Lanthanum ferrite oxide modified by double noble metals Au and Pd and application of lanthanum ferrite oxide in acetone detection

Abstract

The invention discloses a lanthanum ferrite oxide modified by double noble metals Au and Pd and application of the lanthanum ferrite oxide to acetone detection, and relates to the technical field of acetone gas-sensitive materials. The preparation method comprises the following steps: preparing a LaFeO3 matrix by adopting a hydrothermal method, and carrying out surface modification on the LaFeO3 matrix by virtue of double noble metals of Au and Pd, so as to prepare the high-performance acetone gas sensitive material Xwt% Au-Ywt% Pd-LaFeO3. Wherein due to the synergistic catalysis of Au and Pd elements, the energy barrier of acetone oxidation reaction is remarkably reduced, and surface electron transfer and reaction activity are promoted, so that the working temperature is reduced, and the response value is increased. Specifically, when the lanthanum ferrite oxide modified by double noble metals Au and Pd prepared by the invention is used for detecting 1 ppm of acetone gas, the optimal working temperature is 170 DEG C, and the response value is 12.26.

Description

Technical Field

[0001] The present invention relates to the technical field of acetone gas-sensitive materials, and particularly to a lanthanum ferrite oxide modified with two noble metals Au and Pd and its application in detecting acetone. Background Art

[0002] Acetone, a colorless liquid at room temperature with a pungent odor, is a common volatile organic compound (VOC) widely present in chemical production, paint manufacturing, medical diagnosis (such as diabetes breath detection), and industrial waste gases. When the concentration of acetone is higher than 173 ppm, it can cause fatigue and nausea, and in severe cases, vomiting, coma, and even central nervous system symptoms. Long-term exposure can lead to pharyngitis, dermatitis, and damage to the liver and kidneys, seriously endangering human health. In addition, acetone is a marker gas in the breath of diabetic patients, and its concentration detection can be used for early disease diagnosis. Therefore, developing acetone detection technologies with high sensitivity and low operating temperature has important industrial and medical value.

[0003] Currently, acetone detection methods include gas chromatography-mass spectrometry, infrared spectroscopy, and gas sensors. Among them, although spectroscopic analysis instruments have high detection accuracy and good selectivity, they have the disadvantages of large volume, difficult maintenance, high cost, and inconvenient real-time on-line measurement. Gas sensors, on the other hand, have high detection sensitivity, simple preparation processes, low cost, small element size for easy portability, and are durable for large-scale popularization and use. The role of gas-sensitive materials in acetone detection is mainly manifested as follows: when the surface of the material comes into contact with acetone molecules, its electrical properties (such as resistance) change, thereby realizing real-time monitoring of the concentration. The perovskite-type composite oxide (such as LaFeO3) as a gas-sensitive material, being a p-type semiconductor, has become the focus of research on gas-sensitive materials due to its stable crystal structure, excellent redox performance, and modifiable characteristics. However, a single LaFeO3 material has problems such as high operating temperature (usually >250 °C), insufficient sensitivity, and poor selectivity in acetone detection, which limits its practical application.

[0004] To solve the above problems, the performance of perovskite materials is optimized by doping and surface modification. For example, noble metals are used for surface modification of perovskite materials. For example, CN109019696A discloses an Au-LaFeO3 nanocomposite material, and the Au-LaFeO3 nanocomposite material shows high sensitivity and fast response recovery to acetone. However, the synergistic effect of single noble metal modification is limited, and it is difficult to simultaneously meet the requirements of low operating temperature, high response value, and anti-interference ability.

[0005] Therefore, developing a perovskite material modified with two noble metals to achieve efficient detection of acetone gas has important scientific significance and application prospects. Summary of the Invention

[0006] In view of the above-mentioned prior art, the object of the present invention is to provide a lanthanum ferrite oxide modified with two noble metals Au and Pd. The present invention uses a hydrothermal method to prepare a LaFeO3 matrix, and the surface of the LaFeO3 matrix is modified with two noble metals Au and Pd to obtain a high-performance acetone gas-sensing material Xwt%Au-Ywt%Pd-LaFeO3. Among them, the synergistic catalytic effect of Au and Pd elements significantly reduces the energy barrier of the acetone oxidation reaction, promotes surface electron transfer and reaction activity, thereby reducing the working temperature and increasing the response value. Specifically, the lanthanum ferrite oxide modified with two noble metals Au and Pd prepared by the present invention has an optimal working temperature of 170 °C and a response value of 12.26 when detecting 1 ppm acetone gas.

[0007] To achieve the above object, the present invention adopts the following technical solutions:

[0008] In the first aspect of the present invention, there is provided a lanthanum ferrite oxide modified with two noble metals Au and Pd, which is prepared by the following method:

[0009] (1) Mix lanthanum nitrate and iron nitrate, dissolve them in deionized water, and then add citric acid to obtain a mixed solution; add a sodium hydroxide solution to the mixed solution to adjust the pH, stir and react, and after the reaction is completed, filter, wash and dry to obtain LaFeO3;

[0010] (2) Dissolve LaFeO3 in water to obtain a LaFeO3 solution; sequentially add chloroauric acid solution and palladium chloride solution to the LaFeO3 solution, and react to load Au and Pd on the surface of LaFeO3. After the reaction is completed, filter, wash, dry and calcine to obtain a lanthanum ferrite oxide modified with two noble metals Au and Pd.

[0011] Preferably, the addition ratio of lanthanum nitrate, iron nitrate, chloroauric acid, palladium chloride, citric acid and deionized water is (0.01 - 0.05) mol : (0.01 - 0.05) mol : (0.01 - 0.5) g : (0.01 - 0.5) g : (5 - 20) g : (50 - 150) mL.

[0012] Preferably, in step (1), the concentration of the sodium hydroxide solution is 1 - 2 mol / L, and the pH is adjusted to 10 - 12.

[0013] Preferably, in step (1), the stirring time is 0.5 - 1 h.

[0014] Preferably, in step (1), the reaction temperature is 160 - 200 °C and the reaction time is 12 - 24 h.

[0015] Preferably, in step (2), the calcination temperature is 400 - 600 °C and the calcination time is 2 - 4 h.

[0016] Preferably, the chemical formula of the double noble metal Au- and Pd-modified lanthanum ferrite oxide is Xwt% Au - Ywt% Pd - LaFeO3, where 0 < X ≤ 5 and 0 < Y ≤ 5.

[0017] In the second aspect of the present invention, there is provided the use of the above double noble metal Au- and Pd-modified lanthanum ferrite oxide in any one of the following 1) - 3):

[0018] 1) Detecting acetone;

[0019] 2) Non-invasive diagnosis of diabetes;

[0020] 3) Preparing an acetone gas sensor.

[0021] Preferably, the acetone gas concentration is 0.5 - 10 ppm.

[0022] Preferably, the acetone gas sensor is prepared by the following method:

[0023] Mix the double noble metal Au- and Pd-modified lanthanum ferrite oxide, deionized water, and terpineol in a ratio of (1 - 3) g : (5 - 10) mL : (1 - 3) mL to make a slurry; spin-coat the slurry on an alumina ceramic substrate to form a gas-sensitive film with a thickness of 50 - 200 μm, and age the gas-sensitive film at 180 - 200 °C for 12 - 24 h to obtain the acetone gas sensor.

[0024] Preferably, the operating temperature of the acetone gas sensor is 160 - 180 °C.

[0025] Advantages of the present invention:

[0026] 1. The present invention uses a hydrothermal method to prepare a LaFeO3 matrix, and performs surface modification on the LaFeO3 matrix with double noble metals Au and Pd to obtain a high-performance acetone gas-sensitive material Xwt% Au - Ywt% Pd - LaFeO3. Among them, the synergistic catalytic effect of Au and Pd elements significantly reduces the energy barrier of the acetone oxidation reaction, promotes surface electron transfer and reaction activity, thereby reducing the operating temperature and increasing the response value. Specifically, the double noble metal Au- and Pd-modified lanthanum ferrite oxide prepared in the present invention has an optimal operating temperature of 170 °C and a response value of 12.26 when detecting 1 ppm acetone gas.

[0027] 2. In the present invention, the dual noble metal modification of Au and Pd enhances the selective adsorption ability of the material for acetone molecules, inhibits the response to other interfering gases, and exhibits excellent selectivity. In the present invention, a combination of Au element and Pd element is used to modify the surface of the LaFeO3 matrix, which has a synergistic effect in improving the response value of the gas-sensitive material to acetone gas.

[0028] 3. The preparation process of the present invention is simple and controllable. The obtained material remains stable under humidity changes (relative humidity < 50%), and exhibits excellent stability during long-term use (the response value changes < 5% within one month), making it suitable for acetone detection in industrial and medical fields. At the same time, the acetone gas sensor prepared by the present invention has a low working temperature, low energy consumption, and is easy to be integrated into portable devices, showing broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 : XRD pattern of the lanthanum ferrite oxide modified with dual noble metals Au and Pd prepared in Example 1;

[0030] Figure 2 : SEM image of the lanthanum ferrite oxide modified with dual noble metals Au and Pd prepared in Example 1;

[0031] Figure 3 : EDS Mapping images of Au, Pd, and La elements in the lanthanum ferrite oxide modified with dual noble metals Au and Pd prepared in Example 1;

[0032] Figure 4 : Relationship diagram between the gas-sensitive performance and temperature of the materials prepared in Example 1 and Comparative Examples 1-3 for 1 ppm acetone gas;

[0033] Figure 5 : Relationship diagram between the gas-sensitive performance and humidity of the lanthanum ferrite oxide modified with dual noble metals Au and Pd prepared in Example 1 for 1 ppm acetone gas;

[0034] Figure 6 : Schematic diagram of the long-term gas-sensitive stability of the lanthanum ferrite oxide modified with dual noble metals Au and Pd prepared in Example 1 for 1 ppm acetone gas. DETAILED DESCRIPTION OF THE INVENTION

[0035] It should be noted that the following detailed description is illustrative and is intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present application belongs.

[0036] In order to enable those skilled in the art to more clearly understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below in combination with specific examples.

[0037] The experimental materials used in the embodiments of the present invention are all conventional experimental materials in the art and can be obtained through commercial channels.

[0038] Example 1: Preparation of lanthanum ferrite oxide modified with dual noble metals Au and Pd

[0039] (1) After mixing lanthanum nitrate and iron nitrate, dissolve them in deionized water, and then add citric acid to obtain a mixed solution; slowly add 1 mol / L sodium hydroxide solution to the mixed solution, adjust the pH of the solution to 11, continue stirring for 0.5 h, place the stirred solution at 180 °C for reaction for 18 h, after the reaction ends, filter the reaction product, collect the filtered precipitate, wash the precipitate 3 times with deionized water and ethanol, and then vacuum dry at 80 °C for 8 h to obtain LaFeO3;

[0040] (2) Disperse LaFeO3 in 50 mL of water to obtain a LaFeO3 solution, sequentially add chloroauric acid solution and palladium chloride solution to the LaFeO3 solution, place it at 70 °C for reaction for 3 h, so that the mass percentages of Au element and Pd element are both 2 wt%, after the reaction ends, filter, wash and dry, and then calcine at 500 °C for 2 h to obtain the dual-noble-metal-modified lanthanum ferrite oxide 2 wt% Au-2 wt% Pd-LaFeO3;

[0041] During the preparation process, the addition amount ratio of lanthanum nitrate, iron nitrate, chloroauric acid, palladium chloride, citric acid and deionized water is 4.330 g:4.040 g:0.082 g:0.081 g:10 g:100 mL.

[0042] Example 2: Preparation of lanthanum ferrite oxide modified with dual noble metals Au and Pd

[0043] (1) After mixing lanthanum nitrate and iron nitrate, dissolve them in deionized water, and then add citric acid to obtain a mixed solution; slowly add 1.5 mol / L sodium hydroxide solution to the mixed solution, adjust the pH of the solution to 10, continue stirring for 1 h, place the stirred solution at 200 °C for reaction for 12 h, after the reaction ends, filter the reaction product, collect the filtered precipitate, wash the precipitate 4 times with deionized water and ethanol, and then vacuum dry at 80 °C for 10 h to obtain LaFeO3;

[0044] (2) Disperse LaFeO3 in 60 mL of water to obtain a LaFeO3 solution. Sequentially add chloroauric acid solution and palladium chloride solution to the LaFeO3 solution, and react at 80 °C for 2 h so that the mass percentages of Au element and Pd element are 1 wt% and 3 wt% respectively. After the reaction is completed, filter, wash and dry, and then calcine at 600 °C for 2 h to obtain lanthanum ferrite oxide modified with double noble metals 1 wt% Au - 3 wt% Pd - LaFeO3;

[0045] During the preparation process, the addition amount ratio of lanthanum nitrate, iron nitrate, chloroauric acid, palladium chloride, citric acid and deionized water is 4.330 g:4.040 g:0.041 g:0.121 g:15 g:120 mL.

[0046] Example 3: Preparation of lanthanum ferrite oxide modified with double noble metals Au and Pd

[0047] (1) Mix lanthanum nitrate and iron nitrate, dissolve them in deionized water, and then add citric acid to obtain a mixed solution. Slowly drop 2 mol / L sodium hydroxide solution into the mixed solution to adjust the pH of the solution to 12, continue stirring for 1 h, place the stirred solution at 160 °C for reaction for 24 h. After the reaction is completed, filter the reaction product, collect the filtered precipitate, wash the precipitate 5 times with deionized water and ethanol, and then vacuum dry at 80 °C for 6 h to obtain LaFeO3;

[0048] (2) Disperse LaFeO3 in 40 mL of water to obtain a LaFeO3 solution. Sequentially add chloroauric acid solution and palladium chloride solution to the LaFeO3 solution, and react at 80 °C for 2 h so that the mass percentages of Au element and Pd element are 3 wt% and 1 wt% respectively. After the reaction is completed, filter, wash and dry, and then calcine at 400 °C for 4 h to obtain lanthanum ferrite oxide modified with double noble metals 3 wt% Au - 1 wt% Pd - LaFeO3;

[0049] During the preparation process, the addition amount ratio of lanthanum nitrate, iron nitrate, chloroauric acid, palladium chloride, citric acid and deionized water is 4.330 g:4.040 g:0.123 g:0.041 g:8 g:80 mL.

[0050] Example 4: Preparation of acetone gas-sensitive material

[0051] Mix the lanthanum ferrite oxide modified with double noble metals 2 wt% Au - 2 wt% Pd - LaFeO3 prepared in Example 1, deionized water and terpineol in a ratio of 1 g:5 mL:1 mL to obtain a slurry. Spin-coat the slurry on the surface of an alumina ceramic substrate at a speed of 800 rpm to form a gas-sensitive film with a thickness of 100 μm. Place the gas-sensitive film in the air and age it at 180 °C for 18 h to obtain an acetone gas-sensitive sensor.

[0052] Comparative Example 1:

[0053] The difference between this comparative example and Example 1 is that chloroauric acid and palladium chloride were not added. The specific steps are as follows:

[0054] (1) After mixing lanthanum nitrate and iron nitrate, dissolve them in deionized water, then add citric acid to obtain a mixed solution; slowly add 1 mol / L sodium hydroxide solution to the mixed solution to adjust the pH of the solution to 11, continue stirring for 0.5 h, place the stirred solution at 180 °C for reaction for 18 h, after the reaction is completed, filter the reaction product, collect the filtered precipitate, wash the precipitate 3 times with deionized water and ethanol, and then vacuum dry at 80 °C for 8 h to obtain LaFeO3;

[0055] (2) Disperse LaFeO3 in 50 mL of water to obtain a LaFeO3 solution, heat it at 70 °C for 3 h, filter, wash and dry it, and then calcine it at 500 °C for 2 h to obtain lanthanum ferrite oxide modified with double precious metals, LaFeO3;

[0056] During the preparation process, the addition ratio of lanthanum nitrate, iron nitrate, citric acid and deionized water is 4.330 g: 4.040 g: 10 g: 100 mL.

[0057] Comparative Example 2:

[0058] The difference between this comparative example and Example 1 is that palladium chloride was not added. The specific steps are as follows:

[0059] (1) After mixing lanthanum nitrate and iron nitrate, dissolve them in deionized water, then add citric acid to obtain a mixed solution; slowly add 1 mol / L sodium hydroxide solution to the mixed solution to adjust the pH of the solution to 11, continue stirring for 0.5 h, place the stirred solution at 180 °C for reaction for 18 h, after the reaction is completed, filter the reaction product, collect the filtered precipitate, wash the precipitate 3 times with deionized water and ethanol, and then vacuum dry at 80 °C for 8 h to obtain LaFeO3;

[0060] (2) Disperse LaFeO3 in 50 mL of water to obtain a LaFeO3 solution, add palladium chloride solution to the LaFeO3 solution, react at 70 °C for 3 h to make the mass percentage of Pd element be 2 wt%, after the reaction is completed, filter, wash and dry it, and then calcine it at 500 °C for 2 h to obtain lanthanum ferrite oxide modified with double precious metals 2 wt% Au-LaFeO3;

[0061] During the preparation process, the addition ratio of lanthanum nitrate, iron nitrate, chloroauric acid, citric acid and deionized water is 4.330 g: 4.040 g: 0.081 g: 10 g: 100 mL.

[0062] Comparative Example 3:

[0063] The difference between this comparative example and Example 1 is that chloroauric acid was not added. The specific steps are as follows:

[0064] (1) After mixing lanthanum nitrate and iron nitrate, dissolve them in deionized water, then add citric acid to obtain a mixed solution; slowly drip 1 mol / L sodium hydroxide solution into the mixed solution to adjust the pH of the solution to 11, continue stirring for 0.5 h, place the stirred solution at 180 °C for reaction for 18 h, after the reaction is completed, filter the reaction product, collect the filtered precipitate, wash the precipitate 3 times with deionized water and ethanol, and then vacuum dry at 80 °C for 8 h to obtain LaFeO3;

[0065] (2) Disperse LaFeO3 in 50 mL of water to obtain a LaFeO3 solution, add palladium chloride solution to the LaFeO3 solution, and react at 70 °C for 3 h so that the mass percentage of Pd element is 2 wt%, after the reaction is completed, filter, wash and dry, and then calcine at 500 °C for 2 h to obtain the double-precious-metal-modified lanthanum ferrite oxide 2 wt% Pd-LaFeO3;

[0066] During the preparation process, the addition ratio of lanthanum nitrate, iron nitrate, palladium chloride, citric acid and deionized water is 4.330 g:4.040 g:0.081 g:10 g:100 mL.

[0067] Test Example 1: Structural Characterization

[0068] Perform structural characterization on the double-precious-metal 2 wt% Au-2 wt% Pd-LaFeO3 prepared in Example 1, and the results are as Figures 1-3 shown.

[0069] Figure 1 is the XRD pattern of the double-precious-metal Au and Pd-modified lanthanum ferrite oxide prepared in Example 1. It can be seen from Figure 1 that the crystallization peaks correspond to the crystal phases of (101), (121) and (220) of LaFeO3 (No. 37-1493), Figure 2 is the SEM image of the double-precious-metal Au and Pd-modified lanthanum ferrite oxide prepared in Example 1 at a magnification of 200 nm. It can be seen from Figure 2 that the double-precious-metal Au and Pd-modified lanthanum ferrite oxide presents a typical nanoparticle structure, with a large specific surface area and porosity, and many reaction sites and transport channels for gas molecules. It can be seen from Figure 3 the EDS-Mapping schematic diagram of Au, Pd and La elements that the elements Au, Pd and La exist in the material. Thus, it can be seen that Au and Pd are successfully doped into LaFeO3.

[0070] Experimental Example 2:

[0071] The lanthanum ferrite oxide modified with double noble metals Au and Pd prepared in Example 1 and the materials prepared in Comparative Examples 1-3 were coated on the induction film, and their gas-sensing responses (Rg / Ra) to acetone gas were detected. The results are as Figures 4-6 shown. Among them, Ra is the resistance of the sensor in air, and Rg is the resistance of the gas to be measured. The experimental environment is: RH is 20%, and the ambient temperature is 20 °C.

[0072] It can be seen from Figure 4 that the optimal working temperature of the lanthanum ferrite oxide modified with double noble metals Au and Pd prepared in the present invention is 170 °C. At the working temperature of 170 °C, the response value of the lanthanum ferrite oxide 2wt% Au-2wt% Pd-LaFeO3 modified with double noble metals prepared in the present invention to 1 ppm of acetone gas is 12.26, the response value of LaFeO3 prepared in Comparative Example 1 to 1 ppm of acetone gas is 2.37, the response value of 2wt% Au-LaFeO3 prepared in Comparative Example 2 to 1 ppm of acetone gas is 8.59, and the response of 2wt% Pd-LaFeO3 prepared in Comparative Example 3 to 1 ppm of acetone gas is 7.93. Thus, it can be seen that by loading and modifying the surface of the LaFeO3 material with noble metals Au and Pd, there is a synergistic effect in improving the response value of the material to acetone gas.

[0073] Figure 5 shows the long-term stability of the lanthanum ferrite oxide 2wt% Au-2wt% Pd-LaFeO3 modified with double noble metals prepared in the present invention to 1 ppm of acetone gas. It can be seen from the figure that within one month, the change rate of the response value of the lanthanum ferrite oxide 2wt% Au-2wt% Pd-LaFeO3 modified with double noble metals prepared in the present invention to 1 ppm of acetone gas is within 6%, indicating that the material has extremely high long-term gas-sensing stability.

[0074] Figure 6 shows the relationship diagram between the gas-sensing performance of the lanthanum ferrite oxide 2wt% Au-2wt% Pd-LaFeO3 modified with double noble metals prepared in the present invention and humidity to 1 ppm of acetone gas. It can be seen from the figure that as the relative humidity increases, the gas-sensing performance gradually decreases. When the relative humidity exceeds 40%, the gas-sensing performance drops sharply, but within 40%, the change rate of the acetone gas-sensing performance of the lanthanum ferrite oxide modified with double noble metals Au and Pd is within 8%, indicating extremely high gas-sensing relative humidity resistance.

[0075] The above are only the preferred embodiments of the present application and are not intended to limit the present application. For those skilled in the art, various modifications and variations can be made to the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included within the protection scope of the present application.

Claims

1. A double-precious-metal Au and Pd modified lanthanum ferrite oxide, characterized in that, It is prepared by the following method: (1) After mixing lanthanum nitrate and iron nitrate, dissolve them in deionized water, and then add citric acid to obtain a mixed solution; add sodium hydroxide solution to the mixed solution to adjust the pH, stir and react. After the reaction is completed, filter, wash and dry to obtain LaFeO3; (2) After dissolving LaFeO3 in water, obtain a LaFeO3 solution; sequentially add chloroauric acid solution and palladium chloride solution to the LaFeO3 solution, and react to load Au and Pd on the surface of LaFeO3. After the reaction is completed, filter, wash, dry and calcine to obtain lanthanum ferrite oxide modified with double noble metals Au and Pd.

2. The lanthanum ferrite oxide modified with double noble metals Au and Pd according to claim 1, wherein The addition amount ratio of lanthanum nitrate, iron nitrate, chloroauric acid, palladium chloride, citric acid and deionized water is (0.01 - 0.05) mol:(0.01 - 0.05) mol:(0.01 - 0.5) g:(0.01 - 0.5) g:(5 - 20) g:(50 - 150) mL.

3. The lanthanum ferrite oxide modified with double noble metals Au and Pd as described in claim 1, characterized in that, In step (1), the concentration of the sodium hydroxide solution is 1 - 2 mol / L, and the pH is adjusted to 10 - 12; the stirring time is 0.5 - 1 h.

4. The lanthanum ferrite oxide modified with double noble metals Au and Pd as described in claim 1, characterized in that, In step (1), the reaction temperature is 160 - 200 °C and the reaction time is 12 - 24 h.

5. The lanthanum ferrite oxide modified with double noble metals Au and Pd as described in claim 1, wherein The calcination temperature is 400 - 600 °C and the calcination time is 2 - 4 h.

6. Application of the lanthanum ferrite oxide modified with double noble metals Au and Pd according to any one of claims 1 - 5 in any one of the following 1) - 3): 1) Detecting acetone; 2) Non-invasive diagnosis of diabetes; 3) Preparing an acetone gas sensor.

7. The application according to claim 6, characterized in that, The concentration of acetone gas is 0.5 - 10 ppm.

8. The application according to claim 6, characterized in that, The acetone gas sensor is prepared by the following method: Mix the lanthanum ferrite oxide modified with double noble metals Au and Pd according to any one of claims 1 - 5, deionized water and terpineol in a ratio of (1 - 3) g:(5 - 10) mL:(1 - 3) mL to form a slurry; spin-coat the slurry on an alumina ceramic substrate to form a gas-sensitive film with a thickness of 50 - 200 μm, and age the gas-sensitive film at 180 - 200 °C for 12 - 24 h to obtain the acetone gas sensor.

9. The application according to claim 6, characterized in that, The working temperature of the acetone gas sensor is 160 - 180 °C.

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