阅读说明：本技术 一种苯并三噻吩类共价有机框架材料及其制备方法与应用 (Benzotriazole covalent organic framework material and preparation method and application thereof ) 是由 李留义 赵雲 于岩 于 2020-12-01 设计创作，主要内容包括：本发明公开了一种苯并三噻吩类共价有机框架材料及其制备方法与应用,其是以苯并三噻吩和2,5-二乙氧基对苯二甲酰肼为反应单体,二甲基亚砜为溶剂,醋酸为催化剂,经冷冻、解冻、抽真空、保温反应,制得所述共价有机框架材料。本发明制备条件温和,操作方便,成本低廉,所得苯并三噻吩类共价有机框架材料具有明确的孔隙、有序的孔道结构、大的表面积及低密度等多种结构特点,将其应用于光催化还原二氧化碳反应中,具有选择性强等优点,在光催化领域具有较大的应用潜力。(The invention discloses a benzotrithiophene covalent organic framework material and a preparation method and application thereof, wherein benzotrithiophene and 2, 5-diethoxy-p-phthalylhydrazide are used as reaction monomers, dimethyl sulfoxide is used as a solvent, acetic acid is used as a catalyst, and the covalent organic framework material is prepared by freezing, thawing, vacuumizing and heat-preserving reaction. The preparation method disclosed by the invention is mild in preparation conditions, convenient to operate and low in cost, and the obtained benzotrithiophene covalent organic framework material has multiple structural characteristics of definite pores, ordered pore channel structures, large surface area, low density and the like, is applied to a photocatalytic reduction carbon dioxide reaction, has the advantages of strong selectivity and the like, and has great application potential in the field of photocatalysis.)

1. A benzotrithiophene covalent organic framework material is characterized in that: the covalent organic framework material is formed by repeatedly connecting benzotrithiophene and 2, 5-diethoxy terephthaloyl hydrazine groups; the specific unit structural formula is as follows:

。

2. a method for preparing the benzotrithiophene covalent organic framework material of claim 1, comprising: the preparation method comprises the steps of taking benzotrithiophene and 2, 5-diethoxy-terephthaloyl hydrazine as reaction monomers, dimethyl sulfoxide as a solvent and acetic acid as a catalyst, putting the reaction monomers and the dimethyl sulfoxide in a glass test tube together, quickly freezing the reaction mixture in a liquid nitrogen bath, then unfreezing the reaction mixture, vacuumizing the reaction mixture to remove oxygen, sealing the glass test tube by flame, then heating the glass test tube to 80-120 ℃, and carrying out heat preservation reaction for 3-5 days to obtain the covalent organic framework material.

3. The method of preparing a benzotrithiophene-based covalent organic framework material of claim 2, wherein: the molar ratio of the benzotrithiophene to the 2, 5-diethoxyphthalhydrazide used was 3: 2.

4. The method of preparing a benzotrithiophene-based covalent organic framework material of claim 2, wherein: the concentration of the acetic acid is 3-6 mol/L.

5. Use of the benzotrithiophene covalent organic framework material of claim 1 in photocatalytic reduction of carbon dioxide.

Technical Field

The invention belongs to the field of preparation of photocatalytic materials, and particularly relates to a novel benzotrithiophene-linked covalent organic framework material, a synthesis method thereof and application thereof in photocatalytic reduction of carbon dioxide into carbon monoxide.

Background

With the development of science and technology and the improvement of the living standard of human beings, the content of carbon dioxide in the air is continuously increased, the greenhouse effect phenomenon caused by the carbon dioxide is intensified to cause a series of climatic abnormal phenomena such as glacier melting, typhoon and tornado lasting power time lengthening, and the like, and the improvement of the environmental protection consciousness of people is caused. Solar energy is used as inexhaustible energy, carbon dioxide is selectively converted into clean energy such as carbon monoxide and methane under illumination, consumption of non-renewable energy such as fossil energy can be reduced, pollution-free clean energy can be generated, and the solar energy is significant to environment and energy development.

Disclosure of Invention

Aiming at the limitation of the existing inorganic semiconductor material in the field of photocatalysis, the invention provides a novel benzotrithiophene covalent organic framework which is simple and convenient to prepare, low in cost and good in economic benefit and environmental benefit and a preparation method thereof.

In order to achieve the purpose, the invention adopts the following technical scheme:

a benzotrithiophene covalent organic framework material (BTT-COF), which is formed by repeatedly connecting benzotrithiophene and 2, 5-diethoxy terephthaloyl hydrazine groups; the specific unit structural formula is as follows:

。

the preparation method of the benzotrithiophene covalent organic framework material comprises the steps of taking benzotrithiophene and 2, 5-diethoxy terephthaloyl hydrazine as reaction monomers, taking dimethyl sulfoxide as a solvent and acetic acid as a catalyst, putting the benzotrithiophene and the 2, 5-diethoxy terephthaloyl hydrazine together into a glass test tube, quickly freezing the benzotrithiophene and the acetic acid in a liquid nitrogen bath, then unfreezing the benzotrithiophene and the acetic acid, vacuumizing the glass test tube to remove oxygen in the glass test tube, sealing the glass test tube by flame to avoid the oxidation side reaction of the oxygen on an amine-based raw material in the reaction process, then heating the glass test tube to 80-120 ℃, and carrying out heat preservation reaction for 3-.

Wherein the mol ratio of the benzotrithiophene to the 2, 5-diethoxyphthalhydrazide is 3: 2.

The concentration of the acetic acid is 3-6 mol/L.

Stirring and ultrasonically treating the obtained benzotrithiophene covalent organic framework material and a metal complex with the dosage of 10-20wt% in an organic solvent for 2-5 minutes under the condition of illumination and in a carbon dioxide atmosphere to combine an active site with metal ions, so that the carbon dioxide can be photo-catalytically reduced into carbon monoxide with high selectivity. Suitable metal complexes are, for example, Ni [ (ClO)₄]₂。

The invention has the beneficial effects that:

1) according to the invention, benzotriazole and 2, 5-diethoxy terephthaloyl hydrazine are used as reaction monomers, and a novel covalent organic framework material connected by imine is obtained through reaction in a dimethyl sulfoxide/acetic acid aqueous solution system, and the material has more micropore structures and heteroatoms, can be matched with metal ions, and realizes efficient photocatalytic reduction of carbon dioxide.

2) The equipment and chemical reagents used in the method are easy to obtain, the process operation is simple and convenient, the applicability is strong, the industrial application value is high, and the method is easy to popularize and utilize.

Drawings

FIG. 1 is a schematic diagram of the synthetic process for preparing BTT-COF according to the present invention;

FIG. 2 is an X-ray powder diffraction pattern of the benzotrithiophene used and the BTT-COF prepared in example 1;

FIG. 3 is a Fourier transform infrared spectrum of benzotrithiophene, 2, 5-diethoxyphthalhydrazide used in example 1 and BTT-COF prepared;

FIG. 4 is a nitrogen adsorption curve of BTT-COF prepared in example 1;

FIG. 5 shows the photocatalytic reduction of CO by BTT-COF prepared in example 1₂Is plotted against time.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more clearly understood and understandable, the present invention is further described in detail with reference to the following embodiments. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not to be construed as limiting the invention. In addition, the technical features mentioned in the embodiments of the present invention described below may be combined as long as they do not conflict with each other.

Example 1

Benzotriazole (13.22 mg, 0.02 mmol) and 2, 5-diethoxyphthalhydrazide (16.92 mg, 0.063 mmol) are placed in a Pyrex glass test tube (volume is about 5 mL, length is 20 cm, diameter is 1 cm), 0.8 mL of anhydrous dimethyl sulfoxide is added, ultrasonic treatment is carried out for 1 minute to ensure that the materials are uniformly dispersed, then 0.3 mL of 6M acetic acid is added, the Pyrex glass test tube is rapidly frozen and unfrozen in a liquid nitrogen bath, vacuum pumping is carried out for three times to remove oxygen and carry out flame sealing, then the Pyrex glass test tube is placed in an oven at 120 ℃ to react for 3 days after being heated to room temperature, after the reaction is finished, precipitates are collected by suction filtration and washed with DMF, methanol and dichloromethane for three times, and the obtained yellow powder is dried in vacuum at 60 ℃ overnight to obtain the covalent organic framework material BTT-COF.

FIG. 2 is an X-ray powder diffraction pattern of the benzotrithiophene used and the BTT-COF prepared. It can be observed from the figure that the characteristic diffraction peak of the monomer in the covalent organic framework material disappears, and the characteristic peak of the (100) crystal face appears at 2.7 degrees, which indicates the successful synthesis of the covalent organic framework material.

FIG. 3 is an infrared spectrum of the benzotrithiophene, 2, 5-diethoxyphthalhydrazide used and BTT-COF prepared. The results in the figure show that the length of the groove is 1600 cm^-1Characteristic peaks appearing there are assigned to the C = N group in the covalent organic framework, indicating successful synthesis of the covalent organic framework material.

FIG. 4 is a nitrogen adsorption curve of the BTT-COF prepared, and it can be seen that the BET specific surface area of the BTT-COF prepared reaches 426 m/g.

Example 2

10 mg of BTT-COF prepared in example 1 was weighed, and 2mg of Ni [ (ClO)₄]₂And 15 mg of 2,2' -bipyridine were put into a quartz glass reactor, and 5 mL of a mixed solution of acetonitrile/water/triethanolamine (3: 1:1 v/v/v) was added. After the reactor was evacuated, CO was introduced₂And the aeration was maintained for 15 minutes to fill the reactor with CO₂And sealing. Simulating visible light by using a 300W xenon lamp, irradiating the reactor for 4 hours at 303-323K, and collecting gas generated in the reactor by using an airtight injector (100 mu L) every 1 hour. Gas composition was measured by Shimadzu GC-2014 gas chromatography and was based on CO and H₂Content of (A) to plot the photocatalytic reduction of CO by BTT-COF₂Performance-time curve of (a).

The results show that the CO yield of 10 mg BTT-COF treated under the illumination condition for 4 hours can reach 880 micromoles, and the results show that the catalyst has good catalytic efficiency.

While the present invention has been described in detail with reference to the preferred embodiments, it should be understood that the above description should not be taken as limiting the invention. Various modifications and alterations to this invention will become apparent to those skilled in the art upon reading the foregoing description. Accordingly, the scope of the invention should be determined from the following claims.