Device for promoting dehydrogenation of methylcyclohexane at low temperature under assistance of electric field, catalyst and preparation method of catalyst

Abstract

The invention discloses a device for promoting methylcyclohexane dehydrogenation at low temperature under the assistance of an electric field, a catalyst and a preparation method thereof, and belongs to the crossing field of catalytic chemistry, hydrogen energy technology and reaction engineering. The device is composed of a gas supply system, an electric field assisted methyl cyclohexane dehydrogenation system and a product gas analysis system which are connected through a gas pipeline. The catalyst is obtained by mechanically mixing silicon carbide powder and a platinum-loaded metal oxide modified alumina carrier, tabletting and molding, crushing and screening. The catalyst is arranged in the quartz reaction tube and is connected with the high-voltage power supply through the positive electrode and the negative electrode, and the quartz reaction tube is arranged in the high-temperature reaction furnace; by introducing an external electric field, apparent activation energy of methyl cyclohexane dehydrogenation can be remarkably reduced through a Joule heating effect and a surface electron effect, and energy consumption is greatly reduced; according to the method, hydrogen production through decomposition of methyl cyclohexane can be achieved at low temperature, operation is remarkably reduced, the operation cost is remarkably reduced, and an innovative solution is provided for achieving green hydrogen energy economy.

Description

Technical Field

[0001] This invention belongs to the interdisciplinary field of catalytic chemistry, hydrogen energy technology and reaction engineering, and specifically relates to an electric field-assisted low-temperature dehydrogenation device for methylcyclohexane, a catalyst and its preparation method. Background Technology

[0002] Economic development has driven a sustained increase in energy demand, accompanied by increasingly severe environmental problems. Hydrogen energy, due to its high energy density, the fact that its combustion product is only water and it does not produce greenhouse gases such as carbon dioxide, is considered an ideal clean energy carrier due to its environmental friendliness. The International Hydrogen Energy Council predicts that by 2050, hydrogen energy will account for 18% of global energy demand, with a market value exceeding US$2.5 trillion. The China Hydrogen Energy Alliance predicts that China's hydrogen demand will increase significantly by 2050. Therefore, hydrogen production technology has received widespread attention.

[0003] Hydrogen storage and transportation, as a crucial link between hydrogen production and use, is currently one of the key technological bottlenecks restricting the large-scale development of hydrogen energy. Achieving efficient, safe, and economical storage and transportation methods is an urgent need to promote the practical application of hydrogen energy. Organic liquid hydrogen storage technology, due to its high hydrogen storage density, safety, and convenience, is considered one of the most promising hydrogen energy storage and transportation methods. The core cycle of this technology includes two processes: hydrogenation storage of aromatics (such as toluene) and dehydrogenation of cycloalkanes (such as methylcyclohexane). The dehydrogenation reaction is a strongly endothermic process, thermodynamically requiring high temperatures (typically >400℃) to drive it, leading to problems such as high energy consumption, catalyst deactivation due to sintering and carbon deposition, and complex system thermal management. In recent years, with the rapid development of various clean energy power generation technologies such as wind power, photovoltaics, biomass, and geothermal energy, inexpensive, green, and low-carbon renewable electricity has been provided to industries and other sectors. Utilizing an external electric field to assist in driving the catalytic reaction is inexpensive and efficient, and is expected to replace traditional thermocatalytic methods, further reducing the dehydrogenation reaction temperature and achieving energy conservation and emission reduction.

[0004] Electric fields can influence catalytic processes through various pathways, such as inducing localized Joule heating within the catalyst, promoting adsorption / desorption of surface reactants or products, and lowering the activation energy of key steps, thus possessing significant potential for industrial scale-up. However, research combining an applied electric field with the low-temperature dehydrogenation reaction of methylcyclohexane has yet to be systematically reported, highlighting the important scientific and practical value of this approach. Summary of the Invention

[0005] The primary objective of this invention is to provide an electric field-assisted, low-temperature dehydrogenation device for methylcyclohexane. This device significantly reduces the required reaction temperature by applying an external electric field, achieving efficient conversion of methylcyclohexane within a lower temperature range of 200-300°C, thereby saving energy, reducing consumption, and extending catalyst life. A secondary objective of this invention is to provide a catalyst for electric field-assisted, low-temperature dehydrogenation of methylcyclohexane and its preparation method. Through steps such as composite support preparation and active component loading, a catalyst with stable structure, high metal dispersion, and suitable electrical properties is obtained.

[0006] like Figure 1 and Figure 2 As shown, the device for electric field-assisted low-temperature dehydrogenation of methylcyclohexane according to the present invention consists of a gas supply system connected by a 2-4 mm gas pipe, an electric field-assisted methylcyclohexane dehydrogenation system, and a product gas analysis system. A heating belt is wound around the gas pipe between the electric field-assisted methylcyclohexane dehydrogenation system and the product analysis system to achieve online analysis of the entire product under a heat-preserving condition (150-500℃). The gas supply system consists of a gas cylinder 1, a methylcyclohexane storage tank 2, a high-pressure constant flow pump 3, a mass flow meter 4, a one-way valve 5, a pressure gauge 6, and a gasification furnace 7. The electric field-assisted methylcyclohexane dehydrogenation system consists of an upper copper rod 8, an upper insulating connector 9, an upper foamed copper 11, a quartz reaction tube 10, a lower copper rod 8', a lower insulating connector 9', a lower foamed copper 11', a catalyst 12, a high-temperature reaction furnace 13, and a high-voltage power supply 14. The product gas analysis system consists of a timed sampler 15, a gas chromatograph 16, a cold trap 17, and a mass spectrometer 18.

[0007] The quartz reaction tube 10 is filled with catalyst 12 to form a catalyst bed. The upper and lower surfaces of the catalyst bed are respectively connected to the upper foamed copper 11 and upper copper rod 8 as positive electrodes, and the lower foamed copper 11' and lower copper rod 8' as negative electrodes. The upper insulating joint 9 and lower insulating joint 9' are three-way joints made of polyetheretherketone (PEEK) material. The upper insulating joint 9 and lower insulating joint 9' are sealed and installed at the upper and lower ends of the quartz reaction tube 10. The upper copper rod 8 and lower copper rod 8' are inserted from the middle joints of the upper insulating joint 9 and lower insulating joint 9', respectively. The side joint of the upper insulating joint 9 is used to introduce methylcyclohexane and carrier gas, and the side joint of the lower insulating joint 9' is used to discharge unconverted methylcyclohexane and the product toluene and hydrogen. The upper copper rod 8 and lower copper rod 8' are respectively connected to the positive and negative terminals of the high-voltage power supply 14, thereby forming a uniform and stable electric field on the catalyst bed.

[0008] Methylcyclohexane is stored in storage tank 2 and precisely delivered to gasifier 7 via high-pressure constant flow pump 3. Simultaneously, carrier gas (nitrogen or argon) is supplied from gas cylinder 1, with its flow rate controlled by mass flow meter 4, and enters gasifier 7 after passing through one-way valve 5. Methylcyclohexane is completely vaporized in gasifier 7 and uniformly mixed with the carrier gas to form a gaseous reactant. This gaseous reactant is then carried by the carrier gas through upper insulating connector 9 to the upper end of quartz reaction tube 10. Quartz reaction tube 10 is placed inside high-temperature reactor 13, where a thermal field is created to provide and maintain heat. The required temperature for the reaction; under the combined action of an electric field and a thermal field, methylcyclohexane undergoes a highly efficient dehydrogenation reaction on the surface of catalyst 12, producing toluene and hydrogen; unconverted methylcyclohexane and the products toluene and hydrogen exit the lower end of the quartz reaction tube 10 through the side connector of the lower insulating connector 9'; the unconverted methylcyclohexane and the products toluene and hydrogen are periodically introduced into the gas chromatograph 16 for quantitative analysis of components by the timed sampler 15 (the gas chromatograph can quantitatively analyze the components of the products, and then calculate the conversion rate of methylcyclohexane dehydrogenation).

[0009] During the injection phase of the gas chromatograph 16, unconverted methylcyclohexane and its product toluene, along with hydrogen, enter the chromatographic analysis and then enter the cold trap. During the non-injection phase of the gas chromatograph 16, unconverted methylcyclohexane and its product toluene, along with hydrogen, directly enter the cold trap. The cold trap liquefies and collects the unconverted methylcyclohexane and toluene, while the hydrogen and carrier gas are directly released into the atmosphere.

[0010] Furthermore, the unconverted methylcyclohexane and the product toluene, along with hydrogen, are controlled by the timed sampler 15 to enter the mass spectrometer 18 for further confirmation of the product structure.

[0011] The high-pressure constant flow pump 3 has a flow control range of 0.02~10mL / min, which can achieve precise and stable control of the methylcyclohexane feed rate.

[0012] The high-temperature reactor 13 (such as Hunan Huasi HF-500, Beijing Haifuda Technology HL19-1100, etc.) adopts an integrated fiber sintering furnace chamber, which has the advantages of high temperature resistance, good heating stability and temperature uniformity. The temperature control range is from room temperature to 800℃, which can meet the thermal field requirements of dehydrogenation reaction under different temperature conditions. It has a special structure, with M-type heaters placed in the hollow areas at the upper and lower ends of the reactor to heat the hollow areas, ensuring that there are no cold spots in the pipes after the vaporization tube and the joints at the upper and lower ends of the reaction tube, and facilitating the disassembly of the reaction tube joints without the need to wrap heating tape.

[0013] The high-voltage power supply 14 has an adjustable output voltage of 0~2000V and supports constant current or constant voltage modes, enabling the regulation of the catalytic process by different electric field strengths and waveforms. By applying voltage to the positive and negative electrodes, the high-voltage power supply 14 applies an axial electric field to the solid catalyst material inside the quartz reaction tube 10, achieving a synergistic reaction process under the electric field.

[0014] The gas chromatograph 16 is provided by FUL, and the F60 gas chromatograph main unit has a built-in RB-INNOWAX capillary column for precise separation of organic matter.

[0015] The preparation method of the catalyst 12 includes physical mixing and granulation steps, specifically: silicon carbide powder and platinum-loaded metal oxide modified alumina carrier are mechanically mixed thoroughly at a predetermined mass ratio (the mass ratio of silicon carbide to platinum-loaded metal oxide modified alumina carrier is 2~4:1) until uniformly distributed; then the uniformly mixed powder is compressed into tablets by a tablet press, and the tablets are moderately pulverized and sieved to obtain catalyst particles with a certain particle size range (40~80 mesh), good mechanical strength and regular shape; the catalyst particles can be directly packed into the quartz reaction tube 10 for electric field-assisted methylcyclohexane dehydrogenation reaction.

[0016] The introduction of silicon carbide mainly plays the following roles: (1) as a conductive component, it forms a conductive network inside the support, enabling the catalyst to form an effective potential distribution in the electric field and generate Joule heating or electronic effects; (2) its high thermal conductivity helps to distribute the heat of the reaction system evenly and avoid local overheating; (3) its chemical inertness can enhance the stability of the catalyst in the reaction environment.

[0017] The preparation method of the platinum-loaded metal oxide modified alumina support of the present invention comprises the following steps:

[0018] (1) Preparation of modified carrier:

[0019] Alumina powder was dispersed in deionized water and stirred at 400-600 r / min to form a uniform suspension. Magnesium nitrate, zinc nitrate, molybdenum nitrate, cerium nitrate, lanthanum nitrate, samarium nitrate, or praseodymium nitrate were slowly added to the suspension at a mass ratio of 1:5-20 to alumina. The mixture was stirred for 30-60 min to ensure that the magnesium nitrate, zinc nitrate, molybdenum nitrate, cerium nitrate, lanthanum nitrate, samarium nitrate, or praseodymium nitrate were in full contact with the alumina. Then, ammonia solution was added dropwise while stirring to adjust the pH of the system to 9-10. The mixture was stirred and adsorbed for 1.5-3.0 h. The resulting mixture was then centrifuged. The solid precipitate was washed with deionized water until neutral and dried at 100-120 °C for 6-10 h. The dried solid was placed in a muffle furnace and calcined at a heating rate of 3-6 °C / min from room temperature to 550-650 °C for 10-15 h. The furnace was then allowed to cool naturally to room temperature to obtain a metal oxide-modified alumina support.

[0020] (2) Loading of active components:

[0021] Weigh 0.5 g of metal oxide-modified alumina support, add a certain amount of 10 mg / mL chloroplatinic acid aqueous solution to make the platinum mass loading in the catalyst 0.1-5%, then add 50-100 mL of methanol-water mixed solution (where the volume ratio of methanol to water is 1:2-5), stir at room temperature for 10-20 min to fully impregnate and disperse the support; then degas the reaction system under vacuum for 2-5 min to remove dissolved oxygen and bubbles in the system; under continuous stirring, irradiate the reaction system with a 200-400 W xenon lamp source to carry out photochemical deposition reaction for 20-60 min; after the reaction, filter the mixture to separate, wash the obtained solid with deionized water and anhydrous ethanol 3-5 times in sequence, and vacuum dry at 60-80℃ for 6-12 h to obtain platinum-loaded metal oxide-modified alumina support.

[0022] The present invention has the following beneficial effects:

[0023] (1) Low temperature and high efficiency: The introduction of an external electric field can significantly reduce the apparent activation energy of methylcyclohexane dehydrogenation through the Joule heating effect and surface electronic effect (such as reducing the CH bond dissociation energy), so that the reaction can be carried out efficiently at a temperature more than 50°C lower than that of traditional thermal catalysis, and the energy consumption is greatly reduced.

[0024] (2) Suppressing carbon deposition: Low temperature reaction conditions are inherently conducive to suppressing carbon deposition precursor reactions such as deep dehydrogenation and polymerization. The electric field may promote the overflow and desorption of adsorbed hydrogen, further reducing carbon deposition and extending catalyst life.

[0025] (3) Strong process integration: The electric field auxiliary device is easy to integrate with existing fixed bed or fluidized bed reactors, and is flexible in operation, providing a feasible path for energy-saving transformation of existing dehydrogenation units or development of new processes.

[0026] In summary, this invention provides a novel technical approach for hydrogen production from methylcyclohexane via an electric field. Compared to traditional methods, this invention enables hydrogen production from methylcyclohexane at low temperatures, significantly reducing operating costs and providing an innovative solution for achieving a green hydrogen economy. Attached Figure Description

[0027] To more clearly illustrate the specific embodiments of the present invention, the accompanying drawings used in the specific embodiments will be briefly described below. Obviously, the drawings in the following description only illustrate some embodiments of the present invention.

[0028] Figure 1 A schematic diagram of the overall structure of an electric field-assisted methylcyclohexane decomposition hydrogen production system;

[0029] Figure 2 Detailed structural diagram of an electric field-assisted methylcyclohexane dehydrogenation system;

[0030] Figure 3 The graph shows the conversion rate of methylcyclohexane dehydrogenation catalyzed by Example 1 under electric field assistance and without electric field assistance as a function of temperature. The graph shows that in the lower temperature range, the electric field can work in conjunction with the thermal field to promote the methylcyclohexane dehydrogenation reaction, and this promoting effect becomes more significant as the temperature decreases.

[0031] Figure 1 and Figure 2 The components are named as follows: Gas cylinder 1, Methylcyclohexane storage tank 2, High-pressure constant flow pump 3, Mass flow meter 4, One-way valve 5, Pressure gauge 6, Gasification furnace 7, Upper copper rod 8, Upper insulating connector 9, Upper foamed copper 11, Quartz reaction tube 10, Lower copper rod 8', Lower insulating connector 9', Lower foamed copper 11', Catalyst 12, High-temperature reaction furnace 13, High-voltage power supply 14, Timed sampler 15, Gas chromatograph 16, Cold trap 17, Mass spectrometer 18. Detailed Implementation

[0032] Inside the quartz reaction tube 10, an electrode pair is arranged axially, consisting of a positive electrode composed of an upper copper rod 8 and an upper copper foam 11, and a negative electrode composed of a lower copper foam 11' and a lower copper rod 8'. The catalyst 12 is uniformly packed between the two electrodes, forming a structurally stable catalyst-electric field composite bed. The copper rod electrode is connected to an external high-voltage power supply 14 via a dedicated conductive clamp inside the high-temperature reactor 13. This configuration ensures that the electric field lines uniformly penetrate the entire catalyst bed, achieving full coupling between the catalyst particles and the electric field.

[0033] At the start of the reaction, the high-temperature reactor 13 is first turned on to heat the catalyst bed to the set reaction temperature (preferably 200~320℃). After the temperature stabilizes, the high-voltage power supply 14 is turned on, and the output current is controlled at 0.001A to gradually apply an electric field of a preset strength (preferably 600~2000V) between the positive and negative electrodes. Under the synergistic effect of the electric and thermal fields, a mixture of methylcyclohexane and carrier gas supplied by the gasification furnace 7 is introduced. The electric field significantly improves the reaction rate under low-temperature conditions by promoting proton migration on the catalyst surface and lowering the CH bond dissociation energy barrier. After the reaction, the gaseous products are qualitatively and quantitatively analyzed by gas chromatograph 16 and mass spectrometer 18 to identify unconverted methylcyclohexane and the generated toluene.

[0034] Example 1

[0035] Commercial alumina powder was dispersed in deionized water and stirred at 400 rpm to form a homogeneous suspension. Lanthanum nitrate solution was slowly added, maintaining a lanthanum nitrate to alumina mass ratio of 1:10. After stirring for 60 min, ammonia solution was added dropwise to adjust the pH to 9.5, and adsorption was continued under this condition for 2 h. The resulting mixture was centrifuged, and the precipitate was washed with deionized water until neutral and dried at 100 °C for 8 h. The dried solid was then placed in a muffle furnace and calcined at 600 °C at a rate of 5 °C / min for 12 h. After natural cooling, lanthanum oxide-modified alumina support was obtained. 0.5 g of the modified support was weighed and placed in a photoreactor, along with 1.1 mL of a 10 mg / mL chloroplatinic acid aqueous solution and 60 mL of a methanol-water mixture (methanol to water volume ratio of 1:5). The mixture was stirred at room temperature for 15 min to ensure uniform impregnation of the support. The system was evacuated for 2 min to remove air bubbles, and then photodeposited under continuous stirring with a 300 W xenon lamp for 30 min. After the reaction was completed, the mixture was filtered, and the resulting solid was washed four times with deionized water and anhydrous ethanol, and then dried under vacuum at 70°C for 9 hours to obtain the platinum-loaded lanthanum oxide-modified alumina catalyst (platinum loading 3%, product mass 0.6 g).

[0036] 0.1g of the above catalyst was mixed with 0.2g of silicon carbide, pulverized, sieved, and then packed into a quartz reaction tube 10 with an outer diameter of 10mm and an inner diameter of 6mm. The gasification furnace temperature was set to 150℃ to ensure complete vaporization of methylcyclohexane; the temperature of the high-temperature reactor 13 was set to 150~380℃. A DC power supply was connected, and the output current was controlled to be 0.001A, with the output voltage adaptive. The methylcyclohexane feed flow rate was set to 0.02mL / min, and the carrier gas (such as nitrogen) flow rate was 30mL / min. The gaseous products after the reaction were analyzed using a gas chromatograph 16 equipped with a flame ionization detector (FID) and a thermal conductivity detector (TCD) to accurately quantify the contents of methylcyclohexane, toluene, and hydrogen, thereby calculating the conversion rate. When the reactor temperature is 250°C, using the catalyst of this embodiment, the thermal catalytic conversion rate of methylcyclohexane can reach 34.6%, and the toluene selectivity is 98.4%; under the assistance of a 600V electric field, the conversion rate of methylcyclohexane can reach 64.0%, and the toluene selectivity is 99.8%, and the performance can remain stable for 50 hours of continuous operation.

[0037] Example 2

[0038] The catalyst preparation method is the same as in Example 1, except that lanthanum nitrate is replaced with cerium nitrate. When using the catalyst in this example at a reactor temperature of 250°C, the thermal catalytic conversion rate of methylcyclohexane reaches 34.2%, and the toluene selectivity is 97.3%. Under a 600V electric field, the conversion rate of methylcyclohexane reaches 53.7%, and the toluene selectivity is 98.9%, and the performance remains stable for 24 hours of continuous operation.

[0039] Example 3

[0040] The catalyst preparation method is the same as in Example 1, except that lanthanum nitrate is replaced with magnesium nitrate. When the reactor temperature is 250°C, using the catalyst of this example, the thermal catalytic conversion rate of methylcyclohexane can reach 22.6%, and the toluene selectivity is 98.8%; under a 600V electric field, the conversion rate of methylcyclohexane can reach 41.3%, and the toluene selectivity is 99.3%, and the performance remains stable for 10 hours of continuous operation.

Claims

1. An apparatus for promoting the dehydrogenation of methylcyclohexane with electric field assistance at low temperature, characterized in that: It consists of a gas supply system connected by a gas pipeline, an electric field-assisted methylcyclohexane dehydrogenation system, and a product gas analysis system. The gas pipeline between the electric field-assisted methylcyclohexane dehydrogenation system and the product analysis system is wrapped with a heating belt to realize online analysis of the entire product under heat preservation conditions. The gas supply system consists of a gas cylinder (1), a methylcyclohexane storage tank (2), a high-pressure constant flow pump (3), a mass flow meter (4), a one-way valve (5), a pressure gauge (6), and a gasification furnace (7). The electric field-assisted methylcyclohexane dehydrogenation system consists of an upper copper rod (8), an upper insulating connector (9), an upper foamed copper (11), a quartz reaction tube (10), a lower copper rod (8'), a lower insulating connector (9'), a lower foamed copper (11'), a catalyst (12), a high-temperature reaction furnace (13), and a high-voltage power supply (14). The product gas analysis system consists of a timed sampler (15), a gas chromatograph (16), and a cold trap (17). The mass spectrometer (18) consists of a catalyst (12) packed inside a quartz reaction tube (10) to form a catalyst bed. The upper and lower surfaces of the catalyst bed are connected to the upper foamed copper (11) and upper copper rod (8) as positive electrodes, and the lower foamed copper (11') and lower copper rod (8') as negative electrodes, respectively. The upper insulating connector (9) and lower insulating connector (9') are three-way connectors. The upper insulating connector (9) and lower insulating connector (9') are sealed and installed at the upper and lower ends of the quartz reaction tube (10). The upper copper rod (8) and lower copper rod (8') are inserted from the middle connectors of the upper insulating connector (9) and lower insulating connector (9'), respectively. The side connector of the upper insulating connector (9) is used to introduce methylcyclohexane and carrier gas, and the side connector of the lower insulating connector (9') is used to discharge unconverted methylcyclohexane and the product toluene and hydrogen. The upper copper rod (8) and lower copper rod (8') are connected to the positive and negative electrodes of the high-voltage power supply (14), respectively.

2. The device for promoting the dehydrogenation of methylcyclohexane with electric field assistance at low temperature as described in claim 1, characterized in that: Methylcyclohexane is stored in a storage tank (2) and precisely delivered to the gasifier (7) by a high-pressure constant flow pump (3); simultaneously, the carrier gas is supplied by a gas cylinder (1), the flow rate is controlled by a mass flow meter (4), and enters the gasifier (7) after passing through a one-way valve (5); methylcyclohexane is completely vaporized in the gasifier (7) and uniformly mixed with the carrier gas to form a gaseous reaction material, which is then carried by the carrier gas through the upper insulating joint (9) into the upper end of the quartz reaction tube (10); the quartz reaction tube (10) is placed in a high-temperature reaction furnace (13), and a thermal field is formed in the high-temperature reaction furnace (13) to provide and maintain the temperature required for the reaction; under the combined action of the electric field and the thermal field, methylcyclohexane reacts with the catalyst (1) 2) A highly efficient dehydrogenation reaction occurs on the surface, generating toluene and hydrogen. Unconverted methylcyclohexane and the product toluene and hydrogen leave the lower end of the quartz reaction tube (10) through the side connector of the lower insulating connector (9'), and are periodically entered into the gas chromatograph (16) for component quantitative analysis under the control of the timed sampler (15). During the sample injection of the gas chromatograph (16), unconverted methylcyclohexane and the product toluene and hydrogen enter the cold trap after chromatographic analysis. During the non-sample injection period of the gas chromatograph (16), unconverted methylcyclohexane and the product toluene and hydrogen are directly placed in the cold trap. The cold trap liquefies and collects the unconverted methylcyclohexane and toluene, while hydrogen and carrier gas are directly discharged into the atmosphere.

3. The device for promoting the dehydrogenation of methylcyclohexane with electric field assistance at low temperature as described in claim 1, characterized in that: Unconverted methylcyclohexane and the product toluene, along with hydrogen, exit the lower end of the quartz reaction tube (10) through the side connector of the lower insulating connector (9'), and are then controlled by the timed sampler (15) to enter the mass spectrometer (18) to confirm the structure of the products.

4. A catalyst for promoting the dehydrogenation of methylcyclohexane under electric field-assisted low temperature conditions, characterized in that: Silicon carbide powder and platinum-loaded metal oxide modified alumina carrier are mechanically mixed thoroughly at a mass ratio of 2-4:1 until they are evenly distributed. The uniformly mixed powder is then compressed into tablets using a tablet press, and the tablets are pulverized and sieved to obtain catalyst particles with a certain particle size range, good mechanical strength, and regular shape.

5. The catalyst for promoting the dehydrogenation of methylcyclohexane under electric field-assisted low temperature as described in claim 4, characterized in that: The preparation steps of the platinum-loaded metal oxide modified alumina support are as follows: (1) Preparation of modified carrier: Alumina powder is dispersed in deionized water and stirred at 400-600 r / min to form a uniform suspension. Metal nitrate with a mass ratio of 1:5-20 to alumina is slowly added to the suspension, and stirring is continued for 30-60 min to ensure that the metal nitrate and alumina are in full contact. Subsequently, ammonia solution was added dropwise under stirring to adjust the pH of the system to 9-10, and the adsorption was continued for 1.5-3.0 h. The resulting mixture was then centrifuged, and the solid precipitate was washed with deionized water until neutral and dried at 100-120℃ for 6-10 h. The dried solid was placed in a muffle furnace and calcined at a heating rate of 3-6℃ / min from room temperature to 550-650℃ for 10-15 h. The furnace was then allowed to cool naturally to room temperature to obtain a metal oxide modified alumina support. (2) Loading of active components: Weigh 0.5 g of metal oxide-modified alumina support, add a certain amount of 10 mg / mL chloroplatinic acid aqueous solution to make the platinum mass loading in the catalyst 0.1-5%, then add 50-100 mL of methanol-water mixed solution, and stir at room temperature for 10-20 min to fully impregnate and disperse the support; then degas the reaction system under vacuum for 2-5 min to remove dissolved oxygen and bubbles in the system; under continuous stirring, irradiate the reaction system with a 200-400 W xenon lamp source to carry out photochemical deposition reaction for 20-60 min; after the reaction, filter the mixture to separate it, wash the obtained solid with deionized water and anhydrous ethanol 3-5 times in sequence, and dry it under vacuum at 60-80℃ for 6-12 h to obtain platinum-loaded metal oxide-modified alumina support.

6. The catalyst for promoting the dehydrogenation of methylcyclohexane under electric field-assisted low temperature as described in claim 5, characterized in that: The metal nitrate is at least one of magnesium nitrate, zinc nitrate, molybdenum nitrate, cerium nitrate, lanthanum nitrate, samarium nitrate, and praseodymium nitrate.

7. The catalyst for promoting the dehydrogenation of methylcyclohexane under electric field-assisted low temperature as described in claim 5, characterized in that: In a methanol-water mixed solution, the volume ratio of methanol to water is 1:2~5.

8. A catalyst for promoting the dehydrogenation of methylcyclohexane under electric field assistance at low temperature as described in any one of claims 4 to 7, characterized in that: Applied to the device for promoting the dehydrogenation of methylcyclohexane with electric field assistance at low temperature as described in any one of claims 1 to 3.

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