METHOD FOR PREPARING PT-BASED ALLOY / MOFS CATALYST WITH HIGH HYDROGENATION SELECTIVITY AND APPLICATION THEREOF

Abstract

The present disclosure relates to the technical field of molecular biology, and in particular to a method for preparing a Pt-based alloy/MOFs catalyst with high hydrogenation selectivity, and a preparation method thereof. The present disclosure prepares a Pt-based alloy/MOFs structure with Pt alloy particles uniformly supported on the surface of MOFs in one step through a simple solvothermal method, the preparation method of the present disclosure is simple, the reaction environment is not harsh and does not require a special atmosphere. The resulting product has a unique structure, with small metal particles, uniform distribution and not easy to lose, and it will not affect the catalytic activity of the metal. In terms of catalytic performance, the obtained Pt alloy/MOFs catalyst can catalytically hydrogenate cinnamaldehyde under normal temperature and pressure, and has excellent performance. In addition, the catalyst can also catalyze the selective hydrogenation of 3-nitrostyrene, catalyze the dehydrogenation of tetrahydroquinoline, which proves that the catalyst of the present disclosure has a wide range of applications.

Claims

1. A method for preparing a Pt-based alloy/MOFs catalyst, wherein comprising the following steps: adding a MOFs carrier to DMF, dispersing and stirring at room temperature, then adding platinum acetylacetonate and terephthalic acid, continuing to stir at room temperature, adding a certain amount of acetylacetone metal salt, then stirring at room temperature, placing the resulting solution at 140-160? C. for continuous stirring for 10-15 h, and then performing centrifugation, washing and drying to obtain the Pt-based alloy/MOFs catalyst.

2. The method according to claim 1, wherein the MOFs carrier includes UiO-66-NH.sub.2, UiO-66 or MIL-101(Cr).

3. The method according to claim 2, wherein the method for preparing UiO-66-NH.sub.2 is as follows: adding zirconium tetrachloride and 2-aminoterephthalic acid to DMF, then adding acetic acid, stirring at room temperature, then reacting under high temperature of 110-130? C. and high pressure for 10-15 h, and finally performing centrifugation, washing and drying to obtain the UiO-66-NH.sub.2.

4. The method according to claim 3, wherein in the preparation process of UiO-66-NH.sub.2, the solid-to-liquid ratio of terephthalic acid to DMF is 36 mg/50 mL.

5. The method according to claim 3, wherein in the preparation process of UiO-66-NH.sub.2, the solid-to-liquid ratio of zirconium tetrachloride to DMF is 52 mg/50 mL.

6. The method according to claim 3, wherein in the preparation process of UiO-66-NH.sub.2, the volume ratio of acetic acid to DMF is 3:25.

7. The method according to claim 3, wherein in the preparation process of UiO-66-NH.sub.2, the washing is washing twice with DMF and ethanol respectively; and the drying is vacuum drying at 120? C.

8. The method according to claim 1, wherein the acetylacetone metal salt includes ferrous acetylacetonate, nickel acetylacetonate, or cobalt acetylacetonate.

9. The method according to claim 1, wherein the solid-to-liquid ratio of the MOFs carrier to DMF is (40-60) mg/5 mL.

10. The method according to claim 1 or 9, wherein in the preparation process of the Pt-based alloy/MOFs catalyst, the ratio of the amount-of-substance of platinum acetylacetonate to the volume of DMF is 0.01 mmol:5 mL; and the solid-to-liquid ratio of terephthalic acid to DMF is (16-20) mg/5 mL.

11. The method according to claim 1, 8 or 9, wherein the ratio of the amount-of-substance of the acetylacetone metal salt to the volume of DMF is (0.01-0.03) mmol:5 mL.

12. The method of claim 1, wherein the Pt-based alloy/MOFs catalyst is washed twice with DMF and ethanol during the preparation process; and the drying is vacuum drying at 120? C.

13. A Pt-based alloy/MOFs catalyst prepared by the preparation method according to any one of claims 1-12.

14. The Pt-based alloy/MOFs catalyst according to claim 13, wherein the catalyst is PtFe.sub.1/UiO-66-NH.sub.2, PtFe.sub.2/UiO-66-NH.sub.2, PtFe.sub.3/UiO-66-NH.sub.2, PtM.sub.2/UiO-66-NH.sub.2, PtFe.sub.2/UiO-66 or PtFe.sub.2/MIL-101(Cr); where M in the PtM.sub.2/UiO-66-NH.sub.2 is Ni or Co.

15. Application of the Pt-based alloy/MOFs catalyst according to claim 13 or 14 in a selective hydrogenation reaction.

16. The application according to claim 15, wherein the selective hydrogenation reaction includes the selective hydrogenation reaction of ?, ?-unsaturated aldehyde and the selective hydrogenation reaction of 3-nitrostyrene.

17. The application according to claim 16, wherein the selective hydrogenation reaction of ?, ?-unsaturated aldehyde is a hydrogenation reaction of cinnamaldehyde.

18. The application according to claim 17, wherein the catalytic conditions for the hydrogenation reaction of cinnamaldehyde are as follows: adding the Pt-based alloy/MOFs catalyst and cinnamaldehyde to the mixture of 2.5 mL of water and 2.5 mL of isopropanol with the added amount of Pt-based alloy/MOFs catalyst of 5 mg and the added amount of cinnamaldehyde of 0.3 mmol, performing ultrasonic treatment for 10 min to obtain a uniform mixture, transferring the mixture to a 25 mL reaction flask, putting on a rubber stopper, performing vacuuming with a vacuum pump for 1 min, then quickly plunging into a self-made hydrogen balloon to make the hydrogen pressure consistent with the atmospheric pressure, and stirring for 12 h at room temperature.

19. The application according to claim 16, wherein the conditions for the selective hydrogenation of 3-nitrostyrene are as follows: adding the Pt-based alloy/MOFs catalyst and 3-nitrostyrene to 5 mL of ethanol with the added amount of Pt-based alloy/MOFs catalyst of 5 mg and the added amount of 3-nitrostyrene of 0.3 mmol, performing ultrasonic treatment for 5 min to obtain a uniform mixture, transferring the mixture to a 25 mL reaction flask, putting on a rubber stopper, performing vacuuming with a vacuum pump for 1 min, then quickly plunging into a self-made hydrogen balloon to make the hydrogen pressure consistent with the atmospheric pressure, and stirring for 5 h at room temperature.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0036] FIG. 1 is a field emission scanning electron microscope image of UiO-66-NH.sub.2;

[0037] FIG. 2 is a TEM image of PtFe.sub.1/UiO-66-NH.sub.2;

[0038] FIG. 3 is a TEM image of PtFe.sub.2/UiO-66-NH.sub.2;

[0039] FIG. 4 is a TEM image of PtFe.sub.3/UiO-66-NH.sub.2;

[0040] FIG. 5 is a TEM image of PtFe.sub.2/UiO-66-NH.sub.2;

[0041] FIG. 6 is an element linear scan diagram of PtFe.sub.2/UiO-66-NH.sub.2;

[0042] FIG. 7 is an element mapping diagram of PtFe.sub.2/UiO-66-NH.sub.2;

[0043] FIG. 8 is a TEM image of PtNi.sub.2/UiO-66-NH.sub.2;

[0044] FIG. 9 is a TEM image of PtCo.sub.2/UiO-66-NH.sub.2;

[0045] FIG. 10 is a TEM image of PtFe.sub.2/UiO-66;

[0046] FIG. 11 is a TEM image of PtFe.sub.2/MIL-101(Cr);

[0047] FIG. 12 is a TEM image of Pt/UiO-66-NH.sub.2 synthesized without terephthalic acid;

[0048] FIG. 13 is a TEM image of Pt/UiO-66-NH.sub.2 synthesized with the addition of terephthalic acid;

[0049] FIG. 14 is a TEM image of PtFe.sub.2/UiO-66-NH.sub.2 synthesized without terephthalic acid;

[0050] FIG. 15 is an XRD pattern of various hydrogenation catalysts;

[0051] FIG. 16 is a schematic diagram of the hydrogenation of cinnamaldehyde;

[0052] FIG. 17 shows the conversion and selectivity of the hydrogenation reaction of cinnamaldehyde catalyzed by Pt/UiO-66-NH.sub.2 over time;

[0053] FIG. 18 shows the conversion and selectivity of the hydrogenation reaction of cinnamaldehyde catalyzed by PtFe.sub.1/UiO-66-NH.sub.2 over time;

[0054] FIG. 19 shows the conversion and selectivity of the hydrogenation reaction of cinnamaldehyde catalyzed by PtFe.sub.2/UiO-66-NH.sub.2 over time;

[0055] FIG. 20 shows the conversion and selectivity of the hydrogenation reaction of cinnamaldehyde catalyzed by PtFe.sub.3/UiO-66-NH.sub.2 over time;

[0056] FIG. 21 shows the conversion of cinnamaldehyde and selectivity of cinnamyl alcohol catalyzed by PtFe.sub.2/UiO-66-NH.sub.2 in multiple cycles of hydrogenation;

[0057] FIG. 22 is a schematic diagram of the hydrogenation of 3-nitrostyrene;

[0058] FIG. 23 shows the conversion and selectivity of the hydrogenation reaction of 3-nitrostyrene catalyzed by Pt/UiO-66-NH.sub.2 over time;

[0059] FIG. 24 shows the conversion and selectivity of the hydrogenation of 3-nitrostyrene catalyzed by PtFe.sub.2/UiO-66-NH.sub.2 over time;

[0060] FIG. 25 shows the conversion of 3-nitrostyrene and the selectivity of 3-aminostyrene catalyzed by PtFe.sub.2/UiO-66-NH.sub.2 in multiple cycles of hydrogenation.

[0061] FIG. 26 is a graph showing the performance of Pt/UiO-66-NH.sub.2 and PtFe.sub.2/UiO-66-NH.sub.2 in catalyzing the dehydrogenation of tetrahydroquinoline to quinoline.

[0062] FIG. 27 shows the hydrogen adsorption isotherm curve of PtFe.sub.2/UiO-66-NH.sub.2 (1 bar, 77 K).

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0063] The present disclosure will be further described below in conjunction with embodiments and drawings.

[0064] The specific embodiments of the present disclosure will be further described below. It should be noted here that the description of these embodiments is used to help understand the present disclosure, but does not constitute a limitation to the present disclosure. In addition, the technical features involved in the various embodiments of the present disclosure described below can be combined with each other as long as they do not conflict with each other.

[0065] The experimental methods in the following examples, unless otherwise specified, are all conventional methods, and the test materials used in the following examples, unless otherwise specified, are all commercially available through conventional commercial channels.

Example 1: Preparation of PtFe/UiO-66-NH.SUB.2 .Catalyst

[0066] (1) Preparation of UiO-66-NH.sub.2: 52 mg of zirconium tetrachloride and 39.5 mg of 2-aminoterephthalic acid were added to 50 mL of DMF, then 6 mL of acetic acid was added thereto, the mixture was stirred at room temperature for 30 min, the resulting mixture was transferred to the liner of a reactor, then the liner of the polytetrafluoroethylene reactor was placed into a high pressure reactor, and the mixture was reacted under high temperature of 120? C. and high pressure for 12 h. The resulting mixture was centrifuged at a speed of 8000 rpm, the supernatant was removed, the remaining was washed twice with DMF and ethanol respectively, and finally subjected to vacuum drying at 120? C. to obtain UiO-66-NH.sub.2.

[0067] The prepared UiO-66-NH.sub.2 was observed with a scanning electron microscope (Hitachi SU8010). As shown in FIG. 1, the MOF has an octahedral structure with uniform size.

[0068] (2) Preparation of PtFe/UiO-66-NH.sub.2: 50 mg of UiO-66-NH.sub.2 was added to 5 mL of DMF, the mixture was subjected to ultrasonic treatment to uniform dispersion (power of 360 W, the time of ultrasonic treatment of 5 min), and then stirred at room temperature for 30 min to obtain a solution A; then 0.01 mmol of platinum acetylacetonate and 18 mg of terephthalic acid were added to the solution A, and stirred at room temperature for 10 min to obtain an uniform solution B; then a certain amount (0.01 mmol, 0.02 mmol, 0.03 mmol) of ferrous acetylacetonate was added to the solution B, the mixture was continued to stir at room temperature for 30 min, the resulting solution was continued to stir at 150? C. for 12 h at a stirring speed of 600 rpm, then the resulting mixture was centrifuged at a speed of 8000 rpm, the supernatant was removed, the remaining was washed twice with DMF and ethanol respectively, and finally dried under vacuum at 60? C. overnight to obtain PtFe/UiO-66-NH.sub.2.

[0069] Wherein, the product with 0.01 mmol of iron acetylacetonate added is named PtFe.sub.1/UiO-66-NH.sub.2, the product with 0.02 mmol of iron acetylacetonate added is named PtFe.sub.2/UiO-66-NH.sub.2, and the product with 0.03 mmol of iron acetylacetonate added is named PtFe.sub.3/UiO-66-NH.sub.2.

[0070] The PtFe.sub.1/UiO-66-NH.sub.2, PtFe.sub.2/UiO-66-NH.sub.2 and PtFe.sub.3/UiO-66-NH.sub.2 prepared above were observed by transmission electron microscope (JEM-1400 Plus, JEOL). As can be seen from the transmission electron micrographs in FIG. 2-4, a large number of particles with very small diameters are uniformly distributed on the surface of UiO-66-NH.sub.2, which proves that the added terephthalic acid can promote the reduction of Pt salts and Fe salts, and is beneficial to the dispersion of the particles. At the same time, it can be seen that adding different amounts of iron acetylacetonate does not destroy the morphology of the MOF, and the size of the metal particles obtained is not very different.

[0071] The PtFe.sub.2/UiO-66-NH.sub.2 prepared above was observed with high-angle annular dark-field scanning TEM (ARM200F, JEOL). As shown in FIG. 5, the brighter particles in the figure are PtFe alloys. The element linear scan analysis of the two PtFe particles pointed by the white arrow shows (FIG. 6) that the distribution trends of Pt and Fe are basically the same, which proves that Pt and Fe form an alloy.

[0072] The PtFe.sub.2/UiO-66-NH.sub.2 prepared above was subjected to element mapping analysis, and the result is shown in FIG. 7. The left image in the figure is the ring-shaped dark field image of the sample, in which the bright place is metal, and the dark place is MOF; The two images on the right are based on the element distribution of the image on the left. It can be proved that there are more Pt and Fe at the same time in the bright place, and the element distribution positions of Pt and Fe are basically the same, which also proves that Pt and Fe form an alloy.

Example 2: Preparation of PtM.SUB.2./UiO-66-NH.SUB.2 .(M=Ni or Co) Catalyst

[0073] (1) The preparation of UiO-66-NH.sub.2 is the same as in Example 1.

[0074] (2) Preparation of PtM.sub.2/UiO-66-NH.sub.2 (M=Ni or Co): 50 mg of UiO-66-NH.sub.2 was added to 5 mL of DMF, the mixture was subjected to ultrasonic treatment to uniform dispersion (power of 360 W, the time of ultrasonic treatment of 5 min), and then stirred at room temperature for 30 min to obtain a solution A; then 0.01 mmol of platinum acetylacetonate and 18 mg of terephthalic acid were added to the solution A, and stirred at room temperature for 10 min to obtain an uniform solution B; then 0.02 mmol of nickel acetylacetonate or cobalt acetylacetonate was added to the solution B, the mixture was continued to stir at room temperature for 30 min, the resulting solution was continued to stir at 150? C. for 12 h at a stirring speed of 600 rpm, then the mixture was centrifuged at a speed of 8000 rpm, the supernatant was removed, the remaining was washed twice with DMF and ethanol respectively, and finally dried under vacuum at 60? C. overnight to obtain PtNi.sub.2/UiO-66-NH.sub.2 and PtCo.sub.2/UiO-66-NH.sub.2.

[0075] The PtNi.sub.2/UiO-66-NH.sub.2 and PtCo.sub.2/UiO-66-NH.sub.2 prepared above were analyzed by transmission electron microscopy (TEM). It can be seen from FIG. 8 and FIG. 9 that the metal particles are uniformly loaded on the UiO-66-NH.sub.2 surface.

Example 3: Preparation of PtFe.SUB.2./UiO-66 and PtFe.SUB.2./MIL-101(Cr) Catalysts

[0076] (1) Preparation of UiO-66: 52 mg of zirconium tetrachloride and 36 mg of terephthalic acid were added to 50 mL of DMF, then 6 mL of acetic acid was added thereto, the mixture was stirred at room temperature for 30 min, the mixed solution was transferred to the liner of a polytetrafluoroethylene reactor, then the liner was placed into a high pressure reactor, the temperature was raised to 120? C., the solvent was volatilized to form a high-pressure environment, then the mixture was reacted under high temperature of 120? C. and high pressure for 12 h, the resulting mixture was centrifuged at 8000 rpm, the supernatant was removed, the remaining was washed twice with DMF and absolute ethanol respectively, and finally subjected to vacuum drying at 120? C. to obtain UiO-66.

[0077] (2) Preparation of MIL-101(Cr): 266.5 mg of chromium trichloride hexahydrate and 166.1 mg of terephthalic acid were dispersed in 7.2 mL of water, stirred vigorously at room temperature for 3 min, the resulting mixture was transferred to the liner of polytetrafluoroethylene reactor, then the liner was placed into a stainless steel reactor, and the mixture was reacted at 210? C. for 24 h. The temperature was naturally cooled to room temperature, then the obtained mixture was transferred to the centrifuge tube and centrifuged at a speed of 1000 rpm for 3 min, the crystalline terephthalic acid was precipitated, the upper mixture was taken, then centrifuged at 5000 rpm for 10 min, and washed twice with DMF and once with absolute ethanol. The obtained solid was placed in a vacuum drying oven, and dried overnight at 150? C. to obtain MIL-101 (Cr).

[0078] (3) Preparation of PtFe.sub.2/MOFs: 50 mg of UiO-66 or MIL-101(Cr) was added to 5 mL of DMF, subjected to ultrasonic treatment to uniform dispersion (power of 360 W, the time of ultrasonic treatment of 5 min), and then stirred at room temperature for 30 min to obtain a solution A; then 0.01 mmol of platinum acetylacetonate and 18 mg of terephthalic acid were added to the solution A, and stirred at room temperature for 10 min to obtain an uniform solution B; then 0.02 mmol of ferrous acetylacetonate was added to the solution B, the mixture was continued to stir at room temperature for 30 min, the resulting solution was continued to stir at 150? C. for 12 h at a stirring speed of 600 rpm, then the mixed solution was centrifuged at a speed of 8000 rpm, the supernatant was removed, the remaining was washed twice with DMF and ethanol respectively, and finally dried under vacuum at 60? C. overnight to obtain PtFe.sub.2/UiO-66 and PtFe.sub.2/MIL-101(Cr).

[0079] The PtNi.sub.2/UiO-66 and PtFe.sub.2/MIL-101(Cr) prepared above were analyzed by transmission electron microscopy (TEM). It can be seen from FIG. 10 that the metal particles are uniformly loaded on the UiO-66 surface; It can be seen from FIG. 11 that the metal particles are uniformly loaded on the PtFe.sub.2/MIL-101(Cr) surface.

Comparative Example 1: Preparation of Pt/UiO-66-NH.SUB.2.Catalyst

[0080] (1) The preparation of UiO-66-NH.sub.2 is the same as in Example 1.

[0081] (2) Preparation of Pt/UiO-66-NH.sub.2:

[0082] Preparation method 1: 50 mg of UiO-66-NH.sub.2 was added to 5 mL of DMF, subjected to ultrasonic treatment to uniform dispersion, and then stirred at room temperature for 30 min to obtain a solution A; then 0.01 mmol of platinum acetylacetonate and 18 mg of terephthalic acid were added to the solution A, and stirred at room temperature for 30 min, the resulting solution was continued to stir at 150? C. for 12 h at a stirring speed of 600 rpm, then the mixed solution was centrifuged at a speed of 8000 rpm, the supernatant was removed, the remaining was washed twice with DMF and ethanol respectively, and finally dried under vacuum at 60? C. overnight to obtain Pt/UiO-66-NH.sub.2.

[0083] Preparation method 2: The specific method is the same as the preparation method 1, except that terephthalic acid is not added during the preparation process.

[0084] The Pt/UiO-66-NH.sub.2 prepared with and without terephthalic acid was observed by transmission electron microscope (JEM-1400 Plus, JEOL). From the transmission electron microscope image of Pt/UiO-66-NH.sub.2 prepared without adding terephthalic acid in FIG. 12, the octahedral structure can also be observed, the size of UiO-66-NH.sub.2 is consistent with the SEM image, but the surface of UiO-66-NH.sub.2 has only relatively sparse metal particles, indicating that the Pt salt has not been well reduced. From the transmission electron microscope image of Pt/UiO-66-NH.sub.2 prepared with terephthalic acid in FIG. 13, it can be seen that a large number of particles with a small particle size are uniformly distributed on the surface of UiO-66-NH.sub.2, which proves that the added terephthalic acid can promote the reduction of Pt salt, and it is conducive to particle dispersion.

Comparative Example 2: Preparation of PtFe.SUB.2./UiO-66-NH.SUB.2 .Catalyst without Adding Terephthalic Acid

[0085] The specific method is the same as in Example 1, except that terephthalic acid is not added during the preparation process.

[0086] The PtFe.sub.2/UiO-66-NH.sub.2 prepared without terephthalic acid was observed by transmission electron microscope (JEM-1400 Plus, JEOL). It can be seen from FIG. 14 that there are larger particles and sparse metal particles on the surface of UiO-66-NH.sub.2, indicating that the Pt salt and Fe salt have not been well reduced.

Comparative Example 3: Preparation of Pt/UiO-66 Catalyst

[0087] (1) The preparation of UiO-66 is the same as in Example 3.

[0088] (2) Preparation of Pt/UiO-66: 50 mg of UiO-66 was added to 5 mL of DMF, subjected to ultrasonic treatment to uniform dispersion, and then stirred at room temperature for 30 min to obtain a solution A; then 0.01 mmol of platinum acetylacetonate and 18 mg of terephthalic acid were added to the solution A, and stirred at room temperature for 30 min, the resulting solution was continued to stir at 150? C. for 12 h at a stirring speed of 600 rpm, then the mixed solution was centrifuged at a speed of 8000 rpm, the supernatant was removed, the remaining was washed twice with DMF and ethanol respectively, and finally dried under vacuum at 60? C. overnight to obtain Pt/UiO-66.

Experimental Example 1: Mass Percentage of Pt and Molar Ratio of Pt to Fe Analysis

[0089] The mass percentage of Pt and molar ratio of Pt to Fe of heterogeneous catalysts (PtFe.sub.1/UiO-66-NH.sub.2, PtFe.sub.2/UiO-66-NH.sub.2, PtFe.sub.3/UiO-66-NH.sub.2, PtFe.sub.2/UiO-66, PtFe.sub.2/MIL-101 (Cr), and Pt/UiO-66-NH.sub.2) were analyzed.

[0090] As shown in Table 1, the Pt content of the various catalysts is roughly the same, which proves that the change of synthesis conditions will not affect the reduction of Pt. The actual ratio of Pt and Fe is equivalent to the feed ratio, which proves that the method of the present disclosure can accurately adjust the ratio of bimetals to obtain a catalyst with the best performance.

TABLE-US-00001 TABLE 1 Mass percentage of Pt and molar ratio of Pt to Fe of various heterogeneous catalysts mass percentage of molar ratio of Pt to No. catalyst Pt/wt % Fe 1 Pt/UiO-66-NH.sub.2 2.77 2 PtFe.sub.1/UiO-66-NH.sub.2 2.64 0.91 3 PtFe.sub.2/UiO-66-NH.sub.2 2.47 0.42 4 PtFe.sub.3/UiO-66-NH.sub.2 2.33 0.23 5 PtFe.sub.2/UiO-66 2.76 0.38 6 PtFe.sub.2/MIL-101 (Cr) 2.53 0.45

Experimental Example 2: X-Ray Powder Diffraction

[0091] The PtFe.sub.1/UiO-66-NH.sub.2, PtFe.sub.2/UiO-66-NH.sub.2 and PtFe.sub.3/UiO-66-NH.sub.2 of Example 1, the PtFe.sub.2/UiO-66 of Example 3, and the Pt/UiO-66-NH.sub.2 of Comparative Example 1, Pt/UiO-66, UiO-66-NH.sub.2 and UiO-66 of Comparative Example 3 were analyzed by X-ray powder diffraction pattern (XRD) using Rigaku's SmartLab instrument. It can be seen from FIG. 15 that the XRD of all samples retain the peaks of the original carrier UiO-66 or UiO-66-NH.sub.2, which proves that this solvothermal method will not damage the crystal form and structure of MOF. In addition, from the enlarged image on the right, it can be seen that there is no peak at around 40 degrees, which proves that no larger metal particles are formed.

Experimental Example 3: Activity and Selectivity Analysis of Selective Catalytic Hydrogenation of Cinnamaldehyde

[0092] Using a typical ?, ?-unsaturated aldehyde-cinnamaldehyde as the catalytic substrate, and the catalytic activity and product selectivity of different catalysts (PtFe.sub.1/UiO-66-NH.sub.2, PtFe.sub.2/UiO-66-NH.sub.2, PtFe.sub.3/UiO-66-NH.sub.2, PtCo.sub.2/UiO-66-NH.sub.2, PtNi.sub.2/UiO-66-NH.sub.2, PtFe.sub.2/MIL-101 (Cr), PtFe.sub.2/UiO-66, Pt/UiO-66-NH.sub.2, Pt/UiO-66, UiO-66-NH.sub.2) were compared. The principle of the hydrogenation of cinnamaldehyde is shown in FIG. 16. Cinnamicaldehyde is hydrogenated into cinnamyl alcohol, hydrocinnamaldehyde and phenylpropanol under the action of catalyst and hydrogen. The ideal product is cinnamyl alcohol.

[0093] The reaction conditions of heterogeneous catalytic hydrogenation are as follows: the catalyst and cinnamaldehyde were added to the mixture of 2.5 mL of water and 2.5 mL of isopropanol with the added amount of catalyst of 5 mg and the added amount of cinnamaldehyde of 0.3 mmol, the resulting mixture was subjected to ultrasonic treatment for 10 min to obtain a uniform mixture, the mixture was transferred to a 25 mL reaction flask, the flask was plunged with a rubber stopper, then vacuuming was carried out with a vacuum pump for 1 min, then a self-made hydrogen balloon was quickly plunged into to make the hydrogen pressure consistent with the atmospheric pressure, and stirred for 12 h at room temperature. Samples were taken every 1 h, extracted with an appropriate amount of ethyl acetate and centrifuged, the supernatant was taken, and the catalytic results were tested by gas chromatography-mass spectrometry (GC-MS).

[0094] As shown in FIG. 17, when Pt/UiO-66-NH.sub.2 is used as the catalyst, as the reaction time increases, cinnamaldehyde is continuously hydrogenated to produce cinnamyl alcohol, hydrocinnamaldehyde and phenylpropanol. After 12 h of reaction, the conversion of cinnamaldehyde is only 48.5%, the selectivity of cinnamyl alcohol in the product is 63.5%, and the performance is average.

[0095] As shown in FIG. 18, when PtFe.sub.1/UiO-66-NH.sub.2 is used as a catalyst, as the reaction time increases, cinnamaldehyde is continuously hydrogenated to produce cinnamyl alcohol, hydrocinnamaldehyde and phenylpropanol. After 12 h of reaction, the conversion of cinnamaldehyde is 98.5%, the selectivity of cinnamyl alcohol in the product is 89.6%, the reaction activity is much higher than that of pure Pt/UiO-66-NH.sub.2, and it can produce cinnamyl alcohol with high selectivity.

[0096] As shown in FIG. 19, when PtFe.sub.2/UiO-66-NH.sub.2 is used as a catalyst, as the reaction time increases, cinnamaldehyde is continuously hydrogenated to produce cinnamyl alcohol, hydrocinnamaldehyde and phenylpropanol. After 12 h of reaction, the conversion of cinnamaldehyde is 98.9%, the selectivity of cinnamyl alcohol in the product is 95.4%, the reaction activity is much higher than that of pure Pt/UiO-66-NH.sub.2, and it can produce cinnamyl alcohol with high selectivity.

[0097] As shown in FIG. 20, when PtFe.sub.3/UiO-66-NH.sub.2 is used as a catalyst, as the reaction time increases, cinnamaldehyde is continuously hydrogenated to produce cinnamyl alcohol, hydrocinnamaldehyde and phenylpropanol. After 12 h of reaction, the conversion of cinnamaldehyde is 98.8%, the selectivity of cinnamyl alcohol in the product is 93.1%, the reaction activity is much higher than that of pure Pt/UiO-66-NH.sub.2, and it can produce cinnamyl alcohol with high selectivity.

[0098] As shown in Table 2, PtCo.sub.2/UiO-66-NH.sub.2, PtNi.sub.2/UiO-66-NH.sub.2, PtFe.sub.2/MIL-101 (Cr) and PtFe.sub.2/UiO-66 also show good conversion and selectivity, the activity is better than that of pure Pt/UiO-66-NH.sub.2 (the conversion and selectivity of Pt/UiO-66 are worse than Pt/UiO-66-NH.sub.2).

[0099] From the above analysis, it can be seen that the PtFe/UiO-66-NH.sub.2 with different amounts of Fe salt is better than the single metal catalyst Pt/UiO-66-NH.sub.2 in terms of catalytic activity and product selectivity (PtFe.sub.2/UiO-66-NH.sub.2 performs best). After 12 h of reaction, the conversion of cinnamaldehyde hydrogenation catalyzed by PtFe/UiO-66-NH.sub.2 is greater than 98%, and it can produce cinnamyl alcohol with selectivity greater than 90%, while the conversion catalyzed by Pt/UiO-66-NH.sub.2 is less than 50%, it is also difficult to form a relatively single product, which proves that by adding Fe salt to form PtFe alloy and thin layer Fe-MOF, the conversion and product selectivity of the catalytic reaction can be greatly improved.

[0100] In addition, after 5 cycles of catalysis using PtFe.sub.2/UiO-66-NH.sub.2 (as shown in FIG. 21), its catalytic performance has not been significantly reduced, and it can still maintain high catalytic activity and product selectivity, which proves that the catalyst has good cycle stability, and further shows that the PtFe/UiO-66-NH.sub.2 obtained in the present disclosure is an excellent catalyst for the selective hydrogenation of ?, ?-unsaturated aldehyde.

TABLE-US-00002 TABLE 2 Conversion and selectivity of various catalysts for catalytic hydrogenation of cinnamaldehyde for 12 h selectivity selectivity selectivity of turnover of of cinnamyl frequency/ No. catalyst conversion/% hydrocinnamaldehyde/% phenylpropanol/% alcohol/% h.sup.?1 1 Pt/UiO-66 21.5 22.0 7.5 70.4 15.4 2 Pt/UiO-66-NH.sub.2 48.5 25.4 11.1 63.5 17.0 3 PtFe.sub.1/UiO-66-NH.sub.2 98.5 10.4 89.6 36.4 4 PtFe.sub.2/UiO-66-NH.sub.2 98.9 0.4 4.1 95.4 37.0 5 PtFe.sub.3/UiO-66-NH.sub.2 98.8 6.8 93.1 41.4 6 PtCO.sub.2/UiO-66-NH.sub.2 92.6 11.8 7.2 80.9 39.6 7 PtNi.sub.2/UiO-66-NH.sub.2 98.0 3.7 70.8 25.5 36.2 8 PtFe.sub.2/MIL-101 (Cr) 99.9 0.49 29.0 70.5 38.4 9 PtFe.sub.2/UiO-66 74.7 2.2 1.6 96.2 26.4 10 UiO-66-NH.sub.2 N.D.

Experimental Example 4: Analysis of Activity and Selectivity of Selective Catalytic Hydrogenation of 3-Nitrostyrene

[0101] For the selective catalytic hydrogenation of 3-nitrostyrene, the catalytic ability and product selectivity of different catalysts were compared. The principle of the hydrogenation of 3-nitrostyrene is shown in FIG. 22. 3-Nitrostyrene can be hydrogenated to generate 3-aminostyrene or 1-ethyl-3-nitrobenzene under certain conditions, and then further hydrogenated to generate 3-ethylaniline. The ideal product is 3-aminostyrene.

[0102] The reaction conditions of heterogeneous catalytic hydrogenation are as follows: the catalyst and 3-nitrostyrene were added to 5 mL of ethanol with the added amount of catalyst of 5 mg and the added amount of 3-nitrostyrene of 0.3 mmol, the resulting mixture was subjected to ultrasonic treatment for 5 min to obtain a uniform mixture, the mixture was transferred to a 25 mL reaction flask, the flask was plunged with a rubber stopper, then vacuuming was carried out with a vacuum pump for 1 min, then a self-made hydrogen balloon was quickly plunged into to make the hydrogen pressure consistent with the atmospheric pressure, stirred for 5 h at room temperature, samples were taken every 1 h, and the catalytic results were tested by gas chromatography-mass spectrometry (GC-MS).

[0103] As shown in FIG. 23, when Pt/UiO-66-NH.sub.2 is used as a catalyst, as the reaction time increases, cinnamaldehyde is continuously hydrogenated to produce 3-aminostyrene or 1-ethyl-3-nitrobenzene, and then further hydrogenated to generate 3-ethylaniline. After 3 h of reaction, the conversion of 3-nitrostyrene exceeds 90%, the selectivity of 3-aminostyrene in the product is 35.3%, and the product selectivity is not good.

[0104] As shown in FIG. 24, when PtFe.sub.2/UiO-66-NH.sub.2 is used as a catalyst, as the reaction time increases, cinnamaldehyde is continuously hydrogenated to produce 3-aminostyrene or 1-ethyl-3-nitrobenzene, and then further hydrogenated to generate 3-ethylaniline. After 2 h of reaction, the conversion of 3-nitrostyrene reaches 96.1%, and the selectivity of 3-aminostyrene in the product is 92.3%, which proves that the catalyst can also be used for the selective hydrogenation of 3-nitrostyrene and obtain 3-aminostyrene with a high yield.

[0105] It can be seen from the above analysis that PtFe.sub.2/UiO-66-NH.sub.2 can well catalyze the hydrogenation of 3-nitrostyrene to obtain 3-aminostyrene, and prolonging the reaction time will not produce too much final product 3-ethylaniline, while pure Pt/UiO-66-NH.sub.2 is far inferior to PtFe.sub.2/UiO-66-NH.sub.2 in terms of catalytic activity and product selectivity, which proves that the PtFe.sub.2/UiO-66-NH.sub.2 of the present disclosure has better performance in selective catalytic hydrogenation and has greater application value.

[0106] In addition, after 5 cycles of catalysis with PtFe.sub.2/UiO-66-NH.sub.2 (FIG. 25), it is found that the catalytic performance did not significantly decrease, which proves that the catalyst has good cycle stability. It can be seen that the catalyst of the present disclosure has high-efficiency selective hydrogenation performance and has good application prospects in hydrogen storage and hydrogenation and dehydrogenation.

Experimental Example 5: Catalytic Dehydrogenation of Tetrahydroquinoline

[0107] The conditions for the dehydrogenation of tetrahydroquinoline are as follows: 10 mg of Pt/MOFs catalyst and 0.1 mmol of tetrahydroquinoline were added to a mixture of 2 mL of xylene and 2 mL of water, the resulting mixture was subjected to ultrasonic treatment for 5 min, and heated to 100? C. to react for 20 h in the condensing reflux device and under stirring conditions. After the reaction, the mixture was transferred to a centrifuge tube and centrifuged, 100 ?L of the supernatant was taken into a 1.5 mL sample bottle, 900 ?L of ethanol was added thereto and mixed evenly. The catalytic results were tested by chromatography-mass spectrometer (GC-MS). The result is shown in FIG. 26. It can be seen from FIG. 26 that the Pt/MOFs catalyst prepared by the present disclosure has excellent catalytic performance for the dehydrogenation of tetrahydroquinoline to prepare quinoline.

Experimental Example 6: Hydrogen Storage Capacity

[0108] The hydrogen storage capacity of 100 mg of PtFe.sub.2/UiO-66-NH.sub.2 was measured under the conditions of 1 bar and 77 K using a hydrogen adsorption device. The test results are shown in FIG. 27. It can be seen from FIG. 27 that the PtFe.sub.2/UiO-66-NH.sub.2 catalyst prepared by the present disclosure has excellent hydrogen storage performance under normal pressure.

[0109] The description of the above embodiments is only used to help understand the method and the core idea of the present disclosure. It should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present disclosure, several improvements and modifications can be made to the present disclosure, and these improvements and modifications also fall within the protection scope of the claims of the present disclosure. Various modifications to these embodiments are obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present disclosure. Therefore, the present disclosure will not be limited to the embodiments shown in this document, but should conform to the widest scope consistent with the principles and novel features disclosed in this document.