Monatomic catalyst for dehydrogenation of liquid organic hydrogen carrier, and preparation method therefor and use thereof

Abstract

A monatomic catalyst for dehydrogenation of a liquid organic hydrogen carrier, and a preparation method therefor and the use thereof. The monatomic catalyst comprises a metal oxide carrier and precious-metal single atoms loaded on the oxide carrier. The obtained monatomic catalyst is applied to the process of a dehydrogenation reaction of a liquid organic hydrogen carrier; compared with metal particles, the monatomic catalyst exhibits better catalytic activity; moreover, the amount of precious metals used is effectively reduced, thereby reducing the cost of the catalyst.

Description

A single-atom catalyst for dehydrogenation of liquid organic hydrogen storage carrier and its preparation method and application Technical Field

[0001] The present application relates to the field of catalysis, for example, a single-atom catalyst for dehydrogenation of a liquid organic hydrogen storage carrier, and its preparation method and application. Background Art

[0002] Hydrogen energy, a promising renewable energy source, is gaining increasing attention in addressing the energy crisis. However, the safe storage and transportation of hydrogen pose significant challenges to its development. Liquid organic hydrogen storage carriers (LOHCs) are considered a key technology that can effectively address these challenges and potentially achieve carbon neutrality within decades.

[0003] LOHC is a method for storing and transporting hydrogen that utilizes the reversible reaction between unsaturated liquid organic compounds, such as alkenes, alkynes, or aromatic hydrocarbons, and hydrogen to achieve hydrogen storage (chemical bonding) and release. This technology utilizes hydrogenation to store hydrogen and dehydrogenation to release it. Its advantages include large hydrogen storage capacity, transportability at room temperature and pressure, and safety.

[0004] Specifically, in LOHC, hydrogen is chemically bonded to an organic hydrocarbon carrier molecule (hydrogenation) and can be released in the reverse process (dehydrogenation). Common LOHC systems include methylcyclohexane (MCH), monobenzyltoluene (MBT), dibenzyltoluene (DBT), or decahydronaphthalene / naphthol, which usually exist in liquid form under fairly relaxed standard conditions. Whether in hydrogenated or dehydrogenated form, it has similar physical properties to conventional fossil fuels (such as diesel).

[0005] LOHCs therefore offer numerous advantages. First, they can overcome the challenges of hydrogen transportation, leveraging existing infrastructure to transport and store hydrogen more efficiently, effectively, and safely. Compared to liquid hydrogen, LOHCs are non-flammable and less expensive to transport; liquid hydrogen is explosive, easily evaporates, and requires expensive containers and new, dedicated infrastructure. Second, LOHCs are highly pure and non-toxic. Unlike ammonia, which has safety and environmental concerns, LOHCs offer at least comparable reconversion costs and guaranteed purity. Furthermore, due to their physical similarities to conventional liquid fuels, LOHCs have the potential to be easily used and transported within existing infrastructure.

[0006] Clearly, LOHC has the potential to meet global hydrogen supply and demand, but its practical application and development are limited by the development of catalysts more suitable for large-scale production and application. Catalysts play an important role in the hydrogenation and dehydrogenation processes, not only reducing reaction temperatures but also improving the reaction rate of chemical hydrogen storage technology. In recent years, research on dehydrogenation catalysts for liquid organic hydrogen storage supports has primarily focused on precious metal catalysts. However, these technologies suffer from problems such as high precious metal loadings, uneven distribution of active components on the support, and easy agglomeration during the reaction, resulting in low reaction activity.

[0007] Therefore, a new solution needs to be developed to solve the problems of existing dehydrogenation catalysts, which is of great practical significance for the large-scale application and development of LOHC.

[0008] Summary of the Invention

[0009] The following is a summary of the subject matter described in detail herein. This summary is not intended to limit the scope of the claims.

[0010] This application provides a single-atom catalyst for the dehydrogenation of liquid organic hydrogen storage carriers, as well as its preparation method and application. The single-atom catalyst comprises a metal oxide carrier and single noble metal atoms supported on the oxide carrier. When applied to the dehydrogenation reaction of liquid organic hydrogen storage carriers, the single-atom catalyst exhibits superior catalytic activity compared to metal particles, effectively reduces the amount of noble metal used, and lowers catalyst cost.

[0011] In a first aspect, the present application provides a single-atom catalyst for dehydrogenation of a liquid organic hydrogen storage carrier, wherein the single-atom catalyst comprises a metal oxide carrier and a noble metal single atom supported on the oxide carrier.

[0012] This application constructs the single-atom catalyst and applies it to the dehydrogenation reaction process of a liquid organic hydrogen storage carrier. Compared with metal particles, the single-atom catalyst exhibits better catalytic activity and effectively reduces the amount of precious metals used, thereby reducing the cost of the catalyst.

[0013] The following are optional technical solutions for this application, but are not intended to limit the technical solutions provided in this application. Through the following technical solutions, the technical objectives and beneficial effects of this application can be better achieved and realized.

[0014] As an optional technical solution of the present application, the metal oxide support includes transition metal oxide and / or rare earth metal oxide.

[0015] In one embodiment, the metal oxide support includes any one of cerium oxide, titanium oxide, aluminum oxide or zirconium oxide, and can be cerium oxide.

[0016] The oxygen vacancies on the specific metal oxide carrier of the present application are more easily able to achieve single-atom loading, while compared with inert carriers that lack single-atom anchoring points, single-atom loading cannot be achieved after simple calcination treatment.

[0017] In one embodiment, the noble metal includes at least one of Pt, Pd or Rh. For example, typical but non-limiting combinations include a combination of Pt and Pd, a combination of Pt and Rh, or a combination of Pd and Rh.

[0018] In one embodiment, based on the mass of the metal oxide support as 100%, the loading amount of the noble metal single atom is 0.1% to 5%, for example, 0.1%, 0.5%, 0.8%, 1%, 1.2%, 1.4%, 1.6%, 1.8%, 2%, 2.2%, 2.4%, 2.6%, 2.8%, 3%, 3.2%, 3.4%, 3.6%, 3.8%, 4%, 4.2%, 4.4%, 4.6%, 4.8% or 5%, etc., but are not limited to the listed values, and other values ​​not listed within the above numerical range are also applicable.

[0019] In a second aspect, the present application provides a method for preparing the single-atom catalyst according to the first aspect, the preparation method comprising:

[0020] The metal oxide support is mixed with a noble metal precursor and activated to obtain a single atom catalyst.

[0021] Compared with related technologies, the present application can achieve single-atom dispersion of precious metals by a one-step impregnation method, significantly improving the utilization rate of active components, achieving low precious metal usage, improving the reaction activity of the catalyst, and effectively reducing the preparation cost of the catalyst.

[0022] As an optional technical solution of the present application, the mixing method includes performing incipient wetness impregnation of the metal oxide support in a solution of a noble metal precursor.

[0023] In one embodiment, the noble metal precursor includes at least one of tetraammine platinum nitrate, chloroplatinic acid, palladium chloride, rhodium chloride, tetraammine palladium nitrate, or rhodium nitrate.

[0024] As an optional technical solution of the present application, the method for preparing the metal oxide support includes:

[0025] The metal oxide precursor is calcined to obtain a metal oxide support.

[0026] In one embodiment, the metal oxide precursor comprises a nitrate of the corresponding metal.

[0027] In one embodiment, the metal oxide precursor comprises cerium nitrate.

[0028] In one embodiment, the calcination temperature is 400-600°C, for example, 400°C, 420°C, 440°C, 460°C, 480°C, 500°C, 520°C, 540°C, 560°C, 580°C or 600°C, and the calcination time is 3-5h, for example, 3h, 3.2h, 3.4h, 3.6h, 3.8h, 4h, 4.2h, 4.4h, 4.6h, 4.8h or 5h, etc., and is not limited to the listed values, and other values ​​not listed within the above numerical range are also applicable.

[0029] As an optional technical solution of the present application, drying and grinding treatments are performed before the activation treatment.

[0030] In one embodiment, the temperature of the activation treatment is 300-600°C, for example, 300°C, 320°C, 340°C, 360°C, 380°C, 400°C, 420°C, 440°C, 460°C, 480°C, 500°C, 520°C, 540°C, 560°C, 580°C or 600°C, etc., but is not limited to the listed values, and other unlisted values ​​within the above numerical range are also applicable.

[0031] In one embodiment, the activation treatment time is 120 to 240 minutes, for example, 120 minutes, 140 minutes, 160 minutes, 180 minutes, 200 minutes, 220 minutes or 240 minutes, but is not limited to the listed values. Other values ​​not listed within the above numerical range are also applicable.

[0032] In one embodiment, the activation treatment is performed under an inert atmosphere.

[0033] In one embodiment, the pressure condition of the activation treatment is 0.1 to 0.4 MPa, for example, 0.1 MPa, 0.12 MPa, 0.14 MPa, 0.16 MPa, 0.18 MPa, 0.2 MPa, 0.22 MPa, 0.24 MPa, 0.26 MPa, 0.28 MPa, 0.3 MPa, 0.32 MPa, 0.34 MPa, 0.36 MPa, 0.38 MPa or 0.4 MPa, etc., but is not limited to the listed values, and other unlisted values ​​within the above numerical range are also applicable.

[0034] The state of the noble metal loading is related to the calcination temperature and the reaction atmosphere during activation. In the preparation method described in this application, a noble metal single atom loading can be formed by performing an activation treatment at a specific temperature under an inert atmosphere, which simplifies the means of preparing single atoms.

[0035] As an optional technical solution of this application, the preparation method includes:

[0036] The metal oxide precursor is placed in a muffle furnace for calcination, wherein the metal oxide precursor includes a nitrate of the corresponding metal, and the nitrate includes cerium nitrate. The temperature is controlled at 400-600° C. and the time is 3-5 hours to obtain a metal oxide support.

[0037] preparing a noble metal precursor as an impregnation solution, wherein the noble metal precursor includes at least one of tetraammineplatinum nitrate or chloroplatinic acid;

[0038] Using the incipient wetness impregnation method, taking an appropriate amount of the impregnation solution, then adding the metal oxide support to the impregnation solution, stirring and standing, and then placing in an oven for drying to obtain a catalyst precursor loaded with precious metals;

[0039] The obtained catalyst precursor loaded with precious metals is ground and then activated in a tube furnace at a controlled temperature of 300 to 600° C. with an inert atmosphere maintained at a pressure of 0.1 to 0.4 MPa for 120 to 240 minutes to obtain a single-atom catalyst.

[0040] In a third aspect, the present application provides an application of the single-atom catalyst described in the first aspect, wherein the application includes dehydrogenation of liquid organic hydrogen storage carriers and heterogeneous catalytic dehydrogenation.

[0041] As an optional technical solution of the present application, the method for dehydrogenating the liquid organic hydrogen storage carrier includes:

[0042] The liquid organic hydrogen storage carrier is mixed with the single-atom catalyst described in the first aspect to carry out a catalytic dehydrogenation reaction to obtain a dehydrogenation product.

[0043] As an optional technical solution of the present application, the molar amount of the noble metal single atom in the single atom catalyst accounts for 0.01% to 0.1% of the molar amount of the liquid organic hydrogen storage carrier, for example, 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.09% or 0.1%, etc., but is not limited to the listed values, and other values ​​not listed within the above numerical range are also applicable.

[0044] In one embodiment, the temperature of the catalytic dehydrogenation reaction is 200-400°C, for example, 200°C, 220°C, 240°C, 260°C, 280°C, 300°C, 320°C, 340°C, 360°C, 380°C or 400°C, but is not limited to the listed values. Other values ​​not listed within the above numerical range are also applicable.

[0045] In one embodiment, the catalytic dehydrogenation reaction time is 1 to 5 hours, for example, 1 hour, 1.5 hours, 2 hours, 2.5 hours, 3 hours, 3.5 hours, 4 hours, 4.5 hours or 5 hours, but is not limited to the listed values. Other values ​​not listed within the above numerical range are also applicable.

[0046] In one embodiment, the catalytic dehydrogenation reaction is carried out under an inert atmosphere.

[0047] In one embodiment, the pressure condition of the catalytic dehydrogenation reaction is 0.1 to 1 MPa, for example, 0.1 MPa, 0.2 MPa, 0.3 MPa, 0.4 MPa, 0.5 MPa, 0.6 MPa, 0.7 MPa, 0.8 MPa, 0.9 MPa or 1 MPa, but is not limited to the listed values. Other values ​​not listed within the above numerical range are also applicable.

[0048] In one embodiment, the liquid organic hydrogen storage carrier includes at least one of monobenzyltoluene, dibenzyltoluene, methylcyclohexane or ethylcarbazole.

[0049] It should be noted that the single-atom catalyst obtained in this application is not limited to dibenzyltoluene. Catalysts for aromatic ring dehydrogenation have a common characteristic: the greater the number of benzene rings, the greater the difficulty of dehydrogenation. Therefore, the single-atom catalyst obtained in this application is suitable for dibenzyltoluene, which also means that it is compatible with other low-benzene organic liquids. Therefore, common organic liquids such as methylcyclohexane, decahydronaphthalene, ethylcarbazole, and monobenzyltoluene can be dehydrogenated using the single-atom catalyst obtained in this application as a liquid organic hydrogen storage carrier.

[0050] Compared with the related technical solutions, this application has at least the following beneficial effects:

[0051] This application constructs the single-atom catalyst and applies it to the dehydrogenation reaction process of a liquid organic hydrogen storage carrier. Compared with metal particles, the single-atom catalyst exhibits better catalytic activity and effectively reduces the amount of precious metals used, thereby reducing the cost of the catalyst.

[0052] In particular, when the obtained single-atom catalyst is applied to the dehydrogenation reaction of fully hydrogenated dibenzyltoluene, the dehydrogenation degree of the single-atom catalyst of the present application is comparable to that of the classic Pt / Al2O3 catalyst, but the amount of precious metal used is correspondingly reduced, the utilization rate of the active component is improved, and the cost of the catalyst is reduced.

[0053] Still other aspects will become apparent upon reading and understanding the detailed description. DETAILED DESCRIPTION

[0054] The technical solution of this application is further explained below through specific implementation methods.

[0055] Those skilled in the art should understand that the embodiments are only intended to help understand the present application and should not be regarded as specific limitations of the present application.

[0056] Example 1

[0057] This embodiment provides a single-atom catalyst for dehydrogenation of a liquid organic hydrogen storage carrier. The preparation method of the single-atom catalyst includes:

[0058] The metal oxide precursor cerium nitrate was placed in a muffle furnace for calcination at 600°C for 2 hours to obtain a metal oxide support.

[0059] The noble metal precursor chloroplatinic acid is prepared as an impregnation solution;

[0060] Using the incipient wetness impregnation method, take an appropriate amount of the impregnation solution, then add the metal oxide support to the impregnation solution, stir evenly and let it stand for 12 hours, then place it in an oven at 120° C. for 12 hours to obtain a catalyst precursor loaded with precious metals;

[0061] The obtained catalyst precursor loaded with precious metals was ground and then activated in a tubular furnace. The temperature was controlled at 600°C and the N2 atmosphere was maintained at a pressure of 0.25 MPa for 180 minutes to obtain a single-atom catalyst with a single-atom Pt loading of 0.5%.

[0062] Example 2

[0063] This embodiment provides a single-atom catalyst for dehydrogenation of a liquid organic hydrogen storage carrier. The preparation method of the single-atom catalyst is exactly the same as that of Example 1, except that the activation treatment temperature is adjusted from 600°C to 300°C.

[0064] Example 3

[0065] This embodiment provides a single-atom catalyst for dehydrogenation of a liquid organic hydrogen storage carrier. The preparation method of the single-atom catalyst is exactly the same as that of Example 1, except that the activation treatment temperature is adjusted from 600°C to 400°C.

[0066] Example 4

[0067] This embodiment provides a single-atom catalyst for dehydrogenation of a liquid organic hydrogen storage carrier. The preparation method of the single-atom catalyst is exactly the same as that of Example 1, except that the activation treatment temperature is adjusted from 600°C to 500°C.

[0068] Example 5

[0069] This embodiment provides a single-atom catalyst for dehydrogenation of a liquid organic hydrogen storage carrier. The preparation method of the single-atom catalyst is exactly the same as that of Example 1, except that the activation treatment temperature is adjusted from 600°C to 650°C.

[0070] Example 6

[0071] This embodiment provides a single-atom catalyst for dehydrogenation of a liquid organic hydrogen storage carrier. The preparation method of the single-atom catalyst is exactly the same as that of Example 1, except that the mass concentration of the precious metal precursor is adjusted so that the single-atom Pt loading in the obtained single-atom catalyst is adjusted from 0.5% to 0.3%.

[0072] Example 7

[0073] This embodiment provides a single-atom catalyst for dehydrogenation of a liquid organic hydrogen storage carrier. The preparation method of the single-atom catalyst is exactly the same as that of Example 1, except that the mass concentration of the precious metal precursor is adjusted so that the single-atom Pt loading in the obtained single-atom catalyst is adjusted from 0.5% to 0.1%.

[0074] Example 8

[0075] This embodiment provides a single-atom catalyst for dehydrogenation of a liquid organic hydrogen storage carrier. The preparation method of the single-atom catalyst is exactly the same as that of Example 1, except that the mass concentration of the precious metal precursor is adjusted so that the single-atom Pt loading in the obtained single-atom catalyst is adjusted from 0.5% to 1%.

[0076] Example 9

[0077] This embodiment provides a single-atom catalyst for dehydrogenation of a liquid organic hydrogen storage carrier. The preparation method of the single-atom catalyst is exactly the same as that of Example 1, except that the metal oxide carrier is adjusted so that the catalyst carrier in the obtained single-atom catalyst is adjusted from CeO2 to ZrO2.

[0078] Example 10

[0079] This embodiment provides a single-atom catalyst for dehydrogenation of a liquid organic hydrogen storage carrier. The preparation method of the single-atom catalyst is exactly the same as that of Example 1, except that the metal oxide carrier is adjusted so that the catalyst carrier in the obtained single-atom catalyst is adjusted from CeO2 to TiO2.

[0080] Example 11

[0081] This embodiment provides a single-atom catalyst for dehydrogenation of a liquid organic hydrogen storage carrier. The preparation method of the single-atom catalyst is exactly the same as that of Example 1, except that the metal oxide carrier is adjusted so that the catalyst carrier in the obtained single-atom catalyst is adjusted from CeO2 to Al2O3.

[0082] Comparative Example 1

[0083] This comparative example provides a catalyst, and the activation treatment of the preparation method of the catalyst is:

[0084] The obtained catalyst precursor loaded with precious metals was ground and then activated in a tubular furnace. The temperature was controlled at 400°C, pure hydrogen (H2) was maintained at a pressure of 0.25 MPa for 60 minutes to obtain a catalyst loaded with aggregated Pt. Except for the above, other conditions were exactly the same as in Example 1.

[0085] Control group 1

[0086] This control group provides a catalyst, and the preparation method of the catalyst includes: using the incipient wetness impregnation method to impregnate Pt on the Al2O3 carrier, controlling the Pt loading amount to 1wt.%, and activating the catalyst obtained by impregnation in a tubular furnace under the same activation conditions as in Comparative Example 1, thereby obtaining a 1Pt / Al2O3 catalyst.

[0087] Application Example 1

[0088] This application example provides a method for dehydrogenating a liquid organic hydrogen storage carrier, the method comprising:

[0089] 0.8 g of the catalyst obtained in Example 1 was placed in a batch reactor containing 15 g of a liquid organic hydrogen storage carrier, fully hydrogenated dibenzyltoluene. The molar amount of the precious metal in the catalyst was controlled to be 0.037% of the molar amount of the liquid organic hydrogen storage carrier. Nitrogen was first introduced to replace the gas in the reaction system. After the air was evacuated, the pressure was maintained at atmospheric pressure (0.1 MPa). A programmed temperature controller was used for control. After reaching the set temperature of 290° C., the dehydrogenation reaction timing was started. The reaction was stopped after 3 hours of timing. After cooling to room temperature, the liquid product was taken for analysis. The analytical instrument was equipped with a chromatogram with a TCD detector for online detection to obtain data on the dehydrogenation product.

[0090] Application Example 2-11

[0091] Application Examples 2-11 respectively provide a method for dehydrogenating a liquid organic hydrogen storage carrier, wherein the catalysts of Examples 2-11 are used instead of the catalyst of Example 1, and the amount of the catalyst is adjusted to control the molar amount of the precious metal in the catalyst to 0.037% of the molar amount of the liquid organic hydrogen storage carrier, which is consistent with Application Example 1. Except for the above, other conditions are exactly the same as those in Application Example 1.

[0092] Comparative Application Example 1

[0093] This comparative application example provides a method for dehydrogenating a liquid organic hydrogen storage carrier, wherein the catalyst of Comparative Example 1 is used instead of the catalyst of Example 1, and the amount of the catalyst is adjusted to control the molar amount of the precious metal in the catalyst to 0.037% of the molar amount of the liquid organic hydrogen storage carrier, which is consistent with Application Example 1. Except for the above, other conditions are exactly the same as those of Application Example 1.

[0094] Comparative Application Example 2

[0095] This comparative application example provides a method for dehydrogenating a liquid organic hydrogen storage carrier. The method uses the catalyst of the control group 1 instead of the catalyst of Example 1, and keeps the amount of the catalyst unchanged at 0.8 g, so that the molar amount of the precious metal in the catalyst accounts for 0.075% of the molar amount of the liquid organic hydrogen storage carrier. Except for the above, other conditions are exactly the same as those in Application Example 1.

[0096] The dehydrogenation reaction results of the relevant catalysts are shown in Table 1 below.

[0097] Table 1

[0098] As can be seen from Table 1, in a batch reactor, the reaction temperature is 290°C and the reaction is carried out for 3 hours. Comparison of Application Example 1 and Comparative Application Example 1 shows that Application Example 1 has significant dehydrogenation activity, which also indicates that the state of the metal species determines the dehydrogenation activity: the dehydrogenation ability of single atoms is better than that of aggregated metal clusters; Application Examples 1-5 investigate the effect of activation treatment temperature on reaction activity. The high and low activation temperature affects the distribution ability of single atoms, and there is an optimal activation temperature. At a suitable activation temperature, it is beneficial to the single-atom level dispersion of metal species, but too low a reaction temperature leads to insufficient dispersion, while a higher reaction temperature easily leads to aggregation of active components; Application Examples 6-8 examine the effect of precious metal dosage on the dehydrogenation reaction activity, and there is also an optimal value for the metal loading: low metal dosage is insufficient for activating the reactants due to its overly dispersed active sites, while higher metal dosage restricts the dispersion ability of single atoms to a certain extent; Application Example 1 is compared with Application Examples 9-11. By examining the effect of different oxide supports on dehydrogenation activity, it is found that this scheme is applicable to different oxide supports and has high dehydrogenation activity; and compared with the control group 1 (classic Pt / Al2O3) catalyst, the dehydrogenation degree of the single-atom catalyst of this application is comparable to it, but the corresponding reduction in the amount of precious metal, the improvement of the utilization rate of the active components, and the reduction of the cost of the catalyst.

[0099] The present application uses the above-mentioned embodiments to illustrate the detailed structural features of the present application. However, the present application is not limited to the above-mentioned detailed structural features, that is, it does not mean that the present application must rely on the above-mentioned detailed structural features to be implemented. Those skilled in the art should understand that any improvements to the present application, equivalent replacements of selected components of the present application, addition of auxiliary components, selection of specific methods, etc., all fall within the scope of protection and disclosure of the present application.

[0100] The above describes in detail the optional implementation methods of the present application. However, the present application is not limited to the specific details of the above implementation methods. Within the technical concept of the present application, various simple modifications can be made to the technical solution of the present application, and these simple modifications all fall within the scope of protection of the present application.

[0101] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any appropriate manner unless there is any contradiction. In order to avoid unnecessary repetition, this application will not further describe various possible combinations.

[0102] In addition, the various implementation methods of the present application may be arbitrarily combined, and as long as they do not violate the concept of the present application, they should also be regarded as the contents disclosed in the present application.

Claims

1. A single-atom catalyst for dehydrogenation of a liquid organic hydrogen storage carrier, comprising a metal oxide carrier and a noble metal single atom supported on the oxide carrier.

2. The single-atom catalyst according to claim 1, wherein The metal oxide support includes transition metal oxide and / or rare earth metal oxide.

3. The single-atom catalyst according to claim 1 or 2, wherein The metal oxide support includes any one of cerium oxide, aluminum oxide or titanium oxide.

4. The single-atom catalyst according to any one of claims 1 to 3, wherein The noble metal includes at least one of Pt, Pd, or Rh.

5. The single-atom catalyst according to any one of claims 1 to 4, wherein Based on the mass of the metal oxide support being 100%, the loading amount of the noble metal single atom is 0.1% to 5%.

6. A method for preparing the single-atom catalyst according to any one of claims 1 to 5, comprising: The metal oxide support is mixed with a noble metal precursor and activated to obtain a single atom catalyst.

7. The method for preparing a single-atom catalyst according to claim 6, wherein: The mixing method includes incipient wetness impregnation of the metal oxide support into a solution of a noble metal precursor.

8. The method for preparing a single-atom catalyst according to claim 6 or 7, wherein: The noble metal precursor includes at least one of tetraammineplatinum nitrate or chloroplatinic acid.

9. The method for preparing a single-atom catalyst according to any one of claims 6 to 8, wherein: The method for preparing the metal oxide support comprises: calcining the metal oxide precursor to obtain a metal oxide support; Optionally, the metal oxide precursor comprises a nitrate of the corresponding metal; Optionally, the calcination temperature is 400-600° C., and the calcination time is 3-5 hours.

10. The method for preparing a single-atom catalyst according to any one of claims 6 to 9, wherein: Before the activation treatment, the material is first dried and ground; Optionally, the activation treatment temperature is 300-600°C; Optionally, the activation treatment time is 120 to 240 minutes; Optionally, the activation treatment is carried out under an inert atmosphere; Optionally, the pressure condition of the activation treatment is 0.1-0.4 MPa.

11. The method for preparing a single-atom catalyst according to any one of claims 6 to 10, comprising: The metal oxide precursor is placed in a muffle furnace for calcination, wherein the metal oxide precursor includes a nitrate of the corresponding metal, and the nitrate includes cerium nitrate. The temperature is controlled at 400-600° C. and the time is 3-5 hours to obtain a metal oxide support. preparing a noble metal precursor as an impregnation solution, wherein the noble metal precursor includes at least one of tetraammineplatinum nitrate or chloroplatinic acid; Using the incipient wetness impregnation method, taking an appropriate amount of the impregnation solution, then adding the metal oxide support to the impregnation solution, stirring and standing, and then placing in an oven for drying to obtain a catalyst precursor loaded with precious metals; The obtained catalyst precursor loaded with precious metals is ground and then activated in a tube furnace at a controlled temperature of 300 to 600° C. with an inert atmosphere maintained at a pressure of 0.1 to 0.4 MPa for 120 to 240 minutes to obtain a single-atom catalyst.

12. Use of the single-atom catalyst according to any one of claims 1 to 5, wherein: The applications include dehydrogenation of liquid organic hydrogen storage carriers.

13. Use of the single-atom catalyst according to claim 12, wherein: The method for dehydrogenating the liquid organic hydrogen storage carrier comprises: The liquid organic hydrogen storage carrier is mixed with the single-atom catalyst according to any one of claims 1 to 5, and a catalytic dehydrogenation reaction is carried out to obtain a dehydrogenation product.

14. Use of the single-atom catalyst according to claim 13, wherein: The molar amount of the noble metal single atom in the single atom catalyst accounts for 0.01% to 0.1% of the molar amount of the liquid organic hydrogen storage carrier; Optionally, the temperature of the catalytic dehydrogenation reaction is 200-400°C; Optionally, the catalytic dehydrogenation reaction time is 1 to 5 hours; Optionally, the catalytic dehydrogenation reaction is carried out under an inert atmosphere; Optionally, the pressure condition of the catalytic dehydrogenation reaction is 0.1-1 MPa.

15. Use of the single atom catalyst according to claim 13 or 14, wherein: The liquid organic hydrogen storage carrier includes at least one of monobenzyltoluene, dibenzyltoluene, methylcyclohexane or ethylcarbazole.

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