Bimetal hierarchical pore catalyst as well as preparation method and application thereof

Abstract

The invention provides a bimetallic hierarchical pore catalyst as well as a preparation method and application thereof, and belongs to the technical field of catalyst materials. The preparation method comprises the following steps: firstly, preparing a hierarchical pore ZSM-5 molecular sieve by taking organic alkali, a ZSM-5 molecular sieve and ammonia water as raw materials, improving the selectivity of a target product glyceraldehyde and prolonging the service life of a catalyst by virtue of a rich pore structure of the hierarchical pore ZSM-5 molecular sieve, and then loading metal M1 and metal M2 on the surface of the hierarchical pore ZSM-5 molecular sieve, the reaction activity and selectivity of the prepared catalyst for catalyzing polyol oxidation are enhanced by utilizing the synergistic effect of bimetals, the polyol oxidation reaction can be efficiently catalyzed under mild conditions to generate glyceraldehyde, and finally the bimetal hierarchical pore catalyst with excellent glyceraldehyde selectivity and catalytic stability is obtained. The defects of low glyceraldehyde selectivity, short catalyst life and the like in the prior art are overcome.

Description

Technical Field

[0001] The present invention relates to the technical field of catalyst materials, and particularly relates to a bimetallic hierarchical pore catalyst, a preparation method thereof, and an application thereof. Background Art

[0002] Glyceraldehyde is a simple organic compound with the chemical formula C3H6O3 and belongs to aldehyde compounds. It is an oxidation product of glycerol and also an important intermediate. It belongs to α-hydroxy aldehyde and is an important intermediate in the synthesis of disaccharides and polysaccharides, playing an important role in biology and chemical synthesis.

[0003] Glyceraldehyde is a key intermediate in sugar metabolism, participating in glycolysis and gluconeogenesis processes, especially playing an important role in energy generation and metabolite conversion. In addition, as a highly reducing chemical, glyceraldehyde is widely used in organic synthesis, especially in the synthesis of chiral compounds, sugar alcohols, amino acids, drugs, and other bioactive molecules. Due to its reactivity, glyceraldehyde can also be used in catalytic reactions, esterification reactions, and reduction reactions, becoming an important intermediate for synthesizing various chemicals. In biological research, glyceraldehyde is used as a marker for metabolic pathways and is also of great significance for the research of diseases such as diabetes.

[0004] Currently, glyceraldehyde is mainly prepared by biological synthesis methods or chemical synthesis methods. Biological synthesis methods usually rely on microbial fermentation. Although environmentally friendly and energy-efficient, the yield and separation and purification processes lead to increased costs. Chemical synthesis routes can achieve large-scale production, but often involve complex reaction steps and expensive catalysts, and may produce harmful by-products, increasing the environmental burden of production.

[0005] In the existing publicly disclosed technologies for the selective oxidation of polyols to prepare glyceraldehyde, most use heterogeneous catalysts and biological enzymes. Yangzhou Polytechnic Institute provided a fullerene zinc oxide selenium C 60 / ZnO / Se composite catalyst and its application in the synthesis of glyceraldehyde in Patent CN108620095B. This method is simple to operate, has mild conditions, and the glyceraldehyde yield is above 90%. Jiangnan University disclosed a method for producing D-glyceraldehyde in Patent CN111172123A. Glycerol is converted into D-glyceraldehyde by the sugar alcohol oxidase AldO. The amino acid sequence of the sugar alcohol oxidase AldO of Streptomyces coelicolor is codon-optimized and expressed in Escherichia coli cells. This enzyme can convert inexpensive glycerol into D-glyceraldehyde and has good catalytic efficiency. The reaction temperature is 25-45°C, and the conversion rate is above 95%.

[0006] Developing efficient, economical, and environmentally friendly methods for synthesizing glyceraldehyde remains a hot and difficult issue in current research. Utilizing biocatalytic reactions, green solvents, etc. is also the key to solving cost and environmental problems. The selection and utilization efficiency of bio-based raw materials (such as glycerol, glucose, etc.) as substrates are also an important research direction. Summary of the Invention

[0007] The purpose of the present invention is to provide a bimetallic hierarchical pore catalyst, its preparation method, and application. The bimetallic hierarchical pore catalyst provided by the present invention can efficiently catalyze the oxidation reaction of polyols to produce glyceraldehyde under mild conditions, with excellent glyceraldehyde selectivity and catalytic stability, overcoming the defects of low glyceraldehyde selectivity and short catalyst life in the prior art.

[0008] To achieve the above invention purpose, the present invention provides the following technical solutions:

[0009] The present invention provides a preparation method of a bimetallic hierarchical pore catalyst, including the following steps:

[0010] (1) Using an organic base, ZSM-5 molecular sieve, and ammonia water as raw materials, a hierarchical pore ZSM-5 molecular sieve is prepared;

[0011] (2) Mixing the hierarchical pore ZSM-5 molecular sieve prepared in step (1), a soluble salt of metal M1, a soluble salt of metal M2, and deionized water, and successively performing stirring, calcination, and hydrogen reduction to obtain a bimetallic hierarchical pore catalyst.

[0012] Preferably, the organic base in step (1) is one or more of piperidine, tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetramethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, and benzyltrimethylammonium hydroxide.

[0013] Preferably, the preparation method of the hierarchical pore ZSM-5 molecular sieve in step (1) includes the following steps: Dissolving the organic base in deionized water, then adding the ZSM-5 molecular sieve, and then adjusting the pH to 8-11 with ammonia water, and successively performing stirring, crystallization, post-treatment, and calcination to obtain a hierarchical pore ZSM-5 molecular sieve.

[0014] Preferably, the crystallization is carried out in a hydrothermal autoclave, the crystallization temperature is 180-280 °C, and the crystallization time is 10-76 h.

[0015] Preferably, in step (2), the metal element M1 in the soluble salt of metal M1 is at least one of nickel, cobalt, platinum, and rhodium; the metal element M2 in the soluble salt of metal M2 is at least one of magnesium, cerium, zinc, iron, and copper; the molar ratio of the metal element M1 to the metal element M2 is (2-2000):1.

[0016] Preferably, the soluble salt of the metal M1 is at least one of nickel nitrate hexahydrate, nickel acetate, cobalt sulfate heptahydrate, cobalt nitrate hexahydrate, chloroplatinic acid, potassium chloroplatinate, rhodium nitrate, and rhodium trichloride hydrate; the soluble salt of the metal M2 is at least one of magnesium chloride hexahydrate, cerium nitrate hexahydrate, zinc nitrate, zinc sulfate, iron chloride hexahydrate, iron nitrate hexahydrate, copper chloride, and copper nitrate.

[0017] Preferably, the total loading of the metal element M1 and the metal element M2 in the bimetallic hierarchical pore catalyst in the step (2) is 2-20 wt%.

[0018] Preferably, the calcination temperature in the step (2) is 400-700 °C, and the calcination time is 2-5 h.

[0019] The present invention also provides a bimetallic hierarchical pore catalyst prepared by the preparation method described in any one of the above technical solutions.

[0020] The present invention also provides an application of the bimetallic hierarchical pore catalyst described in the above technical solution in the catalytic preparation of glyceraldehyde from polyols.

[0021] The present invention provides a preparation method of a bimetallic hierarchical pore catalyst. First, an organic base, ZSM-5 molecular sieve, and ammonia water are used as raw materials to prepare a hierarchical pore ZSM-5 molecular sieve. The rich pore structure of the hierarchical pore ZSM-5 molecular sieve improves the selectivity of the target product glyceraldehyde and the service life of the catalyst. Then, the metal M1 and the metal M2 are loaded on the surface of the hierarchical pore ZSM-5 molecular sieve. The synergistic effect of the bimetal enhances the reaction activity and selectivity of the prepared catalyst for the oxidation of polyols, and can efficiently catalyze the oxidation reaction of polyols to generate glyceraldehyde under mild conditions. Finally, a bimetallic hierarchical pore catalyst with excellent glyceraldehyde selectivity and catalytic stability is obtained, overcoming the defects of low glyceraldehyde selectivity and short catalyst life in the prior art. Description of the Drawings

[0022] Figure 1 It is a TEM image of the bimetallic hierarchical pore catalyst prepared in Example 2 of the present invention. Detailed Embodiments

[0023] The present invention provides a preparation method of a bimetallic hierarchical pore catalyst, comprising the following steps:

[0024] (1) Using an organic base, ZSM-5 molecular sieve, and ammonia water as raw materials, prepare a hierarchical pore ZSM-5 molecular sieve;

[0025] (2) Mix the hierarchical pore ZSM-5 molecular sieve prepared in the step (1), the soluble salt of the metal M1, the soluble salt of the metal M2, and deionized water, and successively carry out stirring, calcination, and hydrogen reduction to obtain a bimetallic hierarchical pore catalyst.

[0026] In the present invention, unless otherwise specified, the raw materials used are all conventional commercially available products in the art.

[0027] The present invention uses an organic base, ZSM-5 molecular sieve and ammonia water as raw materials to prepare a hierarchical pore ZSM-5 molecular sieve.

[0028] In the present invention, the organic base is preferably one or more of piperidine, tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetramethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, benzyltrimethylammonium hydroxide.

[0029] In the present invention, the method for preparing the hierarchical pore ZSM-5 molecular sieve preferably includes the following steps: dissolving the organic base in deionized water, adding the ZSM-5 molecular sieve, and then adjusting the pH to 8-11 with ammonia water, followed by stirring, crystallization, post-treatment and calcination to obtain the hierarchical pore ZSM-5 molecular sieve.

[0030] In the present invention, the solid-liquid ratio of the ZSM-5 molecular sieve to the organic base is preferably 1 g:(3-240) mL, more preferably 1 g:(5-200) mL. The present invention controls the solid-liquid ratio of the ZSM-5 molecular sieve to the organic base solution within the above range to ensure that the organic base can fully play its role in selectively desiliconizing the molecular sieve to form hierarchical pores.

[0031] In the present invention, the ammonia water is preferably ammonia water with a mass concentration of 25%. In the present invention, the temperature of the stirring is preferably 25-80 °C; the time of the stirring is preferably 20-120 min; the speed of the stirring is preferably 500-2000 r / min. The present invention makes the components mix evenly by stirring.

[0032] In the present invention, the crystallization is preferably carried out in a hydrothermal kettle, more preferably in a hydrothermal kettle with a stainless steel outer shell; the temperature of the crystallization is preferably 180-280 °C, more preferably 200-250 °C; the time of the crystallization is preferably 10-76 h, more preferably 12-72 h. The present invention protects the aluminum in the molecular sieve while selectively removing silicon by the organic base during crystallization, reducing the damage to the molecular sieve crystals.

[0033] In the present invention, the post-treatment is preferably centrifugation and drying in sequence. In the present invention, the rotation speed of the centrifugation is preferably 5000-20000 rpm, and the time of the centrifugation is preferably 5-10 min. The present invention realizes solid-liquid separation by centrifugation. In the present invention, the temperature of the drying is preferably 25-80 °C, and the time of the drying is preferably 2-12 h. The present invention removes the residual reagents by drying.

[0034] In the present invention, the calcination temperature is preferably 400 - 700 °C, the calcination time is preferably 2 - 5 h; the calcination atmosphere is preferably air or nitrogen; the heating rate of the calcination is preferably 2 - 10 °C / min. In the present invention, by controlling the calcination temperature, time, atmosphere and heating rate within the above ranges, the organic base is fully removed to obtain a hierarchical pore ZSM-5 molecular sieve with better purity and quality.

[0035] After obtaining the hierarchical pore ZSM-5 molecular sieve, the present invention mixes the hierarchical pore ZSM-5 molecular sieve, a soluble salt of metal M1, a soluble salt of metal M2 and deionized water, and successively performs stirring, calcination and hydrogen reduction to obtain a bimetallic hierarchical pore catalyst.

[0036] In the present invention, the metal element M1 in the soluble salt of metal M1 is preferably at least one of nickel, cobalt, platinum, and rhodium; the metal element M2 in the soluble salt of metal M2 is preferably at least one of magnesium, cerium, zinc, iron, and copper. In the present invention, the soluble salt of metal M1 is preferably at least one of nickel nitrate hexahydrate, nickel acetate, cobalt sulfate heptahydrate, cobalt nitrate hexahydrate, chloroplatinic acid, potassium chloroplatinate, rhodium nitrate, and rhodium(III) chloride hydrate; the soluble salt of metal M2 is preferably at least one of magnesium chloride hexahydrate, cerium nitrate hexahydrate, zinc nitrate, zinc sulfate, iron(III) chloride hexahydrate, iron(III) nitrate hexahydrate, copper chloride, and copper nitrate. By using the soluble salts of metal M1 and metal M2 of the above types, the present invention utilizes the synergistic effect of the bimetal to reduce the cost of the catalyst.

[0037] In the present invention, the molar ratio of metal element M1 to metal element M2 is preferably (2 - 2000):1. By controlling the molar ratio of metal element M1 to metal element M2, the present invention gives full play to the synergistic effect of the bimetal and improves the selectivity and yield of the product.

[0038] In the present invention, the total loading amount of metal element M1 and metal element M2 in the bimetallic hierarchical pore catalyst is preferably 2 - 20 wt%. By controlling the total loading amount of metals M1 and M2 in the bimetallic hierarchical pore catalyst, the prepared catalyst plays a better role in catalyzing the preparation of glyceraldehyde from polyols.

[0039] In the present invention, the stirring is preferably carried out by stirring the mixture at a constant temperature of 25 - 85 °C until the surface is dried. By stirring, the present invention gradually dries the mixture, which is beneficial to the dispersion of the metal active components on the carrier and the interaction between the two.

[0040] In the present invention, the calcination temperature is preferably 400 - 700 °C, the calcination time is preferably 2 - 5 h, more preferably 2.5 - 4 h. By calcination, the present invention removes water and other impurities during the synthesis of the catalyst.

[0041] In the present invention, the hydrogen reduction is preferably carried out in a tubular furnace with a hydrogen flow rate of 5 to 50 mL / min; the temperature of the hydrogen reduction is preferably 130 to 300° C., more preferably 150 to 250° C.; the time of the hydrogen reduction is preferably 1 to 8 hours, more preferably 2 to 6 hours. The present invention reduces the metal components in the catalyst from ions to active metal elements through hydrogen reduction to improve the catalytic activity of the catalyst.

[0042] The present invention also provides a bimetallic multi-level porous catalyst prepared by the preparation method described in any one of the above technical solutions.

[0043] The present invention also provides the use of the bimetallic multi-level porous catalyst described in the above technical solution in catalyzing the preparation of glyceraldehyde from polyols.

[0044] In the present invention, the use of the bimetallic multilevel porous catalyst in catalyzing the preparation of glyceraldehyde from polyols preferably includes the following steps: using polyols as raw materials, carrying out an oxidation reaction in a high-pressure reactor in an oxygen atmosphere in the presence of the bimetallic multilevel porous catalyst to obtain glyceraldehyde.

[0045] In the present invention, the polyol is preferably an alcohol containing two or more hydroxyl groups in the molecule, and more preferably at least one of glycerol, ethylene glycol, glucose and glucitol.

[0046] In the present invention, the oxygen pressure is preferably 0.3-5 MPa, more preferably 0.5-3 MPa; the oxidation reaction temperature is preferably 40-175°C, more preferably 50-125°C; the oxidation reaction time is preferably 1-8 h, more preferably 2-6 h.

[0047] The technical solutions in the present invention will be described clearly and completely below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0048] Example 1

[0049] A method for preparing a bimetallic multi-level porous catalyst, also known as a Ni-Mg / ZSM-5 catalyst, comprises the following steps:

[0050] (1) Weigh 2 g of ZSM-5 molecular sieve (purchased from Nankai Catalyst Factory). Weigh 25 g of organic base in a beaker, add deionized water to make up to 80 mL, add the ZSM-5 molecular sieve, add ammonia water (mass concentration of 25%) to adjust the pH to 8 - 11, stir at a constant temperature of 30 °C at a speed of 500 r / min for 120 min. After stirring, transfer the solution to a hydrothermal kettle with a stainless-steel shell, crystallize at 150 °C for 24 h, then centrifuge and separate. After drying at 70 °C for 6 h, place it in a muffle furnace at 450 °C for roasting, with a roasting time of 3 h and a heating rate of 2 - 10 °C / min to obtain hierarchical pore ZSM-5 molecular sieve;

[0051] (2) Weigh 1 g of nickel nitrate hexahydrate (purchased from Macklin), mix it with the hierarchical pore ZSM-5 molecular sieve obtained in step (1) in 20 mL of deionized water. Then, weigh the corresponding mass of magnesium chloride hexahydrate according to the molar ratio of nickel to magnesium of 50:1 and add it to the above-mentioned mixture. Stir the mixture at a constant temperature of 50 °C at a speed of 800 rpm until the surface is dried to obtain solid A. Place solid A in a muffle furnace and heat it to 450 °C at a heating rate of 3 °C / min for roasting for 3 h to obtain solid B. Place solid B in a small porcelain bowl and place it in a tubular furnace with a hydrogen flow rate of 15 mL / min for reduction. The reduction temperature is 220 °C and the reduction time is 6 h to obtain the Ni-Mg / ZSM-5 catalyst.

[0052] Example 2

[0053] A preparation method of a bimetallic hierarchical pore catalyst, also known as the Ni-Zn / ZSM-5 catalyst:

[0054] Prepared according to the method of Example 1. The difference from Example 1 is that in step (2), the soluble salt component of metal M2 is changed to zinc nitrate (purchased from Macklin), and the molar ratio of nickel to zinc is 50:1.

[0055] Figure 1 This is the TEM image of the bimetallic hierarchical pore catalyst prepared in Example 2 of the present invention. As Figure 1 can be seen, the metal components are successfully loaded onto the molecular sieve support.

[0056] Example 3

[0057] A preparation method of a bimetallic hierarchical pore catalyst, also known as the Ni-Zn / ZSM-5 catalyst:

[0058] Prepared according to the method of Example 1. The difference from Example 1 is that in step (2), the soluble salt component of metal M2 is changed to zinc nitrate (purchased from Macklin), and the molar ratio of nickel to zinc is 50:1.

[0059] Example 4

[0060] Preparation method of a bimetallic hierarchical pore catalyst, also known as Ni-Cu / ZSM-5 catalyst:

[0061] Prepared according to the method of Example 1. Different from Example 1, in step (2), the soluble salt component of metal M2 is changed to copper nitrate (purchased from Macklin), and the molar ratio of nickel to copper is 50:1.

[0062] Example 5

[0063] Preparation method of a bimetallic hierarchical pore catalyst, also known as Pt-Cu / ZSM-5 catalyst:

[0064] Prepared according to the method of Example 1. Different from Example 1, in step (2), the soluble salt component of metal M1 is changed to chloroplatinic acid (purchased from Macklin), and the molar ratio of platinum to copper is 50:1.

[0065] Example 6

[0066] Preparation method of a bimetallic hierarchical pore catalyst, also known as Pt-Fe / ZSM-5 catalyst:

[0067] Prepared according to the method of Example 1. Different from Example 1, in step (2), the soluble salt component of metal M2 is changed to ferric nitrate hexahydrate (purchased from Macklin), and the molar ratio of platinum to iron is 50:1.

[0068] Example 7

[0069] Preparation method of a bimetallic hierarchical pore catalyst, also known as Rh-Fe / ZSM-5 catalyst:

[0070] Prepared according to the method of Example 1. Different from Example 1, in step (2), the soluble salt component of metal M1 is changed to rhodium nitrate (purchased from Macklin), and the molar ratio of rhodium to iron is 50:1.

[0071] Example 8

[0072] Preparation method of a bimetallic hierarchical pore catalyst, also known as Rh-Ce / ZSM-5 catalyst:

[0073] Prepared according to the method of Example 1. Different from Example 1, in step (2), the soluble salt component of metal M2 is changed to cerium nitrate hexahydrate (purchased from Macklin), and the molar ratio of rhodium to cerium is 50:1.

[0074] Example 9

[0075] Preparation method of a bimetallic hierarchical pore catalyst, also known as Co-Ce / ZSM-5 catalyst:

[0076] Prepared according to the method of Example 1. The difference from Example 1 is that in step (2), the soluble salt component of metal M1 is changed to cobalt sulfate heptahydrate (purchased from Macklin), and the molar ratio of cobalt to cerium is 50:1.

[0077] Example 10

[0078] A preparation method of a bimetallic hierarchical pore catalyst, also known as a Co-Cu / ZSM-5 catalyst: Prepared according to the method of Example 1. The difference from Example 1 is that in step (2), the soluble salt component of metal M2 is changed to copper nitrate (purchased from Macklin), and the molar ratio of nickel to zinc is 50:1.

[0079] Comparative Example 1

[0080] Preparation method of Ni-Mg / ZSM-5-A catalyst

[0081] Prepared according to the method of Example 1. The difference from Example 1 is that ordinary ZSM-5 molecular sieve is used and no hierarchical pore modification is carried out. The specific steps are as follows:

[0082] S1, Weigh 1 g of nickel nitrate hexahydrate (purchased from Macklin), mix it with 2 g of ZSM-5 molecular sieve (purchased from Nankai Catalyst Plant) in 20 mL of deionized water, and then weigh the corresponding mass of magnesium chloride hexahydrate according to the molar ratio of nickel to magnesium of 50:1 and add it to the above-mentioned mixed solution. Stir the mixed solution at a constant temperature of 50 °C at a rotation speed of 800 rpm until the surface is evaporated to dryness to obtain solid A. Place solid A in a muffle furnace at 450 °C for calcination. The calcination time is 3 h, and the heating rate is 3 °C / min to obtain solid B;

[0083] S2, Place solid B in a small porcelain bowl, place it in a tubular furnace with a hydrogen flow rate of 15 mL / min for reduction. The reduction temperature is 220 °C, and the reduction time is 6 h to obtain the Ni-Mg / ZSM-5-A catalyst.

[0084] Application Example 1

[0085] Application of the bimetallic hierarchical pore catalyst prepared in Example 1 in the preparation of glyceraldehyde from polyols. Steps:

[0086] Dry the bimetallic hierarchical pore catalyst prepared in Example 1 at a constant temperature of 80 °C for 6 h. After cooling to room temperature, weigh 0.1 g of the catalyst and add it to a stainless steel autoclave with a 20 ml quartz inner liner. Then add 10 mL of 0.2 mol / L glycerol solution and 0.1 g of potassium hydroxide in sequence. Using H2O as the solvent, O2 at 1.2 MPa, the reaction temperature is 70 °C, and the reaction time is 6 h to obtain the product glyceraldehyde. Perform gas chromatography analysis on the product, and the results are shown in Table 1.

[0087] Application Examples 2 - 6

[0088] Glyceraldehyde was prepared according to the method of Application Example 1. The difference from Application Example 1 was that in Application Examples 2 - 6, the corresponding catalysts prepared in Example 2, Example 5, Example 7, Example 10 and Comparative Example 1 were respectively used to catalyze the oxidation of polyol to prepare glyceraldehyde, and the product was analyzed by gas chromatography. The results are shown in Table 1. In Table 1, GLY is glycerol, GLYa is the selectivity of glyceric acid, and GLYb is the selectivity of glyceraldehyde.

[0089] Table 1 Gas Chromatography Analysis Results of the Products Prepared in Application Examples 1 - 6

[0090] Preparation of catalyst Name of the catalyst GLY conversion rate (%) GLYa / % GLYb / % Example 1 Ni-Mg / ZSM-5 72.1 15.0 82.3 Example 2 Ni-Zn / ZSM-5 62.5 18.6 74.7 Example 5 Pt-Cu / ZSM-5 75.3 16.3 87.5 Example 7 Rh-Fe / ZSM-5 70.6 21.7 73.2 Example 10 Co-Cu / ZSM-5 36.3 10.5 50.1 Comparative Example 1 Ni-Mg / ZSM-5-A 46.8 22.4 59.9

[0091] It can be seen from Table 1 that compared with the catalyst prepared in Comparative Example 1 without hierarchical pores and untreated, the bimetallic hierarchical pore catalysts prepared in Examples 1 - 7 of the present invention with hierarchical pores have more excellent glycerol conversion and glyceraldehyde selectivity due to their richer pore structures.

[0092] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A preparation method of a bimetallic hierarchical pore catalyst, characterized in that It includes the following steps: (1) Using an organic base, ZSM-5 molecular sieve, and ammonia water as raw materials, a hierarchical pore ZSM-5 molecular sieve is prepared; (2) Mixing the hierarchical pore ZSM-5 molecular sieve prepared in step (1), a soluble salt of metal M1, a soluble salt of metal M2, and deionized water, followed by stirring, calcination, and hydrogen reduction in sequence to obtain a bimetallic hierarchical pore catalyst.

2. The preparation method according to claim 1, characterized in that, In step (1), the organic base is one or more of piperidine, tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetramethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, and benzyltrimethylammonium hydroxide.

3. The preparation method according to claim 1, characterized in that, The preparation method of the hierarchical pore ZSM-5 molecular sieve in step (1) includes the following steps: Dissolving the organic base in deionized water, adding the ZSM-5 molecular sieve, then adjusting the pH to 8-11 with ammonia water, and performing stirring, crystallization, post-treatment, and calcination in sequence to obtain a hierarchical pore ZSM-5 molecular sieve.

4. The preparation method according to claim 3, characterized in that, The crystallization is carried out in a hydrothermal autoclave, the temperature of the crystallization is 180-280 °C, and the time of the crystallization is 10-76 h.

5. The preparation method according to claim 1, characterized in that, In step (2), the metal element M1 in the soluble salt of metal M1 is at least one of nickel, cobalt, platinum, and rhodium; the metal element M2 in the soluble salt of metal M2 is at least one of magnesium, cerium, zinc, iron, and copper; the molar ratio of the metal element M1 to the metal element M2 is (2-2000):

1.

6. The preparation method according to claim 1 or 5, characterized in that The soluble salt of metal M1 is at least one of nickel nitrate hexahydrate, nickel acetate, cobalt sulfate heptahydrate, cobalt nitrate hexahydrate, chloroplatinic acid, potassium chloroplatinate, rhodium nitrate, and rhodium trichloride hydrate; the soluble salt of metal M2 is at least one of magnesium chloride hexahydrate, cerium nitrate hexahydrate, zinc nitrate, zinc sulfate, iron chloride hexahydrate, iron nitrate hexahydrate, copper chloride, and copper nitrate.

7. The preparation method according to claim 1, characterized in that, In step (2), the total loading amount of the metal element M1 and the metal element M2 in the bimetallic hierarchical pore catalyst is 2-20 wt%.

8. The preparation method according to claim 1, wherein In step (2), the temperature of the calcination is 400-700 °C, and the time of the calcination is 2-5 h.

9. A bimetallic hierarchical pore catalyst prepared by the preparation method according to any one of claims 1-8.

10. Use of the bimetallic hierarchical pore catalyst according to claim 9 in the catalytic preparation of glyceraldehyde from polyols.

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