Method for detecting hydrogen gas and hydrogen gas detector

Abstract

To provide a method for detecting a hydrogen gas and a detector for detecting a hydrogen gas on the basis of a whispering gallery mode (WGM) using a microsphere, the method and the detector detecting a hydrogen gas in real time at normal temperatures rapidly and sensitively.SOLUTION: The method for detecting a hydrogen gas and a detector for detecting a hydrogen gas irradiate light 9 from the back surface side of a substrate 10 to a microsphere 1 arranged on a substrate 10, resonate a whispering gallery mode excited in the surface of the microsphere 1 by evanescent light 11 seeping from the front surface side of the substrate 10, detect a resonance peak wavelength of scattering light emitted from the surface of the microsphere 1, and detect a hydrogen gas on the basis of change of the resonance peak wavelength under the presence of the hydrogen gas and under the absence of the hydrogen gas.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a method and apparatus for detecting hydrogen gas, and more particularly to a method and apparatus for detecting hydrogen gas based on whispering gallery mode (WGM) using a single microsphere. [Background technology]

[0002] In order to use renewable energy as a primary power source, it is necessary to solve the problems of cost, grid constraints, and adjustment capacity. Under these circumstances, Power To Gas (P2G), which converts surplus electricity into hydrogen for storage and use, has attracted attention, and demonstration projects are underway to put it into practical use. However, hydrogen gas is prone to diffusion and explosion, so there is a need to ensure safety during work and quickly detect gas leaks.

[0003] Research and development is being conducted into catalytic combustion, semiconductor, optical and other methods of rapid hydrogen gas detection. Among these, optical detection methods, which can detect a wide range of hydrogen explosion concentrations (4-74%), are being developed because of their superior speed and safety at room temperature (see, for example, Patent Documents 1 and 2).

[0004] Patent Document 1 discloses a method for detecting hydrogen gas leakage using a gasochromic metal thin film that absorbs hydrogen atoms and changes light reflection upon reaction with hydrogen gas.

[0005] Patent Document 2 discloses a method for measuring the gas concentration by irradiating a semiconductor laser onto the gas to be measured and detecting the Raman scattered light.

[0006] However, these detection methods and testing devices require the replacement of thin films due to deterioration of the sensor part and the adjustment of measuring equipment, making it difficult to obtain test results while keeping running costs down.

[0007] On the other hand, a technology has been developed that utilizes an optical mode in which a probe beam is injected into a single resonator and circulated. This optical resonant mode or resonance is called a whispering gallery mode (WGM) or a shape-dependent resonance (MDR), and occurs when the light injected as a probe beam is totally reflected and confined at the boundary surface of the resonator.

[0008] For example, because WGM is highly sensitive to surface conditions, it is used in biosensors in which a binding partner that binds to a target analyte is immobilized on the surface of a microsphere and the profile peak of WGM is detected (see, for example, Patent Documents 3 and 4). [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Publication No. 3192325 [Patent Document 2] JP 2011-158307 A [Patent Document 3] JP 2012-137490 A [Patent Document 4] Special Publication No. 2012-509070 Summary of the Invention [Problem to be solved by the invention]

[0010] In order to prevent gas explosions at sites where hydrogen is handled, a method for detecting hydrogen gas quickly and with high accuracy is required. In addition, to ensure safety during work, it is desirable to detect hydrogen gas in real time at room temperature.

[0011] An object of the present invention is to provide a hydrogen gas detection method and detection device based on whispering gallery mode (WGM) using microspheres, which can detect hydrogen gas quickly, with high sensitivity, and in real time at room temperature. [Means for solving the problem]

[0012] As a result of intensive research aimed at solving the above problems, the present inventors have found a method for detecting hydrogen gas based on a whispering gallery mode using a single microsphere. That is, the inventors have discovered that hydrogen gas can be detected based on the change in the resonance peak wavelength in the presence and absence of hydrogen gas by irradiating light from the back side of a microsphere placed on a substrate and resonating the whispering gallery mode excited on the surface of the microsphere by evanescent light seeping out from the front side of the substrate, thereby detecting the resonance peak wavelength of the scattered light emitted from the surface of the microsphere, and thus completing the present invention.

[0013] That is, the present invention is as follows. [1] A method for detecting hydrogen gas, comprising the steps of: irradiating a microsphere placed on a substrate with light from the back side of the substrate; resonating whispering gallery modes excited on the surface of the microsphere by evanescent light seeping out from the front side of the substrate; detecting the resonance peak wavelength of scattered light emitted from the surface of the microsphere; and detecting hydrogen gas based on the change in the resonance peak wavelength when hydrogen gas is present and when it is not. [2] The method for detecting hydrogen gas according to [1] above, wherein a portion of the surface of the microsphere is made of a material that occludes hydrogen gas. [3] The method for detecting hydrogen gas according to [2] above, wherein the material capable of absorbing hydrogen gas is any material selected from the group consisting of palladium, niobium, titanium, tungsten, nickel and vanadium. [4] The method for detecting hydrogen gas according to any one of the above [1] to [3], wherein the microspheres have pores on the surface thereof capable of retaining hydrogen gas. [5] The method for detecting hydrogen gas according to [4] above, wherein the microspheres are made of SiO2.

[0014] [6] Microspheres disposed on a substrate housed within a casing; a light source that irradiates the back surface of the substrate with light via an objective lens for excitation that can condense irradiation light to a diameter equal to or smaller than the diameter of the microsphere and generate evanescent light; a spectrometer for detecting a resonance peak wavelength of a whispering gallery mode excited on the surface of the microsphere; A hydrogen gas detection device comprising: [7] The hydrogen gas detection device according to [6] above, wherein a portion of the surface of the microsphere is made of a material that occludes hydrogen gas. [8] The hydrogen gas detection device according to [7] above, wherein the material capable of absorbing hydrogen gas is any material selected from the group consisting of palladium, niobium, titanium, tungsten, nickel and vanadium. [9] The hydrogen gas detecting device according to any one of the above [6] to [8], wherein the microspheres have pores on the surface thereof capable of retaining hydrogen gas.

[10] The hydrogen gas detection device according to [9] above, wherein the microspheres are made of SiO2. Effect of the Invention

[0015] According to the hydrogen gas detection method and detection device of the present invention, hydrogen gas can be detected quickly, highly sensitively, and in real time at room temperature. [Brief description of the drawings]

[0016] [Figure 1] FIG. 1 is an explanatory diagram of a microsphere according to one embodiment used in the hydrogen gas detection method and detection device of the present invention, in which (a) is a schematic diagram showing a state in which a thin film made of a material that occludes hydrogen gas is formed on a part of the surface, and (b) is a schematic diagram showing a state in which the thin film has occluded hydrogen gas and expanded. [Diagram 2] FIG. 1 is an explanatory diagram of a microsphere according to another embodiment used in the hydrogen gas detection method and detection device of the present invention, and is a schematic diagram showing a state in which hydrogen gas is retained (permeated) on the surface of a microsphere having pores capable of retaining hydrogen gas. [Diagram 3] 1 is a schematic diagram of a hydrogen gas detection device according to one embodiment of the present invention. [Figure 4] 1 is a schematic diagram illustrating a system according to one embodiment including a hydrogen gas detection device of the present invention. [Diagram 5] Graph (a) shows the resonant peak wavelength of the WGM before and after filling with hydrogen gas when a silica microsphere with a palladium thin film is used, and graph (b) shows the resonant peak wavelength of the WGM depending on the surface state of the microsphere calculated from the Mie scattering theory. [Figure 6] 1 shows the change in the resonant peak wavelength of the WGM when unmodified silica microspheres are filled with hydrogen gas of different concentrations, with the hydrogen gas of concentrations 3.92%, 9.83%, 30.00%, 50.30%, and 99.99% being shown. The white arrow in the figure indicates that the resonant peak wavelength of the WGM in air is taken as the reference and that the resonant peak wavelength shifts to the shorter wavelength side after filling with hydrogen gas. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] The hydrogen gas detection method of the present invention is characterized in that a microsphere placed on a substrate is irradiated with light from the back side of the substrate, a whispering gallery mode excited on the surface of the microsphere by evanescent light seeping out from the front side of the substrate is resonated, the resonance peak wavelength of scattered light emitted from the surface of the microsphere is detected, and hydrogen gas is detected based on the change in the resonance peak wavelength when hydrogen gas is present and when it is not present.

[0018] According to the hydrogen gas detection method of the present invention, hydrogen gas can be detected quickly, highly sensitively, and in real time at room temperature. That is, the presence or absence of hydrogen gas can be easily detected by using the change in the peak signal of the WGM. This ensures safety during work and enables rapid detection of gas leaks. In addition, the detection method of the present invention is highly safe because it does not require heating the sensor part. Furthermore, since hydrogen gas can be detected by using a single microsphere, a specified light source, and a spectroscope, hydrogen gas can be detected more efficiently and at a lower cost than conventional hydrogen gas sensors such as catalytic combustion type, semiconductor type, and optical type.

[0019] The hydrogen gas detection method of the present invention can be used in hydrogen production facilities, hydrogen storage facilities, hydrogen transport vehicles, hydrogen automobiles, fuel cell ships, and other sites where hydrogen is used.

[0020] The hydrogen gas detection method of the present invention can detect hydrogen at a concentration within the explosive concentration range (4 to 74%), and can also detect hydrogen at a concentration below the explosive concentration range. The detection method of the present invention can detect hydrogen gas at room temperature. However, this does not prevent the detection method from being used in environments other than room temperature.

[0021] [substrate] The substrate is a transparent plate-like member on which the microspheres are placed, and is not limited as long as it can cause evanescent light to seep out from the front side when light is irradiated from the back side. The thickness of the substrate is preferably 200 μm or less, and more preferably 50 to 170 μm. This makes it easy to focus on the microspheres even when the space between the excitation objective lens and the planar substrate is filled with immersion oil.

[0022] [Microsphere] The diameter of the microsphere is preferably 0.5 to 15 μm, and more preferably 1 to 10 μm. Moreover, it is preferable that the microsphere is transparent, and more preferably has high sphericity and a high refractive index. This makes it possible to more reliably confine light within the surface of the microsphere. Specific examples of materials constituting the microsphere include SiO2, PMMA, acrylic, polystyrene, etc., and SiO2 is particularly preferable.

[0023] It is preferable that a part of the surface of the microsphere is made of a material that absorbs hydrogen gas (hydrogen gas absorption material). If the entire surface of the microsphere is made of hydrogen gas absorption material, the light absorption at the microsphere surface is large, and the light circulating around the microsphere surface is attenuated, so that the WGM may not be excited. The hydrogen gas absorption material on the surface of the microsphere is present in 20 to 80% of the orbital plane of the light (WGM) circulating around the microsphere surface, and more preferably in 25 to 50%.

[0024] An embodiment in which a part of the surface of the microsphere is composed of a hydrogen gas storage material can be mentioned in which the surface of the microsphere composed of a material other than the hydrogen gas storage material is coated with the hydrogen gas storage material.Specific preferred embodiments include, for example, an embodiment in which the hydrogen gas storage material is present in a dot shape or a border shape on the surface of the microsphere composed of a material other than the hydrogen gas storage material.The coating thickness of the hydrogen gas storage material is, for example, preferably 10 to 40 nm, more preferably 15 to 30 nm.

[0025] (Hydrogen gas storage materials) The hydrogen gas storage material is not particularly limited as long as it specifically stores hydrogen gas by changing its expansion or refractive index, and examples of the hydrogen gas storage material include palladium, niobium, titanium, tungsten, nickel, vanadium, etc., with palladium being preferred.

[0026] (Hydrogen gas retention pores) A preferred embodiment of the microsphere has pores on its surface that can retain hydrogen gas. Also, it is preferred that the pores have hydroxyl groups (OH groups). Even if a part of the surface of a microsphere having such pores is not made of a material that occludes hydrogen gas (even if the microsphere is an unmodified microsphere), the microsphere can retain hydrogen gas on its surface, and can detect hydrogen gas by causing a change in the resonance peak wavelength.

[0027] As the microspheres having pores capable of retaining hydrogen gas, microspheres made of SiO2 can be mentioned. In particular, the microspheres of the present invention are preferably made of a material having pores capable of retaining hydrogen gas, and a part of the surface of the microspheres is coated with a material capable of occluding hydrogen gas.

[0028] Next, a hydrogen gas detection device that can be used in the above-mentioned hydrogen gas detection method will be described. The hydrogen gas detection device of the present invention is characterized by comprising a microsphere placed on a substrate contained within a casing, a light source that irradiates light from the back side of the substrate via an excitation objective lens that can focus the irradiated light to a diameter equal to or smaller than the diameter of the microsphere and generate evanescent light, and a spectrometer that detects the resonance peak wavelength of the whispering gallery mode excited on the surface of the microsphere.

[0029] According to the hydrogen gas detection device of the present invention, hydrogen gas can be detected quickly, highly sensitively, and in real time at room temperature. That is, the presence or absence of hydrogen gas can be easily detected by using the change in the peak signal of the WGM. This ensures safety during work and enables rapid detection of gas leaks. In addition, the detection device of the present invention is highly safe because it does not require heating the sensor part. Furthermore, since hydrogen gas can be detected by using a single microsphere, a specified light source, and a spectroscope, hydrogen gas can be detected more efficiently and at a lower cost than conventional hydrogen gas sensors such as catalytic combustion type, semiconductor type, and optical type.

[0030] The hydrogen gas detection device of the present invention can be used in hydrogen production facilities, hydrogen storage facilities, hydrogen transport vehicles, hydrogen automobiles, fuel cell ships, and other sites where hydrogen is used.

[0031] [Substrate and microspheres] The substrate and the microspheres are the same as those described in the hydrogen gas detection method above, and therefore will not be described.

[0032] [Excitation objective lens] The objective lens for excitation preferably has a large numerical aperture (NA), which makes the spot diameter of the incident light smaller than the diameter of the microsphere, preventing stray light from other than the microsphere from being detected and enabling detection with a high S / N ratio.

[0033] [Spectrometer] The resolution of the spectrometer is preferably 1 nm or less, which allows detection even if the resonance peak wavelength of the scattered light detected by the spectrometer is shifted to the longer wavelength side by about 2 to 4 nm.

[0034] Hereinafter, an embodiment for carrying out the present invention will be described with reference to the drawings, but the present invention is not limited to this embodiment.

[0035] Here, Fig. 1 is an explanatory diagram of a microsphere according to one embodiment used in the hydrogen gas detection method and detection device of the present invention, (a) is a schematic diagram showing a state in which a thin film made of a material that occludes hydrogen gas is formed on a part of the surface, and (b) is a schematic diagram showing a state in which the thin film occludes hydrogen gas and expands. Fig. 2 is an explanatory diagram of a microsphere according to another embodiment used in the hydrogen gas detection method and detection device of the present invention, and is a schematic diagram showing a state in which hydrogen gas is held (permeated) on the surface of a microsphere having pores that can hold hydrogen gas.

[0036] As shown in Fig. 1(a), the microsphere 1 used in the hydrogen gas detection method and detection device of the present invention is a silica microsphere having spherical properties as a microcavity resonator. The microsphere 1 has a thin palladium film 2 having a thickness of about 40 nm formed in the form of dots on its surface. The microsphere 1 is placed on a planar substrate.

[0037] As shown in Figure 1(b), when the microsphere 1 absorbs hydrogen gas, the refractive index changes due to the expanded palladium thin film 3, and the presence or absence of hydrogen gas can be determined (hydrogen gas detection) by detecting the periodic change in the resonance peak wavelength caused by the WGM.

[0038] When light incident on the back side of the planar substrate of microsphere 1 is totally reflected on the front side of the substrate, the evanescent light generated excites the surface of the microsphere, generating WGM, which confines and circulates the light within the surface. At this time, a spectrum with periodic resonance peak wavelengths due to WGM is detected from the scattered light emitted from the surface of microsphere 1. This resonance peak wavelength is highly sensitive to the diameter and refractive index of the microsphere, as well as the conditions around the microsphere, so the presence or absence of hydrogen gas can be detected based on the change in the resonance peak wavelength.

[0039] 2, the silica microspheres 1A according to another embodiment have pores 2A capable of retaining hydrogen gas 4. The pores 2A are provided in about half of the total volume, and their diameters are larger than the kinetic molecular diameter of hydrogen gas 4, which is 0.289 nm. Therefore, the hydrogen gas 4 penetrates the surface of the silica microspheres 1A and chemically bonds with the hydroxyl groups (OH groups) on the surface.

[0040] Next, a hydrogen gas detection device according to one embodiment of the present invention will be described below, with reference to Fig. 3, which is a schematic diagram of the hydrogen gas detection device according to one embodiment of the present invention. As shown in Figure 3, the hydrogen gas detection device of the present invention comprises a microsphere 1 arranged on a planar substrate 10 contained in a casing, an excitation light source 5 that irradiates light from the back side of substrate 10 via an excitation objective lens 8 that can focus the irradiated light to a diameter equal to or smaller than the diameter of microsphere 1 and generate evanescent light 11, and a spectrometer 18 that detects the resonance peak wavelength of the whispering gallery mode excited on the surface of microsphere 1.

[0041] The excitation light source 5 is a white light source, and the excitation direction of TE polarized light and TM polarized light is switched by a polarizer 6, and incident light 9 is irradiated onto an inverted excitation objective lens 8 by a reflecting mirror 7. The microsphere 1 is placed on a planar substrate 10 attached to the bottom surface of the dish. Since the incident light 9 is incident through the excitation objective lens 8 with a large numerical aperture (NA), the angle of the incident light 9 on the planar substrate 10 is equal to or greater than the total reflection angle, and evanescent light 11, which is a localized wave, is generated on the surface of the planar substrate 10. In order to fill the space between the excitation objective lens 8 and the planar substrate 10 with immersion oil 12 and to focus on the microsphere 1, it is preferable that the thickness of the planar substrate 10 is 170 μm or less.

[0042] In the hydrogen gas detector of the present invention, by using an excitation objective lens 8 having a large numerical aperture (NA), the spot diameter of the incident light 9 becomes equal to or smaller than the diameter of the microsphere 1, and stray light from other than the microsphere 1 is not detected, making it possible to detect with a high S / N ratio. In addition, by sealing with a sealing cover 13 using an O-ring and sealing tape, and filling with hydrogen gas 4 from a tube 14 inserted into the detection section, it becomes possible to detect a spectrum with high accuracy depending on the presence or absence of hydrogen gas 4. The scattered light from the microsphere 1 is collected by a detection lens 15 attached to the top, and can be evaluated by switching between observation with a CCD camera 17 and spectrum detection with a spectrometer 18 by an X-axis moving mirror 16. Note that the scattered light detected by the spectrometer 18 has a resonance peak wavelength shifted to the short wavelength side by about 2 to 4 nm due to the presence of hydrogen gas, so it is preferable to use a spectrometer 18 with a resolution of 1 nm or less.

[0043] 4 is a schematic diagram showing a system according to one embodiment including the hydrogen gas detection device of the present invention. Scattered light acquired from WGM light detection unit 19 (the hydrogen gas detection device shown in FIG. 3 without spectrometer 18) is guided through optical fiber 20 and detected by spectrometer 18. The optical signal converted by spectrometer 18 into an electrical signal is used by wavelength change detection unit 21 to calculate the amount of change in resonance peak wavelength, and leakage gas determination unit 22 can determine whether the target gas has been occluded on the surface of microsphere 1.

[0044] For example, when the wavelength resolution of the spectrometer 18 is set to 1 nm and the hydrogen gas 4 is detected by the leakage gas determination unit 22, the detection time is about 1 to 2 seconds. EXAMPLES

[0045] Using the above hydrogen gas detection device, a demonstration experiment of hydrogen gas detection was carried out. The details of the demonstration experiment will be explained in detail below.

[0046] (1) Hydrogen gas Hydrogen gas cassettes were used from Taiyo Nippon Sanso and GL Sciences. Nitrogen was used as the balance gas to adjust the hydrogen concentration (4% to 50%).

[0047] (2) Microsphere probe Using silica microspheres (manufactured by Micromod) with a diameter of 10 μm, a thin palladium film that specifically absorbs hydrogen gas was formed by powder plating (manufactured by Kiyokawa Plating Research Institute).

[0048] (3) Irradiation light A white light source (170-2100 nm) manufactured by Sigma Technology was used as the excitation light source. The TE or TM polarization direction was selected from random polarization by rotating a polarizer (Glan-Thompson prism) manufactured by Sigma Koki by 90°.

[0049] (4) Hydrogen gas filling and exhaust methods A fluororesin tube (Nissei Electric) was inserted into a glass base dish (Iwaki) on which the microspheres were placed, and hydrogen gas was filled from a gas cassette canister. Hydrogen gas was exhausted by stopping the gas cassette canister and releasing it into the atmosphere.

[0050] (5) Evaluation method for micro-ball probe The microsphere probe was placed on a planar substrate attached to the bottom surface of the glass base dish shown in Figure 3, and was sealed with a sealing lid using a nitrile rubber O-ring (Uxcell) and sealing tape (Three Bond). The microsphere was excited with a white light source, and the scattered light spectrum was detected in the wavelength range of 555 to 580 nm.

[0051] FIG. 5(a) is a graph showing the resonant peak wavelength of the WGM before and after filling with hydrogen gas when a silica microsphere with a palladium thin film is used, and FIG. 5(b) is a graph showing the resonant peak wavelength of the WGM depending on the surface condition of the microsphere calculated from the Mie scattering theory.

[0052] As shown in the graph in Figure 5(a), when hydrogen (concentration 99.99%) was filled into the microsphere while it was excited, the resonance peak wavelength of the WGM, which reflected the surface condition of the microsphere, was detected in the scattered light spectrum. In other words, filling with hydrogen gas shifted the wavelength by 3 to 4 nm to the shorter wavelength side.

[0053] In addition, the detected resonant peak wavelength can be fitted to the scattering cross section based on the Mie theory shown in the graph in Figure 5(b) to estimate the changes in the refractive index and thickness of the thin film. The diameter and refractive index of the silica microsphere 1 are 10 μm and 1.40, and the refractive indices of air and hydrogen are 1.000300 and 1.000139. When hydrogen is filled, the thickness of the thin palladium film 2 on the surface of the microsphere 1 expands by 10%, and the refractive index decreases, which is consistent with the change in the resonance peak wavelength of the WGM in Figure 5(a). Note that here, the calculations are based on the assumption that the thin palladium film 2 is fixed on the silica microsphere 1 as a single layer, the thickness of the palladium layer is 20 nm to 22 nm, and the refractive index is 1.40 to 1.0.

[0054] Figure 6 shows the change in the resonant peak wavelength of the WGM when unmodified silica microspheres are filled with hydrogen gas of different concentrations, with the hydrogen gas of concentrations 3.92%, 9.83%, 30.00%, 50.30%, and 99.99% being shown. The white arrow in the figure indicates that the resonant peak wavelength of the WGM in air is taken as the reference and that the resonant peak wavelength shifts to the shorter wavelength side after filling with hydrogen gas.

[0055] By changing the concentration by replacing five types of hydrogen gas cassette cans (concentrations of 3.92%, 9.83%, 30.00%, 50.30%, and 99.99%), it can be seen that the resonance peak wavelength shifts to the shorter wavelength side, making it possible to detect hydrogen within the explosive concentration range of hydrogen (4-74%). It can also be seen that the higher the hydrogen concentration, the greater the change in the resonance peak wavelength. Furthermore, when nitrogen gas is filled, there is almost no change in the resonance peak wavelength, less than 1 nm, indicating that this detection method is able to specifically detect hydrogen gas.

[0056] It was confirmed that the resonant peak wavelength of the silica microspheres with a thin palladium film and the unmodified silica microspheres returned to the position before hydrogen gas was charged when the charging was stopped, and the resonant peak wavelength shifted again to the shorter wavelength side when hydrogen gas was charged again, which means that the silica microspheres can be reused. [Industrial Applicability]

[0057] INDUSTRIAL APPLICABILITY The hydrogen gas detection method and detection device of the present invention can be used for detecting hydrogen gas in hydrogen production facilities and the like, and therefore are industrially useful. [Explanation of symbols]

[0058] 1 Microsphere 2 Palladium thin film 3. Expanded palladium thin film 4. Hydrogen 5. Excitation light source 6 Polarizer 7 Reflective Mirror 8 Excitation objective lens 9 Incident light 10 Planar substrate 11 Evanescent light 12. Immersion Oil 13 Sealing lid 14 Tube 15 Detection lens 16 X-axis moving mirror 17 CCD camera 18 Spectrometer 19 WGM light detector 20. Fiber Optic 21 Wavelength change detection unit 22 Gas leakage determination unit

Claims

1. A method for detecting hydrogen gas, comprising the steps of: irradiating a microsphere placed on a substrate with light from the back side of the substrate; resonating a whispering gallery mode excited on the surface of the microsphere by evanescent light seeping out from the front side of the substrate; detecting the resonance peak wavelength of scattered light emitted from the surface of the microsphere; and detecting hydrogen gas based on the change in the resonance peak wavelength when hydrogen gas is present and when it is not.

2. 2. The method for detecting hydrogen gas according to claim 1, wherein a part of the surface of said microspheres is made of a material that absorbs hydrogen gas.

3. 2. The method for detecting hydrogen gas according to claim 1, wherein the microspheres have pores on the surface thereof capable of retaining hydrogen gas.

4. 3. The method for detecting hydrogen gas according to claim 2, wherein the material capable of absorbing hydrogen gas is any material selected from the group consisting of palladium, niobium, titanium, tungsten, nickel and vanadium.

5. The microspheres are made of SiO ２ 4. The method for detecting hydrogen gas according to claim 3, further comprising:

6. Microspheres disposed on a substrate housed within a casing; a light source that irradiates the back surface of the substrate with light via an objective lens for excitation that can condense irradiation light to a diameter equal to or smaller than the diameter of the microsphere and generate evanescent light; a spectrometer for detecting a resonance peak wavelength of a whispering gallery mode excited on the surface of the microsphere; A hydrogen gas detection device comprising:

7. 7. The hydrogen gas detecting device according to claim 6, wherein a part of the surface of said microsphere is made of a material that absorbs hydrogen gas.

8. 7. The hydrogen gas detecting device according to claim 6, wherein the microspheres have pores on the surface thereof capable of retaining hydrogen gas.

9. 8. The hydrogen gas detecting device according to claim 7, wherein the material capable of absorbing hydrogen gas is any material selected from the group consisting of palladium, niobium, titanium, tungsten, nickel and vanadium.

10. The microspheres are made of SiO ２ 9. The hydrogen gas detection device according to claim 8, further comprising:

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