Zinc metaniobate composite material, preparation method and application thereof

Abstract

The application relates to the technical field of sensors, in particular to a zinc metatungstate composite material and a preparation method and application thereof. The composite material is a zinc metatungstate composite material doped with Bi2O3 and Sb2O3, the specific surface area of the composite material is large, the surface active sites are many, and the pore structure is rich, the composite material has high responsiveness to VOCs gas as a gas-sensitive material, and the stability is good.

Description

Technical Field

[0001] This invention relates to the field of sensor technology, and in particular to a zinc stannate composite material, its preparation method, and its application. Background Technology

[0002] Currently, sensors used for VOCs gas detection mainly fall into two categories: electrochemical sensors and semiconductor sensors. Semiconductor sensors, in particular, are gaining more attention due to their smaller size, lower cost, and lower power consumption. Commercially available semiconductor sensors include planar semiconductor sensors and MEMS semiconductor sensors, with the latter gradually replacing the former due to their lower power consumption. In the development and application of MEMS semiconductor sensors, their gas-sensing performance is limited by the specific surface area and structure of the gas-sensing material. Research shows that a larger specific surface area provides more surface active centers for the gas-sensing reaction, and the special structure of porous materials is more conducive to gas penetration through the material surface into the material's interior for gas-sensing reactions. Changes in internal and external electron concentrations cause more significant changes in resistance, thus being more beneficial for VOCs gas monitoring.

[0003] Zinc metastannate (ZnSnO3) is a typical rare earth composite metal oxide with a perovskite (ABO3) structure. Due to its stable crystal structure, non-toxicity, and small band gap energy, ZnSnO3 has attracted much attention as a gas-sensitive material. However, gas sensors made of pure ZnSnO3 have drawbacks such as low VOCs response value and poor response stability, which urgently need to be improved. Summary of the Invention

[0004] Based on this, the present invention provides a zinc metastannate composite material, which has excellent gas sensitivity, high responsiveness to VOCs gases, and good stability.

[0005] The technical solution of the present invention is as follows:

[0006] A zinc stannate composite material, wherein the composite material is a zinc stannate composite material doped with Bi2O3 and Sb2O3.

[0007] In some embodiments, the composite material comprises 1% to 4% Bi2O3 and 0.5% to 2% Sb2O3 by mass percentage.

[0008] A method for preparing a zinc metastannate composite material includes the following steps:

[0009] A mixture of tin salts, zinc salts, bismuth salts, and antimony salts is prepared.

[0010] A precipitant is added to the mixture, and a zinc hydroxystannate precursor is prepared by hydrothermal reaction;

[0011] The precursor is subjected to sintering treatment.

[0012] In some embodiments of the preparation method, the molar ratio of the tin salt, zinc salt and precipitant is 3:3:(20~30);

[0013] The concentration of the precipitant is 0.2 mol / L to 0.4 mol / L.

[0014] In some embodiments of the preparation method, the molar ratio of the tin salt to the bismuth salt is 1:(0.02~0.04).

[0015] The molar ratio of the tin salt to the antimony salt is 1:(0.008~0.26).

[0016] In some embodiments of the preparation method, the tin salt includes one or more of SnCl4·5H2O and Sn(NO3)4.

[0017] In some embodiments of the preparation method, the zinc salt includes one or more of Zn(NO3)2·6H2O, Zn(CH3COO)2·2H2O, and ZnSO4.

[0018] In some embodiments of the preparation method, the bismuth salt includes one or more of Bi(NO3)3 and BiCl3.

[0019] In some embodiments of the preparation method, the antimony salt includes one or more of SbCl3 and Sb(NO3)3.

[0020] In some embodiments of the preparation method, the precipitant includes one or more of ammonia, urea, sodium hydroxide, and potassium hydroxide.

[0021] In some embodiments of the preparation method, the hydrothermal reaction temperature is 130°C to 150°C.

[0022] In some embodiments of the preparation method, the hydrothermal reaction time is 12h~16h.

[0023] In some embodiments of the preparation method, the heating rate of the sintering treatment is 4℃ / min to 6℃ / min.

[0024] In some embodiments of the preparation method, the sintering temperature is 400℃~600℃.

[0025] In some embodiments of the preparation method, the sintering time is 1h to 3h.

[0026] A gas-sensitive material, wherein the gas-sensitive material comprises the above-mentioned zinc stannate composite material or the zinc stannate composite material prepared by the above-mentioned preparation method.

[0027] A gas-sensitive sensor, the gas-sensitive sensor comprising the aforementioned gas-sensitive material.

[0028] The present invention has the following beneficial effects:

[0029] (1) The zinc stannate composite material prepared by Bi2O3 and Sb2O3 doping zinc stannate in this invention has a large specific surface area, many surface active sites, and rich pore structure. It has high responsiveness to VOCs gas and good stability when used as a gas-sensitive material.

[0030] (2) The zinc stannate composite material of the present invention can be prepared by a simple hydrothermal method, and the raw materials used are simple and easy to obtain, the production cost is lower, and it is easy to promote and use on a large scale. Attached Figure Description

[0031] Figure 1 Scanning electron microscope image of Bi2O3(3wt%)-Sb2O3(1wt%)-ZnSnO3 prepared in Example 1;

[0032] Figure 2 The figures show the stability test results of the gas-sensitive materials in the examples and comparative examples. Detailed Implementation

[0033] To facilitate understanding of the present invention, a more complete description will be given below with reference to the accompanying drawings. Preferred embodiments of the invention are shown in the drawings. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the invention.

[0034] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0035] Studies have shown that a larger specific surface area provides more surface active centers for gas-sensitive reactions. The special structure of porous structures is more conducive to gas transmission through the material surface into the material interior for gas-sensitive reactions. Changes in internal and external electron concentrations cause more significant changes in resistance, thus making them more suitable for VOCs gas monitoring. Extensive research has been conducted on the gas-sensitive properties of zinc stannate materials. For example, Song Peng et al. studied a method for preparing hollow tetrahedral zinc hydroxystannate gas-sensitive materials using a self-sacrificial template method; Shu Shaoming et al. synthesized hollow cubic zinc stannate using a simple one-step co-precipitation method; Liu Jianhua et al. prepared three nano-zinc stannates with different morphologies under different conditions using a hydrothermal method. However, pure ZnSnO3 gas sensors suffer from low VOCs response values ​​and poor response stability. To improve the gas-sensitive performance of pure ZnSnO3 gas-sensitive materials, researchers have also studied methods such as doping modification or composite with other semiconductor materials. In doping studies, the use of noble metals and rare earth metals is a common method; however, the cost of doping with noble metals and rare earth metals is very high.

[0036] The present invention provides a zinc metastannate composite material, wherein the composite material is a zinc metastannate composite material doped with Bi2O3 and Sb2O3.

[0037] In some examples, the composite material comprises 1% to 4% Bi₂O₃ and 0.5% to 2% Sb₂O₃ by mass percentage. Preferably, the composite material comprises 2% to 3% Bi₂O₃ and 0.5% to 1.5% Sb₂O₃.

[0038] This invention relates to a zinc stannate composite material prepared by doping zinc stannate with Bi₂O₃ and Sb₂O₃. This composite material has a large specific surface area, numerous surface active sites, and abundant porous structure, which facilitates the entry of VOCs gas into the interior of the composite material, forming an electron depletion layer inside, which, combined with an external electron depletion layer, results in a higher gas-sensing response value. Moreover, compared to the traditional method of doping with rare earth metals and noble metals, this invention uses Bi₂O₃ and Sb₂O₃ for doping, requiring inexpensive raw materials and resulting in lower preparation costs.

[0039] A method for preparing a zinc metastannate composite material includes the following steps:

[0040] S110: Prepare a mixed solution by mixing tin salt, zinc salt, bismuth salt and antimony salt.

[0041] In some of these examples, the tin salt includes one or more of SnCl4·5H2O and Sn(NO3)4.

[0042] In some of these examples, the zinc salt comprises one or more of Zn(NO3)2·6H2O, Zn(CH3COO)2·2H2O, and ZnSO4.

[0043] In some of these examples, the bismuth salt includes one or more of Bi(NO3)3 and BiCl3.

[0044] In some of these examples, the antimony salt includes one or more of SbCl3 and Sb(NO3)3.

[0045] In some of these examples, the tin salt, zinc salt, bismuth salt, and antimony salt are added to an acidic solution and mixed thoroughly under magnetic stirring conditions. The magnetic stirring rate is 400 rad / min to 500 rad / min, and the stirring time is 1 h to 3 h.

[0046] In some examples, the acidic solution is a hydrochloric acid solution or a nitric acid solution with a pH of 2 to 3.

[0047] Understandably, the hydrolysis of tin salts can be effectively inhibited in the acidic solution with a pH of 2-3.

[0048] S210: Add a precipitant to the mixture and prepare zinc hydroxystannate precursor by hydrothermal reaction.

[0049] In some of these examples, the precipitant includes one or more of ammonia, urea, sodium hydroxide, and potassium hydroxide.

[0050] In some of these examples, the molar ratio of the tin salt, zinc salt, and precipitant is 3:3:(20~30).

[0051] In some of these examples, the concentration of the precipitant is 0.2 mol / L to 0.4 mol / L.

[0052] In some of these examples, the molar ratio of the tin salt to the bismuth salt is 1:(0.02~0.04).

[0053] The molar ratio of the tin salt to the antimony salt is 1:(0.008~0.26).

[0054] In some of these examples, the precipitant is added dropwise to the mixture under magnetic stirring, with the dropping rate controlled at 1 mL / min to 5 mL / min.

[0055] In some specific examples, the precipitant is added dropwise to the mixture while the magnetic stirring rate is 550 rad / min to 700 rad / min and the stirring time is 1 h to 3 h.

[0056] In the preparation of zinc metastannate, the precipitant is added slowly to prevent local supersaturation of the solution, thereby obtaining a precipitate with finer particles and higher purity. Moreover, too rapid a dropping rate may lead to excessively high local concentrations, increasing the possibility of hydrolysis of the precipitate.

[0057] In some of these examples, the hydrothermal reaction temperature is 130°C to 150°C.

[0058] In some of these examples, the hydrothermal reaction time is 12 to 16 hours.

[0059] The following reaction occurs during this step:

[0060] Sn 4+ + Zn 2+ +6OH - →ZnSn(OH)6;

[0061] Bi 3+ + 3OH - →Bi(OH)3↓;

[0062] Sb 3+ + 3OH - →Sb(OH)3↓.

[0063] In some of these examples, the process of washing and drying the zinc hydroxystannate precursor is included after the hydrothermal reaction.

[0064] In some of these examples, deionized water and anhydrous ethanol were used for washing, specifically by washing 2 to 3 times in a high-speed benchtop centrifuge, with the centrifuge speed set at 7000 rad / min to 7500 rad / min and the time set at 4 min to 6 min.

[0065] In some examples, the drying temperature is 50°C to 80°C, for example, 50°C, 60°C, 70°C or 80°C, preferably 60°C. The drying time is 23h to 28h, for example, 23h, 24h, 25h, 26h, 27h or 28h, preferably 24h.

[0066] S310: The precursor is subjected to sintering treatment.

[0067] In some of these examples, the heating rate of the sintering process is 4°C / min to 6°C / min, for example, 4°C / min, 5°C / min or 6°C / min, preferably 5°C / min.

[0068] In some of these examples, the sintering temperature is 400°C to 600°C, for example, 400°C, 450°C, 500°C or 600°C, preferably 450°C.

[0069] In some of these examples, the sintering time is 1 to 3 hours, for example, 1 hour, 2 hours or 3 hours, preferably 2 hours.

[0070] The following reaction occurs during this step:

[0071] ZnSn(OH)6→ZnSnO3+3H2O;

[0072] 2Bi(OH)3→Bi2O3+3H2O;

[0073] 2Sb(OH)3→Sb2O3+3H2O.

[0074] In some of these examples, the sintering process is followed by ball milling and drying.

[0075] In some of these examples, ball milling is performed by dispersing the sintered material in anhydrous ethanol.

[0076] In some of these examples, the ball milling rate is 1100 rad / min to 1400 rad / min, for example, 1100 rad / min, 1200 rad / min, 1300 rad / min or 1400 rad / min, preferably 1200 rad / min.

[0077] In some of these examples, the ball milling time is 6h to 10h, for example, 6h, 7h, 8h, 9h or 10h, preferably 8h.

[0078] In some examples, the drying temperature is 50°C to 80°C, for example, 50°C, 60°C, 70°C or 80°C, preferably 60°C. The drying time is 23h to 28h, for example, 23h, 24h, 25h, 26h, 27h or 28h, preferably 24h.

[0079] A gas-sensitive material, wherein the gas-sensitive material comprises the above-mentioned zinc stannate composite material or the zinc stannate composite material prepared by the above-mentioned preparation method.

[0080] In some more specific examples, the gas-sensitive material of the present invention is a zinc metastannate composite material doped with Bi2O3 and Sb2O3 obtained by the above preparation method.

[0081] Because of its large ionic radius, bismuth doping into the ZnSnO3 matrix easily causes lattice distortion, leading to numerous crystal defects and thus enhancing the gas-sensing properties of the material. Furthermore, due to the large ionic radius of bismuth, doping can increase the surface activity of the material, thereby increasing the number of active sites on which gas molecules depend for chemical reactions. In addition, because bismuth is chemically stable, doping can reduce performance fluctuations of the material under complex environments, thereby improving the stability and reliability of the gas-sensing performance. Therefore, choosing to dope bismuth into gas sensors based on ZnSnO3 will greatly improve the gas-sensing performance of the gas-sensitive material.

[0082] When antimony enters the zinc stannate lattice, its outer electron structure differs from the matrix material, forming impurity energy levels. These impurity energy levels can act as traps or release centers for charge carriers, affecting their migration and transport characteristics. Since antimony has a higher atomic number than tin, the impurity energy levels formed after doping are lower than the Fermi level of the matrix, which facilitates carrier migration and transport. On the other hand, antimony also forms positively charged centers in the zinc stannate lattice. These centers can attract negative ions or electrons, forming ion pairs or electron pairs, thereby increasing the number and concentration of charge carriers. These additional charge carriers enhance current conduction. Antimony can also alter the surface chemistry of zinc stannate, increasing its chemisorption of target gases. Chemisorption can lead to charge transfer or chemical bonding, further enhancing the capture and release of charge carriers. The combined effect of these reaction mechanisms reduces the resistance of the gas-sensitive material, making it more sensitive and faster to gas reactions. Especially during long-term use, lower resistance reduces errors caused by factors such as temperature and humidity, improving measurement accuracy.

[0083] A gas-sensitive sensor, the gas-sensitive sensor comprising the aforementioned gas-sensitive material.

[0084] The embodiments of the present invention will be described in detail below with reference to examples. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. For experimental methods in the following embodiments where specific conditions are not specified, please refer to the guidelines given in this invention, or follow experimental manuals or conventional conditions in the art, or follow the conditions recommended by the manufacturer, or refer to experimental methods known in the art.

[0085] In the specific embodiments described below, the measurement parameters involving raw material components may have slight deviations within the weighing accuracy range unless otherwise specified. Temperature and time parameters are subject to acceptable deviations due to instrument testing accuracy or operational precision.

[0086] The raw materials and reagents information in this embodiment of the invention are as follows: unless otherwise specified, all raw materials are of analytical grade.

[0087] SnCl4·5H2O (Shanghai Maclean Biotechnology Co., Ltd., analytical grade);

[0088] Zn(NO3)2·6H2O (Shanghai Maclean Biotechnology Co., Ltd., analytical grade);

[0089] Bi(NO3)3 (Shanghai Maclean Biotechnology Co., Ltd., analytical grade);

[0090] SbCl3 (Shanghai Maclean Biotechnology Co., Ltd., analytical grade);

[0091] Ammonia water (Shanghai Maclean Biotechnology Co., Ltd., 25%-28%)

[0092] Glycerol (Shanghai Maclean Biotechnology Co., Ltd., 25%-28%)

[0093] Ethylene glycol (Shanghai Maclean Biotechnology Co., Ltd., 25%-28%)

[0094] Anhydrous ethanol (Tianjin Kemio Chemical Reagent Co., Ltd., analytical grade);

[0095] MEMS gas-sensitive chip gas-sensitive electrode (Suzhou Sinan Sensing Technology Co., Ltd. 1×1×0.5mm).

[0096] Example 1

[0097] 1. Preparation of zinc hydroxystannate precursor

[0098] (1) Prepare 90 mL of hydrochloric acid solution with pH 2-3. After completion, seal the opening with plastic wrap and label it as solution A;

[0099] (2) Weigh 1.05g SnCl4·5H2O; 0.863g Zn(NO3)2·6H2O; according to mass percentage, the dopant content is 3wt% Bi2O3 and 1wt% Sb2O3, the required Bi(NO3)3 is 0.0375g, and the required SbCl3 is 0.0115g. Add the weighed SnCl4·5H2O, Zn(NO3)2·6H2O, Bi(NO3)3 and SbCl3 to solution A respectively under magnetic stirring. The magnetic stirring speed is set to 450rad / min and the stirring time is set to 1h. After completion, seal with plastic wrap and label as solution B.

[0100] (3) Measure 16.5 mL of ammonia solution and add it dropwise into solution B. The stirring rate is set to 600 rad / min and the stirring time is set to 1 h. After completion, seal the solution with plastic wrap and label it as suspension C.

[0101] (4) Transfer the suspension C to a polytetrafluoroethylene reactor and react it in an oven at 140°C for 12 hours. After the reaction is complete, cool it, let it stand, and collect the precipitate.

[0102] 2. Zinc hydroxystannate washing

[0103] The precipitate was washed three times with deionized water and anhydrous ethanol in a high-speed benchtop centrifuge. The centrifuge speed was set to 7000 rad / min and the time was set to 5 min.

[0104] 3. Drying zinc hydroxystannate

[0105] After washing, the precipitate was dried in an oven at 60°C for 24 hours to obtain zinc hydroxystannate, a precursor of zinc metastannate.

[0106] 4. High-temperature sintering of zinc hydroxystannate

[0107] White zinc hydroxystannate powder was sintered in a muffle furnace at a temperature of 450°C for 2 hours and a heating rate of 5°C / min to obtain white zinc metastannate powder.

[0108] 5. Ball-milled zinc metastannate

[0109] Zinc metastannate powder was dispersed in anhydrous ethanol and ball-milled in a ball mill at a rate of 1200 rad / min for 8 hours.

[0110] 6. Drying zinc metastannate

[0111] After ball milling, zinc stannate was dried in an oven at 60°C for 24 hours to obtain bismuth / antimony-doped zinc stannate gas-sensitive material Bi2O3(3%)-Sb2O3(1%)-ZnSnO3.

[0112] 7. Weigh 0.5g of the above gas-sensitive material and disperse it in a mixture of 1.5g of ethylene glycol and glycerol in a volume ratio of 1:4. Grind the mixture thoroughly in a ball mill to obtain a gas-sensitive slurry. Apply the slurry evenly to the surface of the gas-sensitive electrode of the MEMS gas-sensitive chip and heat-treat it at 550℃ for 2 hours at a heating rate of 5℃ / min. After heat treatment, encapsulate and wire bond the slurry, cap it, and finally introduce it into the test circuit. After aging until the resistance value stabilizes, introduce the test gas to test the gas-sensitive performance.

[0113] Figure 1 The scanning electron microscope (SEM) image of Bi₂O₃(3%)-Sb₂O₃(1%)-ZnSnO₃ prepared in Example 1 is shown below. Figure 1 As can be seen from the data, the gas-sensitive material prepared in Example 1 has the characteristics of being hollow and having a porous surface, with a size of approximately 500 nm.

[0114] Example 2

[0115] The preparation method of Example 2 is basically the same as that of Example 1, except that the doping amount of Example 2 is 2% Bi2O3 and 1% Sb2O3.

[0116] Example 3

[0117] The preparation method of Example 3 is basically the same as that of Example 1, except that the doping amount of Example 3 is 1% Bi2O3 and 1% Sb2O3.

[0118] Example 4

[0119] The preparation method of Example 4 is basically the same as that of Example 1, except that the doping amount of Example 4 is 4% Bi2O3 and 1% Sb2O3.

[0120] Example 5

[0121] The preparation method of Example 5 is basically the same as that of Example 1, except that the doping amount of Example 5 is 3% Bi2O3 and 0.5% Sb2O3.

[0122] Example 6

[0123] The preparation method of Example 6 is basically the same as that of Example 1, except that the doping amount of Example 6 is 3% Bi2O3 and 1.5% Sb2O3.

[0124] Example 7

[0125] The preparation method of Example 6 is basically the same as that of Example 1, except that the doping amount of Example 6 is 3% Bi2O3 and 2% Sb2O3.

[0126] Comparative Example 1

[0127] The preparation method of Comparative Example 1 is basically the same as that of Example 1, except that the dopant in Comparative Example 1 does not contain Sb. After completion, the slurry is prepared in the same way as in Example 1, the sensor is prepared and the gas sensing performance is tested.

[0128] Comparative Example 2

[0129] The preparation method of Comparative Example 2 is basically the same as that of Example 1, except that the Sb in Comparative Example 2 is replaced with Cr, which is a different element. 3+ Instead, the slurry was prepared using the same method as in Example 1, the sensor was fabricated, and its gas-sensing performance was tested.

[0130] Test case

[0131] The sensors prepared in the above embodiments and comparative examples were subjected to performance tests.

[0132] 1. Resistance performance test

[0133] The testing method is as follows: After the MEMS gas-sensitive chip undergoes heat treatment, the resistance between the two pins connected to the gas-sensitive electrode on the back of the chip is measured using a multimeter to represent the resistance of the gas-sensitive material at room temperature. The results are shown in Table 1 below:

[0134] Table 1

[0135]

[0136] As shown in Table 1, gas-sensitive materials doped with both bismuth and antimony have lower initial resistance; gas-sensitive materials doped with only bismuth have higher initial resistance.

[0137] 2. Response speed test

[0138] The test method is as follows: The sensor is placed in a gas test chamber, and a certain volume of volatile liquid (100ppm alcohol was used in this test at 25℃ and 50% RH) is injected through the gas inlet of the test chamber. Heating and a fan are used to rapidly diffuse the volatile liquid. After the sensor resistance stabilizes at this concentration, the chamber door is opened, and the sensor resistance is allowed to return to its initial state. The change in sensor resistance during this process is recorded. The time it takes for the sensor to change from its initial resistance to 90% of its stable resistance at that concentration after a certain concentration of test gas is introduced is defined as T. 90 The results are shown in Table 2 below:

[0139] Table 2

[0140]

[0141] Table 2 shows that the gas-sensitive materials doped with both bismuth and antimony exhibit a faster response rate to ethanol. The gas-sensitive materials show superior response speed performance when the doping concentration of Bi₂O₃ is 2%–3% and the doping concentration of Sb₂O₃ is 0.5%–1.5%.

[0142] 3. Stability Test

[0143] The test method is the same as the response speed test method in section 2. The test period is 150 days, with a test interval of 30 days per test. Record the sample sensitivity value for each test. Figure 2 As shown. From Figure 2 It can be seen that the gas-sensitive materials prepared in the above embodiments and comparative examples maintain good gas-sensing stability during the 150-day testing period. This indicates that the gas-sensing stability of the zinc stannate gas-sensitive material doped with Bi2O3 is good.

[0144] 4. Sensitivity Test

[0145] The test method is the same as in 2, defining the initial resistance R0 and the stable resistance R at a certain concentration of test gas after the sensor is introduced. g The ratios are shown in Table 3 below:

[0146] Table 3

[0147]

[0148] As shown in Table 3, the Bi2O3 and Sb2O3-doped zinc stannate composite material prepared in this invention has high ethanol sensitivity. When the doping amount of Bi2O3 is 2%~3% and the doping amount of Sb2O3 is 0.5%~1.5%, the ethanol sensitivity performance of the gas-sensitive material is better.

[0149] 5. VOCs detection performance

[0150] The sensitivity and response speed of the sensor for other VOCs gases were tested. The sensitivity test method was the same as in 4, and the results are shown in Table 4 below. The response speed test was the same as in 2, and the results are shown in Table 5 below.

[0151] Table 4

[0152]

[0153] Table 5

[0154]

[0155] As shown in Tables 4 and 5, the zinc metastannate composite material doped with Bi2O3 and Sb2O3 exhibits good sensitivity and response speed for most VOCs gases.

[0156] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0157] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A zinc metastannate composite material, characterized in that, The composite material is a zinc metastannate composite material doped with Bi2O3 and Sb2O3; by mass percentage, the composite material includes 2%~3% Bi2O3 and 0.5%~1.5% Sb2O3. The preparation method of the zinc stannate composite material includes the following steps: A mixture of tin salts, zinc salts, bismuth salts, and antimony salts is prepared. A precipitant is added to the mixture, and a zinc hydroxystannate precursor is prepared by hydrothermal reaction; The precursor is subjected to sintering treatment; The hydrothermal reaction temperature is 130℃~150℃.

2. A method for preparing the composite material according to claim 1, characterized in that, Includes the following steps: A mixture of tin salts, zinc salts, bismuth salts, and antimony salts is prepared. A precipitant is added to the mixture, and a zinc hydroxystannate precursor is prepared by hydrothermal reaction; The precursor is subjected to sintering treatment; the hydrothermal reaction temperature is 130℃~150℃.

3. The preparation method according to claim 2, characterized in that, The molar ratio of the tin salt, zinc salt and precipitant is 3:3:(20~30); The concentration of the precipitant is 0.2 mol / L to 0.4 mol / L.

4. The preparation method according to claim 2, characterized in that, The molar ratio of the tin salt to the bismuth salt is 1:(0.02~0.04). The molar ratio of the tin salt to the antimony salt is 1:(0.008~0.26).

5. The preparation method according to claim 2, characterized in that, Satisfy one or more of the following conditions (1) to (5): (1) The tin salt includes one or more of SnCl4·5H2O and Sn(NO3)4; (2) The zinc salt includes one or more of Zn(NO3)2·6H2O, Zn(CH3COO)2·2H2O and ZnSO4; (3) The bismuth salt includes one or more of Bi(NO3)3 and BiCl3; (4) The antimony salt includes one or more of SbCl3 and Sb(NO3)3; (5) The precipitant includes one or more of ammonia, urea, sodium hydroxide and potassium hydroxide.

6. The preparation method according to any one of claims 2 to 5, characterized in that, The hydrothermal reaction time is 12h~16h.

7. The preparation method according to any one of claims 2 to 5, characterized in that, The conditions for sintering include one or more of the following (1) to (3): (1) The heating rate is 4℃ / min to 6℃ / min; (2) The sintering temperature is 400℃~600℃; (3) The sintering time is 1h~3h.

8. A gas-sensitive material, characterized in that, The gas-sensitive material includes the zinc stannate composite material according to claim 1 or the zinc stannate composite material prepared by the preparation method according to any one of claims 2 to 7.

9. A gas-sensitive sensor, characterized in that, The gas sensor includes the gas-sensitive material as described in claim 8.

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