Preparation method, temperature regulation and control method and application of tin oxide-based nanofiber gas sensor array

Abstract

The invention discloses a preparation method of a tin oxide-based nanofiber gas sensor array, a temperature regulation and control method and application of the tin oxide-based nanofiber gas sensor array. Firstly, different tin oxide-based nanofiber gas sensors are controllably prepared, and the gas sensing performance is optimized by adopting a temperature modulation technology; and finally, 11 VOCs (n-propanol, n-butanol, ethanol, triethylamine, formaldehyde, acetone, diethyl ether, benzene, toluene, ethylbenzene and m-xylene) gases are identified. According to the dynamic temperature control, the surface adsorption and desorption processes can be obviously influenced by changing the working temperatures of different metal oxide nanofiber sensors, so that the selective recognition of different gas molecules is realized. Besides, by reasonably designing the composition of the sensor array and a temperature control strategy, the characteristic information of different gas molecules can be effectively distinguished, and the accuracy and reliability of gas recognition are further improved.

Description

Technical Field

[0001] The present invention relates to the technical field of gas sensors, and more specifically to a temperature control method and application of a tin oxide-based nanofiber gas sensor array. Background Art

[0002] Volatile organic compounds (VOCs) are a class of volatile organic compounds, including a series of hydrocarbons and oxides, the most common of which are benzene, toluene, xylene, ethylene, etc. These compounds have potential risks to the environment and human health, such as carcinogenicity, neurotoxicity, respiratory diseases, etc. Therefore, detecting and monitoring the concentration and type of VOCs is crucial to environmental protection and human health. VOCs identification and detection technology is constantly developing, aiming to detect and identify VOCs more accurately and quickly, providing strong support for environmental protection and human health.

[0003] Metal oxide nanofibers have the characteristics of large specific surface area, high mechanical strength, good conductivity, and good gas sensitivity. They are a kind of nanomaterial with great application potential. They are widely used in sensors, catalysts, energy storage and other fields. In particular, metal oxide nanofibers prepared based on electrospinning technology have become one of the research hotspots due to their efficient and controllable preparation process and superior structural characteristics. In the field of gas sensors, metal oxide nanofibers have received special attention. Due to their high specific surface area and excellent electronic properties, they have become an ideal material for detecting harmful gases in the environment.

[0004] MOS gas sensors have the advantages of high sensitivity, low cost and convenient preparation, and have become an ideal choice for VOCs detection. However, in practical applications, MOS gas sensors are greatly affected by temperature. In the traditional constant temperature working mode, the response characteristics of gas sensors to different types of VOCs are relatively complex, resulting in low recognition accuracy. Therefore, dynamic temperature control technology is introduced in metal oxide nanofiber gas sensors, which can change the response characteristics of the sensor at different temperatures and improve the recognition accuracy. Through dynamic temperature control, the sensor can be measured at different temperatures to obtain more characteristic information of VOCs. The sensor may be more sensitive to some VOCs at lower temperatures and more sensitive to other VOCs at higher temperatures. Therefore, by constantly adjusting the temperature, more comprehensive and accurate VOC fingerprints and features can be obtained. The use of dynamic temperature-controlled MOS gas sensors can achieve more accurate and reliable identification of VOCs. This has broad application prospects in environmental monitoring, indoor air quality detection and other fields. However, this method also faces some challenges, such as how to determine the optimal temperature range and control strategy, and how to deal with mutual interference between different gases. Therefore, further research and optimization are still necessary and urgent.

[0005] However, single metal oxide nanofiber gas sensors are often affected by cross-sensitivity when identifying different gases, making it difficult to accurately detect specific gases. Summary of the invention

[0006] In order to solve this problem, it is proposed to use a gas sensor array to improve the recognition performance. A gas sensor array is a detection device that integrates multiple gas sensors and can simultaneously detect and identify the presence and concentration of multiple gases. This technology combines the advantages of electronic technology and chemical analysis. It can improve the accuracy and efficiency of gas detection by analyzing the interaction between the gas and the sensor surface to detect and identify different gases. Dynamic temperature control can significantly affect the surface adsorption and desorption process of different metal oxide nanofiber sensors by changing their operating temperature, thereby achieving selective recognition of different gas molecules. In addition, by rationally designing the composition of the sensor array and the temperature control strategy, the characteristic information of different gas molecules can be effectively distinguished, further improving the accuracy and reliability of gas identification.

[0007] The specific technical solutions of the present invention are as follows:

[0008] A method for preparing a tin oxide-based nanofiber gas sensor array comprises: preparing different tin oxide-based nanofiber gas sensors, specifically:

[0009] Material selection: The gas sensor array uses six sensors as components of the array, and the sensors are: SnO 2 NFs-1, SnO 2 NFs-2, Co 3 O 4 @SnO 2 、NiO@SnO 2 、CuO@SnO 2 、ZnO@SnO 2 ;

[0010] Substrate selection: Choose six-pin nickel-chromium substrate;

[0011] Preparation of sensitive film layer: The sensitive material is deposited on the substrate in the form of a thin film; during the preparation process, parameters such as temperature, atmosphere and pressure must be controlled to ensure the uniformity and consistency of the sensitive film layer;

[0012] Preparation of polar electrodes: Processing polar electrodes on the sensitive film layer to provide input and output of current and voltage;

[0013] Packaging protection: Packaging the prepared sensitive components to protect the sensitive film layer from interference from the external environment and impurities;

[0014] Connection and testing: Connect and fix the sensitive element to the external circuit and perform relevant tests. The testing process may involve measuring resistance, current and voltage, and evaluating the response to the target gas.

[0015] It should be noted that various parameters and conditions need to be strictly controlled during the preparation of the element to ensure the stability and reliability of the sensitive performance. In addition, in order to obtain better sensing performance, the performance of the sensor element can be further improved by regulating factors such as temperature, pressure, atmosphere, etc. during the preparation process, as well as optimizing the material and structural design.

[0016] The gas sensor is a MOS gas sensor;

[0017] (Pure SnO after thermal oxidation 2 NFs-1 nanofibers; chain-like SnO after thermal oxidation 2 NFs-2 nanofibers; (cf) thermally oxidized nanofibers embedded with different adsorbed ions (Co, Ni, Cu, Zn) 3 O 4 @SnO 2 、NiO@SnO 2 、CuO@SnO 2 、ZnO@SnO 2 ))

[0018] Preferably, in the present invention, a ceramic sheet is selected as the main structure of the sensor, the sensing element is mainly supported by a six-pin base, the gold electrode on the front of the heating ceramic plate is used as a test electrode, and the RuO 2 The resistor acts as a heating electrode to provide the required operating temperature for the target gas test.

[0019] Preferably, the manufactured sensor needs to be subjected to a stable aging treatment, generally by being properly stored under dry conditions for 12-24 hours.

[0020] (ii) A temperature control method for a tin oxide-based nanofiber gas sensor array, comprising: adjusting frequency, duty cycle, and voltage parameters.

[0021] Preferably, a Keithley 6487 picoammeter is used as voltage source and current reader, applying a membrane voltage of 5 V to the transducer and recording two values ​​per second.

[0022] Preferably, a RIGOL DP832A is used to apply a square wave pulse heating voltage to the resistance wire, and the parameters are as follows: low voltage 0V, high voltage 6.5V and 50% duty cycle; frequency adjustment range: 0.01Hz-0.05Hz.

[0023] (III) Dynamic gas sensing performance test of a tin oxide-based nanofiber gas sensor array

[0024] Preferably, the gas sensor is SnO 2 NFs-1, SnO 2 NFs-2, Co 3 O 4 @SnO 2 、NiO@SnO 2 、CuO@SnO 2 、ZnO@SnO 2 sensor.

[0025] Preferably, the sensing measurements are performed in a closed glass container (500 mL) equipped with appropriate gas flow inlet and outlet. Temperature modulated sensing of the detected gas is performed in dry air, and each measurement is repeated three or more times.

[0026] Preferably, the response is defined as S = R at a characteristic temperature point a / R g , where R a and R g They are the resistance in dry air and in the presence of the detected gas at the corresponding characteristic temperature points. Finally, the characteristic response curve of the target gas under temperature modulation is obtained by computer data acquisition. It should be emphasized that all gas sensing measurements are performed in dry air.

[0027] (4) A tin oxide-based nanofiber gas sensor array for the identification of 11 VOCs.

[0028] VOCs gas identification method is:

[0029] Preferably, LDA (Linear Discriminant Analysis) is used; and K-means algorithm is combined at the same time.

[0030] Preferably, the gas is identified and analyzed using quantitative analysis.

[0031] Technical effects and advantages of the present invention:

[0032] The present invention proposes a dynamic temperature modulation strategy, and specifically studies the dynamic temperature control sensitivity and sensing behavior of 6 different MOS gas sensors under different frequency modulation. According to the differences in their characteristic curves, linear discriminant analysis (LDA) is used for feature extraction and dimension reduction, and the results show the specificity of different sensors. At the same time, the gas concentration and response specifically identified by the gas sensor are calculated, and the specific functional relationship between them is found, which can be quantitatively analyzed. In addition, by combining 6 sensors into a sensor microarray, 11 different VOCs can be successfully identified and analyzed at a frequency modulation of 0.02Hz (low voltage 0V, high voltage 6.5V) and a duty cycle of 50%. . BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 Schematic diagram of the technical solution of the invention.

[0034] Figure 2 SEM images of different nanofibers and gas sensor images, (a) pure SnO after thermal oxidation 2 NFs-1 nanofibers; (b) beaded SnO after thermal oxidation 2 NFs-2 nanofibers; (cf) thermally oxidized nanofibers embedded with different adsorbed ions (Co, Ni, Cu, Zn) 3 O 4 @SnO 2 、NiO@SnO 2 、CuO@SnO 2 、ZnO@SnO 2 ).

[0035] Figure 3 Schematic diagram of the gas sensing element manufacturing process.

[0036] Figure 4 Schematic diagram of the dynamic temperature control test device.

[0037] Figure 5. Real-time working temperature curve of the sensor under 0.02Hz frequency control, (a) SnO 2 NFs-1; (b) SnO 2 NFs-2; (c)Co 3 O 4 @SnO 2 ; (d) NiO@SnO 2 ; (e) CuO@SnO 2 ; (f) ZnO@SnO 2

[0038] Figure 6Real-time characteristic response curves of 11 VOCs gases under 0.01Hz frequency control, (a1-a12) SnO 2 NFs-1;(b1-b12)SnO 2 NFs-2;(c1-c12)Co 3 O 4 @SnO 2 ; (d1-d12)NiO@SnO 2 ; (e1-e12)CuO@SnO 2 ; (f1-f12) ZnO@SnO 2

[0039] Figure 7 Real-time characteristic response curves of 11 VOCs gases under 0.02Hz frequency control, (a1-a12) SnO 2 NFs-1;(b1-b12)SnO 2 NFs-2;(c1-c12)Co 3 O 4 @SnO 2 ; (d1-d12)NiO@SnO 2 ; (e1-e12)CuO@SnO 2 ; (f1-f12) ZnO@SnO 2

[0040] Figure 8 Real-time characteristic response curves of 11 VOCs gases under 0.03Hz frequency control, (a1-a12) SnO 2 NFs-1;(b1-b12)SnO 2 NFs-2;(c1-c12)Co 3 O 4 @SnO 2 ; (d1-d12)NiO@SnO 2 ; (e1-e12)CuO@SnO 2 ; (f1-f12) ZnO@SnO 2

[0041] Fig. 9 Real-time characteristic response curves of 11 VOCs gases under 0.04Hz frequency control, (a1-a12) SnO 2 NFs-1;(b1-b12)SnO 2 NFs-2;(c1-c12)Co 3 O 4 @SnO 2 ; (d1-d12)NiO@SnO 2; (e1-e12)CuO@SnO 2 ; (f1-f12) ZnO@SnO 2

[0042] Fig.10 Real-time characteristic response curves of 11 VOCs gases under 0.05Hz frequency control, (a1-a12) SnO 2 NFs-1;(b1-b12)SnO 2 NFs-2;(c1-c12)Co 3 O 4 @SnO 2 ; (d1-d12)NiO@SnO 2 ; (e1-e12)CuO@SnO 2 ; (f1-f12) ZnO@SnO 2

[0043] Fig.11 Results of the six sensor array outputs at 0.02 Hz frequency modulation, successfully identifying 11 VOCs (a) 3D LDA output results; (b) HCA output results. DETAILED DESCRIPTION

[0044] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0045] like Figure 1 The figure shows a schematic diagram of the technical solution of the invention. First, different tin oxide-based nanofiber gas sensors can be prepared, and the temperature modulation technology is used to optimize the gas sensing performance. Finally, the purpose of identifying 11 VOCs (n-propanol, n-butanol, ethanol, triethylamine, formaldehyde, acetone, ether, benzene, toluene, ethylbenzene, and m-xylene) gases can be achieved.

[0046] The technical solution of the present invention mainly includes the following parts:

[0047] (I) Fabrication of different tin oxide-based nanofiber gas sensors

[0048] The preparation of the tin oxide-based nanofiber gas sensor of the present invention involves the following key steps:

[0049] 1. Material selection: First, we need to select sensitive materials suitable for specific gas sensing applications. The choice of materials depends on the type of gas to be detected and the target application. 2NFs-1 nanofibers; chain-like SnO after thermal oxidation 2 NFs-2 nanofibers; (cf) thermally oxidized nanofibers embedded with different adsorbed ions (Co, Ni, Cu, Zn) 3 O 4 @SnO 2 、NiO@SnO 2 、CuO@SnO 2 、ZnO@SnO 2 )) As gas sensitive sensing materials, such as Figure 2 shown.

[0050] 2. Substrate selection: Select a suitable substrate material according to the properties of the sensitive material and the requirements of the preparation method. The present invention selects a six-pin nickel-chromium substrate.

[0051] 3. Preparation of sensitive film layer: The sensitive material is usually deposited on the substrate in the form of a thin film. During the preparation process, parameters such as temperature, atmosphere and pressure must be controlled to ensure the uniformity and consistency of the sensitive film layer.

[0052] 4. Preparation of polar electrodes: Process polar electrodes on the sensitive film layer to provide input and output of current and voltage.

[0053] 5. Packaging protection: The prepared sensitive components are packaged to protect the sensitive film layer from interference from the external environment and impurities.

[0054] 6. Connection and testing: Connect and fix the sensitive element to the external circuit and perform relevant tests. The testing process may involve measuring resistance, current and voltage, and evaluating the response to the target gas.

[0055] It should be noted that various parameters and conditions need to be strictly controlled during the preparation of the element to ensure the stability and reliability of the sensitive performance. In addition, in order to obtain better sensing performance, the performance of the sensor element can be further improved by regulating factors such as temperature, pressure, atmosphere, etc. during the preparation process, as well as optimizing the material and structural design.

[0056] In the present invention, a ceramic sheet is selected as the main structure of the sensor, which is very common in the field of gas sensing. Figure 3 The basic structure of the sensor is shown: the sensing element is mainly supported by a six-pin base, the gold electrode on the front of the heated ceramic plate is used as a test electrode, and the RuO 2The resistor is used as a heating electrode to provide the required operating temperature for the target gas test. When manufacturing the sensor, it is necessary to select a translucent nanofiber membrane of appropriate size and thickness as the material of the gas sensing element. In general, the differences in the materials of different gas sensing elements are mainly reflected in their sensitive properties and their applications in sensor manufacturing. In practical applications, it is crucial to select suitable gas-sensitive materials according to the specific needs of the sensor. It is worth noting that in order to ensure the stability of the experiment, the sensors that have been manufactured need to be subjected to a stable aging treatment, which generally lasts for 12-24 hours under dry conditions for proper storage. After completing the corresponding steps, the gas sensor can perform the corresponding experimental operations.

[0057] (2) Parameter control of temperature modulation technology

[0058] The present invention uses a Keithley 6487 picoammeter as a voltage source and current reader, applies a membrane voltage of 5V to the transducer, and records two values ​​per second. A square wave pulse heating voltage is applied to the resistance wire using a RIGOL DP832A, and the parameters are as follows: low voltage 0V, high voltage 6.5V and 50% duty cycle; frequency adjustment range: 0.01Hz-0.05Hz. Different frequencies exhibit different temperature changes at this voltage. The sensing measurement is carried out in a closed glass container (500mL) equipped with appropriate airflow inlet and outlet. The detected gas is subjected to temperature modulated sensing behavior in dry air, and each measurement is repeated more than three times. Here, the response is defined as S=R at the characteristic temperature point. a / R g , where R a and R g are the resistance in dry air and in the presence of the detected gas at the corresponding characteristic temperature point. Finally, the characteristic response curve of the target gas under temperature modulation is obtained by collecting data through a computer. It should be emphasized that all gas sensing measurements are performed in dry air. See the specific invention equipment flow chart Figure 4 .

[0059] (3) Dynamic gas sensing performance test

[0060] This invention will explain the differences in temperature changes under different frequency regulation. Figure 5The real-time working temperature curves of different sensors under 0.02Hz frequency modulation are shown in detail. In general, different sensors have different sensing temperature ranges, and the temperature ranges of the sensors are 38.2-444.1℃, 38.1-444.9℃, 39.4-440.1℃, 42.5-440.1℃, 42.3-443.5℃ and 39.5-442.9℃ respectively. Temperature plays a vital role in dynamic temperature control. First of all, temperature can affect the movement speed of gas molecules and the chemical reaction speed inside the substance. At lower temperatures, the molecular movement speed is slower, and the chemical reaction speed is also slower, resulting in a slower change in the material properties on the surface of gas molecules. At higher temperatures, the molecular movement speed is faster, and the chemical reaction speed is also faster, resulting in a faster change in the properties of gas molecules. Therefore, by changing the temperature, the reaction degree of the molecules on the gas surface can be controlled, and the characteristics of the gas molecules can be exposed to a greater extent, which provides strong support for the subsequent specific identification of different target gases.

[0061] It is worth noting that the six sensors have slightly different temperature ranges due to their own differences, but the error is controlled within 5°C, which ensures the consistency of temperature changes for subsequent tests of different VOCs gases using different sensors. Figure 5 It can be seen that the heating rate and cooling rate of different sensors under 0.02Hz frequency modulation are consistent. At the same time, it can be concluded that these real-time working temperature curves are stable, continuous and periodic.

[0062] Example 1: Using a Keithley 6487 picoammeter as a voltage source and current reader, a membrane voltage of 5V was applied to the transducer and two values ​​were recorded per second. A square wave pulse heating voltage was applied to the resistance wire using a RIGOL DP832A with the following parameters: low voltage 0V, high voltage 6.5V and 50% duty cycle; frequency adjustment range: 0.01Hz. Sensor used: SnO 2 NFs-1, SnO 2 NFs-2, Co 3 O 4 @SnO 2 、NiO@SnO 2 、CuO@SnO 2 、ZnO@SnO 2 Sensor. Specific results are as follows Figure 6 .

[0063] Example 2: Using a Keithley 6487 picoammeter as a voltage source and current reader, a membrane voltage of 5V was applied to the transducer and two values ​​were recorded per second. A square wave pulse heating voltage was applied to the resistance wire using a RIGOL DP832A with the following parameters: low voltage 0V, high voltage 6.5V and 50% duty cycle; frequency adjustment range: 0.02Hz. Sensor used: SnO 2 NFs-1, SnO 2 NFs-2, Co 3 O 4 @SnO 2 、NiO@SnO 2 、CuO@SnO 2 、ZnO@SnO 2 Sensor. Specific results are as follows Figure 7 .

[0064] Example 3: Using a Keithley 6487 picoammeter as a voltage source and current reader, a membrane voltage of 5V was applied to the transducer and two values ​​were recorded per second. A square wave pulse heating voltage was applied to the resistance wire using a RIGOL DP832A with the following parameters: low voltage 0V, high voltage 6.5V and 50% duty cycle; frequency adjustment range: 0.03Hz. Sensor used: SnO 2 NFs-1, SnO 2 NFs-2, Co 3 O 4 @SnO 2 、NiO@SnO 2 、CuO@SnO 2 、ZnO@SnO 2 Sensor. Specific results are as follows Figure 8 .

[0065] Example 4: Using a Keithley 6487 picoammeter as a voltage source and current reader, a membrane voltage of 5V was applied to the transducer and two values ​​were recorded per second. A square wave pulse heating voltage was applied to the resistance wire using a RIGOL DP832A with the following parameters: low voltage 0V, high voltage 6.5V and 50% duty cycle; frequency adjustment range: 0.04Hz. Sensor used: SnO 2 NFs-1, SnO 2 NFs-2, Co 3 O 4 @SnO 2 、NiO@SnO 2 、CuO@SnO 2 、ZnO@SnO 2 Sensor. Specific results are as follows Fig. 9 .

[0066] Example 5: Using a Keithley 6487 picoammeter as a voltage source and current reader, a membrane voltage of 5V was applied to the transducer and two values ​​were recorded per second. A square wave pulse heating voltage was applied to the resistance wire using a RIGOL DP832A with the following parameters: low voltage 0V, high voltage 6.5V and 50% duty cycle; frequency adjustment range: 0.05Hz. Sensor used: SnO 2 NFs-1, SnO 2 NFs-2, Co 3 O 4 @SnO 2 、NiO@SnO 2 、CuO@SnO 2 、ZnO@SnO 2 Sensor. Specific results are as follows Fig.10 .

[0067] (4) Identification of 11 types of VOCs

[0068] The present invention uses six sensors integrated into an array to identify different VOCs. First, the data is preprocessed and the response characteristic curves of different gases are normalized. Then, the linear discriminant analysis (LDA) algorithm is used to reduce the dimension of all data and extract features. At the same time, the K-means algorithm is used to process the reduced-dimensional data. When the frequency modulation is 0.02Hz and the duty cycle is 50%, the six-sensor array is used to successfully identify 11 VOCs, such as Fig.11 In general, the successful identification of multiple VOCs by the present invention helps to better understand their environmental impact, better manage air quality, reduce their impact on health, and effectively control environmental pollution sources.

[0069] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a tin oxide-based nanofiber gas sensor array, characterized in that: include: Material selection: The gas sensor array uses six sensors as components of the array, and the sensors are: SnO2NFs-1, SnO2NFs-2, Co3O4@SnO2, NiO@SnO2, CuO@SnO2, ZnO@SnO2; Substrate selection: Choose six-pin nickel-chromium substrate; Preparation of sensitive film layer: The sensitive material is deposited on the substrate in the form of a thin film. During the preparation process, parameters such as temperature, atmosphere and pressure must be well controlled to ensure the uniformity and consistency of the sensitive film layer. Preparation of polar electrodes: Processing polar electrodes on the sensitive film layer to provide input and output of current and voltage; Packaging protection: Packaging the prepared sensitive components to protect the sensitive film layer from interference from the external environment and impurities; Connection and testing: Connect and fix the sensitive components to the external circuit and perform relevant tests.

2. The method for preparing a tin oxide-based nanofiber gas sensor array according to claim 1, characterized in that: Ceramic sheet is selected as the main structure of the sensor. The sensing element is mainly supported by a six-pin base. The gold electrode on the front of the heating ceramic plate is used as a test electrode, and the RuO2 resistor on the back is used as a heating electrode to provide the required working temperature for the target gas test.

3. The method for preparing a tin oxide-based nanofiber gas sensor array according to claim 1, characterized in that: During the component preparation process, various parameters and conditions need to be strictly controlled to ensure the stability and reliability of sensitive performance; in addition, in order to obtain better sensing performance, the performance of the sensor element can be further improved by regulating factors such as temperature, pressure, atmosphere, etc. during the preparation process, as well as optimizing material and structural design.

4. The method for preparing a tin oxide-based nanofiber gas sensor array according to claim 1, characterized in that: The gas sensor is a MOS gas sensor.

5. The method for preparing a tin oxide-based nanofiber gas sensor array according to claim 1, characterized in that: The preparation of different tin oxide-based nanofiber gas sensors is specifically: pure SnO2NFs-1 nanofibers after thermal oxidation; chain-like SnO2NFs-2 nanofibers after thermal oxidation; (cf) thermally oxidized nanofibers embedded with different adsorbed ions (Co, Ni, Cu, Zn) (Co3O4@SnO2, NiO@SnO2, CuO@SnO2, ZnO@SnO2).

6. The method for preparing a tin oxide-based nanofiber gas sensor array according to claim 1, characterized in that: For the sensors that have been manufactured, they need to be subjected to stable aging treatment, generally by being properly stored in dry conditions for 12-24 hours.

7. A temperature control method for a tin oxide-based nanofiber gas sensor array according to any one of claims 1 to 6, characterized in that: include: The specific method for adjusting the frequency, duty cycle and voltage parameters is as follows: A Keithley 6487 picoammeter was used as a voltage source and current reader to apply a membrane voltage of 5 V to the transducer and record two values ​​per second; A square wave pulse heating voltage was applied to the resistance wire using RIGOL DP832A, and the parameters were as follows: low voltage 0 V, high voltage 6.5 V, and 50% duty cycle; frequency adjustment range: 0.01 Hz-0.05 Hz.

8. The method for preparing a tin oxide-based nanofiber gas sensor array according to any one of claims 1 to 6, characterized in that: Also included are dynamic gas sensing performance tests, including: The sensing measurements were performed in a closed glass container equipped with appropriate gas flow inlet and outlet; the temperature-modulated sensing behavior of the detected gas was performed in dry air, and each measurement was repeated more than three times; The response is defined as S = R at a characteristic temperature point a / R g , where R a and R g are the resistances in dry air and in the presence of the detected gas at the corresponding characteristic temperature points, respectively; Finally, data was collected by computer and the characteristic response curve of the target gas under temperature modulation was obtained; one point that needs to be emphasized is that all gas sensing measurements are carried out in dry air.

9. An application of a tin oxide-based nanofiber gas sensor array according to any one of claims 1 to 6, characterized in that: The tin oxide-based nanofiber gas sensor array is applied to the identification of 11 VOCs gases. The VOCs gas identification method is: Use linear discriminant analysis; combined with K-means algorithm; Quantitative analysis is used to identify and analyze gases.

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