Hydrogen-sensitive temperature-changing material and its preparation method, coating and application, system

Abstract

The present invention discloses a hydrogen-sensitive temperature-variable material and its preparation method, coating, application and system, and relates to the technical field of hydrogen-sensitive materials. The hydrogen-sensitive temperature-variable material comprises: solid organic particles, and a composite catalyst, wherein the composite catalyst is combined with the solid organic particles by physical adsorption; wherein the composite catalyst comprises a carrier with a porous structure and metal nanoparticles loaded on the carrier, and the solid organic particles can react with hydrogen to release heat under the catalytic action of the metal nanoparticles. The present invention provides a new hydrogen-sensitive temperature-variable material to indicate hydrogen leakage by temperature change.

Description

Technical Field

[0001] The present invention relates to the technical field of hydrogen-sensitive materials, and in particular to a hydrogen-sensitive temperature-variable material and a preparation method, a coating, an application and a system thereof. Background Art

[0002] As a new type of energy, hydrogen energy is an important means to deal with the reduction of fossil energy reserves and global warming. At the same time, hydrogen is colorless, odorless, easy to spread, flammable and explosive. Leakage will bring serious dangers. Therefore, real-time monitoring of hydrogen leakage and prevention of hydrogen leakage are issues that need to be addressed in the use of hydrogen energy.

[0003] At present, hydrogen sensors are the main means of hydrogen leakage monitoring. There are many types of them, all of which have their own advantages, but there are still certain limitations. Electrochemical sensors have a limited lifespan and need to be calibrated regularly. They are suitable for short-term hydrogen leakage monitoring; catalytic sensors do not have hydrogen selectivity, are easily affected by other gases, and require an oxygen environment to achieve detection; work function sensors have drift and aging effects, are affected by environmental parameters, and the stability of the environment needs to be ensured during use; mechanical sensors have slow response times, are easily induced by hydrogen aging, cannot feedback leakage information in a timely manner, and have a high potential risk; optical sensors are affected by ambient light and are easily affected by pollution and aging effects; acoustic sensors require a certain understanding of the acoustic properties of sound propagation materials and more electronic equipment to improve accuracy, are costly, and cannot be widely used.

[0004] Existing hydrogen detection sensors have many problems in terms of application scope and application conditions, and cannot meet the safety issues in the process of hydrogen energy utilization. With the research and application of hydrogen energy, the realization of a timely, accurate and effective hydrogen leakage monitoring system is an urgent problem that still needs to be solved in the safe use of hydrogen resources. Summary of the invention

[0005] The main purpose of the present invention is to propose a hydrogen-sensitive temperature-variable material and its preparation method, coating, application and system, aiming to provide a new hydrogen-sensitive temperature-variable material to indicate hydrogen leakage through temperature changes.

[0006] To achieve the above-mentioned purpose, the present invention proposes a hydrogen-sensitive temperature-variable material, comprising: solid organic particles, and a composite catalyst, wherein the composite catalyst is combined with the solid organic particles by physical adsorption; wherein the solid organic particles include at least one of 1,4-bis(phenylethynyl)benzene, diphenylacetylene, and 1,4-diphenylbutadiyne; the composite catalyst includes a carrier with a porous structure and metal nanoparticles loaded on the carrier, and the solid organic particles can react with hydrogen to release heat under the catalytic action of the metal nanoparticles.

[0007] In one embodiment, the carrier comprises at least one of activated carbon, graphene oxide, porous graphene aerogel, FAU layered zeolite, melamine foam, and / or;

[0008] The material of the metal nanoparticles includes at least one of palladium, platinum, iridium, ruthenium, rhodium, osmium and silver.

[0009] In one embodiment, the mass ratio of the composite catalyst to the solid organic particles is 1:(1-3), and / or;

[0010] The mass proportion of the metal nanoparticles in the composite catalyst is 5% to 10%.

[0011] The present invention also provides a method for preparing a hydrogen-sensitive temperature-variable material, comprising the following steps:

[0012] The metal nanoparticles are loaded on a carrier having a porous structure to obtain a composite catalyst;

[0013] The solid organic particles are combined with the composite catalyst by physical adsorption to obtain a hydrogen-sensitive temperature-variable material; wherein the solid organic particles can react with hydrogen to release heat under the catalytic action of the metal nanoparticles.

[0014] In one embodiment, the step of loading the metal nanoparticles on a carrier having a porous structure to obtain a composite catalyst comprises:

[0015] Dropping the metal salt solution into the suspension in which the carrier is dispersed;

[0016] The reducing agent is dropped into the suspension, and the suspension is centrifuged and freeze-dried to obtain a composite catalyst.

[0017] In one embodiment, the step of combining solid organic particles with the composite catalyst by physical adsorption to obtain a hydrogen-sensitive temperature-variable material comprises:

[0018] Solid organic particles are added into an organic solvent and dispersed to obtain a mixed liquid.

[0019] Adding the composite catalyst into the mixed solution and performing ultrasonic dispersion to obtain a composite;

[0020] After evaporating the organic solvent in the composite, drying and grinding are performed in sequence to obtain the hydrogen-sensitive temperature-variable material.

[0021] In one embodiment, the grinding is performed using a ball mill for a grinding time of 12-20 hours.

[0022] The present invention also provides a hydrogen-sensitive temperature-variable coating, comprising a hydrogen-sensitive temperature-variable material or a hydrogen-sensitive temperature-variable material prepared by the preparation method described above.

[0023] The present invention also provides an application of a hydrogen-sensitive temperature-variable coating, comprising:

[0024] The hydrogen-sensitive temperature-variable coating is applied to the surface of the object to be detected.

[0025] Monitor whether the surface temperature of the hydrogen-sensitive variable temperature coating changes,

[0026] When the surface temperature of the hydrogen-sensitive variable temperature coating changes, confirm that hydrogen exists in the environment of the object to be tested.

[0027] The present invention also proposes a hydrogen leakage monitoring system, which includes a hydrogen-sensitive variable temperature coating arranged on the surface of an object to be tested, a temperature acquisition unit for collecting temperature information of the hydrogen-sensitive variable temperature coating, a timing unit for collecting the temperature change time of the hydrogen-sensitive variable temperature coating, and a control unit, a data transmission unit, a data storage processing unit and an alarm unit electrically connected to the temperature acquisition unit and the timing unit.

[0028] The technical solution of the present invention adopts a composite catalyst including a carrier with a porous structure and metal nanoparticles loaded on the carrier. The composite catalyst can adsorb hydrogen and break the chemical bonds in the hydrogen molecules to form active hydrogen atoms, thereby catalyzing the hydrogenation reaction between hydrogen and solid organic particles. For solid organic particles, the reaction rate of the solid organic particles themselves with hydrogen is extremely slow and it is difficult to directly apply it to temperature-variable coatings. Therefore, in the present invention, the carrier with a porous structure provides adsorption sites and active sites to promote the transmission and diffusion of hydrogen, so that the metal nanoparticles loaded on the carrier are fully in contact with the solid organic particles. The metal nanoparticles convert hydrogen molecules into active hydrogen atoms and react with the solid organic particles to release heat.

[0029] The hydrogen-sensitive variable temperature material and hydrogen-sensitive variable temperature coating provided by the present invention are safe and easy to apply. The detection of the temperature change caused by the release of heat indicates the presence of hydrogen, which makes up for the short life of the electrochemical sensor, solves the problem of realizing hydrogen detection in an oxygen-free environment, is not easily affected by the environment to cause corrosion or aging, etc., has low cost and is suitable for wide application. The present invention is an irreversible exothermic type. The coating is coated on a certain carrier and posted to a fixed position such as a pipeline interface or a weld. After the leak point is repaired, only a new one needs to be posted. When applied to disposable application scenarios such as packaging boxes and hydrogen storage bottles, it can be directly coated. The present invention has a wide range of application scenarios and can be applied under a variety of working conditions. The coating has good stability and can realize the state to be tested for possible leak points for a long time. It can be used under oxygen-free conditions, is not easily interfered by other gases, has extremely strong selectivity, and can timely feedback leakage information when a leak occurs. The present invention can realize the capture and recording function for subtle leaks. For intermittent and accidental leaks that are not easily identified by existing means, the temperature change effect of the coating can be recorded, which plays a warning role before the leak expands. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0031] Figure 1 This is a SEM image of the hydrogen-sensitive temperature-variable material prepared in Example 1 of the present invention;

[0032] Figure 2 Another SEM image of the hydrogen-sensitive temperature-variable material prepared in Example 1 of the present invention;

[0033] Figure 3 A TEM transmission image of the hydrogen-sensitive temperature-variable material prepared in Example 1 of the present invention;

[0034] Figure 4 Another TEM transmission image of the hydrogen-sensitive temperature-variable material prepared in Example 1 of the present invention;

[0035] Figure 5 Another TEM transmission image of the hydrogen-sensitive temperature-variable material prepared in Example 1 of the present invention;

[0036] Figure 6 The XRD characterization diagram of the hydrogen-sensitive temperature-variable material prepared in Example 1 before and after the reaction with hydrogen;

[0037] Figure 7 This is an XPS graph of the hydrogen-sensitive temperature-variable material prepared in Example 1;

[0038] Figure 8 This is another XPS graph of the hydrogen-sensitive temperature-variable material prepared in Example 1;

[0039] Fig. 9 This is another XPS graph of the hydrogen-sensitive temperature-variable material prepared in Example 1;

[0040] Fig.10 The temperature rise diagram is a graph showing the heat released by reacting 30 mg of the hydrogen-sensitive temperature-variable material prepared in Examples 1, 2, and 3 with hydrogen in a pure hydrogen (100%) environment;

[0041] Fig.11 The temperature rise diagram is when 30 mg of the hydrogen-sensitive temperature-variable material prepared in Examples 1, 2, and 3 respectively reacts with hydrogen in a hydrogen (50%) environment to release heat.

[0042] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0043] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0044] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, movement status, etc. between the components in a certain specific posture. If the specific posture changes, the directional indication will also change accordingly.

[0045] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features limited to "first" and "second" may explicitly or implicitly include at least one of the features. In addition, if "and / or" or "and / or" appears in the full text, its meaning includes three parallel solutions. Taking "A and / or B" as an example, it includes solution A, solution B, or solutions that satisfy both A and B. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0046] To achieve the above-mentioned purpose, the present invention proposes a hydrogen-sensitive temperature-variable material, comprising: solid organic particles, and a composite catalyst, wherein the composite catalyst is combined with the solid organic particles by physical adsorption; wherein the solid organic particles include at least one of 1,4-bis(phenylethynyl)benzene, diphenylacetylene, and 1,4-diphenylbutadiyne; the composite catalyst includes a carrier with a porous structure and metal nanoparticles loaded on the carrier, and the solid organic particles can react with hydrogen to release heat under the catalytic action of the metal nanoparticles.

[0047] The technical solution of the present invention adopts a composite catalyst including a carrier with a porous structure and metal nanoparticles loaded on the carrier. The composite catalyst can adsorb hydrogen and break the chemical bonds in the hydrogen molecules to form active hydrogen atoms, thereby catalyzing the hydrogenation reaction between hydrogen and solid organic particles. For solid organic particles, the reaction rate of the solid organic particles themselves with hydrogen is extremely slow and it is difficult to directly apply it to temperature-variable coatings. Therefore, in the present invention, the carrier with a porous structure provides adsorption sites and active sites to promote the transmission and diffusion of hydrogen, so that the metal nanoparticles loaded on the carrier are fully in contact with the solid organic particles. The metal nanoparticles convert hydrogen molecules into active hydrogen atoms and react with the solid organic particles to release heat.

[0048] In an embodiment of the present invention, the solid organic particles include at least one of 1,4-bis(phenylethynyl)benzene, diphenylacetylene, 1,4-diphenylbutadiyne or other solid organic particles capable of solid phase hydrogenation at room temperature and pressure, the carrier includes at least one of activated carbon, graphene oxide, porous graphene aerogel, FAU layered zeolite, and melamine foam, and the material of the metal nanoparticles includes at least one of palladium, platinum, iridium, ruthenium, rhodium, osmium, and silver. The embodiment of the present invention uses porous structures such as activated carbon, graphene oxide, porous graphene aerogel, FAU layered zeolite, and melamine foam as carriers, which provide good adsorption sites and active sites, and are conducive to achieving full utilization of solid organic particles.

[0049] In an embodiment of the present invention, the mass ratio of the composite catalyst to the solid organic particles is 1:(1-3), and the mass proportion of the metal nanoparticles in the composite catalyst is 5%-10%.

[0050] The present invention also provides a method for preparing a hydrogen-sensitive temperature-variable material, comprising the following steps:

[0051] The metal nanoparticles are loaded on a carrier having a porous structure to obtain a composite catalyst;

[0052] The solid organic particles are combined with the composite catalyst by physical adsorption to obtain a hydrogen-sensitive temperature-variable material; wherein the solid organic particles can react with hydrogen to release heat under the catalytic action of the metal nanoparticles.

[0053] In an embodiment of the present invention, the step of loading the metal nanoparticles on a carrier having a porous structure to obtain a composite catalyst comprises:

[0054] Dropping the metal salt solution into the suspension in which the carrier is dispersed;

[0055] The reducing agent is dropped into the suspension, and the suspension is centrifuged and freeze-dried to obtain a composite catalyst.

[0056] The metal salt solution may be a solution obtained by dissolving a palladium salt, a platinum salt, an iridium salt, a ruthenium salt, a rhodium salt, an osmium salt, a silver salt, etc. in deionized water. For example, the metal salt solution may be a sodium tetrachloropalladate solution. The reducing agent may be a NaBH4 solution for example.

[0057] In an embodiment of the present invention, the step of combining the solid organic particles with the composite catalyst by physical adsorption to obtain the hydrogen-sensitive temperature-variable material comprises:

[0058] Solid organic particles are added into an organic solvent and dispersed to obtain a mixed liquid.

[0059] Adding the composite catalyst to the mixed solution, and performing ultrasonic dispersion for 30 to 60 minutes to obtain a composite;

[0060] After evaporating the organic solvent in the composite, drying and grinding are performed in sequence to obtain the hydrogen-sensitive temperature-variable material.

[0061] In an embodiment of the present invention, the grinding is performed using a ball mill for a grinding time of 12-20 hours.

[0062] It should be noted that the purpose of grinding is that after the solvent is evaporated and dried, the compound will partially aggregate and disperse, so further grinding is required to avoid agglomeration into blocks. (For the case where the skeleton structure or carrier cannot be formed, the product is in powder form after evaporation and drying. After grinding, it is more conducive to application in coatings, giving full play to the advantages of hydrogen-sensitive temperature-variable materials.)

[0063] The present invention also provides a hydrogen-sensitive temperature-variable coating, comprising a hydrogen-sensitive temperature-variable material or a hydrogen-sensitive temperature-variable material prepared by the preparation method described above.

[0064] The present invention also provides an application of a hydrogen-sensitive temperature-variable coating, comprising:

[0065] The hydrogen-sensitive temperature-variable coating is applied to the surface of the object to be detected.

[0066] Monitor whether the surface temperature of the hydrogen-sensitive variable temperature coating changes,

[0067] When the surface temperature of the hydrogen-sensitive variable temperature coating changes, confirm that hydrogen exists in the environment of the object to be tested.

[0068] The hydrogen-sensitive variable temperature material and hydrogen-sensitive variable temperature coating provided by the present invention are safe and easy to apply. The detection of the temperature change caused by the release of heat indicates the presence of hydrogen, which makes up for the short life of the electrochemical sensor, solves the problem of realizing hydrogen detection in an oxygen-free environment, is not easily affected by the environment to cause corrosion or aging, etc., has low cost and is suitable for wide application. The present invention is an irreversible exothermic type. The coating is coated on a certain carrier and posted to a fixed position such as a pipeline interface or a weld. After the leak point is repaired, only a new one needs to be posted. When applied to disposable application scenarios such as packaging boxes and hydrogen storage bottles, it can be directly coated. The present invention has a wide range of application scenarios and can be applied under a variety of working conditions. The coating has good stability and can realize the state to be tested for possible leak points for a long time. It can be used under oxygen-free conditions, is not easily interfered by other gases, has extremely strong selectivity, and can timely feedback leakage information when a leak occurs. The present invention can realize the capture and recording function for subtle leaks. For intermittent and accidental leaks that are not easily identified by existing means, the temperature change effect of the coating can be recorded, which plays a warning role before the leak expands.

[0069] The present invention also proposes a hydrogen leakage monitoring system, which includes a hydrogen-sensitive variable temperature coating arranged on the surface of an object to be tested, a temperature acquisition unit for collecting temperature information of the hydrogen-sensitive variable temperature coating, a timing unit for collecting the temperature change time of the hydrogen-sensitive variable temperature coating, and a control unit, a data transmission unit, a data storage processing unit and an alarm unit electrically connected to the temperature acquisition unit and the timing unit.

[0070] The hydrogen leakage monitoring system provided by the embodiment of the present invention can obtain the hydrogen concentration in the environment where the coating is located through the heat release rate and / or temperature change amplitude of the coating. For example, a large amount of heat release / fast temperature rise rate indicates a high hydrogen concentration in the environment where the coating is located. When using temperature-variable hydrogen concentration indication, the timing unit can be used to obtain the response time of the hydrogen leakage detection coating from the beginning of contact with hydrogen to the occurrence of temperature rise changes, and the timing unit can also be used to obtain the time from the beginning of contact with hydrogen to the temperature reaching the maximum value and no longer rising.

[0071] The hydrogen leakage monitoring coating provided in the embodiment of the present invention is identified and alarmed by an infrared camera and an alarm system. When a hydrogen leak occurs, the hydrogen leakage monitoring coating will heat up. After the infrared sensing camera captures the change, it will be transmitted to the computer terminal for identification and alarm.

[0072] The technical solution of the present invention is further described in detail below in conjunction with specific embodiments and drawings. It should be understood that the following embodiments are only used to explain the present invention and are not used to limit the present invention.

[0073] Example 1

[0074] This embodiment provides a method for preparing a hydrogen-sensitive temperature-variable material and a hydrogen-sensitive temperature-variable material prepared by the preparation method. The preparation method comprises:

[0075] (1) 100 mg of graphene was added to 50 mL of deionized water and stirred under ultrasound for 2 h to form a uniformly dispersed suspension;

[0076] (2) 1.0 mmol / g sodium tetrachloropalladate was added dropwise into 50 mL of graphene oxide suspension and ultrasonically dispersed for 30 min;

[0077] (3) Add excess NaBH4 solution dropwise to the solution in step (2) with continuous stirring, and then filter, wash, centrifuge and freeze-dry to obtain graphene oxide-supported Pd nanoparticles, i.e., rGO / Pd catalyst.

[0078] (4) Add DEB powder into dichloromethane and disperse it by ultrasonication to form a suspension; wherein DEB refers to 1,4-bis(phenylethynyl)benzene.

[0079] (5) The rGO / Pd catalyst was added to the DEB suspension and ultrasonically dispersed for 30 min to form an rGO / Pd-DEB composite material mixture solution; wherein the mass ratio of the rGO / Pd catalyst to the DEB powder was 1:3.

[0080] (6) The hydrogen-sensitive temperature-variable material was obtained by evaporating the dichloromethane solution, vacuum drying at 60 °C for 24 h, and ball milling for 12 h.

[0081] Example 2

[0082] The difference between this embodiment and embodiment 1 is that the mass ratio of rGO / Pd catalyst to DEB powder is 1:1.

[0083] Specifically, the preparation method of this embodiment includes:

[0084] (1) 100 mg of graphene was added to 50 mL of deionized water and stirred under ultrasound for 2 h to form a uniformly dispersed suspension;

[0085] (2) 1.0 mmol / g sodium tetrachloropalladate was added dropwise into 50 mL of graphene oxide suspension and ultrasonically dispersed for 30 min;

[0086] (3) Add excess NaBH4 solution dropwise to the solution in step (2) with continuous stirring, and then filter, wash, centrifuge and freeze-dry to obtain graphene oxide-supported Pd nanoparticles, i.e., rGO / Pd catalyst.

[0087] (4) Add DEB powder into dichloromethane and disperse it by ultrasonication to form a suspension; wherein DEB refers to 1,4-bis(phenylethynyl)benzene.

[0088] (5) The rGO / Pd catalyst was added to the DEB suspension and ultrasonically dispersed for 30 min to form an rGO / Pd-DEB composite material mixture solution; wherein the mass ratio of the rGO / Pd catalyst to the DEB powder was 1:1.

[0089] (6) The hydrogen-sensitive temperature-variable material was obtained by evaporating the dichloromethane solution, vacuum drying at 60 °C for 24 h, and ball milling for 12 h.

[0090] Example 3

[0091] The difference between this embodiment and embodiment 1 is that the mass ratio of rGO / Pd catalyst to DEB powder is 1:2.

[0092] Specifically, the preparation method of this embodiment includes:

[0093] (1) 100 mg of graphene was added to 50 mL of deionized water and stirred under ultrasound for 2 h to form a uniformly dispersed suspension;

[0094] (2) 1.0 mmol / g sodium tetrachloropalladate was added dropwise into 50 mL of graphene oxide suspension and ultrasonically dispersed for 30 min;

[0095] (3) Add excess NaBH4 solution dropwise to the solution in step (2) with continuous stirring, and then filter, wash, centrifuge and freeze-dry to obtain graphene oxide-supported Pd nanoparticles, i.e., rGO / Pd catalyst.

[0096] (4) Add DEB powder into dichloromethane and disperse it by ultrasonication to form a suspension; wherein DEB refers to 1,4-bis(phenylethynyl)benzene.

[0097] (5) The rGO / Pd catalyst was added to the DEB suspension and ultrasonically dispersed for 30 min to form an rGO / Pd-DEB composite material mixture solution; wherein the mass ratio of the rGO / Pd catalyst to the DEB powder was 1:2.

[0098] (6) The hydrogen-sensitive temperature-variable material was obtained by evaporating the dichloromethane solution, vacuum drying at 60 °C for 24 h, and ball milling for 12 h.

[0099] Example 4

[0100] This embodiment provides a method for preparing a hydrogen-sensitive temperature-variable material and a hydrogen-sensitive temperature-variable material prepared by the preparation method. The preparation method comprises:

[0101] Using melamine as a carrier, the melamine foam needs to be treated before loading the nanoparticles, including the following steps:

[0102] (1) Wash the melamine sponge precursor with deionized water and ethanol and dry it at 80 °C for 12 h;

[0103] (2) Calcination of washed melamine sponge MFC at 800 °C (heating / cooling rate 5 °C / min) for 2 h in an Ar atmosphere (the purpose of this step is to obtain C-N bonds after calcination. The presence of C-N bonds is conducive to the distribution of metal nanoparticles on the carrier);

[0104] (3) Wash the MFC with deionized water and ethanol and dry it at 80 °C for 12 h.

[0105] The steps of loading metal nanoparticles and adsorbing reactants on MFC are as follows:

[0106] (4) Soak the MFC in 10 ml of 0.5 mg / ml sodium rhodium chloride (RhCl3) solution under vacuum for 24 h;

[0107] (5) Add sodium borohydride solution dropwise under ultrasonic treatment to reduce MFC, and the resulting solution is allowed to stand for 24 hours and then washed with deionized water;

[0108] (6) The Rh / MFC catalyst was dried at 20°C in vacuum for 24 h, and the dried Rh / MFC was immersed in an organic solution containing 100 mg DEB in vacuum for 24 h;

[0109] (7) Rh / MFC / DEB complex with evaporation of solvent.

[0110] Example 5

[0111] This embodiment provides a method for preparing a hydrogen-sensitive temperature-variable material and a hydrogen-sensitive temperature-variable material prepared by the preparation method. The preparation method comprises:

[0112] (1) 100 mg of graphene was added to 50 mL of deionized water and stirred under ultrasound for 2 h to form a uniformly dispersed suspension;

[0113] (2) 1.0 mmol / g sodium tetrachloropalladate was added dropwise into 50 mL of graphene oxide suspension and ultrasonically dispersed for 30 min;

[0114] (3) Add excess NaBH4 solution dropwise to the solution in step (2) with continuous stirring, and then filter, wash, centrifuge and freeze-dry to obtain graphene oxide-supported Pd nanoparticles, i.e., rGO / Pd catalyst.

[0115] (4) adding diphenylacetylene powder into dichloromethane and ultrasonically dispersing the mixture to form a suspension;

[0116] (5) The rGO / Pd catalyst was added into the DEB suspension and ultrasonically dispersed for 30 min to form an rGO / Pd-toluene composite material mixture solution; wherein the mass ratio of the rGO / Pd catalyst to the toluene powder was 1:1.

[0117] (6) The hydrogen-sensitive temperature-variable material was obtained by evaporating the dichloromethane solution, vacuum drying at 60 °C for 24 h, and ball milling for 12 h.

[0118] Example 6

[0119] 10 mg of the hydrogen-sensitive temperature-variable material prepared in Example 1 was mixed with 400 mg of acrylic resin (resin), 100 mg of varnish (oil), 400 mg of acetone (solvent), and 90 mg of PDMS (additive) to obtain a hydrogen-sensitive temperature-variable coating.

[0120] Apply the hydrogen-sensitive temperature-variable coating to the surface of the object to be tested.

[0121] Example 7

[0122] The present embodiment provides a hydrogen leakage monitoring system, comprising a hydrogen-sensitive color-changing coating prepared by Example 5, which is arranged on the surface of an object to be tested, a temperature acquisition unit for collecting temperature information of the hydrogen-sensitive temperature-changing coating, a timing unit for collecting the temperature change time of the hydrogen-sensitive temperature-changing coating, and a control unit, a data transmission unit, a data storage processing unit and an alarm unit electrically connected to the temperature acquisition unit and the timing unit.

[0123] Performance Testing

[0124] (1) Figure 1 and Figure 2 They are SEM images of the hydrogen-sensitive temperature-variable material prepared in Example 1. It can be seen that the prepared composite has no agglomeration phenomenon and the composite layer is flat, which proves that the composite effect is very good. A good composite effect is conducive to the occurrence of the reaction after encountering hydrogen.

[0125] (2) Figure 3 , Figure 4 and Figure 5 They are TEM transmission images of the hydrogen-sensitive temperature-variable material prepared in Example 1. The black dots in the figure are Pd. Figure 3It can be seen that the distribution of Pd element is good and there is no agglomeration phenomenon; it also shows that the Pd element is successfully doped and it is Pd that plays a catalytic role in the reaction. Figure 4 It can be seen that the distribution of Pd elements is good, dense and not agglomerated. Under this distribution, Pd has excellent catalytic ability for hydrogen. Figure 5 The TEM images were analyzed and the lattice spacing of the elements was measured, which was found to be 0.2304 nm, corresponding to the (111) crystal plane of the Pd element, further confirming the successful doping of the Pd element.

[0126] (3) reacting the hydrogen-sensitive temperature-variable material prepared in Example 1 with hydrogen, Figure 6 The XRD characterization images of the hydrogen-sensitive variable temperature material prepared in Example 1 before and after the reaction with hydrogen. Hydrogenated DEB means that the hydrogen-sensitive variable temperature material has reacted with hydrogen, and virgin DEB means that the hydrogen-sensitive variable temperature material has not reacted with hydrogen. Figure 6 It can be seen that the Pd / C catalyst first dissociates molecular hydrogen into atomic hydrogen, and then the atomic hydrogen directly reacts with the unsaturated bonds of the DEB molecules within its migration distance. The DEB molecules react with different amounts of atomic hydrogen to form different DEB species. These DEB species include 2H-DEB (formed by the reaction of one DEB molecule with two hydrogen atoms), 4H-DEB (formed by the reaction of one DEB molecule with four hydrogen atoms), 6H-DEB (formed by the reaction of one DEB molecule with six hydrogen atoms), 8H-DEB (formed by the reaction of one DEB molecule with eight atomic hydrogen), etc. It can be seen that a strong characteristic peak appears at 15 degrees after the reaction, which is consistent with the XRD spectra of 2H-DEB, 4H-DEB, 6H-DEB, and 8H-DEB near 15 degrees. Therefore, it is proved that DEB and H2 undergo a catalytic hydrogenation reaction to generate hydrogenation products of 2H-DEB, 4H-DEB, 6H-DEB, and 8H-DEB.

[0127] (4) Figures 7 to 9 This is the XPS graph of the hydrogen-sensitive temperature-variable material prepared in Example 1, wherein: Figure 7 This is the XPS spectrum of the hydrogen-sensitive temperature-variable material DEB-Pd / C (3:1, dichloromethane mixture) prepared in Example 1, from which the peaks of Pd and C can be clearly seen; Figure 8 C—C bond and C—O bond can be seen in the graph, indicating the presence of C support in the Pd / C catalyst. Fig. 9 It can be seen that the Pd catalyst is composed of Pd 0 and Pd 2+ Here, Pd in ​​the Pd / C catalyst 2+The presence of may be due to the surface oxidation of palladium nanoparticles to form PdO. However, when the composite material comes into contact with hydrogen and reacts to release heat, a reaction may occur: Pd 2+ +H2=Pd+2H + This reaction can convert Pd 2+ It is converted into Pd nanoparticles, and Pd nanoparticles can dissociate H2 molecules into active H atoms. The active H atoms come into contact with unsaturated organic matter to undergo catalytic hydrogenation reaction and release heat.

[0128] (5) 30 mg of the hydrogen-sensitive temperature-variable material prepared in Examples 1, 2, and 3 were respectively reacted with hydrogen in a pure hydrogen (100%) environment to release heat and the temperature rise diagram was obtained.

[0129] See also Fig.10 , Fig.10 The figure shows the heat rise diagram of the hydrogen-sensitive temperature-variable material (30 mg) with a mass ratio of rGO / Pd catalyst to DEB powder of 1:1, 2:1, and 3:1 respectively, in a pure hydrogen (hydrogen flow rate 500 ml / min) environment. Fig.10 It can be seen that the heating rate and the highest temperature of the material with a ratio of 1:1 are higher than those of 2:1 and 3:1; similarly, the effect of the material with a ratio of 2:1 is better than that of 3:1. In the figure, the hydrogen-sensitive variable temperature material with a ratio of 1:1 rises from an initial 30.8℃ to 102.6℃ within 6s; the hydrogen-sensitive material with a ratio of 2:1 rises from an initial 29.9℃ to 97℃ within 9s; the hydrogen-sensitive material with a ratio of 3:1 rises from an initial 23.4℃ to 92℃ within 8s.

[0130] (6) 30 mg of the hydrogen-sensitive temperature-variable material prepared in Examples 1, 2, and 3 were respectively reacted with hydrogen in a hydrogen (50%) environment to release heat and the temperature rise diagram was obtained.

[0131] See also Fig.11 , Fig.11 The figure shows the heat rise diagram of hydrogen-sensitive variable temperature materials (30 mg) with mass ratios of rGO / Pd catalyst and DEB powder of 1:1, 2:1, and 3:1 respectively, reacting with hydrogen in a 50% hydrogen (hydrogen flow rate 500 ml / min) environment. It can be seen from the figure that the heating rate and the highest temperature of the material with a ratio of 1:1 are higher than those of 2:1 and 3:1; similarly, the effect of the material with a ratio of 2:1 is better than that of 3:1. In the figure, the hydrogen-sensitive variable temperature material with a ratio of 1:1 rises from the initial 31.6°C to 44.1°C within 9s; the hydrogen-sensitive material with a ratio of 2:1 rises from the initial 31.5°C to 42°C within 8s; the hydrogen-sensitive material with a ratio of 3:1 rises from the initial 31.2°C to 41.4°C within 8s.

[0132] The above description is only an exemplary embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the technical concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A hydrogen leak monitoring system, characterized in that: The invention comprises a hydrogen-sensitive temperature-variable coating arranged on the surface of the object to be tested, a temperature acquisition unit for acquiring temperature information of the hydrogen-sensitive temperature-variable coating, a timing unit for acquiring temperature-changing time of the hydrogen-sensitive temperature-variable coating, and a control unit, a data transmission unit, a data storage processing unit and an alarm unit electrically connected to the temperature acquisition unit and the timing unit; wherein the hydrogen-sensitive temperature-variable coating comprises a hydrogen-sensitive temperature-variable material, and the hydrogen-sensitive temperature-variable material comprises: Solid organic particles, and A composite catalyst, wherein the composite catalyst is combined with the solid organic particles by physical adsorption; The composite catalyst comprises a carrier with a porous structure and metal nanoparticles loaded on the carrier. The solid organic particles can react with hydrogen to release heat under the catalytic effect of the metal nanoparticles; The solid organic particles include at least one of 1,4-bis(phenylethynyl)benzene, diphenylacetylene and 1,4-diphenylbutadiyne. The carrier includes at least one of activated carbon, graphene oxide, porous graphene aerogel, FAU layered zeolite, and melamine foam. The material of the metal nanoparticles includes at least one of palladium, platinum, iridium, ruthenium, rhodium, osmium, and silver; the mass ratio of the composite catalyst to the solid organic particles is 1:(1-3).

2. The hydrogen leakage monitoring system according to claim 1, characterized in that: The mass proportion of the metal nanoparticles in the composite catalyst is 5% to 10%.

3. The hydrogen leakage monitoring system according to claim 1, characterized in that: The hydrogen-sensitive temperature-variable material is prepared by the following steps: The metal nanoparticles are loaded on a carrier having a porous structure to obtain a composite catalyst; The solid organic particles are combined with the composite catalyst by physical adsorption to obtain a hydrogen-sensitive temperature-variable material; wherein the solid organic particles can react with hydrogen to release heat under the catalytic action of the metal nanoparticles.

4. The hydrogen leakage monitoring system according to claim 3, characterized in that: The step of loading the metal nanoparticles on a carrier having a porous structure to obtain a composite catalyst comprises: Dropping the metal salt solution into the suspension in which the carrier is dispersed; The reducing agent is dropped into the suspension, and the suspension is centrifuged and freeze-dried to obtain a composite catalyst.

5. The hydrogen leakage monitoring system according to claim 3, characterized in that: The step of combining the solid organic particles with the composite catalyst by physical adsorption to obtain the hydrogen-sensitive temperature-variable material comprises: Solid organic particles are added into an organic solvent and dispersed to obtain a mixed liquid. Adding the composite catalyst into the mixed solution and performing ultrasonic dispersion to obtain a composite; After evaporating the organic solvent in the composite, drying and grinding are performed in sequence to obtain the hydrogen-sensitive temperature-variable material.

6. The hydrogen leakage monitoring system according to claim 5, characterized in that: The grinding is performed using a ball mill for 12-20 hours.

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