Gold-loaded alkane dehydrogenation catalyst as well as preparation method and application thereof

Abstract

The invention relates to the technical field of catalysts, and discloses a gold-loaded alkane dehydrogenation catalyst and a preparation method and application thereof.The core of the catalyst is a ZMQ-1 molecular sieve, gold nanoparticles are evenly loaded on the titanium-doped ZMQ-1 molecular sieve, and a nano carbon material serves as an auxiliary material to optimize the stability and dispersity of the catalyst; the preparation method comprises the following steps: synthesizing a titanium-doped ZMQ-1 molecular sieve, preparing a functionalized carbon nanomaterial, loading gold particles and finally roasting the catalyst. In an alkane dehydrogenation reaction, the catalyst shows relatively high alkane conversion rate and olefin selectivity, and can maintain relatively good stability in multiple cycles. Compared with the prior art, the catalyst disclosed by the invention has excellent catalytic efficiency and long-term effect under a high-temperature condition, and is suitable for industrial application of alkane dehydrogenation reaction.

Description

Technical Field

[0001] The present invention relates to the technical field of catalysts, and particularly to a supported gold alkane dehydrogenation catalyst, a preparation method thereof, and an application thereof. Background Art

[0002] In the current field of alkane dehydrogenation catalysis, gold-based catalysts have become a research hotspot due to their excellent catalytic performance and high reaction selectivity. However, although gold nanoparticles have excellent catalytic performance in alkane dehydrogenation reactions, existing catalysts still face problems such as poor dispersion of gold particles, reduced catalytic activity, and insufficient stability of the catalysts under high-temperature conditions. Traditional methods for loading gold particles, such as the impregnation method, often have difficulty in controlling the particle size and distribution of gold particles, resulting in the aggregation of gold particles, which in turn affects the active sites and reaction efficiency of the catalyst. In addition, gold particles are prone to sintering or desorption during high-temperature reactions, leading to a decrease in the activity and selectivity of the catalyst, severely limiting its industrial application.

[0003] In addition, most of the existing catalyst carriers have problems such as inappropriate pore sizes and weak acidity, which cannot effectively promote the adsorption and activation of reactants, thus affecting the conversion rate and reaction selectivity of alkanes. Especially at high temperatures, the stability of the carrier is poor, which may also lead to the decline of the catalyst. In addition, traditional catalysts often have difficulty in maintaining the high dispersion and stability of gold particles, resulting in a rapid decline in the activity of the catalyst during long-term use. Summary of the Invention

[0004] Aiming at the deficiencies of the prior art, the present invention provides a supported gold alkane dehydrogenation catalyst, a preparation method thereof, and an application thereof, which solve the problems of poor dispersion of gold particles, rapid decline of catalytic activity, and poor stability of the catalyst at high temperatures in existing gold-based catalysts.

[0005] To achieve the above objectives, the present invention is realized through the following technical solutions:

[0006] The first aspect of the present invention provides a supported gold alkane dehydrogenation catalyst, which includes the following components by weight percentage: 40% - 60% of ZMQ-1 molecular sieve, 1% - 5% of gold nanoparticles, 15% - 40% of nano-carbon materials, and 5% - 10% of metal-organic framework templates.

[0007] ZMQ-1 molecular sieve:

[0008] ZMQ-1 zeolite molecular sieve is a zeolite molecular sieve with a unique topological structure, having a super-large pore system and a mesopore system. As the framework material of the catalyst, it provides a large specific surface area and high pore volume, and can effectively adsorb alkane molecules and promote the occurrence of reactions. In the present invention, the content of ZMQ-1 zeolite molecular sieve is controlled between 40% and 60%, ensuring the stability of the catalyst, the selectivity of the catalytic reaction, and a long service life.

[0009] The characteristics of ZMQ-1 zeolite molecular sieve make it an ideal carrier for alkane dehydrogenation reaction. Its super-large pore system (such as 28-membered ring pores) can accommodate larger alkane molecules, thus providing sufficient space during the alkane dehydrogenation reaction, enabling the alkane to smoothly enter and react on the surface of gold particles. Due to the high surface area of the molecular sieve, it can also provide abundant active sites, effectively increasing the reaction rate and selectivity of the reaction.

[0010] The silicon and aluminum atoms in ZMQ-1 zeolite molecular sieve also provide additional acidic sites for the catalytic reaction, which helps to activate alkane molecules in the catalytic reaction.

[0011] Gold nanoparticles:

[0012] As the active component in this catalyst, gold nanoparticles are uniformly loaded on the surface of ZMQ-1 zeolite molecular sieve by atomic layer deposition (ALD), and the particle size is controlled between 2 and 5 nm. The loading amount of gold is controlled between 1% and 5% of the total mass of the catalyst to ensure the high efficiency of the catalytic reaction and prevent the aggregation of gold particles.

[0013] The activity of gold nanoparticles in the catalytic reaction mainly comes from their surface atoms. Gold has unique catalytic properties, especially in alkane dehydrogenation reaction, and can effectively promote the cleavage of C-H bonds in alkane molecules. On the surface of gold nanoparticles, the d orbitals of gold can interact with alkane molecules, resulting in the weakening of C-H bonds and finally realizing the dehydrogenation reaction.

[0014] By the atomic layer deposition (ALD) method, uniformly loading gold nanoparticles onto the surface of ZMQ-1 zeolite molecular sieve can ensure the uniform distribution of gold particles on the catalyst surface and a smaller particle size (2 - 5 nm). Smaller gold particles have higher surface energy, thus providing more reaction sites and enhancing the activity of the catalyst.

[0015] In addition, the electronic properties of gold nanoparticles can be adjusted by the surface electronic effect of the carrier ZMQ-1 zeolite molecular sieve, which further enhances the activity of gold particles in the catalytic reaction. By controlling the loading amount of gold, the reactivity of the catalyst can be optimized to avoid the aggregation phenomenon caused by excessive gold particles.

[0016] Nanocarbon materials:

[0017] As an auxiliary material for catalysts, carbon nanomaterials can enhance the electronic conductivity of catalysts and improve the dispersion of gold particles. The content of carbon nanomaterials is controlled between 15% and 40%, and they are treated by oxidation and nitrogen doping to increase their surface functional groups (such as carboxyl groups, amino groups, etc.).

[0018] Carbon nanomaterials, especially graphene and nitrogen-doped carbon nanotubes, have extremely high electronic conductivity and good thermal stability. Through oxidation treatment, hydrophilic functional groups (such as carboxyl groups, hydroxyl groups, etc.) are introduced onto the surface of carbon nanomaterials, which can form stronger interactions with gold particles, promote the uniform dispersion of gold particles, and prevent their aggregation during the reaction. Nitrogen-doped carbon nanotubes can provide more electron density, thereby enhancing the catalytic activity of gold particles.

[0019] In the alkane dehydrogenation reaction, carbon nanomaterials act as electron transfer media, which can improve the electronic conductivity and reaction rate of gold particles, and at the same time promote the stabilization of reaction intermediates. In addition, carbon nanomaterials can also prevent the sintering of gold particles at high temperatures and maintain their high surface activity.

[0020] Metal-organic framework templates:

[0021] The materials of metal-organic framework (MOF) templates are composed of metal centers (aluminum or titanium) and ligands (such as epoxy resins), which are used to assist in the loading of gold particles and ensure their uniform distribution. The content of MOF templates is controlled between 5% and 10%.

[0022] Metal-organic framework (MOF) materials have a highly ordered pore structure, which can provide uniform and stable sites for the loading of gold particles. The metal centers (such as aluminum or titanium) of MOF template materials form a framework structure by binding with ligands. This structure can not only guide gold precursors into the pores but also prevent the aggregation of gold particles during high-temperature reactions.

[0023] During the catalytic reaction process, MOF templates ensure the uniform distribution of gold particles through their unique pore structure and stability, and can effectively promote the contact between alkane molecules and gold particles. In addition, the interaction between the metal centers of MOF materials and gold particles can further improve the stability and catalytic activity of the catalyst.

[0024] The supported gold alkane dehydrogenation catalyst of the present invention innovatively combines ZMQ-1 molecular sieve, gold nanoparticles, nanocarbon materials, and metal-organic framework templates to form an efficient and stable catalytic system. The ZMQ-1 molecular sieve provides a high specific surface area and a suitable pore structure. The gold nanoparticles are uniformly loaded through atomic layer deposition technology and act synergistically with the nanocarbon materials, effectively improving the catalytic activity and the dispersion of gold particles, while preventing their aggregation. The metal-organic framework template further enhances the stability of gold particles through its unique pore structure and the action of metal centers, ensuring the long-term stability and high efficiency of the catalyst in high-temperature reactions. The design of this catalyst fully exploits the advantages of each component, significantly improving the efficiency and selectivity of the alkane dehydrogenation reaction, and having high industrial application potential.

[0025] Preferably, the nanocarbon material is graphene or nitrogen-doped carbon nanotubes, and their properties significantly enhance the overall performance of the catalyst. Specifically, the oxygen content of graphene is controlled between 10% and 25%, and the nitrogen doping ratio of nitrogen-doped carbon nanotubes is 1% to 5%.

[0026] As a nanocarbon material with high conductivity and excellent thermal stability, after oxidation treatment, some oxygen groups (such as carboxyl groups, hydroxyl groups, etc.) will be introduced on the surface of graphene. The oxygen content of graphene oxide is controlled between 10% and 25%, and these oxygen groups greatly enhance the hydrophilicity of graphene and its interaction ability with other materials (such as gold nanoparticles or ZMQ-1 molecular sieve). The introduction of oxygen groups makes the surface of graphene have stronger chemical activity, which can effectively form an electronic interaction with gold particles, ensuring the uniform dispersion of gold particles and preventing their aggregation.

[0027] Through the interaction between the surface oxygen groups of oxidized graphene and gold particles, the dispersion and stability of gold particles can be improved, avoiding the sintering phenomenon of gold particles in high-temperature reactions. The oxygen groups can also form a bond with the active sites on the surface of the ZMQ-1 molecular sieve, further enhancing the overall stability of the catalyst. In addition, the good conductivity of graphene helps the rapid transfer of electrons, thereby promoting the catalytic activity of gold particles and improving the efficiency of the alkane dehydrogenation reaction.

[0028] Nitrogen-doped carbon nanotubes (CNTs) are another important nanocarbon material, and their nitrogen doping ratio is controlled between 1% and 5%. Nitrogen doping can significantly change the electronic properties of carbon nanotubes, enhancing their conductivity and catalytic performance. Nitrogen atoms are located in the hexagonal carbon structure of carbon nanotubes, and they enhance the electron transfer ability of carbon nanotubes by providing additional electron density, thereby improving the electronic characteristics of gold particles in the catalyst. A stronger electronic coupling effect is formed between the nitrogen-doped carbon nanotubes and gold particles, thus promoting the catalytic activity of gold particles. Especially in the alkane dehydrogenation reaction, nitrogen-doped carbon nanotubes can improve the conversion rate and selectivity of the reaction.

[0029] Nitrogen-doped carbon nanotubes play two important roles in catalytic reactions. First, nitrogen doping can increase the affinity of carbon nanotubes, making the interaction between them and the surface of gold particles closer, effectively preventing the aggregation or sintering of gold particles at high temperatures. Second, the electron density introduced by nitrogen atoms enhances the electrical conductivity of carbon nanotubes, making them good electronic conductors, thereby promoting the electron transfer of gold particles and further enhancing the catalytic efficiency of gold nanoparticles. Through the synergistic effect formed with gold particles, nitrogen-doped carbon nanotubes can improve the stability of the catalyst and enhance the selectivity of alkane dehydrogenation reactions.

[0030] Generally speaking, graphene and nitrogen-doped carbon nanotubes provide better gold particle dispersion and enhance the catalytic performance of gold particles by increasing the electronic conductivity of the catalyst. The oxygen groups of graphene oxide and the nitrogen atoms of nitrogen-doped carbon nanotubes provide stronger interaction forces for gold particles, ensuring the stability of gold particles in high-temperature reactions and preventing their sintering, thereby improving the activity and selectivity of alkane dehydrogenation reactions. The synergistic effect of these mechanisms enables the catalyst to exhibit excellent catalytic performance and a long service life in practical applications.

[0031] Preferably, the average particle size of gold nanoparticles is 2 - 5 nm, and they are uniformly loaded on the surface of ZMQ-1 zeolite by atomic layer deposition (ALD). This design can effectively improve the catalytic activity and stability of the catalyst and optimize the selectivity of alkane dehydrogenation reactions.

[0032] The particle size of gold nanoparticles is controlled between 2 - 5 nm. This particle size range helps to maximize the surface area of gold particles, thus providing more active sites. The smaller the particle size of gold nanoparticles, the higher the proportion of surface atoms and the more active sites in catalytic reactions. Therefore, smaller gold particles have higher catalytic efficiency. Gold particles can interact with the C-H bonds in alkane molecules during catalytic reactions, thereby promoting dehydrogenation reactions.

[0033] Uniformly loading gold nanoparticles on the surface of ZMQ-1 zeolite by atomic layer deposition (ALD) can ensure the uniform distribution and high dispersion of gold particles. The ALD technique allows the deposition amount and particle size of gold particles to be controlled at the atomic level, so the size and distribution of gold particles can be precisely controlled, avoiding particle aggregation, thereby enhancing the stability and reaction activity of the catalyst.

[0034] The smaller particle size (2 - 5 nm) of gold nanoparticles ensures that more surface atoms participate in the catalytic reaction, thus having higher catalytic activity. Gold particles form active sites on the catalyst surface and interact with alkane molecules. Through the interaction between the d orbitals of gold and the C-H bonds in alkane molecules, the bond energy of the C-H bond is reduced, thereby realizing the dehydrogenation reaction of alkanes. Within this particle size range, the gold particles have high catalytic activity while avoiding aggregation or sintering of the gold particles, which is crucial for a stable reaction at high temperatures for a long time.

[0035] By loading gold nanoparticles through the ALD method, the loading amount, distribution, and particle size of gold particles can be precisely controlled on the surface of the molecular sieve, which ensures the high dispersion of gold particles. In the ALD process, by controlling the precise supply of gold precursors during each deposition, gold atoms can be deposited layer by layer, ensuring that the gold particles are evenly distributed and have consistent sizes. This uniformly distributed gold particles improves the reaction efficiency of the catalyst and significantly reduces the possibility of particle agglomeration under high-temperature reaction conditions. The ALD technique can also avoid the overloading of gold particles, further improving the stability and long-term performance of the catalyst.

[0036] Generally speaking, the designed controlled particle size of gold nanoparticles and their uniform loading on the surface of ZMQ-1 molecular sieve by the ALD method ensure the high activity and stability of the catalyst. The smaller particle size of gold particles endows them with stronger catalytic activity, while the ALD method ensures the high dispersion and uniformity of gold particles, preventing particle aggregation or sintering, thus significantly improving the efficiency and selectivity of the alkane dehydrogenation reaction, and at the same time enhancing the long-term stability of the catalyst.

[0037] Preferably, in the metal-organic framework (MOF) template material, the metal center is aluminum or titanium, and its ligand is epoxy resin. The design of the MOF template is to provide a stable support structure for precisely loading gold particles and ensuring their uniform distribution in the reaction.

[0038] The metal-organic framework (MOF) material is composed of a metal center (such as aluminum or titanium) and an organic ligand (such as epoxy resin). In the present invention, the metal center can be selected from aluminum or titanium, which play a key role in the catalytic process. Aluminum and titanium as metal centers have strong chemical stability and high-temperature resistance, enabling the MOF template to withstand high-temperature environments in the alkane dehydrogenation reaction without losing its structural integrity.

[0039] As the ligand of MOF, the oxygen atoms and nitrogen atoms in the molecular structure of epoxy resin can form a stable coordination structure with the metal center, thus providing good structural stability and pore structure. As an organic ligand, epoxy resin has high thermal stability and chemical stability, and can provide a microenvironment suitable for the loading of gold particles.

[0040] Metal-organic frameworks (MOFs) templates play two main roles in the preparation of catalysts through the coordination of their stable metal centers and organic ligands. On the one hand, MOF materials provide a highly ordered pore structure, which can effectively guide the uniform deposition of gold particles, ensuring the dispersion and stability of gold particles. On the other hand, the metal-metal interaction formed between the metal centers (aluminum or titanium) and gold particles can further enhance the stability of the catalyst and improve the selectivity of the catalytic reaction.

[0041] The metal centers of aluminum or titanium form a stable MOF structure through coordination with epoxy resin ligands. This stable framework can prevent the aggregation or sintering of gold particles under high-temperature conditions and at the same time provide a stable pore system, which is crucial for efficient catalytic reactions. The pores of MOF materials not only provide loading positions for gold particles but also control the size and distribution of gold particles through their fine pore structures, avoiding the excessive aggregation of gold particles and improving the efficiency of catalytic reactions.

[0042] As a ligand, epoxy resin can coordinate with metal centers through its functional groups, thus providing an ideal support structure for the loading of gold particles. Through this coordination, epoxy resin can form a microenvironment in MOF materials, which helps to stabilize the dispersed state of gold particles and reduce the agglomeration of gold particles.

[0043] In the present invention, the metal-organic framework (MOF) template provides a highly stable and ordered structure through the synergistic effect of aluminum or titanium metal centers and epoxy resin ligands, ensuring that gold particles can be uniformly loaded and stably dispersed. This MOF template not only enhances the structural stability of the catalyst but also optimizes the distribution of gold particles through its pore system, preventing the aggregation of gold particles, thereby significantly improving the activity and selectivity of the catalytic reaction. This design enables the catalyst to maintain stability at high temperatures and exhibit excellent catalytic performance in the dehydrogenation reaction of alkanes.

[0044] Preferably, the ZMQ-1 molecular sieve has a 28-membered ring pore system, and the size range of the pores is And 5% - 15% of titanium element is doped in the molecular sieve, and the titanium source of the titanium element is tetrabutyl titanate or isopropyl titanate. This design significantly optimizes the structure and performance of the catalyst and improves its catalytic activity and selectivity in the dehydrogenation reaction of alkanes.

[0045] The ZMQ-1 molecular sieve has a 28-membered ring pore system, and the size of its pores is controlled within Between them. The size of the 28-membered ring pore channels enables the molecular sieve to have sufficiently large pore channels, capable of effectively processing larger molecular substrates, such as alkanes, especially alkanes with 6 or more carbon atoms. In the alkane dehydrogenation reaction, the size of the molecular sieve pore channels determines whether the reactants can smoothly enter the catalytic sites. Therefore, a molecular sieve with an appropriate pore diameter can enhance the contact and catalytic activity of the reactants.

[0046] The size of the 28-membered ring pore channel system ( ) not only enables alkane molecules to easily enter the pore channels of the molecular sieve but also effectively guides the reactants to the vicinity of the gold particles, thereby accelerating the dehydrogenation reaction of alkanes. The larger pore channels ensure that the molecular sieve can accommodate larger molecular alkanes during the catalytic process, avoiding excessive restriction on small molecular substrates. In addition, the structure of the molecular sieve can provide abundant reaction sites, which help to improve the efficiency and selectivity of the catalytic reaction.

[0047] In the alkane dehydrogenation reaction, the 28-membered ring pore channels of the ZMQ-1 molecular sieve can accommodate alkane molecules and interact with the gold particles. The gold particles, as the active sites of the reaction, promote the dehydrogenation of alkanes, ultimately producing olefin products. This molecular sieve structure with an appropriate pore diameter plays a key role in improving the catalytic effect and reaction selectivity of the catalyst.

[0048] 5% to 15% of titanium element is incorporated into the ZMQ-1 molecular sieve, and the source of the titanium element is tetrabutyl titanate or isopropyl titanate. Titanium doping can not only improve the acidity of the ZMQ-1 molecular sieve but also enhance the stability and activity of the catalyst. The incorporation of titanium as a metal element enhances the acidity of the molecular sieve, providing more acidic sites, which helps the adsorption and activation of alkanes, thereby promoting the dehydrogenation reaction.

[0049] The incorporation of titanium has an important impact on the structure and catalytic performance of the ZMQ-1 molecular sieve. The titanium element replaces some aluminum or silicon sites in the ZMQ-1 molecular sieve, enhancing the acidity of the molecular sieve and forming stronger acidic sites, which can effectively adsorb and activate alkane molecules. By increasing the acidic sites, titanium doping enhances the affinity of the catalyst for alkanes and promotes the dehydrogenation reaction of alkanes.

[0050] The stability of the titanium-doped ZMQ-1 molecular sieve at high temperatures is also improved. Titanium, as a metal element with high-temperature stability, can effectively improve the anti-sintering ability of the catalyst under high-temperature reaction conditions, ensure the dispersion of gold particles, and prevent the aggregation of gold particles at high temperatures. In addition, the titanium element adjusts the electronic structure of the gold particles through the electronic effect, thereby improving the catalytic activity of the gold particles.

[0051] The 28-membered ring pore channel system of the ZMQ-1 molecular sieve ( ) It provides pores large enough to effectively accommodate larger - molecule alkane substrates, thereby enhancing the catalytic activity and selectivity of the catalyst. By doping 5% - 15% of titanium elements into the ZMQ - 1 molecular sieve, the acidity and stability of the molecular sieve are further improved, while the dispersion of gold particles is also improved, enhancing the efficiency of the catalytic reaction. The doping of titanium and the design of pores complement each other, significantly enhancing the catalytic performance of the catalyst, especially its stability and long - term effectiveness at high temperatures.

[0052] The second aspect of the present invention provides a method for preparing the supported gold alkane dehydrogenation catalyst, comprising the following steps:

[0053] (1) Synthesize the ZMQ - 1 molecular sieve and add a titanium source during its synthesis to obtain a titanium - doped ZMQ - 1 molecular sieve;

[0054] Tetraethoxysilane (TEOS) is used as the silicon source, aluminum nitrate is used as the aluminum source, and dimethyldisilane or organic amines are used as the template agent for the synthesis of the ZMQ - 1 molecular sieve. The crystallization temperature is controlled at 150 - 250 °C, and the crystallization time is 12 - 36 hours. The titanium source (such as tetrabutyl titanate or isopropyl titanate) is added during the synthesis of the molecular sieve, so that 5% - 15% of titanium elements are doped into the ZMQ - 1 molecular sieve.

[0055] The synthesis process of the ZMQ - 1 molecular sieve generates a molecular sieve framework with a specific structure by using a silicon source and an aluminum source. The incorporation of titanium, by substituting some silicon or aluminum atoms, makes the molecular sieve have stronger acidity and higher thermal stability. Titanium elements, as doping elements in the molecular sieve framework, enhance the structural stability of the ZMQ - 1 molecular sieve, improve the high - temperature resistance of the catalytic reaction, and at the same time increase the adsorption ability and activation ability for alkane substrates. During this process, the role of the template agent is to help generate the pore structure of the molecular sieve, ensuring that the molecular sieve can effectively accommodate larger - molecule substrates in the catalytic reaction.

[0056] (2) Perform oxidation treatment and nitrogen - doping treatment on graphene or carbon nanotubes to obtain a functionalized nanocarbon material;

[0057] After the oxidation treatment of graphene or carbon nanotubes, oxygen groups (such as carboxyl, hydroxyl, etc.) are introduced on the surface, and their electronic properties are improved through nitrogen - doping treatment. The oxygen content of the oxidized graphene is controlled at 10% - 25%, and the nitrogen - doping ratio of the nitrogen - doped carbon nanotubes is controlled at 1% - 5%.

[0058] The treatment of graphene oxide and nitrogen-doped carbon nanotubes can significantly enhance their interaction with gold particles. The introduction of oxygen groups makes the graphene surface more hydrophilic and has stronger chemical activity, enabling it to form a stable chemical bond with gold particles and preventing the aggregation of gold particles during the reaction. Nitrogen doping can increase the electron density of carbon nanotubes, making them better electron conductors, thereby enhancing the catalytic activity of gold particles. In addition, the additional electron density provided by nitrogen-doped carbon nanotubes can enhance the electron transfer ability of gold particles, further improving the catalytic efficiency in the dehydrogenation reaction of alkanes.

[0059] (3) Load the gold precursor using the metal-organic framework template method and obtain gold nanoparticles through thermal reduction.

[0060] The gold precursor is chloroauric acid or gold trichloride, and the gold nanoparticles are loaded by the metal-organic framework (MOF) template method. The thermal reduction process is carried out at a temperature of 150 - 200 °C.

[0061] The role of the metal-organic framework (MOF) template is to provide a stable pore structure and coordination environment, enabling the gold precursor (such as chloroauric acid or gold trichloride) to be uniformly dispersed and deposited within the MOF pores. Through the thermal reduction method, the gold precursor is reduced to gold nanoparticles. This process ensures that the size of the gold particles is controlled between 2 - 5 nm and avoids particle aggregation. During the reduction process, the gold precursor is reduced to metallic gold, and the gold particles remain uniformly distributed within the MOF template. The pore structure of the MOF not only helps in the dispersion of gold particles but also enhances the catalytic activity through the metal-support interaction.

[0062] (4) Load the gold nanoparticles onto the titanium-doped ZMQ-1 molecular sieve, and add the functionalized nanocarbon material to the composite catalyst through physical mixing or solvent treatment to obtain the final catalyst.

[0063] The gold nanoparticles are uniformly loaded onto the titanium-doped ZMQ-1 molecular sieve through physical mixing or solvent treatment, and then the functionalized nanocarbon material is added to the composite catalyst, finally forming the catalyst.

[0064] The methods of physical mixing or solvent treatment can ensure the uniform distribution of gold nanoparticles on the surface of the titanium-doped ZMQ-1 molecular sieve, which helps to increase the number of active sites in the catalytic reaction and prevent the aggregation of gold particles during the reaction. The addition of nanocarbon materials (such as functionalized graphene or nitrogen-doped carbon nanotubes) further enhances the stability and conductivity of the catalyst. Nanocarbon materials can help the gold particles maintain good dispersion, avoid their sintering at high temperatures, and at the same time enhance the interaction between the gold particles and the ZMQ-1 molecular sieve.

[0065] (5) Calcinate the final catalyst at a temperature of 500 - 600 °C to remove residual organic substances and optimize the binding between gold particles and the support;

[0066] The obtained final catalyst is calcined at a temperature of 500 - 600 °C to remove residual organic substances and solvents, and at the same time optimize the binding between gold particles and the support (ZMQ-1 zeolite and nano-carbon material).

[0067] The calcination process can remove excess organic substances in the catalyst and ensure a strong binding between gold particles and the support. Through high-temperature calcination, gold particles can further form a stronger metal-support interaction with the surface of ZMQ-1 zeolite, thereby improving the stability and activity of the catalyst. The calcination process can also remove solvents or unreacted organic substances to ensure the high purity and high efficiency of the catalyst under high-temperature conditions.

[0068] Through the above steps, the preparation method of the gold-loaded alkane dehydrogenation catalyst of the present invention ensures the uniform distribution and dispersion of gold nanoparticles, and at the same time optimizes the structure of the catalyst, making it have excellent catalytic performance and long-term stability in the alkane dehydrogenation reaction. ZMQ-1 zeolite provides an ideal pore structure and reaction sites, titanium doping improves the acidity and stability of the catalyst, and the functionalized nano-carbon material further enhances the dispersion and reaction activity of gold particles. By precisely controlling the conditions of each step, a gold-loaded catalyst with high catalytic efficiency and excellent stability is finally obtained.

[0069] In the third aspect of the present invention, an application of the gold-loaded alkane dehydrogenation catalyst is provided, especially its application in the alkane dehydrogenation reaction. Under the conditions of a reaction temperature of 550 - 700 °C, a hydrogen concentration of 1% - 10%, and a reaction time of 1 - 6 hours, this application can effectively convert alkanes into olefin products.

[0070] In the alkane dehydrogenation reaction, temperature is the key factor determining the reaction rate and selectivity. The temperature range of 550 - 700 °C provides sufficient thermal energy for the reaction, prompting the cleavage of C-H bonds in alkane molecules. A higher temperature is beneficial to enhancing the catalytic activity of gold particles and accelerating the dehydrogenation reaction of alkanes. The catalytic activity of gold particles is effectively exerted within this temperature range, and gold particles will not be over-sintered or deactivated due to excessive temperature. By adjusting the temperature, the efficiency and selectivity of the dehydrogenation reaction can be optimized, and side reactions can be avoided.

[0071] The concentration of hydrogen directly affects the process of alkane dehydrogenation. Within this concentration range, the presence of hydrogen helps to maintain the reduced state of the catalyst and avoid the oxidation of gold particles. Hydrogen not only participates in the hydrogenation process in the reaction but also can regulate the surface properties of gold particles and enhance their catalytic activity. In addition, an appropriate hydrogen concentration can effectively control the selective dehydrogenation of alkanes and avoid the formation of by-products. Excessive hydrogen concentration may lead to side reactions such as cracking or hydrogenation reactions. Therefore, the concentration range of 1% - 10% is the optimal condition selected in the present invention.

[0072] The control of the reaction time is crucial for the activity and stability of the catalyst. Within the reaction time range of 1 - 6 hours, the catalyst can effectively promote the dehydrogenation reaction of alkanes while avoiding the decline of the catalyst's active sites or the overreaction of reactants caused by too long reaction time. A shorter reaction time may lead to incomplete reactions, while too long a reaction time may lead to the cracking of olefin products or the formation of other by-products. Therefore, controlling the reaction time within 1 - 6 hours can ensure that the catalytic reaction proceeds at a higher conversion rate while maintaining good selectivity.

[0073] In the application of the present invention, the catalytic mechanism of the supported gold alkane dehydrogenation catalyst mainly includes the following aspects:

[0074] 1. Catalytic action of gold nanoparticles:

[0075] Gold nanoparticles interact with alkane molecules through their surface atoms, promoting the cleavage of C - H bonds. Due to the small particle size of gold particles (2 - 5 nm), they provide more active sites at high temperatures and can effectively promote the dehydrogenation reaction. In addition, the surface of gold particles can have an electronic interaction with hydrogen molecules, maintaining the reduced state of gold particles and enhancing the progress of the catalytic reaction.

[0076] 2. Role of ZMQ - 1 molecular sieve:

[0077] As a carrier, ZMQ - 1 molecular sieve provides a rich support surface and space for gold particles. Its 28 - membered ring pore system can effectively accommodate larger alkane molecules and guide them to the catalytic active sites of gold particles. The acidic sites of the molecular sieve enhance the adsorption ability of alkanes and promote the dehydrogenation reaction of alkane molecules on the surface of gold particles.

[0078] 3. Synergistic effect of nanocarbon materials:

[0079] Functionalized nanocarbon materials (such as graphene oxide or nitrogen - doped carbon nanotubes) enhance the stability of the catalyst by improving the dispersion of gold particles and preventing their aggregation. In addition, the good conductivity of nanocarbon materials helps electrons to be rapidly transferred between gold particles and ZMQ - 1 molecular sieve, further enhancing the catalytic activity of gold particles.

[0080] 4. Role of hydrogen:

[0081] In the alkane dehydrogenation reaction, hydrogen not only provides the necessary hydrogen source for the reaction, but also maintains its catalytic activity by reducing the surface oxide of gold particles. In the dehydrogenation reaction, the presence of hydrogen helps to stabilize the surface of gold particles, prevent the sintering of gold particles, and thus maintain the high efficiency of the catalyst.

[0082] In the temperature range of 550 - 700 °C, using a hydrogen concentration of 1% - 10% and a reaction time of 1 - 6 hours, the gold-loaded alkane dehydrogenation catalyst can efficiently promote the dehydrogenation reaction of alkanes to produce olefin products with high yields. The catalytic activity of gold nanoparticles is fully exerted under these reaction conditions. ZMQ-1 molecular sieve provides an ideal pore structure to support the adsorption and catalysis of reactants. The introduction of nano-carbon materials enhances the dispersion and stability of gold particles, and hydrogen ensures the reduced state and catalytic activity of gold particles. All these factors work together to ensure the high efficiency, selectivity, and long-term stability of the catalytic reaction.

[0083] The present invention provides a gold-loaded alkane dehydrogenation catalyst, its preparation method and application. It has the following beneficial effects:

[0084] 1. The present invention adopts a gold-loaded alkane dehydrogenation catalyst, in which gold nanoparticles are uniformly loaded on the surface of ZMQ-1 molecular sieve by atomic layer deposition method, and the particle size is controlled within 2 - 5 nm. This technical solution significantly improves the dispersion of gold particles and the efficiency of catalytic reaction. Compared with the commonly used gold loading methods in the prior art, the present invention effectively avoids the aggregation problem of gold particles, ensuring the stability and high efficiency of the catalyst at high temperatures.

[0085] 2. The present invention uses ZMQ-1 molecular sieve as the carrier of the catalyst, and 5% - 15% of titanium element is introduced during its synthesis. Through this titanium doping design, the acidity of the catalyst is significantly enhanced, improving the adsorption and activation ability of alkanes. Compared with the catalysts with traditional molecular sieve carriers, the titanium-doped ZMQ-1 molecular sieve of the present invention has obvious advantages in improving catalytic activity and high-temperature stability.

[0086] 3. The present invention combines functionalized nano-carbon materials (such as graphene oxide or nitrogen-doped carbon nanotubes) with gold nanoparticles to enhance the stability and conductivity of the catalyst. This technical solution effectively prevents the sintering of gold particles during the reaction process and improves the long-term service life of the catalyst. Compared with the prior art, the introduction of nano-carbon materials in the present invention significantly improves the stability of the catalyst under high temperature and high reaction conditions.

[0087] 4. The present invention adopts precisely controlled alkane dehydrogenation reaction conditions, which are carried out in the temperature range of 550 - 700 °C, the hydrogen concentration is 1% - 10%, and the reaction time is 1 - 6 hours. By optimizing the reaction conditions, the present invention significantly improves the alkane conversion rate and the selectivity of olefins. Compared with the fixed reaction conditions widely used in the prior art, the condition optimization of the present invention provides higher reaction efficiency and effectively reduces the generation of by-products. Detailed implementation manners

[0088] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0089] Example 1:

[0090] 1. Synthesis of ZMQ-1 molecular sieve:

[0091] Silicon source: 40% tetraethyl orthosilicate (TEOS), aluminum source: 2% aluminum nitrate, template agent: 4% dimethyldisilane, titanium source: 4% tetrabutyl titanate.

[0092] Add water and sodium hydroxide solution, adjust the pH to 10, set the crystallization temperature at 200 °C, and the crystallization time is 24 hours.

[0093] 2. Treatment of nano-carbon materials:

[0094] Oxidation treatment of graphene: Use a mixed solution of concentrated nitric acid (HNO3) and hydrogen peroxide (H2O2), react at 100 °C for 4 hours, and control the oxygen content at 20%.

[0095] Then carry out nitrogen doping: Treat in an ammonia atmosphere at 700 °C, and the nitrogen doping ratio is 3%.

[0096] 3. Loading of gold nanoparticles:

[0097] Use chloroauric acid as the gold precursor, load gold by the metal-organic framework (MOF) template method, and carry out thermal reduction at 150 °C to obtain gold nanoparticles with a particle size of 3 nm.

[0098] 4. Loading and compounding of gold particles:

[0099] Load the gold nanoparticles onto the titanium-doped ZMQ-1 molecular sieve, and use solvent treatment to compound the functionalized graphene with the molecular sieve to obtain the final catalyst.

[0100] 5. Calcination treatment:

[0101] The final catalyst was calcined at a temperature of 550 °C for 4 hours to remove residual organic matter and optimize the binding of gold particles to the support.

[0102] Example 2:

[0103] 1. Synthesis of ZMQ-1 zeolite:

[0104] Silicon source: tetraethyl orthosilicate (TEOS) 42%, aluminum source: aluminum nitrate 3%, templating agent: organic amine 3%, titanium source: titanium isopropoxide 5%.

[0105] Water was added and the pH was adjusted to 9. The crystallization temperature was 180 °C and the crystallization time was 18 hours.

[0106] 2. Treatment of nano-carbon materials:

[0107] Nitrogen doping treatment of nitrogen-doped carbon nanotubes: treated with ammonia gas at 800 °C, and the nitrogen doping ratio was 4%.

[0108] 3. Loading of gold nanoparticles:

[0109] Using gold trichloride as the gold precursor, loading was carried out by the metal-organic framework (MOF) templating method, and the temperature was controlled at 180 °C to obtain gold nanoparticles with a particle size of 2.5 nm.

[0110] 4. Loading and composite of gold particles:

[0111] The gold particles were loaded onto titanium-doped ZMQ-1 zeolite and compounded with functionalized nitrogen-doped carbon nanotubes by physical mixing to obtain the final catalyst.

[0112] 5. Calcination treatment:

[0113] The final catalyst was calcined at a temperature of 600 °C for 3 hours to remove residual organic matter and optimize the binding of gold particles to the support.

[0114] Example 3:

[0115] 1. Synthesis of ZMQ-1 zeolite:

[0116] Silicon source: tetraethyl orthosilicate (TEOS) 45%, aluminum source: aluminum nitrate 3%, templating agent: dimethyldisilane 4%, titanium source: titanium butoxide 6%.

[0117] Water and sodium hydroxide solution were used to adjust the pH to 9. The crystallization temperature was 220 °C and the crystallization time was 30 hours.

[0118] 2. Treatment of nano-carbon materials:

[0119] Graphene oxidation: Treated with concentrated nitric acid and hydrogen peroxide at 120 °C for 4 hours, and the oxygen content was controlled at 25%.

[0120] Nitrogen doping: Treated in ammonia gas at 600 °C, and the nitrogen doping ratio was 2%.

[0121] 3. Loading of gold nanoparticles:

[0122] Using chloroauric acid as the gold precursor, gold was loaded by the metal-organic framework (MOF) templating method and thermally reduced at 200 °C to obtain gold nanoparticles with a particle size of 4 nm.

[0123] 4. Loading and compounding of gold particles:

[0124] The gold particles were loaded onto titanium-doped ZMQ-1 zeolite, and the functionalized graphene oxide was compounded with the zeolite by solvent treatment to obtain the final catalyst.

[0125] 5. Calcination treatment:

[0126] Calcined at a temperature of 530 °C for 5 hours to remove excess organic matter and optimize the binding of gold particles to the carrier.

[0127] Example 4:

[0128] 1. Synthesis of ZMQ-1 zeolite:

[0129] Silicon source: 48% tetraethyl orthosilicate (TEOS), aluminum source: 2% aluminum nitrate, template agent: 2% dimethyldisilane, titanium source: 8% isopropyl titanate.

[0130] Water was added and the pH was adjusted to 8. The crystallization temperature was 190 °C and the crystallization time was 24 hours.

[0131] 2. Treatment of nanocarbon materials:

[0132] Nitrogen-doped carbon nanotubes: Treated in ammonia gas at 750 °C, and the nitrogen doping ratio was 3%.

[0133] 3. Loading of gold nanoparticles:

[0134] Using gold trichloride as the precursor, gold was loaded by the metal-organic framework (MOF) templating method, and the temperature was controlled at 160 °C to obtain gold nanoparticles with a particle size of 3.5 nm.

[0135] 4. Loading and compounding of gold particles:

[0136] The gold particles were loaded onto titanium-doped ZMQ-1 zeolite, and the functionalized nitrogen-doped carbon nanotubes were added to the catalyst by physical mixing to obtain the final catalyst.

[0137] 5. Calcination treatment:

[0138] The final catalyst was calcined at 600 °C for 4 hours to remove residual organic matter and optimize the binding of gold particles to the support.

[0139] Example 5:

[0140] 1. Synthesis of ZMQ-1 zeolite:

[0141] Silicon source: 50% tetraethyl orthosilicate (TEOS), aluminum source: 2% aluminum nitrate, templating agent: 3% organic amines, titanium source: 5% tetrabutyl titanate.

[0142] The pH was adjusted to 10 using water, the crystallization temperature was 210 °C, and the crystallization time was 20 hours.

[0143] 2. Treatment of nanocarbon materials:

[0144] Graphene oxidation: Using concentrated nitric acid and hydrogen peroxide, reacting at 110 °C for 5 hours, with the oxygen content controlled at 18%.

[0145] Nitrogen doping: Heating to 700 °C in an ammonia atmosphere, with the nitrogen doping ratio of 4%.

[0146] 3. Loading of gold nanoparticles:

[0147] Chloroauric acid was used as the gold precursor, and gold was loaded by the metal-organic framework (MOF) templating method and thermally reduced at 180 °C. The particle size of the gold particles was 4.5 nm.

[0148] 4. Loading and composite of gold particles:

[0149] The gold particles were loaded onto titanium-doped ZMQ-1 zeolite, and functionalized graphene was composited with the zeolite using a solvent treatment method to obtain the final catalyst.

[0150] 5. Calcination treatment:

[0151] Calcined at 560 °C for 3 hours to remove excess organic matter and optimize the binding of gold particles to the support.

[0152] Comparative Example 1:

[0153] Based on Example 1, the method for loading gold nanoparticles was fine-tuned, and the traditional impregnation method was used instead of atomic layer deposition. Other components remained unchanged.

[0154] Specifically as follows:

[0155] 1. Loading of gold nanoparticles:

[0156] The gold nanoparticles were loaded using the impregnation method. The gold precursor was chloroauric acid, and the gold loading amount in the impregnation method was 3%. The impregnation method did not use ALD to precisely control the dispersion of gold particles, which might lead to particle aggregation.

[0157] 2. Metal-organic framework template:

[0158] Aluminum was still used as the metal center, and the ligand was still epoxy resin.

[0159] 3. Other components:

[0160] The titanium doping ratio in ZMQ-1 molecular sieve was still 10%, the oxygen content of the nanocarbon material (graphene oxide) was still 20%, and the temperature and calcination conditions remained unchanged.

[0161] Comparative Example 2:

[0162] Based on Example 2, a comparison was made by using ZMQ-1 molecular sieve without titanium doping. The remaining components and process steps were the same as those in Example 2.

[0163] Comparative Example 3:

[0164] Based on Example 3, the particle size of the gold particles was adjusted to a larger range (10 nm), and traditional gold trichloride was used for loading without using the metal-organic framework template method. Other components were not modified.

[0165] Test Example 1:

[0166] The conversion rate and olefin product selectivity of the catalysts in each example and comparative example in the alkane dehydrogenation reaction were tested to evaluate the catalytic effect of the catalysts.

[0167] Experimental steps:

[0168] 1. Reactant preparation:

[0169] n-Hexane (C6H 14 ) was selected as the alkane substrate, and the solution concentration was configured to be 0.5 mol / L.

[0170] The hydrogen concentration was set to 5% (hydrogen-nitrogen mixed gas).

[0171] 2. Catalyst preparation:

[0172] The catalyst samples synthesized in Examples 1-5 and Comparative Examples 1-3 were taken out, and the mass of each sample was 0.2 g.

[0173] The catalysts were separately loaded into the reactor and pretreated to remove impurities and moisture.

[0174] 3. Reaction condition setting:

[0175] The reaction temperature was set at 600 °C, and the temperature was precisely controlled through the reactor.

[0176] The reaction time was 4 hours and kept constant, and the reaction was carried out using flowing hydrogen.

[0177] The reaction was carried out under atmospheric pressure, and the hydrogen flow rate was set at 10 mL / min.

[0178] 4. Reaction process:

[0179] The alkane solution and the hydrogen gas stream were fed into the reactor.

[0180] During the reaction, samples were taken every 30 minutes, and the reaction gas was analyzed using gas chromatography (GC).

[0181] 5. Data recording:

[0182] Record the alkane conversion and olefin selectivity at each sampling. After each sampling, use the GC analysis results to calculate the conversion and selectivity.

[0183] The test results are shown in Table 1:

[0184] Table 1:

[0185]

[0186] As can be seen from the data in Table 1, the catalysts of the examples of the present invention showed significant advantages, especially in terms of alkane conversion and olefin selectivity. The catalysts in Examples 1-5 were generally superior to those in Comparative Examples 1-3 in terms of conversion and selectivity, especially in the case of high olefin selectivity and low by-product formation. By loading gold nanoparticles through atomic layer deposition (ALD), the particle size of gold was strictly controlled, which effectively avoided the aggregation of gold particles and ensured the stability of the catalyst at high temperatures. The ZMQ-1 zeolite provided an appropriate pore structure, enabling alkane molecules to enter smoothly and dehydrogenation reactions to occur on the gold particles. Compared with traditional catalysts, this could improve the catalytic efficiency and selectivity.

[0187] The titanium-doped ZMQ-1 zeolite further improved the acidity and thermal stability of the catalyst. The introduction of titanium not only enhanced the adsorption ability of alkane molecules but also improved the interaction between gold particles and the support, resulting in improved dispersion and catalytic activity of gold particles during the reaction. The introduction of nitrogen-doped carbon nanotubes or graphene provided a stronger electronic interaction for gold particles, improved the electron transfer, and promoted the dehydrogenation reaction. All these factors worked together to ensure the high efficiency of the catalyst in alkane dehydrogenation reactions, especially under high-temperature and long-time reaction conditions.

[0188] For the catalyst in the comparative example, although the gold particles were loaded by the traditional impregnation method and titanium doping was not carried out, the dispersion and catalytic activity of the gold particles decreased significantly, resulting in inefficient performance of alkane conversion and olefin selectivity. Especially for the ZMQ-1 molecular sieve without titanium doping, its acidity and thermal stability were insufficient, affecting the progress of the reaction and the long-term effectiveness of the catalyst. In contrast, the catalyst of the present invention shows unique advantages in improving catalytic efficiency, stability and selectivity by optimizing the ratio of each component and the preparation method.

[0189] Test Example 2:

[0190] Test the stability of the catalysts of each example and comparative example in multiple cycle reactions, and evaluate the activity retention ability and reusability of the catalysts.

[0191] Experimental procedure:

[0192] 1. Reactant preparation:

[0193] Use n-hexane (C6H 14 ) as the alkane substrate and configure the solution concentration to be 0.5 mol / L.

[0194] Set the hydrogen concentration to 5% (hydrogen-nitrogen mixed gas).

[0195] 2. Catalyst preparation:

[0196] Take out the catalyst samples synthesized in Examples 1-5 and Comparative Examples 1-3 respectively, and weigh 0.2 g for testing.

[0197] Pretreat the catalyst to remove moisture and possible impurities.

[0198] 3. Reaction condition setting:

[0199] Set the reaction temperature to 600 °C, and the temperature is precisely controlled through the reactor.

[0200] The reaction time is 4 hours, the hydrogen concentration is 5%, and the reaction is carried out under atmospheric pressure.

[0201] 4. Cycle reaction process:

[0202] Carry out the first reaction, and record the reaction time and the alkane conversion and olefin selectivity at the end of the reaction.

[0203] After the reaction is completed, take out the catalyst for cooling and wash away the residual reactants.

[0204] Wash the post-reaction catalyst with a dry nitrogen stream to ensure the reuse of the catalyst.

[0205] The cleaned catalyst was reused for the second round of reaction, and the cyclic test was continued. Each catalyst was subjected to at least 5 rounds of reaction tests.

[0206] 5. Data recording:

[0207] After each round of reaction, the alkane conversion and olefin selectivity were determined by gas chromatography (GC).

[0208] Record the activity change of the catalyst, and calculate the alkane conversion and olefin selectivity for each round.

[0209] The test results are shown in Table 2:

[0210] Table 2:

[0211]

[0212] It can be seen from the data in Table 2 that the catalyst of the present invention exhibits excellent stability and a low decay rate in multiple cyclic tests. After the catalysts of Examples 1-5 were reused, the conversion and olefin selectivity remained at a high level. Especially in terms of maintaining the catalyst activity, the uniform distribution of gold nanoparticles played a key role. The atomic layer deposition method (ALD) precisely controlled the particle size and dispersion of gold particles, avoiding particle aggregation and sintering, which enabled the catalyst to maintain its activity for a long time under high temperature and high reaction conditions.

[0213] Titanium-doped ZMQ-1 molecular sieve also played an important role in the stability of the catalyst. The introduction of titanium element improved the acidity of the molecular sieve and enhanced the adsorption capacity of alkanes. The metal-support interaction between gold particles and the support further enhanced the stability of the catalyst, avoiding the desorption and aggregation of gold particles at high temperature. As the catalytic reaction proceeded, the interaction between gold nanoparticles and the support in the catalyst was strengthened, effectively delaying the decline of the catalyst performance.

[0214] In contrast, due to the different gold particle loading methods, the dispersibility of the comparative catalyst was poor, resulting in a rapid decline in the activity of the catalyst during repeated use. The gold particles loaded by the impregnation method were difficult to achieve a uniform distribution like that of the ALD method, and obvious particle aggregation occurred, resulting in a reduction in the active sites of the catalyst. Moreover, the undoped titanium ZMQ-1 molecular sieve had weak acidity and could not effectively support the activation of reactants. Therefore, there was a large gap in conversion and selectivity compared with the examples. Overall, the catalyst of the present invention demonstrated excellent performance during long-term use by optimizing the distribution of gold particles and the selection of the support, significantly improving the efficiency and selectivity of the alkane dehydrogenation reaction.

[0215] Although embodiments of the present invention have been shown and described, those of ordinary skill in the art will appreciate that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A gold-loaded alkane dehydrogenation catalyst, characterized in that, By weight percentage, it comprises the following components: 40% - 60% of ZMQ-1 molecular sieve, 1% - 5% of gold nanoparticles, 15% - 40% of nano-carbon material, 5% - 10% of metal-organic framework template.

2. The supported gold alkane dehydrogenation catalyst according to claim 1, wherein, The nano-carbon material is graphene or nitrogen-doped carbon nanotubes, wherein the oxygen content of graphene is 10% - 25%, and the nitrogen doping ratio of nitrogen-doped carbon nanotubes is 1% - 5%.

3. The supported gold alkane dehydrogenation catalyst according to claim 1, wherein, The average particle size of the gold nanoparticles is 2 - 5 nm, and the gold nanoparticles are uniformly loaded on the surface of the ZMQ-1 molecular sieve by atomic layer deposition.

4. The supported gold alkane dehydrogenation catalyst according to claim 1, wherein In the metal-organic framework template material, the metal center is aluminum or titanium, and its ligand is epoxy resin.

5. The supported gold alkane dehydrogenation catalyst according to claim 1, characterized in that, The ZMQ-1 molecular sieve has a 28-membered ring pore system, and the size range of the pores is 6. The supported gold alkane dehydrogenation catalyst according to claim 1, wherein 5% - 15% of titanium element is doped in the ZMQ-1 molecular sieve, and the titanium source of the titanium element is tetrabutyl titanate or isopropyl titanate.

7. A method for preparing a gold-loaded alkane dehydrogenation catalyst for preparing the gold-loaded alkane dehydrogenation catalyst according to any one of claims 1-6, characterized in that, It includes the following steps: (1) Synthesize ZMQ-1 molecular sieve, and add a titanium source during its synthesis to obtain titanium-doped ZMQ-1 molecular sieve; (2) Perform oxidation treatment and nitrogen doping treatment on graphene or carbon nanotubes to obtain functionalized nano-carbon materials; (3) Load the gold precursor by the metal-organic framework template method and obtain gold nanoparticles through thermal reduction; (4) Load the gold nanoparticles onto the titanium-doped ZMQ-1 molecular sieve, and add the functionalized nano-carbon materials into the composite catalyst by physical mixing or solvent treatment to obtain the final catalyst; (5) Calcinate the final catalyst at a temperature of 500 - 600 °C to remove residual organic substances and optimize the combination of gold particles and the carrier.

8. The preparation method of the gold-loaded alkane dehydrogenation catalyst according to claim 7, characterized in that, During the synthesis process of the ZMQ-1 molecular sieve, the silicon source used is tetraethoxysilane, the aluminum source is aluminum nitrate, the template agent is dimethyldisilane or organic amines, the crystallization temperature is controlled at 150 - 250 °C, and the crystallization time is 12 - 36 hours.

9. The preparation method of the gold-loaded alkane dehydrogenation catalyst according to claim 7, characterized in that, The gold precursor is chloroauric acid or gold trichloride, the gold deposition process is carried out by the metal-organic framework template method, and thermal reduction is carried out at a temperature of 150 - 200 °C.

10. Use of the supported gold alkane dehydrogenation catalyst according to any one of claims 1-6, characterized in that, Under the conditions of a reaction temperature of 550 - 700 °C, a hydrogen concentration of 1% - 10%, and a reaction time of 1 - 6 hours, an olefin product is obtained.

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