CN-116903811-B - Grade Kong Xiji covalent organic framework material and preparation method and application thereof

CN116903811BCN 116903811 BCN116903811 BCN 116903811BCN-116903811-B

Abstract

The invention relates to the technical field of covalent organic framework materials, in particular to a grade Kong Xiji covalent organic framework material and a preparation method and application thereof. Comprises preparing microsphere solid with close-packed structure, adding ligand of covalent organic framework, controlling reaction conditions to obtain microsphere solid-covalent organic framework compound, removing microsphere solid in the compound to form holes, and obtaining covalent organic framework material with grade Kong Xiji. The covalent organic framework material itself has nanoscale pore channels, then close-packed microsphere solids are introduced, the ligand of the covalent organic framework is divided into smallest covalent organic framework ligands, and the smallest covalent organic framework ligands are more beneficial to forming grade holes, the microsphere solids in the microsphere solids-covalent organic framework composite occupy most of the space, a large number of hollows are left after the microsphere solids are removed, mesopores are formed at the joint of macropores and micropores, and finally the alkenyl covalent organic framework material with the grade hole structure is obtained.

Inventors

ZHANG BING
BU RAN
LU YINGYING
LI DI

Assignees

浙江大学杭州国际科创中心

Dates

Publication Date: 20260505
Application Date: 20230718

Claims (10)

1. A method of preparing a class Kong Xiji covalent organic framework material, comprising: centrifugal sedimentation is adopted to prepare microsphere solids with close-packed structures; Adding a ligand of a covalent organic framework and a catalyst into a reaction container with the microsphere solid, sealing the reaction container and carrying out vacuum treatment, wherein the ligand of the covalent organic framework is provided with micropores, and the size of the microsphere is larger than that of the micropores, and the ligand of the covalent organic framework is 2,4, 6-trimethyl-1, 3, 5-triazine and terephthalaldehyde; preheating the reaction vessel subjected to vacuum treatment, then continuously heating, wherein the preheating enables the ligand of the covalent organic framework to form a molten state and to be immersed into the gaps of the microsphere solids, and then continuously heating enables the ligand of the covalent organic framework to gradually polymerize and crystallize, so as to obtain a microsphere solid-covalent organic framework compound; Adding an etchant into the microsphere solid-covalent organic framework composite, removing the microsphere solid in the microsphere solid-covalent organic framework composite and forming pores to obtain an alkenyl covalent organic framework material with a hierarchical pore structure, wherein the step of preparing the microsphere solid with a close-packed structure comprises the steps of uniformly dispersing microspheres with the same order of magnitude size in a first solvent to obtain microsphere suspension, carrying out centrifugal sedimentation on the microsphere suspension, removing redundant first solvent after centrifugal sedimentation to obtain a dry microsphere solid with a close-packed structure, wherein the particle size range of the microspheres is 100nm-1000nm, and the microspheres are silica microspheres.
2. A method of preparing a grade Kong Xiji covalent organic framework material as described in claim 1 wherein the first solvent comprises one of methanol, ethanol, acetone, and tetrahydrofuran.
3. A method of preparing a class Kong Xiji of covalent organic framework materials as described in claim 1 wherein said catalyst comprises one of benzoic anhydride or benzoic acid.
4. A method of preparing a grade Kong Xiji covalent organic framework material as claimed in claim 1 wherein the reaction vessel is preheated by an oven at a temperature in the range 50 ℃ to 130 ℃ for a time in the range 5min to 30min and continuously heated at a temperature in the range 160 ℃ to 220 ℃ for a time in the range 2 days to 7 days.
5. The method of claim 1, wherein the etchant comprises one of hydrofluoric acid, an ammonium fluoride solution, and a strong base solution, and wherein the strong base solution comprises one of an aqueous potassium hydroxide solution, an aqueous sodium hydroxide solution, and an aqueous lithium hydroxide solution.
6. The method of preparing a grade Kong Xiji covalent organic framework material of claim 1, further comprising grinding the microsphere solid-covalent organic framework composite into a covalent organic framework composite powder and removing the microsphere solid in the microsphere solid-covalent organic framework composite powder with an etchant to form pores.
7. The method of claim 1, further comprising a second washing and a second drying of the crystallized covalent organic framework ligand prior to obtaining the microsphere solid-covalent organic framework composite, wherein the second washing comprises one of methanol and ethanol, the second washing comprises one of Soxhlet extraction washing and filtration washing, and the second drying temperature is in the range of 60 ℃ to 120 ℃.
8. A method of preparing a class Kong Xiji covalent organic framework material of claim 1, wherein said class of pores comprises macropores, mesopores and micropores, wherein said macropores range from 100nm to 500nm, said mesopores range from 2nm to 3nm, and said micropores range from 1nm to 2nm.
9. Grade Kong Xiji covalent organic framework material, characterized in that it is obtainable by a preparation method according to any one of claims 1 to 8.
10. Use of the grade Kong Xiji covalent organic framework material of claim 9 in a photocatalytic hydrogen evolution reaction.

Description

Grade Kong Xiji covalent organic framework material and preparation method and application thereof Technical Field The invention relates to the technical field of covalent organic framework materials, in particular to a grade Kong Xiji covalent organic framework material and a preparation method and application thereof. Background Covalent organic framework materials (COFs) are a new class of crystalline porous materials with well-defined and highly programmable structures, which have low density, high surface area and easy modification characteristics, and have therefore gained extensive attention and research in recent years. Because of their highly customizable structure, covalent organic frameworks have a range of potential applications in chemistry and chemical engineering, including advanced uses for electro-optical response, catalysis, adsorption, filtration, separation, and drug delivery. While covalent organic framework materials are a particular porous material, the topological features of covalent organic framework materials, particularly the pore size in each dimension and the uniformity of these pores, are key factors in determining the covalent organic framework materials in specific applications, rational development of highly stable covalent organic framework materials with low cost and hierarchical pore structures remains a very serious challenge. Disclosure of Invention To achieve the above object, the present invention provides a method for preparing a grade Kong Xiji covalent organic framework material, comprising: Preparing microsphere solid with a close-packed structure; Adding a ligand of a covalent organic framework and a catalyst into a reaction container with the microsphere solid, sealing the reaction container and carrying out vacuum treatment, wherein the ligand of the covalent organic framework has micropores, and the size of the microsphere is larger than that of the micropores; preheating the reaction vessel subjected to vacuum treatment, then continuously heating, wherein the preheating enables the ligand of the covalent organic framework to form a molten state and to be immersed into the gaps of the microsphere solids, and then continuously heating enables the ligand of the covalent organic framework to gradually polymerize and crystallize, so as to obtain a microsphere solid-covalent organic framework compound; And adding an etchant into the microsphere solid-covalent organic framework compound, removing the microsphere solid in the microsphere solid-covalent organic framework compound, and forming pores to obtain the alkenyl covalent organic framework material with the hierarchical pore structure. Optionally, the step of preparing the microsphere solid having a close-packed structure comprises: uniformly dispersing microspheres with the same order of magnitude in a first solvent to obtain microsphere suspension; carrying out centrifugal sedimentation on the microsphere suspension; And removing the redundant first solvent after centrifugal sedimentation to obtain the dry close-packed structure microsphere solid. Optionally, the first solvent includes one of methanol, ethanol, acetone, and tetrahydrofuran. Optionally, the particle size of the microsphere is 100nm-1000nm, and the microsphere comprises one of titanium dioxide microsphere, silicon microsphere and silicon dioxide microsphere. Optionally, the ligand of the covalent organic framework comprises one or more of 2,4, 6-trimethyl-1, 3, 5-triazine, 2,4, 6-trimethyl pyridine, 2,4, 6-trimethyl pyrimidine, 1,3, 5-tribenzyl nitrile, terephthalaldehyde, biphenyl dicarboxaldehyde, dipyridyl dicarboxaldehyde and p-terphenyl dicarboxaldehyde, and the catalyst comprises one of benzoic anhydride or benzoic acid. Optionally, the reaction vessel is preheated and continuously heated by an oven, wherein the preheating temperature is 50-130 ℃, the preheating time is 5-30 min, the continuously heating temperature is 160-220 ℃, and the continuously heating time is 2-7 days. Optionally, the etchant includes one of hydrofluoric acid, ammonium fluoride solution and strong alkali solution, and the strong alkali solution includes one of potassium hydroxide aqueous solution, sodium hydroxide aqueous solution and lithium hydroxide aqueous solution. Optionally, the method further comprises grinding the microsphere solid-covalent organic framework composite into covalent organic framework composite powder, and removing the microsphere solid in the microsphere solid-covalent organic framework composite powder by using an etching agent to form pores. Optionally, before the microsphere solid-covalent organic framework compound is obtained, a second washing and a second drying are further carried out on the crystallized ligand of the covalent organic framework, wherein the second washing agent comprises one of methanol and ethanol, the second washing mode comprises one of Soxhlet extraction washing and filtration washing, and the second drying temp