppm acetone at 290°C is shown in FIG. Figure 8As shown in the figure, the sensor exhibits good response recovery characteristics to acetone, with a response time of 17.1s and a recovery time of 12.5s.

[0041] The dynamic resistance response curve of the acetone sensor based on cobalt-doped ceria aerogel prepared in Example 2 to 100-600 ppm acetone at 290°C is shown in FIG. Figure 9 It can be seen that with the increase of acetone concentration, the response value of the sensor gradually increases. At the same time, the sensor has fast response and recovery characteristics to different concentrations of acetone, and the detection limit of acetone is 100ppm.

[0042] The response repeatability curve of the acetone sensor based on cobalt-doped ceria aerogel prepared in Example 2 to 500 ppm acetone at 290°C is shown in FIG. Figure 10 It can be seen that the cobalt-doped ceria aerogel-based sensor shows a stable and repetitive response when repeatedly exposed to 500 ppm acetone, indicating that the sensor has excellent reproducibility. DETAILED DESCRIPTION

[0043] The present invention is further described below with reference to the accompanying drawings and examples.

[0044] Example 1

[0045] (1) Add 0.5 g of ammonium cerium nitrate powder to 1.0 mL of water and stir at room temperature for 5 min to obtain an aqueous solution of ammonium cerium nitrate;

[0046] (2) adding 1.0 g of glucose to the aqueous solution of ammonium cerium nitrate obtained in step (1), stirring at room temperature for 5 min to obtain a mixed aqueous solution of ammonium cerium nitrate and glucose;

[0047] (3) adding 3.0 mL of a 2.0 mg / mL aqueous solution of cobalt nitrate to the mixed aqueous solution of ammonium cerium nitrate and glucose obtained in step (2), and stirring at room temperature for 5 min to obtain a mixed aqueous solution of cobalt nitrate, ammonium cerium nitrate and glucose;

[0048] (4) placing the mixed aqueous solution of cobalt nitrate, ammonium cerium nitrate and glucose obtained in step (3) in a constant temperature drying oven and drying it at 100° C. for 50 min to obtain a solid mixture of cobalt nitrate, ammonium cerium nitrate and glucose;

[0049] (5) calcining the solid mixture of cobalt nitrate, cerium ammonium nitrate and glucose obtained in step (4) at 600° C. for 4 h to obtain a cobalt ion-doped cerium dioxide aerogel material with a product mass of 0.16 g;

[0050] (6) The cobalt ion-doped cerium dioxide aerogel material prepared in step (5) is mixed with deionized water in a mass ratio of 3:1 and ground into a paste slurry. The slurry is then applied to the surface of an Al2O3 ceramic tube with two parallel, annular and separate gold electrodes on the outer surface. The tube is baked under an infrared lamp for 20 minutes to obtain a sensitive film based on cobalt ion-doped cerium dioxide aerogel on the surface of the ceramic tube. The thickness of the sensitive film is 180 μm. A nickel-chromium alloy heating coil with a resistance value of 30 Ω is then passed through the Al2O3 ceramic tube as a heating wire. Finally, the tube is welded and packaged as a side-heated gas sensor. The length of the Al2O3 ceramic tube is 3 mm, the outer diameter is 1.1 mm, and the inner diameter is 0.7 mm. The width of the annular Au electrode is 0.7 mm, the distance between the two electrodes is 1.7 mm, and the thickness of the Au electrode is 0.05 mm.

[0051] (7) The acetone gas sensor based on the cobalt ion-doped ceria aerogel material obtained in step (6) is aged at 280° C. for 12 hours to complete the aging treatment of the gas sensor, thereby obtaining a resistive acetone sensor based on the cobalt ion-doped ceria aerogel material.

[0052] Example 2

[0053] (1) Add 0.6 g of ammonium cerium nitrate powder to 1.0 mL of water and stir at room temperature for 10 min to obtain an aqueous solution of ammonium cerium nitrate;

[0054] (2) adding 1.0 g of glucose to the aqueous solution of ammonium cerium nitrate obtained in step (1), stirring at room temperature for 5 min to obtain a mixed aqueous solution of ammonium cerium nitrate and glucose;

[0055] (3) adding 3.0 mL of a 2.0 mg / mL cobalt nitrate solution to the mixed aqueous solution of ammonium cerium nitrate and glucose obtained in step (2), and stirring at room temperature for 5 min to obtain a mixed aqueous solution of cobalt nitrate, ammonium cerium nitrate and glucose;

[0056] (4) placing the mixed aqueous solution of cobalt nitrate, ammonium cerium nitrate and glucose obtained in step (3) in a constant temperature drying oven and drying at 100° C. for 50 min to obtain a solid mixture of cobalt nitrate, ammonium cerium nitrate and glucose;

[0057] (5) calcining the solid mixture of cobalt nitrate, cerium ammonium nitrate and glucose obtained in step (4) at 600° C. for 3 h to obtain a cobalt ion-doped cerium dioxide aerogel material with a product mass of 0.19 g;

[0058] (6) The cobalt ion-doped cerium dioxide aerogel material prepared in step (5) is mixed with deionized water in a mass ratio of 3:1 and ground into a paste slurry. The slurry is then applied to the surface of an Al2O3 ceramic tube with two parallel, annular and separate gold electrodes on the outer surface. The tube is baked under an infrared lamp for 20 minutes to obtain a sensitive film based on cobalt ion-doped cerium dioxide aerogel on the surface of the ceramic tube. The thickness of the sensitive film is 180 μm. A nickel-chromium alloy heating coil with a resistance value of 30 Ω is then passed through the Al2O3 ceramic tube as a heating wire. Finally, the tube is welded and packaged as a side-heated gas sensor. The length of the Al2O3 ceramic tube is 3 mm, the outer diameter is 1.1 mm, and the inner diameter is 0.7 mm. The width of the annular Au electrode is 0.7 mm, the distance between the two electrodes is 1.7 mm, and the thickness of the Au electrode is 0.05 mm.

[0059] (7) The acetone gas sensor based on the cobalt ion-doped ceria aerogel material obtained in step (6) is aged at 280° C. for 12 hours to complete the aging treatment of the gas sensor, thereby obtaining a resistive acetone sensor based on the cobalt ion-doped ceria aerogel material.

[0060] Example 3

[0061] (1) Add 0.7 g of ammonium cerium nitrate powder to 3.0 mL of water and stir at room temperature for 5 min to obtain an aqueous solution of ammonium cerium nitrate;

[0062] (2) adding 0.5 g of glucose to the aqueous solution of ammonium cerium nitrate obtained in step (1), stirring at room temperature for 5 min to obtain a mixed aqueous solution of ammonium cerium nitrate and glucose;

[0063] (3) adding 2.0 mL of a 2.0 mg / mL copper nitrate solution to the mixed aqueous solution of ammonium cerium nitrate and glucose obtained in step (2), and stirring at room temperature for 5 min to obtain a mixed aqueous solution of copper nitrate, ammonium cerium nitrate and glucose;

[0064] (4) placing the mixed aqueous solution of copper nitrate, ammonium cerium nitrate and glucose obtained in step (3) in a constant temperature drying oven and drying at 110° C. for 40 min to obtain a solid mixture of copper nitrate, ammonium cerium nitrate and glucose;

[0065] (5) calcining the solid mixture of copper nitrate, ammonium cerium nitrate and glucose obtained in step (4) at 600° C. for 2 h to obtain a copper ion-doped cerium dioxide aerogel material with a product mass of 0.22 g;

[0066] (6) The copper ion-doped cerium dioxide aerogel material prepared in step (5) is mixed with deionized water in a mass ratio of 3:1 and ground into a paste slurry, which is then coated on the surface of an Al2O3 ceramic tube having two parallel, annular and separate gold electrodes on the outer surface; the mixture is baked under an infrared lamp for 20 minutes to obtain a sensitive film based on the copper ion-doped cerium dioxide aerogel on the surface of the ceramic tube, and the thickness of the sensitive film is 180 μm; a nickel-chromium alloy heating coil with a resistance value of 30 Ω is then passed through the Al2O3 ceramic tube as a heating wire, and finally welded and packaged according to the indirect heating type gas sensor; the Al2O3 ceramic tube has a length of 3 mm, an outer diameter of 1.1 mm, and an inner diameter of 0.7 mm; the width of the annular Au electrode is 0.7 mm, the distance between the two electrodes is 1.7 mm, and the thickness of the Au electrode is 0.06 mm;

[0067] (7) The acetone gas sensor of the copper metal ion-doped ceria aerogel material obtained in step (6) is aged at 280° C. for 12 hours to complete the aging treatment of the gas sensor, thereby obtaining a resistive acetone sensor based on the copper ion-doped ceria aerogel material.

[0068] Example 4

[0069] (1) Add 0.8 g of ammonium cerium nitrate powder to 3.0 mL of water and stir at room temperature for 10 min to obtain an aqueous solution of ammonium cerium nitrate;

[0070] (2) adding 0.5 g of glucose to the aqueous solution of ammonium cerium nitrate obtained in step (1), stirring at room temperature for 10 min to obtain a mixed aqueous solution of ammonium cerium nitrate and glucose;

[0071] (3) adding 2.0 mL of a 5.0 mg / mL copper nitrate solution to the mixed aqueous solution of ammonium cerium nitrate and glucose obtained in step (2), and stirring at room temperature for 10 min to obtain a mixed aqueous solution of copper nitrate, ammonium cerium nitrate and glucose;

[0072] (4) placing the mixed aqueous solution of copper nitrate, ammonium cerium nitrate and glucose obtained in step (3) in a constant temperature drying oven and drying at 110° C. for 40 min to obtain a solid mixture of copper nitrate, ammonium cerium nitrate and glucose;

[0073] (5) calcining the solid mixture of copper nitrate, ammonium cerium nitrate and glucose obtained in step (4) at 500° C. for 4 h to obtain a copper ion-doped cerium dioxide aerogel material with a product mass of 0.25 g;

[0074] (6) The copper ion-doped ceria aerogel material prepared in step (5) is mixed with deionized water in a mass ratio of 3:1 and ground into a paste slurry. The slurry is then applied to the surface of an Al2O3 ceramic tube with two parallel, annular, and separate gold electrodes on the outer surface. The tube is baked under an infrared lamp for 20 minutes to obtain a sensitive film based on copper ion-doped ceria aerogel on the surface of the ceramic tube. The thickness of the sensitive film is 180 μm. A nickel-chromium alloy heating coil with a resistance value of 30 Ω is then passed through the Al2O3 ceramic tube as a heating wire. Finally, the tube is welded and packaged as a side-heated gas sensor. The length of the Al2O3 ceramic tube is 3 mm, the outer diameter is 1.1 mm, and the inner diameter is 0.7 mm. The width of the annular Au electrode is 0.7 mm, the distance between the two electrodes is 1.7 mm, and the thickness of the Au electrode is 0.06 mm.

[0075] (7) The acetone gas sensor of the copper metal ion-doped ceria aerogel material obtained in step (6) is aged at 280° C. for 12 hours to complete the aging treatment of the gas sensor, thereby obtaining a resistive acetone sensor based on the copper ion-doped ceria aerogel material.

[0076] Example 5

[0077] (1) Add 0.9 g of ammonium cerium nitrate powder to 5.0 mL of water and stir at room temperature for 5 min to obtain an aqueous solution of ammonium cerium nitrate;

[0078] (2) adding 0.25 g of glucose to the aqueous solution of ammonium cerium nitrate obtained in step (1), stirring at room temperature for 10 min to obtain a mixed aqueous solution of ammonium cerium nitrate and glucose;

[0079] (3) adding 1.0 mL of a 2.0 mg / mL manganese nitrate solution to the mixed solution of ammonium cerium nitrate and glucose obtained in step (2), and stirring at room temperature for 10 min to obtain a mixed aqueous solution of manganese nitrate, ammonium cerium nitrate and glucose;

[0080] (4) placing the mixed aqueous solution of manganese nitrate, ammonium cerium nitrate and glucose obtained in step (3) in a constant temperature drying oven and drying at 120° C. for 30 min to obtain a solid mixture of manganese nitrate, ammonium cerium nitrate and glucose;

[0081] (5) calcining the solid mixture of manganese nitrate, cerium ammonium nitrate and glucose obtained in step (4) at 500° C. for 3 h to obtain a manganese ion-doped cerium dioxide aerogel material with a product mass of 0.28 g;

[0082] (6) The manganese ion-doped cerium dioxide aerogel material prepared in step (5) is mixed with deionized water in a mass ratio of 3:1 and ground into a paste slurry. The slurry is then applied to the surface of an Al2O3 ceramic tube with two parallel, annular and separate gold electrodes on the outer surface. The tube is baked under an infrared lamp for 20 minutes to obtain a sensitive film based on manganese ion-doped cerium dioxide aerogel on the surface of the ceramic tube. The thickness of the sensitive film is 180 μm. A nickel-chromium alloy heating coil with a resistance value of 30 Ω is then passed through the Al2O3 ceramic tube as a heating wire. Finally, the tube is welded and packaged as a side-heated gas sensor. The length of the Al2O3 ceramic tube is 3 mm, the outer diameter is 1.1 mm, and the inner diameter is 0.7 mm. The width of the annular Au electrode is 0.7 mm, the distance between the two electrodes is 1.7 mm, and the thickness of the Au electrode is 0.08 mm.

[0083] (7) The acetone gas sensor based on the manganese ion-doped ceria aerogel material obtained in step (6) is aged at 280° C. for 12 hours to complete the aging treatment of the gas sensor, thereby obtaining a resistive acetone sensor based on the manganese ion-doped ceria aerogel material.

[0084] Example 6

[0085] (1) Add 1.0 g of ammonium cerium nitrate powder to 5.0 mL of water and stir at room temperature for 10 min to obtain an aqueous solution of ammonium cerium nitrate;

[0086] (2) adding 0.25 g of glucose to the aqueous solution of ammonium cerium nitrate obtained in step (1), stirring at room temperature for 10 min to obtain a mixed aqueous solution of ammonium cerium nitrate and glucose;

[0087] (3) adding 1.0 mL of a 5.0 mg / mL manganese nitrate solution to the mixed aqueous solution of ammonium cerium nitrate and glucose obtained in step (2), and stirring at room temperature for 10 min to obtain a mixed aqueous solution of manganese nitrate, ammonium cerium nitrate and glucose;

[0088] (4) placing the mixed aqueous solution of manganese nitrate, ammonium cerium nitrate and glucose obtained in step (3) in a constant temperature drying oven and drying at 120° C. for 30 min to obtain a solid mixture of manganese nitrate, ammonium cerium nitrate and glucose;

[0089] (5) calcining the solid mixture of manganese nitrate, cerium ammonium nitrate and glucose obtained in step (4) at 500° C. for 2 h to obtain a manganese ion-doped cerium dioxide aerogel material with a product mass of 0.32 g;

[0090] (6) The manganese ion-doped cerium dioxide aerogel material prepared in step (5) is mixed with deionized water in a mass ratio of 3:1 and ground into a paste slurry. The slurry is then applied to the surface of an Al2O3 ceramic tube with two parallel, annular and separate gold electrodes on the outer surface. The tube is baked under an infrared lamp for 20 minutes to obtain a sensitive film based on manganese ion-doped cerium dioxide aerogel on the surface of the ceramic tube. The thickness of the sensitive film is 180 μm. A nickel-chromium alloy heating coil with a resistance value of 30 Ω is then passed through the Al2O3 ceramic tube as a heating wire. Finally, the tube is welded and packaged as a side-heated gas sensor. The length of the Al2O3 ceramic tube is 3 mm, the outer diameter is 1.1 mm, and the inner diameter is 0.7 mm. The width of the annular Au electrode is 0.7 mm, the distance between the two electrodes is 1.7 mm, and the thickness of the Au electrode is 0.08 mm.

[0091] (7) The acetone gas sensor based on the manganese ion-doped ceria aerogel material obtained in step (6) is aged at 280° C. for 12 hours to complete the aging treatment of the gas sensor, thereby obtaining a resistive acetone sensor based on the manganese ion-doped ceria aerogel material.

Claims

1. An acetone sensor based on metal ion-doped ceria aerogel, comprising an Al2O3 ceramic tube substrate, two parallel and separate annular Au electrodes coated on the outer surface of the Al2O3 ceramic tube substrate, a gas-sensitive film coated on the outer surface of the Al2O3 ceramic tube and the annular Au electrodes, and a nickel-chromium alloy heating coil passing through the interior of the Al2O3 ceramic tube; characterized by: The material of the gas sensitive film is metal ion doped ceria aerogel, and its preparation steps are as follows: (1) adding 0.5-1.0 g of ammonium cerium nitrate powder to 1.0-5.0 mL of water and stirring at room temperature for 5-10 minutes to obtain an aqueous solution of ammonium cerium nitrate; (2) adding 0.25-1.0 g of glucose to the aqueous solution of ammonium cerium nitrate obtained in step (1), stirring at room temperature for 5-10 min to obtain a mixed aqueous solution of ammonium cerium nitrate and glucose; (3) adding 1.0-3.0 mL of a 2.0-5.0 mg / mL aqueous solution of a metal nitrate to the mixed aqueous solution of ammonium cerium nitrate and glucose obtained in step (2), and stirring at room temperature for 5-10 minutes to obtain a mixed aqueous solution of the metal nitrate, ammonium cerium nitrate and glucose; (4) placing the mixed aqueous solution of metal nitrate, ammonium cerium nitrate and glucose obtained in step (3) in a constant temperature drying oven and drying it at 100-120° C. for 30-50 min to obtain a solid mixture of metal nitrate, ammonium cerium nitrate and glucose; (5) calcining the solid mixture of metal nitrate, ammonium cerium nitrate and glucose obtained in step (4) at 500-600° C. for 2-4 hours to obtain the metal ion-doped ceria aerogel.

2. The acetone sensor based on metal ion-doped ceria aerogel according to claim 1, characterized in that: The metal nitrate is one or more of manganese nitrate, copper nitrate or cobalt nitrate.

3. The acetone sensor based on metal ion-doped ceria aerogel according to claim 1, characterized in that: The thickness of the gas sensitive film is 180 to 220 μm.

4. The acetone sensor based on metal ion-doped ceria aerogel according to claim 1, characterized in that: The length of the Al2O3 ceramic tube is 3 to 5 mm, the outer diameter is 1.1 to 1.3 mm, and the inner diameter is 0.7 to 0.9 mm; the resistance of the nickel-chromium alloy heating coil is 30 to 40 Ω; the width of the annular Au electrode is 0.7 to 0.9 mm, the distance between the two Au electrodes is 1.7 to 1.9 mm, and the thickness of the Au electrode is 0.05 to 0.08 mm.

5. A method for preparing a resistive acetone sensor based on metal ion-doped ceria aerogel according to any one of claims 1 to 4, comprising the following steps: (1) mixing metal ion-doped ceria aerogel with deionized water in a mass ratio of 3 to 5:1 and grinding the mixture into a paste-like slurry; coating the paste onto the surface of an Al2O3 ceramic tube having two parallel and separate annular Au electrodes on its outer surface; (2) baking the device obtained in step (1) under an infrared lamp for 20 to 40 minutes. After the sensitive material is dried, a nickel-chromium alloy heating coil with a resistance value of 30 to 40 Ω is passed through the interior of the Al2O3 ceramic tube as a heating wire, and then welded and packaged as a indirectly heated gas sensor. (3) The device obtained in step (2) is aged at 280-320° C. for 8-12 hours to obtain the resistive acetone sensor based on metal ion-doped ceria aerogel.

6. Use of the resistive acetone sensor based on metal ion-doped ceria aerogel according to any one of claims 1 to 4 in acetone detection.

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