CN111944159A

CN111944159A - Zinc-based flaky metal organic framework particle material and preparation method thereof

Info

Publication number: CN111944159A
Application number: CN202010729831.8A
Authority: CN
Inventors: 薛立新; 李士洋
Original assignee: Zhejiang University of Technology ZJUT
Current assignee: Zhejiang University of Technology ZJUT
Priority date: 2020-07-27
Filing date: 2020-07-27
Publication date: 2020-11-17

Abstract

The invention discloses a zinc-based flaky metal organic framework particle material and a preparation method thereof, which are carried out according to the following steps: preparing imidazole ligand, zinc nitrate and water into solutions according to a certain molar ratio, and respectively naming the solutions as A, B solutions; and dropwise adding the solution B into the solution A, stirring for a certain time at a certain temperature, separating a product, washing and drying in vacuum to obtain the zinc-based sheet metal organic framework material. The method of the invention does not involve and use any organic solvent, has no pollution and interference of other organic solvents, has simple process, simple and convenient operation, and easy synthesis method and preparation conditions.

Description

Zinc-based flaky metal organic framework particle material and preparation method thereof

Technical Field

The invention relates to a zinc-based flaky metal organic framework particle material and a preparation method thereof.

Background

Metal-Organic Frameworks (MOFs), which are Organic-inorganic hybrid materials with intramolecular pores formed by self-assembly of Organic ligands and Metal ions or clusters through coordination bonds. Metal Organic Frameworks (MOFs) are an attractive crystalline porous material and have attracted considerable attention in academia and industry. MOFs have been extensively studied for their unique properties, such as large surface area, high pore volume and open metal sites, as well as for potential applications in various fields. MOFs have many advantages over inorganic porous materials such as zeolites or metal phosphate-based materials. Structural diversity is one of the most important advantages of MOFs. MOFs can also be extended to several similar (isomorphous or isomorphic) frameworks that are synthesized from different metal components and the same linker. A series of MOFs named homoreticular MOFs are obtained by coordinating a series of ligands (of different lengths) having the same metal component, wherein the pore size/shape of the respective MOF depends on the length of the ligand. In addition, MOFs can also be modified to impart various functions to ligands and metal centers. The patent refers to the field of 'catalysts'. In which organic imidazolate is cross-linked to a transition metal to form a tetrahedral framework. Many different ZIF structures can be formed by simply adjusting the cross-linking-cross-linking interaction.

The synthesis methods usually adopted by MOFs are not significantly different from the conventional inorganic synthesis methods, and evaporative solvent methods, diffusion methods (which can be subdivided into gas phase diffusion, liquid phase diffusion, gel diffusion, and the like), hydrothermal or solvothermal methods, ultrasonic and microwave methods, and the like can be used for MOFs synthesis. Of these methods, hydrothermal or solvothermal methods are most important, and most MOFs are synthesized by hydrothermal or solvothermal methods. The hydrothermal or solvothermal method belongs to the category of liquid phase chemical methods, and refers to a chemical synthesis method performed in a sealed pressure vessel under high temperature and high pressure conditions using water as a solvent. However, the final MOF particles obtained by any method are hexagonal blocks or spheres, and the method synthesizes the flaky nano particles, which has important research and practical value significance for the research of NOF morphology, and the improvement of the membrane structure and the stability of the membrane structure by adding the nano particles into the membrane as a water channel control additive.

Disclosure of Invention

The invention aims to synthesize the zinc-based flaky metal organic framework particle material by a simple, effective and less-pollution method and a preparation method thereof.

The technical scheme adopted by the invention is as follows: a preparation method of a zinc-based flaky metal organic framework particle material is characterized by comprising the following steps: the method comprises the following steps:

1) dissolving imidazole ligand into deionized water, wherein the molar concentration of the imidazole ligand is 0.24-0.48 mol/L, and ultrasonically dissolving and uniformly stirring the imidazole ligand to obtain solution A; dissolving zinc nitrate into deionized water, wherein the molar concentration of the zinc nitrate is 0.05-0.10 mol/L, ultrasonically dissolving and uniformly stirring to obtain a solution B;

2) respectively taking the two solutions obtained in the step 1), and enabling the molar ratio of zinc ions to imidazole in the two solutions to be 1: 1-10;

placing the solution A in a constant-speed stirring state, placing the solution B in a separating funnel, dropwise adding the solution B into the solution A, reacting for 1-60min, and stopping stirring to obtain a mixed solution;

3) centrifuging the solution obtained in the step 2), washing for 3-5 times by deionized water, centrifuging to obtain the zinc-based flaky metal organic framework particle material, and placing the flaky metal organic framework particle material in a vacuum drying oven for 8-12 hours.

Further, the imidazole ligand is benzimidazole, 2-methylimidazole or aldehyde imidazole.

In the step 2), the molar ratio of zinc ions to imidazole in the two solutions is 1:5, and the reaction temperature is 20-60 ℃.

The zinc-based flaky metal organic framework particle material prepared by the method is in a flat cake shape, and the thickness of the particle is between 10nm and 100 nm; the shape of the periphery is oval or hexagonal, and the width and the length are between 200nm and 10 mu m.

The technical advantages of the invention are as follows:

1) the whole reaction does not involve organic solvents, and no pollution and interference of other organic solvents exist;

2) simple process, simple operation, easy synthesis method and preparation conditions.

Drawings

The following detailed description is made with reference to the accompanying drawings and embodiments of the present invention

Fig. 1 is a scanning electron microscope image of the flaky zinc nanoparticles prepared in examples 2 and 16;

(a) example 2, (b) example 16;

FIG. 2 is an X-ray diffraction pattern of the flaky zinc nanoparticles prepared in example 15;

FIG. 3 is an infrared spectrum of the flaky zinc nanoparticles prepared in example 15.

Detailed Description

The invention will be further described with reference to specific examples, but the scope of the invention is not limited thereto.

Example 1:

the preparation method of the zinc-based flaky metal organic framework particle material comprises the following specific steps:

adding 1.97g of 2-methylimidazole into 75g of deionized water, and naming the solution as solution A; adding 1.425g of zinc nitrate hexahydrate into 75g of deionized water, and naming as a solution B; adding the solution B into a separating funnel, then dropwise adding the solution B into the solution A, and stirring the solution A by a magnetic stirrer for 5min at a reaction temperature of 20 ℃; washing with deionized water for multiple times, centrifuging, and placing the product in a vacuum drying oven for 12h to obtain the flaky nano-particle material.

Examples 2 to 7:

example 2 the same as example 1 method, the difference is the reaction temperature is 25 degrees, 30 degrees, 35 degrees, 40 degrees, 45 degrees, 50 degrees, the reaction temperature is regulated. It was found that the size of the flaky zinc nanoparticles gradually changed with the increase of the reaction temperature, and the shape of the flaky zinc nanoparticles was more and more regular from a round-like shape of 1-3 μm to a regular hexagonal shape of 3-5 μm at 20 ℃.

Examples 8 to 17:

examples 8 to 15 were the same as in example 2 except that the reaction time of the solutions A and B was 10min, 30min, 1h, 2h, 3h, 5h, 8h, 10h, 12h and 24h, respectively. It was found that the thickness of the flaky zinc nanoparticles gradually changed with the increase of the reaction time, from 80nm to 200nm at 5min to about 1 μm at 24 h.

Claims

1. A preparation method of a zinc-based flaky metal organic framework particle material is characterized by comprising the following steps: the method comprises the following steps:

2. The method of claim 1, wherein: the imidazole ligand is benzimidazole, 2-methylimidazole or aldehyde imidazole.

3. The method of claim 2, wherein: in the step 2), the molar ratio of zinc ions to imidazole in the two solutions is 1:5, and the reaction temperature is 20-60 ℃.

4. A zinc based platelet metal organic framework particulate material obtainable by the process of any one of claims 1 to 3.

5. The zinc-based platelet metal organic framework particulate material of claim 4, wherein: the shape of the particle is flat cake shape, and the thickness is between 10nm and 100 nm; the shape of the periphery is oval or hexagonal, and the width and the length are between 200nm and 10 mu m.