MOF-derived catalyst, preparation method and application of MOF-derived catalyst in catalyzing hydrogen storage and hydrogen release of hydrogen storage system

Abstract

The invention discloses an MOF-derived catalyst, a preparation method and application of the MOF-derived catalyst in catalyzing hydrogen storage and hydrogen release of a hydrogen storage system, and belongs to the technical field of hydrogen storage. The catalyst is a derivative of a copper-based metal organic framework compound (Cu-MOF), the Cu-MOF is prepared from a copper salt, a ligand and a solvent under the heating condition, or the Cu-MOF is prepared from the copper salt, the ligand and the solvent under the heating condition, then the metal salt of an auxiliary agent is loaded on the Cu-MOF, and finally the catalyst is obtained after roasting in inert gas and reduction. The catalyst provided by the invention can maintain the skeleton structure of MOF, has a relatively high specific surface area, is easy to produce carbon-coated Cu particles, can limit the growth of the Cu particles, and improves the stability of the catalyst. The raw materials copper salt, terephthalic acid, formic acid and acetic acid of the catalyst are easy to obtain and low in price, the price of the catalyst can be effectively reduced, and industrial application is easy to achieve.

Description

Technical Field

[0001] The present invention belongs to the technical field of hydrogen storage, and more specifically, relates to a MOF-derived catalyst, a preparation method thereof, and an application thereof in catalyzing hydrogen storage and hydrogen release in a 1,4-butanediol / γ-butyrolactone hydrogen storage system. Background Art

[0002] In recent years, due to energy shortages and environmental pollution problems, clean, green, low-carbon, and sustainable new energy sources have attracted much attention. Hydrogen energy has become one of the most promising clean alternative energy sources due to its pollution-free, high energy, and wide sources. The storage and transportation of hydrogen are the difficulties in the development of the hydrogen energy industry. Common hydrogen storage and transportation methods include high-pressure gaseous hydrogen storage, cryogenic liquid hydrogen storage, etc. High-pressure gaseous hydrogen storage has problems such as low hydrogen storage density and poor safety. Liquid hydrogen storage liquefies hydrogen at low temperatures. Although liquid hydrogen has a high energy density, the liquefaction process consumes a large amount of energy and has high requirements for hydrogen storage tanks.

[0003] The above methods are not suitable for large-scale hydrogen transportation due to high costs. The liquid organic hydrogen carriers (LOHCs) technology can solve the problem of difficult large-scale long-distance hydrogen transportation. Currently, liquid organic hydrogen storage mainly includes some unsaturated organic aromatic hydrocarbons and heterocyclic molecules. Unsaturated organic aromatic hydrocarbons are relatively stable but have disadvantages such as high hydrogenation and dehydrogenation temperatures. Compared with unsaturated organic aromatic hydrocarbons, heterocyclic molecules have milder hydrogenation and dehydrogenation conditions, lower hydrogenation and dehydrogenation temperatures, and higher hydrogen storage capacities, but most of them have disadvantages such as high melting points, which greatly limit their applications.

[0004] 1,4-Butanediol is a bulk organic chemical with a production capacity of over 6 million tons in 2024. The theoretically releasable hydrogen amount is 4.4 wt%, and it can be used as a hydrogen storage material. Chinese invention patent CN115414934B discloses a solid copper-based catalyst with a copper silicate malachite and / or atacamite crystal structure as a precursor and its application in a 1,4-butanediol / γ-butyrolactone hydrogen storage system. However, the catalyst synthesis process is relatively complex and not conducive to large-scale production. Summary of the Invention

[0005] In view of the above-mentioned disadvantages of the prior art, the purpose of the present invention is to provide a copper-based metal-organic framework compound (Cu-MOF)-derived catalyst with a simple synthesis process, a preparation method thereof, and an application thereof in catalyzing hydrogen storage and hydrogen release in a 1,4-butanediol / γ-butyrolactone hydrogen storage system.

[0006] To achieve the above purpose, the present invention provides the following technical solutions:

[0007] In the first aspect, the present invention provides a method for preparing a copper-based metal-organic framework compound (Cu-MOF) derived catalyst, comprising the following steps:

[0008] (1) Heat copper salt, ligand, and solvent at 40 - 120 °C to prepare Cu-MOF;

[0009] Alternatively, heat copper salt, ligand, and solvent at 40 - 120 °C to prepare Cu-MOF, and then load the metal salt of the promoter onto Cu-MOF;

[0010] (2) Calcinate the material obtained in step (1) in an inert gas at 400 - 800 °C, and then reduce it in hydrogen gas to obtain the catalyst.

[0011] Based on the above technical solution, further, the copper salt in step (1) is one of copper nitrate, copper sulfate, copper chloride, and copper acetate, the ligand is at least one of terephthalic acid, trimesic acid, acetic acid, and formic acid, and the solvent is one of methanol, ethanol, propanol, dimethylformamide, and dimethylacetamide.

[0012] Based on the above technical solution, further, the heating temperature in step (1) is controlled at 60 - 120 °C, and the heating time is controlled at 10 - 30 h.

[0013] Based on the above technical solution, further, the initial concentration of the copper salt in the mixed solution in step (1) is 1 - 10 mol / L.

[0014] Based on the above technical solution, further, the molar ratio of the copper salt to the ligand in step (1) is 1:0.1 - 1:1, preferably 1:0.5 - 1:1.

[0015] Based on the above technical solution, further, the promoter in step (1) is one of Fe, Ce, Zn, Zr, Al, Mn, Ni, La, In, Sn, and Ga, and the metal salt of the promoter is one of the nitrate, sulfate, acetate, and chloride of the promoter.

[0016] Based on the above technical solution, further, the content of the promoter in step (1) is 0.01 - 5 wt% of the mass of Cu-MOF.

[0017] Based on the above technical solution, further, in step (1), the metal salt of the promoter is loaded onto Cu-MOF by the equal-volume impregnation method.

[0018] Based on the above technical solution, further, the inert gas in step (2) is one of nitrogen, argon, neon, and helium, the calcination temperature is 400 - 600 °C, and the reduction temperature is 200 - 400 °C, preferably 230 - 350 °C.

[0019] In a second aspect, the present invention provides a copper-based metal-organic framework compound-derived catalyst prepared by the above preparation method.

[0020] In a third aspect, the present invention provides the application of the above copper-based metal-organic framework compound-derived catalyst in hydrogen storage and hydrogen release in a catalytic hydrogen storage system, and the hydrogen storage system includes a hydrogen-rich component 1,4-butanediol and a hydrogen-poor component γ-butyrolactone.

[0021] Based on the above technical solution, further, the reaction conditions for hydrogen release are: the reaction temperature is 100 - 220 °C, preferably 150 - 200 °C, the reaction pressure is 0.01 - 0.5 MPa, preferably 0.1 - 0.4 MPa, and the mass ratio of the catalyst to the hydrogen storage system is 1:5 - 1:100.

[0022] Based on the above technical solution, further, the reaction conditions for hydrogen storage are: the reaction temperature is 150 - 250 °C, preferably 180 - 220 °C, the reaction pressure is 1 - 6 MPa, preferably 2 - 5 MPa, and the mass ratio of the catalyst to the hydrogen storage system is 1:5 - 1:100.

[0023] The present invention has the following beneficial effects:

[0024] 1) The Cu-MOF-derived catalyst can maintain the framework structure of MOF, has a high specific surface area, and the Cu particles obtained by heat treatment have high dispersibility and small particle size, which is beneficial to improving the activity of the catalyst.

[0025] 2) The raw materials used for preparing Cu-MOF, namely copper salt, terephthalic acid, formic acid, and acetic acid, are easily available and inexpensive, which can effectively reduce the price of the catalyst.

[0026] 3) Adding a small amount of acetic acid or formic acid to the ligand can increase the defects of Cu-MOF, increase the specific surface area of Cu-MOF, and is more conducive to the dispersion of Cu particles.

[0027] 4) The derivative of Cu-MOF obtained by calcination in an inert atmosphere can obtain a structure of carbon material-coated Cu particles, which is beneficial to improving the stability of the catalyst in liquid-phase reactions. Description of the Drawings

[0028] In order to more clearly illustrate the embodiments of the present invention, the drawings related to the embodiments will be briefly introduced below.

[0029] Figure 1 Test results of dehydrogenation-hydrogenation cycle for the catalyst in Example 3. Detailed implementation manners

[0030] The present invention will be described in detail below in conjunction with embodiments. However, the implementation manners of the present invention are not limited thereto. Obviously, the embodiments described below are only partial embodiments of the present invention. For those skilled in the art, without creative efforts, obtaining other similar embodiments will fall within the protection scope of the present invention.

[0031] In the embodiments, an Agilent 7890B high-performance gas chromatograph was used to analyze the products in the reaction, and the external standard method was used for quantification. The test conditions in the embodiments were as follows: the chromatographic column was FFAP, the hydrogen flame detector (FID), hydrogen was used as the carrier gas, the constant mode, the split ratio was 100:1, the column oven temperature was 70 °C (2 min), and it was raised to 270 °C at 30 °C / min (held for 2 min).

[0032] Example 1

[0033] A solution containing copper nitrate trihydrate (0.1 mol), terephthalic acid (0.075 mol), and dimethylformamide (20 mL) was heated at 100 °C for 24 hours, filtered, and washed to obtain MOF. The MOF was heated at 500 °C for 5 hours in a nitrogen atmosphere and then reduced at 300 °C for 2 h to obtain the catalyst.

[0034] Catalytic dehydrogenation reaction in a batch autoclave reactor: 1,4-butanediol (10 g) and the catalyst (1 g) were added to a 25 mL polytetrafluoroethylene inner liner. A batch autoclave equipped with a back pressure valve was used to maintain the pressure in the autoclave at 0.2 MPa. 0.2 MPa of nitrogen was charged before the reaction, and it was heated to 190 °C and reacted for 6 hours. The liquid-phase product and the gas-phase product were collected and analyzed by FID and TCD gas chromatography respectively. After calculation, the conversion rate of 1,4-butanediol was 56.2%, the selectivity of γ-butyrolactone was 98.3%, and the hydrogen purity was 95.5%.

[0035] Catalytic hydrogenation reaction in a batch autoclave reactor: γ-butyrolactone (10 g) and the catalyst (1 g) were added to a 25 mL polytetrafluoroethylene inner liner. A batch autoclave equipped with a back pressure valve was used to maintain the pressure in the autoclave at 5 MPa. 5 MPa of hydrogen was charged before the reaction, the hydrogenation reaction temperature was 200 °C, and the reaction was carried out for 6 hours. The liquid-phase product was collected and analyzed by gas chromatography. After calculation, the conversion rate of γ-butyrolactone was 89.9%, and the selectivity of 1,4-butanediol was 95.6%.

[0036] Example 2

[0037] A solution containing copper nitrate trihydrate (0.1 mol), terephthalic acid (0.065 mol), acetic acid (0.01 mol), and dimethylformamide (20 mL) was heated at 100 °C for 24 hours, filtered, and washed to obtain MOF. The MOF was heated at 500 °C for 5 hours in a nitrogen atmosphere and then reduced at 300 °C for 2 h to obtain the catalyst.

[0038] Catalytic dehydrogenation reaction in a batch autoclave reactor: 1,4-butanediol (10 g) and the catalyst (1 g) were added to a 25 mL polytetrafluoroethylene liner. A batch autoclave equipped with a backpressure valve was used to maintain the pressure in the autoclave at 0.2 MPa. Before the reaction, 0.2 MPa of nitrogen was introduced, and the temperature was raised to 190 °C. The reaction was carried out for 6 hours. The liquid and gas phase products were collected and analyzed by FID and TCD gas chromatography, respectively. The conversion of 1,4-butanediol was calculated to be 62.6%, the selectivity to γ-butyrolactone was 99.5%, and the hydrogen purity was 97.6%.

[0039] Catalytic hydrogenation reaction in a batch autoclave reactor: γ-butyrolactone (10 g) and the catalyst (1 g) were added to a 25 mL polytetrafluoroethylene liner. A batch autoclave equipped with a backpressure valve was used to maintain the pressure in the autoclave at 5 MPa. Before the reaction, 5 MPa of hydrogen was introduced, and the hydrogenation reaction temperature was 200 °C. The reaction was carried out for 6 hours. The liquid phase product was collected and analyzed by gas chromatography. The conversion of γ-butyrolactone was calculated to be 90.2%, and the selectivity to 1,4-butanediol was 96.0%.

[0040] Example 3

[0041] A solution containing copper nitrate trihydrate (0.1 mol), terephthalic acid (0.065 mol), acetic acid (0.01 mol), and dimethylformamide (20 mL) was heated at 100 °C for 24 hours, filtered, and washed to obtain MOF. An aqueous solution of zinc nitrate containing 20 mg of zinc was impregnated onto the MOF (1 g) in an equal volume, dried, heated at 500 °C for 5 hours in a nitrogen atmosphere, and then reduced at 300 °C for 2 h to obtain the catalyst.

[0042] Catalytic dehydrogenation reaction in a batch autoclave reactor: 1,4-butanediol (10 g) and the catalyst (1 g) were added to a 25 mL polytetrafluoroethylene liner. A batch autoclave equipped with a backpressure valve was used to maintain the pressure in the autoclave at 0.2 MPa. Before the reaction, 0.2 MPa of nitrogen was introduced, and the temperature was raised to 190 °C. The reaction was carried out for 6 hours. The liquid and gas phase products were collected and analyzed by FID and TCD gas chromatography, respectively. The conversion of 1,4-butanediol was calculated to be 96.4%, the selectivity to γ-butyrolactone was 99.7%, and the hydrogen purity > 99.9%.

[0043] Catalytic hydrogenation reaction in a batch reactor: Add γ-butyrolactone (10 g) and a catalyst (1 g) into a 25 mL polytetrafluoroethylene liner. Use a batch reactor equipped with a back pressure valve to maintain the pressure in the reactor at 5 MPa. Charge 5 MPa of hydrogen before the reaction. The hydrogenation reaction temperature is 200 °C, and the reaction lasts for 6 hours. Collect the liquid-phase product and analyze it using gas chromatography. After calculation, the conversion rate of γ-butyrolactone is 93.5%, and the selectivity of 1,4-butanediol is 99.6%.

[0044] Example 4

[0045] A solution containing copper nitrate trihydrate (0.1 mol), terephthalic acid (0.065 mol), acetic acid (0.01 mol), and dimethylformamide (20 mL) is heated at 100 °C for 24 hours, filtered, and washed to obtain MOF. An aqueous solution of nickel nitrate containing 20 mg of nickel is impregnated onto MOF (1 g) in an equal volume. After drying, it is heated at 500 °C for 5 hours in a nitrogen atmosphere and then reduced at 300 °C for 2 h to obtain the catalyst.

[0046] Catalytic dehydrogenation reaction in a batch reactor: Add 1,4-butanediol (10 g) and a catalyst (1 g) into a 25 mL polytetrafluoroethylene liner. Use a batch reactor equipped with a back pressure valve to maintain the pressure in the reactor at 0.2 MPa. Charge 0.2 MPa of nitrogen before the reaction, heat to 190 °C, and react for 6 hours. Collect the liquid-phase product and the gas-phase product and analyze them using FID and TCD gas chromatography respectively. After calculation, the conversion rate of 1,4-butanediol is 89.3%, the selectivity of γ-butyrolactone is 90.0%, and the hydrogen purity is 92.3%.

[0047] Catalytic hydrogenation reaction in a batch reactor: Add γ-butyrolactone (10 g) and a catalyst (1 g) into a 25 mL polytetrafluoroethylene liner. Use a batch reactor equipped with a back pressure valve to maintain the pressure in the reactor at 5 MPa. Charge 5 MPa of hydrogen before the reaction. The hydrogenation reaction temperature is 200 °C, and the reaction lasts for 6 hours. Collect the liquid-phase product and analyze it using gas chromatography. After calculation, the conversion rate of γ-butyrolactone is 81.1%, and the selectivity of 1,4-butanediol is 92.3%.

[0048] Example 5

[0049] A solution containing copper nitrate trihydrate (0.1 mol), terephthalic acid (0.075 mol), and dimethylformamide (20 mL) is heated at 100 °C for 24 hours, filtered, and washed to obtain MOF. MOF is heated at 800 °C for 5 hours in a nitrogen atmosphere and then reduced at 300 °C for 2 h to obtain the catalyst.

[0050] Catalytic dehydrogenation reaction in a batch autoclave reactor: 1,4-butanediol (10 g) and a catalyst (1 g) were added to a 25 mL polytetrafluoroethylene inner lining. A batch autoclave equipped with a back-pressure valve was used to maintain the pressure inside the autoclave at 0.2 MPa. Before the reaction, 0.2 MPa of nitrogen was charged, and the mixture was heated to 190 °C and reacted for 6 hours. The liquid and gas products were collected and analyzed by FID and TCD gas chromatography, respectively. The calculated conversion rate of 1,4-butanediol was 43.6%, the selectivity of γ-butyrolactone was 86.8%, and the purity of hydrogen was 95.0%.

[0051] Catalytic hydrogenation reaction in a batch autoclave reactor: γ-butyrolactone (10 g) and a catalyst (1 g) were added to a 25 mL polytetrafluoroethylene inner lining. A batch autoclave equipped with a back-pressure valve was used to maintain the pressure inside the autoclave at 5 MPa. Before the reaction, 5 MPa of hydrogen was charged, the hydrogenation reaction temperature was 200 °C, and the reaction was carried out for 6 hours. The liquid product was collected and analyzed by gas chromatography. The calculated conversion rate of γ-butyrolactone was 52.8%, and the selectivity of 1,4-butanediol was 83.1%.

[0052] Example 6

[0053] A solution containing copper nitrate trihydrate (0.1 mol), terephthalic acid (0.075 mol), and dimethylformamide (20 mL) was heated at 100 °C for 24 hours, filtered, and washed to obtain MOF. The MOF was heated at 500 °C for 5 hours in an air atmosphere and then reduced at 300 °C for 2 h to obtain the catalyst.

[0054] Catalytic dehydrogenation reaction in a batch autoclave reactor: 1,4-butanediol (10 g) and a catalyst (1 g) were added to a 25 mL polytetrafluoroethylene inner lining. A batch autoclave equipped with a back-pressure valve was used to maintain the pressure inside the autoclave at 0.2 MPa. Before the reaction, 0.2 MPa of nitrogen was charged, and the mixture was heated to 190 °C and reacted for 6 hours. The liquid and gas products were collected and analyzed by FID and TCD gas chromatography, respectively. The calculated conversion rate of 1,4-butanediol was: 12.1%, the selectivity of γ-butyrolactone was 45.2%, and the purity of hydrogen was 68.1%.

[0055] Catalytic hydrogenation reaction in a batch autoclave reactor: γ-butyrolactone (10 g) and a catalyst (1 g) were added to a 25 mL polytetrafluoroethylene inner lining. A batch autoclave equipped with a back-pressure valve was used to maintain the pressure inside the autoclave at 5 MPa. Before the reaction, 5 MPa of hydrogen was charged, the hydrogenation reaction temperature was 200 °C, and the reaction was carried out for 6 hours. The liquid product was collected and analyzed by gas chromatography. The calculated conversion rate of γ-butyrolactone was 15.4%, and the selectivity of 1,4-butanediol was 52.0%.

[0056] Example 7

[0057] The dehydrogenation and hydrogenation cyclicity tests were carried out using the catalyst in Example 3. The specific process was as follows:

[0058] Add 1,4-butanediol (10 g) and a catalyst (1 g) into a 25 mL polytetrafluoroethylene-lined reactor. Use a batch reactor equipped with a back pressure valve to maintain the pressure in the reactor at 0.2 MPa. Charge 0.2 MPa of nitrogen before the reaction, heat to 190 °C, and react for 10 hours. After cooling to room temperature, use FID and TCD gas chromatography to analyze the liquid-phase product (0.1 mL) and the gas-phase product respectively. Charge 5 MPa of hydrogen into the reactor, set the hydrogenation reaction temperature at 200 °C, and react for 10 hours. After cooling to room temperature, release the hydrogen pressure, and use gas chromatography to analyze the liquid-phase product (0.1 mL). Then continue dehydrogenation and hydrogenation. The data for 10 cycles are shown in Figure 1 . The purity of the hydrogen generated during all dehydrogenation processes is maintained at >99.9%.

[0059] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the present invention, not to limit them; although the present invention has been described in detail with reference to the foregoing examples, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing examples, or perform equivalent replacements for some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the various examples of the present invention.

Claims

1. A preparation method of a copper-based metal-organic framework compound (Cu-MOF) derived catalyst, characterized in that, It includes the following steps: (1) Heat copper salt, ligand, and solvent at 40 - 120 °C to prepare Cu-MOF; Alternatively, heat copper salt, ligand, and solvent at 40 - 120 °C to prepare Cu-MOF, and then load the metal salt of the promoter onto Cu-MOF; (2) Calcinate the material obtained in step (1) in an inert gas at 400 - 800 °C, and then reduce it in hydrogen gas to obtain the catalyst.

2. The preparation method according to claim 1, characterized in that, In step (1), the copper salt is one of copper nitrate, copper sulfate, copper chloride, and copper acetate, the ligand is at least one of terephthalic acid, trimellitic acid, acetic acid, and formic acid, and the solvent is one of methanol, ethanol, propanol, dimethylformamide, and dimethylacetamide; the heating temperature is controlled at 60 - 120 °C, and the heating time is controlled at 10 - 30 h.

3. The preparation method according to claim 1, wherein In step (1), the initial concentration of copper salt in the mixed solution is 1 - 10 mol / L, and the molar ratio of the copper salt to the ligand is 1:0.1 - 1:1, preferably 1:0.5 - 1:

1.

4. The preparation method according to claim 1, characterized in that In step (1), the promoter is one of Fe, Ce, Zn, Zr, Al, Mn, Ni, La, In, and Sn, and the metal salt of the promoter is one of the nitrate, sulfate, acetate, and chloride of the promoter; the content of the promoter is 0.01 - 5 wt% of the mass of Cu-MOF.

5. The preparation method according to claim 1, characterized in that, In step (1), the metal salt of the promoter is loaded onto Cu-MOF by the equal-volume impregnation method.

6. The preparation method according to claim 1, characterized in that, In step (2), the inert gas is one of nitrogen, argon, neon, and helium, the calcination temperature is 400 - 600 °C, and the reduction temperature is 200 - 400 °C, preferably 230 - 350 °C.

7. A copper-based metal-organic framework compound-derived catalyst prepared by the preparation method according to any one of claims 1 - 6.

8. Use of the copper-based metal-organic framework compound-derived catalyst according to claim 7 in catalyzing hydrogen storage and hydrogen release in a hydrogen storage system, characterized in that, The hydrogen storage system includes the hydrogen-rich component 1,4-butanediol and the hydrogen-poor component γ-butyrolactone.

9. The application according to claim 8, wherein, The reaction conditions for hydrogen release are: the reaction temperature is 100 - 220 °C, preferably 150 - 200 °C, the reaction pressure is 0.01 - 0.5 MPa, preferably 0.1 - 0.4 MPa, and the mass ratio of the catalyst to the hydrogen storage system is 1:5 - 1:

100.

10. The application according to claim 8, wherein The reaction conditions for hydrogen storage are: the reaction temperature is 150 - 250 °C, preferably 180 - 220 °C, the reaction pressure is 1 - 6 MPa, preferably 2 - 5 MPa, and the mass ratio of the catalyst to the hydrogen storage system is 1:5 - 1:100.

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