JP5055597B2 - Hydrogen sensor - Google Patents

Description

  The present invention relates to a hydrogen sensor that detects hydrogen.

  In recent years, the use of hydrogen as energy has attracted attention due to growing interest in environmental and resource issues. Among them, fuel cells are rapidly developed as a clean energy system using hydrogen in the fields of household power generation systems and automobiles. Therefore, it is expected that the technical field of fuel cells will further develop in the future.

  By the way, hydrogen needs to be handled with care because of the danger of explosion. For this reason, also in the fuel cell described above, a hydrogen sensor that detects hydrogen leakage is indispensable.

  Conventionally, semiconductor-type hydrogen sensors using tin oxide have been widely used as methods for detecting hydrogen. However, this semiconductor-type hydrogen sensor has drawbacks that it requires heating because of its high operating temperature of about 400 ° C. and is expensive.

Thus, a hydrogen sensor that operates at room temperature has been proposed in which a magnesium / palladium alloy thin film is formed on a glass substrate and a catalyst layer made of palladium, platinum, or the like is formed thereon (see Patent Document 1). ). However, although the hydrogen sensor described in Patent Document 1 can detect hydrogen at room temperature, it has the drawbacks of low response speed and low detection accuracy.
JP 2007-71547 A

  The present invention has been proposed in view of such conventional circumstances, and an object of the present invention is to provide a hydrogen sensor that enables hydrogen detection at room temperature and has a high response speed.

To this end, the hydrogen sensor according to the present invention, the hydrogen sensor for detecting hydrogen by having nanowires consisting of hydrogen brittle material, the nanowire detects that disconnection by reacting with hydrogen And a support member provided with an opening, and a pair of lead frames disposed at positions facing the opening of the support member, the pair of lead frames from the base end portion toward the tip end portion. The nanowires are arranged in a state of being pointed and faced to each other, and the nanowires are arranged in a bridged state between the tip parts of the pair of lead frames .
In this hydrogen sensor, it is possible to detect hydrogen at room temperature and increase its response speed by using for detecting hydrogen that a nanowire made of a hydrogen-brittle material reacts with hydrogen and breaks. Further, when hydrogen passing through the opening of the support member comes into contact with the nanowire cross-linked between the tip portions of a pair of lead frames arranged at the position facing the opening, the nanowire reacts with hydrogen. And it becomes easy to break. Therefore, it is possible to improve the hydrogen detection accuracy.
Further, in the hydrogen sensor according to the present invention, the support member includes a frame portion that forms an opening and a pair of leg portions that support the frame portion, and the frame corresponds to the height of the pair of leg portions. It is preferable to set it as the structure installed in an installation surface in the state which floated the part.
Further, in the hydrogen sensor according to the present invention, the pair of leg portions are arranged at positions along two opposing sides constituting the frame portion, and the pair of lead frames constitute one frame portion. It is preferable that the base end portion is fixed to the two opposite sides.

Moreover, it is preferable that the thickness of the said nanowire is 100 nm or less.
Thereby, the response speed of hydrogen detection can be increased. In addition, about the minimum of the thickness of nanowire, what is necessary is just the limit value of the thickness which can be physically formed.

The hydrogen sensor according to the present invention, it is preferable to adopt a configuration of arranging one or more even on SL nanowires small without.

  As described above, according to the present invention, it is possible to provide a hydrogen sensor that can detect hydrogen at room temperature and has a high response speed.

Hereinafter, a hydrogen sensor to which the present invention is applied will be described in detail with reference to the drawings.
In addition, in the drawings used in the following description, in order to make the features easy to understand, there are cases where the portions that become the features are enlarged for the sake of convenience, and the dimensional ratios of the respective components are not always the same as the actual ones. Absent.

FIG. 1 is a perspective view showing an example of a hydrogen sensor 1 to which the present invention is applied, and FIG. 2 is a longitudinal sectional view showing the structure of the hydrogen sensor 1 shown in FIG.
As shown in FIGS. 1 and 2, the hydrogen sensor 1 to which the present invention is applied has nanowires W made of a hydrogen brittle material, and detects that the nanowires W are disconnected by reacting with hydrogen. It is characterized by detecting hydrogen.

Specifically, the hydrogen sensor 1 includes a support member 2 and a detection unit 3 supported by the support member 2.
The support member 2 is made of an insulating member having rigidity such as glass. Although the shape of the support member 2 is not particularly limited, the support member 2 includes, for example, a frame portion 4 in which an opening 2 a is formed and a pair of leg portions 5 a and 5 b that support the frame portion 4.

  The frame part 4 is formed in a rectangular frame shape in plan view, and has a rectangular opening 2a at the center thereof. That is, the frame portion 4 is configured to have one opposite two sides 4a and 4b surrounding the periphery of the opening 2a and another opposite two sides 4c and 4d orthogonal to the two sides 4a and 4b.

The pair of leg portions 5 a and 5 b are formed integrally with the frame portion 4 along one opposing two sides 4 a and 4 b constituting the frame portion 4 . The pair of leg portions 5 a and 5 b have a predetermined height dimension from the lower surface of the frame portion 4 . Thereby, the opening 2a of the support member 2 is in a state of floating above the installation surface on which the support member 2 is installed by the height of the frame 4 supported by the pair of legs 5a and 5b. ing.

  The detection unit 3 includes nanowires W made of a hydrogen brittle material, and detects that the nanowires W are disconnected by reacting with hydrogen. Specifically, the detection unit 3 has a pair of lead frames 6 a and 6 b at positions facing the opening 2 a of the support member 2. The pair of lead frames 6a and 6b is made of a conductive metal member such as aluminum or titanium, and has a flat plate shape that is pointed from the base end portion toward the tip end portion. The pair of lead frames 6a and 6b are fixed to one opposite two sides 4a and 4b constituting the frame portion 4 with their respective distal ends facing each other. It is arranged facing the opening 2 a of the support member 2.

  The nanowire W is provided in a bridged state between the tip portions of the lead frames 6a and 6b facing each other. For the nanowire W, for example, silver or copper can be used as a hydrogen brittle material. Moreover, it is preferable that the thickness of the nanowire W is 100 nm or less. By forming the nanowire W thin, the response speed of hydrogen detection described later can be increased. In addition, about the minimum of the thickness of nanowire W, what is necessary is just the limit value of the thickness which can be physically formed, and the limit value is about 1 nm, for example. Moreover, as a preparation method of nanowire, there exists a method etc. which synthesize | combine nanowire by irradiating an electron beam to the base | substrate which hold | maintained silver ion, for example. According to this method, metallic silver nanowires having a diameter of several to several tens of nanometers can be easily generated.

  Electrode pads 7a and 7b for external connection are provided on the base end portions of the pair of lead frames 6a and 6b, respectively. These electrode pads 7a and 7b are made of a conductive metal member such as aluminum, and are electrically connected to the pair of lead frames 6a and 6b.

  In the hydrogen sensor 1 having the above-described structure, a minute current supplied from an external power source connected to the electrode pads 7a and 7b can be supplied to the nanowire W through the pair of lead frames 6a and 6b. It is possible. And in this hydrogen sensor 1, if it exposes to the atmosphere containing hydrogen by hydrogen leakage etc. in the energized state, the nanowire W will react with hydrogen and will be disconnected. At this time, since power to the nanowire W is interrupted, hydrogen (hydrogen leakage) can be detected quickly at room temperature by detecting this.

  As described above, in the hydrogen sensor 1 to which the present invention is applied, it is possible to detect hydrogen at room temperature by using the fact that the nanowire W made of a hydrogen brittle material reacts with hydrogen and is disconnected for hydrogen detection. In addition, the response speed when detecting hydrogen can be greatly increased. Further, the hydrogen sensor 1 can detect hydrogen only by passing a minute current, and is very energy saving.

In addition, this invention is not necessarily limited to the thing of the said embodiment, A various change can be added in the range which does not deviate from the meaning of this invention.
For example, the hydrogen sensor 1 has a configuration in which the nanowires W are disposed between the tip portions of the lead frames 6a and 6b. It suffices that at least one is disposed in a cross-linked state at a position facing the opening 2a. Thereby, when the hydrogen passing through the opening 2a of the support member 2 comes into contact with the nanowire W cross-linked at the position facing the opening 2a, the nanowire W easily reacts with hydrogen and breaks. . Therefore, it is possible to improve the hydrogen detection accuracy. In addition, when a plurality of nanowires W are arranged, it is possible to further increase the response speed to hydrogen detection by detecting that any nanowire W is disconnected.

  The hydrogen sensor 1 has a configuration using a metal material for the lead frames 6a and 6b and the electrode pads 7a and 7b. However, the configuration is not limited to this, and a semiconductor substrate such as silicon is used. It is also possible to form these integrally.

FIG. 1 is a perspective view showing an example of a hydrogen sensor to which the present invention is applied. FIG. 2 is a longitudinal sectional view of the hydrogen sensor shown in FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Hydrogen sensor 2 ... Support member 2a ... Opening part 3 ... Detection part 4 ... Frame part 5a, 5b ... Leg part 6a, 6b ... Lead frame 7a, 7b ... Electrode pad

Claims (5)

A hydrogen sensor having a nanowire made of a hydrogen-brittle material and detecting hydrogen by detecting that the nanowire has broken by reacting with hydrogen,
A support member provided with an opening;
A pair of lead frames arranged at positions facing the opening of the support member,
The pair of lead frames are pointed from the proximal end portion toward the distal end portion, and arranged with the distal end portions facing each other.
2. The hydrogen sensor according to claim 1, wherein the nanowire is disposed in a bridged state between the tip portions of the pair of lead frames . The support member includes a frame part that forms the opening and a pair of leg parts that support the frame part, and the frame part floats according to the height of the pair of leg parts. The hydrogen sensor according to claim 1, wherein the hydrogen sensor is installed on an installation surface. The pair of leg portions are arranged at positions along two opposing two sides constituting the frame portion,
3. The hydrogen sensor according to claim 2, wherein the pair of lead frames have the base end portions fixed to two opposite sides constituting the frame portion. The hydrogen sensor according to any one of claims 1 to 3, wherein a thickness of the nanowire is 100 nm or less. The hydrogen sensor according to any one of claims 1-4 that pre Symbol nanowire is characterized in that it is arranged at least one or more.

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