Preparation method and application of three-dimensional hierarchical ordered mesoporous zeolite confined NiCo alloy catalyst

Abstract

The application discloses a preparation method and application of a three-dimensional hierarchical ordered mesoporous zeolite limited NiCo alloy catalyst, and belongs to the technical field of lignin model compound catalytic upgrading. The catalyst forms a bimetallic active component by using metal Ni and Co, and forms a coating limitation for the active component in the process of synthesizing three-dimensional hierarchical ordered mesoporous 3DZSM-5 zeolite, so that the prepared catalyst has small metal particle size and high dispersity. The existence of the three-dimensional hierarchical ordered mesopore is beneficial to the contact, diffusion and transfer of reactants in the pore. The catalyst prepared by the application is used for preparing 2-methoxy-4-methylphenol by carrying out vanillin hydrodeoxygenation, and excellent catalytic performance is exhibited. In the recycling process of the catalyst, there is almost no metal leaching, subsequent separation is simple, cost is low, and the catalyst is beneficial to industrial production.

Description

TECHNICAL FIELD

[0001] The application relates to a preparation method and application of a three-dimensional hierarchical ordered mesoporous zeolite confined NiCo alloy catalyst, and belongs to the technical field of lignin model compound catalytic upgrading. BACKGROUND

[0002] With the decrease of fossil energy reserves and the increase of material source demand, biomass resources as an alternative renewable clean energy have attracted widespread attention. Vanillin from lignin is considered as a potential biomass feedstock for the production of 2-methoxy-4-methylphenol (MMP), which has a wide application not only as a high energy density fuel but also as an important intermediate for the synthesis of drugs and fragrances. In the past decade, many efficient catalysts for HDO reaction have been designed and synthesized. Due to their high activity, noble metal catalysts such as Pt, Pd and Au-based catalysts have been widely studied. However, the poor selectivity of side reactions and the high cost and low reserves of noble metals greatly limit the large-scale application of noble metals. In recent years, bimetallic catalysts based on alloy nanoparticles (NPs) are considered to be an effective method to improve the catalytic performance, especially Ni-based catalysts. However, the catalytic performance of bimetallic catalysts is restricted by many factors, such as metal loading, particle dispersion, size and interaction with the support.

[0003] ZSM-5 zeolite as a common metal support has adjustable acidity, high surface area and excellent thermal / hydrothermal stability, and is widely used in catalysis and adsorption fields. However, due to the limited interaction between the metal and the support, the metal species loaded on the surface are prone to agglomeration during the catalytic reaction, which reduces the utilization rate of metal active sites. Confining metal active sites inside the zeolite is an effective strategy to solve this problem. However, the narrow microporous structure often restricts the diffusion mass transfer performance of large-volume reaction substrates, thereby reducing the accessibility of internal metal active sites. Designing hierarchical porous zeolites with microporous and mesoporous structures is an effective optimization strategy to shorten the diffusion path and solve the diffusion limitation. In existing reports, most of the synthesized hierarchical ZSM-5 zeolites are disordered mesoporous structures, and the pore size is difficult to match the reaction substrate size, which makes it difficult to maximize the utilization of metal sites inside the pore and reduces the catalytic activity. In addition, the disordered structure in the mesoporous pore structure also limits the diffusion of the substrate, leading to a series of side reactions and reducing the selectivity of the product. Therefore, it is urgent to synthesize ordered mesoporous hierarchical zeolite confined bimetallic catalysts. SUMMARY

[0004] [TECHNICAL PROBLEM]

[0005] The present application solves the problem that the catalyst for synthesizing 2-methoxy-4-methylphenol in the prior art has poor stability due to a disordered mesoporous structure, resulting in poor recycling performance, low separation efficiency, low catalytic activity and low product selectivity in the synthesis process.

[0006] [Technical scheme]

[0007] To solve the above problems, the present application provides a preparation method and application of a three-dimensional hierarchical ordered mesoporous zeolite confined NiCo alloy catalyst. The catalyst is first synthesized by polystyrene microspheres (PS) templates, and then by using a steam seed assisted colloidal crystal template (SAC) method to confine amine-coordinated metals in three-dimensional hierarchical ordered mesoporous zeolites to obtain a NiCo@3DZSM-5 catalyst. The catalyst has excellent stability, can be recycled, can be magnetically separated, has low cost and other advantages.

[0008] The first object of the present application is to provide a preparation method of a three-dimensional hierarchical ordered mesoporous zeolite confined NiCo bimetallic catalyst, which specifically comprises the following steps:

[0009] (1) mixing styrene and NaOH solution and stirring, then separating the oil and water two phases until the solution is no longer red, to obtain refined styrene;

[0010] (2) dissolving the refined styrene prepared in step (1) and polyvinylpyrrolidone (mw=55000) in deionized water, then adding styrene and keeping stirring, then deoxygenating by nitrogen bubbling treatment, adding potassium persulfate aqueous solution to the mixture, and obtaining polystyrene ball template by centrifugation;

[0011] (3) mixing tetrapropylammonium hydroxide, anhydrous ethanol, tetraethyl orthosilicate and deionized water, stirring, then transferring to an autoclave, and obtaining ZSM-5 seed solution after hydrothermal treatment;

[0012] (4) mixing aluminum nitrate, tetrapropylammonium hydroxide, anhydrous ethanol and deionized water, then adding tetraethyl orthosilicate and ZSM-5 seed solution to form a mixed solution;

[0013] (5) adding nickel precursor and cobalt precursor solution coordinated with complexing agent, polystyrene ball template to the mixed solution prepared in step (4), and obtaining solid powder by vacuum evaporation;

[0014] (6) transferring the solid powder of step (5) to a stainless steel autoclave, hydrothermally treating, cooling, centrifuging, vacuum drying, high-temperature calcining, and then reducing in H2 atmosphere to obtain a three-dimensional mesoporous zeolite confined NiCo alloy catalyst.

[0015] In an embodiment of the present application, in step (1), the concentration of NaOH solution is 0.05-0.15 M, and further preferably 0.08-0.1 M.

[0016] In an embodiment of the present application, in step (1), the volume ratio of styrene to NaOH solution is 10:2-5, and further preferably 10:3.

[0017] In an embodiment of the present application, in step (2), the addition ratio of purified styrene, polyvinylpyrrolidone, deionized water, and styrene is 10-50 mL:0.1-0.5 g:200-700 mL:10-50 mL, and further preferably 25-30 mL:0.2-0.3 g:300-400 mL:20-30 mL.

[0018] In an embodiment of the present application, in step (2), the nitrogen bubbling time is 0.5-4 h, and further preferably 1-1.5 h, and the temperature is 50-100℃.

[0019] In an embodiment of the present application, in step (3), the molar ratio of tetrapropylammonium hydroxide, anhydrous ethanol, tetraethyl orthosilicate, and deionized water is 0.32-0.37:1:0.25:4.5-5.0, and further preferably 0.35:1:0.25:4.8; the stirring time is 12-48 h, and further preferably 24-28 h; the hydrothermal treatment temperature is 60-120℃, and further preferably 70-80℃; and the hydrothermal time is 48-120 h, and further preferably 72-78 h.

[0020] In an embodiment of the present application, in step (4), the molar ratio of aluminum nitrate, tetrapropylammonium hydroxide, anhydrous ethanol, and deionized water is 0.0048:0.15:1:4.8; the addition amount of tetraethyl orthosilicate and ZSM-5 seed solution is 4.5-7.5 g:3-7 mL; and the molar ratio of tetraethyl orthosilicate to aluminum nitrate is 45-75:1.

[0021] In an embodiment of the present application, in step (5), the complexing agent is one of ethylenediamine, ethylenediaminetetraacetic acid, 1,3-propanediaminetetraacetic acid, and triethylenediamine, and is preferably ethylenediamine.

[0022] In an embodiment of the present application, in step (5), the nickel precursor is one of Ni(NO3)2·6H2O, NiCl2·6H2O, and Ni(CH3COO)2·4H2O, and is preferably Ni(NO3)2·6H2O; and the cobalt precursor is one of Co(NO3)2·6H2O, CoCl2·6H2O, and Co(CH3COO)2·4H2O, and is preferably Co(NO3)2·6H2O.

[0023] In one embodiment of the present application, in step (5), the molar ratio of the nickel precursor, the cobalt precursor and the complexing agent is 1:0.5-3:20, preferably 1:1-1.5:20.

[0024] In one embodiment of the present application, in step (6), the reactor is equipped with a suspended metal mesh, and water is provided at the bottom to avoid direct contact with the precursors and to generate a saturated vapor environment.

[0025] In one embodiment of the present application, in step (6), the hydrothermal treatment temperature is 60-120℃, further preferably 70-80℃; the hydrothermal time is 48-120h, further preferably 72-78h.

[0026] In one embodiment of the present application, in step (6), the calcination temperature is 500-800℃, further preferably 550-600℃; the calcination time is 3-8h, further preferably 6-7h; the reduction temperature is 400-700℃, further preferably 500-550℃, and the reduction time is 1-5h, further preferably 2-3h.

[0027] Another object of the present application is to provide a three-dimensional hierarchical ordered mesoporous zeolite confined NiCo alloy catalyst prepared by the above method.

[0028] The present application also provides the use of the three-dimensional hierarchical ordered mesoporous zeolite confined NiCo alloy catalyst described above in the vanillin hydrodeoxygenation reaction.

[0029] In one embodiment of the present application, in the vanillin hydrodeoxygenation reaction, the three-dimensional hierarchical ordered mesoporous zeolite confined NiCo alloy catalyst is used in the vanillin hydrodeoxygenation reaction, the amount of vanillin and catalyst used is 1-5mmol:0.05-0.2g, the reaction temperature is 120-220℃, the hydrogen pressure is 0.5-2.5MPa, the reaction is carried out for 1-3h, and the solvent is one of deionized water, methanol, ethanol, formic acid and isopropanol.

[0030] [Advantages]

[0031] (1) The three-dimensional hierarchical ordered mesoporous zeolite confined NiCo alloy catalyst described in the present application has a synergistic effect between the active components Ni and Co species, which ensures the activity of the catalyst; in addition, the use of non-noble metals as active components has high economic value; in addition, by introducing 3DZSM-5 zeolite, the active components are confined and coated, which further improves the dispersion of the active components and enhances the interaction between the metal and the carrier.

[0032] (2) The catalyst has another advantage that the active component is protected by a limited mode to inhibit the loss of the active component, the catalyst has a long service life and can be used repeatedly, and the production cost is greatly reduced.

[0033] (3) The process for preparing 2-methoxy-4-methylphenol from vanillin is simple, the reaction conditions are mild, the product is easy to separate, and the industrial scale production is easy.

[0034] (4) The zeolite synthesized by using polystyrene balls as a template has a uniform pore size and a three-dimensional ordered structure, which is beneficial to the contact, diffusion and transfer of reactants in the pore.

[0035] (5) The three-dimensional hierarchical ordered mesoporous zeolite limited NiCo alloy catalyst is synthesized by using polystyrene microspheres as a template, and the problems of low catalytic activity and low product selectivity caused by the disordered mesoporous structure of the hierarchical ZSM-5 zeolite in the prior art are solved.

[0036] (6) The catalyst prepared by the method has good cycle performance, and the yield of the product 2-methoxy-4-methylphenol is 100% in the hydrogenation and deoxidation reaction of vanillin. BRIEF DESCRIPTION OF DRAWINGS

[0037] Figure 1 is a reaction path diagram;

[0038] Figure 2 is a GC chromatogram of Example 1;

[0039] Figure 3 is a synthesis route diagram of Example 1;

[0040] Figure 4 is a SEM diagram of polystyrene (a) and a SEM diagram of Example 1 (b);

[0041] Figure 5 is a TEM diagram of Example 1;

[0042] Figure 6 is an XRD diagram of Example 1;

[0043] Figure 7 is an N2-physical adsorption isotherm diagram of Example 1 and Comparative Example 1;

[0044] Figure 8 is a pore size distribution diagram of Example 1 and Comparative Example 1; wherein a is a mesopore distribution diagram, and b is a micropore distribution diagram;

[0045] Figure 9 is a cycle performance diagram of Example 1, Comparative Examples 1 and 2. DETAILED DESCRIPTION

[0046] The experimental methods used in the following examples are conventional methods unless otherwise specified.

[0047] The materials, reagents, etc. used in the following examples can be obtained from commercial channels unless otherwise specified.

[0048] The following embodiments are used to further illustrate the present application, and it should be understood that the following examples are used to better explain the present application, and are not intended to limit the scope of the present application. The above-mentioned catalyst is used for the hydrodeoxygenation reaction of vanillin.

[0049] Sample GC analysis method: the reaction product is analyzed by gas chromatography using Nexis GC-2030; the chromatographic conditions are as follows: the column is a KB-Wax capillary column (30 m x 0.32 mm x 0.50 μm), the carrier gas is N2; the vaporization chamber temperature is 300°C, the detector temperature is 300°C; the temperature program is as follows: 100°C for 3 min, then 10°C / min to 300°C, and finally 300°C for 3 min. The column flow is adjusted to 1 mL / min, the split ratio is 1:50, and the injection volume is 0.2 μL.

[0050] Example 1

[0051] The present embodiment provides a preparation method of a three-dimensional hierarchical ordered mesoporous zeolite confined NiCo alloy catalyst, comprising the following steps:

[0052] (1) 1000 mL of commercially available styrene is mixed with a NaOH solution (0.1 M, 300 mL), stirred vigorously at room temperature, and then the oil and water phases are separated, and the above process is repeated 5 times until the solution is no longer red, to obtain refined styrene;

[0053] (2) 27 mL of the refined styrene prepared in step (1) and 0.24 g of polyvinylpyrrolidone (mw = 55000) are dissolved in 300 mL of deionized water, 25 mL of commercially available styrene is added and continuously stirred, then deoxygenated at 65°C by nitrogen bubbling for 1 h, 10 mL of 0.12 g of potassium persulfate aqueous solution is added to the mixture, and stirred for 24 h, then centrifuged to obtain a polystyrene ball template.

[0054] (3) 7.2 g of tetrapropylammonium hydroxide, 4.6 g of anhydrous ethanol, 5.2 g of tetraethyl orthosilicate, and 8.6 g of deionized water are mixed and stirred at room temperature for 24 h. Then transferred to an autoclave, and hydrothermally treated at 80°C for 72 h to obtain a ZSM-5 seed solution.

[0055] (4) 0.18 g of aluminum nitrate, 3.0 g of tetrapropylammonium hydroxide, 4.6 g of anhydrous ethanol and 8.6 g of deionized water were mixed, and then 5.2 g of tetraethyl orthosilicate and 4.5 mL of ZSM-5 seed solution were sequentially added to the above solution and stirred for 3 h to form a mixed solution.

[0056] (5) 0.2 mL of ethylenediamine (0.003 mol), 0.045 g of Ni(NO3)2·6H2O and 0.045 g of Co(NO3)2·6H2O solution and 0.3 g of polystyrene balls were added to the mixed solution prepared in step (4), and stirred at room temperature for 3 h, and a solid powder was obtained by vacuum evaporation;

[0057] (6) The solid powder of step (5) was transferred to a stainless steel autoclave equipped with a suspended metal mesh, and hydrothermally treated at 80°C for 72 h, cooled, centrifuged, vacuum dried, calcined at 550°C for 6 h, and then reduced at 550°C in a H2 atmosphere for 3 h to obtain a three-dimensionally hierarchical ordered mesoporous zeolite confined NiCo alloy catalyst.

[0058] Catalyst structure characterization: As Figure 4 a, the polystyrene microspheres have an ordered structure and uniform size; Figure 4 b is the structure of the catalyst, which exhibits long-range order and uniform large pore size; Figure 5 is the TEM image of Example 1, and the synthesized catalyst has no obvious large-size aggregated or aggregated NiCo alloy particles, and has high dispersity. Figure 6 is the XRD image of Example 1, and the sample is observed to have an MFI structure, and no diffraction peaks corresponding to Ni and Co are detected, indicating that the NiCo particles are successfully uniformly encapsulated in the ZSM-5 channels. Figure 7 is the N2 adsorption-desorption curve of Example 1, which exhibits type IV isotherm, indicating the presence of mesoporous structure. Figure 8 is the pore size distribution graph of Example 1, confirming that the catalyst has both mesoporous and microporous structures.

[0059] In this example, the catalyst was used in the hydrodeoxygenation reaction of vanillin: 0.12 g of catalyst, 1 mmol of vanillin and 20 mL of deionized water were added to a high-pressure reaction kettle, 2 MPa of H2 was introduced into the reaction kettle, the reaction temperature was 200°C, and the reaction time was 2 h. After the reaction was completed, it was cooled to room temperature, the liquid product was analyzed by gas chromatography, and the conversion rate and selectivity were calculated by quantitative analysis, and the results showed that the conversion rate of vanillin was 100%, and the yield of product 2-methoxy-4-methylphenol was 100%.

[0060] Comparative Example 1

[0061] The difference from Example 1 is only that 3DZSM-5 zeolite is synthesized first, then Ni(NO3)2·6H2O and Co(NO3)2·6H2O solutions are added, which specifically includes the following steps:

[0062] Synthesis of 3DZSM-5: 1000 mL of commercially available styrene was mixed with NaOH solution (0.1 M, 300 mL) under vigorous stirring at room temperature, then the oil and water phases were separated, and the above process was repeated 5 times until the solution was no longer red, obtaining refined styrene. 27 mL of refined styrene and 0.24 g of polyvinylpyrrolidone (mw = 55000) were dissolved in 300 mL of deionized water, 25 mL of commercially available styrene was added and kept stirring, then the mixture was deoxygenated by nitrogen bubbling at 65°C for 1 h, 10 mL of aqueous solution containing 0.12 g of potassium persulfate was added to the mixture, and after stirring for 24 h, polystyrene ball templates were obtained by centrifugation. 7.2 g of tetrapropylammonium hydroxide, 4.6 g of anhydrous ethanol, 5.2 g of tetraethyl orthosilicate and 8.6 g of deionized water were mixed and stirred at room temperature for 24 h. Then it was transferred to an autoclave and hydrothermally treated at 80°C for 72 h to obtain a ZSM-5 seed solution. 0.18 g of aluminum nitrate, 3.0 g of tetrapropylammonium hydroxide, 4.6 g of anhydrous ethanol and 8.6 g of deionized water were mixed, then 5.2 g of tetraethyl orthosilicate and 4.5 mL of ZSM-5 seed solution were added to the above solution in turn and stirred for 3 h to form a mixed solution. 0.2 mL of ethylenediamine and 0.3 g of polystyrene balls were added to the mixed solution, which was stirred at room temperature for 3 h, and a solid powder was obtained by vacuum evaporation; then it was transferred to a stainless steel autoclave and hydrothermally treated at 80°C for 72 h, cooled, centrifuged, vacuum dried, calcined at 550°C for 6 h, and then reduced at 550°C in H2 atmosphere for 3 h to obtain 3DZSM-5 zeolite.

[0063] The NiCo / 3DZSM-5 catalyst was prepared as follows: 0.3 g of 3DZSM-5, 0.2 mL of ethylenediamine, 0.045 g of Ni(NO3)2·6H2O and 0.045 g of Co(NO3)2·6H2O, 50 mL of deionized water were mixed, stirred at room temperature for 12 h, then vacuum dried, calcined at 550°C for 6 h, and then reduced at 550°C in H2 atmosphere for 3 h to obtain the NiCo / 3DZSM-5 catalyst.

[0064] The results show that the conversion rate of vanillin is 93.67%, and the yield of 2-methoxy-4-methylphenol is 72.58%.

[0065] Comparative Example 2

[0066] The difference from Example 1 is that the conventional microporous ZSM-5 zeolite (CZSM-5) is synthesized first, then the solution of Ni(NO3)2·6H2O and Co(NO3)2·6H2O is added, and the conditions of the hydrodeoxygenation of vanillin are the same as those of Example 1.

[0067] Synthesis of conventional microporous ZSM-5 zeolite (CZSM-5): The molar ratio of the initial reaction mixture is 100 SiO2: 1 Al2O3: 5 Na2O: 25 TPAOH: 4000 H2O. Initially, 0.19 g NaOH is stirred with 9.49 g TPAOH and 33.61 g deionized water at room temperature for 30 min. Subsequently, 0.35 g Al(NO3)3·9H2O is added to the mixture and stirring is continued at 60 °C for 1 h. Then 9.72 g TEOS is added to the mixture, which is then stirred at 60 °C for 1 h. The resulting precursor is then transferred to an autoclave and heated in an oven at 180 °C for 48 h. After centrifugation, the solid product is collected and then calcined at 550 °C for 6 h.

[0068] The NiCo / CZSM-5 catalyst is prepared as follows: 0.3 g CZSM-5, 0.2 mL ethylenediamine, 0.045 g Ni(NO3)2·6H2O and 0.045 g Co(NO3)2·6H2O, 50 mL deionized water are mixed, stirred at room temperature for 12 h, vacuum dried, calcined at 550 °C for 6 h, and then reduced at 550 °C in a H2 atmosphere for 3 h to obtain the NiCo / CZSM-5 catalyst.

[0069] The results show that the conversion of vanillin is 43.72%, and the yield of 2-methoxy-4-methylphenol is 43.72%.

[0070] Example 2

[0071] The difference from Example 1 is that ethylenediaminetetraacetic acid is selected instead of ethylenediamine, and the other parameters and conditions are the same as those of Example 1.

[0072] The results show that the conversion of vanillin is 99.98%, and the yield of 2-methoxy-4-methylphenol is 80.11%.

[0073] Example 3

[0074] The difference from Example 1 is that 1,3-propanediaminetetraacetic acid is selected instead of ethylenediamine, and the other parameters and conditions are the same as those of Example 1.

[0075] The results show that the conversion of vanillin is 99.69%, and the yield of 2-methoxy-4-methylphenol is 85.65%.

[0076] Example 4

[0077] The difference from Example 1 is that triethylenediamine is used instead of ethylenediamine, and other parameters and conditions are the same as those in Example 1.

[0078] The results show that the conversion rate of vanillin is 51.48%, and the yield of 2-methoxy-4-methylphenol is 51.48%.

[0079] Example 5

[0080] The difference from Example 1 is that CoCl2·6H2O is used instead of Co(NO3)2·6H2O, and other parameters and conditions are the same as those in Example 1.

[0081] The results show that the conversion rate of vanillin is 100%, and the yield of 2-methoxy-4-methylphenol is 86.17%.

[0082] Example 6

[0083] The difference from Example 1 is that Co(CH3COO)2·4H2O is used instead of Co(NO3)2·6H2O, and other parameters and conditions are the same as those in Example 1.

[0084] The results show that the conversion rate of vanillin is 100%, and the yield of 2-methoxy-4-methylphenol is 94.26%.

[0085] Comparative Example 3

[0086] The difference from Example 1 is that polystyrene sphere template is not added, and other parameters and conditions are the same as those in Example 1.

[0087] The results show that the conversion rate of vanillin is 86.79%, and the yield of 2-methoxy-4-methylphenol is 42.65%.

[0088] Comparative Example 4

[0089] The difference from Example 1 is that Co(NO3)2·6H2O is replaced by Cu(NO3)2·6H2O, and other parameters and conditions are the same as those in Example 1.

[0090] The results show that the conversion rate of vanillin is 100%, and the yield of 2-methoxy-4-methylphenol is 80.92%.

[0091] Comparative Example 5

[0092] The difference from Example 1 is that Co(NO3)2·6H2O is replaced by Zn(NO3)2·6H2O, and other parameters and conditions are the same as those in Example 1.

[0093] The results show that the conversion rate of vanillin is 67.44%, and the yield of 2-methoxy-4-methylphenol is 67.23%.

[0094] Comparative Example 6

[0095] The difference from Example 1 is that Co(NO3)2.6H2O is replaced by Fe(NO3)2.6H2O, and other parameters and conditions are the same as those in Example 1.

[0096] The results show that the conversion rate of vanillin is 71.07%, and the yield of 2-methoxy-4-methylphenol is 70.52%.

[0097] Stability test analysis

[0098] The catalysts in Example 1, Comparative Example 1 and Comparative Example 2 were subjected to a cycle test, and the specific results are shown in Table 2. Figure 9 It can be seen that the confined catalyst has good cycle performance. After 6 cycles, the activity and selectivity of the catalyst do not decrease significantly, the conversion rate of vanillin and the yield of 2-methoxy-4-methylphenol can still reach more than 95% and 90%, respectively, and the catalyst has good stability.

[0099] The examples provided above are not intended to limit the scope covered by the present application, and the described steps are not intended to limit the execution order. Those skilled in the art can make obvious improvements to the present application in combination with existing common knowledge, which also falls within the protection scope defined by the claims of the present application.

Claims

1. A method for preparing a three-dimensional hierarchical ordered mesoporous zeolite-confined NiCo alloy catalyst, characterized in that, Includes the following steps: (1) Mix styrene with NaOH solution, separate the oil and water phases, repeat until the solution no longer appears red, and obtain refined styrene; (2) Dissolve refined styrene and polyvinylpyrrolidone in deionized water, then add styrene and stir continuously, then deoxygenate by bubbling with nitrogen, and finally add potassium persulfate aqueous solution and centrifuge to obtain polystyrene ball template. (3) Mix tetrapropylammonium hydroxide, anhydrous ethanol, tetraethyl orthosilicate and deionized water, transfer to a high-pressure autoclave, and obtain ZSM-5 seed solution after hydrothermal treatment. (4) Mix aluminum nitrate, tetrapropylammonium hydroxide, anhydrous ethanol and deionized water, and then add tetraethyl orthosilicate and ZSM-5 seed solution to form a mixed solution; (5) Add nickel precursor and cobalt precursor solutions coordinated with complexing agent and polystyrene spheres to the mixed solution prepared in step (4), and obtain solid powder by vacuum evaporation; (6) The solid powder from step (5) is transferred to a high-pressure autoclave, hydrothermally treated, cooled, centrifuged, vacuum dried, calcined, and then reduced in H2 atmosphere to obtain a three-dimensional mesoporous zeolite confined NiCo alloy catalyst.

2. The method for preparing the three-dimensional hierarchical ordered mesoporous zeolite confined NiCo alloy catalyst according to claim 1, characterized in that, In step (1), the concentration of the NaOH solution is 0.05 to 0.15 M; the volume ratio of styrene to NaOH solution is 10:2 to 5.

3. The method for preparing the three-dimensional hierarchical ordered mesoporous zeolite confined NiCo alloy catalyst according to claim 1, characterized in that, In step (2), the amounts of refined styrene, polyvinylpyrrolidone, and deionized water are 10-50 mL: 0.1-0.5 g: 200-700 mL; the amounts of polyvinylpyrrolidone and styrene are 0.1-0.5 g: 10-50 mL.

4. The method for preparing the three-dimensional hierarchical ordered mesoporous zeolite confined NiCo alloy catalyst according to claim 1, characterized in that, In step (3), the molar ratio of tetrapropylammonium hydroxide, anhydrous ethanol, and tetraethyl orthosilicate is 0.32–0.37:1:0.25, and the molar ratio of tetraethyl orthosilicate and deionized water is 0.25:4.5–5.0; the hydrothermal treatment temperature is 60–120℃, and the hydrothermal time is 48–120h.

5. The method for preparing the three-dimensional hierarchical ordered mesoporous zeolite confined NiCo alloy catalyst according to claim 1, characterized in that, In step (4), the molar ratio of aluminum nitrate, tetrapropylammonium hydroxide, anhydrous ethanol and deionized water is 0.0048:0.15:1:4.8; the amount of tetraethyl orthosilicate added to ZSM-5 seed solution is 4.5-7.5g:3-7mL; and the molar ratio of tetraethyl orthosilicate to aluminum nitrate is 45-75:

1.

6. The method for preparing the three-dimensional hierarchical ordered mesoporous zeolite confined NiCo alloy catalyst according to claim 1, characterized in that, In step (5), the complexing agent is one of ethylenediamine, ethylenediaminetetraacetic acid, 1,3-propanediaminetetraacetic acid, and triethylenediamine; the nickel precursor is one of Ni(NO3)2·6H2O, NiCl2·6H2O, and Ni(CH3COO)2·4H2O; and the cobalt precursor is one of Co(NO3)2·6H2O, CoCl2·6H2O, and Co(CH3COO)2·4H2O.

7. The method for preparing the three-dimensional hierarchical ordered mesoporous zeolite confined NiCo alloy catalyst according to claim 1, characterized in that, In step (5), the molar ratio of nickel precursor, cobalt precursor and complexing agent is 1:0.5 to 3:

20.

8. The method for preparing the three-dimensional hierarchical ordered mesoporous zeolite confined NiCo alloy catalyst according to claim 1, characterized in that, In step (6), the hydrothermal treatment temperature is 60-120℃ and the hydrothermal time is 48-120h; the calcination temperature is 500-800℃ and the calcination time is 3-8h; the reduction temperature is 400-700℃ and the reduction time is 1-5h.

9. The three-dimensional hierarchical ordered mesoporous zeolite confined NiCo alloy catalyst prepared by the method described in any one of claims 1 to 8.

10. The application of the three-dimensional hierarchical ordered mesoporous zeolite confined NiCo alloy catalyst according to claim 9 in the hydrogenation deoxygenation reaction of vanillin.

Images