An acetone gas sensitive material, a preparation method thereof and application thereof in an acetone gas sensor

Abstract

The application relates to an acetone gas-sensitive material, a preparation method thereof and application thereof in an acetone gas sensor. The acetone gas-sensitive material is composed of a YbFeO3-BiFeO3 composite material, and a p-p heterojunction is formed between YbFeO3 and BiFeO3.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of based on YbFeO3-BiFeO3 Composite sensitive material and its preparation method and application in acetone gas sensor, belong to semiconductor metal oxide gas sensor technical field. BACKGROUND

[0002] With the development of medicine, respiratory biomarker detection becomes a promising non-invasive disease diagnosis technology. As the respiratory biomarker of diabetes, acetone detection provides a simple, effective and non-invasive method for early diagnosis of diabetes. The acetone concentration in the exhaled breath of healthy people is less than 0.9 ppm, while the acetone concentration in diabetic patients is higher than 1.8 ppm. Therefore, it is essential to develop a high-sensitivity, low-detection-limit acetone gas sensor for the prevention and diagnosis of diabetes.

[0003] Currently, researchers have developed acetone gas sensors based on binary metal oxides SnO2, WO3, ZnO, Fe2O3, Co3O4, CuO, NiO, etc. However, they still face the challenges of low sensitivity, high detection limit, and especially high operating temperature, which hinders their application in diabetes diagnosis. Although perovskite ternary oxides ABO3 (such as BiFeO3) exhibit unique advantages in gas-sensitive materials due to their highly adjustable structure and chemical composition, non-stoichiometric stability after doping, etc. However, the existing perovskite ternary oxides (such as BiFeO3) have low acetone gas sensing performance and still face challenges in detecting low-concentration acetone gas. SUMMARY

[0004] Therefore, the present application provides an acetone gas-sensitive material, its preparation method and the application of YbFeO3-BiFeO3 composite sensitive material-based acetone gas sensor.

[0005] In one aspect, the present application provides an acetone gas-sensitive material, characterized in that the composition of the acetone gas-sensitive material is YbFeO3-BiFeO3 composite material, and a p-p heterojunction is formed between YbFeO3 and BiFeO3.

[0006] In the present application, two gas-sensitive materials are combined to form a heterojunction structure, and the synergistic effect of the two can further improve the gas-sensitive performance, thereby obtaining a high-performance acetone gas sensor.

[0007] The specific working principle is as follows: when YbFeO3-BiFeO3 sensor is exposed to air, oxygen molecules are adsorbed on the surface, and are converted into adsorbed oxygen ions (O2 - 、O - 、O 2-). Therefore, the hole concentration of the surface increases, resulting in a decrease in resistance. When the sensor is exposed to acetone gas, the acetone molecules undergo a redox reaction with oxygen ions, and electrons are released back into the composite material. At this time, the electrons recombine with the holes, resulting in a decrease in hole concentration, which leads to an increase in resistance. By measuring the change in resistance of the sensor before and after it is in contact with acetone gas, the purpose of detecting acetone is achieved. The response of the acetone sensor is defined as the ratio of the resistance R g of the sensor in acetone to the resistance R a in air.

[0008] Compared with BiFeO3, the YbFeO3-BiFeO3 composite material improves the response intensity to acetone gas due to the formation of p-p heterojunction and the increase of Fe 2+ / Fe 3+ redox pairs. On the one hand, since the band gap of YbFeO3 (1.7 eV) is smaller than that of BiFeO3, electrons will transfer from BiFeO3 to YbFeO3, and holes will transfer from YbFeO3 to BiFeO3. The energy band at the heterojunction bends until the Fermi level reaches equilibrium. The formation of the heterojunction can promote interface electron transfer and interface reaction, and enhance the adsorption of surface oxygen, thereby improving the gas sensing performance. On the other hand, the YbFeO3-BiFeO3 composite material prepared based on this method has more Fe 2+ / Fe 3+ redox pairs. During the oxygen adsorption process, Fe 2+ is oxidized to Fe 3+ , releasing electrons to provide adsorbed oxygen, which promotes the adsorption of a large number of oxygen ions. After the reaction with acetone, the electrons are released into the composite material, promoting the reduction of Fe 3+ to Fe 2+ . Therefore, the increase in Fe 2+ / Fe 3+ concentration also promotes the response of YbFeO3-BiFeO3 composite material to acetone.

[0009] Preferably, the content of YbFeO3 in the YbFeO3-BiFeO3 composite material is 1-25 wt.%, preferably 5-20 wt.%, more preferably 6-16 wt.%, and most preferably 10-14 wt.%.

[0010] Preferably, the particle size of the YbFeO3-BiFeO3 composite material is 0.2-5 μm, preferably 0.2-1 μm.

[0011] In a second aspect, the present application provides a preparation method of an acetone gas sensitive material, comprising:

[0012] 1) taking Yb2O3 powder and BiFeO3 powder, mixing, baking at 650-750℃ for 3-5h, to obtain baked powder;

[0013] 2) stirring the obtained baked powder in nitric acid solution, then washing and drying, to obtain the YbFeO3-BiFeO3 composite material.

[0014] Preferably, the mass of the Yb2O3 powder is 1-15wt.% of the mass of the BiFeO3 powder;

[0015] The concentration of the nitric acid solution is 1-3mol / L;

[0016] The stirring speed is 600-800rpm, and the stirring time is 0.5-2h.

[0017] In a third aspect, the present application provides a YbFeO3-BiFeO3 composite material-based acetone gas sensor, characterized in that it comprises a YbFeO3-BiFeO3 sensitive film prepared from the above acetone gas sensitive material.

[0018] Preferably, the YbFeO3-BiFeO3 composite material-based acetone gas sensor comprises a substrate, an interdigital electrode formed on one side surface of the substrate, a YbFeO3-BiFeO3 sensitive film, and a heating electrode formed on the other side surface of the substrate.

[0019] Preferably, the thickness of the YbFeO3-BiFeO3 sensitive film is 40-80μm.

[0020] Preferably, the interdigital electrode is composed of Au, Cr or Ag-Pd. Preferably, the heating electrode is composed of Pt, Cu or Ni-Cr. Preferably, the substrate is composed of Al2O3 or Si.

[0021] Preferably, in the detection of acetone gas, the optimal working temperature of the YbFeO3-BiFeO3 composite material-based acetone gas sensor is ≤200℃, and the response to 10ppm acetone at the optimal working temperature is as high as 32.6.

[0022] In still another aspect, the present application provides a preparation method of a YbFeO3-BiFeO3 composite material-based acetone gas sensor, wherein the preparation method of the YbFeO3-BiFeO3 sensitive film comprises:

[0023] (1) dispersing YbFeO3-BiFeO3 composite material in an organic solvent to obtain slurry;

[0024] (2) The obtained slurry is coated on the surface of the interdigital electrode, and then dried and aged to obtain a YbFeO3-BiFeO3 sensitive film.

[0025] Preferably, the ratio of the YbFeO3-BiFeO3 composite material to the organic solvent is (10-20) mg:(15-30) μL; preferably, the organic solvent is at least one of terpineol, ethanol, acetone and glycerol.

[0026] Preferably, the coating method is a screen printing method.

[0027] The drying temperature is 200-300℃, and the time is 4-12h.

[0028] The aging treatment temperature is 200-300℃, and the time is 24-48h.

[0029] Beneficial effects:

[0030] 1. The YbFeO3-BiFeO3 composite material is successfully prepared by simple solid phase sintering and acid etching, and the preparation method is simple and low in cost.

[0031] 2. The YbFeO3-BiFeO3 composite material significantly reduces the detection lower limit of the BiFeO3-based sensor (the theoretical calculation is 25ppb), improves the sensitivity (S=7@400ppb; S=32.6@10ppm Figure 5 ), and greatly reduces the working temperature (≤200℃); in addition, the sensor has good stability and selectivity. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 It is a structure schematic diagram of the acetone gas sensor of the application; in the figure, 1-YbFeO3-BiFeO3 sensitive film; 2-interdigital electrode; 3-substrate; 4-heating electrode.

[0033] Figure 2 It is an X-ray diffraction spectrum of the YbFeO3-BiFeO3 composite material prepared in Example 1.

[0034] Figure 3 It is a response value comparison diagram of the BiFeO3 in Comparative Example 1 and the YbFeO3-BiFeO3 sensor prepared in Example 1 to 10ppm acetone gas at 160-300℃.

[0035] Figure 4 It is a response and recovery curve comparison diagram of the BiFeO3 in Comparative Example 1 and the YbFeO3-BiFeO3 sensor prepared in Example 1 to different concentrations of acetone at the optimal working temperature, and a response value comparison diagram.

[0036] Figure 5 Response and recovery curves of YbFeO3-BiFeO3 sensor prepared in Example 1 to different concentrations of acetone at different temperatures and response values;

[0037] Figure 6 Response of YbFeO3-BiFeO3 sensor prepared in Example 1 to different reducing gases;

[0038] Figure 7 Response and recovery curves of YbFeO3-BiFeO3 sensor prepared in Example 5 to 10 ppm acetone at 220°C working temperature; from the figure, it can be seen that the response of YbFeO3-BiFeO3 sensor to 10 ppm acetone can reach 30.3.

[0039] Figure 8 Response and recovery curves of YbFeO3-BiFeO3 sensor prepared in Example 5 to 10 ppm acetone at 220°C working temperature; from the figure, it can be seen that the response of YbFeO3-BiFeO3 sensor to 10 ppm acetone can reach 30.3. DETAILED DESCRIPTION

[0040] The present application is further illustrated by the following examples, which should not be construed as limiting the present application.

[0041] In the present disclosure, the acetone gas sensor based on YbFeO3-BiFeO3 composite material comprises a gas-sensitive film based on YbFeO3-BiFeO3 composite material, an interdigital electrode, a substrate, and a heating electrode. Figure 1 As shown in the figure, the acetone gas sensor based on YbFeO3-BiFeO3 composite material comprises a gas-sensitive film based on YbFeO3-BiFeO3 composite material, an interdigital electrode, a substrate, and a heating electrode.

[0042] In the present application, a small amount of Yb2O3 and BiFeO3 powder is uniformly mixed, then high-temperature calcination and acid corrosion are performed to obtain pure-phase YbFeO3-BiFeO3 composite material. An appropriate amount of the above composite material is mixed with terpineol, uniformly ground to obtain a slurry with moderate viscosity, which is screen printed on a substrate with an interdigital electrode and a heating electrode, and heated and aged to obtain an acetone gas sensor based on YbFeO3-BiFeO3 composite material. The preparation method of the acetone gas sensor based on YbFeO3-BiFeO3 composite material is described exemplarily below.

[0043] Preparation of BiFeO3 powder material. In the present application, BiFeO3 powder is prepared by hydrothermal method, sol-gel method, solid-phase reaction method, electrospinning method, etc., as long as BiFeO3 is rhombohedral crystal phase and the average size is less than 3 μm (preferably 0.1-2 μm, more preferably 0.1-1 μm).

[0044] As an example of preparing BiFeO3 powder by hydrothermal method, nine water ferric nitrate and five water bismuth nitrate are added to dilute nitric acid solution, continuously stirred until completely dissolved to obtain a mixed solution. A certain concentration of potassium hydroxide solution is added to adjust the pH and carry out the reaction, and the obtained reaction product is centrifuged, washed; the reaction product is added to an aqueous solution containing potassium hydroxide and potassium nitrate, stirred uniformly, and transferred to a hydrothermal kettle for heating reaction, and after centrifugation, washing and drying, the initial bismuth ferrite powder is obtained.

[0045] In an optional embodiment, the concentrations of nine water ferric nitrate and five water bismuth nitrate in the mixed solution can be 12-18 mmol respectively. The volume of the dilute nitric acid solution is 100 mL, and the concentration is 1-3 mol / L. The concentration of the potassium hydroxide solution can be 10-12 mol / L, so that the pH of the mixed solution is 8-14. The concentration of potassium hydroxide in the aqueous solution containing potassium hydroxide and potassium nitrate is 10-12 mol / L, and the concentration of potassium nitrate is 2.2-2.8 mol / L. The hydrothermal time can be 20-48 h, and the hydrothermal temperature can be 180-220 ℃.

[0046] A small amount of Yb2O3 and BiFeO3 powder is uniformly mixed, and then high-temperature calcination and acid corrosion are carried out to obtain pure-phase YbFeO3-BiFeO3 composite material. The raw material content of Yb2O3 is 1wt.%-15wt.%, preferably 5wt.-10wt.%, more preferably 10wt.%; the calcination temperature is 650-750 ℃, and the sintering time is 3-5 h, and the purpose of calcination is to form YbFeO3-BiFeO3 composite material. The concentration of nitric acid is 1-3 mol / L, and the stirring time is 0.5-2 h, and the purpose of acid corrosion is to remove Bi 12 (Bi 0.5 Fe 0.5 )O 19.5 impurities and at the same time expose Fe active sites, increase surface adsorbed oxygen, and thus enhance gas sensing performance.

[0047] An appropriate amount of YbFeO3-BiFeO3 composite material is mixed with terpineol, uniformly ground to obtain a slurry with moderate viscosity, screen printed on a substrate with interdigital electrodes and heating electrodes, heated to remove terpineol, and aged to obtain an acetone gas sensor based on YbFeO3-BiFeO3 composite material. The heating temperature is 200-300 ℃, and the time is 4-12 h; the aging temperature is 200-300 ℃, and the time is 24-48 h.

[0048] The YbFeO3-BiFeO3 acetone gas sensor is placed in a dynamic gas sensing test system, and the resistance change is measured to detect acetone gas of different concentrations.

[0049] The following further illustrates the embodiments in detail. It should also be understood that the following embodiments are only used to further illustrate the present application and cannot be understood as limiting the scope of protection of the present application. Some non-essential improvements and adjustments made by those skilled in the art according to the above content of the present application all belong to the protection scope of the present application. The specific process parameters and the like described below are only one example in the appropriate range, i.e. those skilled in the art can make appropriate selection within the range through the description herein, and are not limited to the specific values of the following examples.

[0050] Example 1

[0051] The acetone gas sensor based on YbFeO3-BiFeO3 composite material and the preparation method thereof are as follows:

[0052] (1) Take iron nitrate nonahydrate and bismuth nitrate pentahydrate with a molar ratio of 1:1, and add them to a dilute nitric acid solution with a concentration of 2 mol / L, and continuously stir until completely dissolved;

[0053] (2) Add 12 mol / L potassium hydroxide for reaction, and adjust the pH of the solution to 14, and centrifuge and wash the obtained reaction product;

[0054] (3) Add the reaction product prepared in step (2) to an aqueous solution of 12 mol / L potassium hydroxide and 2 mol / L potassium nitrate, stir uniformly, and then transfer to a hydrothermal kettle for reaction, with a hydrothermal time of 24 h and a hydrothermal temperature of 180℃. After centrifugation, washing and drying, BiFeO3 powder is obtained;

[0055] (4) Uniformly mix 10wt.% Yb2O3 and BiFeO3 powder, and then calcine at 700℃ for 4 h; place the obtained composite material in a 2 mol / L HNO3 solution, and stir uniformly with a magnetic stirrer; wash the above-mentioned powder with deionized water and anhydrous ethanol several times, and then dry at 70℃ for 24 h to obtain a pure-phase YbFeO3-BiFeO3 composite material; the content of YbFeO3 in the YbFeO3-BiFeO3 composite material is 13.4wt.%;

[0056] (5) Mix 10 mg of YbFeO3-BiFeO3 powder with 20 μL of terpineol, uniformly grind to obtain a slurry with appropriate viscosity, and then coat it on one side of an Al2O3 ceramic sheet with Au interdigital electrodes using a screen printing technology, with a film thickness of 60 μm;

[0057] (6) Place the sensitive film prepared in step (5) in an oven, and dry at 250℃ for 6 h, and then weld the pins of the sensor on a device base;

[0058] (7) The sensor prepared in step (6) is placed in a dynamic gas sensitive test system for aging treatment, the temperature is 250°C, and the time is 24 h, to obtain a YbFeO3-BiFeO3 acetone gas sensor.

[0059] Figure 2 The X-ray diffraction spectrum of the YbFeO3-BiFeO3 composite material prepared in Example 1 shows that only YbFeO3 and BiFeO3 exist in the YbFeO3-BiFeO3 composite material, and there is no other impurity phase.

[0060] Figure 3 The response of the YbFeO3-BiFeO3 sensor in Example 1 to 10 ppm acetone gas at 160-300°C is compared with that of the BiFeO3 sensor, and the response value is increased by 16.6 times, and the optimal working temperature is reduced from 280°C to 200°C, which shows that the introduction of YbFeO3 and the formation of a p-p heterojunction with BiFeO3 greatly improve the gas sensitive response to acetone and reduce the working temperature.

[0061] Figure 4 The response and recovery curves of the YbFeO3-BiFeO3 sensor in Example 1 to different concentrations of acetone at the optimal working temperature and the change of the response with the concentration of acetone show that the response value of the YbFeO3-BiFeO3 sensor increases rapidly with the increase of the concentration of acetone, and the response and the concentration of acetone show a good linear growth relationship in the concentration range of 0.4-1 ppm and 2-10 ppm of acetone, respectively.

[0062] Figure 5 The response and recovery curves of the YbFeO3-BiFeO3 sensor prepared in Example 1 to different concentrations of acetone at different temperatures and the change of the response with the concentration of acetone show that the optimal working temperature of the YbFeO3-BiFeO3 sensor to low concentration acetone can be as low as 160°C, and the response to 400 ppb acetone can reach 7 at this time. The lower limit of detection of the sensor is low, and the theoretical calculation value reaches 25 ppb.

[0063] Figure 6 The response of the YbFeO3-BiFeO3 sensor prepared in Example 1 to different reducing gases shows that the sensor has good selectivity to acetone gas.

[0064] Figure 7In order to compare the response and recovery curves of the YbFeO3-BiFeO3 sensors prepared with different Yb2O3 contents to 10 ppm acetone at 220℃ and the change of the response with the Yb2O3 content, it can be seen from the figure that the response of the sensor increases approximately linearly with the increase of the Yb2O3 content, and the highest value of 31.1 is obtained when the Yb2O3 content is 10wt.%; when the Yb2O3 content is further increased to 15wt.%, the response is reduced due to the presence of impurities.

[0065] Example 2

[0066] The YbFeO3-BiFeO3 composite material-based acetone gas sensor and the preparation method thereof are as follows:

[0067] (1) Take iron nitrate nonahydrate and bismuth nitrate pentahydrate with a molar ratio of 1:1, and add them to a dilute nitric acid solution with a concentration of 2 mol / L, continuously stir until completely dissolved, and then add 0.75g of tartaric acid;

[0068] (2) Heat the solution prepared in step (1) at 250℃ until all the water is evaporated, and then calcine at 600℃ for 2h to obtain BiFeO3 powder;

[0069] (3) Mix 1wt.% Yb2O3 and BiFeO3 powder uniformly, and then calcine at 700℃ for 4h; place the obtained composite material in a 2mol / L HNO3 solution, and stir uniformly with a magnetic stirrer; wash the above-mentioned powder with deionized water and anhydrous ethanol several times, and then dry at 70℃ for 24h to obtain YbFeO3-BiFeO3 composite material; the content of YbFeO3 in the YbFeO3-BiFeO3 composite material is 1.3wt.%;

[0070] (5) Mix 10mg of YbFeO3-BiFeO3 powder with 20μL of terpineol, uniformly grind to obtain a slurry with appropriate viscosity, and then coat it on the side of the Al2O3 ceramic sheet with Au interdigital electrodes using screen printing technology, and the thickness of the film is 60μm;

[0071] (6) Place the sensitive film prepared in step (5) in an oven and dry at 250℃ for 6h, and then weld the pins of the sensor on the device base;

[0072] (7) Place the sensor prepared in step (6) in a dynamic gas sensitive test system for aging treatment, the temperature is 250℃, and the time is 24h, to obtain a YbFeO3-BiFeO3 acetone gas sensor.

[0073] Example 3

[0074] The preparation process of the YbFe03-BiFe03 acetone gas sensor in this embodiment 3 refers to embodiment 1, except that 3wt.% Yb203 and BiFe03 powders are uniformly mixed, and then calcined at 700°C for 4h; the obtained composite material is placed in a 2mol / L HNO3 solution, and stirred uniformly by a magnetic stirrer; the above powders are washed several times with deionized water and anhydrous ethanol, and then dried at 70°C for 24h to obtain a pure phase YbFe03-BiFe03 composite material; the content of YbFe03 in the YbFe03-BiFe03 composite material is 4.0wt.%.

[0075] Embodiment 4

[0076] The preparation process of the YbFe03-BiFe03 acetone gas sensor in this embodiment 4 refers to embodiment 1, except that 5wt.% Yb203 and BiFe03 powders are uniformly mixed, and then calcined at 700°C for 4h; the obtained composite material is placed in a 2mol / L HNO3 solution, and stirred uniformly by a magnetic stirrer; the above powders are washed several times with deionized water and anhydrous ethanol, and then dried at 70°C for 24h to obtain a pure phase YbFe03-BiFe03 composite material; the content of YbFe03 in the YbFe03-BiFe03 composite material is 6.7wt.%.

[0077] Embodiment 5

[0078] The preparation process of the YbFe03-BiFe03 acetone gas sensor in this embodiment 5 refers to embodiment 1, except that 10wt.% Yb203 and BiFe03 powders are uniformly mixed, and then calcined at 750°C for 4h; the obtained composite material is placed in a 2mol / L HNO3 solution, and stirred uniformly by a magnetic stirrer; the above powders are washed several times with deionized water and anhydrous ethanol, and then dried at 70°C for 24h to obtain a pure phase YbFe03-BiFe03 composite material; the content of YbFe03 in the YbFe03-BiFe03 composite material is 13.4wt.%. Figure 8 The response and recovery curve of the YbFe03-BiFe03 sensor prepared in embodiment 5 to 10ppm acetone at a working temperature of 220°C; from the figure, it can be known that the response of the YbFe03-BiFe03 sensor to 10ppm acetone can reach 30.3.

[0079] Embodiment 6

[0080] The preparation process of the YbFe03-BiFe03 acetone gas sensor in this embodiment 6 refers to embodiment 1, except that 15wt.% Yb203 and BiFe03 powders are uniformly mixed, and then calcined at 700°C for 4h; the obtained composite material is placed in a 2mol / L HNO3 solution, and stirred uniformly with a magnetic stirrer; the above powders are washed with deionized water and anhydrous ethanol for several times, and then dried at 70°C for 24h to obtain a YbFe03-BiFe03 composite material; the content of YbFe03 in the YbFe03-BiFe03 composite material is 20.1wt.%.

[0081] Comparative example 1

[0082] An acetone sensor is prepared by using pure BiFe03 as a sensitive material, and the specific process is as follows:

[0083] (1) Take iron nitrate nonahydrate and bismuth nitrate pentahydrate with a molar ratio of 1:1, and add them to a dilute nitric acid solution with a concentration of 2mol / L, and continuously stir until completely dissolved;

[0084] (2) Add 12mol / L potassium hydroxide for reaction, adjust the solution pH to 14, and centrifuge and wash the obtained reaction product;

[0085] (3) Add the reaction product prepared in step (2) to a 12mol / L potassium hydroxide and 2mol / L potassium nitrate aqueous solution, stir uniformly, and then transfer to a hydrothermal kettle for reaction, with a hydrothermal time of 24h and a hydrothermal temperature of 180°C. After centrifugation, washing and drying, BiFe03 powder is obtained;

[0086] (4) Mix 10mg BiFe03 powder with 20μL terpineol, grind uniformly to obtain a slurry with appropriate viscosity, and then use screen printing technology to coat it on one side of an Al203 ceramic sheet with Au interdigital electrodes, with a film thickness of 60μm;

[0087] (5) Place the sensitive film prepared in step (4) in an oven and dry at 250°C for 6h, and then weld the pins of the sensor on the device base;

[0088] (6) Place the sensor prepared in step (5) in a dynamic gas sensitive test system for aging treatment, with a temperature of 250°C and a time of 24h, to obtain an acetone gas sensor based on BiFe03 material.

Claims

1. An acetone gas-sensitive material, characterized in that: The acetone gas-sensitive material is composed of a YbFeO3-BiFeO3 composite material, and a pp heterojunction is formed between YbFeO3 and BiFeO3.

2. The acetone gas-sensitive material according to claim 1, characterized in that: The content of YbFeO3 in the YbFeO3-BiFeO3 composite material is 1 to 25 wt.%.

3. The acetone gas-sensitive material according to claim 2, characterized in that: The content of YbFeO3 in the YbFeO3-BiFeO3 composite material is 5 to 20 wt%.

4. The acetone gas-sensitive material according to claim 3, wherein: The content of YbFeO3 in the YbFeO3-BiFeO3 composite material is 6 to 16 wt.%.

5. The acetone gas-sensitive material according to claim 4, wherein: The content of YbFeO3 in the YbFeO3-BiFeO3 composite material is 10-14 wt.%.

6. The acetone gas-sensitive material according to claim 1, wherein The particle size of the YbFeO3-BiFeO3 composite material is 0.2-5 μm.

7. The acetone gas-sensitive material according to claim 6, wherein: The particle size of the YbFeO3-BiFeO3 composite material is 0.2-1 μm.

8. A method for preparing an acetone gas-sensitive material according to any one of claims 1 to 7, characterized in that: include: 1) Mix Yb2O3 powder and BiFeO3 powder and calcine at 650-750℃ for 3-5 hours to obtain calcined powder; 2) The obtained calcined powder is placed in a nitric acid solution and stirred, and then washed and dried to obtain the YbFeO3-BiFeO3 composite material.

9. The preparation method according to claim 8, wherein The mass of the Yb2O3 powder is 1 to 15 wt.% of the mass of the BiFeO3 powder; The concentration of the nitric acid solution is 1 to 3 mol / L; The stirring process is performed at a rotation speed of 600 to 800 rpm and for a time of 0.5 to 2 h.

10. An acetone gas sensor based on YbFeO3-BiFeO3 composite material, characterized in that: include: A YbFeO3-BiFeO3 sensitive film prepared from the acetone gas-sensitive material according to any one of claims 1 to 7.

11. The acetone gas sensor based on the YbFeO3-BiFeO3 composite material according to claim 10, characterized in that: include: A substrate, an interdigital electrode and a YbFeO3-BiFeO3 sensitive film formed on the surface of one side of the substrate, and a heating electrode formed on the surface of the other side of the substrate.

12. The acetone gas sensor based on the YbFeO3-BiFeO3 composite material according to claim 11, characterized in that: The thickness of the YbFeO3-BiFeO3 sensitive film is 40-80 μm.

13. The acetone gas sensor based on the YbFeO3-BiFeO3 composite material according to claim 11, characterized in that: The interdigital electrodes are composed of Au, Cr or Ag-Pd; the heating electrodes are composed of Pt, Cu or Ni-Cr; and the substrate is composed of A2O3 or Si.

14. The acetone gas sensor based on the YbFeO3-BiFeO3 composite material according to claim 11, characterized in that: In the detection of acetone gas, the optimal operating temperature of the acetone gas sensor based on YbFeO3-BiFeO3 composite material is ≤200 ℃, and the response to 10 ppm acetone at the optimal operating temperature is as high as 32.

6.

15. A method for preparing an acetone gas sensor based on a YbFeO3-BiFeO3 composite material according to any one of claims 11 to 14, characterized in that: The preparation method of the YbFeO3-BiFeO3 sensitive film comprises: (1) dispersing the YbFeO3-BiFeO3 composite material in an organic solvent to obtain a slurry; (2) The obtained slurry is coated on the surface of the interdigital electrode, and then dried and aged to obtain a YbFeO3-BiFeO3 sensitive film.

16. The preparation method according to claim 15, characterized in that The ratio of the YbFeO3-BiFeO3 composite material to the organic solvent is (10-20) mg: (15-30) μL; the organic solvent is at least one of terpineol, ethanol, acetone and glycerol.

17. The preparation method according to claim 15, characterized in that The coating method is screen printing; The drying temperature is 200-300°C and the drying time is 4-12 hours; The aging treatment is carried out at a temperature of 200 to 300° C. and for a time of 24 to 48 hours.

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