Mof / cof composite based on in-situ embedding of metal clusters, preparation method and application thereof

Abstract

The application discloses a kind of MOF / COF composite material based on metal cluster in-situ embedding and preparation method and application, to solve the technical problems that existing photocatalytic activity functional catalyst has low catalytic activity and target product selectivity is poor.Based on the preparation method of MOF / COF composite material of metal cluster in-situ embedding, it includes: obtaining metal target material, obtaining metal cluster solution according to metal target material;Metal salt and organic ligand are added in N,N-dimethylformamide, after being mixed uniformly, aqueous glacial acetic acid is added, and MOF material is obtained by reaction;MOF material and COF monomer are dissolved in mixed solvent of mesitylene and 1,4-dioxane, and glacial acetic acid is added, and MOF / COF composite material is obtained by solvothermal reaction;MOF / COF composite material and mesitylene are added in metal cluster solution, after being mixed uniformly, glacial acetic acid is added, and solvothermal reaction is carried out, after cooling, the MOF / COF composite material of metal cluster in-situ embedding is obtained.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of photo-thermal catalytic material preparation, and more particularly to a MOF / COF composite material based on in-situ embedding of metal clusters and a preparation method and application thereof. BACKGROUND

[0002] Photocatalytic water splitting for hydrogen production and green hydrogen transfer storage is an efficient integration of solar energy to chemical energy conversion and application, which has excellent application prospects in sustainable energy utilization and conversion. Solar energy, as a rich and cheap clean energy in nature, can drive energy upgrading and conversion. However, the utilization rate of solar water splitting for hydrogen production is unsatisfactory due to the limited photon utilization and slow carrier separation kinetics of the reaction system. At the same time, the storage of green hydrogen produced is limited by technology, which has been one of the great challenges in the industry.

[0003] Biomass derivatives can be converted into high-value chemicals and fuels through hydrogenation reactions, which can greatly improve human demand for materials. Inspired by this, solar water splitting for hydrogen production and biomass hydrogenation conversion can be coupled, which is expected to achieve efficient conversion of solar energy into new energy and chemicals. However, the integration of this coupled reaction puts higher requirements on the design and preparation of multifunctional catalytic materials. In recent years, representative research has designed a few multifunctional catalysts, which have made great progress in photocatalytic water splitting for hydrogen production and biomass high-value conversion. Different photocatalytic active functional catalysts, such as metal-free semiconductor polymers, photoactive metal-organic framework materials (MOF), covalent organic frameworks (COF), and multi-component composite catalysts, have been widely studied in photocatalytic water splitting for hydrogen production and catalytic hydrogenation of furfural. However, due to the easy detachment of active components from the catalytic system, and the inability to maximize the utility of functional catalysts, these single strategies are difficult to fundamentally solve the technical problems of low catalytic activity and poor selectivity of target products. SUMMARY

[0004] The present application aims to provide a MOF / COF composite material based on in-situ embedding of metal clusters and a preparation method and application thereof, which is used to solve the technical problems of low catalytic activity and poor selectivity of target products of existing photocatalytic active functional catalysts. In view of this, the present application is realized by the following scheme.

[0005] In a first aspect, the present application provides a preparation method of a MOF / COF composite material based on in-situ embedding of metal clusters, comprising:

[0006] obtaining a metal target material, placing the metal target material in 1,4-dioxane, and irradiating the metal target material with a laser beam under ultrasonic assistance to obtain a metal cluster solution containing metal particles;

[0007] Add metal salt and organic ligand to N,N-dimethylformamide, mix well, add glacial acetic acid aqueous solution, and react at a temperature of 100-130°C for 12-24 hours to obtain MOF material;

[0008] The MOF material and COF monomer are dissolved in a mixed solvent of mesitylene and 1,4-dioxane, and glacial acetic acid is added. After freezing and vacuuming, the mixture is subjected to solvent thermal reaction for 48 to 72 hours to obtain a MOF / COF composite material;

[0009] The MOF / COF composite material and mesitylene are added to the metal cluster solution, mixed evenly, and then glacial acetic acid is added. The mixture is subjected to solvent thermal reaction at a temperature of 100-130° C. for 48-72 hours. After cooling, a MOF / COF composite material with metal clusters embedded in situ is obtained.

[0010] Compared with the prior art, in the preparation method of the MOF / COF composite material based on in-situ embedding of metal clusters of the application, after the metal target is obtained, the metal target is placed in 1,4-dioxane, and a metal cluster solution containing metal particles can be obtained by irradiating the metal target with a laser beam, and the metal particles can be prevented from agglomerating in 1,4-dioxane under the assistance of ultrasonic waves; in the process of obtaining the MOF material, metal ions and organic ligands are combined through coordination bonds to form a MOF material with a network structure, and the addition of an ice acetic acid aqueous solution can improve the reaction rate; in the process of obtaining the MOF / COF composite material, an equal volume of mesitylene and 1,4-dioxane with good solubility is used as a mixed solvent to dissolve the MOF material and the COF monomer, and the addition of ice acetic acid can improve the reaction rate and promote the polymerization reaction of the COF monomer, so that the COF monomer is polymerized on the surface or inside of the MOF material to obtain the MOF / COF composite material, in this process, the mixed solution is subjected to freezing and vacuumizing treatment to remove impurities such as oxygen and water that may exist in the mixed solution, thereby improving the purity and efficiency of the reaction; in the process of adding the MOF / COF composite material and mesitylene to the metal cluster solution, the temperature and time of the solvothermal reaction are controlled, so that the metal cluster solution (colloid) can replace 1,4-dioxane in the MOF / COF composite material in-situ to obtain the MOF / COF composite material in which metal clusters are in-situ embedded; in this process, the addition of ice acetic acid can improve the solvothermal reaction efficiency. Through the above technical scheme of the application, the light capture capability of the MOF / COF material is regulated and improved, the separation dynamics of the charge carriers thereof is improved, and the water decomposition dynamics and the hydrogenation rate of the biomass derivative are promoted. Specifically, through the above technical scheme of the application, the metal clusters are in-situ embedded into the MOF / COF, the MOF / COF material anchors the metal clusters to the MOF / COF framework or the interlayer through the pore channel or interlayer confinement effect, thereby improving the light capture capability of the MOF / COF material and improving the disadvantage of insufficient active sites, further, the slippage of the COF layer in the MOF / COF material and the escape behavior of the active sites due to insufficient anchoring sites can be inhibited, and the adsorption and activation of water molecules and reactant furfural molecules at the active center are effectively promoted, thereby significantly enhancing the electron and hole separation capability and improving the furfural hydrogenation reaction rate. Through the above technical scheme of the application, the technical problems of low catalytic activity and poor selectivity of the target product of the existing functional catalyst with photocatalytic activity are solved.

[0011] Further, in the preparation method of the MOF / COF composite material based on in-situ embedding of metal clusters of the application, the metal target includes one or more of a platinum target, a copper target, a cobalt target and a nickel target; and / or, the metal target is a metal wafer.

[0012] Further, in the preparation method of the MOF / COF composite material based on in-situ embedding of metal clusters of the present application, the metal salt comprises zirconium chloride, iron chloride, copper nitrate hydrate and titanium acid isopropyl; and / or,

[0013] The organic ligand comprises 2-amino terephthalic acid, 2,5-diamino terephthalic acid and 2-hydroxy terephthalic acid.

[0014] Further, in the preparation method of the MOF / COF composite material based on in-situ embedding of metal clusters of the present application, the COF monomer comprises tri-aldehyde-based phloroglucinol and p-phenylenediamine; and / or,

[0015] In the process of adding the MOF / COF composite material and mesitylene into the metal cluster solution, the mass ratio of the metal cluster solution to the MOF / COF composite material is 1: (4-6), and the volume of the mesitylene is equal to that of the metal cluster solution.

[0016] Further, in the preparation method of the MOF / COF composite material based on in-situ embedding of metal clusters of the present application, the metal cluster solution is a colloidal solution; and / or,

[0017] The content of metal particles in the metal cluster solution is 0.05-0.5wt%.

[0018] Further, in the preparation method of the MOF / COF composite material based on in-situ embedding of metal clusters of the present application, in the process of irradiating the metal target with a laser beam under the assistance of ultrasonic waves, the laser beam comprises a non-focused laser beam; and / or,

[0019] The output wavelength of the laser beam is 1064nm, the pulse frequency is 20-40Hz, the output spot diameter is 5-10mm, the energy density of the laser beam irradiation is 800-1600mJ / cm 2 , and the irradiation time is 10-30min; and / or,

[0020] The temperature of the 1,4-dioxane is -20-0℃, and the frequency of the ultrasonic wave is 20-40kHz.

[0021] Further, in the preparation method of the MOF / COF composite material based on in-situ embedding of metal clusters of the present application, in the process of adding the metal salt and the organic ligand into N,N-dimethylformamide, the mass ratio of the metal salt to the organic ligand is 1: (1-3), and the mass ratio of the N,N-dimethylformamide to the metal salt is 1: (2-6); and / or,

[0022] The mass ratio of glacial acetic acid to water in the aqueous glacial acetic acid solution is 1: (40-60).

[0023] Further, in the preparation method of the metal cluster in-situ embedded MOF / COF composite material of the present application, the MOF material and COF monomers are dissolved in a mixed solvent of mesitylene and 1, 4-dioxane, the mass ratio of the MOF material to the COF monomers is 1: (1~5), the mass ratio of the MOF material to the 1, 4-dioxane is 1: (0.03~0.1), and the volume of mesitylene in the mixed solvent is equal to that of the 1, 4-dioxane; and / or,

[0024] In the metal cluster in-situ embedded MOF / COF composite material, the mass ratio of the MOF material to the COF material is 1: (1~5), and the mass ratio of the metal to the MOF material is 1: (200~2000).

[0025] In the second aspect, the present application provides a metal cluster in-situ embedded MOF / COF composite material, which is prepared by using the above-mentioned preparation method of the metal cluster in-situ embedded MOF / COF composite material; in the metal cluster in-situ embedded MOF / COF composite material, the mass ratio of the MOF material to the COF material is 1: (1~5), and the mass ratio of the metal to the MOF material is 1: (200~2000).

[0026] Compared with the prior art, the metal cluster in-situ embedded MOF / COF composite material of the present application has the same beneficial effects as the above-mentioned preparation method of the metal cluster in-situ embedded MOF / COF composite material, which will not be repeated here.

[0027] In the third aspect, the present application provides the application of the above-mentioned metal cluster in-situ embedded MOF / COF composite material in photocatalytic water splitting and furfural aqueous phase hydrogenation reaction. BRIEF DESCRIPTION OF DRAWINGS

[0028] The accompanying drawings, which are included to provide a further understanding of the present application, form a part of the present application and illustrate the illustrative embodiments of the present application and its description, which do not constitute improper limitations on the present application. In the drawings:

[0029] Figure 1 It is a process schematic diagram for the application of the metal cluster in-situ embedded MOF / COF composite material of the present application;

[0030] Figure 2 It is a scanning electron microscope schematic diagram of the MOF material UiO-66-NH2 in Example 1 of the present application;

[0031] Figure 3 It is a scanning electron microscope schematic diagram of the COF material TPpa-1-COF in Example 1 of the present application;

[0032] Figure 4 Schematic diagram of transmission electron microscopy of the MOF / COF composite material Pt@MOF / COF with in-situ embedded metal clusters in Example 1 of the present invention at 50 nm;

[0033] Figure 5 Schematic diagram of transmission electron microscopy of the MOF / COF composite material Pt@MOF / COF with in-situ embedded metal clusters in Example 1 of the present invention at 20 nm;

[0034] Figure 6 Schematic diagram of a scanning electron microscope of a MOF / COF composite material in which metal clusters are in situ embedded in Example 1 of the present invention;

[0035] Figure 7 Schematic diagram of the MOF / COF composite material with in-situ embedding of metal clusters in Example 1 of the present invention;

[0036] Figure 8 This is a scanning electron microscope diagram of the MOF / COF composite material with in-situ embedded metal clusters in Example 2 of the present invention;

[0037] Figure 9 Schematic diagram of the MOF / COF composite material with in-situ embedding of metal clusters in Example 2 of the present invention;

[0038] Figure 10 This is a scanning electron microscope diagram of the MOF / COF composite material with in-situ embedded metal clusters in Example 3 of the present invention;

[0039] Figure 11 Schematic diagram of the MOF / COF composite material with in-situ embedding of metal clusters in Example 3 of the present invention;

[0040] Figure 12 Schematic diagram of the photocatalytic water splitting performance of the MOF / COF composite material with in-situ embedding of different metal clusters in the present invention;

[0041] Figure 13 Schematic diagram of the furfural aqueous phase hydrogenation performance of the MOF / COF composite material with in-situ embedding of different metal clusters in the present invention. DETAILED DESCRIPTION

[0042] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0043] It is to be noted that when an element is referred to as being "fixed" or "disposed" on another element, it can be directly on the other element or indirectly on the other element with intervening elements present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or indirectly connected to the other element with intervening elements present.

[0044] In addition, the terms "first", "second", "third", etc. are used herein only to describe different instances, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined as "first", "second", etc. can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "a plurality of" is two or more, unless otherwise specifically limited. The meaning of "several" is one or more, unless otherwise specifically limited.

[0045] Biomass derivatives can be converted into high-value chemicals and fuels through hydrogenation reactions, which can greatly increase human demand for materials. Inspired by this, solar water splitting for hydrogen production and biomass hydrogenation conversion can be coupled in series, which is expected to achieve efficient solar conversion into new energy and chemicals. However, the integration of this series of reactions puts higher requirements on the design and preparation of multifunctional catalytic materials. In recent years, representative research has designed a small number of multifunctional catalysts, which have made great progress in the light-thermal catalytic water splitting for hydrogen production and biomass high-value conversion. Different light-catalytic active functional catalysts, such as metal-free semiconductor polymers, photoactive metal-organic framework materials (MOF), covalent organic frameworks (COF), and multi-component composite catalysts, have been widely studied in the photocatalytic water splitting for hydrogen production and catalytic hydrogenation of furfural. However, due to the easy detachment of active components from the catalytic system, and the inability to maximize the utility of functional catalysts, these single strategies are difficult to fundamentally solve the technical problems of low catalytic activity and poor selectivity of target products.

[0046] To solve the above technical problems, in a first aspect, the present application provides a preparation method of a MOF / COF composite material based on in-situ embedding of metal clusters, comprising:

[0047] Obtain a metal target material, place the metal target material in 1,4-dioxane, and irradiate the metal target material with a laser beam under ultrasonic assistance to obtain a metal cluster solution containing metal particles;

[0048] Add a metal salt and an organic ligand to N,N-dimethylformamide, mix uniformly, then add an aqueous glacial acetic acid solution, and react at a temperature of 100-130℃ for 12-24 hours to obtain a MOF material;

[0049] The MOF material and COF monomers are dissolved in a mixed solvent of mesitylene and 1,4-dioxane, and glacial acetic acid is added, and after being frozen and vacuumed, the solvent is reacted for 48-72 hours to obtain the MOF / COF composite material;

[0050] The MOF / COF composite material and mesitylene are added to the metal cluster solution, mixed uniformly, glacial acetic acid is added, and the solvent is reacted for 48-72 hours at a temperature of 100-130 DEG C, and after cooling, the MOF / COF composite material with metal clusters embedded in situ is obtained.

[0051] In the preparation method of the MOF / COF composite material based on in-situ embedded metal clusters of the application, after the metal target is obtained and placed in 1,4-dioxane, the metal target is irradiated by a laser beam to obtain a metal cluster solution containing metal particles, and ultrasonic assistance can avoid the agglomeration of metal particles in 1,4-dioxane; in the process of obtaining the MOF material, metal ions and organic ligands are combined through coordination bonds to form a MOF material with a network structure, and the addition of an ice acetic acid aqueous solution can improve the reaction rate; in the process of obtaining the MOF / COF composite material, an equal volume of mesitylene and 1,4-dioxane with good solubility is used as a mixed solvent to dissolve the MOF material and the COF monomer, and the addition of ice acetic acid can improve the reaction rate and promote the polymerization reaction of the COF monomer, so that the COF monomer is polymerized on the surface or inside of the MOF material to obtain the MOF / COF composite material; in this process, the mixed solution is subjected to freezing and vacuum treatment to remove impurities such as oxygen and water in the mixed solution, thereby improving the purity and efficiency of the reaction; in the process of adding the MOF / COF composite material and mesitylene to the metal cluster solution, the temperature and time of the solvothermal reaction are controlled, so that the metal cluster solution (colloid) can replace 1,4-dioxane in the MOF / COF composite material in-situ to obtain the MOF / COF composite material with in-situ embedded metal clusters; in this process, the addition of ice acetic acid can improve the solvothermal reaction efficiency. Through the above technical solutions of the application, the light capture capability of the MOF / COF material is regulated and improved, the separation dynamics of the charge carriers is improved, and the water decomposition dynamics and the biomass derivative hydrogenation rate are promoted. Specifically, through the above technical solutions of the application, the metal clusters are in-situ embedded in the MOF / COF material, the MOF / COF material anchors the metal clusters to the MOF / COF framework or the interlayer through the pore or interlayer confinement effect, thereby improving the light capture capability of the MOF / COF material and improving the disadvantage of insufficient active sites, further inhibiting the slippage of the COF layer in the MOF / COF material and the escape behavior of the active sites due to insufficient anchoring sites, and effectively promoting the adsorption and activation of water molecules and reactant furfural molecules at the active center, thereby significantly enhancing the electron and hole separation capability and improving the furfural hydrogenation reaction rate. Through the above technical solutions of the application, the technical problems of low catalytic activity and poor selectivity of target products of the existing functional catalyst with photocatalytic activity are solved.

[0052] As a possible implementation, in the preparation method of the MOF / COF composite material based on in-situ embedded metal clusters of the application, the metal target includes one or more of a platinum target, a copper target, a cobalt target, and a nickel target; and / or, the metal target is a metal wafer.

[0053] In the preparation method of the MOF / COF composite material based on in-situ embedding of metal clusters, different types of metal targets can be selected to prepare MOF / COF composite materials with different catalytic properties or catalytic purposes. During the laser beam irradiation process, the metal target can be a metal disc. It should be noted that the type of metal target can also be selected according to the catalytic active center design principle, and the surface of the metal target can be treated to remove the possible oxidation layer or impurities thereon. The surface treatment can be polishing or cleaning. When the cleaning method is used, the metal target is placed in a cleaning solution and ultrasonically treated for 30 minutes at a frequency of 10 kHz. After cleaning, the metal target is placed in 1,4-dioxane (Diox) for laser beam pretreatment to further remove possible impurities on the surface thereof. The purity of the metal target is 99.999%.

[0054] It should be understood that in the preparation method of the MOF / COF composite material based on in-situ embedding of metal clusters, different types of metal salts and organic ligands can be selected to obtain MOF materials that meet different use conditions. For example, the metal salts include zirconium chloride, iron chloride, copper nitrate hydrate, and titanium acid isopropyl, and the organic ligands include 2-amino terephthalic acid, 2,5-diamino terephthalic acid, and 2-hydroxy terephthalic acid. In another example, the metal salts can be zirconium chloride, iron chloride, copper nitrate hydrate, and titanium acid isopropyl, and the organic ligands can be 2-amino terephthalic acid, 2,5-diamino terephthalic acid, and 2-hydroxy terephthalic acid.

[0055] It should also be understood that in the preparation method of the MOF / COF composite material based on in-situ embedding of metal clusters, different types of COF monomers can be selected to obtain COF materials that meet different use conditions. In order to make the prepared composite material have good catalytic activity and target product selectivity, the mass ratio of the metal cluster solution to the MOF / COF composite material should also be controlled within a reasonable range. For example, the COF monomers include tri-aldehyde-based phloroglucinol and p-phenylenediamine, and the mass ratio of the metal cluster solution to the MOF / COF composite material is 1:(4-6). In another example, the COF monomers can be tri-aldehyde-based phloroglucinol and p-phenylenediamine, and the mass ratio of the metal cluster solution to the MOF / COF composite material is 1:4, 1:5, or 1:6. The metal cluster solution is a colloidal solution, and the content of metal particles in the metal cluster solution can be 0.05-0.5wt%, and in another example, the content of metal particles in the metal cluster solution can be 0.05wt%, 0.1wt%, 0.25wt%, 0.4wt%, or 0.5wt%.

[0056] It should be understood that in the preparation method of the metal cluster in-situ embedded MOF / COF composite material of the present application, in the process of irradiating the metal target with a laser beam, in order to improve the irradiation (or bombardment) efficiency of the laser beam on the metal target and obtain a metal cluster solution with uniformly dispersed metal particles, the type of laser beam and the performance parameters of the laser beam should also be controlled; for example, the laser beam includes an unfocused laser beam, for the performance of the laser beam, the output wavelength of the laser beam can be 1064 nm, the pulse frequency can be 20-40 Hz, the output spot diameter can be 5-10 mm, the energy density of the laser beam irradiation can be 800-1600 mJ / cm 2 , and the irradiation time can be 10-30 min; in another example, the laser beam can be an unfocused laser beam, the pulse frequency can be 20 Hz, 30 Hz or 40 Hz, the output spot diameter can be 5 mm, 8 mm or 10 mm, the energy density of the laser beam irradiation can be 800 mJ / cm 2 , 1300 mJ / cm 2 or 1600 mJ / cm 2 , and the irradiation time can be 10 min, 20 min or 30 min; further, the irradiation of the metal target with a laser beam is carried out under the assistance of ultrasound, which can avoid the agglomeration or aggregation of metal particles produced by the irradiation of the metal target with a laser beam in 1,4-dioxane, affecting the subsequent embedding effect, and in this process, the temperature of 1,4-dioxane can also be controlled to further disperse the metal particles uniformly in 1,4-dioxane; for example, the frequency of the ultrasound can be 20-40 kHz, and the temperature of the 1,4-dioxane can be -20-0°C; in another example, the frequency of the ultrasound can be 20 kHz, 30 kHz or 40 kHz, and the temperature of the 1,4-dioxane can be -20°C, -10°C, -5°C or 0°C.

[0057] It should also be understood that in the preparation method of the MOF / COF composite material based on in-situ embedding of metal clusters of the present invention, in the process of adding metal salts and organic ligands to N,N-dimethylformamide, N,N-dimethylformamide is a solvent for the metal salts and organic ligands, and the addition of glacial acetic acid aqueous solution can improve the preparation efficiency of the MOF material. In order to obtain MOF materials with good performance, the mixing amount or addition amount of N,N-dimethylformamide, metal salt and organic ligand should also be controlled within a reasonable range. For example, the mass ratio of the metal salt to the organic ligand can be 1: (1~3), and the mass ratio of the N,N-dimethylformamide to the metal salt can be 1: (2~6); for another example, the mass ratio of the metal salt to the organic ligand can be 1: 1, 1: 2 or 1: 3, and the mass ratio of the N,N-dimethylformamide to the metal salt can be 1: 2, 1: 4 or 1: 6; in the process of adding glacial acetic acid aqueous solution to improve the preparation efficiency of MOF materials, for example, the mass ratio of glacial acetic acid to water in the glacial acetic acid aqueous solution is 1: (40~60), and for another example, the mass ratio of glacial acetic acid to water in the glacial acetic acid aqueous solution is 1: 40, 1: 50 or 1: 60.

[0058] It should also be understood that in the preparation method of the MOF / COF composite material based on in-situ embedding of metal clusters of the present invention, the MOF material and the COF monomer are dissolved in a mixed solvent of mesitylene and 1,4-dioxane. In order to obtain a MOF / COF composite material with good performance, the mass ratio of the MOF material to the COF monomer, the addition amount of 1,4-dioxane and mesitylene should also be controlled within a reasonable range. For example, the mass ratio of the MOF material to the COF monomer can be 1: (1~5), the mass ratio of the MOF material to the 1,4-dioxane can be 1: (0.03~0.1), and the volumes of mesitylene and the 1,4-dioxane in the mixed solvent are equal. For another example, the mass ratio of the MOF material to the COF monomer can be 1: 1, 1: 3 or 1: 5, and the mass ratio of the MOF material to the 1,4-dioxane can be 1: 0.03, 1: 0.05 or 1: 0.1.

[0059] In a second aspect, the present invention provides a MOF / COF composite material based on in situ embedding of metal clusters, which is prepared using the above-mentioned method for preparing a MOF / COF composite material based on in situ embedding of metal clusters; in the MOF / COF composite material based on in situ embedding of metal clusters, the mass ratio of MOF material to COF material is 1:(1~5), and the mass ratio of metal to the MOF material is 1:(200~2000).

[0060] In the case of the above technical solution, the MOF / COF composite material based on in-situ embedded metal clusters is prepared by the above preparation method of the MOF / COF composite material based on in-situ embedded metal clusters. In the preparation method, the metal target material is placed in 1,4-dioxane after being obtained, and the metal target material is irradiated by a laser beam to obtain a metal cluster solution containing metal particles. Under the assistance of ultrasonic waves, the metal particles can be prevented from agglomerating in the 1,4-dioxane. In the process of obtaining the MOF material, the metal ions and the organic ligand are combined by a coordination bond to form a MOF material with a network structure. The addition of an ice acetic acid aqueous solution can improve the reaction rate. In the process of obtaining the MOF / COF composite material, an equal volume of mesitylene and 1,4-dioxane with good solubility is used as a mixed solvent to dissolve the MOF material and the COF monomer. The addition of ice acetic acid can improve the reaction rate and promote the polymerization reaction of the COF monomer, so that the COF monomer is polymerized on the surface or inside of the MOF material to obtain the MOF / COF composite material. In this process, the mixed solution is subjected to freezing and vacuumizing treatment to remove impurities such as oxygen and water in the mixed solution, thereby improving the purity and efficiency of the reaction. In the process of adding the MOF / COF composite material and mesitylene to the metal cluster solution, the temperature and time of the solvothermal reaction are controlled, so that the metal cluster solution (colloid) can replace the 1,4-dioxane in the MOF / COF composite material in-situ to obtain the MOF / COF composite material based on in-situ embedded metal clusters. In this process, the addition of ice acetic acid can improve the solvothermal reaction efficiency. The preparation method embeds the metal clusters in the MOF / COF in-situ. The MOF / COF material limits the metal clusters to the MOF / COF framework or the interlayer by the pore or interlayer confinement effect, thereby improving the light capture capability of the MOF / COF material and overcoming the disadvantage of insufficient active sites. Further, the slippage of the COF layer in the MOF / COF material and the escape behavior of the active sites due to insufficient anchoring sites can be inhibited, and the adsorption and activation of water molecules and reactant furfural molecules at the active center are effectively promoted, thereby significantly enhancing the electron and hole separation capability and improving the furfural hydrogenation reaction rate. For example, in the MOF / COF composite material based on in-situ embedded metal clusters, the mass ratio of the MOF material to the COF material can be 1:1, 1:3 or 1:5, and the mass ratio of the metal to the MOF material can be 1:200, 1:800, 1:1000, 1:1500 or 1:2000.

[0061] In a third aspect, the application provides the application of the above MOF / COF composite material based on in-situ embedded metal clusters in photocatalytic water splitting and furfural aqueous-phase hydrogenation reactions.

[0062] For better understanding of the present application, the content of the present application is further illustrated below in combination with specific examples, but the content of the present application is not limited to the following examples only.

[0063] The raw materials used in the following examples are all commercially available raw materials unless otherwise specified. Example 1

[0064] The present embodiment provides a preparation method of a MOF / COF composite material based on in-situ embedding of metal clusters, comprising:

[0065] S100, obtaining a platinum (Pt) metal disc, placing the metal disc in 1,4-dioxane, controlling the temperature of the 1,4-dioxane to be-20℃, under the assistance of ultrasonic with a frequency of 20 kHz, using a non-focused laser beam to irradiate the metal disc, to obtain a metal cluster solution containing platinum metal particles; the content of platinum in the metal cluster solution is 0.1wt%; the diameter of the metal disc is 15mm, and the thickness is 5mm;

[0066] Wherein, the output wavelength of the laser beam is 1064nm, the pulse frequency is 20Hz, the output spot diameter is 5mm, the energy density of the laser beam irradiation is 800mJ / cm 2 , and the irradiation time is 10min;

[0067] S200, adding zirconium chloride and 2-amino terephthalic acid in 15mL of N,N-dimethylformamide, uniformly mixing after ultrasonic dispersion for 20 minutes, adding 3mL of ice acetic acid aqueous solution, and reacting at a temperature of 100℃ for 24 hours to obtain a MOF material UiO-66-NH2;

[0068] Wherein, the mass ratio of N,N-dimethylformamide to zirconium chloride is 1:2, the mass ratio of zirconium chloride to 2-amino terephthalic acid is 1:1, the mass ratio of glacial acetic acid to water in the ice acetic acid aqueous solution is 1:40, and the frequency of ultrasonic is 20kHz;

[0069] S300, dissolving 5g of the MOF material UiO-66-NH2 and 5g of the COF monomer in the mixed solvent of mesitylene and 1,4-dioxane in step S200, and adding 50mL of ice acetic acid, after freezing and vacuumizing, solvent thermal reaction for 72 hours to obtain a MOF / COF composite material;

[0070] The mass ratio of the MOF material UiO-66-NH2 to 1,4-dioxane is 1:0.03, and the mixed solvent is an equal volume of mesitylene and 1,4-dioxane; the COF monomer is triformylphloroglucinol (TP) and p-phenylenediamine (Pa-1), and in the MOF / COF composite material, the MOF material is UiO-66-NH2, and the COF material is TP-Pa-1-COF;

[0071] S400, the MOF / COF composite material in step S300 and mesitylene are added into the metal cluster solution of 150 mL in step S100, and after being uniformly mixed, 0.05 mL of glacial acetic acid is added, and the solvent is heated at a temperature of 100 DEG C for 72 hours, and after being cooled to room temperature (25 DEG C), a MOF / COF composite material in which platinum metal clusters are embedded in situ is obtained; wherein the mass ratio of the metal cluster solution to the MOF / COF composite material is 1:4, and the volume of the mesitylene is equal to that of the metal cluster solution. Example 2

[0072] The embodiment provides a preparation method of a MOF / COF composite material based on metal cluster in-situ embedding, comprising:

[0073] S100, a platinum (Pt) metal disc is obtained, the metal disc is placed in 1,4-dioxane, the temperature of the 1,4-dioxane is controlled to be 0 DEG C, a non-focused laser beam is used to irradiate the metal disc under the assistance of ultrasonic waves with a frequency of 40 kHz, and a metal cluster solution containing platinum metal particles is obtained; the content of platinum in the metal cluster solution is 0.2 wt%; the diameter of the metal disc is 20 mm, and the thickness is 5 mm;

[0074] The output wavelength of the laser beam is 1064 nm, the pulse frequency is 40 Hz, the output spot diameter of the laser beam is 10 mm, the energy density of the laser beam irradiation is 1600 mJ / cm 2 , and the irradiation time is 30 min;

[0075] S200, zirconium chloride and 2-amino terephthalic acid are added into 30 mL of N,N-dimethylformamide, and after being uniformly mixed by ultrasonic dispersion for 20 min, 1 mL of an ice acetic acid aqueous solution is added, and the reaction is carried out at a temperature of 120 DEG C for 18 hours, and a MOF material UiO-66-NH2 is obtained;

[0076] The mass ratio of N,N-dimethylformamide to zirconium chloride is 1:6, the mass ratio of zirconium chloride to 2-amino terephthalic acid is 1:3, the mass ratio of glacial acetic acid to water in the ice acetic acid aqueous solution is 1:60, and the frequency of ultrasonic waves is 20 kHz;

[0077] S300, 5 g of MOF material UiO-66-NH2 in step S200 is dissolved in a mixed solvent of mesitylene and 1,4-dioxane, 20 g of COF monomer is added, 50 mL of glacial acetic acid is added, after being frozen and vacuumized, the solvothermal reaction is carried out for 48 hours to obtain the MOF / COF composite material;

[0078] The mass ratio of the MOF material UiO-66-NH2 to 1,4-dioxane is 1:0.1, the mixed solvent is equal volume of mesitylene and 1,4-dioxane, the COF monomer is tri-aldehyde-based resorcinol (TP) and p-phenylenediamine (Pa-1), and in the MOF / COF composite material, the MOF material is UiO-66-NH2 and the COF material is TP-Pa-1-COF;

[0079] S400, 150 mL of the metal cluster solution in step S100 is added with the MOF / COF composite material in step S300 and mesitylene, after being mixed uniformly, 50 mL of glacial acetic acid is added, and the solvothermal reaction is carried out at a temperature of 100℃ for 48 hours, and after being cooled to room temperature (25℃), the MOF / COF composite material with platinum metal clusters embedded in situ is obtained; wherein the mass ratio of the metal cluster solution to the MOF / COF composite material is 1:6, and the volume of the mesitylene is equal to that of the metal cluster solution. Example 3

[0080] The embodiment provides a preparation method of a MOF / COF composite material based on metal cluster in-situ embedding, comprising:

[0081] S100, a platinum (Pt) metal disc is obtained, the metal disc is placed in 1,4-dioxane, the temperature of the 1,4-dioxane is controlled to be-10℃, a non-focused laser beam is irradiated on the metal disc under the assistance of ultrasonic waves with a frequency of 30 kHz to obtain a metal cluster solution containing platinum metal particles; the content of platinum in the metal cluster solution is 0.3 wt%, the diameter of the metal disc is 20 mm, and the thickness of the metal disc is 10 mm;

[0082] The output wavelength of the laser beam is 1064 nm, the pulse frequency is 30 Hz, the output spot diameter of the laser beam is 8 mm, the energy density of the laser beam irradiation is 1300 mJ / cm 2 , and the irradiation time is 20 min;

[0083] S200, zirconium chloride and 2-amino terephthalic acid are added in 20 mL of N,N-dimethylformamide, the mixture is uniformly dispersed by ultrasonic for 20 minutes, 2 mL of an aqueous solution of glacial acetic acid is added, and the reaction is carried out at a temperature of 130℃ for 12 hours to obtain the MOF material UiO-66-NH2;

[0084] The mass ratio of N,N-dimethylformamide to zirconium chloride is 1:4, the mass ratio of zirconium chloride to 2-amino terephthalic acid is 1:2, the mass ratio of glacial acetic acid to water in the aqueous solution of glacial acetic acid is 1:50, and the frequency of ultrasonic is 20 kHz.

[0085] S300, 5g of MOF material UiO-66-NH2 in step S200 is dissolved in a mixed solvent of mesitylene and 1,4-dioxane, 50mL of glacial acetic acid is added, and after being frozen and vacuumed, the solvothermal reaction is carried out for 60 hours to obtain a MOF / COF composite material;

[0086] The mass ratio of MOF material UiO-66-NH2 to 1,4-dioxane is 1:0.05, the mixed solvent is equal volume of mesitylene and 1,4-dioxane, the COF monomer is tri-aldehyde-based phloroglucinol (TP) and p-phenylenediamine (Pa-1), and in the MOF / COF composite material, the MOF material is UiO-66-NH2 and the COF material is TP-Pa-1-COF;

[0087] S400, 150mL of the metal cluster solution in step S100 is added with the MOF / COF composite material in step S300 and mesitylene, and after being mixed uniformly, 50mL of glacial acetic acid is added, and the solvothermal reaction is carried out at a temperature of 100℃ for 60 hours, and after being cooled to room temperature (25℃), a MOF / COF composite material with platinum metal clusters embedded in situ is obtained; wherein the mass ratio of the metal cluster solution to the MOF / COF composite material is 1:1.5, and the volume of mesitylene is equal to that of the metal cluster solution. Example 4

[0088] The embodiment provides a preparation method of a MOF / COF composite material based on metal cluster in-situ embedding, comprising:

[0089] S100, a copper (Cu) metal wafer is obtained, the metal wafer is placed in 1,4-dioxane, the temperature of 1,4-dioxane is controlled to be-10℃, a non-focused laser beam is irradiated on the metal wafer under the assistance of ultrasonic with a frequency of 30kHz to obtain a metal cluster solution containing copper metal particles; the content of copper in the metal cluster solution is 0.3wt%; the diameter of the metal wafer is 15mm, and the thickness is 5mm;

[0090] The output wavelength of the laser beam is 1064nm, the pulse frequency is 30Hz, the output spot diameter is 8mm, the energy density of the laser beam irradiation is 1300mJ / cm 2 , and the irradiation time is 20min;

[0091] S200, adding zirconium chloride and 2-amino terephthalic acid in 15 mL of N,N-dimethylformamide, uniformly mixing by ultrasonic dispersion for 20 minutes, adding 1 mL of glacial acetic acid aqueous solution, and reacting at a temperature of 130 DEG C for 12 hours to obtain a MOF material UiO-66-NH2;

[0092] The mass ratio of N,N-dimethylformamide to zirconium chloride is 1:4, the mass ratio of zirconium chloride to 2-amino terephthalic acid is 1:2, the mass ratio of glacial acetic acid to water in the glacial acetic acid aqueous solution is 1:50, and the frequency of ultrasonic is 20 kHz.

[0093] S300, dissolving 5 g of the MOF material UiO-66-NH2 in step S200 and 7.5 g of COF monomers in a mixed solvent of mesitylene and 1,4-dioxane, adding 50 mL of glacial acetic acid, and performing a solvothermal reaction for 60 hours after freezing and vacuumizing to obtain a MOF / COF composite material.

[0094] The mass ratio of the MOF material UiO-66-NH2 to 1,4-dioxane is 1:0.05, the mixed solvent is an equal volume of mesitylene and 1,4-dioxane, the COF monomers are triformylphloroglucinol (TP) and p-phenylenediamine (Pa-1), and in the MOF / COF composite material, the MOF material is UiO-66-NH2 and the COF material is TP-Pa-1-COF.

[0095] S400, adding the MOF / COF composite material in step S300 and mesitylene to 150 mL of the metal cluster solution in step S100, uniformly mixing, adding 50 mL of glacial acetic acid, and performing a solvothermal reaction for 60 hours at a temperature of 100 DEG C to obtain a MOF / COF composite material with copper metal clusters embedded in situ after cooling to room temperature (25 DEG C). The mass ratio of the metal cluster solution to the MOF / COF composite material is 1:1.5, and the volume of mesitylene is equal to that of the metal cluster solution.

[0096] Through the above embodiments 1 to 4, different MOF / COF composite materials with metal clusters embedded in situ are prepared. Figures 1 to 13 From the above, Figure 1 It can be seen that the MOF / COF composite material (composite catalyst) has excellent ability in photocatalytic water splitting for hydrogen production and high-value utilization of furfural hydrogenation; from the above, Figure 2 It can be seen that the prepared MOF material UiO-66-NH2 is a spherical particle with a size of about 200 nm; from the above, Figure 3 It can be seen that the prepared COF material TP-Pa-1-COF has a two-dimensional dendritic nanostructure; from the above, Figure 4It can be seen that the size of the Pt cluster in the prepared Pt metal cluster in-situ embedded MOF / COF composite material (Pt@MOF / COF composite material) is 1-2 nm; from Figure 5 It can be seen that in the prepared Pt@MOF / COF composite material, 3-5 nm larger size Pt nanoparticles are distributed between the MOF / COF layers, and the Pt nanocluster grows due to the weak anchoring force of the MOF material; from Figure 6 It can be seen that in the prepared MOF / COF (1:1) composite material, the COF nanowire is wound around the surface of the MOF nanoparticle to form a stable two-dimensional / three-dimensional mixed-dimensional structure; Figure 7 It is a physical picture of MOF / COF (1:1), and the color is blood red; from Figure 8 It can be seen that in the prepared MOF / COF (1:4) composite material, the MOF nanoparticle is embedded in the dendritic COF; Figure 9 It is a physical picture of MOF / COF (1:4), and the color is blood red; from Figure 10 It can be seen that in the prepared MOF / COF (2:3) composite material, the MOF nanoparticle is embedded in the dendritic COF, which is due to the fact that the COF is more than the MOF component; Figure 11 It is a physical picture of MOF / COF (2:3), and the color is blood red, mainly with the color of COF; from Figure 12 From the performance diagram of the catalyst for photocatalytic water splitting to produce hydrogen, the hydrogen production rate of the Pt0.3@MOF / COF (1:1) catalyst is as high as 101.1 mmol g -1 h -1 , which is the best performance catalyst among similar materials; from Figure 13 From the performance diagram of different catalysts for the photocatalytic hydrogenation of furfural, as the Pt loading increases from 0.05wt% to 0.2wt%, the conversion rate of furfural reaches 100%, and the hydrogenation product is tetrahydrofurfuryl alcohol. However, when the Pt content continues to increase to 0.3wt%, the product of furfural hydrogenation gradually changes to 2-methylfuran, which is due to the fact that the high active density of Pt sites reduces the potential barrier of furfural hydrogenation deoxidation. When the Pt content continues to increase, it is found that byproducts will be produced, because when the Pt content exceeds 0.3wt%, the Pt will aggregate to reduce the activity.

[0097] In summary, the application in-situ embeds metal clusters in MOF / COF by using liquid phase pulse laser technology; the basic process can be: first, select high-purity metal platinum, copper, cobalt, nickel source and 1,4-dioxane (Diox), then directly prepare Pt(Diox), Cu(Diox), Co(Diox), Ni(Diox) metal cluster solution by using extreme condition transient pulse laser irradiation technology, then use the above metal cluster solution as a solvent for synthesizing MOF / COF, and obtain the MOF / COF composite material in-situ embedded with metal clusters by one-pot reaction, and the size and content of metal particles in the metal cluster solution or the MOF / COF composite material are controllable. The application uses the component feeding ratio to prepare the MOF / COF composite material with controllable micro-morphology, and when the content of the MOF material is higher than that of the COF material, the COF material is wound around the MOF material in the form of nanowire to form a COF covering layer; when the content of the MOF material is lower than that of the COF material, the MOF nanoparticles are dispersed on the dendritic COF. Further, by the technical scheme of the application, the metal clusters with electron traps and catalytic active sites are in-situ embedded in MOF / COF with different structures to prepare a metal organic framework bridging covalent organic framework composite catalyst in-situ anchored with metal clusters, which can improve the slow separation kinetics of charge carriers by adjusting the light trapping ability of MOF / COF, and promote the water decomposition kinetics and the biomass derivative hydrogenation rate; further, the MOF / COF limits the metal clusters to the MOF / COF skeleton or interlayer through the channel or interlayer limiting effect, thereby improving the shortcomings of poor MOF light trapping ability and insufficient catalytic active sites, not only inhibiting the COF layer from sliding and the active site from escaping due to insufficient anchoring sites, but also promoting the adsorption-activation of water molecules and reactant furfural molecules in the active center, thereby significantly enhancing the electron-hole separation ability and improving the furfural hydrogenation reaction rate.

[0098] In the description of the above-described embodiments, specific features, structures, materials or characteristics can be combined in any one or more embodiments or examples in a suitable manner.

[0099] The above description is merely specific embodiments of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the present application, which should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A method for preparing a MOF / COF composite material based on in-situ embedding of metal clusters for photocatalytic aqueous hydrogenation of furfural, characterized in that: include: Obtaining a metal target, placing the metal target in 1,4-dioxane, and irradiating the metal target with a laser beam under ultrasound assistance to obtain a metal cluster solution containing metal particles; Add metal salt and organic ligand to N,N-dimethylformamide, mix well, add glacial acetic acid aqueous solution, and react at a temperature of 100-130°C for 12-24 hours to obtain MOF material; The MOF material and COF monomers are dissolved in a mixed solvent of mesitylene and 1,4-dioxane, and glacial acetic acid is added. After freezing and vacuuming, the mixture is subjected to solvent thermal reaction for 48 to 72 hours to obtain a MOF / COF composite material; the COF monomers are trialdehyde phloroglucinol and p-phenylenediamine; The MOF / COF composite material and mesitylene are added to the metal cluster solution, mixed evenly, and then glacial acetic acid is added. The mixture is subjected to solvent thermal reaction at a temperature of 100-130° C. for 48-72 hours. After cooling, a MOF / COF composite material with metal clusters embedded in situ is obtained.

2. The preparation method according to claim 1, characterized in that The metal target comprises one or more of a platinum target, a copper target, a cobalt target and a nickel target; and / or, The metal target material is a metal disc.

3. The preparation method according to claim 2, characterized in that The metal salts include zirconium chloride, ferric chloride, hydrated copper nitrate and tetraisopropyl titanate; and / or, The organic ligands include 2-aminoterephthalic acid, 2,5-diaminoterephthalic acid and 2-hydroxyterephthalic acid.

4. The preparation method according to claim 3, characterized in that In the process of adding the MOF / COF composite material and mesitylene to the metal cluster solution, the mass ratio of the metal cluster solution to the MOF / COF composite material is 1:(4-6), and the volumes of the mesitylene and the metal cluster solution are equal.

5. The preparation method according to claim 4, characterized in that The metal cluster solution is a colloidal solution; and / or, The content of metal particles in the metal cluster solution is 0.05-0.5 wt %.

6. The preparation method according to claim 5, characterized in that In the process of irradiating the metal target material with a laser beam under ultrasound assistance, the laser beam includes an unfocused laser beam; and / or, The laser beam has an output wavelength of 1064 nm, a pulse frequency of 20-40 Hz, an output spot diameter of 5-10 mm, and an energy density of 800-1600 mJ / cm 2 , irradiation time is 10~30min; and / or, The temperature of the 1,4-dioxane is -20-0°C, and the frequency of the ultrasound is 20-40 kHz.

7. The preparation method according to claim 6, characterized in that In the process of adding the metal salt and the organic ligand to N,N-dimethylformamide, the mass ratio of the metal salt to the organic ligand is 1:(1-3), and the mass ratio of the N,N-dimethylformamide to the metal salt is 1:(2-6); and / or, The mass ratio of glacial acetic acid to water in the glacial acetic acid aqueous solution is 1: (40-60).

8. The preparation method according to claim 7, characterized in that The MOF material and the COF monomer are dissolved in a mixed solvent of mesitylene and 1,4-dioxane, wherein the mass ratio of the MOF material to the COF monomer is 1:(1-5), the mass ratio of the MOF material to the 1,4-dioxane is 1:(0.03-0.1), and the volumes of mesitylene and the 1,4-dioxane in the mixed solvent are equal; and / or, In the MOF / COF composite material in which the metal clusters are in situ embedded, the mass ratio of the MOF material to the COF material is 1:(1-5), and the mass ratio of the metal to the MOF material is 1:(200-2000).

9. A MOF / COF composite material based on in-situ embedding of metal clusters, characterized in that: Prepared by the preparation method according to any one of claims 1 to 8; in the MOF / COF composite material based on in-situ embedding of metal clusters, the mass ratio of MOF material to COF material is 1: (1-5), and the mass ratio of metal to the MOF material is 1: (200-2000).

10. Use of the MOF / COF composite material based on in-situ embedding of metal clusters according to claim 9 in the photocatalytic aqueous phase hydrogenation reaction of furfural.

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