JP2005098742A - Catalytic combustion type hydrogen sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To miniaturize a sensor by using freely a technology of a thin film thermistor. <P>SOLUTION: This hydrogen sensor has a hydrogen reaction detection element 3. The hydrogen reaction detection element 3 is formed, by laminating a catalyst layer 4 for hydrogen reaction and a temperature detection layer 5. The catalyst layer 4 for hydrogen reaction is a layer which generates a heat by a reaction with hydrogen gas. The temperature detection layer 5, which is the thin film thermistor detects a heat generation temperature of the hydrogen reaction catalyst layer generated by a change of the hydrogen concentration, detects the heat generation temperature in a reaction time of 3-5 seconds, and outputs the result. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a catalytic combustion type hydrogen sensor for a fuel cell.

  Fuel cells, particularly polymer electrolyte fuel cells, have attracted a great deal of attention as fuel cells for automobiles because pure water is used as the fuel and only water is discharged. A polymer electrolyte fuel cell has an air electrode (oxygen electrode) and a hydrogen electrode with an ion exchange membrane sandwiched between them, current collectors are arranged on the outside, and separators are arranged on the outermost side. One cell is constructed. In the fuel cell, the following chemical reaction occurs.

That is, when the hydrogen gas of the fuel is sent to the cell and reacts with the catalyst of the hydrogen electrode, electrons jump out and become H ⁺ (H ₂ → 2H ⁺ + 2e ⁻ ). This proton passes through the ion exchange membrane and goes to the air electrode on the opposite side. The oxygen in the air sent by the air electrode reacts with H ⁺ and e ⁻ which returns after finishing work with the power of the catalyst. To water (O ₂ + 4H ⁺ + 4e ⁻ → 2H ₂ O). The structure of the improved polymer electrolyte fuel cell is described in Patent Document 1, for example.

  This series of operating temperatures is performed at 80-90 ° C. Since about 0.7V is obtained with one cell, for example, in a fuel cell in which 300 cells are stacked, a voltage of 210V can be obtained with one cell (see Non-Patent Document 1). Detecting whether the fuel cell is operating normally or detecting hydrogen gas leaks is an important matter for using the fuel cell or for safety management. Can be detected by a hydrogen sensor.

  Currently, there are three known hydrogen sensors in practical use: a hot-wire semiconductor sensor, a gas heat conduction sensor, and a catalytic combustion sensor.

  The hot-wire semiconductor sensor is a sensor that uses a platinum wire coil coated with a metal oxide semiconductor paste and fired as a porous body, and is negatively ionized and adsorbed on the surface of the semiconductor element due to the presence of flammable gas. Oxygen is consumed, and at the same time, free electrons are generated to make the semiconductor in a low resistance state, which is paired with a fixed resistance to extract a voltage as a bridge output. The 90% response time is within 20 seconds.

  The gas thermal conductivity sensor is a sensor that uses the difference in thermal conductivity between a standard gas (usually air) and a target gas. Again, the temperature change of the sensing element is paired with the temperature compensation element and taken out as a bridge output. The 90% response time is 5-10 seconds.

  The contact combustion type sensor uses a platinum wire coil sintered with alumina particles carrying a noble metal catalyst as a detection element. The platinum wire coil is a heater that heats the element and a temperature measurement. It also serves as a temperature resistor. When air containing a combustible gas is brought into contact, the temperature of the sensing element rises due to catalytic combustion, and the resistance value of the platinum wire increases. This is paired with a temperature compensation element to extract a voltage corresponding to the gas concentration as a change in bridge voltage. Compared with the contact combustion type sensor hot wire type semiconductor sensor, the linearity between the detected gas concentration and the output (sensitivity) is good, and the 90% response time is 5 to 10 seconds (see Non-Patent Document 2).

  However, existing hydrogen sensors are not only expensive, but also have problems such as slow response speed, lack of selectivity, and other types of mixed gases that can cause deterioration and damage to the sensor. It is difficult to adapt to a fuel cell system that requires high concentration hydrogen measurement. For example, when a gas leak of hydrogen gas is detected, if the 90% response speed is 10 to 20 seconds, the detection takes too much time and it is not practical. As an attempt to improve the responsiveness of the gas heat conduction sensor, a combination of a detection element in which the first thermistor is accommodated in the perforated case and a reference element in which the second thermistor is accommodated in the non-porous case is used. A hydrogen sensor that detects the difference in voltage between the resistance value of the first thermistor that has been heated by being heated by contact with hydrogen and the resistance value of the second thermistor that is not cooled and does not change its resistance value. It has been proposed (see Patent Document 2).

  In short, this hydrogen sensor seems to be merely a diversion of a conventional humidity sensor using a conventional thermistor to detect hydrogen. As a new attempt to improve the hydrogen gas detection accuracy of the catalytic combustion type sensor, a thermoelectric exchange type hydrogen gas sensor was proposed by Sue-suk et al. (See Non-Patent Document 3).

  The operation principle of the thermoelectric exchange type hydrogen gas sensor proposed by Seo-suk is to convert the local temperature difference generated from the catalyst heat generation of the hydrogen gas and the Pt catalyst into a voltage signal by the thermoelectric conversion material. In a report by Woo-Suk et al., The attempt to use the catalytic reaction heat of platinum as a signal trigger states that the McAleer report in 1985 is the first and only report.

  In the report by Woo-suk et al., Referring to the results of research on materials for nickel oxide doped with Li as a thermoelectric conversion material, a thermal oxide paste with an optimal composition was created, and the paste was printed on an alumina substrate. A thick thermoelectric conversion oxide film was created by firing in, and then a platinum layer as a catalyst was formed to a thickness of several to several tens of nm using a sputtering device on the surface of the thermoelectric conversion oxide thick film. According to this hydrogen sensor, the operating range is considered to be appropriate in the range of 80 to 100 ° C. Future issues include improved durability and responsiveness. The necessity of is discussed.

  An example in which a catalytic combustion type sensor is used as means for detecting the end of charging of a nickel-metal hydride battery is described in Patent Document 3.

  In this example, a power generation element is supported for the purpose of detecting the end of charge or the time of oxygen generation of a nickel-metal hydride battery used as a power source mounted on a spacecraft such as an artificial satellite or a power source of an automobile. Then, an oxygen / hydrogen reaction catalyst layer is attached to the inner wall of the battery case, and a temperature detection sensor is provided on the outer wall of the battery case to oppose the catalyst layer.

  The nickel-metal hydride battery described in Patent Document 3 does not use a combination of a catalyst layer and a thermistor for the purpose of detecting the normal supply of gas or the presence or absence of gas leakage. The concept of detecting the generation of gas by detecting the temperature of the catalyst layer raised by the catalytic reaction with the temperature sensor is basically the same as the concept of the thermoelectric exchange type hydrogen gas sensor described in Non-Patent Document 2. The same.

  However, the use of bulk type thermistors limits the miniaturization of the shape and not only can meet the demands of sensor downsizing, energy saving design, high responsiveness, etc., but also a sheet-like catalyst on the inner wall of the battery case. A layer is provided so as to face the power generating element, and a thermistor is attached to the outer wall of the battery case against the catalyst layer with an adhesive or the like, so that there is no normal gas supply or gas leakage The hydrogen concentration depends solely on the reaction temperature of the catalyst layer, but the above structure does not seem to accurately detect the reaction temperature of the catalyst.

Thus, until now, although the search for the practical use of the sensor concept for converting the voltage signal to the thermoelectric conversion material generated from the catalyst heat generation of the gas and the catalyst has been continued, it has not yet reached the practical level. Was the actual situation.
JP 2001-76742 A Japanese Patent Laid-Open No. 2003-130834 Japanese Patent Laid-Open No. 10-162863 TRIGGER 2000 JUL Special Feature Impact of Fuel Cell Revolution p5-9 Advanced Natural Gas Utilization Technology Supervised by Masaru Ichikawa April 10, 2000 Ceramics 2003 No. 6 Special Feature Development of New Ceramic Sensors P430-433

  The problem to be solved is that, with regard to hydrogen sensors, especially catalytic combustion type hydrogen sensors, the heat generation temperature of the catalyst layer generated by the reaction between the gas and the catalyst is accurately detected, and the durability and responsiveness are specified to practical levels. It was a point that could not be realized.

  The main feature of the present invention is that the thin film thermistor technology is used to reduce the size of the sensor to improve the response and to accurately measure the hydrogen gas concentration in comparison with the ambient temperature. And

  The catalytic combustion type hydrogen sensor of the present invention can detect a local temperature difference generated from catalyst heat generation between hydrogen gas and a hydrogen reaction catalyst layer, and measure the absolute concentration of hydrogen gas from the temperature difference. it can. In particular, the thin film thermistor selected as the temperature detection layer has a large temperature coefficient, so that a large signal can be taken out with low power consumption, and responsiveness can be improved. For the hydrogen reaction catalyst layer, platinum or a platinum-based catalyst is used. However, for example, use of a palladium catalyst is also conceivable.

  The catalytic combustion type hydrogen-hydrogen sensor is a laminate of a thin film thermistor and a platinum catalyst layer. The thermal temperature difference generated by the catalytic reaction between the hydrogen gas and the platinum catalyst is converted into a voltage signal by the thin film thermistor. On the other hand, the environmental temperature is detected by a thin film thermistor for temperature compensation, and the detection temperature of the thin film thermistor for temperature compensation and the detected temperature of the thin film thermistor on which the platinum catalyst layer is laminated are the purpose of accurately detecting the hydrogen gas concentration. Realized by comparison.

  FIG. 1 is a diagram showing a basic configuration of a catalytic combustion type hydrogen sensor of the present invention. 1A and 1B, a catalytic combustion type hydrogen sensor 1 according to the present invention has a hydrogen reaction detecting element 3. The hydrogen reaction detecting element 3 is formed by stacking a substrate 2, a hydrogen reaction catalyst layer 4, and a temperature detecting layer 5. There are a hydrogen reaction catalyst layer 4 and a temperature detection layer 5 on the substrate 2, the hydrogen reaction catalyst layer 4 is a layer that generates heat in response to hydrogen gas, and the temperature detection layer 5 has a change in hydrogen concentration. Detects the exothermic temperature of the hydrogen reaction catalyst layer produced by, and detects the hydrogen concentration from the exothermic temperature.

  In the present invention, the temperature detection layer 5 is a thin film thermistor formed on the electrode 6 of the substrate 2. As the substrate 2, either glass, ceramics or single crystal is usually selected and used, but it is desirable to use an alumina substrate with little thermal strain. The electrodes 6 form a pair of combs that are inserted into the gaps, and the resistance value of the thermistor is adjusted by adjusting the shape, number of combs, or the distance between the electrodes. The thin film thermistor detects the exothermic temperature of the hydrogen reaction catalyst layer caused by the change in the hydrogen concentration, and detects the hydrogen concentration from the resistance value of the thermistor that decreases as the exothermic temperature increases.

  The thin film thermistor which is the temperature detection layer 5 is a vapor deposition film of a composition in which transition metals such as manganese, cobalt, iron and nickel are blended at a predetermined ratio and set to a predetermined resistance value. It is layered with a constant area and a constant thickness within the range of the substrate.

  The surface of the thin film thermistor which is the temperature detection layer 5 is covered with an insulating layer 7 such as a glass coat, and the hydrogen reaction catalyst layer 4 has a Pt catalyst film on the surface of the insulating layer 7 to a thickness of several to several tens of nm. It is formed by stacking by sputtering deposition.

  In the catalytic combustion type hydrogen sensor 1 according to the present invention, an environmental temperature detection element 8 is combined with a hydrogen reaction detection element 3 as shown in FIG. The environmental temperature detecting element 8 compensates for the value of the electric signal due to the temperature of the environment where the hydrogen reaction detecting element 3 is placed. The environmental temperature detection element 8 has a temperature detection layer 5a. The temperature detection layer 5 a is a thermistor, and it is necessary to select a thermistor having the same resistance-temperature characteristics as the thin film thermistor used for the temperature detection layer 5 of the hydrogen reaction detection element 3.

  The thermistor used as the temperature detection layer 5a of the environmental temperature detection element 8 always detects the temperature of the environment in which the hydrogen reaction detection element 3 is placed according to the resistance value, and the thermistor resistance changed by the temperature rise of the hydrogen reaction detection element 3 Compensates for changes in value. The shape and structure of the thermistor used for the environmental temperature detection element 8 are not limited, but the same characteristics as the thin film thermistor used for the temperature detection layer 5 of the hydrogen reaction detection element 3 may be used as the temperature detection layer 5a. This is advantageous in manufacturing the sensor.

  In FIG. 2, a layer obtained by removing the hydrogen reaction catalyst layer from the hydrogen reaction detecting element, that is, a temperature detecting layer (thin film thermistor) 5a stacked across a pair of the substrate 2a and the comb-shaped electrode 6a of the substrate 2a. And an insulating layer 7a covering the temperature detection layer 5a. According to this configuration, if a hydrogen reaction catalyst layer is laminated on the insulating layer 7a of the environmental temperature detection element 8, a hydrogen reaction detection element is obtained.

  In short, the environmental temperature detection element 8 is placed under the same conditions as the hydrogen reaction detection element 3, and only needs to be able to measure the temperature of the environment in which the hydrogen reaction detection element 3 is placed, and is not necessarily limited to the structure shown in FIG. Is not to be done. The temperature detection layer 5a does not necessarily have to be laminated on the substrate 2a. For example, a bead-type thermistor sealed with glass can be used as the environmental temperature detection element 8.

  As shown in FIG. 3, the hydrogen reaction detection element 3 and the environmental temperature detection element 8 are installed in the same environment by being attached to the base plate 9 at a predetermined interval, for example. The distance between the hydrogen reaction detection element 3 and the environmental temperature detection element 8 is such a distance that the influence of heat generated on the hydrogen reaction catalyst layer 4 of the hydrogen reaction detection element does not affect the thermistor of the environmental temperature detection element 8. If it can secure.

  In order to protect the hydrogen reaction detection element 3 and the environmental temperature detection element 8 from unexpected impacts, the lead wire 11 housed in, for example, the net case 10 and drawn from the electrode of the hydrogen reaction detection element 3, and the environment The lead wire 12 drawn from the electrode of the temperature detecting element 8 is connected between the terminals ac, ad on the two sides of the bridge circuit 13 shown in FIG. Resistors R1 and R2 are connected between the two terminals c-b and b-d, respectively.

  Assuming that the resistance of the hydrogen reaction detecting element 3 is Rr and the resistance of the environmental temperature detecting element 8 is Rt, the product of the opposing resistances is equal when the bridge circuit 13 is in an equilibrium state with the DC voltage V1 applied. Rr · R2 = Rt · R1 and the voltage across the resistance Rr of the hydrogen reaction detecting element 3 and the resistance Rt of the environmental temperature detecting element 8 is Rr · Ir = Rt · It according to Ohm's law. For example, the voltage Vca across the resistor Rr of the hydrogen reaction detecting element 3 and the voltage Vda across the resistor Rt of the environmental temperature detecting element 8 satisfy the relationship Vca = Vda, and the potential difference between the cd terminals is 0. Become.

  When the catalytic combustion type hydrogen sensor of the present invention is installed in the hydrogen gas supply piping system of the fuel cell, if the bridge circuit 13 is set so as to maintain an equilibrium state, the voltmeter can be used when hydrogen gas is not supplied to the fuel cell. No current flows through 14. Next, when hydrogen gas is supplied to the fuel cell, on the hydrogen reaction detecting element 3 side of the catalytic combustion type hydrogen sensor, the hydrogen reaction catalyst layer 4 generates heat due to the catalytic reaction by touching the supplied hydrogen gas. While the exothermic temperature is detected by the thin film thermistor which is the temperature detection layer 5 and the resistance value Rr changes, the resistance value Rt of the environmental temperature detection element 8 is determined by the temperature of the hydrogen gas supply piping system, and the fuel cell is 80 When operating near ˜100 ° C., the resistance value is maintained at a constant value with the ambient temperature of 80-100 ° C.

  As a result, the equilibrium state of the bridge circuit 13 is lost, and there is a difference between the voltage Vac across the resistor Rr of the hydrogen reaction detecting element 3 and the voltage Vda across the resistor Rt of the environmental temperature detecting element = Vda. Arise. That is, an electric signal proportional to the heat generation temperature of the hydrogen reaction catalyst layer 4 that causes the change in the resistance value Rr of the hydrogen reaction detecting element 3, that is, the hydrogen gas concentration is output. In the present invention, since the hydrogen reaction detecting element is a thin film thermistor, it has excellent responsiveness, accurately detects the exothermic temperature of the catalyst layer generated by the reaction between hydrogen gas and the catalyst, and outputs a signal in a short time. .

FIG. 5 shows an example in which the hydrogen reaction detecting element 23 of the catalytic combustion hydrogen sensor 21 and the environmental temperature detecting element 28 are formed on the same substrate 22. The substrate 22, the hydrogen responsive detector forming region Z _23, a formation area Z ₂₈ of the environmental temperature detecting element has a substantially U-shape is partitioned into a common terminal forming region Z _T. Hydrogen responsive detector forming region Z ₂₃ is an end portion of the elongated U-shaped laminating a hydrogen reaction catalyst layer 24 and the temperature sensing layer 25, the ambient temperature detection element forming region Z _28, the temperature sensing layer 25a The common terminal forming region Z _T is a bottom portion of a horizontally long U character that connects the hydrogen reaction detecting element forming region Z ₂₃ and the environmental temperature detecting element forming region Z _28. It is.

The hydrogen reaction detecting element forming region Z ₂₃ and the environmental temperature detecting element forming region Z ₂₈ are supported by the common terminal forming region Z _T of the substrate 22 and are kept at an interval at which the thermal effect due to the catalytic reaction of hydrogen gas does not become a problem. ing. Hydrogen responsive detector forming region Z _23, to the environmental temperature detection element forming region Z ₂₈ are comb electrodes 26,26a of each thin film thermistor formed, the common terminal forming region Z _T, both the thin film thermistor A common electrode 29 communicating with the comb-shaped electrodes 26 and 26a is formed. Hydrogen responsive detector forming region _{Z 23,} the comb electrodes 26,26a environmental temperature detection element forming region _{Z 28,} deposited film of each thin film thermistor separately as a temperature sensing layer 25,25a are attached, on which to subjected to common insulating film 27, further, on the insulating film 27 of the hydrogen responsive detector forming region Z _23, catalytic combustion type hydrogen sensor 21 catalyst layer 24 is a hydrogen reactions are stacked is completed.

The lead wires 11 and 12 are pulled out from the comb-shaped electrodes 26 and 26a of the temperature detection layers 25 and 25a, and connected to a bridge circuit to function as a catalytic combustion type hydrogen sensor. It is. According to this embodiment, the hydrogen responsive detector forming region Z ₂₃ on the common substrate 22, sequentially assigned in the temperature sensing layer and the insulating layer on the electrode of the environmental temperature detection element forming region Z _28, further hydrogen responsive detector forming region Z ₂₃ can be produced easily catalytic combustion type hydrogen sensor by subjecting the hydrogen reaction catalyst layer 24.

  In the present invention, the resistance value of the environmental temperature detecting element is determined only by the environmental temperature including the operating temperature of the fuel cell. The resistance value Rr of the hydrogen reaction detecting element is determined by adding hydrogen gas and hydrogen in addition to the environmental temperature. Since it is determined by the exothermic temperature generated by the catalytic reaction with the reaction catalyst layer, as long as the NTC is used for the thermistor, the resistance Rr = Rt of the environmental temperature sensing element or the equilibrium of the bridge circuit 13 is always used during the operation of the fuel cell. By monitoring the collapse of the state, it can be seen that hydrogen gas is normally supplied to the fuel cell.

  Exactly the same, when the catalytic combustion type hydrogen gas sensor according to the present invention is installed in the vicinity of the outside of the fuel cell, an electric signal is generated by reacting immediately when hydrogen gas leaks from the fuel cell, The fact of gas leakage can be easily detected.

In the present invention, since a thin film thermistor is selectively used for the temperature detection layer, the sensor can be thinned and miniaturized, has excellent responsiveness, and can achieve high sensitivity. An example of the size of the sensor shown in FIG. 1 and its laminated structure is shown below.
Substrate 1mm x 0.2-0.5mm
Comb-shaped electrode 2-3 μm
Thin film thermistor film thickness 2-3μm (less than 5μm)
Insulating film 1 μm or less Hydrogen reaction catalyst layer Several to several tens of nm
With respect to the catalytic combustion type hydrogen gas sensor composed of the above laminated layers, a 90% reaction time of 3 to 5 seconds could be realized under a normal B constant.

  The resistance value of the thin film thermistor can be determined not only by the selection of the composition of the target material of the thin film thermistor and the film thickness, but also by the comb shape of the comb-shaped electrodes and the interval between the paired comb-shaped electrodes.

  By selecting a thin-film thermistor for the temperature detection layer, thermal response is improved, miniaturization and thickness reduction can be realized, and the mechanical strength is increased by covering the surface with an insulating layer. It is possible to solve the problems of the hydrogen gas sensor at once and use it for actual applications such as fuel cell operation confirmation and hydrogen gas gas leak detection.

The hydrogen reaction detection element of the catalytic combustion type hydrogen sensor by this invention is shown, (a) is a partial cross section top view, (b) is the BB sectional drawing of (a). FIG. 2 is a longitudinal sectional view showing a part corresponding to the line BB in FIG. It is a figure which shows an example of the structure of the contact combustion type hydrogen sensor by this invention. It is a bridge circuit which comprises the contact combustion type hydrogen sensor by this invention. The other example of the structure of the catalytic combustion type hydrogen sensor by this invention is shown, (a) is a partial cross section top view, (b) is CC sectional view taken on the line of (a).

Explanation of symbols

1, 21 Catalytic combustion type hydrogen sensor 2 (2a) 22 Substrate 3, 23 Hydrogen reaction detection element 4, 24 Hydrogen reaction catalyst layer 5 (5a) 25 (25a) Temperature detection layer 6 (6a) 26 Electrode 7 (7a) 27 Insulating layers 8 and 28 Ambient temperature detecting element 9 Base plate 10 Net case 11 Lead wire 12 Lead wire 13 Bridge circuit 14 Voltmeter 29 Common electrode

Claims (9)

A catalytic combustion type sensor having a hydrogen reaction detecting element,
The hydrogen reaction detection element has a laminate of a hydrogen reaction catalyst layer and a temperature detection layer,
The hydrogen reaction catalyst layer is a layer that generates heat in response to hydrogen gas,
The temperature detection layer is a thin film thermistor that detects the exothermic temperature of the hydrogen reaction catalyst layer caused by changes in the hydrogen concentration and detects the hydrogen concentration from the resistance value of the thermistor that decreases as the exothermic temperature rises. Features a catalytic combustion type hydrogen sensor. A catalytic combustion type hydrogen sensor having a hydrogen reaction detecting element and an environmental temperature detecting element,
The hydrogen reaction detection element has a laminate of a hydrogen reaction catalyst layer and a temperature detection layer,
The hydrogen reaction catalyst layer is a layer that generates heat in response to hydrogen gas,
The temperature detection layer is a thin film thermistor that detects the exothermic temperature of the hydrogen reaction catalyst layer caused by the change in hydrogen concentration, and detects the hydrogen concentration from the resistance value of the thermistor that decreases as the exothermic temperature increases.
The environmental temperature sensing element has a temperature sensing layer,
The temperature detection layer is a thermistor and shows the same resistance value as the thin film thermistor of the temperature detection layer. The temperature value of the environment where the hydrogen reaction detection element is placed is always detected by the resistance value of the thermistor, and the temperature rise of the hydrogen reaction detection element A catalytic combustion type hydrogen sensor that compensates for a change in the changed resistance value of the thermistor. The temperature detection layer of the environmental temperature detection element is a thin film thermistor, and the environmental temperature detection element is composed of a layer obtained by removing a hydrogen reaction catalyst layer from a hydrogen reaction detection element. The contact combustion type hydrogen sensor described in 1. The thin film thermistor is formed on the electrode of the substrate,
The electrodes have a comb shape that forms a pair inserted into the gap, and the resistance value of the thin film thermistor is adjusted by adjusting the shape, number of the comb shape, or the distance between the electrodes. The catalytic combustion type hydrogen sensor according to claim 1 or 2. A thin film thermistor is a vapor deposition film of a composition set to a predetermined resistance value by blending transition metals such as manganese, cobalt, iron, nickel, etc., straddling between both comb-shaped electrodes and within the range of the substrate. The catalytic combustion type hydrogen sensor according to claim 1 or 2, wherein the contact combustion type hydrogen sensor is laminated with a constant area and a constant thickness. The surface of the thin film thermistor is covered with an insulating layer, and the hydrogen reaction catalyst layer is laminated by sputtering a Pt catalyst film to a thickness of several to several tens of nanometers on the surface of the insulating layer. The catalytic combustion type hydrogen sensor according to claim 1 or 2. The environmental temperature detection element covers a stack obtained by removing the hydrogen reaction catalyst layer from the hydrogen reaction detection element, that is, a temperature detection layer stacked across a pair of a substrate and a comb-shaped electrode of the substrate, and a temperature detection layer. The contact combustion type hydrogen sensor according to claim 1 or 2, wherein the contact combustion type hydrogen sensor is constituted by lamination with an insulating layer. The catalytic combustion type hydrogen sensor according to claim 2, wherein the hydrogen reaction detecting element and the environmental temperature detecting element are separately formed on the same substrate. The substrate is partitioned into a hydrogen reaction detection element formation region, an environmental temperature detection element formation region, and a common terminal formation region,
The hydrogen reaction detection element formation region is a portion where the hydrogen reaction catalyst layer and the temperature detection layer are laminated,
The common terminal formation region is a portion connecting the hydrogen reaction detection element formation region and the formation region of the environmental temperature detection element,
The formation area of the environmental temperature detection element is a portion where the thin film thermistors are stacked, and the electrode of the thin film thermistor is formed in each of the hydrogen reaction detection element formation area and the environmental temperature detection element formation area. Has a common electrode for both thin film thermistors,
4. The catalytic combustion type according to claim 3, wherein the hydrogen reaction detecting element forming region and the environmental temperature detecting element forming region are maintained at an interval at which a thermal effect due to a contact reaction of hydrogen gas does not become a problem. Hydrogen sensor.

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