Preparation method and application of high-response ZSM-5@in2o3 gas-sensitive material resistant to silicon poisoning

Abstract

The application discloses a preparation method and application of a high-response ZSM-5@In2O3 gas-sensitive material resistant to silicon poisoning, and belongs to the technical field of metal oxide semiconductor sensors. The method comprises the following steps: firstly, constructing an indium oxide (In2O3) nanoflower with a multi-level structure through a solvothermal method; then, uniformly loading ZSM-5 molecular sieves on the surface of the nanoflower petals to form a heterostructure by adopting an ultrasonic-assisted liquid-phase self-assembly method; and finally, modifying the material surface by using Ar / O2 mixed plasma. The high sensitivity of In2O3 is combined with the anti-poisoning protection of ZSM-5 molecular sieves, so that the short service life defect of a single metal oxide in a polluted environment is overcome.

Description

Technical Field

[0001] This invention belongs to the field of metal oxide semiconductor sensor technology, and particularly relates to a method for preparing and applying a high-response ZSM-5@In2O3 gas-sensitive material resistant to silicon poisoning. Background Technology

[0002] Indium oxide (In₂O₃), as a typical n-type metal oxide semiconductor, has long been a research hotspot in the field of gas-sensitive materials due to its excellent conductivity and high sensitivity to reducing gases such as ethanol. However, single metal oxide materials are often insufficient to meet the increasingly complex industrial monitoring needs.

[0003] In fields such as communications, medical care, and industrial monitoring, the most severe challenge facing semiconductor gas sensors is the phenomenon of "silicon poisoning." Organosilicon compounds in the environment (such as hexamethyldisiloxane, HMDSO) decompose at the sensor's operating temperature, forming a dense silicon dioxide (SiO2) film on the material surface. This film blocks gas diffusion channels and covers active sites, causing a sharp drop in sensor sensitivity or even complete failure, severely limiting its lifespan.

[0004] Currently, gas-sensing performance is highly dependent on the microstructure and morphology of materials. Although studies have attempted to prepare nanostructures using methods such as sol-gel, problems such as powder agglomeration and poor dispersibility are still prevalent, making it difficult to meet practical requirements. Furthermore, existing preparation processes are often complex and demanding, with high raw material costs, hindering large-scale production. While ZSM-5 molecular sieves can effectively intercept organosilicon molecules using their microporous shape-selective filtration properties, achieving uniform loading of the molecular sieve during heterostructure construction and addressing the resulting kinetic hysteresis issues such as prolonged response / recovery times remain current technical challenges.

[0005] Therefore, how to construct heterogeneous structures through efficient self-assembly processes and optimize active sites by combining advanced surface treatment technologies to obtain novel gas-sensitive materials that combine anti-poisoning ability, high sensitivity, and rapid response recovery performance is a key problem that urgently needs to be solved in this field. Summary of the Invention

[0006] To address the shortcomings of existing semiconductor gas sensors in industrial monitoring due to susceptibility to organosilicon contamination leading to failure, this invention proposes a method for preparing and applying a highly responsive ZSM-5@In2O3 gas-sensitive material resistant to silicon poisoning. This invention employs ultrasound-assisted liquid-phase self-assembly technology to uniformly load ZSM-5 molecular sieves onto the surface of In2O3 nanoflowers, constructing a heterostructure. Further, Ar / O2 plasma treatment is combined to enhance the material's response characteristics. The composite material prepared by this method not only utilizes the shape-selective filtration function of the molecular sieve to provide protection against silicon poisoning but also significantly optimizes the response kinetics through plasma surface treatment. Therefore, this material exhibits high response values, fast response times, and rapid recovery times to gases such as ethanol in complex polluted environments.

[0007] To achieve the above objectives, the present invention provides the following technical solution: A method for preparing a highly responsive ZSM-5@In2O3 gas-sensitive material resistant to silicon poisoning includes the following steps: (1) Indium salt and structure directing agent were dissolved in anhydrous ethanol and reacted by solvothermal method to obtain precursor. After washing, drying and calcination, In2O3 nanopowder with multi-level flower structure was obtained. (2) The In2O3 nanoparticles and ZSM-5 molecular sieves obtained in step (1) are dispersed in anhydrous ethanol and then mixed, magnetically stirred, and calcined twice. Through liquid phase self-assembly, ZSM-5 particles are uniformly anchored on the surface of In2O3 nanoparticles to obtain composite material. (3) The composite material prepared in step (2) is placed in a plasma cleaner and Ar / O2 mixed gas is introduced for plasma treatment. By ion bombardment and active oxygen injection, the oxygen vacancies and active sites on the surface of the material are increased, and a high-response ZSM-5@In2O3 gas-sensitive material is obtained.

[0008] This invention designs a core-shell heterostructured nanoflower composite material, utilizing hierarchical indium oxide (In₂O₃) nanoflowers as a highly active sensitive framework. Through an ultrasound-assisted liquid-phase self-assembly process, ZSM-5 molecular sieves with shape-selective filtration capabilities are uniformly anchored onto the surface of the nanoflower petals, constructing an anti-poisoning barrier and a heterojunction interface. Furthermore, Ar / O₂ mixed plasma treatment technology is introduced, using the synergistic effect of physical bombardment and chemical oxidation to remove residual organic matter from the material surface and induce abundant oxygen vacancies and active sites. This compensates for the gas diffusion resistance that may be introduced by the supported molecular sieve, achieving a comprehensive improvement in gas-sensing performance.

[0009] Further, in step (1), the mass ratio of the indium salt to the structure directing agent is (0.3~1):(1.61~3.22); wherein the indium salt is selected from indium chloride or indium nitrate; and the structure directing agent is urea and sodium hexadecyl sulfate in a mass ratio of (0.36~0.72):(1.25~2.5).

[0010] Furthermore, in step (1), the temperature of the solvothermal reaction is 160°C and the time is 24 hours.

[0011] Furthermore, in step (1), the temperature of the first calcination is 500~600℃ and the time is 2~3 hours.

[0012] Further, in step (2), the mass ratio of the In2O3 nanoparticles to the ZSM-5 molecular sieve is (17~19):(1~3).

[0013] Furthermore, in step (2), the magnetic stirring time is 3 hours; the secondary calcination temperature is 400℃ and the time is 2 hours.

[0014] Further, in step (3), the volume ratio of Ar to O2 in the Ar / O2 mixed gas is (1~3):1.

[0015] Furthermore, in step (3), the power of the plasma treatment is 50~150W, and the treatment time is 5~15 minutes.

[0016] This invention also provides a high-response ZSM-5@In2O3 gas-sensitive material prepared using the above-described method. This material possesses shape-selective filtration capabilities provided by the ZSM-5 micropores to block organosilicon macromolecules, and abundant oxygen vacancies generated by plasma treatment, thereby achieving a high response value and fast response / recovery time. After Ar / O2 plasma treatment, the material's response value to ethanol gas is significantly improved, and the response and recovery times are shortened by 30-50% compared to the untreated state.

[0017] This invention also provides an application of a high-response ZSM-5@In2O3 gas-sensitive material in an anti-silicon poisoning sensor. The sensor comprises a ceramic tube or microelectromechanical system (MEMS) substrate, with the high-response ZSM-5@In2O3 gas-sensitive material coated on the substrate surface, for long-lifetime monitoring of ethanol gas in complex environments containing hexamethyldisiloxane (HMDSO).

[0018] Compared with the prior art, the present invention has the following advantages and technical effects: This invention overcomes the short lifespan of single metal oxides in polluted environments by combining the high sensitivity of In₂O₃ with the anti-poisoning protection of ZSM-5. The microporous effect of the ZSM-5 layer effectively intercepts larger organosilicon molecules, preventing them from decomposing on the sensitive layer surface to form a SiO₂ poisoning layer. The introduction of Ar / O₂ plasma treatment technology solves the problem of slowed response and recovery speeds in composite materials due to protective layer modification. Tests show that the treated material, while maintaining the same anti-poisoning ability, has a 30-50% shorter response and recovery time compared to the untreated material. Ultrasonic-assisted self-assembly replaces complex chemical coating, resulting in a simple, repeatable process using readily available and inexpensive raw materials. Attached Figure Description

[0019] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 X-ray diffraction patterns of In2O3 nanopowder, ZSM-5 molecular sieve, and ZSM-5@In2O3 (after plasma treatment) gas-sensitive material in Example 1; Figure 2 This is a field emission electron microscope (FET) image of the microstructure of the In2O3 nanoparticles prepared in Example 1. Figure 3 This is a field emission electron microscope (FEM) scan of the high-response ZSM-5@In2O3 (after plasma treatment) gas-sensitive material prepared in Example 1. Figure 4 This is a high-resolution transmission electron microscope image of the high-response ZSM-5@In2O3 (after plasma treatment) gas-sensitive material prepared in Example 1; Figure 5 XPS spectra of oxygen vacancy content on the material surface before and after Ar / O2 plasma treatment; Figure 6 The sensor prepared using In2O3 nanoparticles and ZSM-5@In2O3-A (after plasma treatment) gas-sensitive material as raw materials shows the response sensitivity curves of a sensor to different concentrations of ethanol molecules at 350℃. Figure 7 The sensor prepared using ZSM-5@In2O3-B (after plasma treatment) gas-sensitive material prepared in Example 2 as raw material shows the response sensitivity change curve of the sensor to different concentrations of ethanol molecules at 350°C. Figure 8 The sensor prepared using ZSM-5@In2O3-C (after plasma treatment) gas-sensitive material obtained in Example 2 as raw material is shown as the response sensitivity curve of a sensor to different concentrations of ethanol molecules at 350°C. Figure 9 This is a comparison of the response sensitivity of sensors prepared using In2O3 nanoparticles and ZSM-5@In2O3-A (after plasma treatment) gas-sensitive material to ethanol molecules in the presence of interfering gases. Figure 10 This is a comparison of the response sensitivity of a sensor prepared using ZSM-5@In2O3-B (after plasma treatment) gas-sensitive material prepared in Example 2 to ethanol molecules in the presence of interfering gases. Figure 11 This is a comparison of the response sensitivity of ZSM-5@In2O3-C (after plasma treatment) gas-sensitive material prepared in Example 2 to ethanol molecules in the presence of interfering gases. Figure 12 The graph shows the response stability of a sensor prepared from In2O3 nanoparticles and ZSM-5@In2O3 (after plasma treatment) gas-sensitive material after five cycles of poisoning in an environment containing 50 ppm hexamethyldisiloxane. Figure 13 The graph shows the response stability of a sensor prepared using ZSM-5@In2O3-A (after plasma treatment) gas-sensitive material prepared in Example 1 as raw material after five cycles of poisoning in an environment containing 50 ppm hexamethyldisiloxane. Figure 14 The graph shows the response stability of a sensor prepared using ZSM-5@In2O3-B (after plasma treatment) gas-sensitive material prepared in Example 1 as raw material after five cycles of poisoning in an environment containing 50 ppm hexamethyldisiloxane. Figure 15 The graph shows the response stability of a sensor prepared using ZSM-5@In2O3-C (after plasma treatment) gas-sensitive material prepared in Example 1 as raw material after five cycles of poisoning in an environment containing 50 ppm hexamethyldisiloxane. Figure 16 The graph shows the response time and recovery time of a sensor prepared from In2O3 nanoparticles to 50 ppm ethanol. Figure 17 The response time and recovery time curves of a sensor prepared using ZSM-5@In2O3-A (after plasma treatment) gas-sensitive material prepared in Example 1 as raw material to 50 ppm ethanol are shown. Figure 18 The response time and recovery time curves of a sensor prepared using ZSM-5@In2O3-B (after plasma treatment) gas-sensitive material prepared in Example 2 as raw material to 50 ppm ethanol are shown. Figure 19The graph shows the response time and recovery time of a sensor prepared using ZSM-5@In2O3-C (after plasma treatment) gas-sensitive material prepared in Example 3 as the raw material to 50 ppm ethanol. Detailed Implementation

[0020] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0021] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0022] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0023] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0024] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0025] This invention provides a method for preparing a highly responsive ZSM-5@In2O3 gas-sensitive material resistant to silicon poisoning. The method primarily utilizes the microporous shape-selective filtering effect of a ZSM-5 shell constructed through ultrasonic-assisted self-assembly to effectively intercept organosilicon macromolecules (HMDSO), preventing the sensitive material from failing due to "silicon poisoning." Simultaneously, the introduced Ar / O2 plasma significantly increases the concentration of active sites on the material surface through surface bombardment and induced oxygen vacancies, effectively solving the kinetic hysteresis problem caused by the protective layer modification. This significantly shortens the sensor's response and recovery times, resulting in an ethanol gas-sensitive material with long lifespan, high sensitivity, and rapid detection characteristics. The preparation process of this invention is simple and reproducible, and the obtained material can be widely applied in gas detection fields with organosilicon pollution risks, such as communications, medical, and industrial monitoring. Furthermore, the side-heated gas sensor prepared using this material exhibits better and more sensitive sensing performance for ethanol. The specific steps include: (1) Indium salt (In(NO3)3·xH2O) and structure directing agent were dissolved in anhydrous ethanol and subjected to a solvothermal reaction at 160°C for 24 hours. The reaction product was washed, dried and calcined once to obtain In2O3 nanoparticles with a multi-level flower-like structure composed of nanoparticles. The nanoflowers have a large specific surface area, providing sufficient contact sites for subsequent molecular sieve loading. (2) The In2O3 nanoparticles obtained in step (1) and ZSM-5 molecular sieves are dispersed in anhydrous ethanol. The mass transfer enhancement effect generated by magnetic stirring is used to force the molecular sieve particles to overcome the charge repulsion. Through physical adsorption and electrostatic interaction, they grow uniformly and anchor on the petal surface of the In2O3 nanoflower, forming a preliminary ZSM-5@In2O3 heterostructure. The precipitate is washed, centrifuged and dried and then calcined twice. Through liquid phase self-assembly, the ZSM-5 particles are uniformly anchored on the surface of the In2O3 nanoflower petals, so that a stable heterostructure interface is formed between In2O3 and ZSM-5, improving the charge transport efficiency and obtaining the composite material. (3) The composite material prepared in step (2) is uniformly laid in the treatment chamber of a plasma cleaner. After evacuating to the set pressure, an Ar / O2 mixed gas is introduced for plasma treatment. Through ion bombardment and active oxygen injection, the oxygen vacancies and active sites on the material surface are increased to obtain a high-response ZSM-5@In2O3 gas-sensitive material. In this step, the Ar plasma etches the material surface through high-energy bombardment, removes impurities in the micropores, and increases the surface roughness; the O2 plasma induces the generation of a high concentration of adsorbed oxygen components (O2) on the material surface. - O 2- By regulating the oxygen vacancy content, the adsorption and desorption processes of gas molecules can be significantly shortened, thereby optimizing the response speed.

[0026] In step (1) of the following optional embodiments of the present invention, the mass ratio of indium salt to structure directing agent is (0.3~1):(1.61~3.22). For example, in the following preferred embodiments of the present invention, the mass ratio of indium salt to structure directing agent is 0.3:1.61, 0.5:2.53 or 1:3.22. The indium salt is selected from indium chloride or indium nitrate. The structure directing agent is urea and sodium hexadecyl sulfate in a mass ratio of (0.36~0.72):(1.25~2.5). For example, in the following preferred embodiments of the present invention, the mass ratio of urea and sodium hexadecyl sulfate is 0.36:1.25, 0.65:1.88 or 0.72:2.5.

[0027] In step (1) of the following optional embodiments of the present invention, the temperature of the first calcination is 500~600℃ (e.g., 600℃) and the time is 2~3 hours (e.g., 2 hours).

[0028] In step (2) of the following optional embodiments of the present invention, the mass ratio of In2O3 nanoparticles to ZSM-5 molecular sieves is (17~19):(1~3). Exemplarily, in the following preferred embodiments of the present invention, the mass ratio of In2O3 nanoparticles to ZSM-5 molecular sieves is 19:1, 18:2 or 17:3.

[0029] In step (2) of the following optional embodiment of the present invention, the magnetic stirring time is 3 hours; the secondary calcination temperature is 400°C and the time is 2 hours.

[0030] In step (3) of the following optional embodiments of the present invention, the volume ratio of Ar to O2 in the Ar / O2 mixed gas is (1~3):1. Exemplarily, in the following preferred embodiments of the present invention, the volume ratio of Ar to O2 is 1:1, 2:1 or 3:1.

[0031] In step (3) of the following optional embodiments of the present invention, the power of plasma treatment is 50~150W (e.g., 50W, 100W or 150W), and the treatment time is 5~15 minutes (e.g., 5 minutes, 10 minutes or 15 minutes).

[0032] The high-response ZSM-5@In2O3 gas-sensitive material obtained by the above preparation method can be used to prepare anti-silicon poisoning gas-sensitive elements, preferably for ethanol gas detection, especially in environments containing organosilicon compounds (such as hexamethyldisiloxane HMDSO) such as communication base station monitoring, medical environment monitoring and industrial waste gas detection.

[0033] The high-response ZSM-5@In2O3 gas-sensitive material obtained in this invention exhibits a complete three-dimensional In2O3 nanoflower morphology, with a uniform shell layer composed of ZSM-5 molecular sieves covering the surface of the petals. The ZSM-5 molecular sieves have a particle size of approximately 50-100 nm and retain regular microporous channels of about 0.55 nm. This structure forms a typical coaxial multi-level heterogeneous interface, namely, a semiconductor sensitive core with high carrier concentration inside and a semiconductor composite shell with shape-selective filtering function outside.

[0034] Unless otherwise specified, "room temperature" in this invention refers to 25±2℃.

[0035] All raw materials used in this invention were purchased from the market.

[0036] The technical solution of the present invention will be further illustrated by the following embodiments.

[0037] Example 1 A method for preparing a highly responsive ZSM-5@In2O3 gas-sensitive material resistant to silicon poisoning includes the following steps: (1) Weigh 0.3g of In(NO3)3·xH2O and dissolve it in 30mL of anhydrous ethanol. Add 0.36g of urea and 1.25g of sodium hexadecyl sulfate as structure directing agents. Stir continuously with magnetic force at 40℃ for 6 hours. Seal the resulting suspension in a 50mL hydrothermal reactor and solvothermal react at 160℃ for 24 hours. The resulting precipitate is washed with deionized water and ethanol, centrifuged and collected, dried at 60℃ for 24 hours, and finally calcined at 600℃ for 2 hours to obtain In2O3 nanoparticles with a multi-level flower-like structure. (2) Weigh 190 mg of In2O3 nanoparticles obtained in step (1) and disperse them in 20 mL of anhydrous ethanol. Then, stir magnetically for 30 minutes to obtain an In2O3 suspension. Then, put 10 mg of ZSM-5 powder into another beaker containing 10 mL of anhydrous ethanol and sonicate for 30 minutes to obtain a ZSM-5 suspension. Keep the In2O3 suspension under magnetic stirring and slowly drip 10 mg of ZSM-5 suspension into the beaker containing the In2O3 suspension using a dropper. After the addition is complete, seal the mouth of the beaker with plastic wrap and continue stirring at room temperature for 3 hours. The resulting precipitate is washed with deionized water and ethanol, centrifuged and collected, and dried at 60°C overnight. Finally, calcined at 400°C for 2 hours to obtain the composite material. (3) The composite material obtained in step (2) is placed in the plasma treatment chamber and a mixed gas with a volume ratio of Ar to O2 of 2:1 is introduced; the power is set to 100W and the treatment is carried out continuously for 10 minutes to increase the surface active oxygen content and shorten the response recovery time, so as to obtain the high-response ZSM-5@In2O3 gas-sensitive material (denoted as ZSM-5@In2O3-A).

[0038] Example 2 A method for preparing a highly responsive ZSM-5@In2O3 gas-sensitive material resistant to silicon poisoning includes the following steps: (1) Weigh 0.5g of In(NO3)3·xH2O and dissolve it in 40mL of anhydrous ethanol. Add 0.65g of urea and 1.88g of sodium hexadecyl sulfate as structure directing agents. Stir continuously with magnetic force at 40℃ for 6 hours. Seal the resulting suspension in a 50mL hydrothermal reactor and solvothermal react at 160℃ for 24 hours. The resulting precipitate is washed with deionized water and ethanol, centrifuged and collected, dried at 60℃ for 24 hours, and finally calcined at 600℃ for 2 hours to obtain In2O3 nanoparticles with a multi-level flower-like structure. (2) Weigh 180 mg of In2O3 nanoparticles obtained in step (1) and disperse them in 20 mL of anhydrous ethanol. Then, stir magnetically for 30 minutes to obtain an In2O3 suspension. Then, put 20 mg of ZSM-5 powder into another beaker containing 10 mL of anhydrous ethanol and sonicate for 30 minutes to obtain a ZSM-5 suspension. Keep the In2O3 suspension under magnetic stirring and slowly drip 10 mg of ZSM-5 suspension into the beaker containing the In2O3 suspension using a dropper. After the dripping is completed, seal the mouth of the beaker with plastic wrap and continue stirring at room temperature for 3 hours. The precipitate obtained is washed with deionized water and ethanol, centrifuged and collected, and dried at 60°C overnight. Finally, calcined at 400°C for 2 hours to obtain the composite material. (3) The composite material obtained in step (2) is placed in the plasma treatment chamber and a mixed gas with a volume ratio of Ar to O2 of 3:1 is introduced; the power is set to 150W and the treatment is carried out continuously for 5 minutes to increase the surface active oxygen content and shorten the response recovery time, so as to obtain the high-response ZSM-5@In2O3 gas-sensitive material (denoted as ZSM-5@In2O3-B).

[0039] Example 3 A method for preparing a highly responsive ZSM-5@In2O3 gas-sensitive material resistant to silicon poisoning includes the following steps: (1) Weigh 1g of In(NO3)3·xH2O and dissolve it in 80mL of anhydrous ethanol. Add 0.72g of urea and 2.5g of sodium hexadecyl sulfate as structure directing agents. Stir continuously with magnetic force at 40℃ for 6 hours. Seal the resulting suspension in a 100mL hydrothermal reactor and solvothermal react at 160℃ for 24 hours. The resulting precipitate is washed with deionized water and ethanol, centrifuged and collected, dried at 60℃ for 24 hours, and finally calcined at 600℃ for 2 hours to obtain In2O3 nanoparticles with a multi-level flower-like structure. (2) Weigh 170 mg of In2O3 nanoparticles obtained in step (1) and disperse them in 20 mL of anhydrous ethanol. Then, stir magnetically for 30 minutes to obtain an In2O3 suspension. Then, put 30 mg of ZSM-5 powder into another beaker containing 10 mL of anhydrous ethanol and sonicate for 30 minutes to obtain a ZSM-5 suspension. Keep the In2O3 suspension under magnetic stirring and slowly drip 10 mg of ZSM-5 suspension into the beaker containing the In2O3 suspension using a dropper. After the dripping is completed, seal the mouth of the beaker with plastic wrap and continue stirring at room temperature for 3 hours. The resulting precipitate is washed with deionized water and ethanol, centrifuged and collected, and dried at 60°C overnight. Finally, calcined at 400°C for 2 hours to obtain the composite material. (3) Place the composite material obtained in step (2) into the plasma treatment chamber and introduce a mixed gas with a volume ratio of Ar to O2 of 1:1; set the power to 50W and treat continuously for 15min to increase the surface active oxygen content and shorten the response recovery time to obtain a high-response ZSM-5@In2O3 gas-sensitive material (denoted as ZSM-5@In2O3-C).

[0040] Figure 1 The X-ray diffraction patterns of In2O3 nanopowder, ZSM-5 molecular sieve, and ZSM-5@In2O3 gas-sensitive material in Example 1 are shown in the figure. As can be seen from the figure, the ZSM-5@In2O3 composite material has the characteristic diffraction peaks of both In2O3 and ZSM-5, proving that the two were successfully composited without the introduction of other impurity phases.

[0041] Figure 2 The image shows a field emission electron microscope (FESEM) image of the microstructure of the In2O3 nanoparticles prepared in Example 1. As can be seen from the image, the prepared In2O3 nanoparticles exhibit a uniformly dispersed multi-level flower-like structure, with petals assembled from nanoparticles, and have a large specific surface area.

[0042] Figure 3 The image shows a field emission electron microscope (FET) scan of the high-response ZSM-5@In2O3 gas-sensitive material prepared in Example 1. As can be seen from the image, the ZSM-5 molecular sieve is uniformly loaded on the surface of the In2O3 nanopetals, forming a complete core-shell heterostructure.

[0043] Figure 4 The image shows a high-resolution transmission electron microscope (HRTEM) image of the high-response ZSM-5@In2O3 gas-sensitive material prepared in Example 1. As can be seen from the image, the lattice fringes at the ZSM-5@In2O3 heterojunction confirm that a close-contact heterojunction is formed between In2O3 and ZSM-5.

[0044] Figure 5XPS spectra of oxygen vacancy content on the material surface before and after Ar / O2 plasma treatment are compared. As can be seen from the figure, the oxygen vacancy content on the material surface increases significantly after Ar / O2 plasma treatment, indicating that plasma treatment effectively introduces active sites.

[0045] Application Example 1 The ZSM-5@In2O3 gas-sensitive materials obtained in Examples 1-3 and the In2O3 nanopowder prepared in Example 1 were respectively mixed with anhydrous ethanol to form sensitive slurries, and respectively applied to silicon-based sensor chips using electrostatic direct writing technology. The chip area was 1mm×1mm, the sensitive layer thickness was about 0.5mm, and the power consumption was about 13mw (350℃). The silicon-based sensor had four sub-sensing units, each sensor measuring 4.6mm×4.6mm. The front of the sensor was the sensitive material layer, and the back of the sensor was the heating electrode, thus obtaining the silicon-based sensor.

[0046] The sensor was placed in a static testing system with the sensor element operating at 350℃. Ethanol gas molecules of different concentrations (range 10~100ppm) were then introduced. A data acquisition card was used to collect the voltage division values ​​of the sensor's circuitry in air and in different concentrations of ethanol atmospheres with an air background. These values ​​were used as the sensor's signal. The sensor's response sensitivity was calculated using a PC.

[0047] Gas response sensitivity (S) is defined as the resistance R of a component in air. a Resistance value R after the component adsorbs gas g The ratio, i.e., S=R a / R g , where R a =R L (V c -V air ) / V air R g =R L (V c -V gas ) / V gas V air and V gas These represent the partial pressure of the gas-sensitive element in air and the partial pressure of the gas being measured, R. L V is the resistance value of the series voltage divider resistor in the voltage divider circuit. c The total voltage supplied to the voltage divider circuit.

[0048] The formula for calculating sensor response sensitivity using PC is S=V gas (V c -V air ) / V air (V) c -Vgas ).

[0049] Figure 6 The sensor prepared using In2O3 nanoparticles and ZSM-5@In2O3-A gas-sensitive material as raw materials exhibits response sensitivity curves to different concentrations of ethanol molecules at 350℃. The sensitivity curves show that the sensor prepared based on ZSM-5@In2O3 gas-sensitive material shows higher response values ​​than the pure In2O3 sensor to different concentrations of ethanol (10~100ppm) at 350℃.

[0050] Figure 7 The sensor prepared using ZSM-5@In2O3-B gas-sensitive material prepared in Example 2 as raw material exhibits a high response sensitivity curve for different concentrations of ethanol molecules at 350℃. The sensitivity curve shows that the sensor prepared based on ZSM-5@In2O3-B gas-sensitive material shows a high response value for different concentrations of ethanol (10-100ppm) at 350℃, and the response sensitivity increases monotonically with increasing ethanol concentration. Its overall response performance is better than that of the pure In2O3 sensor.

[0051] Figure 8 The sensitivity curves of the sensor prepared using the ZSM-5@In2O3-C gas-sensitive material obtained in Example 2 as raw material are shown to indicate the change in response sensitivity to different concentrations of ethanol molecules at 350°C. The sensitivity curves show that the sensor prepared based on the ZSM-5@In2O3-C gas-sensitive material also exhibits good concentration-dependent response to different concentrations of ethanol (10-100 ppm) at 350°C, with response values ​​higher than those of the pure In2O3 sensor, verifying the excellent sensitivity characteristics of this composite material to ethanol.

[0052] Application Example 2 The ZSM-5@In2O3 gas-sensitive materials obtained in Examples 1-3 and the In2O3 nanopowder prepared in Example 1 were respectively mixed with anhydrous ethanol to form sensitive slurries. The slurries were then applied to a silicon-based sensor chip using electrostatic direct writing technology. The chip area was 1 mm × 1 mm, the thickness of the sensitive layer was approximately 0.5 mm, and the power consumption was approximately 13 mW (350 °C). The silicon-based sensor had four sub-sensing units, each with a sensor size of 4.6 mm × 4.6 mm. The front of the sensor was the sensitive material layer, and the back of the sensor was the heating electrode, thus obtaining the silicon-based sensor.

[0053] The sensor was placed in a static testing system with the sensor element operating at 350℃. Ethanol gas molecules at concentrations ranging from 10 to 100 ppm (10, 20, 30, 50, 70, 100 ppm) were used, along with 50 ppm of methanol, formaldehyde, acetone, ammonia, and nitrogen dioxide (a single gas) as interfering gases, to further investigate the sensor's response sensitivity. The voltage division values ​​of the circuit system were collected via a data acquisition card in air and in ethanol atmospheres with different concentrations against an air background, and these changes were used as the sensor's signal. The sensor's response sensitivity was calculated using a PC.

[0054] Figure 9 This is a comparison chart showing the response sensitivity of sensors prepared using In2O3 nanoparticles and ZSM-5@In2O3-A gas-sensitive material to ethanol molecules in the presence of interfering gases. The selectivity comparison chart shows that the ZSM-5@In2O3 sensor maintains the highest response sensitivity to ethanol in the presence of interfering gases such as methanol, formaldehyde, acetone, ammonia, and nitrogen dioxide, demonstrating good selectivity.

[0055] Figure 10 This is a comparison chart showing the response sensitivity of a sensor prepared using the ZSM-5@In2O3-B gas-sensitive material obtained in Example 2 to ethanol molecules in the presence of interfering gases. The selectivity comparison chart shows that the ZSM-5@In2O3-B sensor still maintains the highest response sensitivity to ethanol in the presence of interfering gases such as methanol, formaldehyde, acetone, ammonia, and nitrogen dioxide, indicating that it has good gas selectivity and is suitable for ethanol detection in complex atmospheres.

[0056] Figure 11 The image shows a comparison of the response sensitivity of the ZSM-5@In2O3-C gas-sensitive material prepared in Example 2 to ethanol molecules in the presence of interfering gases. The selectivity comparison image shows that the ZSM-5@In2O3-C sensor also exhibits a significantly higher response value to ethanol than to other interfering gases, indicating that the composite material maintains excellent selective recognition ability under the combined effect of plasma treatment and ZSM-5 loading.

[0057] Application Example 3 The ZSM-5@In2O3 gas-sensitive materials obtained in Examples 1-3 and the In2O3 nanopowder prepared in Example 1 were respectively mixed with anhydrous ethanol to form sensitive slurries. The slurries were then applied to a silicon-based sensor chip using electrostatic direct writing technology. The chip area was 1 mm × 1 mm, the thickness of the sensitive layer was approximately 0.5 mm, and the power consumption was approximately 13 mW (350 °C). The silicon-based sensor had four sub-sensing units, each with a sensor size of 4.6 mm × 4.6 mm. The front of the sensor was the sensitive material layer, and the back of the sensor was the heating electrode, thus obtaining the silicon-based sensor.

[0058] The prepared sensor was placed in an environment containing 50 ppm hexamethyldisiloxane (HMDSO) for five cycles of poisoning testing. The sensor's response to the target gas (e.g., ethanol) was recorded after each cycle. The silicon poisoning resistance of the composite material was evaluated by comparing the response decay of the pure In₂O₃ sensor and the ZSM-5@In₂O₃ sensor. Five cycles of poisoning were conducted in an environment containing 50 ppm hexamethyldisiloxane (HMDSO).

[0059] Figure 12 The figure shows a comparison of the response stability of sensors prepared using In2O3 nanoparticles and ZSM-5@In2O3 gas-sensitive materials after five cycles of poisoning in an environment containing 50 ppm hexamethyldisiloxane. As can be seen from the figure, the response value of the pure In2O3 sensor decays rapidly in an environment containing 50 ppm hexamethyldisiloxane.

[0060] Figure 13 The graph shows the response stability of a sensor prepared using ZSM-5@In2O3-A gas-sensitive material obtained in Example 1 after five cycles of poisoning in an environment containing 50 ppm hexamethyldisiloxane. As can be seen from the graph, the response value of the ZSM-5@In2O3 sensor remains stable after five cycles, demonstrating excellent resistance to silicon poisoning.

[0061] Figure 14 The figure shows a comparison of the response stability of the sensor prepared using ZSM-5@In2O3-B gas-sensitive material obtained in Example 1 after five cycles of poisoning in an environment containing 50 ppm hexamethyldisiloxane. As can be seen from the figure, after five cycles of poisoning in an environment containing 50 ppm hexamethyldisiloxane (HMDSO), the response value of the ZSM-5@In2O3-B sensor remained basically stable with minimal attenuation, demonstrating good resistance to silicon poisoning.

[0062] Figure 15The figure shows a comparison of the response stability of a sensor prepared using ZSM-5@In2O3-C gas-sensitive material obtained in Example 1 after five cycles of poisoning in an environment containing 50 ppm hexamethyldisiloxane. As can be seen from the figure, the response value of the ZSM-5@In2O3-C sensor remained stable in the same five-cycle poisoning test without significant decrease, further confirming the effective interception effect of the ZSM-5 molecular sieve shell on organosilicon macromolecules.

[0063] Application Example 4 The ZSM-5@In2O3 gas-sensitive materials obtained in Examples 1-3 and the In2O3 nanopowder prepared in Example 1 were respectively mixed with anhydrous ethanol to form sensitive slurries. The slurries were then applied to a silicon-based sensor chip using electrostatic direct writing technology. The chip area was 1 mm × 1 mm, the thickness of the sensitive layer was approximately 0.5 mm, and the power consumption was approximately 13 mW (350 °C). The silicon-based sensor had four sub-sensing units, each with a sensor size of 4.6 mm × 4.6 mm. The front of the sensor was the sensitive material layer, and the back of the sensor was the heating electrode, thus obtaining the silicon-based sensor.

[0064] The prepared sensor was placed in a static testing system with the operating temperature set to 350℃, and ethanol gas at a concentration of 50 ppm was introduced. The sensor's response time to 50 ppm ethanol (the time required for the resistance change to reach a stable value from contact with the gas) and recovery time (the time required for the resistance to return to the air value from removal from the gas) were recorded. The time differences between the ZSM-5@In2O3 sensor treated with Ar / O2 plasma and the untreated sensor were compared.

[0065] Figure 16 The graph shows the response time and recovery time of the sensor prepared using In2O3 nanoparticles as raw material to 50 ppm ethanol. As can be seen from the graph, the sensor prepared using pure In2O3 nanoparticles as raw material has a relatively long response time and recovery time to 50 ppm ethanol, indicating that its kinetic performance needs to be improved. This provides a benchmark for performance improvement after subsequent plasma treatment.

[0066] Figure 17 The graph shows the response time and recovery time of the sensor prepared using ZSM-5@In2O3-A (after plasma treatment) gas-sensitive material prepared in Example 1 as raw material to 50 ppm ethanol. As can be seen from the graph, the response time and recovery time of the ZSM-5@In2O3 sensor after Ar / O2 plasma treatment to 50 ppm ethanol are shortened by 30-50% compared with the untreated sensor, which effectively improves the kinetic performance.

[0067] Figure 18The graph shows the response time and recovery time of a sensor prepared using ZSM-5@In2O3-B (after plasma treatment) gas-sensitive material prepared in Example 2 as raw material to 50 ppm ethanol. As can be seen from the graph, the response time and recovery time of the ZSM-5@In2O-B sensor after Ar / O2 plasma treatment to 50 ppm ethanol are significantly shortened compared with the untreated sensor, with a reduction of about 30-50%, indicating that plasma treatment effectively optimizes the gas adsorption and desorption kinetics.

[0068] Figure 19 The graph shows the response time and recovery time of a sensor prepared using ZSM-5@In2O3-C (after plasma treatment) gas-sensitive material prepared in Example 3 as raw material to 50 ppm ethanol. As can be seen from the graph, the ZSM-5@In2O-C sensor after Ar / O2 plasma treatment also exhibits rapid response / recovery characteristics, with its response time and recovery time shortened by 30-50% compared to the untreated sample, verifying the consistent modification effect of this surface treatment technology on composite materials with different ratios.

[0069] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for preparing a highly responsive ZSM-5@In2O3 gas-sensitive material resistant to silicon poisoning, characterized in that, Includes the following steps: (1) Indium salt and structure directing agent were dissolved in anhydrous ethanol and reacted by solvothermal method to obtain precursor. After washing, drying and calcination, In2O3 nanopowder with multi-level flower structure was obtained. (2) The In2O3 nanoparticles and ZSM-5 molecular sieve obtained in step (1) are dispersed in anhydrous ethanol and then mixed, magnetically stirred, and calcined a second time to obtain the composite material; (3) The composite material prepared in step (2) is placed in a plasma cleaner and Ar / O2 mixed gas is introduced for plasma treatment to obtain a high-response ZSM-5@In2O3 gas-sensitive material resistant to silicon poisoning.

2. The preparation method according to claim 1, characterized in that, In step (1), the mass ratio of the indium salt to the structure directing agent is (0.3~1):(1.61~3.22); wherein the indium salt is selected from indium chloride or indium nitrate; and the structure directing agent is obtained by compounding urea and sodium hexadecyl sulfate in a mass ratio of (0.36~0.72):(1.25~2.5).

3. The preparation method according to claim 2, characterized in that, In step (1), the temperature of the solvothermal reaction is 160°C and the time is 24 hours.

4. The preparation method according to claim 1, characterized in that, In step (1), the temperature of the first calcination is 500~600℃ and the time is 2~3 hours.

5. The preparation method according to claim 1, characterized in that, In step (2), the mass ratio of the In2O3 nanoparticles to the ZSM-5 molecular sieve is (17~19): (1~3).

6. The preparation method according to claim 1, characterized in that, In step (2), the magnetic stirring time is 3 hours; The secondary calcination temperature is 400℃ and the time is 2 hours.

7. The preparation method according to claim 1, characterized in that, In step (3), the volume ratio of Ar to O2 in the Ar / O2 mixed gas is (1~3):

1.

8. The preparation method according to claim 1, characterized in that, In step (3), the power of the plasma treatment is 50~150W and the treatment time is 5~15 minutes.

9. A highly responsive ZSM-5@In2O3 gas-sensitive material resistant to silicon poisoning, prepared by the preparation method according to any one of claims 1 to 8.

10. The application of the high-response ZSM-5@In2O3 gas-sensitive material with silicon poisoning resistance as described in claim 9 in a silicon poisoning resistance sensor.

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