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CN-122011311-A - Preparation method of metal nanocluster confined covalent organic framework composite material

CN122011311ACN 122011311 ACN122011311 ACN 122011311ACN-122011311-A

Abstract

The application belongs to the technical field of nano composite materials, and discloses a preparation method of a metal nano cluster confined covalent organic framework composite material, which comprises the steps of firstly adopting nanosecond pulse laser liquid phase to ablate a metal target material, and carrying out secondary laser irradiation on the obtained dispersion liquid at low temperature to prepare a metal nano cluster colloid solution; then, the aldehyde precursor and the amine precursor of the covalent organic framework are added into the colloid solution, and the final composite material is obtained through mixing, standing polymerization reaction, washing and drying. According to the application, an exogenous chemical reducing agent is not required, and synchronous and uniform domain-limited packaging of the metal nanoclusters in the covalent organic framework pore generation process is realized through an in-situ polymerization strategy. The prepared composite material has high dispersibility and high activity of metal clusters, and structural integrity and domain-limited stability of a carrier material, and has good application prospect in the field of heterogeneous catalysis.

Inventors

  • WANG HONGQIANG
  • LI YIFAN
  • Shuang Yazhou
  • JIAN JIE

Assignees

  • 西北工业大学

Dates

Publication Date
20260512
Application Date
20260203

Claims (10)

  1. 1. The preparation method of the metal nanocluster domain-limited covalent organic framework composite material is characterized by comprising the following steps of: S1, bombarding a metal target material placed in a solvent by adopting first nanosecond pulse laser to obtain metal nanocluster mother liquor, and then performing secondary irradiation on the metal nanocluster mother liquor by adopting second nanosecond pulse laser at an ambient temperature of-20-10 ℃ to obtain metal nanocluster colloid solution, wherein the wavelength of the first nanosecond pulse laser is 1064 nm, the flux is 1-2 Jpuls -1 cm -2 , and the flux of the second nanosecond pulse laser is 0.1-2 Jpuls -1 cm -2 ; s2, adding an aldehyde precursor and an amine precursor of the covalent organic framework into the metal nanocluster colloid solution, mixing to form a reaction system, carrying out standing polymerization reaction at 120 ℃, and washing and drying an obtained solid product after the reaction is finished to obtain the metal nanocluster domain-limited covalent organic framework composite material.
  2. 2. The preparation method of claim 1, wherein the first nanosecond pulse laser bombards the metal target for 1-20 min and the second irradiation time for 1-10 min.
  3. 3. The method according to claim 1, wherein the solvent is one selected from the group consisting of water, N-butanol, ethanol, dimethyl sulfoxide, N-dimethylformamide, and dioxane.
  4. 4. The method according to claim 1, wherein the metal element of the metal target is at least one selected from Pt, pd, au, fe, co and Ni.
  5. 5. The method of claim 1, wherein the aldehyde precursor and the amine precursor are used in an amount such that the ratio of the total number of moles of aldehyde groups to the total number of moles of amino groups is 1:1.
  6. 6. The method according to claim 1, wherein the aldehyde precursor is one selected from the group consisting of trialdehyde phloroglucinol, 2-hydroxy-1, 3, 5-benzenetricaldehyde and 2, 4-dihydroxy-1, 3, 5-benzenetricaldehyde.
  7. 7. The method according to claim 1, wherein, the amine precursor is selected from the group consisting of p-phenylenediamine, o-phenylenediamine, m-phenylenediamine, o-toluenediamine 2, 5-diaminobenzonitrile, 2, 5-diaminop-benzonitrile, 2-fluoro-1, 4-phenylenediamine, 2-chloro-1, 4-p-phenylenediamine, 2-bromo-1, 4-diaminobenzene, 2-iodo-1, 4-phenylenediamine, 2, 5-dimethyl-1, 4-phenylenediamine, 2-chloro-5-methyl-1, 4-phenylenediamine, 2, 5-dichlorophenylphenylenediamine, 2, 5-difluorop-phenylenediamine, 2, 5-dibromop-phenylenediamine, 2, 5-diaminobenzene-1, 4-diol, 1, 4-diamino-2, 5-divinylbenzene 2, 6-Diynyl-p-phenylenediamine, 3, 4-difluoroo-phenylenediamine, 2, 3-diaminofluorobenzene, 5-bromo-3-fluoro-1, 2-phenylenediamine, 1, 2-diamino-3, 5-difluorobenzene, 4-bromo-3-fluoro-1, 2-phenylenediamine, 3,4,5, 6-tetrafluorobenzene-1, 2-diamine, 3,4, 5-trifluoro-1, 2-diaminobenzene, 4-chloro-6-fluorophthalenediamine, 5-chloro-3-methyl-1, 2-phenylenediamine, 5-bromo-3, 4-dimethylbenzene-1, 2-diamine, 4-bromo-3-toluene-1, 2-diamine, 3, 4-dimethylphthalenediamine, 3, 5-dimethyl-1, 2-phenylenediamine, 5-bromo-3-methylbenzene-1, 2-diamine, one of 2, 3-diaminotoluene, 2, 4-diaminofluorobenzene, 4, 6-difluorobenzene-1, 3-diamine, 2,4, 5-trifluoro-1, 3-phenylenediamine, 4-bromo-6-fluorobenzene-1, 3-diamine, 2-chloro-4-fluoro-1, 3-phenylenediamine, 2-fluoro-4-bromo-1, 3-phenylenediamine, 2, 4-diaminotoluene, 2, 6-diaminotoluene, 2,4, 6-trimethyl-1, 3-phenylenediamine, 2, 4-dimethylbenzene-1, 3-diamine, 2, 4-dimethyl-1, 5-phenylenediamine and 2-methoxybenzene-1, 4-diamine.
  8. 8. The method of claim 1, wherein the metal nanocluster content in the metal nanocluster mother liquid is 0.1 to 50mg/mL.
  9. 9. The preparation method according to claim 1, wherein an acidic catalyst and a boiling point organic solvent are added to the reaction system as a crystallization regulator, wherein the acidic catalyst is an aqueous acetic acid solution with a concentration of 6M, and the high boiling point organic solvent is mesitylene or o-dichlorobenzene.
  10. 10. The metal nanocluster confinement covalent organic framework composite material prepared by the preparation method of any one of claims 1 to 9.

Description

Preparation method of metal nanocluster confined covalent organic framework composite material Technical Field The application belongs to the technical field of nano composite materials, and particularly relates to a preparation method of a metal nanocluster confined covalent organic framework composite material. Background The covalent organic frameworks (Covalent Organic Framework, COFs) are crystalline porous polymers formed by connecting light elements through strong covalent bonds, have definite pore channel structures, high specific surface area and excellent structural adjustability and chemical stability, and have important potential in the fields of heterogeneous catalysis, adsorption separation, energy storage and the like. In particular to a regular nano pore canal, which provides an ideal carrier for loading active catalytic species and realizing space limitation. Metal nanoclusters, which generally refer to aggregates of metal atoms having a size of less than 2 nanometers, often exhibit superior activity in heterogeneous catalysis over conventional nanoparticles due to their extremely high atomic utilization, unique electronic structure, and abundant active sites. However, the surface energy of the metal nanocluster is extremely high, migration agglomeration is extremely easy to occur in the preparation and application processes, the activity is reduced and even deactivated, and the practical application is restricted. The metal nanocluster is stably packaged in the pore canal of the COFs, and the rigid pore wall of the COFs is used for physically limiting the pore canal, so that the metal nanocluster is an effective strategy for inhibiting agglomeration and improving the catalytic stability and recyclability of the metal nanocluster. Currently, the main method for preparing metal species/COFs composite materials is a post-adsorption-reduction strategy, namely, firstly synthesizing complete COFs crystals, then impregnating and adsorbing metal precursors (usually metal salts) in pore channels of the COFs, and finally converting metal ions into zero-valent metal nano particles through chemical reduction or thermal reduction and other methods. However, chemical reducing agents (such as sodium borohydride, hydrazine hydrate and the like) which are introduced later probably damage chemical bonds (such as imine bonds) of a COFs framework to influence crystallinity and structural integrity of the COFs framework, secondly, the distribution control of metal precursors in pore channels is limited in an impregnation process, metal atoms are easy to migrate and aggregate and grow outside the pore channels or at pore openings in the subsequent reduction process, the obtained metal particles are nonuniform in size and discrete in distribution, uniform and specific site limiting of metal clusters in the pore channels of the COFs bulk phase is difficult to realize, and furthermore, the method is complicated in steps and poor in controllability of metal loading capacity and cluster size. Therefore, the art needs to develop a preparation method capable of realizing uniform and stable confinement of the metal nanocluster in the COFs pore canal without damaging the COFs skeleton structure. Disclosure of Invention Aiming at the defects that the prior art relies on a chemical reducing agent, the metal is unevenly distributed and the COFs framework is easy to damage, the application provides a preparation method of a metal nanocluster domain-limited covalent organic framework composite material, and the metal nanocluster colloid solution prepared by laser is directly mixed with a COFs precursor and is subjected to in-situ polymerization, so that the metal clusters are synchronously and uniformly packaged in the COFs pore channel generation process, thereby avoiding the use of an exogenous reducing agent, and obtaining the composite material with highly dispersed metal and complete structure. In order to achieve the technical purpose, the application adopts the following technical scheme: In one aspect of the application, a method for preparing a metal nanocluster confinement covalent organic framework composite material is provided, comprising the steps of: s1, preparing a metal nanocluster colloid solution, namely bombarding a metal target material placed in a solvent by adopting first nanosecond pulse laser to obtain a metal nanocluster mother solution, and then performing secondary irradiation on the metal nanocluster mother solution by adopting second nanosecond pulse laser at an ambient temperature of-20-10 ℃ to obtain the metal nanocluster colloid solution, wherein the wavelength of the first nanosecond pulse laser is 1064 nm, the flux is 1-2 Jpulse -1cm-2, and the flux of the second nanosecond pulse laser is 0.1-2 Jpulse -1cm-2; S2, preparing an in-situ confined composite material, namely adding an aldehyde precursor and an amine precursor of a covalent organic framework into the metal nanocluster colloid solu