Optical hydrogen sensor based on magnesium-based hydrochromic film

Abstract

The invention provides an optical hydrogen sensor based on a magnesium-based hydrochromic film, which comprises a substrate and a shading shell, and the substrate is detachably connected with the shading shell; a sensing unit, a sensing unit, a display unit, a microprocessor, a light source and a power supply are arranged on the substrate; wherein the sensing unit is isolated from the sensing unit, the sensing unit is not in contact with hydrogen, and the sensing unit does not need to be heated or powered. According to the invention, the hydrogen concentration is monitored by utilizing a hydrogen-induced discoloration phenomenon, and the problems faced by the current hydrogen sensor are overcome by utilizing the intrinsic characteristics of high responsiveness, high selectivity, high safety and high durability of the magnesium-based hydrogen-induced discoloration film. The hydrogen sensor is low in cost, low in power consumption, low in operation difficulty and low in environment requirement, and has an important application prospect in the field of hydrogen sensing.

Description

Technical Field

[0001] The invention relates to the technical field of gas sensors, and in particular to an optical hydrogen sensor based on a magnesium-based hydrogen-induced chromic film. Background Art

[0002] Hydrogen energy is an ideal energy source for achieving the dual carbon goals, with advantages such as high combustion calorific value, no carbon emissions, and high energy conversion efficiency. However, hydrogen is colorless and odorless and is not easily detected by people. It is also flammable and explosive. The explosion limit in air is 4.0% to 75.6%. The ignition energy is low, and only 0.019mJ of heat is required to cause combustion. In addition, the molecules are small and are prone to leakage. The safety of hydrogen energy cannot be ignored. Therefore, a sensitive, accurate, safe and reliable hydrogen sensor is crucial to the entire hydrogen energy industry chain.

[0003] At present, the most mature hydrogen sensors are mainly catalytic combustion sensors, which are easily affected by electromagnetic interference, require heating and oxygen environment, respond to a variety of combustible gases, and are difficult to adapt to the actual application needs of complex industrial environments. Optical hydrogen sensors, by detecting light signals that do not rely on wire transmission, can achieve the effect of separating the reader from the sensing point, eliminating safety hazards; at the same time, optical sensors based on the principle of hydrogen color change have the advantages of intrinsic high selectivity and high sensitivity, and have broader application prospects.

[0004] The hydrogen-induced color phenomenon specifically refers to the transition of some metals, represented by magnesium, from a metallic state to a semiconductor state after hydrogenation, showing a change in macroscopic optical properties (transmittance / reflectivity). Magnesium has a high theoretical hydrogen storage capacity, is environmentally friendly and has abundant reserves. It can achieve a change in optical properties at room temperature under palladium catalysis. Based on this, magnesium-based hydrogen-induced color films have the characteristics of high responsiveness, high selectivity, high safety and high durability.

[0005] At present, the detection of hydrogen by optical hydrogen sensors relies on a complex optical path system. The equipment is large and mostly used in fixed positions, making it difficult to flexibly detect the source of hydrogen leakage. At the same time, the cost is relatively high, the energy consumption is large, the operation is complicated, and it is not conducive to long-term detection and rapid and timely response to emergencies. It cannot meet the actual needs of multi-site and large-scale use in scenarios such as hydrogen energy vehicles and hydrogen refueling stations.

[0006] Therefore, it is necessary to utilize the advantages of the intrinsic high selectivity and high sensitivity of magnesium-based hydrogen chromic films to develop a low-cost, low-power portable optical hydrogen sensor suitable for different environmental requirements. Summary of the invention

[0007] In view of the shortcomings of the prior art, the purpose of the present invention is to provide an optical hydrogen sensor based on a magnesium-based hydrogen-induced chromic film to solve the problems that the selectivity and sensitivity of catalytic combustion hydrogen sensors under the prior art conditions are low and the existing optical hydrogen sensor equipment is complex and costly.

[0008] The objective of the present invention is achieved through the following technical solutions:

[0009] In a first aspect, the present invention provides an optical hydrogen sensor, comprising a substrate and a light shielding shell, wherein the substrate and the light shielding shell are detachably connected; a sensitive unit, a sensor unit, a display unit, a microprocessor, a light source, and a power supply are arranged on the substrate;

[0010] The sensitive unit is arranged between the light source and the sensor unit, and the sensor unit is used to collect the light signal passing through the sensitive unit;

[0011] One end of the microprocessor is electrically connected to the sensor unit, and the other end is electrically connected to the display unit; the microprocessor is used to convert the optical signal input by the sensor unit into a digital signal and display it through the display unit;

[0012] The power supply is electrically connected to the light source, the display unit, and the microprocessor respectively;

[0013] A display window and an air inlet are arranged above the light-shielding housing, and the display window is located above the display unit;

[0014] A partition is also provided between the sensitive unit and the sensing unit, and the partition is provided in parallel with the sensitive unit;

[0015] The sensitive unit is connected to the substrate and the light-shielding shell to form a first closed cavity, and the power supply and the light source are located in the first closed cavity; the partition is connected to the substrate and the light-shielding shell to form a second closed cavity, and the sensor unit, the display unit and the microprocessor are located in the first closed cavity; a gas test chamber is formed between the sensitive unit and the partition, and the gas test chamber is connected to the air inlet, so that the gas in the external environment can enter the gas test chamber.

[0016] As a preferred solution, the sensitive unit is a magnesium-based hydrogen-induced chromic film.

[0017] As a preferred embodiment, the magnesium-based hydrogen-induced chromic film comprises an FC protective layer, a Pd catalyst layer, a Mg-X hydrogen-sensitive layer, and a substrate layer arranged in sequence;

[0018] As a preferred embodiment, in the Mg-X hydrogen sensitive layer, X is at least one of rare earth, transition metal or transition metal oxide; further preferably, X is at least one of scandium, yttrium, gadolinium, titanium, nickel, molybdenum, niobium, ruthenium, zirconium, lanthanum or their oxides; most preferably, X is scandium (Sc).

[0019] As a preferred solution, the substrate layer is selected from any one of a quartz glass layer, an optical fiber layer, a conductive glass layer, an organic glass layer, and a flexible glass layer.

[0020] As a preferred solution, the thickness of the FC protective layer is 30-150 nm, the thickness of the Pd catalytic layer is 3-7 nm, and the thickness of the Mg-X hydrogen sensitive layer is 10-80 nm.

[0021] As a preferred solution, one end of the base layer of the magnesium-based hydrogen-chromic film is close to the light source, and one end of the FC protective layer is far away from the light source.

[0022] As a preferred solution, the sensitive unit is a magnesium-based hydrogen-induced chromic film that has been subjected to hydrogen cycle stabilization treatment. The steps of the hydrogen cycle stabilization treatment are: at the same hydrogen concentration, the magnesium-based hydrogen-induced chromic film is subjected to multiple cycles of hydrogen absorption and desorption tests until the transmittance of the magnesium-based hydrogen-induced chromic film tends to be stable. The use of a magnesium-based hydrogen-induced chromic film that has been subjected to hydrogen cycle stabilization treatment can further improve the accuracy of the detection results.

[0023] As a preferred solution, the light source is a monochromatic LED lamp, more preferably a 520nm monochromatic LED lamp.

[0024] As a preferred solution, the connection line between the light source and the sensing unit (ie, the light path) is perpendicular to the sensing unit.

[0025] As a preferred solution, the sensing unit is a photoresistor or a photodetector.

[0026] As a preferred solution, the distance between the light source and the sensitive unit is 5 to 20 mm, and the distance between the sensitive unit and the sensing unit is 5 to 10 mm.

[0027] As a preferred solution, the partition is a transparent partition.

[0028] As a preferred solution, different types of microprocessors are selected according to actual working conditions such as detection standards, component layout, etc. Since the selected microprocessors are universal parts, they have strong compatibility, are easy to repair, update and expand functions, and are low in cost.

[0029] As a preferred solution, the substrate is a circuit board.

[0030] As a preferred solution, a switch is provided at the bottom of the substrate for turning on and off the optical hydrogen sensor.

[0031] As a preferred solution, interfaces are also provided at both ends of the substrate for connecting to external devices.

[0032] In a first aspect, the present invention provides a method for testing hydrogen concentration based on the aforementioned optical hydrogen sensor, comprising the following steps:

[0033] S1. Calibration of the relationship between hydrogen concentration, light transmittance and light signal simulation value: Place the optical hydrogen sensor in a closed space, introduce hydrogen with different concentration gradients, measure the light signal simulation value and transmittance of the sensitive unit at different hydrogen concentrations, and then obtain the fitting curve of the logarithm of hydrogen concentration lgH% and the light signal simulation value and transmittance;

[0034] S2. Place the calibrated optical hydrogen sensor into the space to be measured, turn on the switch, and then measure the hydrogen concentration of the space to be measured.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] 1. The optical hydrogen sensor designed with magnesium-based composite film as the sensitive unit of the present invention has low cost, small size and is easy to carry; and the sensitive unit can be replaced independently, further reducing maintenance costs.

[0037] 2. The optical hydrogen sensor of the present invention has a sealing design formed by the sensitive unit and the partition, so that each charged module does not come into direct contact with hydrogen; and the sensitive unit does not need to be heated or powered, there is no risk of ignition, and it is safe and reliable.

[0038] 3. The present invention further makes the prepared optical hydrogen sensor have the characteristics of high precision, sensitive response and resistance to interference from foreign gases through the reasonable selection and layout of the light source, sensitive unit and sensor unit.

[0039] 4. The optical hydrogen sensor of the present invention can also change the transmittance or reflectance measurement mode according to actual needs, which is convenient and fast, easy to operate, and suitable for various occasions. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Other features, objects and advantages of the present invention will become more apparent from the detailed description of non-limiting embodiments made with reference to the following drawings:

[0041] Figure 1 The structure and test principle diagram of the sensitive unit used in the optical hydrogen sensor of the present invention;

[0042] Figure 2 A schematic diagram of a transmittance curve of the hydrogen absorption process of the sensitive unit used in the present invention;

[0043] Figure 3 This is a diagram showing the internal structure of an optical hydrogen sensor according to an embodiment of the present invention;

[0044] Figure 4 It is a front view of the optical hydrogen sensor in the embodiment of the present invention;

[0045] Figure 5A fitting curve of the logarithm of hydrogen concentration lgH% and transmittance T% for hydrogen concentration calibration of the optical hydrogen sensor of the present invention;

[0046] Figure 6 for Figure 5 A fitting curve of the logarithmic value of hydrogen concentration lgH% and the light signal simulation value A for hydrogen concentration calibration of the optical hydrogen sensor of the present invention;

[0047] Corresponding names of the figure marks: 1-substrate; 2-light-shielding shell; 3-power supply; 4-light source; 5-sensitive unit; 6-sensing unit; 7-microprocessor; 8-display unit; 9-partition; 10-interface; 11-display window; 12-air inlet. DETAILED DESCRIPTION

[0048] Unless otherwise defined, technical or scientific terms used in the present specification and claims shall have the common meanings understood by persons having ordinary skills in the technical field to which the invention belongs.

[0049] All numerical values ​​from the lowest value to the highest value listed in this article refer to all numerical values ​​obtained by increments of one unit between the lowest value and the highest value when the difference between the lowest value and the highest value is more than two units.

[0050] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the invention.

[0051] In addition, the terms "first", "second", etc. are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first", "second", etc. may explicitly or implicitly include one or more of the feature. In the description of the invention, unless otherwise specified, "plurality" means two or more.

[0052] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood by specific circumstances.

[0053] The present invention is described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those of ordinary skill in the art, several variations and improvements may be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

[0054] Example

[0055] This embodiment relates to an optical hydrogen sensor based on a magnesium-based hydrogen-chromic film, such as Figure 3-Figure 4 As shown. The optical hydrogen sensor comprises a substrate 1 and a light shielding shell 2, and the substrate 1 and the light shielding shell 2 are detachably connected; specifically, the connection and separation of the substrate 1 and the light shielding shell 2 can be achieved by providing a U-shaped groove at the bottom of the light shielding shell 2 and providing a protrusion on the substrate 1 that is engaged with the U-shaped groove. With this design, the internal structural units can be replaced, such as the replacement of the sensitive unit 5 described below, the replacement of the light source 4 and the power supply 3, and the replacement of the chip in the microprocessor 7.

[0056] The substrate 1 is a circuit board, on which a light source 3, a power source 4, a sensitive unit 5, a sensor unit 6, a microprocessor 7, and a display unit 8 are arranged.

[0057] Wherein, the sensitive unit 5 is a magnesium-based hydrogen-induced chromic film, which can produce changes in optical properties (transmittance, reflectivity, etc.) according to changes in the hydrogen concentration in the environment, causing changes in light signals. The magnesium-based hydrogen-induced chromic film includes an FC protective layer, a Pd catalytic layer, a Mg-X hydrogen-sensitive layer, and a base layer arranged in sequence; in the Mg-X hydrogen-sensitive layer, X is scandium; the base layer is selected from any one of a quartz glass layer, an optical fiber layer, a conductive glass layer, an organic glass layer, and a flexible glass layer; the thickness of the FC protective layer is 30 to 150 nm, the thickness of the Pd catalytic layer is 3 to 7 nm, and the thickness of the Mg-X hydrogen-sensitive layer is 10 to 80 nm. In specific implementation, the transmittance / reflectivity can be selected as the detection signal according to the needs of the actual environment, and the corresponding Mg-X hydrogen-sensitive layer material can be selected.

[0058] In a specific embodiment, the magnesium-based hydrogen-induced chromic film can be prepared by magnetron sputtering and co-sputtering. For example, when preparing a magnesium-based hydrogen-induced chromic film in which X in the Mg-X hydrogen-sensitive layer is scandium, reference can be made to the preparation method of the fluorocarbon / palladium / magnesium-scandium hydrogen-induced chromic film in patent document CN113215544A. The entire process is controlled by a preset program, is simple to operate, has good stability, uniform film layer, good repeatability, and is convenient for mass production.

[0059] In a specific embodiment, the magnesium-based hydrogen-induced chromic film used is a CF / Pd / Mg-Sc film (including an FC protective layer, a Pd catalyst layer, a Mg-Sc hydrogen-sensitive layer, and quartz glass arranged in sequence), which can be prepared by the following method:

[0060] (1) Soaking the quartz glass (as the substrate) in the prepared cleaning solution for 15 minutes and then rinsing the quartz glass with deionized water for 1 minute; the cleaning solution is a mixed solution of concentrated sulfuric acid and hydrogen peroxide in a ratio of 3:1; placing the cleaned quartz glass in a magnetron sputtering reaction chamber, and turning on the vacuum system to evacuate until the background vacuum degree is 3×10 -4 Pa.

[0061] (2) Heat the quartz glass to a temperature of 20-25°C, introduce working gas A (argon), and maintain a pressure of 0.4-0.6 Pa. After the pressure stabilizes, turn on the power of the palladium, magnesium, and scandium targets, close the baffles in front of each target, and pre-sputter and clean the targets for 25 minutes. Then set the co-sputtering process program, the sputtering power of the magnesium and scandium targets is 80W and 100W respectively, the co-sputtering time is 200s, and the magnesium-scandium film is deposited, with a film thickness of 40nm.

[0062] (3) After the deposition is completed, the sputtering process program of the palladium catalyst layer is loaded while the vacuum degree is maintained at 0.5 Pa, and the sputtering power of the palladium target is adjusted to 40 W, the sputtering time is 14 s, and the film thickness is 5 nm. After the palladium film growth is completed, the power supply of all target materials is turned off, and the sample is continued to be purged with working gas A for 1 min, and then the sample is taken out to obtain a thin film with a composition of Pd / Mg-Sc.

[0063] (4) Place the Pd / Mg-Sc film in a reactive ion vapor deposition machine, set the process parameters of the fluorocarbon film to be 5Pa of working gas pressure, 40sccm of gas B flow, 600W of gas excitation power, and 15.6s of deposition time. Introduce working gas B (C4F8), load the process program, and deposit a fluorocarbon film with a film thickness of 30nm. After completion, take out the sample and obtain a film with a composition of CF / Pd / Mg-Sc. The structure and detection principle are shown in Figure 1 shown.

[0064] (5) The transmittance curve of the hydrogen absorption process of the CF / Pd / Mg-Sc film obtained by the test is shown in the figure. Figure 2 As shown by Figure 2 It can be seen that the hydrogen absorption reaction time of CF / Pd / Mg-Sc film is t 90 About 8 seconds.

[0065] In a variation, in order to further improve the accuracy, the step of subjecting the CF / Pd / Mg-Sc film obtained in the aforementioned step (5) to a hydrogen cycle stabilization treatment is also included. The specific operation is: at the same hydrogen concentration, the CF / Pd / Mg-Sc film is subjected to multiple cycles of hydrogen absorption and desorption tests until the transmittance of the CF / Pd / Mg-Sc film tends to be stable.

[0066] The light source 4 is used to provide a stable light signal required for the test. Specifically, a monochromatic LED lamp with a wavelength corresponding to the maximum response interval can be selected according to the different materials of the Mg-X hydrogen sensitive layer in the sensitive unit 5. Further, a 520nm monochromatic LED lamp can be preferably used, which has the advantages of stable luminous wavelength, low energy consumption, and less heat generation, and is suitable for long-term and stable detection of hydrogen concentration. In a specific embodiment, the light source used is an LED light emitting diode with a wavelength of 520nm.

[0067] The sensing unit 6 is used to detect the optical signal after passing through the sensitive unit 5 . Specifically, a photoresistor or a photodetector with corresponding parameters can be selected as the sensing unit 6 according to the different materials of the Mg—X hydrogen sensitive layer in the sensitive unit 5 .

[0068] Furthermore, the sensitive unit 5 is arranged between the light source 4 and the sensor unit 6, and is used to collect the light signal passing through the sensitive unit 5, and a partition 9 is also arranged between the sensitive unit 5 and the sensor unit 6. The partition 9 is a transparent partition and does not affect the transmission of the light signal. The connection line between the light source 4 and the sensor unit 6 is perpendicular to the sensitive unit 5, and the transparent partition is arranged in parallel with the sensitive unit 5.

[0069] In a specific implementation, the distance between the light source 4 and the sensitive unit 5 is 5 to 20 mm, and the distance between the sensitive unit 5 and the sensing unit 6 is 5 to 10 mm. This layout can ensure the stability, accuracy and sensitivity of signal transmission.

[0070] One end of the microprocessor 7 is electrically connected to the sensor unit 6, and the other end is electrically connected to the display unit 8; the microprocessor 7 is used to convert the optical signal input by the sensor unit 6 into a digital signal, and display it through the display unit 8. Specifically, different types of microprocessors 7 can be selected according to actual working conditions such as detection standards and component layout, and the present invention does not make any special limitation.

[0071] The display unit 8 can display the hydrogen concentration of the test environment according to the output result of the microprocessor 7 .

[0072] The power supply 3 is electrically connected to the light source 4, the sensor unit 6, the microprocessor 7, and the display unit 8, and is used to supply power to each component, and can be adjusted according to actual use conditions. In a specific embodiment, the power supply 3 is a DC power supply.

[0073] A display window 11 and an air inlet 12 are provided above the light shielding housing 2. The display window 11 is located above the display unit 8 and is infinitely close to the display screen of the display unit 8. The size of the display window 11 is consistent with the size of the display screen of the display unit 8. The material of the display window 11 is a transparent material. The data displayed on the display screen can be read through the display window 11, and the external ambient light source will not interfere with the inside of the hydrogen sensor.

[0074] In a specific embodiment, the sensitive unit 5 is connected with the substrate 1 and the light-shielding shell 2 to form a first closed cavity, and the power supply 3 and the light source 4 are located in the first closed cavity; the partition 9 is connected with the substrate 1 and the light-shielding shell 2 to form a second closed cavity, and the sensor unit 6, the display unit 8 and the microprocessor 7 are located in the first closed cavity; a gas test chamber is formed between the sensitive unit 5 and the partition 9, and the gas test chamber is connected with the air inlet 12, so that the gas of the external environment can enter the gas test chamber, thereby realizing the test of the hydrogen concentration in the gas of the external environment.

[0075] In a specific embodiment, the light shielding shell 2 is a black light shielding shell, which is used to eliminate background light and prevent dust interference. By covering the light source 4 and the sensor unit 6, the interference of the external environment light source and various internal reflected lights is removed, thereby improving the detection accuracy.

[0076] In a specific embodiment, a switch is also provided at the bottom of the substrate 1 for turning on and off the optical hydrogen sensor.

[0077] In a variation, at least one interface 10 is further provided at both ends of the substrate 1 for connecting an external device, and the type of the interface 10 is not particularly limited. In a specific embodiment, a first interface and a second interface are respectively provided at both ends of the substrate 1.

[0078] In a variation, an alarm device may be provided on the substrate to respond and sound an alarm when the hydrogen concentration detection value reaches a threshold value.

[0079] In a specific embodiment, a method for testing hydrogen concentration using an optical hydrogen sensor based on a magnesium-based hydrogen-chromic film is also provided, and the specific steps are as follows:

[0080] Calibration of hydrogen concentration: Place the optical hydrogen sensor in a closed space, turn on the switch, and introduce 0.1% volume fraction hydrogen. The measured light signal analog value output by the display unit of the optical hydrogen sensor is 1094, and the transmittance of the sensitive unit is 17.9%. Gradually increase the hydrogen concentration to 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, and 4%, and measure the corresponding light signal analog value and transmittance, so as to obtain the fitting curve of the logarithm of hydrogen concentration lgH% and transmittance T% as shown below: Figure 5 As shown in the figure, the fitting curve of the logarithm of hydrogen concentration lgH% and the light signal simulation value A is as follows Figure 6 As shown, the hydrogen concentration is calibrated;

[0081] Detection: Place the optical hydrogen sensor calibrated with hydrogen concentration into the test environment, turn on the switch, and the hydrogen concentration of the test environment can be measured. The minimum detection limit is less than 0.1%.

[0082] In a variation, in the hydrogen concentration testing method, in the hydrogen concentration calibration step, the hydrogen concentration can be calibrated by measuring the reflectivity of each hydrogen concentration instead of the transmittance to obtain a fitting curve of the logarithm of the hydrogen concentration lgH% and the reflectivity.

[0083] The present invention utilizes the hydrogen-induced color change phenomenon to realize the monitoring of hydrogen concentration, and utilizes the intrinsic high responsiveness, high selectivity, high safety, and high durability of the magnesium-based hydrogen-induced color change film to overcome the problems faced by the current hydrogen sensor. In addition, the present invention has low cost, low power consumption, low operating difficulty, and low environmental requirements, and has important application prospects in the field of hydrogen sensing.

[0084] The above description of the embodiments is to facilitate the understanding and use of the invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the scope of protection of the present invention.

Claims

1. An optical hydrogen sensor, characterized in that: It includes a substrate and a light shielding shell, and the substrate and the light shielding shell are detachably connected; the substrate is provided with a sensitive unit, a sensor unit, a display unit, a microprocessor, a light source, and a power supply; The sensitive unit is arranged between the light source and the sensor unit, and the sensor unit is used to collect the light signal passing through the sensitive unit; One end of the microprocessor is electrically connected to the sensor unit, and the other end is electrically connected to the display unit; the microprocessor is used to convert the optical signal input by the sensor unit into a digital signal and display it through the display unit; The power supply is electrically connected to the light source, the display unit, and the microprocessor respectively; A display window and an air inlet are arranged above the light-shielding housing, and the display window is located above the display unit; A partition is also provided between the sensitive unit and the sensing unit, and the partition is provided in parallel with the sensitive unit; The sensitive unit is connected to the substrate and the light-shielding shell to form a first closed cavity, and the power supply and the light source are located in the first closed cavity; the partition is connected to the substrate and the light-shielding shell to form a second closed cavity, and the sensor unit, the display unit and the microprocessor are located in the first closed cavity; a gas test chamber is formed between the sensitive unit and the partition, and the gas test chamber is connected to the air inlet, so that the gas in the external environment can enter the gas test chamber.

2. The optical hydrogen sensor according to claim 1, characterized in that: The sensitive unit is a magnesium-based hydrogen-induced chromic film.

3. The optical hydrogen sensor according to claim 2, characterized in that: The magnesium-based hydrogen-induced chromic film comprises an FC protective layer, a Pd catalytic layer, a Mg-X hydrogen-sensitive layer and a substrate layer which are arranged in sequence.

4. The optical hydrogen sensor according to claim 3, characterized in that: in, In the Mg-X hydrogen sensitive layer, X is at least one of rare earth, transition metal or transition metal oxide; The substrate layer is selected from any one of a quartz glass layer, an optical fiber layer, a conductive glass layer, an organic glass layer, and a flexible glass layer; The thickness of the FC protective layer is 30-150 nm, the thickness of the Pd catalytic layer is 3-7 nm, and the thickness of the Mg-X hydrogen sensitive layer is 10-80 nm.

5. The optical hydrogen sensor according to claim 3 or 4, characterized in that: One end of the base layer of the magnesium-based hydrogen-chromic film is close to the light source, and one end of the FC protective layer is far away from the light source.

6. The optical hydrogen sensor according to claim 3 or 4, characterized in that: The sensitive unit is a magnesium-based hydrogen-induced chromic film that has been subjected to hydrogen cycle stabilization treatment.

7. The optical hydrogen sensor according to claim 1, characterized in that: The light source is a monochromatic LED lamp.

8. The optical hydrogen sensor according to claim 1, characterized in that: The connecting line between the light source and the sensing unit is perpendicular to the sensing unit; The distance between the light source and the sensitive unit is 5 to 20 mm, and the distance between the sensitive unit and the sensing unit is 5 to 10 mm.

9. The optical hydrogen sensor according to claim 1, characterized in that: The partition is a transparent partition; A switch is provided at the bottom of the substrate for turning on and off the optical hydrogen sensor; At least one interface is also provided at both ends of the substrate for connecting to external devices.

10. A method for testing hydrogen concentration based on the optical hydrogen sensor according to any one of claims 1 to 9, characterized in that: The following steps are involved: S1. Calibration of hydrogen concentration: Place the optical hydrogen sensor in a closed space, turn on the switch, and introduce hydrogen with different concentration gradients. Measure the optical signal simulation values ​​of different hydrogen concentrations and the transmittance or reflectance of the sensitive unit. Then, obtain the fitting curve of the logarithm lgH% of the hydrogen concentration and the optical signal simulation value and the transmittance or reflectance, so as to calibrate the hydrogen concentration. S2. Detection: Place the optical hydrogen sensor calibrated with hydrogen concentration into the test environment, turn on the switch, and then the hydrogen concentration of the test environment can be measured.

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