Method for improving room-temperature gas-sensitive performance of metal oxide semiconductor sensitive material

Abstract

The invention discloses a method for improving the room-temperature gas-sensitive property of a metal oxide semiconductor sensitive material, which comprises the following steps of: uniformly placing the metal oxide semiconductor sensitive material on a pressing plate of a rotary shearing machine, and then applying pressure to the metal oxide semiconductor sensitive material until the target pressure is reached; and then directly standing or standing after high-pressure torsion, and finally relieving the pressure to obtain the metal oxide semiconductor sensitive material after high-pressure treatment or high-pressure shearing treatment. The high-pressure torsion is to rotate a side chopping board and apply different shear revolutions to the metal oxide semiconductor sensitive material. The sensitive material rich in crystal defects and bulk strain is successfully prepared through a high-pressure technology or a high-pressure torsion technology, more active sites are provided for gas molecule adsorption and reaction, crystal field distortion is induced to change the electronic structure of the material, and therefore the response performance of the sensitive material to specific gas is improved, and the sensitivity of the sensitive material to the specific gas is improved. And the gas-sensitive material has excellent gas-sensitive selectivity in various gas tests.

Description

Technical Field

[0001] The present invention relates to the technical field of gas detection, and in particular to a method for improving the room-temperature gas-sensing performance of a metal oxide semiconductor sensitive material. Background Art

[0002] Metal oxide semiconductor sensitive materials are widely used in the preparation of various commercial gas sensors due to their advantages such as high sensitivity, fast response speed, good stability, and low cost. They have a long history of application in the field of gas sensing. Early research focused on exploring the gas-sensing properties of different metal oxide materials. Common metal oxide materials include SnO2, ZnO, TiO2, WO3, CuO, In2O3, Co3O4, Fe2O3, and composite materials. These materials have been used to detect a variety of gases. However, these materials generally require higher temperatures to work effectively, which limits their application in certain environments, such as combustible gas detection. Therefore, traditional metal oxide gas sensing materials have the performance defects of low room temperature sensitivity and poor selectivity, which have become bottlenecks restricting their application. The response value and selectivity at room temperature still need to be improved.

[0003] The development of metal oxide semiconductor sensitive materials and their room temperature sensing performance shows a shift from high temperature operation to room temperature operation, and a development trend from single materials to composite materials and heterojunction structures. Chinese patent CN106018489A discloses a composite metal oxide material for detecting organic amine volatile gases. First, a simple co-precipitation method and hydrothermal treatment are used to prepare a multi-metal hydroxide precursor, and then high temperature calcination is used to obtain M Ⅱ O / M Ⅱ x M Ⅲ y O z Composite metal oxide materials, uniformly coated on the device surface by coating and then aged, yield a composite gas sensor capable of rapid detection of organic amine gases and exhibiting good selectivity for volatile organic amine gases. However, existing research still faces challenges such as high-temperature operation limitations, low sensitivity and selectivity at room temperature, difficulty in precise material preparation, and poor test stability and anti-interference performance. Future research should focus on developing new materials and exploring novel material preparation methods to achieve low-temperature, high-responsiveness sensing, pushing metal oxide-based gas sensors toward room-temperature, low-power, high-selectivity, and high-stability performance. Summary of the Invention

[0004] The present invention aims to provide a method for improving the room-temperature gas-sensing performance of metal oxide semiconductor (MOS) materials. This method addresses the limitations of these materials, which include high-temperature operation, low room-temperature sensitivity and selectivity, difficulty in precise material preparation, and poor testing stability and anti-interference performance. Using high-pressure technology, or high-pressure torsion (HPT), the present invention successfully prepares gas-sensing materials rich in crystal defects and bulk strain. This provides more active sites for gas molecule adsorption and reaction, and induces crystal field distortion, altering the material's electronic structure and thereby improving its gas response.

[0005] To achieve the above object, the first aspect of the present invention provides a method for improving the room temperature gas sensing performance of a metal oxide semiconductor sensitive material, comprising the following steps: The metal oxide semiconductor sensitive material is evenly placed on the pressure plate of the rotary shearing machine, and then pressure is applied to the metal oxide semiconductor sensitive material until the target pressure is reached, and then the material is allowed to stand, and finally the pressure is removed to obtain the metal oxide semiconductor sensitive material after high pressure treatment.

[0006] Preferably, the target pressure is 0~1000kN.

[0007] Preferably, the pressure is gradually increased at a fixed pressure increment rate, and the speed of applying pressure is 45-55 kN / h.

[0008] Preferably, the standing time is 0 to 10 hours.

[0009] The second aspect of the present invention provides a method for improving the room temperature gas-sensitive performance of metal oxide semiconductor sensitive materials. The metal oxide semiconductor sensitive material is evenly placed on the pressure plate of a rotary shearing machine, and then pressure is applied to the metal oxide semiconductor sensitive material until the target pressure is reached. Thereafter, the side anvil of the rotary shearing machine is rotated to apply different shearing speeds to the metal oxide semiconductor sensitive material. After the rotation is completed, it is allowed to stand, and finally the pressure is released to obtain the metal oxide semiconductor sensitive material after high-pressure shearing treatment.

[0010] Preferably, the target pressure is 0-1000 kN, the pressure is gradually increased at a fixed pressure increment rate, the pressure application rate is 45-55 kN / h, and the target pressure is 0-1000 kN.

[0011] Preferably, the shearing revolutions are 0 to 2 revolutions.

[0012] Preferably, the standing time is 0 to 10 hours.

[0013] The metal oxide semiconductor sensitive materials in the present invention include common SnO2, ZnO, TiO2, WO3, CuO, In2O3, Co3O4, Fe2O3 and composite materials.

[0014] The third aspect of the present invention provides a metal oxide semiconductor sensitive material prepared by the above method.

[0015] Preferably, the sensitive material after high-pressure torsion (high-pressure shear) treatment exhibits a complex defect structure, including: (1) linear defects (dislocation arrays and nanoscale corrugations); (2) planar defects (superdislocation networks); and (3) obvious lattice distortion.

[0016] A fourth aspect of the present invention provides an application of a metal oxide semiconductor sensitive material, and an application of the metal oxide semiconductor sensitive material in single gas detection.

[0017] Preferably, the metal oxide semiconductor sensitive material after high pressure treatment or the metal oxide semiconductor sensitive material after high pressure shear treatment is dispersed in ethanol to obtain a dispersion, and the dispersion droplets are applied to the interdigitated electrodes with a pipette and then allowed to stand and dry to obtain a chemical resistance gas sensor for specific gas detection.

[0018] Therefore, the present invention adopts a method for improving the room temperature gas sensing performance of a metal oxide semiconductor sensitive material using the above structure, which has the following beneficial effects: (1) This invention utilizes high pressure or high pressure shear technology to physically modify metal oxide semiconductor sensitive materials, and further explores their electronic structure changes and gas sensing properties. Under high pressure mechanical load, the sensitive materials form high-density and diverse microstructures, such as dislocations and stacking faults. These crystal defects can cause the inorganic metal oxide to transition to plasticity, changing the electronic structure of the material. On the one hand, lattice stress induces distortion, resulting in the Jahn-Teller effect and reducing lattice symmetry; on the other hand, the enriched microstructure provides active sites for gas molecule adsorption and reaction, thereby improving gas sensing performance.

[0019] (2) The present invention uses a metal oxide semiconductor sensitive material processed by high-pressure shear technology (high-pressure torsion technology, HPT technology) to construct a room-temperature detection chemiresistive gas sensor. This sensitive material is similar to the olfactory nerve in the human nasal cavity. It achieves specificity for gas molecules through a selective amplification process, exhibits ultra-sensitive specific gas detection capabilities at room temperature, and shows excellent gas sensitivity selectivity in multiple gas tests.

[0020] (3) The metal oxide semiconductor sensitive material processed by the high-voltage torsion technology of the present invention is used as a gas sensor, which has excellent selectivity, high cross-sensitivity and strong response ability, conforms to the development trend of green environmental protection, and achieves the coordinated unity of economic benefits, social benefits and environmental benefits.

[0021] (4) The metal oxide semiconductor sensitive material processed by the high-pressure torsion technology of the present invention has excellent sensing performance, which not only provides a new idea for the development of a new generation of room-temperature metal oxide semiconductor sensitive material gas sensors, but also provides an important reference for the physical modification of metal oxide semiconductor sensitive materials by HPT technology and the preparation of gas-sensitive materials rich in crystal defects and volume strain.

[0022] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Schematic diagram of the method of the present invention; Figure 2 TEM images and corresponding lattice images of samples of Example 1-1 to Example 1-3, where a. ZnO, b. ZnO-300, c. ZnO-300R and d. ZnO-300R 3 / 2 ; Figure 3 ZnO-300R 3 / 2 Rietveld refinement of the X-ray diffraction patterns of the samples; Figure 4 For ZnO and ZnO-300R 3 / 2 Selective responses of the sample to six different gases at a concentration of 100 ppm; Figure 5 ZnO-300R 3 / 2 Response of samples to different acid gases at 100 ppm concentration; Figure 6 ZnO-300R 3 / 2 Dynamic response characteristics of samples to different concentrations of HCl gas; Figure 7 ZnO-300R 3 / 2 Linear fitting curve of sample response to different concentrations of HCl gas and concentration; Figure 8 ZnO-300R 3 / 2 Cyclic response stability test curve of the sample to 10ppm HCl gas; Figure 9 ZnO-300R 3 / 2 Response and recovery time characteristic curve of the sample to 100ppm HCl gas; Figure 10 TEM images and corresponding lattice images of the samples of Example 2-1 and Example 2-2, wherein a. SnO2, b. SnO2-600, c. SnO2-600R; Figure 11X-ray diffraction patterns of the samples of Example 2-1 and Example 2-2, wherein a. SnO2, b. SnO2-600, c. SnO2-600R; Figure 12 Selective responses of SnO2-600R sample to seven different gases at 100 ppm concentration; Figure 13 The dynamic response characteristics of SnO2-600R sample to formic acid gas of different concentrations; Figure 14 The linear fitting curve of SnO2-600R sample's response to different concentrations of formic acid gas and its concentration; Figure 15 This is the cyclic response stability test curve of the SnO2-600R sample to 100ppm formic acid gas; Figure 16 This is the response and recovery time characteristic curve of SnO2-600R sample to 100ppm formic acid gas. DETAILED DESCRIPTION

[0024] The present invention will be further described below. It should be noted that this embodiment is based on the technical solution and provides a detailed implementation method and specific operation process, but the present invention is not limited to this embodiment.

[0025] Example 1-1 like Figure 1 As shown, a method for improving the room temperature gas sensing performance of metal oxide semiconductor sensitive materials using high voltage technology includes the following steps: 0.3 g of nano zinc oxide (ZnO, 99.9 wt %, purchased from Shanghai Aladdin Co., Ltd.) powder was evenly placed on the pressing plate of the press, and the press was activated to apply pressure to the sample. The pressure was gradually increased at a rate of 50 kN / h until it reached 300 kN. Under continuous target pressure, the sample was maintained at the target pressure for 1 hour, and finally the pressure was removed to obtain the high-pressure treated sample ZnO-300.

[0026] Example 1-2 like Figure 1 As shown, a method for improving the room temperature gas sensing performance of metal oxide semiconductor sensitive materials using high voltage torsion technology includes the following steps: 0.3 g of nano zinc oxide (ZnO, 99.9 wt%, purchased from Shanghai Aladdin Co., Ltd.) powder was evenly placed on the pressing plate of the press, and the press was activated to apply pressure to the sample. The pressure was gradually increased at a rate of 50 kN / h until the target pressure of 150 kN was reached. Under the continuous pressure of the target pressure, the anvil on the side of the sample was rotated to apply a shear force of 1 revolution to the sample. The sample was kept at the target pressure for 1 hour, and finally the pressure was removed to obtain the sample ZnO-150R after high-pressure shear treatment.

[0027] The target pressures in this embodiment were replaced with 300 kN, 450 kN, and 600 kN, respectively. The other steps were the same as the above process, and finally the samples ZnO-300R, ZnO-450R, and ZnO-600R after high-pressure shear treatment were obtained.

[0028] Examples 1-3 like Figure 1 As shown, a method for improving the room temperature gas sensing performance of metal oxide semiconductor sensitive materials using high voltage torsion technology includes the following steps: 0.3 g of nano zinc oxide (ZnO, 99.9 wt%, purchased from Shanghai Aladdin Co., Ltd.) powder was evenly placed on the pressing plate of the press. The press was activated to apply pressure to the sample. The pressure was gradually increased at a rate of 50 kN / h until the target pressure of 300 kN was reached. Under the continuous pressure of the target pressure, the anvil on the side of the sample was rotated to apply a shear force of 1 / 4 turn to the sample. The sample was kept under the target pressure for 1 hour. Finally, the pressure was removed to obtain the sample ZnO-300R after high-pressure shear treatment. 1 / 4 .

[0029] The shear speed in this example is replaced with 1 / 2, 3 / 2, and 2, and the other steps are the same as the above process, and finally the sample ZnO-300R after high pressure shear treatment is obtained. 1 / 2 、ZnO-300R 3 / 2 、ZnO-300R2.

[0030] Test Example 1 (1) The samples prepared in Examples 1-1 to 1-3 were subjected to TEM and XRD characterization.

[0031] from Figure 2 As can be seen, TEM analysis quantitatively shows a decrease in the size of the nanoparticles throughout the series, with ZnO being 19.62 nm, ZnO-300 being 18.89 nm, ZnO-300R being 17.48 nm, and ZnO-300R being 18.89 nm. 3 / 2 The lattice fringes are 15.42 nm and obvious lattice fringes can be observed in all samples. Figure 2The morphology and atomic level structural evolution under different processing conditions are systematically demonstrated. Figure 2 As shown in a, the original ZnO sample shows large particle agglomerates with clear particle boundaries. Figure 2 As shown in b, the ZnO-300 sample shows higher electron transparency and fuzzy edges under high pressure without torsion, indicating that the structure has changed. Figure 2 As shown in Figure c, under the conditions of high pressure and torsion, some particles of the ZnO-300R sample were broken and the particle size was slightly reduced. Figure 2 As shown in Figure d, this size reduction trend intensifies with the increase of the torsion period. HR-TEM analysis further reveals the different atomic-level structural evolutions in the treated samples. Figure 2 As shown in a, the lattice fringe spacing of the ZnO raw material is 0.26nm. Figure 2 d shows ZnO-300R treated with HPT 3 / 2 The samples exhibit complex defect structures, including linear defects (dislocation arrays and nanoscale corrugations), planar defects (superdislocation networks), and obvious lattice distortions.

[0032] from Figure 3 As can be seen, the model of sensitive materials was simulated, optimized and refined using powder X-ray diffraction (XRD) combined with theoretical calculation structure simulation (Materials Studio and first principle simulation package (vasp)), and the crystal structure of the material was further characterized. wp =8.58%, R wp (w / o back) = 9.07%) showed excellent convergence, and both values ​​were below the empirical 10% confidence threshold. All diffraction peaks showed an accurate correspondence with the standard JCPDS card (PDF#36-1451), confirming the phase purity and structural integrity. 3 / 2 The lattice compression is significant. By comparing the experimental (d0) and standard (d s ) interplanar spacing, the macroscopic compressive strain was quantified, and the average strain value ε = 0.0115±0.002 was obtained.

[0033] (2) Testing the gas sensing performance of sensitive materials The testing process is as follows: 10mg of ZnO-300R treated with high pressure torsion technology 3 / 2 The nano-sensitive material was dispersed in 0.1 ml of anhydrous ethanol solution and ultrasonicated for 30 minutes to obtain ZnO-300R treated by high-pressure torsion technology. 3 / 2 Dispersion, use a pipette to add 10uL of treated ZnO-300R3 / 2 The ethanol solution was drop-coated on the interdigitated electrodes, and the resulting electrodes were dried and allowed to stand at room temperature for 3 minutes to obtain a gas sensor device of the sample to be tested. The sample was tested for sensing performance using a static testing system during the device gas sensing performance test.

[0034] First, the above sample was placed in a 1L sealed glass bottle as a sensor device (denoted as gas bottle A, the internal gas environment is air). The current value of the device was monitored by the CHI660e electrochemical workstation. After the current signal of the device in gas bottle A stabilized, it was quickly transferred to a 1L sealed glass bottle containing a certain concentration of HCl gas (denoted as gas bottle B. According to the liquid gas distribution formula, the volume of HCl solution with a certain concentration was calculated, added to bottle B, heated to completely evaporate the HCl solution into a gaseous state, and the test was started after cooling to room temperature). After the current of the device in gas bottle B also reached a sufficiently stable value, the sensor was quickly transferred back to gas bottle A. In addition, during the gas test, the two glass bottles were cleaned by continuously vacuuming the gas bottle for 5 minutes. The bias voltage of the sensor was 1V, and the current was recorded using the CHI660e electrochemical workstation. Responsivity (R) is used to evaluate the effect of HCl gas on the response, and the calculation formula is: R=ΔI / I0×100%, Where I0 is the current value of the sensor in air, and ΔI represents the change in the current value in the circuit after the sensor is exposed to the analytical gas.

[0035] The sensing properties of gas-sensitive materials determine the working performance of gas sensors, and selectivity is an important criterion for evaluating sensor performance. This basic parameter reflects the ability of the sensor to specifically recognize the target analyte while maintaining minimal cross-response to interfering substances. Preliminary screening experiments with pristine ZnO materials, such as Figure 4 The response to ammonia (100 ppm) is 63.55%, and the cross-sensitivity to the other five gases (acid, aldehyde, ketone, alcohol and benzene) cannot be ignored, indicating that the anti-interference ability is insufficient. 3 / 2 A remarkable selectivity modulation was induced, which significantly reduced the ammonia response (20.18%) and enhanced the acid sensitivity (213.79% for HCl), while effectively suppressing the response to other interfering gases.

[0036] Table 1 Response results of gas-sensitive materials to various gases Original ZnO <![CDATA[ZnO-300R 3 / 2 ]]> hydrochloric acid 14.67% 213.79% Toluene 2% - Ammonia 63.55% 5% ethanol 9.55% 2% acetone 4.74% - acetaldehyde 5% - Furthermore, a systematic optimization scheme was implemented to maximize HCl detection performance. Pressure-dependent studies under HPT conditions with a fixed shear force of 1 revolution revealed a volcano relationship, with the optimal response (128.29%) achieved at 300 kN. Subsequent shear force optimization at this optimal pressure of 300 kN demonstrated that a 3 / 2 revolution HPT treatment produced the greatest response enhancement (213.79%), consistent with a typical volcano-type trend with increasing torsional strength.

[0037] In order to systematically study ZnO-300R 3 / 2 To investigate the acid-selective conversion of samples, we conducted a comprehensive screening of seven acidic substances (hydrochloric acid (HCl), formic acid (HCOOH), acetic acid (CHCOOH), propionic acid (CH3CH2COOH), lactic acid (C3H6O3), hydrofluoric acid (HF) and phosphoric acid (H3PO4)) at equal concentrations (100 ppm). Figure 5 As shown, ZnO-300R 3 / 2 It exhibited excellent HCl selectivity with a response amplitude of 213.79%, which was in sharp contrast to the minimal response to other acids (<8%). These findings collectively indicate that HPT-treated ZnO-300R 3 / 2 The strain-engineered ZnO material exhibits three key advances in HCl detection: (1) excellent target sensitivity (213.79% response at 100 ppm); (2) superior chemical selectivity against multiple interferences; and (3) excellent interference rejection. The performance of this strain-engineered ZnO material demonstrates significant potential for reliable HCl monitoring in complex multi-analyte environments and represents a significant advance in the development of selective gas sensors.

[0038] from Figure 6 It can be seen that in determining ZnO-300R 3 / 2 After the optimal HCl detector was obtained, the system evaluated its sensing characteristics with concentration changes. In the HCl concentration range from 100ppm to 5ppm, the linear response of the sensor decreased from 213.79% to 9.96%. This shows that ZnO-300R 3 / 2 It has good response to HCl concentration.

[0039] from Figure 7 As can be seen in the figure, there is a strong linear correlation between gas concentration and response intensity (R²=0.998), which allows the derivation of first-order kinetic parameters. It is worth noting that the calculated detection limit (LOD) reaches 234 ppb, showing that the detection of trace levels is possible for sample ZnO-300R. 3 / 2 Has excellent low concentration detection capabilities.

[0040] from Figure 8As can be seen from the graph, the sensor maintained 91.3% response retention (21.2% initial response vs. 19.35% final response) after five consecutive tests under 10 ppm HCl conditions, demonstrating negligible sensitivity degradation and remarkable cycling stability, which is crucial for practical applications.

[0041] from Figure 9 As can be seen in the figure, after exposure to HCl gas environment, the signal quickly saturated to 90% within 24.3 seconds, and the baseline recovery rate was 21.7 seconds at 100 ppm, indicating effective gas-surface interaction and reversible adsorption-desorption kinetics. This fast response / recovery time is very beneficial for improving the real-time response of the sensor.

[0042] The above results show that ZnO-300R treated with HPT 3 / 2 The material has excellent HCl gas adsorption and desorption properties, and has excellent characteristics such as fast recovery speed, strong anti-interference ability, and short response time. These characteristics synergistically play the advantages of 4S (sensitivity, speed, stability and specificity), and HPT modified ZnO-300R 3 / 2 The sensor is positioned as a reliable platform for HCl monitoring in complex environments, significantly advancing the development of field-deployable gas sensing solutions with industrial-grade durability and accuracy.

[0043] Example 2-1 like Figure 1 As shown, a method for improving the room temperature gas sensing performance of metal oxide semiconductor sensitive materials using high voltage technology includes the following steps: 0.3 g of nano-tin oxide (SnO2, 99.9 wt%, purchased from Shanghai Aladdin Co., Ltd.) powder was evenly placed on the pressing plate of the press, and the press was activated to apply pressure to the sample. The pressure was gradually increased at a rate of 50 kN / h until it reached 600 kN. Under continuous target pressure, the sample was maintained at the target pressure for 1 hour, and finally the pressure was removed to obtain the high-pressure treated sample SnO2-600.

[0044] Example 2-2 like Figure 1 As shown, a method for improving the room temperature gas sensing performance of metal oxide semiconductor sensitive materials using high voltage torsion technology includes the following steps: 0.3 g of nano-tin oxide (SnO2, 99.9 wt%, purchased from Shanghai Aladdin Co., Ltd.) powder was evenly placed on the pressing plate of the press, and the press was activated to apply pressure to the sample. The pressure was gradually increased at a speed of 50 kN / h until the target pressure of 300 kN was reached. Under the continuous pressure of the target pressure, the anvil on the side of the sample was rotated to apply a shear force of 1 revolution to the sample. The sample was kept at the target pressure for 1 hour, and finally the pressure was removed to obtain the sample SnO2-300R after high-pressure shear treatment.

[0045] The target pressures in this embodiment were replaced with 600 kN and 800 kN, respectively. The other steps were the same as the above process, and finally the samples SnO2-600R and SnO2-800R after high-pressure shear treatment were obtained.

[0046] Test Example 2 (1) The sensitive materials prepared in Example 2-1 and Example 2-2 were subjected to TEM and XRD characterization.

[0047] from Figure 10 As can be seen in Figure 3, TEM analysis quantitatively shows the size reduction of the nanoparticles in the entire series, and clear lattice fringes can be observed in all samples. The morphology and atomic level structural evolution under different processing conditions are systematically demonstrated. Figure 10 As shown in a, the original SnO2 sample shows large particle clusters with clear particle boundaries. Figure 10 As shown in b, the SnO2-600 sample shows higher electron transparency and fuzzy edges under high pressure without twisting, indicating that the structure has changed. Under the conditions of high pressure and twisting, Figure 10 As shown in (c), the SnO2-600R sample showed partial particle fragmentation and particle size reduction. HR-TEM analysis further revealed different atomic-level structural evolutions in the treated samples.

[0048] from Figure 11 As can be seen in the figure, the material's crystal structure was further characterized using powder X-ray diffraction (XRD). All diffraction peaks show precise correspondence with the standard JCPDS card (PDF#41-1445), confirming phase purity and structural integrity. Comparative analysis reveals significant lattice compression in SnO2-600R after high-pressure shearing.

[0049] (2) Testing the gas sensing performance of sensitive materials The testing process is as follows: 10 mg of SnO2-600R nanosensor material treated with high-pressure torsion was dispersed in 0.1 ml of anhydrous ethanol solution and subjected to ultrasonication for 30 minutes to obtain a SnO2-600R dispersion treated with high-pressure torsion. 10 μL of the treated SnO2-600R ethanol solution was then drop-coated onto interdigital electrodes using a pipette. The resulting electrodes were dried at room temperature and allowed to stand for 3 minutes to obtain a gas sensor device. The sample was then tested for sensing performance using a static testing system.

[0050] First, the above sample was placed in a 1L sealed glass bottle as a sensor device (denoted as gas bottle A, the internal gas environment is air). The current value of the device was monitored by the CHI660e electrochemical workstation. After the current signal of the device in gas bottle A stabilized, it was quickly transferred to a 1L sealed glass bottle containing a certain concentration of formic acid gas (denoted as gas bottle B. According to the liquid gas distribution formula, the volume of the solution of formic acid with a certain concentration was obtained, added to bottle B, heated to completely evaporate the formic acid solution into a gaseous state, and the test was started after cooling to room temperature). After the current of the device in gas bottle B also reached a sufficiently stable value, the sensor was quickly transferred back to gas bottle A. In addition, during the gas test, the two glass bottles were cleaned by continuously vacuuming the gas bottle for 5 minutes. The bias voltage of the sensor was 1V, and the current was recorded using the CHI660e electrochemical workstation. The responsiveness (R) is used to evaluate the effect of formic acid gas on the response, and the calculation formula is: R=ΔI / I0×100%, Where I0 is the current value of the sensor in air, and ΔI represents the change in the current value in the circuit after the sensor is exposed to the analytical gas.

[0051] The sensing properties of gas-sensitive materials determine the working performance of gas sensors, and selectivity is an important criterion for evaluating sensor performance. This basic parameter reflects the ability of the sensor to specifically identify the target analyte while maintaining minimal cross-response to interfering substances. Preliminary screening experiments using original SnO2 material and SnO2-600R material, such as Figure 12 The results show that the response to formic acid (100 ppm) is 151.63%, and the cross-sensitivity to the other six gases is very low, showing excellent anti-interference ability.

[0052] Table 2 Response results of gas-sensitive materials to different gases <![CDATA[Original SnO2]]> <![CDATA[SnO2-600R]]> acetone - - Toluene - - hydrofluoric acid - - acetaldehyde - - Formic acid 32% 151.63% Ammonia 8% 2% Methanol 52% 3% Furthermore, a systematic optimization scheme was implemented to maximize the detection performance of HCl. Pressure correlation studies under HPT conditions with a fixed shear force of 1 revolution revealed a volcano relationship, with the optimal response (151.63%) achieved at 600 kN.

[0053] from Figure 13 As can be seen in the figure, after determining SnO2-600R as the optimal formic acid detector, its sensing characteristics with concentration changes were systematically evaluated. In the formic acid concentration range from 100ppm to 5ppm, the linear response of the sensor decreased from 151.63% to 7.67%.

[0054] from Figure 14 It can be seen that there is a strong linear correlation between gas concentration and response intensity (R 2 =0.999), allowing the derivation of first-order kinetic parameters. Notably, the calculated limit of detection (LOD) reached 567 ppb, demonstrating trace-level monitoring and superior low-concentration detection capabilities.

[0055] from Figure 15 It can be seen that after five consecutive tests under 100 ppm formic acid conditions, the sensor maintained negligible sensitivity degradation and remarkable cyclic stability, which is crucial for practical applications.

[0056] from Figure 16 As can be seen in the figure, after exposure to formic acid gas environment, the signal quickly saturated to 90% within 8.5 seconds, and the baseline recovery rate was 8.8 seconds at 100 ppm, indicating effective gas-surface interaction and reversible adsorption-desorption kinetics. This fast response\recovery time is very beneficial for improving the real-time response of the sensor.

[0057] The above results show that the SnO2-600R material after HPT treatment has excellent formic acid gas adsorption and desorption performance, and has excellent characteristics such as fast recovery speed, strong anti-interference ability and short response time.

[0058] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the same. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solutions of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for improving the room temperature gas sensing performance of a metal oxide semiconductor sensitive material, characterized by: The following steps are involved: The metal oxide semiconductor sensitive material is evenly placed on the pressure plate of the rotary shearing machine, and then pressure is applied to the metal oxide semiconductor sensitive material until the target pressure is reached, and then the material is allowed to stand, and finally the pressure is removed to obtain the metal oxide semiconductor sensitive material after high pressure treatment.

2. The method for improving the room temperature gas sensing performance of a metal oxide semiconductor sensitive material according to claim 1, characterized in that: The target pressure is 0~1000kN.

3. The method for improving the room temperature gas sensing performance of a metal oxide semiconductor sensitive material according to claim 1, characterized in that: The pressure is gradually increased at a fixed pressure increment rate, and the pressure application rate is 45~55kN / h.

4. The method for improving the room temperature gas sensing performance of a metal oxide semiconductor sensitive material according to claim 1, characterized in that: The standing time is 0~10h.

5. A method for improving the room temperature gas sensing performance of a metal oxide semiconductor sensitive material, characterized by: The metal oxide semiconductor sensitive material is evenly placed on the pressure plate of the rotary shearing machine, and then pressure is applied to the metal oxide semiconductor sensitive material until the target pressure is reached. Then, the side anvil of the rotary shearing machine is rotated to apply different shearing revolutions to the metal oxide semiconductor sensitive material. After the rotation is completed, it is allowed to stand and finally the pressure is released to obtain the metal oxide semiconductor sensitive material after high-pressure shearing treatment.

6. The method for improving the room temperature gas sensing performance of a metal oxide semiconductor sensitive material according to claim 5, characterized in that: The target pressure is 0~1000kN, and the pressure is gradually increased at a fixed pressure increment rate. The pressure application rate is 45~55kN / h, and the target pressure is 0~1000kN.

7. The method for improving the room temperature gas sensing performance of a metal oxide semiconductor sensitive material according to claim 5, characterized in that: The shearing rotation number is 0~2 rotations.

8. The method for improving the room temperature gas sensing performance of a metal oxide semiconductor sensitive material according to claim 5, characterized in that: The standing time is 0~10h.

9. A metal oxide semiconductor sensitive material, characterized in that: The method according to any one of claims 1 to 8 is used to prepare the present invention.

10. The use of a metal oxide semiconductor sensitive material according to claim 9, characterized in that: Application of metal oxide semiconductor sensitive materials in single gas detection.

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