Catalytic combustion hydrogen sensor for realizing self-calibration by utilizing pulse heating and preparation method of catalytic combustion hydrogen sensor

Abstract

The invention discloses a catalytic combustion type hydrogen sensor capable of realizing self-calibration based on pulse heating and a preparation method of the catalytic combustion type hydrogen sensor. The sensor comprises a mica sheet substrate, a platinum resistor, an aluminum oxide insulating layer, a palladium nanoparticle catalytic layer, a pulse driving unit and a data processing module. According to the sensor, through periodic multi-stage pulse excitation, a reference model between resistance increment and voltage is firstly constructed by two low-voltage pulses, then catalytic combustion reaction is excited by high-voltage pulses, actual resistance is collected, hydrogen response signals are extracted in a differential mode, and quantitative measurement of hydrogen concentration is achieved in combination with a calibration curve. The platinum resistor has a good linear thermal response characteristic, power consumption is remarkably reduced through a pulse driving mode, and high-precision hydrogen detection without a compensation element is achieved. The method has the advantages of simple structure, low power consumption, high sensitivity, strong environmental adaptability and the like, and is suitable for hydrogen leakage monitoring in a complex industrial or energy environment.

Description

Technical Field

[0001] This invention relates to the field of gas sensor technology, and in particular to a hydrogen sensor based on catalytic combustion mechanism, combined with pulse heating drive and differential self-calibration mechanism, and its preparation method. Background Technology

[0002] With the widespread application of hydrogen energy in the energy, transportation, and industrial sectors, the importance of hydrogen leak monitoring is becoming increasingly prominent. Hydrogen is a colorless, odorless, flammable, and explosive gas that cannot be detected by conventional senses. Therefore, there is an urgent need for hydrogen detection technologies with high sensitivity, high reliability, and low power consumption to provide safety assurance.

[0003] Currently, catalytic combustion hydrogen sensors have unique advantages in high-concentration hydrogen detection due to their wide response range and good stability. However, traditional catalytic combustion sensors mostly use filament heating structures, which suffer from mechanical fragility, high power consumption, and severe drift, making them unsuitable for vibration or dynamic operating conditions. To address this, existing research has proposed a planar catalytic combustion hydrogen sensor with a mica substrate. A three-layer structure of platinum resistance thermometer, alumina, and palladium catalytic layer is constructed using magnetron sputtering and cluster deposition methods, achieving structural stability and enhanced response (see authorized patent ZL202111621009.0).

[0004] Although the aforementioned planar sensor structure solves the fragility of filament structures and simplifies the complex fabrication of MEMS devices, it still relies on constant voltage or DC heating to drive the sensing, and the following key technical bottlenecks remain unresolved:

[0005] 1. Power consumption issue: Continuous power supply in DC heating mode results in high energy consumption, making it difficult to apply to low-power or portable terminals.

[0006] 2. Signal drift problem: Joule heating during continuous heating causes baseline resistance drift, which interferes with the hydrogen response signal, requiring additional compensation components.

[0007] 3. Issues with detection accuracy: It cannot effectively distinguish between temperature rise caused by catalytic reaction and changes in resistance caused by ambient temperature fluctuations and electrothermal non-uniformity.

[0008] To address the aforementioned issues, this invention proposes a catalytic combustion hydrogen sensor based on pulse heating control and differential resistance analysis. This sensor not only maintains the high robustness and low heat capacity advantages of the mica support structure but also reduces power consumption through periodic pulse drive and introduces a self-calibration mechanism to solve baseline drift problems, significantly improving the sensor's stability, accuracy, and application flexibility. This method differs fundamentally from existing patented technologies in its sensing principle, driving method, and signal processing mechanism, demonstrating significant technological advancement and promising prospects for industrial transformation. Summary of the Invention

[0009] This invention aims to overcome the shortcomings of existing catalytic combustion hydrogen sensors, such as high power consumption, temperature drift interference, and complex structure, and provides a catalytic combustion hydrogen sensor based on pulse heating and a self-calibration mechanism, as well as its preparation method. This sensor has a compact structure, clear testing logic, and features low power consumption, high response, high stability, and automatic calibration capability without compensation components, making it suitable for quantitative hydrogen detection in complex environments.

[0010] To achieve the above objectives, this invention employs a detection strategy driven by periodic pulse heating and combines it with a differential linear extrapolation calibration mechanism to construct a signal extraction method.

[0011] A catalytic combustion hydrogen sensor that utilizes pulse heating for self-calibration includes,

[0012] Mica sheet substrate is used to support the entire sensing structure;

[0013] A platinum resistance thermometer, disposed on the substrate, is used for heating and as a temperature-sensitive element;

[0014] An aluminum oxide film covers the platinum resistance and serves as an insulating layer to isolate it from external gases.

[0015] A palladium nanoparticle catalytic layer is attached to the surface of the alumina film and is used to catalyze the flameless combustion reaction of hydrogen and oxygen.

[0016] A pulse driving unit is used to periodically apply multiple pulse sequences with different voltage amplitudes to the platinum resistance, so that the platinum resistance generates different resistance response signals under different voltages and the presence or absence of hydrogen gas.

[0017] The data acquisition and processing module is used to acquire and process resistance signals under different conditions, and construct a calibration curve between the resistance difference and hydrogen concentration under conditions of presence and absence of hydrogen, so as to realize the quantitative detection of hydrogen concentration.

[0018] Furthermore, the platinum resistance thermometer has a positive temperature coefficient, with a temperature resistivity α of (0.00374 ± 0.0005) °C. -1 The resistance value has an approximately linear relationship with temperature, and its initial resistance value is controlled between 4 and 12Ω at room temperature.

[0019] Furthermore, the mica substrate has a thickness of 10–50 micrometers, the alumina film has a thickness of 0.3–1.0 micrometers, and the palladium nanoparticles have a particle size of 1–20 nm.

[0020] The method for detecting hydrogen concentration using a catalytic combustion hydrogen sensor consists of three stages within a single measurement cycle:

[0021] 1. Duty cycle reference stage: Apply a low voltage V0 (e.g., 0.05-0.1V). At this time, the temperature of the platinum resistance is close to the ambient temperature, and hydrogen cannot undergo catalytic combustion. The measured resistance value R0 can be used as the environmental baseline.

[0022] 2. Linear Modeling Stage: Two small-amplitude voltage pulses V1 and V2 (within the range of 0.2–0.3V) are applied sequentially, and the resistances R1 and R2 are obtained respectively. Their relative changes ΔR1 = R1 – R0 and ΔR2 = R2 – R0 are calculated. In the modeling stage of this invention, the resistance changes ΔR1 and ΔR2 corresponding to the two small-amplitude voltage pulses do not strictly follow a linear relationship, but rather exhibit the following power-law characteristics as found through experimental fitting:

[0023] ΔR = a(V - V0) γ

[0024] Where a is a constant and γ is a power exponent, which is approximately 1.2 in actual measurements. This relationship reflects the nonlinear heating behavior caused by a combination of factors such as Joule heating, temperature coefficient of resistance, and interfacial heat conduction during actual heating.

[0025] It is important to emphasize that, at this stage, the temperature rise corresponding to the two small-amplitude pulsed voltages applied is far below the activation temperature required for the hydrogen catalytic reaction to occur on the palladium catalyst surface (typically around 150–200 °C). Therefore, even in the presence of hydrogen gas, no catalytic combustion reaction will occur at these two voltage points. The measured resistance changes are entirely attributable to the electrothermal effect and do not include the contribution of the heat of hydrogen reaction.

[0026] 3. High-voltage response stage:

[0027] A high-voltage pulse V3 (e.g., 0.5–1.0V) is applied, and the actual resistance value R under a certain hydrogen concentration is measured. meas After fitting parameters a and γ to ΔR1 and ΔR2 with V1 and V2, the theoretical resistance value in a hydrogen-free environment under high voltage can be extrapolated.

[0028] R th =R0+a(V3-V0) γ

[0029] Then, the differential resistance response caused by hydrogen gas is calculated:

[0030] ΔR gas =R meas –R th

[0031] This difference represents the additional resistance increase caused by the heat released during the catalytic combustion of hydrogen. Experiments have shown that ΔR gasThe sensor exhibits a stable, approximately linear relationship with hydrogen concentration. Therefore, it not only enables rapid detection of hydrogen leaks but also possesses excellent quantitative measurement capabilities, making it suitable for high-precision hydrogen monitoring scenarios.

[0032] Unlike traditional DC heating or MEMS reference element compensation methods, this invention achieves self-calibration of drift within the structure using a linear model fitted by two low-amplitude pulses. Due to the use of intermittent pulse excitation, the average power consumption per unit time is significantly reduced, making it suitable for deployment in mobile terminals, embedded nodes, or wireless sensing systems.

[0033] To further improve device consistency and model stability, this invention limits the initial resistance of the platinum resistance thermometer to the range of 4–12 Ω during fabrication. Four to six platinum resistance electrodes at different locations are selected and placed in an oven. Their resistances are measured using a multimeter at ambient temperatures (room temperature, 50°C, 70°C, and 100°C). Based on the calculation of the temperature resistivity α = (R2–R1) / R1 × 1 / (T2–T1), where R1 and R2 are the resistance values ​​at temperatures T1 and T2 respectively, the temperature resistivity α is selected to be close to 0.00374°C. -1 The samples are used to ensure the linear predictability of the thermal response curve and the model's generality across samples.

[0034] Furthermore, the sensor described in this invention does not contain a compensation resistor element, and relies on the difference calculation between the internal measured value and the linear prediction model to perform zero-point self-calibration.

[0035] The method for preparing the catalytic combustion hydrogen sensor of the present invention includes the following steps:

[0036] a) Provide a mica sheet substrate with a thickness of 10 to 50 micrometers, clean and dry it in sequence, and treat it with oxygen plasma to enhance the adhesion of the film layer;

[0037] b) Platinum resistance patterns were prepared on the surface of the substrate by physical vapor deposition, and the structural morphology was defined by a metal mask to control the initial resistance between 4 and 12 ohms.

[0038] c) Deposit an aluminum oxide film with a thickness of 0.3 to 1 micrometer on the surface of the platinum resistance thermometer to form an insulating protective layer. The deposition is preferably completed by magnetron sputtering.

[0039] d) Using cluster beam deposition technology, palladium nanoparticles with a particle size of 1 to 20 nanometers are deposited on the surface of alumina thin films to form a catalytically active layer.

[0040] In summary, the key innovations of this invention include:

[0041] 1. Differential modeling self-calibration mechanism: No reference element is required; automatic zero-point correction is achieved through an internal linear model.

[0042] 2. Pulse segmented test logic: compact structure, clear temperature control, and high test repeatability;

[0043] 3. Power consumption optimization: Pulse excitation significantly reduces operating energy consumption;

[0044] 4. Linear quantification capability: ΔR gas It is approximately linear with hydrogen concentration, supporting engineering calibration and concentration regression;

[0045] 5. High adaptability: The system has high stability and is suitable for rapid response and high-reliability monitoring of hydrogen leaks in complex environments.

[0046] The sensor of this invention not only differs substantially from the authorized patent (ZL202111621009.0) at the structural level, but also achieves essential technological advancements in driving method, detection mechanism, and calibration capability, possessing significant novelty, inventiveness, and practicality. This invention is applicable to various hydrogen-related application scenarios such as hydrogen safety detection, storage and transportation monitoring, fuel cell stack protection, and industrial alarms, and has broad promotion and industrialization value. Attached Figure Description

[0047] Figure 1 : Schematic diagram of the hydrogen sensor structure and control module composition of this invention;

[0048] Figure 1 In the diagram, 101 is a mica sheet, 102 is a platinum resistance thermometer, 103 is an alumina film, 104 is a palladium nanoparticle catalytic layer, 105 is a pulse drive unit, and 106 is a data acquisition and processing module.

[0049] Figure 2 The following is a diagram showing the pulse period voltage loading timing and the corresponding resistance change trend in the embodiment.

[0050] Figure 3 : This refers to the resistance change (ΔR) obtained under hydrogen-free conditions and by extrapolating the theoretical resistance value under high voltage from two small-amplitude voltage pulses, as a function of the 1.2 power of the pulse voltage amplitude (ΔV). 1.2 Relationship diagram;

[0051] Figure 4 : This represents the change in resistance as a function of the pulse voltage amplitude to the power of 1.2 (ΔV) under conditions of no hydrogen and 10,000 ppm hydrogen concentration in the examples. 1.2 (Change graph)

[0052] Figure 5 : ΔR represents the change in resistance (ΔR) obtained by the catalytic combustion effect of pure hydrogen under the same pulse voltage according to this invention. gas The relationship between hydrogen concentration and hydrogen concentration. Detailed Implementation

[0053] like Figure 1 As shown, this invention provides a self-calibrating catalytic combustion hydrogen sensor structure based on pulse heating. The device uses a mica sheet 101 as a substrate, a platinum resistance thermometer 102, an alumina thin film 103, a palladium nanoparticle catalytic layer 104, and an external control and processing module, including a pulse driving unit 105 and a data acquisition and processing module 106.

[0054] 1. Structure preparation steps:

[0055] (1) Substrate treatment: Select mica sheets with a thickness of 0.025mm, clean and dry them by ultrasonication, and then place them in a plasma cleaning machine for surface treatment. In an oxygen atmosphere of 800Pa, use a radio frequency power supply to generate plasma with a radio frequency power of 70W for 15 minutes to make the surface of the mica sheets hydrophilic.

[0056] (2) Resistance layer deposition: A 10 nm titanium adhesion layer was first deposited by magnetron sputtering, followed by a platinum resistance pattern of about 600 nm (mask patterning). The platinum resistance was prepared by magnetron sputtering equipment with a DC power supply and a sputtering power of about 30 W. A device sample with a temperature resistivity α of 0.00374℃-1 and an initial resistance of 5.97Ω was obtained.

[0057] (3) Insulating layer deposition: The alumina thin film was prepared by magnetron sputtering. The sputtering power source was an RF power source, and the target material was Al2O3. The argon gas pressure in the sputtering chamber was maintained at about 1 Pa, and the film thickness was controlled at about 470 nm. The alumina thin film covered the platinum resistance thermometer and served as an insulating layer to isolate it from external gases.

[0058] (4) Catalyst layer deposition: Palladium nanoparticles were prepared using a cluster beam deposition apparatus. Palladium nanoparticles with a particle size of 5–10 nm were deposited using cluster beam deposition technology. Both the sputtering gas and the buffer gas were argon, with flow rates of 60 sccm and 70 sccm respectively introduced into the cavity. The sputtering power was approximately 8 W, and the deposition rate was… The deposition time was 3000 s. For details, please refer to DOI: 10.1002 / sstr.202400549.

[0059] 2. Pulse-driven measurement process

[0060] Figure 2 The resistance change curve of the Pt resistor under a pulse voltage is shown. Figure 2 As shown, the sensor executes the following periodic voltage sequence (total period 70s) through the pulse drive unit:

[0061] Phase 1: Reference segment (0-10s): Apply 0.1V and measure the resistance R0 = 5.9771Ω. At this time, the temperature rise is slight and the Pt resistance is approximately at ambient temperature.

[0062] Phase 2: Modeling (30s): Two low-amplitude pulses, 0.2V and 0.3V, are applied sequentially, and the corresponding resistances R1 = 6.1677Ω and R2 = 6.2961Ω are recorded. ΔR1 = R1 – R0 and ΔR2 = R2 – R0 are calculated respectively. Since the temperature rise caused by these two low voltages is much lower than the ignition temperature (~70℃) of palladium or platinum catalysts, no catalytic combustion reaction will occur even if hydrogen is present in the environment. Therefore, the resistance change is solely due to thermal effects.

[0063] Phase 3: Response phase (50–60 s): Apply a high-amplitude pulse of 0.8 V and measure the actual resistance value R. meas In the presence of hydrogen, this stage will trigger a catalytic combustion reaction, causing additional temperature rise and resistance change.

[0064] Stages 1 to 3 described above each constitute one pulse cycle. Within each pulse cycle, the pulse heating time is half of the cycle, and there are three intervals of heating processes within one pulse cycle.

[0065] Phase 4: Cooling Section (60–70 s): The heating voltage is turned off, and the device cools and stabilizes under natural conditions. Based on experimental observations, the resistance change ΔR is approximately linearly related to the 1.2 power of the pulse voltage amplitude, and the following model can be established:

[0066] ΔR = a(V – 0.1) 1.2

[0067] The coefficient a is 2.4815, fitted from the ΔR values ​​corresponding to two low-voltage pulses (0.2V and 0.3V). This leads to the extrapolation of the theoretical resistance R that the high-voltage pulse (0.8V) should have in the absence of hydrogen. th :

[0068] R th =R0 + 2.4815 × (0.8 - 0.1) 1.2 = 7.5946 (actually measured as 7.5778 Ω)

[0069] The change in resistance induced by hydrogen is then extracted using differential extraction:

[0070] ΔR gas =R meas –R th .

[0071] 3. Data processing module and concentration quantification

[0072] ①The data processing module performs the following functions:

[0073] ②Record the pulse voltage and corresponding resistance value in real time;

[0074] ③ Fitting ΔR–ΔV 1.2 The model fits the pure thermal response coefficient α;

[0075] ④ Extrapolated theoretical resistance R th The differential response ΔR caused by hydrogen extraction gas ;

[0076] Hydrogen concentration back-calculation based on a preset calibration curve:

[0077] C H2 =bΔR gas

[0078] Where b is the fitting parameter obtained in advance through multiple concentration calibration experiments.

[0079] 4. Response Verification and Linearity Properties

[0080] like Figure 3 As shown, under the condition of only background gas (no hydrogen), two low-amplitude pulse voltages of 0.2V and 0.3V and a high-amplitude pulse voltage of 0.8V are set. For each ΔR, the values ​​of ΔR and ΔV are calculated, and the results are fitted. 1.2 The linear relationship was analyzed, and the actual linear fitting slope was found to be 2.4198, which is the linear fitting slope under the three voltage conditions of 0.2V, 0.3V and 0.8V, and the condition without hydrogen. After processing the two low-amplitude pulses in the same way, the theoretical resistance value under high voltage was extrapolated, and its linear fitting slope α was 2.4819. By comparing the two slopes, it can be found that the results are in good agreement.

[0081] like Figure 4 As shown in the figure, under the same test conditions, without hydrogen gas, the change in resistance is entirely determined by the amplitude of the pulse voltage (i.e., ΔV = V – V0). The relationship between ΔR and ΔV can be seen in the figure. 1.2 A good linear relationship is formed; however, the change in resistance after hydrogen gas is introduced depends not only on the pulse voltage but also on the concentration of hydrogen gas introduced, i.e., ΔR = ΔR V +ΔR gas Furthermore, the ΔR produced by the catalytic combustion reaction of pure hydrogen can be calculated. gas Taking a hydrogen gas concentration of 10,000 ppm as an example, from... Figure 4It can be seen that under the two low-amplitude pulses of 0.2V and 0.3V, due to the low temperature, the temperature rise caused by these two low voltages is far below the ignition temperature of the catalyst. Even if hydrogen is present in the environment, no catalytic combustion reaction will occur. The collected resistance change is entirely attributed to the electrothermal effect and does not include the contribution of the heat of hydrogen reaction. Under the high-amplitude pulse voltage, hydrogen undergoes catalytic combustion, resulting in a higher temperature rise and thus a larger resistance change. Below 0.3V, the introduced hydrogen does not undergo catalytic combustion. At this point, the points at the two low-amplitude pulse voltages and the point where no hydrogen is present almost coincide. At 0.8V, the temperature reaches the ignition temperature of the catalyst, and catalytic combustion occurs on the catalyst surface. ΔR can be calculated, and the resistance value ΔR at high voltage can be obtained by extrapolation. V The difference between the two is the additional resistance increase caused by the heat released from the catalytic combustion of hydrogen.

[0082] Hydrogen gas was introduced in the concentration range of 500–10000 ppm, and the experimental results are as follows: Figure 5 As shown, ΔR gas The hydrogen concentration showed a linear increasing trend, and the goodness of fit R 2 The resistance value exceeds 0.99. When the voltage is less than 0.3V, the resistance change does not change with the hydrogen concentration, indicating that the catalytic reaction is not initiated in the low voltage range; when the voltage is greater than 0.8V, the catalytic reaction begins, and the resistance response rises rapidly, proving that the differential model extraction is effective.

[0083] 5. Power Consumption Comparison

[0084] For comparison, let's take a 0.8V load as an example:

[0085] (1) DC mode: 100s constant voltage loading, power P = 0.084W, total energy consumption E = 8.4J;

[0086] (2) Pulse mode: period 20s, pulse width 10s, total energy consumption E = 4.2J in 5 cycles;

[0087] Pulse heating reduces actual energy consumption by more than 50% compared to DC heating.

Claims

1. A catalytic combustion hydrogen sensor that utilizes pulse heating for self-calibration, characterized in that, include, Mica sheet substrate is used to support the entire sensing structure; A platinum resistance thermometer, disposed on the substrate, is used for heating and as a temperature-sensitive element; An aluminum oxide film covers the platinum resistance and serves as an insulating layer to isolate it from external gases. A palladium nanoparticle catalytic layer is attached to the surface of the alumina film and is used to catalyze the flameless combustion reaction of hydrogen and oxygen. A pulse driving unit is used to periodically apply multiple pulse sequences with different voltage amplitudes to the platinum resistance, so that the platinum resistance generates different resistance response signals under different voltages and the presence or absence of hydrogen gas. The data acquisition and processing module is used to establish a thermal response model based on the resistance change under low-amplitude pulses and extract the hydrogen response signal through the resistance difference under high-amplitude pulses, thereby realizing the quantitative detection of hydrogen concentration.

2. The catalytic combustion hydrogen sensor for self-calibration using pulse heating as described in claim 1, characterized in that, The platinum resistance thermometer has a positive temperature coefficient, with a temperature resistivity α of (0.00374 ± 0.0005) °C. -1 The resistance value has an approximately linear relationship with temperature, and its initial resistance value is controlled between 4 and 12Ω at room temperature.

3. A catalytic combustion hydrogen sensor for self-calibration using pulse heating as described in claim 1, characterized in that, The mica substrate has a thickness of 10–50 micrometers, the alumina film has a thickness of 0.3–1.0 micrometers, and the palladium nanoparticles have a particle size of 1–20 nm.

4. A catalytic combustion hydrogen sensor for self-calibration using pulse heating as described in claim 1, characterized in that, The working process of the pulse drive unit and the data acquisition and processing module includes: I. The process of applying voltage to the platinum resistance thermometer by the pulse drive unit S1. Apply an extremely low voltage V0 during the duty cycle phase to acquire the ambient reference resistance R0 at this voltage. S2. Apply at least two low-amplitude pulse voltages V1 and V2 to model the pure thermal response; S3. Apply at least one high-amplitude pulse voltage V3 to initiate catalytic combustion and collect the response resistance value; II. Data Acquisition and Processing Module: The process of data acquisition and processing. M1. Collect the environmental reference resistance R0 under extremely low voltage V0, and collect the resistances R1 and R2 under two low amplitude pulse voltages V1 and V2, and calculate the corresponding resistance changes ΔR1=R1-R0, ΔR2=R2-R0. M2. Construct a linear prediction model, the formula of which is a power function: ΔR=a(V-V0) γ a is a constant, and γ is a power exponent; Substituting the low-amplitude pulse voltage and the corresponding resistance change in step M1 into the power function above, we can obtain the values ​​of the constant a and the power exponent γ. M3. Calculate the theoretical resistance value in a hydrogen-free environment under a higher amplitude pulse voltage V3 using the power function from step M2: R th =R0+a(V3-V0) γ Collect a high-amplitude pulse voltage V3 and the actual resistance value R under a certain hydrogen concentration. meas Calculate the differential resistance response ΔR caused by hydrogen gas. gas =R meas -R th To extract the response signal caused by hydrogen combustion; M4, based on ΔR gas By using the calibration function relationship between hydrogen concentration and the ambient hydrogen concentration, the current ambient hydrogen concentration can be deduced, thus achieving quantitative detection.

5. A catalytic combustion hydrogen sensor for self-calibration using pulse heating as described in claim 4, characterized in that, The extremely low voltage V0 is 0.05 to 0.1V.

6. A catalytic combustion hydrogen sensor for self-calibration using pulse heating as described in claim 4, characterized in that, The lower amplitude pulse voltages V1 and V2 are both in the range of 0.2 to 0.3V.

7. A catalytic combustion hydrogen sensor for self-calibration using pulse heating as described in claim 4, characterized in that, The higher amplitude pulse voltage V3 is 0.5 to 1.0 V.

8. A catalytic combustion hydrogen sensor for self-calibration using pulse heating as described in claim 4, characterized in that, The pulse period of the pulse drive unit is set to 3 to 30 seconds, and the pulse heating time is half of the period.

9. The method for preparing a self-calibrating catalytic combustion hydrogen sensor using pulse heating as described in claim 1, characterized in that, Includes the following steps: a) Provide a mica sheet substrate with a thickness of 10 to 50 micrometers, clean and dry it in sequence, and treat it with oxygen plasma to enhance the adhesion of the film layer; b) Platinum resistance patterns were prepared on the surface of the substrate by physical vapor deposition, and the structural morphology was defined by a metal mask to control the initial resistance between 4 and 12 ohms. c) Deposit an aluminum oxide film with a thickness of 0.3 to 1 micrometer on the surface of the platinum resistance thermometer to form an insulating protective layer. The deposition is preferably completed by magnetron sputtering. d) Using cluster beam deposition technology, palladium nanoparticles with a particle size of 1 to 20 nanometers are deposited on the surface of alumina thin films to form a catalytically active layer.

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