Preparation method of defective CoNi-MOF hydrogenation catalyst

Abstract

The invention discloses a preparation method of a defective CoNi-MOF hydrogenation catalyst. The method comprises the following steps: (1) preparing a cobalt-nickel mixed salt ethanol solution; (2) preparing a CoNi-MOF precursor mixed solution; (3) preparation of a bimetallic CoNi-MOF (metal organic framework); (4) preparing a defective CoNi-MOF hydrogenation catalyst; the preparation method has the advantages that 1, by adopting the preparation method, the preparation of the defective CoNi-MOF hydrogenation catalyst is realized; 2, the preparation process is mild in condition, simple and easy to operate; 3, the defective CoNi-MOF catalyst prepared by the method has high activity and good cycling stability when being used for preparing furfuryl alcohol through furfural hydrogenation; and 4, the active site dispersion of the CoNi bimetallic catalyst is controlled by utilizing defects, and the utilization rate of the catalyst is improved and the dosage of the catalyst is reduced through bimetallic concerted catalysis, so that the production cost is reduced, and the method for preparing the catalytic hydrogenation material is expanded.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of hydrogenation catalyst material preparation, and particularly relates to a preparation method of a defective CoNi-MOF hydrogenation catalyst. BACKGROUND

[0002] In the field of catalytic science and material chemistry, metal-organic frameworks (MOFs) have become an ideal precursor material for designing and preparing high-performance catalysts due to their ultra-high specific surface area, adjustable pore structure and rich metal active sites. In particular, bimetallic MOF materials composed of non-noble metals such as cobalt (Co) and nickel (Ni) combine the synergistic electronic effects of the two transition metals and exhibit great potential to replace traditional noble metal (such as Pd, Pt, Ru) catalysts in catalytic hydrogenation reactions, which is of great significance for reducing industrial catalytic costs and promoting the development of green chemistry.

[0003] However, CoNi-MOF catalysts prepared by conventional methods still face several key bottleneck problems when directly used in heterogeneous catalytic hydrogenation reactions, which limits their actual application performance. In the highly ordered MOF crystal structure, metal nodes are usually tightly coordinated by organic ligands, resulting in a limited number of exposed active metal centers with unsaturated coordination sites. This structural characteristic makes it difficult for catalytic substrate molecules to access and effectively adsorb to the active sites, thereby affecting the intrinsic catalytic activity of the hydrogenation reaction; moreover, MOFs materials are usually microporous, and in liquid or gas-liquid-solid heterogeneous hydrogenation reactions, the diffusion of reactant molecules (especially organic macromolecules) to the active sites inside the material and the diffusion of product molecules outward will be significantly hindered, resulting in a large mass transfer resistance, which leads to a decrease in reaction rate and overall catalyst efficiency. At the same time, under harsh catalytic reaction conditions (such as high temperature, high pressure, or specific solvent environment), the metal-ligand bond of the MOF may undergo hydrolysis or rupture, leading to the collapse of the framework structure, the leaching of active components or agglomeration, resulting in catalyst deactivation and affecting its recycling service life.

[0004] In recent years, researchers have found that "defects" in MOFs can improve catalytic performance. Therefore, controllably introducing defect structures is considered as a promising strategy to systematically solve the above problems. By means of metal vacancies, ligand vacancies or introduction of disordered structures, a large number of coordination unsaturated metal sites can be generated in the MOF framework, serving as high-activity catalytic centers. Moreover, defect structures can improve mass transfer efficiency. At the same time, the local electronic environment is changed, the adsorption energy of reactants and the stability of intermediates are optimized, thereby improving the catalytic activity and realizing high efficiency and selectivity of the target unsaturated bond. This structure design enables the CoNi-MOF catalyst to achieve high conversion rate and high selectivity under mild conditions, meeting the requirements of green chemistry for atom economy and resource efficient utilization, and providing a catalytic solution with industrialization potential for the high-value conversion of biomass molecules. SUMMARY

[0005] The purpose of the present application is to provide a preparation method of a defect CoNi-MOF hydrogenation catalyst, solving the problems of low cycle stability and catalytic selectivity of existing catalytic hydrogenation materials. At the same time, the problems of MOF framework structure collapse, metal particle agglomeration and active site reduction, and complex preparation process existing in the preparation of defect MOF catalytic hydrogenation materials in the prior art are solved, thereby improving the catalytic activity.

[0006] To achieve the above purpose, the technical scheme of the present application is a preparation method and application of a CuCo@NC bimetallic catalyst, comprising the following steps: (1) Preparation of cobalt-nickel mixed salt ethanol solution: take a certain mass of cobalt nitrate and nickel acetate in a beaker, add a certain amount of ethanol, ultrasonic for 10 minutes, and uniform stirring for 1 hour to obtain a cobalt-nickel mixed salt ethanol solution; (2) Preparation of CoNi-MOF precursor mixed solution: add a certain mass of 1,3,5-benzenetricarboxylic acid to the solution obtained in step (1), stir for 30 minutes, add a certain amount of N, N-dimethylformamide (DMF), and continue to stir for a period of time to obtain a CoNi-MOF precursor mixed solution; (3) Preparation of bimetallic CoNi-MOF: put the CoNi-MOF precursor mixed solution obtained in step (2) into an autoclave, heat in a forced air drying oven at constant temperature for 4-6 h, cool to room temperature, centrifuge the obtained product, wash with water and ethanol in turn, and dry at 80℃ for 12 h to obtain bimetallic CoNi-MOF; (4) Preparation of defect CoNi-MOF hydrogenation catalyst: put the bimetallic CoNi-MOF obtained in step (3) into a tube furnace, control the temperature and vacuum calcine for 2-4 h, wherein the heating rate is 2℃ / min, cool and grind to obtain a defect Co-MOF derivative catalyst.

[0007] The step (one) is that the volume of ethanol is 50-100 mL, the mass ratio of cobalt nitrate and nickel acetate is 3:1-5:1.

[0008] The step (two) is that the mass of 1,3,5-benzene tricarboxylic acid is 1.5-2.5 g, the volume of N, N-dimethylformamide (DMF) is 50-100 mL, and the stirring time is 1-3 hours.

[0009] The step (three) is that the temperature of the air blowing drying box is controlled to be 110-140 DEG C, and the heating time is 4-6 h.

[0010] The step (four) is that the temperature is controlled to be 200-450 DEG C, the vacuum degree is-0.05-0.08 MPa, and the calcination time is 2-4 h.

[0011] The ultrasonic power is 150 W.

[0012] The advantages of the present application are: one, the preparation method is adopted to realize the preparation of the defective CoNi-MOF hydrogenation catalyst; two, the preparation process condition is mild, simple and easy to operate; three, the defective CoNi-MOF catalyst prepared by the present application has high activity for the preparation of furfuryl alcohol by hydrogenation of furfural and good cycle stability; four, the present application realizes the dispersion of the active sites of the CoNi bimetallic catalyst by defect control, improves the utilization rate through bimetallic synergistic catalysis, reduces the catalyst consumption, and further reduces the production cost, and expands the method for preparing catalytic hydrogenation materials. BRIEF DESCRIPTION OF DRAWINGS

[0013] Figure 1 It is the scanning electron microscope graph of the obtained defective CoNi-MOF hydrogenation catalyst. DETAILED DESCRIPTION

[0014] In order to better understand the present application, the technical scheme of the present application is illustrated by specific examples as follows.

[0015] Example 1: a preparation method of a defective CoNi-MOF hydrogenation catalyst, which is completed according to the following steps: (one) preparation of cobalt-nickel mixed salt ethanol solution: 2.4 g of cobalt nitrate and 0.8 g of nickel acetate are taken in a beaker, 50 mL of ethanol is added, ultrasonic is performed for 10 minutes, and uniform stirring is performed for 1 hour to obtain a cobalt-nickel mixed salt ethanol solution; (two) preparation of CoNi-MOF precursor mixed solution: 1.5 g of 1,3,5-benzene tricarboxylic acid is added to the mixed solution obtained in the step (one), stirring is performed for 30 minutes, 50 mL of N, N-dimethylformamide (DMF) is added, and stirring time is 3 hours to obtain a CoNi-MOF precursor mixed solution; (Three) Preparation of bimetallic CoNi-MOF: Put the CoNi-MOF precursor mixed solution obtained in step (two) into a hydrothermal kettle, place it in a forced air drying oven at 110°C for 6 hours, cool to room temperature, centrifuge the obtained product, wash with water and ethanol in turn, and dry at 80°C for 12 hours to obtain bimetallic CoNi-MOF; (Four) Preparation of defect CoNi-MOF hydrogenation catalyst: Put the bimetallic CoNi-MOF obtained in step (three) into a tube furnace, control the vacuum degree to be-0.05 MPa, control the temperature to be 200°C, and calcine for 4 hours, wherein the temperature rising rate is 2°C / min, cool and grind to obtain a defect Co-MOF derivative catalyst; The ultrasonic power is 150 W.

[0016] Example 2: A preparation method of a defect CoNi-MOF hydrogenation catalyst, which is completed according to the following steps: (One) Preparation of cobalt-nickel mixed salt ethanol solution: Take 2.7 g and 0.9 g of cobalt nitrate and nickel acetate respectively into a beaker, add 80 mL of ethanol, ultrasonic for 10 minutes, and uniform speed stirring for 1 hour to obtain a cobalt-nickel mixed salt ethanol solution; (Two) Preparation of CoNi-MOF precursor mixed solution: Add 2.0 g of 1,3,5-benzenetricarboxylic acid to the mixed solution obtained in step (one), stir for 30 minutes, add 80 mL of N, N-dimethylformamide (DMF), and stir for 2 hours to obtain a CoNi-MOF precursor mixed solution; (Three) Preparation of bimetallic CoNi-MOF: Put the CoNi-MOF precursor mixed solution obtained in step (two) into a hydrothermal kettle, place it in a forced air drying oven at 120°C for 5 hours, cool to room temperature, centrifuge the obtained product, wash with water and ethanol in turn, and dry at 80°C for 12 hours to obtain bimetallic CoNi-MOF; (Four) Preparation of defect CoNi-MOF hydrogenation catalyst: Put the bimetallic CoNi-MOF obtained in step (three) into a tube furnace, control the vacuum degree to be-0.07 MPa, control the temperature to be 300°C, and calcine for 3 hours, wherein the temperature rising rate is 2°C / min, cool and grind to obtain a defect Co-MOF derivative catalyst; The ultrasonic power is 150 W.

[0017] Example 3: A preparation method of a defect CoNi-MOF hydrogenation catalyst, which is completed according to the following steps: (One) Preparation of cobalt-nickel mixed salt ethanol solution: Take 3.0 g and 1.0 g of cobalt nitrate and nickel acetate respectively into a beaker, add 100 mL of ethanol, ultrasonic for 10 minutes, and uniform speed stirring for 1 hour to obtain a cobalt-nickel mixed salt ethanol solution; (ii) Preparation of CoNi-MOF precursor mixed solution: 2.5 g of 1,3,5-benzenetricarboxylic acid was added to the mixed solution obtained in step (i), stirred for 30 minutes, 100 mL of N, N-dimethylformamide (DMF) was added, and stirred for 1 hour to obtain a CoNi-MOF precursor mixed solution; (iii) Preparation of bimetallic CoNi-MOF: The CoNi-MOF precursor mixed solution obtained in step (ii) was placed in a hydrothermal kettle, heated at 140°C in a forced air drying oven for 4 h, and then cooled to room temperature. The obtained product was centrifuged, washed with water and ethanol in sequence, and dried at 80°C for 12 h to obtain bimetallic CoNi-MOF; (iv) Preparation of defect CoNi-MOF hydrogenation catalyst: The bimetallic CoNi-MOF obtained in step (iii) was placed in a tube furnace, the vacuum degree was -0.08 MPa, the temperature was controlled at 450°C, and the heating rate was 2°C / min for 2 h. After cooling and grinding, a defect Co-MOF derivative catalyst was obtained; The ultrasonic power is 150 W.

Claims

1. A method for preparing a defective CoNi-MOF hydrogenation catalyst, characterized in that: The preparation method includes the following steps: (a) Preparation of cobalt-nickel mixed salt ethanol solution: Take a certain mass of cobalt nitrate and nickel acetate into a beaker, add a certain amount of ethanol, sonicate for 10 minutes, and stir at a constant speed for 1 hour to obtain cobalt-nickel mixed salt ethanol solution; (II) Preparation of CoNi-MOF precursor mixture: Add a certain mass of 1,3,5-benzenetricarboxylic acid to the solution obtained in step (I), stir for 30 minutes, add a certain amount of N,N-dimethylformamide (DMF), and continue stirring for a period of time to obtain CoNi-MOF precursor mixture; (III) Preparation of bimetallic CoNi-MOF: The CoNi-MOF precursor mixture obtained in step (II) was placed in a hydrothermal reactor and heated at a constant temperature in a forced-air drying oven for 4-6 h. After cooling to room temperature, the product was centrifuged, washed with water and ethanol in sequence, and dried at 80℃ for 12 h to obtain bimetallic CoNi-MOF. (iv) Preparation of defective CoNi-MOF hydrogenation catalyst: The bimetallic CoNi-MOF obtained in step (iii) is placed in a tube furnace and calcined under vacuum for 2 to 4 h with a heating rate of 2 °C / min. After cooling and grinding, the defective Co-MOF derivative catalyst is obtained.

2. The method for preparing a defective CoNi-MOF hydrogenation catalyst according to claim 1, characterized in that: In step (a), the volume of ethanol is 50-100 mL, and the mass ratio of cobalt nitrate to nickel acetate is 3:1-5:

1.

3. The method for preparing a defective CoNi-MOF hydrogenation catalyst according to claim 1, characterized in that: In step (ii), the mass of 1,3,5-benzenetricarboxylic acid added is 1.5–2.5 g, the volume of N,N-dimethylformamide (DMF) is 50–100 mL, and the stirring time is 1–3 hours.

4. The method for preparing a defective CoNi-MOF hydrogenation catalyst according to claim 1, characterized in that: The temperature of the forced-air drying oven in step (iii) is controlled at 110-140℃, and the heating time is 4-6 hours.

5. The method for preparing a defective CoNi-MOF hydrogenation catalyst according to claim 1, characterized in that: In step (iv), the temperature is controlled at 200–450°C, the vacuum degree is -0.05–0.08 MPa, and the calcination time is 2–4 h.

6. The method for preparing a defective CoNi-MOF hydrogenation catalyst according to claim 1, characterized in that: The ultrasonic power is 150 W.

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