Hydrogen-sensitive colour-changing material and its use

Abstract

The application discloses a hydrogen-sensitive color-changing material and application thereof. The hydrogen-sensitive color-changing material is a kind of structural color material, which comprises at least one substrate layer, at least one color-changing layer and at least one catalytic layer arranged in layers; when the hydrogen-sensitive color-changing material is in contact with hydrogen, the catalytic layer can at least convert part of the hydrogen into active hydrogen atoms, wherein at least part of the active hydrogen atoms can react with at least one of the color-changing layers, so as to change the color of the hydrogen-sensitive color-changing material. The hydrogen-sensitive color-changing material provided by the application has physical structural color through the optical interference of multiple layers, has the advantages of not fading, environmental protection and being able to produce rich iridescent effects, and the excellent naked-eye visible color-changing effect can accurately indicate the leakage point when hydrogen leaks, the response time is relatively short, excellent color-changing indication effect can be produced, the material can be prepared through a relatively convenient deposition method, the time consumption is short, the process is simple, large-area controllable production can be easily realized, and no chemical pollutants are produced.

Description

Technical Field

[0001] This invention relates to the field of inorganic materials technology, and in particular to a hydrogen-sensitive color-changing material and its applications. Background Technology

[0002] Hydrogen is recognized globally as the cleanest fuel, but due to its wide explosion limit range, when the volume content of hydrogen in the air is between 4% and 75.6%, it will explode upon contact with an open flame. Furthermore, it is colorless and odorless, making leaks difficult to detect, which poses a significant safety hazard.

[0003] To improve the safety of hydrogen in production, use, storage, and transportation, it is crucial to install reliable hydrogen leak detection and alarm systems at hydrogen-using sites. This ensures that even if a leak occurs, it can be detected and addressed promptly. Currently, commonly used hydrogen detectors in industry employ hydrogen-sensitive elements primarily of electrochemical, thermal conductivity, thermoelectric effect, resistive, and optical types. Among these, optical hydrogen concentration detection generally operates on two principles: one is based on infrared absorption and light scattering technology, and the other is based on the reversible reaction of hydrogen with a specific substance, resulting in changes in physical parameters and optical properties. For example, hydrogen-sensitive reversible color-changing materials react with hydrogen, and the changes in optical properties are used to monitor and trigger alarms regarding hydrogen concentration.

[0004] Current hydrogen-sensitive reversible color-changing materials are multivalent oxides loaded with certain noble metals. Upon contact with hydrogen gas, the hydrogen molecules rapidly decompose into active H atoms, partially reducing the multivalent oxide and resulting in a color change. For example, patent application CN111662650A uses a binder (polysiloxane, reinforcing agent, crosslinking agent, and crosslinking catalyst) and a color-changing material (metal oxide and metal nanoparticles) mixed in a kneader to obtain a rubber compound. This compound is then extruded into thin strips to produce tape. The resulting tape can achieve three color changes: pale yellow-blue, dark brown-light brown, and light gray-blue. However, the color changes are relatively limited, and the color differences between dark brown-light brown and light gray-blue are not significant, posing a problem for naked-eye perception.

[0005] Patent CN112592708A uses WO3 and elemental metals (Fe, Pt, and Y) as active components loaded onto substrates such as Al2O3, TiO2, SiO2, molecular sieves, kaolin, bentonite, and diatomaceous earth. This requires a series of processes including impregnation, drying, reaction, calcination, mixing, settling, solid-liquid separation, drying, and calcination. The process is complex, involves many steps, is time-consuming, inefficient, and difficult to industrialize.

[0006] In summary, current technologies can only achieve a change from pale yellow to blue, with other color changes being indistinct and difficult to distinguish with the naked eye. The color range is limited, making it difficult to meet the current demand for hydrogen detection in various scenarios. Alternatively, they may have drawbacks such as being time-consuming, having complex procedures, causing environmental pollution, and lacking industrialization capabilities, making it difficult to meet the ever-increasing demand for hydrogen detection. Summary of the Invention

[0007] In view of the shortcomings of the prior art, the purpose of this invention is to provide a hydrogen-sensitive color-changing material and its application.

[0008] To achieve the aforementioned objectives, the technical solution adopted by this invention includes:

[0009] In a first aspect, the present invention provides a hydrogen-sensitive color-changing material, comprising at least one base layer, at least one color-changing layer and at least one catalyst layer stacked together; when the hydrogen-sensitive color-changing material comes into contact with hydrogen gas, the catalyst layer can convert at least a portion of the hydrogen gas into active hydrogen atoms, and the color-changing layer can be reduced by hydrogen atoms to change its color, thereby changing the color of the hydrogen-sensitive color-changing material.

[0010] Secondly, the present invention also provides a method for preparing a hydrogen-sensitive color-changing material, comprising:

[0011] The steps include providing a substrate; and sequentially forming a color-changing layer and a catalyst layer on the substrate.

[0012] In some preferred embodiments, the color-changing layer and the catalyst layer are formed by physical vapor deposition.

[0013] Furthermore, the color-changing layer and the catalyst layer are formed by magnetron sputtering.

[0014] Thirdly, the present invention also provides the use of the above-mentioned hydrogen-sensitive color-changing material in the preparation of gas detection materials or gas detection devices;

[0015] Furthermore, the specific uses include the preparation of detection materials or devices for one or more combinations of gases selected from hydrogen, methane, ethylene, acetylene, ammonia, hydrogen sulfide, and carbon monoxide.

[0016] Fourthly, the present invention also provides a gas detection method, comprising: contacting the gas to be detected with the aforementioned hydrogen-sensitive color-changing material, and determining whether the gas to be detected contains the gas to be detected by observing the color change of the hydrogen-sensitive color-changing material.

[0017] Fifthly, the present invention also provides a method of using a hydrogen-sensitive color-changing material, comprising:

[0018] The hydrogen-sensitive color-changing material is brought into contact with the gas to be detected, thereby changing the color of the hydrogen-sensitive color-changing material;

[0019] Furthermore, the hydrogen-sensitive color-changing material, after changing color, is brought into full contact with oxygen or oxygen-containing gas, thereby restoring the hydrogen-sensitive color-changing material to its initial color.

[0020] In the above technical solution, after contact with the gas to be detected, especially hydrogen, the protons react with the color-changing layer, causing the transition metal oxide in the color-changing layer to be reduced to metal hydride, which in turn causes the color of the color-changing layer to change, and thus the color of the entire hydrogen-sensitive color-changing material to change.

[0021] Based on the above technical solution, compared with the prior art, the beneficial effects of the present invention include at least the following:

[0022] The hydrogen-sensitive color-changing material provided by this invention obtains physical structural color through multi-layered optical interference. It has the advantages of being colorfast, environmentally friendly, and capable of producing an iridescent effect. It changes color significantly upon contact with hydrogen gas and has a short response time, thus exhibiting excellent hydrogen color-changing indication effect.

[0023] Furthermore, due to its colorful physical structural colors, the hydrogen-sensitive color-changing material provided by this invention has broad application prospects in display, decoration, anti-counterfeiting and other fields.

[0024] Furthermore, the hydrogen-sensitive color-changing material provided by this invention can be prepared by a relatively convenient deposition method, which is time-saving, streamlined, and does not generate a large amount of chemical pollutants. This is very beneficial for industrial applications and meets the increasing demand for hydrogen detection.

[0025] The above description is merely an overview of the technical solution of the present invention. In order to enable those skilled in the art to better understand the technical means of this application and to implement it in accordance with the contents of the specification, the preferred embodiments of the present invention are described below in conjunction with detailed drawings. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the overall structure of the hydrogen-sensitive color-changing material provided in a typical embodiment of the present invention;

[0027] Figure 2 This is a schematic diagram of the structure of the color-changing layer in a hydrogen-sensitive color-changing material provided in a typical embodiment of the present invention;

[0028] Figure 3 This is a photograph of a carbon nanotube film used as a substrate, provided in a typical embodiment of the present invention.

[0029] Figure 4 This is a photograph of a hydrogen-sensitive color-changing material provided in a typical embodiment of the present invention;

[0030] Figure 4 This is a photograph of the color-changing process of a hydrogen-sensitive color-changing material provided in a typical embodiment of the present invention;

[0031] Figure 6 This is a test graph showing the reflectance change of a hydrogen-sensitive color-changing material under different hydrogen concentrations, provided in a typical embodiment of the present invention.

[0032] Figure 7 This is a cyclic test chart of the reflectance change of a hydrogen-sensitive color-changing material provided in a typical embodiment of the present invention;

[0033] Figure 8 These are optical photographs of a series of different hydrogen-sensitive color-changing materials provided in a typical embodiment of the present invention;

[0034] Figure 9 These are photographs of the color-changing process of different hydrogen-sensitive color-changing materials provided in a typical embodiment of the present invention;

[0035] Figure 10 These are photographs of the reversible recovery process of different hydrogen-sensitive color-changing materials provided in a typical embodiment of the present invention;

[0036] Figure 11 This is a photograph of the color-changing process of a PET transparent substrate hydrogen-sensitive color-changing material provided in a typical embodiment of the present invention;

[0037] Figure 12 This is a photograph of the color-changing process of the hydrogen-sensitive color-changing material provided in a typical comparative case of the present invention;

[0038] Figure 13 This is a photograph of the color-changing process of the hydrogen-sensitive color-changing material provided in another typical comparative case of the present invention;

[0039] Figure 14a This is a color-changing photograph of the process of detecting gas cylinder leakage using a hydrogen-sensitive color-changing material, provided in a typical embodiment of the present invention.

[0040] Figure 14b This is a color-changing photograph of the process of detecting gas cylinder leakage using a hydrogen-sensitive color-changing material, provided in another typical embodiment of the present invention. Detailed Implementation

[0041] In view of the shortcomings of the prior art, the inventors of this invention, through long-term research and extensive practice, have proposed the technical solution of this invention. The following will further explain and illustrate the technical solution, its implementation process, and its principles.

[0042] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and therefore the scope of protection of the invention is not limited to the specific embodiments disclosed below.

[0043] The purpose of this invention is to provide a method for preparing hydrogen-sensitive color-changing materials that can achieve rich color changes and are clearly visible to the naked eye, and it has advantages that are conducive to industrialization.

[0044] See Figure 1 This invention provides a hydrogen-sensitive color-changing material, comprising at least one base layer, at least one color-changing layer, and at least one catalyst layer stacked together. When the hydrogen-sensitive color-changing material comes into contact with hydrogen gas, the catalyst layer can convert at least a portion of the hydrogen gas into active hydrogen atoms, and the color-changing layer can be reduced by hydrogen atoms to change its color, thereby changing the color of the hydrogen-sensitive color-changing material.

[0045] Specifically, this invention provides a multi-color-changing hydrogen-sensitive color-changing material, comprising a substrate layer, a color-changing layer, and a catalyst layer; the substrate may be, for example, carbon materials (including one-dimensional carbon nanotube fibers, two-dimensional carbon nanotube films, graphene films, carbon fibers, carbon fiber cloth, etc.), glass, plexiglass, plastic products, fibers, fabrics, wood panels, ceramics, or metal alloys, etc.; the color-changing layer is a metal or transition metal oxide layer structure, which can produce optical interference to display multiple colors.

[0046] The different colors of the hydrogen-sensitive color-changing material can be achieved by selecting one or a combination of different metal materials, different transition metal oxide materials, or transition metal oxide layers of different thicknesses.

[0047] In some embodiments, the substrate is made of any one or more of the following materials: carbon materials, inorganic glass, plexiglass, plastic, fiber, fabric, wood, ceramic, and metal; wherein, the substrate can be a breathable material or an impermeable material, but is preferably a breathable material, and the breathable material includes any one or more of the following materials: breathable carbon materials, breathable fabrics, breathable plastic films, etc.

[0048] In some embodiments, the substrate is selected from carbon materials.

[0049] In some embodiments, the carbon material includes any one or a combination of two or more of carbon nanotube fibers, carbon nanotube films, graphene films, carbon fibers, and carbon fiber fabrics.

[0050] In some embodiments, the substrate is selected from carbon nanotube films.

[0051] Specifically, regarding the choice of substrate, flexible or rigid substrates, transparent or opaque substrates, and breathable or impermeable substrates can all achieve the hydrogen-sensitive color-changing effect of this invention. However, through long-term practice, the inventors have discovered that the most preferred substrate is a carbon nanotube thin film material. Choosing a carbon nanotube thin film material allows it to work in conjunction with the aforementioned color-changing layer-catalyst layer structure to produce more significant interference colors. These new interference colors exhibit higher significance and better reversibility when achieving hydrogen-sensitive color changing. The principle behind this phenomenon is roughly as follows: a fully absorbing black substrate makes the structural color more prominent; the network structure on the surface of the carbon nanotube thin film gives the material short-range disorder and long-range order, resulting in low angular sensitivity, which is highly beneficial for observing color changes from various angles; and as a flexible and breathable material, carbon nanotubes can adhere firmly to the surface of the leakage source, thereby enabling precise detection of the leakage point.

[0052] In some embodiments, the color-changing layer includes at least one transition metal oxide layer, the material of which includes any one or a combination of two or more of WO3, NiO, TiO2, SnO2, MoO3, VO2, ZnO, In2O3, Fe2O3, Al2O3, V2O5, CuO, and SrTiO3.

[0053] In some embodiments, the color-changing layer includes at least one stacked metal reflective layer and at least one transition metal oxide layer, more preferably, the metal reflective layer and the transition metal oxide layer are stacked alternately. The metal reflective layer and the transition metal oxide layer together form a Fabry-Perot interference structure. The material of the metal reflective layer may include any one or a combination of two or more of Cu, Ag, W, Ti, V, Fe, Cr, Ni, Zn, Al, Mo, Au, Pd, Co, Ta, Pt, and Mg; the material of the transition metal oxide layer may include any one or a combination of two or more of WO3, NiO, TiO2, SnO2, MoO3, VO2, ZnO, In2O3, Fe2O3, Al2O3, V2O5, CuO, and SrTiO3; but is not limited thereto.

[0054] In some embodiments, the material of the metal catalyst layer includes any one or a combination of two or more of Pd, Pt, Ru, Mg, Au, and Ir.

[0055] In some embodiments, the color-changing layer is a transition metal oxide layer with a thickness of 100-5000 nm; in some more preferred embodiments, it is further preferably 100-1000 nm; and even more preferably, in a more preferred embodiment, it is 120-300 nm.

[0056] In some embodiments, the thickness of the metal reflective layer can be above 20 nm, and in some more preferred embodiments, it is preferably 50-300 nm.

[0057] In some embodiments, the thickness of the catalyst layer can be 1-20 nm; in a more preferred embodiment, the thickness of the catalyst layer can be 4-6 nm.

[0058] In some implementations, the reflectance of the hydrogen-sensitive color-changing material at a wavelength of 532 nm can change by up to 70% before and after contact with hydrogen.

[0059] In some embodiments, the color-changing time of the hydrogen-sensitive color-changing material after contact with hydrogen is 30-60 seconds.

[0060] This invention also provides a method for preparing a hydrogen-sensitive color-changing material, comprising the following steps:

[0061] Provide a base.

[0062] The steps involve sequentially forming a color-changing layer and a catalytic layer on a substrate.

[0063] In some embodiments, the color-changing layer and / or catalyst layer can be formed by physical vapor deposition; including but not limited to: any one or a combination of two or more of evaporation deposition, electron beam evaporation, magnetron sputtering, atomic layer deposition, and ion plating, with magnetron sputtering being the preferred method.

[0064] In some embodiments, the preparation method further includes:

[0065] As some typical application examples of the above implementation scheme, the preparation method can be implemented by the following steps:

[0066] Using PVD deposition, a metal reflective layer of a certain thickness is first deposited on the substrate, then transition metal oxide layers of different thicknesses are deposited on the metal reflective layer, and finally a catalyst layer of a certain thickness is deposited.

[0067] PVD deposition methods can include: thermal evaporation deposition, electron beam evaporation, magnetron sputtering, atomic layer deposition, or ion plating.

[0068] The embodiments of the present invention also provide the application of the hydrogen-sensitive color-changing material provided in any of the above embodiments in the field of preparing hydrogen-sensitive color-changing indicators, or in the fields of display, decoration or anti-counterfeiting.

[0069] And its use in the preparation of gas detection materials or gas detection devices.

[0070] In some embodiments, the use may include the preparation of detection materials or devices for one or more of the following gases: hydrogen, methane, ethylene, acetylene, ammonia, hydrogen sulfide, and carbon monoxide. The hydrogen-sensitive color-changing material provided by this invention is primarily used for detecting hydrogen, but it can also detect other flammable gases or irritating / corrosive gases (e.g., ammonia).

[0071] As a specific example of the above application, the method of using the hydrogen-sensitive color-changing material may include the following steps:

[0072] The hydrogen-sensitive color-changing material provided in any of the above embodiments is brought into contact with the gas to be detected, thereby changing the color of the hydrogen-sensitive color-changing material.

[0073] Furthermore, the hydrogen-sensitive color-changing material, after changing color, is brought into full contact with oxygen or oxygen-containing gas, thereby restoring the hydrogen-sensitive color-changing material to its initial color.

[0074] The technical solution of the present invention will be further described in detail below through several embodiments and in conjunction with the accompanying drawings. However, the selected embodiments are only for illustrating the present invention and do not limit the scope of the present invention.

[0075] Example 1

[0076] This embodiment illustrates a hydrogen-sensitive color-changing material, its preparation process, and the testing of its color-changing properties, as detailed below:

[0077] In such Figure 3 On a black, flexible carbon nanotube film substrate, a tungsten film with a thickness of approximately 20 nm is deposited using magnetron sputtering. Then, a tungsten oxide layer is sputtered onto the tungsten film using magnetron sputtering. Preferably, the thickness of the tungsten oxide layer is between 150-400 nm, more preferably 220 nm. At this point, the film changes from black to cyan. A 5 nm thick Pd metal catalytic layer is then deposited to obtain a usable hydrogen-sensitive color-changing material, such as… Figure 4 As shown.

[0078] The color-changing material begins to change color after 30 seconds of pure hydrogen gas being introduced into the surrounding atmosphere at 25°C. After 1 minute, the color change to blue-purple is visible to the naked eye, and after 3 minutes, it turns purple. The color-changing process is as follows: Figure 5 As shown.

[0079] In a 0.6% hydrogen-air mixture, at 80°C, the reflectance changes by 20% over 90 seconds, and the color-changing material changes from cyan to bluish-purple visible to the naked eye. After 180 seconds, the reflectance changes by 30%, turning it purple. Upon introduction of air, the color begins to fade after 1 second and returns to its initial color after 60 seconds.

[0080] In a mixture of 0.9% hydrogen and air, at 80°C, the reflectance changes by 20% over 38 seconds, and the color-changing material changes from cyan to bluish-purple visible to the naked eye. After 177 seconds, the reflectance changes by 30%, turning it purple. Upon introduction of air, the color begins to fade after 1 second and returns to its initial color after 60 seconds.

[0081] In a mixture of 1.2% hydrogen and air, at 80°C, the reflectance changes by 20% over 25 seconds, and the color-changing material changes from cyan to bluish-purple visible to the naked eye. After 62 seconds, the reflectance changes by 30%, turning it purple. Upon being exposed to air, the color begins to fade after 1 second and returns to its initial color after 60 seconds.

[0082] In a mixture of 1.5% hydrogen and air, at 80°C, the reflectance changes by 20% over 20 seconds, and the color-changing material changes from cyan to bluish-purple visible to the naked eye. After 43 seconds, the reflectance changes by 30%, turning it purple. Upon being exposed to air, the color begins to fade after 1 second and returns to its initial color after 60 seconds.

[0083] In a mixture of 2% hydrogen and air, at 80°C, the reflectance changes by 20% over 17 seconds, and the color-changing material appears bluish-purple to the naked eye. After 33 seconds, the reflectance changes by 30%, turning it purple. Upon introduction of air, the color begins to fade after 1 second and returns to its initial color after 60 seconds.

[0084] The relationship between 0.1%-2% hydrogen concentration and reflectivity is as follows: Figure 6 As shown.

[0085] A mixture of 2% hydrogen and air was introduced, and the material changed color afterward. Air was then introduced again, and this process was repeated 30 times to test cyclic stability. The material's response rate and response time remained unchanged. Cyclic stability testing results are as follows: Figure 7 As shown.

[0086] Examples 2-8

[0087] This embodiment, Example 1, describes the hydrogen-sensitive color-changing material, its preparation process, and the testing of its color-changing performance. The differences are as follows:

[0088] By varying the deposition thickness of WO3 to 135, 154, 166, 186, 219, 201, and 213 nm, multiple hydrogen-sensitive color-changing material samples were obtained.

[0089] The series of hydrogen-sensitive color-changing materials prepared in this embodiment have the following colors before color change: Figure 8 As shown, it can be seen that its color has a clear correlation with the thickness of the transition metal oxide layer.

[0090] The color-changing process of its hydrogen-sensitive color-changing material is as follows: Figure 9 As shown, some hydrogen-sensitive color-changing materials change color and are then exposed to air; their reversible color-changing state is as follows. Figure 10As shown, the hydrogen-sensitive color-changing material provided by the present invention has obvious color changes and a certain response speed and reversibility, which meets the application requirements of hydrogen-sensitive color-changing indication.

[0091] Example 9

[0092] This embodiment illustrates a hydrogen-sensitive color-changing material, its preparation process, and the testing of its color-changing performance. It is largely the same as Embodiments 1 and 2, with the following differences:

[0093] The substrate was replaced with a transparent PET substrate, and the rest of the preparation process was the same as in Examples 1 and 2.

[0094] The hydrogen-sensitive color-changing materials it prepares, such as Figure 11 As shown, certain color-changing performance and responsiveness can be achieved.

[0095] Example 10

[0096] This embodiment demonstrates the leakage of a hydrogen-sensitive color-changing material onto a hydrogen cylinder. The preparation method of the hydrogen-sensitive color-changing material is largely the same as in Example 1. The colored color-changing material is attached to the drilled hole in the hydrogen cylinder. Hydrogen gas is introduced from the bottom of the cylinder, and the color-changing process is demonstrated at room temperature. Figure 14a As shown, after 30 seconds of hydrogen gas introduction, the blue film turned purplish-red in some areas, and the discolored area was the drilled hole. After 180 seconds of hydrogen gas introduction, the area near the drilled hole showed a very obvious purplish-red color, which contrasted sharply with the undiscolored blue film. Figure 14b A hydrogen leak demonstration using a different color-changing material was shown. After 30 seconds of hydrogen gas introduction, the magenta film partially turned yellow, at the drilled hole. After 180 seconds of hydrogen gas introduction, the area near the drilled hole showed a very distinct yellow color, contrasting sharply with the unchanged magenta film. Both colors can serve as excellent tools for precise location and warning.

[0097] Example 11

[0098] This embodiment, Example 1, describes the hydrogen-sensitive color-changing material, its preparation process, and the testing of its color-changing performance. The differences are as follows:

[0099] The magnetron sputtered W layer was replaced with Ag, WO3 was replaced with MoO3, and the metal catalyst layer was replaced with Pt.

[0100] The substrate material, the thickness of each layer, and the proportional relationship remain unchanged.

[0101] The hydrogen-sensitive color-changing material obtained has the same color-changing ability as in Example 1, except that the color is different.

[0102] Example 12

[0103] This embodiment, Example 1, describes the hydrogen-sensitive color-changing material, its preparation process, and the testing of its color-changing performance. The differences are as follows:

[0104] The magnetron sputtered metal W layer was replaced with Ti, WO3 was replaced with NiO, and the metal catalyst layer was replaced with Au.

[0105] The substrate material, the thickness of each layer, and the proportional relationship remain unchanged.

[0106] The hydrogen-sensitive color-changing material obtained has the same color-changing ability as in Example 1, except that the color is different.

[0107] Example 13

[0108] This embodiment, Example 1, describes the hydrogen-sensitive color-changing material, its preparation process, and the testing of its color-changing performance. The differences are as follows:

[0109] The thickness of the metal W layer was adjusted to 50nm.

[0110] The base material was replaced with a stainless steel film.

[0111] The prepared hydrogen-sensitive color-changing material has the same color-changing ability as in Example 1.

[0112] Example 14

[0113] This embodiment, Example 1, describes the hydrogen-sensitive color-changing material, its preparation process, and the testing of its color-changing performance. The differences are as follows:

[0114] The thickness of the metal W layer was adjusted to 300nm.

[0115] The base material was replaced with a polyethylene plastic sheet.

[0116] The prepared hydrogen-sensitive color-changing material has the same color-changing ability as in Example 1.

[0117] Example 15

[0118] This embodiment, Example 1, describes the hydrogen-sensitive color-changing material, its preparation process, and the testing of its color-changing performance. The differences are as follows:

[0119] The metal W layer and the metal oxide WO3 layer are stacked cyclically 3 times.

[0120] The prepared hydrogen-sensitive color-changing material has the same color-changing ability as in Example 1.

[0121] Comparative Example 1

[0122] This comparative example provides a hydrogen-sensitive color-changing material and its preparation process, which are largely the same as those in Example 1, with the only difference being:

[0123] The catalyst layer is 30 nm thick.

[0124] The prepared hydrogen-sensitive color-changing material is grayish-green in color. When hydrogen gas is introduced, the color changes to grayish-purple. The color-changing effect is difficult to distinguish with the naked eye. Figure 12 As shown.

[0125] Comparative Example 2

[0126] This comparative example provides a hydrogen-sensitive color-changing material and its preparation process, which are largely the same as those in Example 1, with the only difference being:

[0127] A 220 nm oxide layer was prepared using tungsten oxide powder by spin coating.

[0128] like Figure 13 As shown, the prepared hydrogen-sensitive color-changing material is yellowish-brown and does not exhibit structural color. When hydrogen gas is introduced, it turns bluish-black, but the color is not vibrant enough to serve as a warning.

[0129] Based on the above embodiments and comparative examples, it is clear that the hydrogen-sensitive color-changing material provided in the embodiments of the present invention obtains physical structural color through multi-layered optical interference. Compared with various pigments used in the prior art, it has advantages such as non-fading, environmental friendliness, and the ability to produce an iridescent effect. It changes color significantly upon contact with hydrogen gas and has a short response time, exhibiting excellent hydrogen color-changing indication effect.

[0130] Furthermore, due to its colorful physical structural colors, the hydrogen-sensitive color-changing material provided by this invention has broad application prospects in display, decoration, anti-counterfeiting and other fields.

[0131] Furthermore, the hydrogen-sensitive color-changing material provided in this embodiment of the invention can be prepared by a relatively convenient deposition method, which is time-saving, has a simplified process, and does not generate a large amount of chemical pollutants. This is very beneficial for industrial application and meets the increasing demand for hydrogen detection.

[0132] Specifically, the colors of the multi-color patterns obtained by the optical interference of the metal medium in the embodiments of the present invention are physical structural colors. Compared with various pigments used in the prior art, they have advantages such as non-fading, environmental friendliness, and iridescent effect, and have broad application prospects in display, decoration, anti-counterfeiting and other fields.

[0133] It should be understood that the above embodiments are merely illustrative of the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A gas detection method, characterized in that, include: By attaching a hydrogen-sensitive color-changing material to the surface of the leak source and observing the local color change of the hydrogen-sensitive color-changing material, the leak point can be accurately detected. The hydrogen-sensitive color-changing material comprises at least one base layer, at least one color-changing layer, and at least one catalyst layer stacked together. When the hydrogen-sensitive color-changing material comes into contact with hydrogen gas, the catalyst layer can convert at least a portion of the hydrogen gas into active hydrogen atoms. The structure of the color-changing layer specifically includes at least one layer of metal reflective layer and at least one layer of transition metal oxide layer stacked together. The metal reflective layer and the transition metal oxide layer cooperate to form a Fabry-Perot interference structure. Physical structural color is obtained through optical interference of multiple layers. Moreover, the color-changing layer can be reduced by active hydrogen atoms to change its color, thereby changing the color of the hydrogen-sensitive color-changing material. The substrate layer is selected from carbon nanotube thin films. The metal reflective layer is made of any one or more of Cu, Ag, W, Ti, V, Fe, Cr, Ni, Zn, Al, Mo, Au, Pd, Co, Ta, Pt, and Mg. The thickness of the metal reflective layer is 50-300 nm. The transition metal oxide layer is made of any one or more of WO3, NiO, TiO2, SnO2, MoO3, VO2, ZnO, In2O3, Fe2O3, Al2O3, V2O5, CuO, and SrTiO3. The catalyst layer is made of any one or more of Pd, Pt, Ru, Mg, Au, and Ir.

2. The gas detection method according to claim 1, characterized in that, The stacking configuration includes a multi-cycle alternating stacking configuration.

3. The gas detection method according to claim 1, characterized in that, The method for preparing the color-changing layer includes any one or a combination of two or more of the following: evaporation deposition, electron beam evaporation, magnetron sputtering, atomic layer deposition, and ion plating.

4. The gas detection method according to claim 1, characterized in that, The thickness of the transition metal oxide layer is 100-5000 nm.

5. The gas detection method according to claim 1, characterized in that, The thickness of the catalyst layer is 1-20 nm.

6. The gas detection method according to claim 1, characterized in that, Also includes: The hydrogen-sensitive color-changing material is brought into full contact with oxygen or oxygen-containing gas after it has changed color, thereby restoring the hydrogen-sensitive color-changing material to its initial color.

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