Manufacturing method for catalytic combustion type hydrogen sensor with high response sensitivity based on porous alumina support
A catalytic combustion hydrogen sensor using a porous alumina support with a platinum resistor and palladium nanoparticles addresses high cost and sensitivity issues, providing stable and sensitive hydrogen detection in vehicles.
Patent Information
- Application Number
- JP2023117303
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2023-05-23
- Filing Date
- 2023-07-19
- Publication Date
- 2024-12-16
- Estimated Expiration
- 2043-07-19
AI Technical Summary
Conventional catalytic combustion hydrogen sensors face issues such as high cost, complex fabrication processes, low sensitivity, and susceptibility to mechanical vibrations leading to device failure.
A catalytic combustion hydrogen sensor utilizing a porous alumina support with a platinum resistor and palladium nanoparticles deposited on its pore side, which distributes heat generated during flameless combustion, enhancing sensitivity and stability.
The sensor achieves high sensitivity and stability, reducing costs and avoiding heat loss, making it suitable for in-vehicle applications with frequent mechanical vibrations.
Smart Images
Figure 2024174280000001_ABST
Abstract
Description
[Technical field]
[0001] The present invention relates to the technical field of gas sensors, and more particularly to a catalytic combustion type hydrogen sensor with high response sensitivity based on a porous alumina support and a method for manufacturing the same. [Background technology]
[0002] Hydrogen energy is known as an ideal renewable energy, and promoting the development of hydrogen energy and related industries has become an important strategic direction for environmental governance and energy utilization. However, hydrogen has a fast diffusion rate and is very prone to leak during production, transportation and use. If the volume percentage of the leaked concentration in the air is 4-75%, it will explode violently when it encounters a flame. In addition, hydrogen is colorless and odorless, making it difficult for the human five senses to detect. Therefore, developing a hydrogen sensor with high sensitivity, fast response speed, and safety and reliability is very important for the safe production and application of hydrogen.
[0003] As a kind of new energy vehicle, hydrogen fuel cell vehicles have attracted attention in the field of hydrogen energy due to their characteristics of zero pollution and zero emissions. Ensuring the safety of hydrogen for fuel cells is the foundation for promoting the development of hydrogen fuel cell vehicles. In the field of fuel cell vehicles, on-board hydrogen sensors have very high requirements for the stability of product performance. Catalytic combustion hydrogen sensors have an automatic compensation function, which can largely eliminate the drift of the device itself and the influence of changes in temperature and humidity in the environment, thereby meeting the practical needs of high stability in the on-board field. However, most traditional catalytic combustion hydrogen sensors use a filament structure, and frequent on-board vibrations can cause the filament to break and the device to fail, which greatly limits its popularity in the on-board field. With the advancement of micro-nano processing technology, catalytic combustion hydrogen sensors based on microelectromechanical systems (MEMS) have appeared, which can effectively solve the defect that the filament structure is prone to breakage, but the fabrication cost is high and the process is complicated (Catalytic combustion gas sensor based on MEMS technology [J]. Modern Information Science and Technology, 2018,2(10):179-181). In addition, the planar MEMS catalytic combustion gas sensor has the problem of being prone to heat loss during operation, that is, the heat generated by local catalytic combustion in the planar structure tends to be lost to the ambient temperature. Therefore, the temperature change of the platinum resistor is very limited, so the sensitivity of the device is low, and compared with the filament-structured catalytic combustion gas sensor, the sensitivity of the MEMS catalytic combustion gas sensor based on the planar structure shows no advantage, which is another disadvantage of the MEMS catalytic combustion gas sensor. Based on this, developing a catalytic combustion hydrogen sensor with low cost and high performance is currently a problem that needs to be solved. Summary of the Invention [Problem to be solved by the invention]
[0004] The present invention aims to overcome the problems of conventional filament catalytic combustion hydrogen sensors, such as their proneness to breakage and short service life, and the complex process, high cost, and low sensitivity of MEMS catalytic combustion hydrogen sensors, and to provide a new type of catalytic combustion hydrogen sensor based on a porous alumina support and its manufacturing method. The catalytic combustion hydrogen sensor of the present invention has the advantages of low cost, high performance, etc. [Means for solving the problem]
[0005] In order to achieve the above object, the present invention proposes a catalytic combustion type hydrogen sensor device based on a porous alumina support. The catalytic combustion element adopts the bottom surface of a porous alumina sheet as a substrate, and uses a mask to combine with physical vapor deposition to manufacture a platinum resistor and an alumina thin film, and uses cluster beam deposition to deposit palladium nanoparticles on the pore side of the porous alumina sheet. When the catalytic combustion element is working, hydrogen is flamelessly burned by the catalytic action of palladium nanoparticles, releasing a large amount of heat, which affects the temperature of the porous alumina sheet, and the resistance value of the platinum resistor increases with the increase of temperature, and the change of the platinum resistor is monitored to realize the quantitative detection of hydrogen concentration. Compared with the conventional MEMS catalytic combustion gas sensor and the filament type catalytic combustion gas sensor, the sensor of the present invention mainly has the following advantages: 1. Avoid the disadvantages of the conventional MEMS catalytic combustion gas sensor, which is expensive and complicated in process. 2. Provides excellent performance, such as high stability and reusability, without the defect of filament structure being easily broken. 3. Improves the sensitivity of the device and reduces the operating temperature of the device. The structure based on the porous alumina support provides an excellent carrier for the catalyst, and the heat generated by the palladium nanoparticles inside the pores is distributed in an axial structure throughout the pores, forming an effect similar to that of a heat pipe, which can largely avoid the heat loss during flameless combustion, thereby generating a large temperature change, greatly improving the sensitivity of the device and reducing the initial operating temperature of the device.
[0006] The innovation of the present invention is to design a catalytic combustion hydrogen sensor using a porous alumina support with excellent performance at low operating temperature. A porous alumina sheet is used as a support substrate for platinum resistors and catalysts, and a planar platinum resistor is used as the main element of catalytic combustion. The planar structure of this catalytic combustion hydrogen sensor can effectively avoid the drawback of the floating platinum resistor being easily broken and broken due to frequent vibration in vehicle-mounted gas sensors. In addition, the catalytic combustion hydrogen sensor based on the porous alumina support selects a single-pass alumina sheet to support the platinum resistor and carry the palladium catalyst, and its manufacturing process avoids the complicated MEMS process, reducing the cost of the device. More importantly, the high-response and high-sensitivity catalytic combustion hydrogen sensor based on the porous alumina support of the present invention can distribute the heat generated during flameless combustion of the catalyst and hydrogen throughout the entire pores by depositing the catalyst on the pore side of the porous alumina sheet, thereby reducing heat loss and improving the sensitivity of the sensor.
[0007] In the high-response sensitivity catalytic combustion hydrogen sensor based on the porous alumina support, the porous alumina sheet has a single-path structure, i.e., one side of the sheet has micro-nanoscale pores distributed thereon, and the other side is a pore-free flat surface, which is defined as the bottom surface of the porous alumina sheet. The catalytic combustion element uses the bottom surface of the porous alumina sheet as a substrate, and a platinum resistor and an alumina thin film are attached to the substrate in order, the pore side of the porous alumina sheet is the catalyst carrier region, and the catalyst material is attached to the pore side of the porous alumina sheet, and quantitative detection of hydrogen concentration is realized by monitoring the change in the platinum resistor.
[0008] Preferably, the substrate of the catalytic combustion hydrogen sensor is the bottom surface of a porous alumina sheet. The thickness of the bottom surface of the porous alumina sheet must be sufficient to effectively support the catalytic combustion-based element, and the thickness of the porous alumina sheet may be in the range of 10 to 200 μm.
[0009] Preferably, the catalyst carrier region of the catalytic combustion hydrogen sensor is selected from the pore side of the porous alumina sheet, and the depth of the porous channel needs to ensure that the heat during catalytic combustion can be effectively transferred to the platinum resistor of the catalyst-based element, and the pore depth of the porous alumina sheet can be in the range of 5 to 180 μm.
[0010] Preferably, the catalyst carrier region of the catalytic combustion hydrogen sensor is selected on the pore side of the porous alumina sheet. The diameter of the pores of the porous alumina sheet must meet the requirement that the catalyst can be deposited inside the pores to ensure heat storage in the catalytic combustion process, and the diameter of the pores of the porous alumina sheet can be in the range of 50 to 400 nm.
[0011] Preferably, the catalyst carrier region of the catalytic combustion hydrogen sensor is located on the pore side of the porous alumina sheet. The pore pitch of the porous alumina sheet must ensure heat transfer between the pores, and the pore pitch of the porous alumina sheet may be in the range of 65 to 500 nm.
[0012] Preferably, the platinum resistor of the catalytic combustion-based element is manufactured by electron beam evaporation. The planar platinum resistor can be effectively supported by the substrate, which avoids the problem that the floating platinum resistor in the conventional catalytic combustion sensor is easily broken and causes the device to fail.
[0013] Preferably, the pattern of the platinum resistor can be realized by a metal mask, the thickness of the platinum resistor is controlled to 0.5-10 μm, and the electrode gap of the platinum resistor is controlled to 0.05-5 mm. The platinum resistor manufacturing process avoids the disadvantages of the complicated and high cost of the semiconductor lithography process, and can realize mass production.
[0014] Preferably, in order to ensure that the planar platinum resistor is better attached to the bottom surface of the porous alumina sheet, the substrate is heated to 50-300°C during deposition, and a titanium or chromium thin film having a thickness of 1-10 nm is deposited on the surface of the substrate as an adhesive layer.
[0015] Preferably, the alumina thin film of the catalyst-based element is manufactured by magnetron sputtering. By performing regionalized selective coating using a mask, the alumina thin film covers only the surface of the platinum resistor, and the thickness of the alumina thin film is controlled in the range of 1 to 10 μm.
[0016] Preferably, catalytic palladium nanoparticles required for catalytic combustion elements are manufactured by adopting cluster beam deposition method. The particle size is controlled to 1-100 nm and adhered to the pore side of the porous alumina sheet. Palladium nanoparticles are adhered to both the surface and the inside of the pores of the porous alumina sheet.
[0017] A method for producing a catalytic combustion type hydrogen sensor having high response sensitivity based on the porous alumina support includes the steps of: Step 1) firstly, metal titanium or chromium is deposited as an adhesive layer on the bottom surface of the porous alumina sheet using electron beam evaporation method, then platinum resistor is further deposited using the same method, and its pattern can be realized with a metal mask; Step 2) after depositing the platinum resistor, a layer of alumina thin film is produced on the surface of the platinum resistor by magnetron sputtering to uniformly coat the surface of the platinum resistor, and the platinum resistor is not exposed to environmental gas; Step 3) of producing a catalytic combustion element based on a porous alumina sheet according to the method of steps 1)-2); and 4) depositing palladium nanoparticles on the pore side of the porous alumina sheet using cluster beam techniques, so that the palladium nanoparticles are attached both to the surface of the sheet and inside the pores.
[0018] Furthermore, in step 1), the thickness of the titanium or chromium adhesion layer is 1-10 nm; and in step 1), the platinum resistor is deposited by adopting electron beam evaporation, and the power is 10-100 W.
[0019] Furthermore, in step 2), the thickness of the alumina thin film is 1-10 μm, and in step 2), the alumina thin film is deposited using a magnetron sputtering coating equipment whose sputtering power supply is an RF power supply, the target is an alumina target, the sputtering power is 100-200 W, and the argon pressure in the sputtering chamber is maintained at 0.3-2 Pa.
[0020] Furthermore, in step 3), a cluster beam machine is employed to deposit palladium nanoparticles on the pore side of the porous alumina sheet, the sputtering gas and buffer gas are both argon, the flow rates of the sputtering gas and buffer gas are 60-70 sccm and 70-80 sccm, respectively, the sputtering power is 5-30 W, and the sputtering time is 3500-4500 s. Effect of the Invention
[0021] Compared with the prior art, the beneficial effects of the present invention are as follows:
[0022] 1) This invention proposes a highly responsive and sensitive catalytic combustion hydrogen sensor based on a porous alumina support, in which the bottom surface of a porous alumina sheet is selected as the substrate, and a platinum resistor and an alumina thin film are deposited on the bottom surface of the porous alumina sheet by physical vapor deposition. The manufactured catalytic combustion hydrogen sensor based on a porous alumina support has a planar structure, can operate stably in an in-vehicle environment with frequent mechanical vibrations, and is widely used in in-vehicle hydrogen combustion batteries.
[0023] 2) The present invention deposits a catalyst on the pore side of the porous alumina sheet, so that when the catalyst reacts with hydrogen molecules, the presence of the pores can avoid heat loss during catalytic combustion, greatly improving the sensitivity of the device. In particular, in the catalytic combustion hydrogen sensor of the present invention, the porous alumina sheet used in the catalytic combustion main element is simple to process and has stable structural performance. Therefore, the new catalytic combustion hydrogen sensor of the present invention is characterized by low cost, high stability, and excellent performance.
[0024] 3) The catalytic combustion type main element of the present invention employs a planar structure, and is characterized by a simple manufacturing process and stable structural performance. [Brief description of the drawings]
[0025] [Figure 1] Fig. 1 is a schematic diagram of the structure of a catalytic combustion type hydrogen sensor of the present invention, in which 101 is the bottom surface of a porous alumina sheet, 102 is a platinum resistor, 103 is an alumina thin film, 104 is the pore side of the porous alumina sheet, and 105 is palladium nanoparticles. [Figure 2a] Figure 2a is a comparison diagram of real-time current curves of different catalytic combustion hydrogen sensors at different hydrogen concentrations. [Figure 2b] Figure 2b shows a comparison of the relationship between different hydrogen concentrations and responsiveness for different catalytic combustion hydrogen sensors. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0026] The present invention will be further described below with reference to specific examples, but the scope of protection of the present invention is not limited thereto.
[0027] Working Example As shown in Fig. 1, the present invention relates to a highly responsive catalytic combustion hydrogen sensor based on a porous alumina support, in which the bottom surface 101 of a porous alumina sheet is an insulating substrate, a planar platinum resistor 102 is a measuring unit, and an alumina thin film 103 covers the surface of the platinum resistor 102. As shown in Fig. 1, palladium nanoparticles 105 are deposited as a catalyst on the pore side 104 of the porous alumina sheet to form a catalytic combustion element.
[0028] Example 1 A method for manufacturing a highly responsive catalytic combustion hydrogen sensor based on a porous alumina support includes the following steps.
[0029] (1) Selection of substrate: Select a porous alumina sheet with a thickness of 50 μm, the bottom surface of which is an insulating substrate, and the other surface of the porous alumina sheet has micro-nanoscale pores distributed thereon, the pore depth is 10-100 μm, the pore diameter is 50-400 nm, and the pore pitch is 65-400 nm.
[0030] (2) Platinum resistor fabrication: In order to increase the adhesion between the platinum resistor and the surface of the substrate, the porous alumina sheet is heated to 200°C, and then the electron beam evaporation method is adopted to deposit chromium with a thickness of about 6 nm on the bottom surface of the porous alumina sheet as an adhesive layer. Then, the same method is used to deposit the platinum resistor, and the power is about 20W. The pattern of the adhesive layer and the platinum resistor is realized by a metal mask, and the platinum resistor with a thickness of about 1 μm is fabricated by controlling the coating time, and the electrode gap of the platinum resistor is 0.2 mm. (See Li-Jun, Wang, Li-Yan, et al. Electrical performance of alumina films made in EB evaporation. [J].Modern Physics Letters B,2016.)
[0031] (3) Manufacturing of alumina thin film: A magnetron sputtering coating device is used to manufacture the alumina thin film, the sputtering power source is an RF power source, the target is an alumina target, the sputtering power is 170 W, the argon pressure in the sputtering chamber is maintained at about 1 Pa, and the thickness of the thin film is controlled to about 1 μm. The alumina layer uniformly covers the surface of the platinum resistor. (See DeyI. Microstructural studies of e-beam evaporated alumina thin films[J]. Surface Engineering, 2014.)
[0032] (4) Deposition of palladium nanoparticles: Palladium nanoparticles are deposited on the pore side of the porous alumina sheet using cluster beam deposition. The sputtering gas and buffer gas are both argon, the flow rates of the sputtering gas and buffer gas are 60sccm and 70sccm, respectively, the sputtering power is 15W, and the sputtering time is 4000s. Palladium nanoparticles are attached to both the surface of the sheet and inside the pores, and the size of the palladium nanoparticles is about 5nm. (See ACS Applied Materials & Interfaces,10(2018)44603-44613;CN200910028487.3).
[0033] Catalytic Combustion Performance Test A performance test is carried out on the catalytic combustion hydrogen sensor based on the porous alumina support manufactured by the above method. A voltage of about 1.7V is applied to the platinum resistor of the catalytic combustion hydrogen sensor, and the starting temperature of the catalytic combustion reaction between palladium nanoparticles and hydrogen reaches 110°C. In order to investigate the catalytic combustion effect of the two elements, two different catalytic combustion hydrogen sensors (one is a planar structure type, the other is a porous alumina support type) are placed in the test chamber in sequence, and hydrogen concentrations of 100 to 40,000 ppm are respectively injected into the chamber, and the current value of the platinum resistor is monitored in real time during the entire test process. In this test method, the real-time current curves of different catalytic combustion hydrogen sensors (one is a planar structure type, the other is a porous alumina support type) at different hydrogen concentrations are compared as shown in Figure 2a.
[0034] The planar catalytic element in FIG. 2a is a single-sided catalytic element obtained according to the method of Example 1 of the planar catalytic combustion hydrogen sensor based on a mica sheet previously applied for (see CN202210366188.6), and the porous catalytic element in FIG. 2a is a highly responsive and sensitive catalytic combustion hydrogen sensor based on a porous alumina support obtained in Example 1 of the present invention.
[0035] In addition, we compared the difference in response performance of catalytic combustion type hydrogen sensors depending on the calculation formula for the sensor response, and the calculation formula is as follows:
number
[0036] Based on the planar catalytic combustion hydrogen sensor based on mica sheet previously filed (see CN202210366188.6), the performance of the planar catalytic element and the porous alumina support catalytic combustion device in Example 1 of the present invention are compared, as shown in Figure 2b. As can be seen from Figure 2b, compared with the planar structure in which the insulating substrate is a mica sheet, the porous alumina support structure can greatly improve the catalytic combustion performance of hydrogen. For example, when the hydrogen concentration is 40,000 ppm, the response of the planar structure in which the insulating substrate is a mica sheet is 7.85%, while the response of the porous alumina support structure is 34.72%, that is, the response is improved by about 5 times.
[0037] In addition, a control catalytic combustion device was manufactured according to the method of Example 1 of the present application, with the difference being that "after the alumina thin film is manufactured in step (3), palladium nanoparticles are continuously deposited on the bottom surface of the porous alumina sheet according to the method of step (4)", and a catalytic combustion device was manufactured in which palladium nanoparticles were deposited on the bottom surface (non-porous side) of the porous alumina support for the same period of time. On the premise of matching the above test conditions, a performance test was carried out on the porous alumina support (bottom side) catalytic combustion device, and when the hydrogen concentration was 40,000 ppm, the responsiveness of the porous alumina support (bottom side) catalytic combustion device was 8.05%, that is, the responsiveness was improved by 4.3 times.
[0038] The present invention proposes a new type of catalytic combustion hydrogen sensor, and the catalytic combustion device based on the porous alumina support can greatly improve the catalytic combustion performance of hydrogen. In addition, the planar structure of the catalytic combustion hydrogen sensor substrate can not only avoid the problem of device failure in an on-board environment due to frequent mechanical vibration, but also avoid the drawbacks of the complex and expensive process of the MEMS catalytic combustion hydrogen sensor. As described above, the highly responsive and sensitive catalytic combustion hydrogen sensor based on the porous alumina support of the present invention has the characteristics of low cost, high stability and excellent performance, and is of great practical value in the safety monitoring of on-board hydrogen combustion cells.
[0039] It should be understood that the above contents of the specification are merely illustrative of the implementation of the inventive concept, and the protection scope of the present invention is not limited to the specific forms described in the embodiments.
[0040] (Additional Note) (Appendix 1) A highly responsive catalytic combustion hydrogen sensor based on a porous alumina support, comprising a porous alumina sheet, palladium nanoparticles, a platinum resistor and an alumina thin film; The porous alumina sheet has a single-pass structure, i.e., one side of the sheet has micro-nanoscale pores distributed thereon, and the other side is a pore-free flat surface, which is defined as the bottom surface of the porous alumina sheet; A platinum resistor and an alumina thin film carrier are attached in order to the bottom surface of the porous alumina sheet, the palladium nanoparticles are attached to the pore side of the porous alumina sheet, and the palladium nanoparticles are attached to both the surface of the sheet and inside the pores. A highly sensitive catalytic combustion type hydrogen sensor based on a porous alumina support.
[0041] (Appendix 2) Palladium nanoparticles are 1-100 nm in size and act as a catalyst, allowing hydrogen and oxygen gases to burn flamelessly under relatively mild conditions to generate heat. A highly responsive and sensitive catalytic combustion hydrogen sensor based on the porous alumina support described in appendix 1.
[0042] (Appendix 3) The alumina thin film covers the surface of the platinum resistor to prevent the platinum resistor from coming into contact with environmental gases. A highly responsive and sensitive catalytic combustion hydrogen sensor based on the porous alumina support described in appendix 1.
[0043] (Appendix 4) The single-pass porous alumina sheet supports a platinum resistor and carries a palladium nanoparticle catalyst, and the thickness of the sheet is in the range of 10-200 μm. The micro-nanoscale pore structure distributed on one side of the sheet has a pore depth of 5-180 μm, a pore diameter of 50-400 nm, and a pore pitch of 65-500 nm. A highly responsive and sensitive catalytic combustion hydrogen sensor based on the porous alumina support described in appendix 1.
[0044] (Appendix 5) The thickness of the platinum resistor is 0.5 to 10 μm, and the electrode gap of the platinum resistor is 0.05 to 5 mm. A highly responsive and sensitive catalytic combustion hydrogen sensor based on the porous alumina support described in appendix 1.
[0045] (Appendix 6) The thickness of the alumina thin film is 1 to 10 μm. A highly responsive and sensitive catalytic combustion hydrogen sensor based on the porous alumina support described in appendix 1.
[0046] (Appendix 7) A method for producing a catalytic combustion type hydrogen sensor having high response sensitivity based on the porous alumina support according to claim 1, comprising the steps of: Step 1) depositing a platinum resistor on the bottom surface of a porous alumina sheet by physical vapor deposition and realizing its pattern with a metal mask; Step 2) after depositing the platinum resistor, a layer of alumina thin film is produced on the surface of the platinum resistor by physical vapor deposition to uniformly coat the surface of the platinum resistor, and the platinum resistor is not exposed to environmental gas; 3) depositing palladium nanoparticles on the pore side of the porous alumina sheet using a cluster beam deposition instrument to attach palladium nanoparticles both to the surface of the sheet and inside the pores; A method for producing a highly responsive and sensitive catalytic combustion hydrogen sensor based on the porous alumina support described in Appendix 1, comprising:
[0047] (Appendix 8) In step 1), first, a 1-10 nm thick metal titanium or chromium thin film is deposited on the bottom surface of the porous alumina sheet using electron beam evaporation as an adhesive layer, and then a platinum resistor is further deposited using the same method, and its pattern is realized with a metal mask; 2. A method for producing a catalytic combustion type hydrogen sensor having high response sensitivity based on the porous alumina support according to claim 1.
[0048] (Appendix 9) In step 2), a magnetron sputtering coating equipment is used to deposit an alumina thin film, the sputtering power is an RF power supply, the target is an alumina target, the sputtering power is 100-200W, and the argon pressure in the sputtering chamber is maintained at 0.3-2Pa; 2. A method for producing a catalytic combustion type hydrogen sensor having high response sensitivity based on the porous alumina support according to claim 1.
[0049] (Appendix 10) In step 3), palladium nanoparticles are deposited on the pore side of the porous alumina sheet using a cluster beam instrument, the sputtering gas and buffer gas are both argon, the flow rates of the sputtering gas and buffer gas are 60-70sccm and 70-80sccm, respectively, the sputtering power is 5-30W, and the sputtering time is 3500-4500s; 2. A method for producing a catalytic combustion type hydrogen sensor having high response sensitivity based on the porous alumina support according to claim 1.
Claims
1. A highly responsive catalytic combustion hydrogen sensor based on a porous alumina support, comprising a porous alumina sheet, palladium nanoparticles, a platinum resistor and an alumina thin film; The porous alumina sheet has a single-pass structure, i.e., one side of the sheet has micro-nanoscale pores distributed thereon, and the other side is a pore-free flat surface, which is defined as the bottom surface of the porous alumina sheet; A platinum resistor and an alumina thin film carrier are attached in order to the bottom surface of the porous alumina sheet, the palladium nanoparticles are attached to the pore side of the porous alumina sheet, and the palladium nanoparticles are attached to both the surface of the sheet and inside the pores. A highly sensitive catalytic combustion hydrogen sensor based on a porous alumina support.
2. Palladium nanoparticles are 1-100 nm in size and act as a catalyst, allowing hydrogen and oxygen gases to burn flamelessly under relatively mild conditions to generate heat.
2. A catalytic combustion type hydrogen sensor having high response and sensitivity based on the porous alumina support according to claim 1.
3. The alumina thin film covers the surface of the platinum resistor to prevent the platinum resistor from coming into contact with environmental gases.
2. A catalytic combustion type hydrogen sensor having high response and sensitivity based on the porous alumina support according to claim 1.
4. The single-pass porous alumina sheet supports a platinum resistor and carries a palladium nanoparticle catalyst, the thickness of the sheet is in the range of 10-200 μm, and the micro-nanoscale pore structure distributed on one side of the sheet has a pore depth of 5-180 μm, a pore diameter of 50-400 nm, and a pore pitch of 65-500 nm; 2. A catalytic combustion type hydrogen sensor having high response and sensitivity based on the porous alumina support according to claim 1.
5. The thickness of the platinum resistor is 0.5 to 10 μm, and the electrode gap of the platinum resistor is 0.05 to 5 mm.
2. A catalytic combustion type hydrogen sensor having high response and sensitivity based on the porous alumina support according to claim 1.
6. The thickness of the alumina thin film is 1 to 10 μm.
2. A catalytic combustion type hydrogen sensor having high response and sensitivity based on the porous alumina support according to claim 1.
7. A method for producing a catalytic combustion type hydrogen sensor having high response sensitivity based on the porous alumina support according to claim 1, comprising the steps of: Step 1) depositing a platinum resistor on the bottom surface of the porous alumina sheet by physical vapor deposition and realizing its pattern with a metal mask; Step 2) after depositing the platinum resistor, a layer of alumina thin film is produced on the surface of the platinum resistor by physical vapor deposition to uniformly cover the surface of the platinum resistor, and the platinum resistor is not in contact with the environmental gas; 3) depositing palladium nanoparticles on the pore side of the porous alumina sheet using a cluster beam deposition instrument to deposit palladium nanoparticles both on the surface of the sheet and inside the pores; 2. A method for producing a catalytic combustion type hydrogen sensor having high response sensitivity based on the porous alumina support according to claim 1, comprising:
8. In step 1), first, a 1-10 nm-thick metallic titanium or chromium thin film is deposited as an adhesive layer on the bottom surface of the porous alumina sheet using electron beam evaporation, and then a platinum resistor is further deposited using the same method, and its pattern is realized with a metal mask; A method for producing a catalytic combustion type hydrogen sensor having high response sensitivity based on the porous alumina support according to claim 1.
9. In step 2), a magnetron sputtering coating equipment is used to deposit an alumina thin film, the sputtering power is an RF power supply, the target is an alumina target, the sputtering power is 100-200W, and the argon pressure in the sputtering chamber is maintained at 0.3-2Pa; A method for producing a catalytic combustion type hydrogen sensor having high response sensitivity based on the porous alumina support according to claim 1.
10. In step 3), palladium nanoparticles are deposited on the pore side of the porous alumina sheet using a cluster beam instrument, the sputtering gas and buffer gas are both argon, the flow rates of the sputtering gas and buffer gas are 60-70 sccm and 70-80 sccm, respectively, the sputtering power is 5-30 W, and the sputtering time is 3500-4500 s; A method for producing a catalytic combustion type hydrogen sensor having high response sensitivity based on the porous alumina support according to claim 1.