Process and apparatus for preparing reduced function alumina supports and catalysts using carbon-containing gas mixtures

Abstract

This invention provides a method and apparatus for preparing alumina support and catalyst with reducing function using a carbon-containing mixed gas. The preparation steps of the alumina support and catalyst with reducing function are as follows: (1) The alumina precursor is placed in a reactor and reacted with the alumina precursor by contacting it with a carbon-containing mixed gas at 400-600℃. The gas flow rate and reaction time are controlled to obtain an alumina support with reducing function. (2) Metal is loaded by impregnation. The metal is reduced in situ during the loading process to obtain a noble metal catalyst. An apparatus for preparing alumina support with reducing function using a carbon-containing mixed gas is also provided. The prepared alumina support with reducing function can precisely control the in-situ reduction of the noble metal on the support during the impregnation and loading of the noble metal, avoiding the traditional unit operation process of high energy consumption and dangerous first loading followed by hydrogenation reduction.

Description

Technical Field

[0001] This invention relates to the field of catalyst preparation, specifically to the preparation of an alumina support with reducing function and a simple technique for preparing a noble metal catalyst. Background Technology

[0002] Catalysts are the "heart" and foundation of catalytic reactions. Compared to non-precious metal catalysts, precious metal catalysts are highly valued for their excellent activity, selectivity, and stability. They are widely used in reactions such as hydrogenation, dehydrogenation, oxidation, reduction, isomerization, aromatization, cracking, and synthesis, playing a very important role in chemical, petroleum refining, petrochemical, pharmaceutical, environmental protection, and new energy fields.

[0003] Noble metal catalysts typically consist of a noble metal active component, an additive, and a support. Common methods for loading noble metals include sol-gel fixation and impregnation. However, both methods have some drawbacks. Sol-gel fixation is complex, involving many steps and chemical reactions, requiring strict control of temperature, pH, and reaction time. During sol-gel fixation, metal particles often require organic macromolecules as protective agents. Due to the lack of strong interaction between the metal and the support, the active component is easily lost during the reaction, and the residual protective agent will affect the stability and purity of the catalyst. Impregnation is simple, efficient, and convenient, but during impregnation, the solvation effect and the clustering effect of the active component make it difficult to achieve high dispersion of the active component, resulting in a large amount of active component and low metal utilization. Furthermore, high-temperature reduction of the metal is required after impregnation, which leads to the aggregation of the loaded metal. The reduction process usually uses hydrogenation, which is inherently dangerous. For example, in patent CN 109261145 A, after obtaining the activated carbon catalyst loaded with noble metal, it still needs to be reduced at 160°C in a hydrogen atmosphere for 10 hours. For example, in patent CN 104399537 A, the Pd / Al2O3 catalyst was obtained, but it still needs to be reduced at 200°C in a hydrogen atmosphere for 3 to 50 hours.

[0004] Currently, finding a simple, safe, and energy-efficient technology to prepare excellent noble metal catalysts remains a research direction in catalysts. Therefore, preparing noble metal catalysts without the addition of external reducing agents is of great significance, as it can avoid dangerous hydrogenation reduction processes, reduce the agglomeration of supported metals, and improve the quality of the catalyst. Summary of the Invention

[0005] The purpose of this invention is to provide a method and apparatus for preparing alumina support and catalyst with reducing function by treating alumina precursor with a carbon-containing mixed gas.

[0006] The present invention provides a method for preparing alumina support and catalyst with reducing function using a carbon-containing mixed gas. The method involves reacting a carbon-containing mixed gas with an alumina precursor. The carbon-containing mixed gas adsorbs onto the surface of the alumina precursor, inducing a change in the Al-O bond structure in the alumina support. Activated hydroxyl groups dissociate on the surface, forming active intermediates H*. Part of these active intermediates are removed, while the remaining portion migrates on the surface and eventually re-stabilizes, forming an alumina support with a reducing Al-OH* bond structure. This alumina support is then loaded with a noble metal salt solution using an impregnation method. During the loading process, the Al-OH* structure on the support surface can reduce the noble metal on the support in situ, effectively maintaining the small size and high dispersion of the metal particles, achieving simultaneous loading and reduction.

[0007] The method for preparing alumina support and catalyst with reducing function using a carbon-containing mixed gas comprises the following steps:

[0008] A: The alumina precursor is placed in a reactor and sealed. First, the protective gas is introduced into the reactor through a deoxygenation device. Then, the M gas is deoxygenated through the deoxygenation device and introduced into the reactor. The flow rates of the M gas and the protective gas are controlled by a mass flow meter to adjust the ratio of the reactants. After the reactants are introduced for 8-15 minutes, the reactor is heated by programmed temperature rise at a rate of 2-15℃ / min. The reaction temperature is 400-600℃, and the reaction time is 1-10 hours, preferably 2-6 hours. The flow rate of the reactants is 10mL / min-100mL / min, preferably 10mL / min-60mL / min. After the reaction is completed, the mixture is cooled to room temperature. The sample is then quickly removed, vacuum-packed, and ready for use to obtain a reducing alumina support with a γ-type crystal structure.

[0009] The reaction gas consists of a carbon-containing gas M and a protective gas, wherein the volume content of M is 5%-60% and the remainder is a protective gas, and preferably the volume content of M is 10%-40%.

[0010] The protective gas is an inert gas, such as nitrogen or argon.

[0011] The deoxygenation device is a drying tube with added 401 manganese-based deoxidizer.

[0012] M is one or more of CH4, C2H2, CO, C2H4, and C2H6. Preferably, it is any 1 to 3 of CH4, C2H2, CO, C2H4, and C2H6.

[0013] The alumina precursor is one of spherical boehmite, bar-shaped boehmite, powdered boehmite, or powdered aluminum hydroxide; preferably, it is powdered aluminum hydroxide or powdered boehmite.

[0014] During the above reaction, carbon-containing gas molecules in the carbon-containing mixed gas adsorb onto the surface of the alumina precursor, inducing a change in its Al-O bond structure and activating its surface hydroxyl groups to generate active intermediates H*. Some of the active H* is removed, while the other part of the active intermediate migrates on the surface and re-stabilizes on the surface, forming a reducing Al-OH* bond structure.

[0015] B: Add an equal volume of precious metal impregnation solution to the alumina carrier from step A, wherein the concentration of the precious metal solution is determined according to the content of precious metal required for the final product.

[0016] For the formed alumina carrier, the mixture of the formed alumina carrier and the noble metal solution is mixed evenly and placed in an oven to dry at a temperature of 20-90℃ for 6-36 hours to obtain an alumina carrier loaded with noble metal elements.

[0017] For powdered alumina carriers, a mixture of powdered alumina carriers and noble metal solutions is placed in a water bath, and magnetic stirrers are added for stirring at a speed of 100-1000 rpm. When the solution is almost dry, it is placed in an oven to dry, thereby obtaining alumina carriers loaded with noble metal elements.

[0018] During the impregnation process, the metal cations gradually approach the surface of the support. Due to charge interaction, they migrate to the vicinity of the Al-OH* bond. The Al-OH* structure donates electrons to the metal cations, thereby reducing them to form metal atoms. Finally, the reduced noble metal catalyst is obtained, achieving simultaneous loading and reduction.

[0019] The aforementioned apparatus for preparing alumina carriers with reducing function using a carbon-containing mixed gas comprises an M gas storage tank, a protective gas storage tank, a deoxygenation device, a reactor, and a tail gas collection bottle. The M gas storage tank and the protective gas storage tank are connected to the deoxygenation device via mass flow meters. The deoxygenation device is connected to the reactor via a gas path. Pressure gauges are installed at the reactor's inlet and outlet. A waste gas collection container is connected to the bottom of the reactor. There are n M gas storage tanks, where n is determined by the number of types of M gas selected, and n = 1-5.

[0020] The prepared catalyst was characterized, and the results are as follows:

[0021] Depend on Figure 2 The XRD pattern shows that the γ-alumina support was successfully prepared by this method.

[0022] Depend on Figure 3 The XRD pattern did not show obvious Pd particle peaks, indicating that Pd is relatively uniformly dispersed.

[0023] Depend on Figure 4 , 5The XPS spectra of 6 show that Ru, Pd, and Au have been reduced.

[0024] Depend on Figure 7 The HRTEM indicates that Pd is well dispersed and relatively uniform.

[0025] Depend on Figure 8 The performance comparison shows that the Pd / Al2O3 catalyst prepared by this method has a certain improvement on the acetylene semi-hydrogenation performance.

[0026] Beneficial effects:

[0027] The key feature of this invention is the use of a carbon-containing mixed gas to specially treat the surface of an alumina precursor during its preparation, resulting in an alumina support with unique reducing properties. The alumina prepared by this method can directly reduce noble metals during impregnation without the addition of any reducing agent. This avoids the traditional process of hydrogen reduction after loading, prevents the agglomeration of noble metals caused by high-temperature reduction, and ensures good dispersion of the noble metals on the surface. It also avoids the high energy consumption and the dangers of hydrogen reduction in high-temperature reduction processes.

[0028] The provided apparatus for preparing alumina carriers with reducing function can control the proportion of reaction gas by adjusting the flow meter ratio. The gas enters the reactor through the gas path and comes into full contact with the sample. The reaction gas is finally collected by the gas collection device and can be reused.

[0029] The catalytic performance of the catalyst prepared in this invention for the acetylene half-hydrogenation reaction was tested. Compared with the catalyst reduced by conventional methods, the catalyst prepared in this invention has a certain improvement in catalytic performance. Attached image description:

[0030] Figure 1 This is an apparatus for preparing an alumina carrier with reducing function. 1 is an M gas storage tank (1-1 to 1-n represent the number of tanks), 2 is a protective gas storage tank, 3 is an inlet valve, 4 is a mass flow meter, 5 is a deoxygenation device, 6 is a pressure gauge, 7 is a reactor, 8 is a gas sampling port, 9 is an outlet valve, and 10 is a tail gas collection bottle.

[0031] Figure 2 The images show the XRD patterns of the alumina supports prepared in Examples 3 and 4.

[0032] Figure 3 The images show the XRD patterns of Pd-loaded alumina in Examples 8 and 9.

[0033] Figure 4 The image shows the Pd3d XPS spectrum of Pd-loaded alumina in Example 1.

[0034] Figure 5 The image shows the Ru3p XPS spectrum of Ru-loaded alumina in Example 3.

[0035] Figure 6 The image shows the Au4f XPS spectrum of Au-loaded alumina in Example 4.

[0036] Figure 7 The image shows an HRTEM image of Pd-loaded alumina from Example 7.

[0037] Figure 8 The catalytic performance of acetylene semi-hydrogenation is compared between the Pd / Al2O3 catalyst prepared in Example 8 and the Pd / Al2O3 catalyst prepared by conventional hydrogenation reduction. Detailed Implementation

[0038] In the following examples, the gas percentage is the volume percentage.

[0039] Example 1

[0040] A. Weigh 10g of powdered boehmite sample and place it in the reactor, seal it, and first introduce the protective gas into the reactor through a deoxygenation device to check the airtightness of the device. M gas is selected from methane, ethane, and carbon monoxide, which are introduced into the reactor after passing through the deoxygenation device. The flow rate ratio of methane, ethane, carbon monoxide, and protective gas is controlled at 3:7:3:7 using a mass flow meter, so that the gas ratio flowing through the reactor is 15% CH4 / 35% C2H6 / 15% CO / 35% N2 (protective gas). Programmable heating is used, with the temperature increased to 450℃ at a rate of 5℃ / min, and the gas flow rate adjusted to 35mL / min. The reaction time is 4h. After the reaction, cool to room temperature, quickly remove the sample, and obtain a reducing alumina support, which is then vacuum-packed for later use. The deoxygenation device uses a 401 manganese-based deoxidizer for deoxygenation.

[0041] B. Place the alumina support from step A into a 100mL beaker, add an equal volume of 0.1% sodium chloropalladium solution, place it in a 40℃ water bath, and rotate the magnetic spinner at 550r / min. After the water in the beaker has almost dried, place the sample in a 70℃ oven to dry, and obtain Pd-loaded alumina.

[0042] Example 2

[0043] A. Weigh 5g of spherical boehmite sample and place it in the reactor, seal it, and first introduce the protective gas into the reactor through a deoxygenation device to check the airtightness of the device. The M gas is selected as acetylene and methane, which are introduced into the reactor after passing through the deoxygenation device. The flow rate ratio of acetylene, methane, and protective gas is controlled at 3:2:5 using a mass flow meter, so that the gas ratio flowing through the reactor is 30% C2H2 / 20% CH4 / 50% N2 (protective gas). Programmable heating is used, with a heating rate of 10℃ / min to 550℃, and the gas flow rate adjusted to 35mL / min. The reaction time is 3h. After the reaction is complete, cool to room temperature, quickly remove the sample, and obtain a reducing alumina support, which is then vacuum-packed for later use. The deoxygenation device uses a 401 manganese-based deoxidizer for deoxygenation.

[0044] B. Place the sample from step A into a 50 mL sample tube, add an equal volume of 4% chloroauric acid solution, sonicate for 5 minutes, and then immerse the sample in an 80 °C oven for 16 h to obtain Au-loaded alumina.

[0045] Example 3

[0046] A. Weigh 10g of powdered boehmite sample and place it in the reactor. Seal the reactor. First, introduce the protective gas into the reactor through a deoxygenation device and check the airtightness of the device. Methane and acetylene are selected as the M gas. After passing through the deoxygenation device, the M gas enters the reactor. The flow rate ratio of methane, acetylene, and protective gas is controlled at 7:4:9 using a mass flow meter, ensuring a gas ratio of 35% CH4 / 20% C2H2 / 45% N2 (protective gas) flowing through the reactor. A programmed temperature rise method is used, increasing the temperature to 450℃ at a rate of 10℃ / min. The gas flow rate is adjusted to 35mL / min, and the reaction time is 3 hours. After the reaction, cool to room temperature and quickly remove the sample to obtain a reducing alumina support, which is then vacuum-packed for later use. The deoxygenation device utilizes a 401 manganese-based deoxidizer for deoxygenation.

[0047] B. Place the sample from step A into a 100mL beaker, add an equal volume of 5% ruthenium chloride solution, place it in a 40℃ water bath, rotate the magnetic spindle at 500r / min, and after the water in the beaker has almost dried, place the sample in an 80℃ oven to dry, thus obtaining Ru-loaded alumina.

[0048] Example 4

[0049] A. Weigh 4g of powdered boehmite sample and place it in a reactor. Seal the reactor. First, introduce the protective gas into the reactor through a deoxygenation device and check the airtightness of the apparatus. Methane and carbon monoxide are selected as the protective gas (M). After passing through the deoxygenation device, the Methane, carbon monoxide, and protective gas flow rates are controlled at a ratio of 11:1:8 using a mass flow meter, ensuring a gas ratio of 55% CH4 / 5% CO / 40% N2 (protective gas) flowing through the reactor. A programmed temperature rise method is used, increasing the temperature to 250℃ at a rate of 10℃ / min, adjusting the gas flow rate to 35mL / min, and the reaction time to 3h. Then, the reaction gas concentration is changed to 20% CH4 / 80% N2 (protective gas); the gas flow rate is 50mL / min; and the temperature is increased to 550℃ at a rate of 10℃ / min, with a reaction time of 2h. After the reaction, cool to room temperature, quickly remove the sample, and obtain a reducing alumina support, which is then vacuum-packed for later use. The deoxygenation device uses 401 manganese-based deoxidizer for deoxygenation.

[0050] B. Place the sample from step A into a 100mL beaker, add an equal volume of 2% chloroauric acid solution, place it in a 60℃ water bath, rotate the magnetic spindle at 600r / min, and after the water in the beaker has almost dried, place the sample in a 60℃ oven to dry, thus obtaining Au-loaded alumina.

[0051] Example 5

[0052] A. Weigh 8g of boehmite strip sample and place it in the reactor, seal it, and first introduce the protective gas into the reactor through a deoxygenation device to check the airtightness of the device. Methane was selected as the protective gas (M), which was introduced into the reactor after passing through the deoxygenation device. The flow rate ratio of methane to protective gas was controlled at 1:9 using a mass flow meter, ensuring a gas ratio of 10% CH4 / 90% N2 (protective gas) flowing through the reactor. A programmed temperature rise was used, increasing the temperature to 150℃ at a rate of 10℃ / min, adjusting the gas flow rate to 35mL / min, and the reaction time to 2h. Then, the reaction gas concentration was changed to 20% CH4 / 80% N2 (protective gas); the gas flow rate was changed to 50mL / min; and the temperature was increased to 550℃ at a rate of 10℃ / min, with a reaction time of 2h. After the reaction, the sample was cooled to room temperature, and quickly removed to obtain a reducing alumina support, which was then vacuum-packed for later use. The deoxygenation device used a 401 manganese-based deoxidizer for deoxygenation.

[0053] B. Place the sample from step A into a 50 mL sample tube, add an equal volume of 5% sodium chloropalladium solution, sonicate for 5 minutes, and then immerse the sample in a 70 °C oven for 16 h to obtain Pd-loaded alumina.

[0054] Example 6

[0055] A. Weigh 6g of powdered aluminum hydroxide sample and place it in the reactor, seal it, and first introduce the protective gas into the reactor through a deoxygenation device to check the airtightness of the device. Methane and ethane are selected as the M gas, which are introduced into the reactor after passing through the deoxygenation device. The flow rate ratio of methane, ethane, and protective gas is controlled at 1:1:3 using a mass flow meter, ensuring that the gas ratio flowing through the reactor is 20% CH4 / 20% C2H6 / 60% N2 (protective gas). A programmed temperature rise method is used, increasing the temperature to 500℃ at a rate of 10℃ / min, adjusting the gas flow rate to 35mL / min, and the reaction time is 3h. After the reaction is complete, cool to room temperature, quickly remove the sample, and obtain a reducing alumina carrier, which is then vacuum-packed for later use. The deoxygenation device utilizes a 401 manganese-based deoxidizer for deoxygenation.

[0056] B. Place the sample from step A into a 100mL beaker, add an equal volume of 2% sodium chloropalladium solution, place it in a 50℃ water bath, rotate the magnetic spinner at 400r / min, and after the water in the beaker has almost dried, place the sample in a 70℃ oven to dry, thus obtaining Pd-loaded alumina.

[0057] Example 7

[0058] A. Weigh 2g of spherical boehmite sample and place it in the reactor, seal it, and first introduce the protective gas into the reactor through a deoxygenation device to check the airtightness of the device. Methane and carbon monoxide are selected as the M gas, which is introduced into the reactor after passing through the deoxygenation device. The flow rate ratio of methane, carbon monoxide, and protective gas is controlled at 1:3:6 using a mass flow meter, ensuring a gas ratio of 10% CH4 / 30% CO / 60% N2 (protective gas) flowing through the reactor. A programmed temperature rise method is used, increasing the temperature to 550℃ at a rate of 10℃ / min, adjusting the gas flow rate to 15mL / min, and the reaction time is 4h. After the reaction, cool to room temperature, quickly remove the sample, and obtain a reducing alumina support, which is then vacuum-packed for later use. The deoxygenation device utilizes a 401 manganese-based deoxidizer for deoxygenation.

[0059] B. Place the sample from step A into a 50 mL sample tube, add an equal volume of 5% sodium chloropalladium solution, sonicate for 5 minutes, and then immerse the sample in an 80 °C oven for 24 h to obtain Pd-loaded alumina.

[0060] Example 8

[0061] A. Weigh 10g of spherical boehmite sample and place it in the reactor, seal it, and first introduce the protective gas into the reactor through a deoxygenation device to check the airtightness of the device. The M gas is selected as ethane and acetylene, which are introduced into the reactor after passing through the deoxygenation device. The flow rate ratio of ethane, acetylene, and protective gas is controlled at 4:1:5 using a mass flow meter, so that the gas ratio flowing through the reactor is 40% C2H6 / 10% C2H2 / 50% N2 (protective gas). A programmed temperature rise method is used, heating to 500℃ at a rate of 10℃ / min, adjusting the gas flow rate to 25mL / min, and the reaction time is 3h. After the reaction, cool to room temperature, quickly remove the sample, and obtain a reducing alumina support, which is then vacuum-packed for later use. The deoxygenation device uses a 401 manganese-based deoxidizer for deoxygenation.

[0062] B. Place the sample from step A into a 50 mL sample tube, add an equal volume of 0.1% sodium chloropalladium solution, sonicate for 5 minutes, and then immerse the sample in an 80 °C oven for 16 h to obtain Pd-loaded alumina.

[0063] Comparative Example

[0064] The comparative sample was prepared according to the parameters of Example 1, except that it was not treated with a carbon-containing mixed gas.

[0065] A. Weigh 10g of powdered boehmite sample and place it in a reactor. Introduce protective gas into the reactor through a deoxygenation device. Use a programmed temperature rise method, increasing the temperature to 450℃ at a rate of 5℃ / min. Adjust the gas flow rate to 35mL / min and the reaction time to 4h. This yields an alumina support.

[0066] B. Place the alumina support from step A into a 100mL beaker, add an equal volume of 0.1% sodium chloropalladium solution, place it in a 40℃ water bath, and rotate the magnetic spinner at 550r / min. After the water in the beaker has almost dried, place the sample in a 70℃ oven to dry, and obtain Pd-loaded alumina.

[0067] C. Place the Pd-loaded alumina obtained in step B in a tube furnace, set the reaction temperature to 250℃, and calcine it for 3 hours under a 10% H2 / N2 atmosphere to obtain the Pd / Al2O3 catalyst.

[0068] Application examples

[0069] The catalysts prepared in Example 1 and Comparative Example 1 were used in experiments on the half-hydrogenation reaction of acetylene:

[0070] Weigh 0.2g of catalyst and mix thoroughly with 1.8g of quartz sand with a particle size of 40-70 mesh. Load the catalyst mixture into a quartz reaction tube with a diameter of 10mm. The catalytic performance test temperature is 50-150℃, and the gas composition of the reactant gas is 0.71% C2H2 / 2.86% H2 / 70.72% C2H4 / 25.71% N2 (equilibrium gas). The test pressure is 1 bar, and the space velocity is 3800 h⁻¹. -1 The composition and content of reactants and products were analyzed by gas chromatography, and the data were processed using the normalization method. To ensure the accuracy of the test, results were recorded after reaching the specified temperature and holding for 30 minutes. Three sets of tests were performed, and the average value was taken as the catalytic performance data at that catalytic temperature. Results are shown below. Figure 8 .

[0071] Depend on Figure 8 It can be seen that, compared with Pd / Al2O3 catalysts prepared by traditional methods, Pd / Al2O3 catalysts prepared by impregnation in situ self-reduction method have better hydrogenation activity in the low temperature region.

Claims

1. A method for preparing a catalyst with reducing function on an alumina support using a carbon-containing mixed gas, characterized in that: Prepare according to the following steps: A: The alumina precursor is placed in a reactor and sealed. First, a protective gas is introduced into the reactor through a deoxygenation device. Then, carbon-containing gas M is introduced into the reactor after being deoxygenated through the deoxygenation device. The flow rates of carbon-containing gas M and the protective gas are controlled by a mass flow meter to adjust the ratio of reactant gases. After the reactant gases have been introduced for 8-15 minutes, the reactor is heated using a programmed temperature rise method at a rate of 2-15℃ / min, a reaction temperature of 400-600℃, a reaction time of 1-10 hours, and a reactant gas flow rate of 10mL / min-100mL / min. After the reaction is complete, the mixture is cooled to room temperature, and the sample is quickly removed, vacuum-packed, and ready for use, yielding a reducing alumina support with a γ-type crystal structure. The reaction gas consists of carbon-containing gas M and a protective gas, wherein the volume content of carbon-containing gas M is 5%-60%, and the remainder is a protective gas; The protective gas is an inert gas, such as nitrogen or argon. The deoxygenation device is a drying tube with added 401 manganese-based deoxidizer; The carbon-containing gas M is any one or more of CH4, C2H2, CO, C2H4, and C2H6; The alumina precursor is any one of spherical boehmite, bar-shaped boehmite, powdered boehmite, or powdered aluminum hydroxide. During the reaction in step A, carbon-containing gas molecules in the carbon-containing mixed gas adsorb onto the surface of the alumina precursor, inducing a change in its Al-O bond structure and activating its surface hydroxyl groups to generate active intermediates H*. Some of the active H* is removed, while the other part of the active intermediate migrates on the surface and re-stabilizes on the surface, forming a reducing Al-OH* bond structure. B: Add an equal volume of precious metal impregnation solution to the reducing alumina carrier obtained in step A, wherein the concentration of the precious metal solution is determined according to the content of precious metal required for the final product. For the formed alumina carrier, the formed alumina carrier is mixed evenly with the noble metal solution and placed in an oven to dry at 20-90℃ for 6-36 hours to obtain the alumina carrier loaded with noble metal elements. For powdered alumina carrier, the mixture of powdered alumina carrier and noble metal solution is placed in a water bath, and magnetic stirrer is added for stirring at a speed of 100-1000 rpm. When the solution is almost dry, it is placed in an oven to dry, thus obtaining alumina carrier loaded with noble metal elements. During the impregnation process, the metal cations gradually approach the surface of the support. Due to charge interaction, they migrate to the vicinity of the Al-OH* bond. The Al-OH* structure donates electrons to the metal cations, thereby reducing them to form metal atoms and obtaining the reduced noble metal catalyst, thus achieving simultaneous loading and reduction.

2. The method according to claim 1, characterized in that: The temperature program in step A has a reaction time of 2-6 hours and a reaction gas flow rate of 10 mL / min-60 mL / min. The volume content of carbon gas M in the reaction gas is 10%-40%, and the remainder is a protective gas; The carbon-containing gas M is any one, two, or three of CH4, C2H2, CO, C2H4, and C2H6; The alumina precursor is powdered aluminum hydroxide or powdered boehmite.

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