Low-temperature gas-sensitive material with In2O3 layer growing on ZnSnO3 surface and preparation method of low-temperature gas-sensitive material

Abstract

The invention relates to a low-temperature gas-sensitive material with an In2O3 layer grown on the surface of ZnSnO3 and a preparation method thereof, ZnSnO3 is Archimedes particles, three quadrilateral surfaces are arranged around each triangular surface in the multi-dimensional surfaces of the Archimedes, each quadrilateral surface and the triangular surface share the same edge, In2O3 nanoparticles uniformly grow on the multi-dimensional surfaces of the ZnSnO3 Archimedes particles, and the In2O3 nanoparticles are uniformly distributed on the multi-dimensional surfaces of the ZnSnO3 Archimedes particles. And a uniformly distributed In2O3 particle composite layer is formed. The method comprises the following steps: dissolving zinc oxalate into deionized water, adding tin chloride, adding sodium hydroxide particles, dropwise adding an indium nitrate solution, carrying out a hydrothermal reaction, centrifuging, washing, drying, and finally calcining. The ZnSnO3 / In2O3 composite material is higher in base resistance in air, high in sensitivity to ethylene glycol gas and triethylamine gas and low in working temperature. The method is low in preparation cost and has a good industrial application prospect.

Description

Technical Field

[0001] The present invention belongs to the technical field of metal oxide semiconductor nanomaterials and relates to a ZnSnO 3 Surface growth 2 O 3 Layered low-temperature gas-sensitive material and preparation method thereof. Background Art

[0002] The continuous development of industrial level has facilitated people's daily life, but at the same time, it has also brought increasingly serious environmental pollution, such as substandard industrial waste gas treatment, excessive emission of toxic and harmful gases, etc., which have had an adverse impact on people's health and living environment. In addition, the exhaust emissions of vehicles such as cars and ships, harmful gases produced by fuel combustion, and volatile organic compounds can also endanger human health. With the improvement of citizens' environmental awareness, people have higher and higher requirements for the detection of toxic, harmful, flammable and explosive gases. Therefore, research and development of ZnSnO with high sensitivity to harmful gases, low optimal operating temperature, good stability and selectivity is needed. 3 Gas sensors have become one of the current research hotspots.

[0003] From the adsorption-desorption detection mechanism of the gas sensor, we know that ZnSnO 3 The gas sensing performance of the material is closely related to its structure, specific surface area, pore quantity and size distribution. 3 To solve the problem of high working temperature of gas-sensitive materials, people mainly improve the performance of ZnSnO by adjusting microstructure, doping, loading precious metals and composite modification. 3 A large number of experimental studies have shown that composite modification can greatly improve the gas sensing performance of ZnSnO 3 Gas sensing performance. Common types of composite sensing materials include: composites of metal oxides and carbon materials (carbon nanotubes, graphene sheets, etc.), composites of metal oxides and noble metals (noble metals such as Pb and Pt loaded on metal substrates), composites of metal oxides and conductive polymer compounds (polyaniline, polyethylene, etc.), and composites of different metal oxides (for example, composites with NiO, ZnO, etc.). When two different materials are composited, a heterojunction will be formed at the interface where the two materials contact, accompanied by the transfer of electrons and the formation of a depletion layer until the Fermi levels of the two materials reach equilibrium. The reconstructed Fermi level can affect the amount of surface gas adsorption by adjusting the surface potential barrier, thereby greatly improving the sensitivity, selectivity, and stability of gas-sensitive materials and reducing the operating temperature. It should be pointed out that the existing research on ZnSnO 3 The composite modified materials focus on nanostructured carbon materials, precious metals and p-type metal oxides, while the ZnSnO 3 With low-cost n-type In 2 O 3There are very few reports on composite studies.

[0004] In addition, ZnSnO 3 As a typical perovskite-structured ternary metal oxide, the commonly reported rhombohedral ZnSnO 3 Most of them are hexahedral, with small specific surface area and underdeveloped pores. 3 The crystal structure characteristics of ZnSnO are a=b=c, α=β=γ≠90°. 3 The surface energy of each crystal plane is (110)>(100)>(111). Stable crystal structures often have the smallest surface energy. 3 The stable plane is (111). The (110) and (100) crystal planes with higher surface energy will gradually disappear during the crystal growth process, forming a stable structure. However, only the exposure of high surface energy active surfaces can provide more active sites for gas-sensitive chemical reactions, thereby improving the gas-sensitive performance of the material. Therefore, it is necessary to explore ZnSnO that can expose multiple high-active surfaces. 3 The preparation method and multi-directional crystal surface control technology are used to improve the sensitivity of the gas sensor while reducing the operating temperature and extending the service life.

[0005] So far, Archimedean ZnSnO with multidimensional surfaces has been obtained by one-step hydrothermal method. 3 For substrate growth In 2 O 3 There are no reports on the research of nanoparticles forming composite materials. In addition, few studies have been able to achieve low-temperature detection of two different gases on the same metal oxide semiconductor sensor, so it is necessary to develop a high-exposure multi-directional active surface ZnSnO 3 Materials and n-type In 2 O 3 Advantages of ZnSnO 3 / In 2 O 3 The composite material preparation method is intended to control the detection working temperature of ethylene glycol target gas at about 100°C, control the detection working temperature of triethylamine target gas at about 180°C, and enhance the response sensitivity. Summary of the invention

[0006] Purpose of the Invention

[0007] To solve the existing technology in ZnSnO 3 The problems of poor exposure of high surface energy active surface, small specific surface area and underdeveloped pores in the material preparation process, as well as the existing ZnSnO 3Gas-sensitive detection temperature is high (usually above 200°C), the composite modified material is expensive, the composite technology is complex and most of them are composited with p-type metal oxide semiconductors. The present invention provides a ZnSnO 3 Surface growth 2 O 3 The Archimedean ZnSnO was obtained by a simple one-step hydrothermal method. 3 Surface growth 2 O 3 The low-temperature gas-sensitive composite material of the layer can effectively simplify the composite process and reduce the working temperature of dual-gas gas-sensitive detection, and greatly improve the 3 sensitivity.

[0008] Technical Solution

[0009] A ZnSnO 3 Surface growth 2 O 3 Layer of low temperature gas sensitive material, ZnSnO 3 Archimedean particles have a particle size range of 500-900nm. In the multidimensional surface of the Archimedean body, each triangular face is surrounded by three quadrilateral faces, each quadrilateral face shares a side with the triangular face, and the length of each side ranges from 300-700nm. In particles with a particle size range of 5-50nm 2 O 3 Particles grown on ZnSnO 3 On the multidimensional surface of Archimedean particles, a uniform distribution of In 2 O 3 Particle composite layer.

[0010] Furthermore, ZnSnO 3 Surface growth 2 O 3 The powder particle size of the low-temperature gas-sensitive material of the layer is 0.7-1.5μm, In 2 O 3 Nanoparticle layers grow layer by layer along the multidimensional surface. 2 O 3 The thickness of the nanoparticle layer ranges from 200 to 600 nm, forming a nanoparticle layer covering a multi-dimensional surface of ZnSnO 3 / In 2 O 3 Composite structure; 2 O 3 When the thickness of the nanoparticle layer is greater than or equal to 200nm and less than 400nm, In 2 O 3 Particles along ZnSnO 3Archimedean bodies grow on multidimensional surfaces and maintain their morphology. 2 O 3 When the thickness of the nanoparticle layer is greater than or equal to 400nm and less than or equal to 600nm, ZnSnO is formed. 3 The base is an Archimedean body and In 2 O 3 Shell layer pelletized ZnSnO 3 / In 2 O 3 Low temperature gas sensitive composite material; ZnSnO 3 / In 2 O 3 The specific surface area of ​​the composite material is 42-65m 2 / g, containing micropores of 0.8-1.8nm and mesopores of 2.2-40nm

[0011] A ZnSnO as described 3 Surface growth 2 O 3 A method for preparing a low-temperature gas-sensitive material of a layer, the method steps are as follows:

[0012] Step 1: Dissolve zinc oxalate in deionized water at room temperature and stir to a concentration of 2.625-3.325 g / 100 mL. Add tin chloride during stirring. The molar ratio of zinc oxalate to tin chloride is 1:(1-1.1). Precipitate ZnSn(OH) 6 First granulate, stir and sieve to obtain solution A;

[0013] Step 2: Add sodium hydroxide particles with a particle size of 16-20 mesh to the solution A obtained in step 1, and the molar ratio of zinc oxalate to sodium hydroxide is 1:(9-12), and let it stand for 10-20 minutes to precipitate ZnSn(OH) 6 Secondary particles, introduction of ZnSn(OH) 6 The primary particles are then stirred for 10-20 minutes to obtain ZnSn(OH) 6 a suspension B of precursor particles;

[0014] Step 3, dissolving indium nitrate in deionized water to obtain an indium nitrate aqueous solution with a concentration of 0.1203-0.9024 g / 100 mL, the molar ratio of zinc oxalate to indium nitrate is 1:(0.02-0.15), and slowly dripping the indium nitrate aqueous solution into the suspension B obtained in step 2 at a rate of 0.08-0.2 mL / s at room temperature, stirring continuously at a speed of 700-1200 rpm for 0.5-1 h to obtain a white suspension C, and transferring the white suspension C to a reactor with a filling ratio of (1.75-1.9):5, hydrothermally reacting at a temperature of 80-120° C. and a pressure of 35-40 MPa for 8-12 h, and naturally cooling to room temperature to obtain a milky white suspension D;

[0015] Step 4: Transfer the milky white suspension D obtained in step 3 to a centrifuge for centrifugation at 3000-4500rpm, wash the white solid obtained by centrifugation with deionized water and ethanol alternately for 3-5 times, then place it in an oven at 60-75°C, dry it in an air atmosphere for 10-18h, place the dried powder in a muffle furnace, calcine it in an air atmosphere for 100-140min, start heating from room temperature, the heating rate is 2-5°C / min, the calcination temperature is 400-550°C, and finally obtain ZnSnO 3 Surface growth 2 O 3 layer of low-temperature gas-sensitive material. Further, the steps 1 and 2 are completed in a double-layer stirring device, which comprises an outer cylinder and an inner cylinder, wherein the inner cylinder is arranged on the inner side of the outer cylinder, a filter stirring assembly is arranged between the inner cylinder and the outer cylinder, the filter stirring assembly is fixed on the outer side of the inner cylinder, a fixed sleeve is arranged on the inner side of the inner cylinder, the bottom of the fixed sleeve is fixedly connected to the bottom of the outer cylinder, a stirring paddle is sleeved on the outer side of the fixed sleeve, a lifting mechanism is fixedly arranged inside the fixed sleeve, the telescopic end of the lifting mechanism is rotatably connected to the top of the inner cylinder, the top of the telescopic end of the lifting mechanism is fixedly connected to a connecting sleeve, a rotating cover is sleeved on the outer side of the connecting sleeve, the rotating cover is rotatably connected to the connecting sleeve, and the edge of the rotating cover is fixedly connected to the inner cylinder;

[0016] It also includes a first drive assembly and a second drive assembly. The second drive assembly is arranged at the top of the outer side of the fixed sleeve to provide power for the rotation of the stirring paddle; the first drive assembly is arranged at a side position of the telescopic end of the lifting mechanism to provide power for the rotation of the inner cylinder.

[0017] Furthermore, the filter assembly includes two support rods, both of which are fixed on the outside of the inner tube, the two support rods are arranged one above and one below, the angle between the two support rods is ninety degrees, and a filter net is fixedly connected between the two support rods.

[0018] Furthermore, the second driving component includes a second driving motor, which is fixedly connected to the outer top of the fixed sleeve, an outer gear ring is fixedly connected to the outer top of the stirring paddle, and a driving tooth is fixedly connected to the output end of the second driving motor. The second driving motor is meshed with the outer gear ring through the driving tooth at the output end.

[0019] Furthermore, the first driving component includes a driving motor 1, which is fixedly connected to the telescopic end of the lifting mechanism through a fixed frame, the bottom of the rotating cover is fixedly connected with an inner gear ring, the output end of the driving motor 1 is fixedly connected with driving teeth, and the driving teeth at the output end of the driving motor 1 are meshed with the inner side of the inner gear ring.

[0020] Furthermore, a discharge port is provided on one side of the outer cylinder, and an opening and closing door is provided at the discharge port.

[0021] Furthermore, in step 1, the outer cylinder and the inner cylinder are stirred and tin chloride is added, and the inner cylinder is driven to rotate by the first driving component, so that the liquid between the inner cylinder and the outer cylinder is stirred, and the ZnSn(OH) generated by hydrolysis is stirred by the filter stirring component. 6 The primary particles are stirred and screened, and the agglomerated particles will remain on the screen. Next, the lifting mechanism is started to push the rotating cover to drive the inner cylinder to move upward to achieve separation of the primary particles and the solution. Next, in step 2, sodium hydroxide particles are added to the inner cylinder. Next, downward ultrasound is applied to the top of the filter stirring component to vibrate the agglomerated particles away from the screen to achieve the introduction of the primary particles in step 2. Next, the second driving component drives the stirring paddle to rotate, so that the liquid is stirred for the second time by the stirring paddle.

[0022] Furthermore, the frequency of the ultrasound is 35-40 kHz, the ultrasound time is not less than 10 min, the stirring parameters in all steps are stirring at a speed of 700-1200 rpm for 0.5-1 h, and the mesh size of the filter is 7000 mesh.

[0023] Advantages and effects

[0024] (1) The preparation method of this patent can effectively realize the ZnSn(OH) 6 Primary particles and ZnSn(OH) generated by reaction with sodium hydroxide 6 The separation and synergistic effect of secondary particles are conducive to the uniform and fine precipitation of particles, and avoid the situation where the particle size is too large and the size difference is large due to the non-uniform nucleation of primary particles, ensuring the smallness and uniformity of the precursor suspension particles. Archimedean ZnSnO 3 The exposed highly active surface of the particles attracts In 2 O 3 Nanoparticle growth, forming uniform In on multidimensional surfaces 2 O3 The Archimedean body morphology is retained while the nanoparticle layer is formed. The Archimedean body morphology exposes more highly active surfaces, provides more reactive sites for gas-sensitive reactions, is beneficial to the adsorption and reaction of gases, and is a key factor in achieving improved gas-sensitive performance at low temperatures.

[0025] (2) Archimedean ZnSnO prepared by the present invention 3 Surface growth 2 O 3 Layered low-temperature gas-sensitive composite material based on Archimedean ZnSnO 3 As the base, In 2 O 3 Nanoparticles grown on Archimedean ZnSnO 3 A composite indium-containing layer is formed on the surface. 2 O 3 Nanoparticles and ZnSnO 3 The multi-dimensional surface of In is fully contacted to form an nn-type heterojunction. 2 O 3 The Fermi level of ZnSnO 3 , the electron will be 2 O 3 The conduction band of ZnSnO 3 The conduction band transfer of ZnSnO leads to the formation of an electron depletion layer and a contact barrier at the interface between the two. 3 / In 2 O 3 The composite material has higher base resistance in air and better gas sensing performance.

[0026] (3) The present invention adopts a one-step hydrothermal method and does not need to add a structure regulator. It can realize dual detection of ethylene glycol gas and triethylamine gas by adjusting the working temperature. When the working temperature is 100°C, the sensitivity of the composite material to 100ppm and 1ppm ethylene glycol can reach 3817 and 80 respectively; the sensitivity to 100ppm triethylamine reaches 2176, and the working temperature is 180°C. 3 Surface growth 2 O 3 The layered low-temperature gas-sensitive composite material has high sensitivity to ethylene glycol gas and triethylamine gas, low operating temperature and low preparation cost, and has good industrial application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The present invention is further described below in conjunction with the accompanying drawings and specific implementation methods. The protection scope of the present invention is not limited to the following description.

[0029] Figure 1 The ZnSnO prepared in Example 33 Surface growth 2 O 3 XRD pattern of the low-temperature gas-sensitive material of the layer;

[0030] Figure 2 The ZnSnO prepared in Example 3 3 Surface growth 2 O 3 Microscopic morphology of the low-temperature gas-sensitive material of the layer;

[0031] Figure 3 The ZnSnO prepared in Example 3 3 Surface growth 2 O 3 BJH adsorption and pore size distribution curves of low-temperature gas-sensitive materials of the layer;

[0032] Figure 4 The ZnSnO prepared in Example 3 3 Surface growth 2 O 3 The gas sensing performance diagram of the layer of low-temperature gas-sensitive material to ethylene glycol;

[0033] Figure 5 The ZnSnO prepared in Example 3 3 Surface growth 2 O 3 The gas sensing performance diagram of the layer of low-temperature gas-sensitive material to triethylamine;

[0034] Figure 6 The ZnSnO prepared in Example 4 3 Surface growth 2 O 3 Microscopic morphology of low-temperature gas-sensitive materials with a spheroidized outer shell layer;

[0035] Figure 7 It is a schematic diagram of the overall structure of a double-layer stirring device;

[0036] Figure 8 It is a cross-sectional view of the overall structure of the double-layer stirring device;

[0037] Fig. 9 It is a schematic diagram of the structure of the double-layer stirring device filtering assembly;

[0038] Fig.10 It is a schematic diagram of the connection structure between the lifting mechanism of the double-layer stirring device and the inner cylinder;

[0039] Fig.11 It is a structural schematic diagram of the first driving assembly of the double-layer stirring device;

[0040] Fig.12 It is a schematic diagram of the structure of the second driving component of the double-layer stirring device.

[0041] Description of reference numerals:

[0042] 1. Outer cylinder; 2. Inner cylinder; 3. Filter stirring assembly; 4. Fixed sleeve; 5. Stirring paddle; 6. First drive assembly; 7. Second drive assembly; 8. Support rod; 9. Filter; 10. Lifting mechanism; 11. Connecting sleeve; 12. Rotating cover; 13. Drive motor 1; 14. Inner gear ring; 15. Drive motor 2; 16. Outer gear ring; 17. Opening and closing door. DETAILED DESCRIPTION

[0043] The chemical reagents used in the embodiments of the present invention are all commercially available chemical reagents; the microscopic morphology detection in the embodiments of the present invention uses a SU-8010 field emission scanning electron microscope; the pore structure detection in the embodiments of the present invention uses a Vsorb 2800P specific surface area and pore size analyzer. The centrifuge in the embodiments of the present invention is a LDZ4-1.8 centrifuge; the lifting mechanism is a commercially available non-rotatable telescopic rod; the drive motor 1 and the drive motor 2 are commercially available conventional reduction motors.

[0044] A ZnSnO 3 Surface growth 2 O 3 Layer of low temperature gas sensitive material, ZnSnO 3 Archimedean particles have a particle size range of 500-900nm. In the multidimensional surface of the Archimedean body, each triangular face is surrounded by three quadrilateral faces, each quadrilateral face shares a side with the triangular face, and the length of each side ranges from 300-700nm. In particles with a particle size range of 5-50nm 2 O 3 Particles grown on ZnSnO 3 On the multidimensional surface of Archimedean particles, a uniform distribution of In 2 O 3 Particle composite layer.

[0045] Furthermore, ZnSnO 3 Surface growth 2 O 3 The powder particle size of the low-temperature gas-sensitive material of the layer is 0.7-1.5μm, In 2 O 3 Nanoparticle layers grow layer by layer along the multidimensional surface. 2 O 3 The thickness of the nanoparticle layer ranges from 200 to 600 nm, forming a nanoparticle layer covering a multi-dimensional surface of ZnSnO 3 / In 2 O 3 Composite structure; 2 O 3When the thickness of the nanoparticle layer is greater than or equal to 200nm and less than 400nm, In 2 O 3 Particles along ZnSnO 3 Archimedean bodies grow on multidimensional surfaces and maintain their morphology. 2 O 3 When the thickness of the nanoparticle layer is greater than or equal to 400nm and less than or equal to 600nm, ZnSnO is formed. 3 The base is an Archimedean body and In 2 O 3 Shell layer pelletized ZnSnO 3 / In 2 O 3 Low temperature gas sensitive composite material; ZnSnO 3 / In 2 O 3 The specific surface area of ​​the composite material is 42-65m 2 / g, containing micropores of 0.8-1.8nm and mesopores of 2.2-40nm.

[0046] A ZnSnO 3 Surface growth 2 O 3 A method for preparing a low-temperature gas-sensitive material of a layer, the method steps are as follows:

[0047] Step 1: Dissolve zinc oxalate in deionized water at room temperature and stir to a concentration of 2.625-3.325 g / 100 mL. Add tin chloride during stirring. The molar ratio of zinc oxalate to tin chloride is 1:(1-1.1). Precipitate ZnSn(OH) 6 First granulate, stir and sieve to obtain solution A;

[0048] Step 2: Add sodium hydroxide particles with a particle size of 16-20 mesh to the solution A obtained in step 1, and the molar ratio of zinc oxalate to sodium hydroxide is 1:(9-12), and let it stand for 10-20 minutes to precipitate ZnSn(OH) 6 Secondary particles, introduction of ZnSn(OH) 6 The primary particles are then stirred for 10-20 minutes to obtain ZnSn(OH) 6 a suspension B of precursor particles;

[0049] Step 3, dissolving indium nitrate in deionized water to obtain an indium nitrate aqueous solution with a concentration of 0.1203-0.9024 g / 100 mL, the molar ratio of zinc oxalate to indium nitrate is 1:(0.02-0.15), and slowly dripping the indium nitrate aqueous solution into the suspension B obtained in step 2 at a rate of 0.08-0.2 mL / s at room temperature, stirring continuously at a speed of 700-1200 rpm for 0.5-1 h to obtain a white suspension C, and transferring the white suspension C to a reactor with a filling ratio of (1.75-1.9):5, hydrothermally reacting at a temperature of 80-120° C. and a pressure of 35-40 MPa for 8-12 h, and naturally cooling to room temperature to obtain a milky white suspension D;

[0050] Step 4: Transfer the milky white suspension D obtained in step 3 to a centrifuge for centrifugation at 3000-4500rpm, wash the white solid obtained by centrifugation with deionized water and ethanol alternately for 3-5 times, then place it in an oven at 60-75°C, dry it in an air atmosphere for 10-18h, place the dried powder in a muffle furnace, calcine it in an air atmosphere for 100-140min, start heating from room temperature, the heating rate is 2-5°C / min, the calcination temperature is 400-550°C, and finally obtain ZnSnO 3 Surface growth 2 O 3 Layer of low-temperature gas-sensitive material.

[0051] like Figure 7 to Figure 12As shown, step one and step two are completed in a double-layer stirring device, which includes an outer cylinder 1 and an inner cylinder 2. A discharge port is provided on one side of the outer cylinder 1, and an opening and closing door 17 is provided on the discharge port. The opening and closing door 17 is outwardly open, and preferably the opening and closing door 17 is hinged to one side of the outer cylinder 1, and one side is fixed by a latch. The inner cylinder 2 is arranged on the inner side of the outer cylinder 1, and a filter stirring assembly 3 is arranged between the inner cylinder 2 and the outer cylinder 1. The filter stirring assembly 3 is fixed to the outer side of the inner cylinder 2. A fixed sleeve 4 is provided on the inner side of the inner cylinder 2, and the bottom of the fixed sleeve 4 is fixedly connected to the bottom of the outer cylinder 1. A stirring paddle 5 is sleeved on the outer side of the fixed sleeve 4. The cylinder 4 is fixedly provided with a lifting mechanism 10, the telescopic end of the lifting mechanism 10 is rotatably connected to the top of the inner cylinder 2, the top of the telescopic end of the lifting mechanism 10 is fixedly connected with a connecting sleeve 11, the outer side of the connecting sleeve 11 is covered with a rotating cover 12, the rotating cover 12 is rotatably connected to the connecting sleeve 11, and the edge of the rotating cover 12 is fixedly connected to the inner cylinder 2; it also includes a first drive assembly 6 and a second drive assembly 7, the second drive assembly 7 is arranged at the top position of the outer side of the fixed sleeve 4, and is used to provide power for the rotation of the stirring paddle 5; the first drive assembly 6 is arranged at a side position of the telescopic end of the lifting mechanism 10, and is used to provide power for the rotation of the inner cylinder 2. The fixed sleeve 4 is preferably fixed to the lifting mechanism by screws or bolts. While fixing the lifting mechanism, the fixed sleeve 4 also has a wire arrangement groove inside, and the wire arrangement groove is connected to the bottom of the fixed sleeve 4. The wires of the lifting mechanism, the driving motor 1 and the driving motor 2 are all connected to the outside through the wire arrangement groove.

[0052] The filter assembly 3 includes two support rods 8, both of which are fixed on the outside of the inner tube 2. The two support rods 8 are arranged one above and one below, and the angle between the two support rods 8 is ninety degrees. A filter screen 9 is fixedly connected between the two support rods 8.

[0053] The second drive assembly 7 includes a drive motor 15, which is fixedly connected to the top of the outer side of the fixed sleeve 4, and an outer gear ring 16 is fixedly connected to the outer side of the top of the stirring paddle 5. The output end of the drive motor 15 is fixedly connected to drive teeth, and the drive motor 15 is meshed with the outer gear ring 16 through the drive teeth at the output end. The first drive assembly 6 includes a drive motor 13, which is fixedly connected to the telescopic end of the lifting mechanism 10 through a fixed frame, and an inner gear ring 14 is fixedly connected to the bottom of the rotating cover 12. The output end of the drive motor 13 is fixedly connected to drive teeth, and the drive teeth at the output end of the drive motor 13 are meshed with the inner side of the inner gear ring 14. It should be emphasized that the above-mentioned fixed connection structures are all conventional ordinary connections such as conventional screws, bolts or welding unless otherwise emphasized.

[0054] More specifically, step 1 is to stir and add tin chloride between the outer cylinder 1 and the inner cylinder 2, and the inner cylinder 2 is driven to rotate by the first driving component 6, so as to stir the liquid between the inner cylinder 2 and the outer cylinder 1, and at the same time, the ZnSn(OH) generated by hydrolysis is stirred by the filter stirring component 3. 6 The primary particles are stirred and screened, and the agglomerated particles will stay on the screen. Next, the lifting mechanism 10 is started to push the rotating cover 12 to drive the inner cylinder 2 to move upward to achieve the separation of the primary particles and the solution. Next, in step 2, sodium hydroxide particles are added to the inner cylinder 1 to minimize the attachment of secondary particles to the primary particles. Next, by applying downward ultrasound to the top of the filter stirring component 3, the agglomerated particles are vibrated away from the screen to achieve the introduction of the primary particles in step 2. Next, the stirring paddle 5 is driven to rotate by the second drive component 7, so that the liquid is stirred twice by the stirring paddle 5. The frequency of ultrasound is 35-40kHz, the ultrasound time is not less than 10min, and the stirring parameters in all steps are stirring at a speed of 700-1200rpm for 0.5-1h, and the mesh number of the filter 9 is 7000 mesh.

[0055] Example 1

[0056] A ZnSnO 3 Surface growth 2 O 3 The preparation method of the low-temperature gas-sensitive material of the layer is as follows: Step 1, under room temperature, zinc oxalate is dissolved in deionized water and stirred to a concentration of 2.625 g / 100 mL, tin chloride is added during the stirring process, and the molar ratio of zinc oxalate to tin chloride is 1: (1-1.1), and ZnSn (OH) is precipitated. 6 The primary particles were stirred and sieved to obtain solution A1;

[0057] Step 2: Add sodium hydroxide particles with a particle size of 16-20 mesh to the solution A1 obtained in step 1, and the molar ratio of zinc oxalate to sodium hydroxide is 1:9. Let it stand for 10 minutes to precipitate ZnSn(OH) 6 Secondary particles, introduction of ZnSn(OH) 6 The primary particles were then stirred for 10 minutes to obtain ZnSn(OH) 6 Suspension of precursor particles B1.

[0058] Step 3: dissolve indium nitrate in deionized water to obtain an indium nitrate aqueous solution with a concentration of 0.1203 g / 100 mL, and the molar ratio of zinc oxalate to indium nitrate is 1:0.02. At room temperature, slowly drip the indium nitrate aqueous solution into the suspension B1 obtained in step 2 at a rate of 0.08 mL / s, and continuously stir at a speed of 700 rpm for 0.5 h to obtain a white suspension C1, and transfer the white suspension C1 to a reactor with a filling ratio of 0.35:1, and perform hydrothermal reaction at a temperature of 80°C and a pressure of 35 MPa for 8 h, and naturally cool to room temperature to obtain a milky white suspension D1.

[0059] Step 4: Transfer the milky white suspension D1 obtained in step 3 to a centrifuge for centrifugation at 3000 rpm. Wash the white solid obtained by centrifugation with deionized water and ethanol alternately for 3-5 times, and then place it in a 60°C oven and dry it in an air atmosphere for 10 hours. Place the dried powder in a muffle furnace and calcine it in an air atmosphere for 100 minutes at a heating rate of 2°C / min and a calcination temperature of 400°C. Finally, ZnSnO 3 Surface growth 2 O 3 Layer of low-temperature gas-sensitive material.

[0060] Example 2

[0061] Step 1: Dissolve zinc oxalate in deionized water at room temperature and stir to a concentration of 2.855 g / 100 mL. Add tin chloride during stirring. The molar ratio of zinc oxalate to tin chloride is 1:(1-1.1). Precipitate ZnSn(OH) 6 The primary particles were stirred and sieved to obtain solution A2;

[0062] Step 2: Add sodium hydroxide particles with a particle size of 16-20 mesh to the solution A2 obtained in step 1, and the molar ratio of zinc oxalate to sodium hydroxide is 1:10. Let it stand for 12 minutes to precipitate ZnSn(OH) 6 Secondary particles, introduction of ZnSn(OH) 6 The primary particles were then stirred for 13 minutes to obtain ZnSn(OH) 6 Suspension B2 of precursor particles.

[0063] Step 3: dissolve indium nitrate in deionized water to obtain an indium nitrate aqueous solution with a concentration of 0.381 g / 100 mL, and the molar ratio of zinc oxalate to indium nitrate is 1:0.05. At room temperature, the indium nitrate aqueous solution is slowly dripped into the suspension B2 obtained in step 2 at a rate of 0.12 mL / s, and stirred at a speed of 800 rpm for 40 min to obtain a white suspension C2, and the white suspension C2 is transferred to a reactor with a filling ratio of 0.36:1, and hydrothermally reacted at a temperature of 90°C and a pressure of 37 MPa for 9 hours, and naturally cooled to room temperature to obtain a milky white suspension D2.

[0064] Step 4: Transfer the milky white suspension D2 obtained in step 3 to a centrifuge for centrifugation at 3500rpm, wash the white solid obtained by centrifugation with deionized water and ethanol alternately for 3-5 times, and then place it in a 62°C oven and dry it in an air atmosphere for 12 hours. Place the dried powder in a muffle furnace and calcine it in an air atmosphere for 110 minutes at a heating rate of 3°C / min and a calcination temperature of 450°C. Finally, ZnSnO 3 Surface growth 2 O 3 Layer of low-temperature gas-sensitive material.

[0065] Example 3

[0066] Step 1: Dissolve zinc oxalate in deionized water at room temperature and stir to a concentration of 3.085 g / 100 mL. Add tin chloride during stirring. The molar ratio of zinc oxalate to tin chloride is 1:(1-1.1). Precipitate ZnSn(OH) 6 The primary particles were stirred and sieved to obtain solution A3;

[0067] Step 2: Add sodium hydroxide particles with a particle size of 16-20 mesh to the solution A3 obtained in step 1, and the molar ratio of zinc oxalate to sodium hydroxide is 1:11. Let it stand for 14 minutes to precipitate ZnSn(OH) 6 Secondary particles, introduction of ZnSn(OH) 6 The primary particles were then stirred for 17 minutes to obtain ZnSn(OH) 6 Suspension of precursor particles B3.

[0068] Step 3: dissolve indium nitrate in deionized water to obtain an indium nitrate aqueous solution with a concentration of 0.6417 g / 100 mL, and the molar ratio of zinc oxalate to indium nitrate is 1:0.1. At room temperature, the indium nitrate aqueous solution is slowly dripped into the suspension B3 obtained in step 2 at a rate of 0.16 mL / s, and stirred at a speed of 900 rpm for 50 min to obtain a white suspension C3, and the white suspension C3 is transferred to a reactor with a filling ratio of 0.37:1, and hydrothermally reacted at a temperature of 100° C. and a pressure of 39 MPa for 10 h, and naturally cooled to room temperature to obtain a milky white suspension D3.

[0069] Step 4: Transfer the milky white suspension D3 obtained in step 3 to a centrifuge for centrifugation at 4000 rpm. Wash the white solid obtained by centrifugation with deionized water and ethanol alternately for 3-5 times, and then place it in a 64°C oven and dry it in an air atmosphere for 16 hours. Place the dried powder in a muffle furnace and calcine it in an air atmosphere for 120 minutes at a heating rate of 4°C / min and a calcination temperature of 500°C. Finally, ZnSnO 3 Surface growth 2 O 3 Layer of low-temperature gas-sensitive material.

[0070] Example 4

[0071] Step 1: Dissolve zinc oxalate in deionized water at room temperature and stir to a concentration of 3.085 g / 100 mL. Add tin chloride during stirring. The molar ratio of zinc oxalate to tin chloride is 1:(1-1.1). Precipitate ZnSn(OH) 6 The primary particles were stirred and sieved to obtain solution A4;

[0072] Step 2: Add sodium hydroxide particles with a particle size of 16-20 mesh to the solution A obtained in step 1, and the molar ratio of zinc oxalate to sodium hydroxide is 1:12. Let it stand for 20 minutes to precipitate ZnSn(OH) 6 Secondary particles, introduction of ZnSn(OH) 6 The primary particles were then stirred for 20 minutes to obtain ZnSn(OH) 6 Suspension of precursor particles B4.

[0073] Step 3: dissolve indium nitrate in deionized water to obtain an indium nitrate aqueous solution with a concentration of 0.9024 g / 100 mL, and the molar ratio of zinc oxalate to indium nitrate is 1:0.15. At room temperature, slowly drip the indium nitrate aqueous solution into the suspension B4 obtained in step 2 at a rate of 0.2 mL / s, and continuously stir at a speed of 1200 rpm for 1 hour to obtain a white suspension C4, and transfer the white suspension C4 to a reactor with a filling ratio of 0.38:1, and perform hydrothermal reaction at a temperature of 120°C and a pressure of 40 MPa for 12 hours, and naturally cool to room temperature to obtain a milky white suspension D4.

[0074] Step 4: Transfer the milky white suspension D4 obtained in step 3 to a centrifuge for centrifugation at 4500rpm, wash the white solid obtained by centrifugation with deionized water and ethanol alternately for 3-5 times, and then place it in a 75°C oven and dry it in an air atmosphere for 18 hours. Place the dried powder in a muffle furnace and calcine it in an air atmosphere for 140 minutes at a heating rate of 5°C / min and a calcination temperature of 550°C. Finally, ZnSnO 3 Surface growth 2 O 3 Layer of low-temperature gas-sensitive material.

[0075] Performance Test:

[0076] To detect the ZnSnO prepared by the method of the present invention 3 Surface growth 2 O 3 The performance of the low-temperature gas-sensitive material of the layer was firstly 3 Surface growth 2 O 3 After grinding the low-temperature gas-sensitive material in a mortar for 30 minutes, a mixed solution of ethanol and deionized water was dripped into it and ground into a slurry slightly thinner than honey. The slurry was applied to the surface of the alumina ceramic tube with a small brush, and then welded to the base. The WS-60A gas-sensitive element tester was placed under different temperatures to test the sensitivity of 100ppm ethylene glycol and 100ppm triethylamine.

[0077] The test results for ethylene glycol are as follows: Figure 4 As shown, the horizontal axis is the operating temperature and the vertical axis is the sensitivity. At the operating temperature of 100°C, the sensitivity reaches 3817.

[0078] The test results for triethylamine are as follows Figure 5 As shown, the horizontal axis is the operating temperature and the vertical axis is the sensitivity. At the operating temperature of 180°C, the sensitivity reaches 2176.

[0079] Figure 1 The ZnSnO prepared in Example 3 3Surface growth 2 O 3 The XRD pattern of the low-temperature gas-sensitive material of the layer. It can be seen from the figure that the sample ZnSnO 3 / In 2 O 3 There are two main diffraction peaks with higher peaks at 2θ=33.849° and 60.731°, indicating that ZnSnO 3 The main phase has good crystallinity. 3 For example, its (110) and (100) have higher surface energy. Figure 1 We can observe the diffraction peak corresponding to the (110) crystal plane with high intensity, which indicates that the Archimedean ZnSnO 3 The preparation of is conducive to the exposure of the highly active crystal plane (110). In was observed at 2θ = 30.565°, 2θ = 35.466° and 2θ = 51.029° 2 O 3 The diffraction peak of the second phase In 2 O 3 The presence of 3 / In 2 O 3 Composite materials. According to existing research, due to the preparation of ZnSnO 3 During the process, calcination and dehydration will occur, destroying the original hydrogen-oxygen bonds and changing the ZnSnO 3 The internal lattice is arranged to form amorphous ZnSnO 3 , which appears as a weak and broad mantou peak in the XRD spectrum. 3 / In 2 O 3 The diffraction peak intensities of the composite material at 2θ=33.849° and 60.731° are relatively high, indicating that ZnSnO 3 / In 2 O 3 The crystallization degree of the composite material is good, and ZnSnO is successfully prepared. 3 / In 2 O 3 Heterogeneous structure is beneficial to improve ZnSnO 3 / In 2 O 3 Composite material sensitivity.

[0080] Figure 2 ZnSnO 3 Surface growth 2 O 3 Microscopic morphology of low-temperature gas-sensitive materials, ZnSnO 3Archimedean particles have a particle size range of 500-900nm. In the multidimensional surface of the Archimedean body, each triangular face is surrounded by three quadrilateral faces, each quadrilateral face shares a side with the triangular face, and the length of each side ranges from 300-700nm. In particles with a particle size range of 5-50nm 2 O 3 Particles grown on ZnSnO 3 On the multidimensional surface of Archimedean particles, a uniform distribution of In 2 O 3 Particle composite layer. With the increase of indium source In 2 O 3 The thickness of the particle composite layer also increases, but the Archimedean morphology is still maintained when the amount of indium source increases to the range of Example 3. 3 ZnSnO on the highly active surface exposed by the multidimensional substrate 3 WithIn 2 O 3 To form a nn heterojunction, electrons will move from In to 2 O 3 Flow to ZnSnO 3 , thereby increasing the depletion layer thickness, resulting in ZnSnO 3 / In 2 O 3 The resistance of the composite material in air increases, thereby improving gas sensitivity.

[0081] Figure 3 ZnSnO 3 Surface growth 2 O 3 The BJH adsorption and pore size distribution curves of the low-temperature gas-sensitive material of the layer. From the figure, it can be judged that the BJH adsorption curve of the composite material formed belongs to the type IV isotherm, which indicates that the interaction between the adsorbent and the adsorbate is quite weak. The higher the relative pressure, the greater the adsorption amount, showing pore filling. The pore size distribution diagram shows that the composite material contains micropores of 0.8-1.8nm and mesopores of 2.2-40nm. The developed pore structure is conducive to more gas molecules reaching ZnSnO 3 andIn 2 O 3 The composite interface accelerates the gas diffusion rate, thereby improving the gas sensing performance.

[0082] Figure 4 ZnSnO 3 Surface growth 2 O 3 The gas sensing performance diagram of the low-temperature gas-sensitive material of the layer to ethylene glycol is the Archimedean body ZnSnO 3 Surface growth 2 O3 The sensitivity curve of the layered low-temperature gas-sensitive composite material to 100ppm ethylene glycol varies with temperature. The detection working temperature can be reduced to 80-100℃, and its sensitivity can reach 3817 at a concentration of 100ppm ethylene glycol.

[0083] Figure 5 ZnSnO 3 Surface growth 2 O 3 The gas sensing performance diagram of the low-temperature gas-sensitive material of the layer to triethylamine is the Archimedean body ZnSnO 3 Surface growth 2 O 3 The sensitivity curve of the low-temperature gas-sensitive composite material to 100ppm triethylamine varies with temperature. The optimal working temperature of triethylamine gas is 180℃, and its response value to 100ppm triethylamine gas is 2176. Figure 5 Description Archimedean ZnSnO 3 Surface growth 2 O 3 The layered low-temperature gas-sensitive composite material can selectively dual-detect ethylene glycol and triethylamine gases by adjusting the working temperature.

[0084] Figure 6 The ZnSnO prepared in Example 4 3 Surface growth 2 O 3 Microscopic morphology of low-temperature gas-sensitive materials with spheroidized outer shell layer, ZnSnO 3 / In 2 O 3 The diameter of the composite spheroidized particles is about 0.7-1.5 μm. The appearance of the spheroidal morphology is due to the excessive addition of indium source. 2 O 3 When the thickness of the particle composite layer reaches 400nm, the energy of the newly nucleated particles on the surface is higher than that of the grains in the composite layer. 2 O 3 Nanoparticles tend to break away from the surface of Archimedean particles and dissolve into the solvent. As the supersaturation of the solvent increases, In 2 O 3 The particles will be along the ZnSnO 3 The surface of the particles is condensed and stacked layer by layer and filled with ZnSnO 3 Multi-dimensional surface corners make ZnSnO 3 / In 2 O 3 Composite powder shell pelletization.

[0085] Obviously, the above-mentioned embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not limitations on the embodiments of the present invention. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made on the basis of the above description. It is impossible to list all the embodiments here. All obvious changes or modifications derived from the technical solution of the present invention are still within the protection scope of the present invention.

Claims

1. A low-temperature gas-sensitive material with an In2O3 layer grown on the surface of ZnSnO3, characterized in that: ZnSnO3 is an Archimedean particle with a particle size range of 500-900nm. In the multidimensional surface of the Archimedean body, each triangular face is surrounded by three quadrilateral faces, each quadrilateral face shares edges with the triangular face, and the length of each edge ranges from 300-700nm. In2O3 particles with a particle size range of 5-50nm grow on the multidimensional surface of the ZnSnO3 Archimedean particles to form a uniformly distributed In2O3 particle composite layer.

2. The low-temperature gas-sensitive material with an In2O3 layer grown on the surface of ZnSnO3 according to claim 1, characterized in that: The powder particle size of the low-temperature gas-sensitive material with In2O3 layer grown on the surface of ZnSnO3 is 0.7-1.5μm, and the In2O3 nanoparticle layer grows layer by layer along the multi-dimensional surface. The thickness of the In2O3 nanoparticle layer ranges from 200-600nm, forming a ZnSnO3 / In2O3 composite structure with the nanoparticle layer covering the multi-dimensional surface; when the thickness of the In2O3 nanoparticle layer is greater than or equal to 200nm and less than 400nm, the In2O3 particles grow along the multi-dimensional surface of the ZnSnO3 Archimedean body and maintain the Archimedean body morphology. When the thickness of the In2O3 nanoparticle layer is greater than or equal to 400nm and less than or equal to 600nm, a ZnSnO3 / In2O3 low-temperature gas-sensitive composite material with the ZnSnO3 substrate being an Archimedean body and the In2O3 outer shell being spheroidized is formed; the specific surface area of ​​the ZnSnO3 / In2O3 composite material is 42-65m 2 / g, containing micropores of 0.8-1.8nm and mesopores of 2.2-40nm.

3. A method for preparing a low-temperature gas-sensitive material having an In2O3 layer grown on the surface of ZnSnO3 as claimed in claim 1 or 2, characterized in that: The steps are as follows: Step 1: Dissolve zinc oxalate in deionized water at room temperature and stir to a concentration of 2.625-3.325 g / 100 mL. Add tin chloride during stirring. The molar ratio of zinc oxalate to tin chloride is 1:(1-1.1). Precipitate ZnSn(OH)6 primary particles. Stir and sieve to obtain solution A. Step 2: Add sodium hydroxide particles with a particle size of 16-20 mesh to the solution A obtained in step 1, the molar ratio of zinc oxalate to sodium hydroxide is 1: (9-12), let it stand for 10-20 minutes, precipitate ZnSn (OH) 6 secondary particles, introduce ZnSn (OH) 6 primary particles, and then continue stirring for 10-20 minutes to obtain a suspension B containing Archimedean-shaped ZnSn (OH) 6 precursor particles; Step 3, dissolving indium nitrate in deionized water to obtain an indium nitrate aqueous solution with a concentration of 0.1203-0.9024 g / 100 mL, the molar ratio of zinc oxalate to indium nitrate is 1:(0.02-0.15), and slowly dripping the indium nitrate aqueous solution into the suspension B obtained in step 2 at a rate of 0.08-0.2 mL / s at room temperature, stirring continuously at a speed of 700-1200 rpm for 0.5-1 h to obtain a white suspension C, and transferring the white suspension C to a reactor with a filling ratio of (1.75-1.9):5, hydrothermally reacting at a temperature of 80-120° C. and a pressure of 35-40 MPa for 8-12 h, and naturally cooling to room temperature to obtain a milky white suspension D; Step 4. Transfer the milky white suspension D obtained in step 3 to a centrifuge for centrifugation at 3000-4500rpm. Wash the white solid obtained by centrifugation with deionized water and ethanol alternately for 3-5 times, then place it in an oven at 60-75°C, dry it in an air atmosphere for 10-18h, place the dried powder in a muffle furnace, calcine it in an air atmosphere for 100-140min, start heating from room temperature, the heating rate is 2-5°C / min, the calcination temperature is 400-550°C, and finally obtain a low-temperature gas-sensitive material with an In2O3 layer grown on the surface of ZnSnO3.

4. The method for preparing a low-temperature gas-sensitive material having an In2O3 layer grown on the surface of ZnSnO3 according to claim 3, characterized in that: The steps 1 and 2 are completed in a double-layer stirring device, which comprises an outer cylinder (1) and an inner cylinder (2), wherein the inner cylinder (2) is arranged on the inner side of the outer cylinder (1), a filter stirring assembly (3) is arranged between the inner cylinder (2) and the outer cylinder (1), the filter stirring assembly (3) is fixed on the outer side of the inner cylinder (2), a fixed sleeve (4) is arranged on the inner side of the inner cylinder (2), the bottom of the fixed sleeve (4) is fixedly connected to the bottom of the outer cylinder (1), a stirring paddle (5) is sleeved on the outer side of the fixed sleeve (4), a lifting mechanism (10) is fixedly arranged inside the fixed sleeve (4), the telescopic end of the lifting mechanism (10) is rotatably connected to the top of the inner cylinder (2), the top of the telescopic end of the lifting mechanism (10) is fixedly connected to a connecting sleeve (11), a rotating cover (12) is sleeved on the outer side of the connecting sleeve (11), the rotating cover (12) is rotatably connected to the connecting sleeve (11), and the edge of the rotating cover (12) is fixedly connected to the inner cylinder (2); It also includes a first drive assembly (6) and a second drive assembly (7), wherein the second drive assembly (7) is arranged at the top of the outer side of the fixed sleeve (4) and is used to provide power for the rotation of the stirring paddle (5); and the first drive assembly (6) is arranged at a side position of the telescopic end of the lifting mechanism (10) and is used to provide power for the rotation of the inner cylinder (2).

5. The method for preparing a low-temperature gas-sensitive material having an In2O3 layer grown on the surface of ZnSnO3 according to claim 4, characterized in that: The filter screen stirring assembly (3) comprises two support rods (8), both of which are fixed on the outside of the inner cylinder (2), the two support rods (8) are arranged one above the other, the angle between the two support rods (8) is ninety degrees, and a filter screen (9) is fixedly connected between the two support rods (8).

6. The method for preparing a low-temperature gas-sensitive material having an In2O3 layer grown on the surface of ZnSnO3 according to claim 4, characterized in that: The second driving assembly (7) comprises a second driving motor (15), the second driving motor (15) being fixedly connected to the outer top of the fixed sleeve (4), an outer gear ring (16) being fixedly connected to the outer top of the stirring paddle (5), a driving tooth being fixedly connected to the output end of the second driving motor (15), and the second driving motor (15) being meshedly connected to the outer gear ring (16) via the driving tooth at the output end.

7. The method for preparing a low-temperature gas-sensitive material having an In2O3 layer grown on the surface of ZnSnO3 according to claim 4, characterized in that: The first driving assembly (6) comprises a driving motor (13), the driving motor (13) being fixedly connected to the telescopic end of the lifting mechanism (10) via a fixing frame, the bottom of the rotating cover (12) being fixedly connected to an inner gear ring (14), the output end of the driving motor (13) being fixedly connected to driving teeth, and the driving teeth at the output end of the driving motor (13) being meshedly connected to the inner side of the inner gear ring (14).

8. The method for preparing a low-temperature gas-sensitive material having an In2O3 layer grown on the surface of ZnSnO3 according to claim 4, characterized in that: A discharge port is provided on one side of the outer cylinder (1), and an opening and closing door (17) is provided at the discharge port.

9. The method for preparing a low-temperature gas-sensitive material having an In2O3 layer grown on the surface of ZnSnO3 according to claim 4, characterized in that: The first step is to stir and add tin chloride between the outer cylinder (1) and the inner cylinder (2), and drive the inner cylinder (2) to rotate by the first driving component (6), so as to stir the liquid between the inner cylinder (2) and the outer cylinder (1), and at the same time, stir and screen the ZnSn(OH)6 primary particles generated by hydrolysis by the filter stirring component (3), and the agglomerated particles will stay on the screen. Next, the lifting mechanism (10) is started to push the rotating cover (12) to drive the inner cylinder (2) to move upward to achieve separation of the primary particles and the solution. Next, in the second step, sodium hydroxide particles are added to the inner cylinder (1), and then, by applying downward ultrasound to the top of the filter stirring component (3), the agglomerated particles are vibrated away from the screen to achieve the introduction of the primary particles in the second step. Next, the stirring paddle (5) is driven to rotate by the second driving component (7), so as to perform secondary stirring on the liquid by the stirring paddle (5).

10. The method for preparing a low-temperature gas-sensitive material having an In2O3 layer grown on the surface of ZnSnO3 according to claim 9, characterized in that: The frequency of the ultrasound is 35-40 kHz, the ultrasound time is not less than 10 min, the stirring parameters in all steps are stirring at a speed of 700-1200 rpm for 0.5-1 h, and the mesh size of the filter (9) is 7000 mesh.

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