A method for kilogram-scale preparation of metal-organic thin films

Abstract

The application relates to the technical field of metal organic thin layer material preparation, in particular to a kilogram-level preparation method of metal organic thin layer material. The preparation method comprises the following steps: S1, adding zirconium tetrachloride and H2BPYDC into a polytetrafluoroethylene reaction kettle, dissolving the zirconium tetrachloride and the H2BPYDC, and then adding a composite; S2, sequentially adding a DMF solution of palladium fluoroacetate, a catalyst and concentrated hydrochloric acid into the reaction kettle; S3, transferring the reaction kettle into an oven, centrifuging to obtain a cyan suspension after 18-20 hours, dispersing the cyan suspension in a DMF solution in batches at 60 DEG C, placing for 5-6 hours, removing unreacted substrates, and obtaining a solid; S4, cleaning the solid obtained in S3 by using DMF and tetrahydrofuran respectively, and vacuum drying for 12 hours to obtain the metal organic thin layer material. The kilogram-level preparation method of metal organic thin layer material is provided, so as to solve the problems of low preparation yield, slow rate and difficulty in kilogram-level preparation of metal organic thin layer material in the related art.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of metal-organic thin layer material preparation, and particularly relates to a kilogram-level preparation method of metal-organic thin layer material. BACKGROUND

[0002] Metal-organic thin layer material (MOL) is a kind of metal-organic functional material with two-dimensional layered structure, which belongs to the "thin layer" derivative of metal-organic framework (MOFs), and the core feature is that metal ions / metal clusters (nodes) are connected with organic ligands through coordination bonds to form a sheet structure of single atomic layer or a few atomic layers, the thickness is usually 1-10 nm, and the lateral size can extend from several hundred nanometers to microns, which has unique structure and performance, and has wide application prospects in the fields of building material thermal insulation and sound insulation.

[0003] Traditional building organic insulation materials (such as polystyrene board EPS and extruded board XPS) have low thermal conductivity, but poor temperature resistance. Inorganic insulation materials (such as rock wool and glass wool) have high temperature resistance but high thermal conductivity and performance degradation after absorbing moisture. MOL can balance low thermal conductivity and high temperature resistance.

[0004] The preparation method of metal-organic thin layer material usually includes traditional solvothermal method, mechanical grinding and ultrasonic peeling method, and chemical vapor deposition method. The traditional solvothermal method depends on high temperature and high pressure, the reaction kinetics is slow, the reaction time is as long as several hours to several days, and the single yield is usually milligram level. The yield of mechanical grinding and ultrasonic peeling method is relatively low, usually about 15%, and the structure is easy to be damaged, which is difficult to realize large-scale kilogram-level production. The chemical vapor deposition method has high requirements for equipment and process, which is also not conducive to large-scale production, and cannot become the core component of the new generation of building thermal insulation materials, so it cannot be widely used in civil buildings, industrial buildings and other fields. SUMMARY

[0005] The present application provides a kilogram-level preparation method of metal-organic thin layer material to solve the problems of low yield, slow rate and difficulty in kilogram-level preparation of metal-organic thin layer material in the related art.

[0006] To achieve the above purpose, the present application provides a kilogram-level preparation method of metal-organic thin layer material, which comprises the following steps:

[0007] S1, adding zirconium tetrachloride and H2BPYDC into a polytetrafluoroethylene reactor, dissolving, and then adding a composite;

[0008] S2, adding a DMF solution of palladium fluoroacetate, a catalyst, and concentrated hydrochloric acid into the reactor in sequence;

[0009] S3, transfer the reaction kettle to a 75-80℃ oven, centrifuge to obtain a blue suspension after 18-20h, disperse the blue suspension in DMF solution in batches at 60℃, place for 5-6h, remove the unreacted substrate to obtain a solid;

[0010] S4, use DMF and tetrahydrofuran to clean the solid obtained in S3, vacuum dry at 110-120℃ for 12h to obtain a metal organic thin layer material.

[0011] Preferably, in S1, the complex is a DMF solution of hydroxyethyl cellulose and sodium methylene bis-methyl naphthalene sulfonate at a mass ratio of 1:(1-1.2), and the sum of the mass of the hydroxyethyl cellulose and sodium methylene bis-methyl naphthalene sulfonate is 0.1-0.5% of the mass of zirconium tetrachloride.

[0012] Preferably, in S1, the complex is dispersed before being added, and the dispersion power is 200-300W and the dispersion time is 5-10min.

[0013] Preferably, in S1, the mass ratio of zirconium tetrachloride to H2BPYDC is (7-7.5):9.

[0014] Preferably, in S2, the catalyst is added in an amount of 1-1.2% of the mass of H2BPYDC, and the catalyst comprises dimethylamine sulfonyl chloride and a carrier, and the mass ratio of the dimethylamine sulfonyl chloride to the carrier is 1:(2-3), and the carrier is at least one of povidone and micronized silica gel.

[0015] Preferably, the catalyst comprises dimethylamine sulfonyl chloride, povidone and micronized silica gel at a mass ratio of 1:1.5:1.5.

[0016] Preferably, in S2, the concentration of the DMF solution of palladium fluoroacetate is 0.83-1mmol / L.

[0017] Preferably, in S2, the concentration of the concentrated hydrochloric acid is 35-36.2wt%.

[0018] The technical scheme provided in the application has the following beneficial effects:

[0019] The application provides a kilogram-level preparation method of a metal organic thin layer material, uses a complex and a catalyst to activate the carboxyl group of H2BPYDC, reduces the activation energy of the coordination reaction, shortens the reaction time and improves the reaction efficiency; fluorine palladium acetate is selected as the Pd source, and the catalyst carrier adsorbs Pd 2+ by high specific surface area, and sufficient active sites are provided, which avoids the aggregation of Pd 2+The agglomeration ensures uniform embedding of the Zr-MOL thin layer on the surface; both hydroxyethyl cellulose and methylene bis sodium methyl naphthalene sulfonate are easily soluble in N,N-dimethylformamide (DMF), without the need for additional cosolvents, and can be completely removed (without residue) by simple DMF-ethanol washing afterwards, which not only simplifies the post-processing procedure of kilogram-level production, but also avoids the introduction of impurities affecting the purity of the product; through the improvement of the final yield, the effective utilization rate of raw materials is improved, and then kilogram-level preparation is realized, which has broad application prospects in building thermal insulation materials. BRIEF DESCRIPTION OF DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0021] Figure 1 SEM, TEM and HRTEM images of the metal organic thin layer material Pd / Zr-MOL prepared in Example 1 provided by the present application;

[0022] Figure 2 AFM image of the metal organic thin layer material Pd / Zr-MOL prepared in Example 1 provided by the present application;

[0023] Figure 3 High-angle annular dark field scanning transmission electron microscope and corresponding EDX element mapping test diagram provided by the present application. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor belong to the scope of protection of the present application.

[0025] Reference Figures 1-3 As shown in the drawings, the present application provides a kilogram-level preparation method of metal organic thin layer material.

[0026] Example 1

[0027] The kilogram-level preparation method of metal organic thin layer material provided in the present embodiment includes the following steps:

[0028] S101, 630 mg of zirconium tetrachloride and 810 mg of H2BPYDC were added to a 200 mL polytetrafluoroethylene reaction kettle and dissolved, and then a complex was added;

[0029] The complex was a mixture of 1.26 mg of hydroxyethyl cellulose, 1.26 mg of methylene bis sodium methyl naphthalene sulfonate, and 5 mL of DMF (ultrasonic dispersion for 5 min).

[0030] S102, 120 mL of a DMF solution containing 0.1 mmol of palladium fluoroacetate, 8.4 mg of a catalyst, and 4.5 mL of concentrated hydrochloric acid (36 wt%) were sequentially added to the reaction kettle;

[0031] The catalyst was a mixture of 2.1 mg of dimethylamine sulfonate, 3.15 mg of povidone, and 3.15 mg of micro-silica gel (industrial grade, specific surface area 250 m 2 / g).

[0032] S103, the reaction kettle was transferred to an 80°C oven, and after 20 h, a blue suspension was obtained by centrifugation. The blue suspension was dispersed in a DMF solution at 60°C in batches, and after 6 h, the unreacted substrate was removed to obtain a solid;

[0033] S104, the solid obtained in S103 was washed with DMF and tetrahydrofuran three times, respectively, and dried at 120°C under vacuum for 12 h to obtain 960 mg of metal-organic thin-layer material Pd / Zr-MOL, with a yield of about 65.37%.

[0034] Example 2

[0035] The kilogram-level preparation method of the metal-organic thin-layer material provided in this embodiment includes the following steps:

[0036] S201, 675 mg of zirconium tetrachloride and 810 mg of H2BPYDC were added to a 200 mL polytetrafluoroethylene reaction kettle and dissolved, and then a complex was added;

[0037] The complex was a mixture of 0.33 mg of hydroxyethyl cellulose, 0.345 mg of methylene bis sodium methyl naphthalene sulfonate, and 3 mL of DMF (ultrasonic dispersion for 5 min).

[0038] S202, 120 mL of a DMF solution containing 0.12 mmol of palladium fluoroacetate, 9.72 mg of a catalyst, and 4.5 mL of concentrated hydrochloric acid (35 wt%) were sequentially added to the reaction kettle;

[0039] The catalyst was a mixture of 3.24 mg of dimethylamine sulfonate and 6.48 mg of povidone.

[0040] S203, transfer the reaction kettle to an 80°C oven, centrifuge to obtain a blue suspension after 20h, disperse the blue suspension in DMF solution in batches at 60°C, stand for 6h, remove the unreacted substrate to obtain a solid;

[0041] S204, wash the solid obtained in S203 with DMF and tetrahydrofuran three times respectively, vacuum dry at 120°C for 12h to obtain a metal-organic thin-layer material Pd / Zr-MOL 971mg, yield 64%.

[0042] Example 3

[0043] The kilogram-level preparation method of the metal-organic thin-layer material provided in this example includes the following steps:

[0044] S301, add 630mg of zirconium tetrachloride and 810mg of H2BPYDC to a 200mL polytetrafluoroethylene reaction kettle after dissolving, and then add a complex;

[0045] The complex is a mixture of 1.43mg of hydroxyethyl cellulose, 1.72mg of methylene bis sodium naphthalene sulfonate, and 5mL of DMF (ultrasonic dispersion for 5min).

[0046] S302, sequentially add 120mL of DMF solution containing 0.1mmol of palladium fluoroacetate, 8.1mg of catalyst, and 4.5mL of concentrated hydrochloric acid (36.2wt%) to the reaction kettle;

[0047] The catalyst is a mixture of 2.1mg of dimethylamine sulfonate and 6mg of micro-powder silica gel (industrial grade, specific surface area 250m 2 / g).

[0048] S303, transfer the reaction kettle to a 75°C oven, centrifuge to obtain a blue suspension after 18h, disperse the blue suspension in DMF solution in batches at 60°C, stand for 5h, remove the unreacted substrate to obtain a solid;

[0049] S304, wash the solid obtained in S303 with DMF and tetrahydrofuran three times respectively, vacuum dry at 110°C for 12h to obtain a metal-organic thin-layer material Pd / Zr-MOL 892mg, yield 60.72%.

[0050] Comparative Example 1

[0051] The difference between it and Example 1 is that the palladium fluoroacetate in step S102 is replaced with an equal amount of palladium chloride, and no catalyst is added, to obtain a metal-organic thin-layer material Pd / Zr-MOL 607mg, yield 40.94%.

[0052] Comparative Example 2

[0053] The difference between it and Example 1 is that the palladium fluoroacetate in step S102 is replaced with an equivalent amount of palladium chloride, and the catalyst is replaced with 2.1 mg of dimethylamine sulfuryl chloride, i.e. no carrier is added, to obtain the metal-organic thin-layer material Pd / Zr-MOL 653 mg, with a yield of 44.05%.

[0054] Comparative Example 3

[0055] The difference between it and Example 1 is that no composite is added in step S101 to obtain the metal-organic thin-layer material Pd / Zr-MOL 659 mg, with a yield of 44.45%.

[0056] Comparative Example 1 uses palladium chloride, which has poor dissociation, and Comparative Example 2, although retaining part of the catalyst, has poor catalytic effect due to the lack of a carrier.

[0057] The metal-organic thin-layer material prepared in Example 1 is characterized.

[0058] Referring to Figure 1 , which are respectively the SEM, TEM and HRTEM images of the metal-organic thin-layer material Pd / Zr-MOL prepared in Example 1, it can be seen from Figure 1 the SEM image of (a) that the metal-organic thin-layer material prepared in Example 1 is an ultrathin nanosheet without regular shape, with a transverse size close to the micron level; from Figure 1 the TEM image of (b), it can be seen that the ultrathin nanosheet is multi-layer stacked, with obvious two-dimensional material characteristics; further referring to Figure 1 the HRTEM image of (c), it is shown that the HRTEM image indicates that no visible Pd nanoparticles are formed, indicating that the Pd ions are not reduced into nanoparticles in the low-temperature DMF solvothermal process.

[0059] Referring to Figure 2 , which is the AFM (atomic force microscope) image of the metal-organic thin-layer material Pd / Zr-MOL prepared in Example 1, the thickness of the ultrathin nanosheet is about 1.5 nm, the transverse size of the nanosheet is about 1.5 μm, and the nanosheet has no regular shape, as measured by AFM characterization.

[0060] Referring to Figure 3 , in order to further confirm the ultrathin layer structure of Pd / Zr-MOL prepared in Example 1, we carried out high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) and corresponding EDX element mapping tests to study the element distribution characteristics of the ultrathin layer. Figure 3 The EDX element mapping of Figure 3 b), N (Figure 3 c), O ( Figure 3 d), Zr ( Figure 3 e) and Pd( Figure 3 f) Elements; among which C, N, and O are present in higher amounts and are evenly distributed, corresponding to denser color highlights. Zr and Pd are present in relatively lower amounts and are distributed in multiple thin-layer stacking areas, relatively evenly distributed on the lamellar structure.

[0061] Furthermore, the metal-organic thin-film material Pd / Zr-MOL prepared in Example 1 of this application was applied to the CO2 hydrogenation performance test.

[0062] At a temperature of 300℃, a gas ratio of N2 / CO2 / H2 = 1:2:6, a pressure of 3.0 MPa, and a space velocity of 13500 mL·h, the following conditions were met: -1 ·g -1 Under the specified conditions, the catalytic performance of Pd / Zr-MOL prepared in Example 1 (1.5 nm), Pd / MOL (25 nm), and three-dimensional Pd / UiO-67-bpy were investigated. The catalytic results showed that the CO2 conversion rates of Pd / Zr-MOL prepared in Example 1 (1.5 nm), Pd / MOL (25 nm), and three-dimensional Pd / UiO-67-bpy were 19.66%, 12.1%, and 10.5%, respectively, with CO selectivities of 98%, 89%, and 73%, respectively. The 1.5 nm Pd / Zr-MOL exhibited the highest CO2 conversion rate and CO selectivity, mainly attributed to the fully exposed Pd active sites in the ultrathin layer structure, and the non-porous structure and smaller BET specific surface area which facilitated CO molecule desorption.

[0063] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A method for preparing a kilogram-scale metal-organic thin-film material, characterized in that, It includes the following steps: S1. Add zirconium tetrachloride and H2BPYDC to the polytetrafluoroethylene reactor and dissolve them, then add the composite. The complex is a DMF solution of hydroxyethyl cellulose and sodium methylene dimethylnaphthalene sulfonate in a mass ratio of 1:(1~1.2), wherein the sum of the masses of hydroxyethyl cellulose and sodium methylene dimethylnaphthalene sulfonate is 0.1~0.5% of the mass of zirconium tetrachloride. The mass ratio of zirconium tetrachloride to H2BPYDC is (7~7.5):9; S2. Add the DMF solution of palladium fluoroacetate, the catalyst, and concentrated hydrochloric acid to the reaction vessel in sequence; The concentration of the palladium fluoroacetate DMF solution is 0.83~1 mmol / L; The catalyst is added at a rate of 1 to 1.2% of the mass of H2BPYDC. The catalyst comprises dimethylaminosulfonyl chloride and a support, wherein the mass ratio of dimethylaminosulfonyl chloride to the support is 1:(2 to 3), and the support is at least one of polyvinyl ketone and micronized silica gel. The concentration of the concentrated hydrochloric acid is 35~36.2 wt%; S3. Transfer the reaction vessel to an oven at 75~80℃ and place it for 18~20h. Centrifuge to obtain a blue suspension. Disperse the blue suspension in batches in DMF solution at 60℃ and place it for 5~6h. Remove the unreacted substrate to obtain a solid. S4. The solid obtained in S3 is washed with DMF and tetrahydrofuran respectively, and then dried under vacuum at 110~120℃ for 12h to obtain a metal-organic thin film material.

2. The method for preparing the metal-organic thin-film material at the kilogram scale as described in claim 1, characterized in that: In step S1, the complex is first dispersed before being added, with a dispersion power of 200-300W and a dispersion time of 5-10 minutes.

3. The method for preparing the metal-organic thin-film material at the kilogram scale as described in claim 1, characterized in that: The catalyst comprises dimethylaminosulfonyl chloride, polyvinyl ketone, and micronized silica gel in a mass ratio of 1:1.5:1.5.

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