A metal-organic framework nanomaterial with adjustable photothermal performance and a preparation method thereof

Abstract

The application relates to the technical field of energy conversion materials, and discloses a metal organic framework nanomaterial with adjustable photothermal performance and a preparation method thereof. The method uses two ligands with different functional groups, 2-amino terephthalic acid and 2-fluoro terephthalic acid, to control the near-infrared light absorption capacity of the metal organic framework, so that the photothermal conversion temperature is accurately controlled by changing the ligand ratio. Compared with the traditional method of improving the photothermal performance by changing the light power density, the metal organic framework nanomaterial provided by the application has significant advantages in the preparation process, structure controllability and photothermal conversion performance regulation.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of energy conversion materials, and particularly relates to a metal-organic framework nanomaterial with adjustable photothermal performance and a preparation method thereof. BACKGROUND

[0002] As a renewable clean energy, efficient storage and utilization of light energy is of great significance to promote sustainable development strategy. Photothermal conversion materials are the key medium for converting light energy into heat energy. Such materials convert light energy into heat energy through various photothermal conversion mechanisms, and their light absorption capacity and photothermal conversion efficiency can be adjusted by optimizing the microstructure and macrostructure of the materials to achieve efficient utilization of light energy.

[0003] At present, photothermal materials are mainly divided into four categories: noble metal nanomaterials (gold nanorods and gold nanowires), transition metal materials (MoS2 and WS2), carbon-based nanomaterials (carbon nanotubes and graphene oxide), and organic conjugated materials (cyanine and porphyrin). Although these photothermal materials have made some progress in research, there are still many problems such as high cost, non-degradability, and biological toxicity. For example, noble metal nanomaterials are high in cost and non-degradable; transition metal materials may have poor light stability; carbon-based nanomaterials may have biological toxicity; organic conjugated materials usually involve the synthesis of toxic chemical reagents, and their structure is unstable and prone to photobleaching.

[0004] Therefore, it is an urgent need to develop an environmentally friendly, stable, and efficient photothermal conversion material to realize low-carbon economy and sustainable development. SUMMARY

[0005] The present application aims to solve the problem of uncontrollable structure of existing organic photothermal materials, and provides a metal-organic framework nanomaterial with adjustable photothermal performance and a preparation method thereof. The present application adjusts the absorption capacity of metal-organic framework to near-infrared light by using ligands 2-amino terephthalic acid and 2-fluoro terephthalic acid with different functional groups, thereby realizing the regulation of photothermal conversion temperature by precisely controlling the ratio of ligands.

[0006] The specific technical solutions of the present application include:

[0007] On the one hand, the present application provides a metal-organic framework nanomaterial with adjustable photothermal performance, which is formed by complexing zirconium ions with ligands, the ligands being 2-amino terephthalic acid or / and 2-fluoro terephthalic acid, and the material realizing the regulation of its photothermal performance by adjusting the ratio of amino and fluoro groups in the material.

[0008] The present application can precisely adjust the absorption of near-infrared light and the photo-thermal conversion efficiency of the material by introducing ligands 2-amino terephthalic acid and 2-fluoro terephthalic acid with different functional groups into the metal organic framework and adjusting the ratio of the two, so as to realize the adjustability of the photo-thermal conversion temperature.

[0009] In another aspect, the present application also provides a preparation method of the metal organic framework nanomaterial with adjustable photo-thermal performance, comprising the following steps:

[0010] The zirconium salt and the ligand are dissolved in a solvent, ultrasonic treatment is performed, and then the solid is separated to obtain a metal organic framework nanomaterial; wherein:

[0011] The ligand is obtained by mixing 2-amino terephthalic acid and 2-fluoro terephthalic acid at a molar ratio of 0-10:10-0.

[0012] In the above preparation method, preferably, the molar ratio of the zirconium salt to the ligand is 1: (1-1.2).

[0013] As a preferred embodiment of the above preparation method, the solvent is a mixed solvent of dimethylformamide, acetic acid and water.

[0014] As a preferred embodiment of the above preparation method, preferably, the volume ratio of dimethylformamide, acetic acid and water is 15:6:1.

[0015] Dimethylformamide can effectively dissolve the ligand, acetic acid can adjust the acidity and alkalinity of the solvent, and promote the growth of the metal organic framework nanomaterial. The addition of an appropriate amount of water is helpful for the crystallization of the crystal.

[0016] As a preferred embodiment of the above preparation method, the zirconium salt is zirconium chloride or / and zirconium nitrate.

[0017] As a preferred embodiment of the above preparation method, the ultrasonic treatment time is 4-10 minutes.

[0018] As a preferred embodiment of the above preparation method, the standing temperature is 120-160℃, and the standing time is 20-30 hours.

[0019] The standing step is crucial for the crystallization of the metal organic framework. Appropriate temperature and time can ensure the crystallinity and structural stability of the material. If the temperature is too high or too low, it will affect the nucleation efficiency of the metal organic framework, and further affect the performance of the material. Therefore, in the present application, the crystallization and precipitation of the metal organic framework nanomaterial requires standing at a temperature of 120-160℃ for 20-30 hours. If the temperature deviates from this range, it may lead to incomplete or uneven nucleation of the crystal, and further affect the quality and performance of the material.

[0020] As a preferred preparation method, the method of separating the solid is centrifugation, and ethanol is used for washing to remove impurities, so as to ensure that the metal organic framework nanomaterial with high purity is obtained.

[0021] Compared with the prior art, the present application has the following technical effects:

[0022] 1. By accurately controlling the ratio of two ligands, 2-amino terephthalic acid and 2-fluoro terephthalic acid, the absorption of metal organic framework to near-infrared light can be effectively regulated, and the photothermal conversion temperature can be accurately adjusted, realizing the controllability of photothermal performance.

[0023] 2. The preparation method is simple and low in cost, does not need complex chemical synthesis steps, conforms to the principle of environmental protection preparation, and provides an efficient and economical new way for regulating the photothermal conversion efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 The photothermal conversion test results of the metal organic framework materials prepared in examples 1 to 5 of the present application;

[0025] Figure 2 The cycle stability test results of the metal organic framework materials prepared in examples 1 to 5 of the present application;

[0026] Figure 3 The test results of temperature difference change with power density of the metal organic framework materials prepared in examples 1 to 5 of the present application. DETAILED DESCRIPTION

[0027] The present application will be further described below in combination with examples. For ordinary skilled persons in the art, the present application can be successfully implemented on the basis of fully understanding the following description. In addition, the following examples are only a part of the present application and do not cover all the embodiments. Therefore, any simple modification, change or equivalent replacement made on the basis of the technical solutions of the present application shall fall within the protection scope of the present application.

[0028] Example 1

[0029] The present embodiment provides a preparation method of a metal organic framework material. The specific preparation steps are as follows:

[0030] Firstly, ligands 2-amino terephthalic acid (NH2-BDC) and 2-fluoro terephthalic acid (F-BDC) are prepared in a molar ratio of 10:0. Specifically, 0.15 g of ZrCl4 and 0.176 g of NH2-BDC are weighed.

[0031] Then, the solid material was dissolved in a mixture solution composed of 15 mL dimethylformamide (DMF), 6 mL acetic acid and 1 mL deionized water. After the material was completely dissolved, the solution was placed in an ultrasonic bath for 5 minutes.

[0032] After the ultrasonication, the solution was left to stand at 150 °C for 24 hours. After the standing, the solid was separated by centrifugation at 8000 rpm for 3 minutes, the supernatant was removed and the precipitate was washed with 15 mL of ethanol. This step was repeated three times to ensure that the precipitate was well washed.

[0033] Finally, the obtained precipitate was vacuum dried at 60 °C for 12 hours to obtain metal organic framework nanoparticles with a ligand molar ratio NH2-BDC:F-BDC = 10:0.

[0034] Example 2

[0035] This example differs from example 1 only in that the ligands 2-aminoterephthalic acid (NH2-BDC) and 2-fluoroterephthalic acid (F-BDC) were prepared in a molar ratio of 7:3, specifically: 0.15 g of ZrCl4, 0.123 g of NH2-BDC and 0.0528 g of F-BDC were weighed. The other steps were the same as in example 1.

[0036] Example 3

[0037] This example differs from example 1 only in that the ligands 2-aminoterephthalic acid (NH2-BDC) and 2-fluoroterephthalic acid (F-BDC) were prepared in a molar ratio of 5:5, specifically: 0.15 g of ZrCl4, 0.088 g of NH2-BDC, 0.087 g of F-BDC were weighed. The other steps were the same as in example 1.

[0038] Example 4

[0039] This example differs from example 1 only in that the ligands 2-aminoterephthalic acid (NH2-BDC) and 2-fluoroterephthalic acid (F-BDC) were prepared in a molar ratio of 3:7, specifically: 0.15 g of ZrCl4, 0.0528 g of NH2-BDC, 0.123 g of F-BDC were weighed. The other steps were the same as in example 1.

[0040] Example 5

[0041] The embodiment is compared with example 1, the difference is only that ligand 2-amino terephthalic acid (NH2-BDC) and 2-fluoroterephthalic acid (F-BDC) are prepared in a molar ratio of 0:10, specifically: 0.15 g of ZrCl4 and 0.176 g of F-BDC are weighed. The other steps are the same as example 1.

[0042] Comparative example 1

[0043] The comparative example is compared with example 1, the difference is only that the weighed substances are dissolved together in 15 mL of DMF. The other steps are the same as example 1.

[0044] The comparative example finds that after standing at 150℃ for 24h and then centrifuging at a speed of 8000rpm for 3 minutes, no precipitate is obtained.

[0045] Comparative example 2

[0046] The comparative example is compared with example 1, the difference is only that the weighed substances are dissolved together in a mixed solution of 15 mL of DMF and 7 mL of acetic acid. The other steps are the same as example 1.

[0047] The comparative example finds that after standing at 150℃ for 24h and then centrifuging at a speed of 8000rpm for 3 minutes, less precipitate is obtained, and after three washes, there is little precipitate left.

[0048] Performance test

[0049] (1) The metal-organic framework materials prepared in examples 1-5 were tested for light-heat conversion, and the results are shown in Figure 1 wherein: example 1 represents example 1, example 2 represents example 2,..., and example 5 represents example 5. The test method and test conditions are as follows: 10 mg of metal-organic framework material is placed in a glass container, and the metal-organic framework is irradiated at a height of 20 cm with an 808 nm infrared exciter, and the surface temperature change of the metal-organic framework is recorded with an infrared thermal imager.

[0050] From Figure 1 It can be seen that the temperature of the metal-organic framework with only amino groups is the highest, and from the characterization results of examples 1-5, it can be seen that as the content of amino groups decreases and the content of fluorine groups increases, the temperature of the metal-organic framework decreases.

[0051] (2) The metal-organic framework materials prepared in examples 1-5 were tested for cyclic stability, and the results are shown in Figure 2Wherein: instance 1 represents example 1, instance 2 represents example 2,..., instance 5 represents example 5. The test method and test setting conditions are as follows: 10 mg of metal organic framework material is placed in a glassware, the metal organic framework is irradiated at a height of 20 cm with an infrared exciter of 808 nm, and the surface temperature change of the metal organic framework is recorded with an infrared thermal imager.

[0052] From Figure 2 It can be seen that the materials obtained in examples 1-5 have almost no difference in temperature after 3 cycles of photo-thermal conversion, and the cycle stability of the materials obtained in examples 1-5 is excellent.

[0053] (3) The temperature difference of the metal organic framework materials prepared in examples 1-5 with power density is tested, which refers to the difference between the highest temperature and the lowest temperature of the material after multiple tests of photo-thermal conversion of the material under the same power. The photo-thermal conversion test method and setting conditions are referred to step (1). The test results of the temperature difference with power density are shown in Figure 3 Wherein: instance 1 represents example 1, instance 2 represents example 2,..., instance 5 represents example 5.

[0054] From Figure 3 The characterization results of examples 1-5 in table 1 show that as the irradiation power density increases, the higher the amino content, the greater the temperature difference; the higher the fluorine content, the smaller the temperature difference.

[0055] The raw materials and equipment used in the present application are conventional raw materials and equipment in the art unless otherwise specified; the methods used in the present application are conventional methods in the art unless otherwise specified.

[0056] The above is only a preferred embodiment of the present application, and does not limit the present application in any way, and any simple modification, change and equivalent transformation of the above embodiment according to the technical essence of the present application still belongs to the protection scope of the technical solution of the present application.

Claims

1.A method for preparing a metal-organic framework nanomaterial with adjustable photothermal performance, comprising the following preparation steps: dissolving a zirconium salt and a ligand in a solvent, ultrasonicating, standing for reaction, separating a solid, and obtaining a metal-organic framework nanomaterial; the metal-organic framework nanomaterial is formed by complexing zirconium ions with the ligand; the ligand is 2-amino terephthalic acid and 2-fluoro terephthalic acid; the photothermal performance of the metal-organic framework nanomaterial is adjusted by adjusting the content ratio of amino groups and fluoro groups in the material; wherein: the ligand is obtained by mixing 2-amino terephthalic acid and 2-fluoro terephthalic acid at a molar ratio of 0-10:10-0, and the amount of 2-amino terephthalic acid and 2-fluoro terephthalic acid is not 0; the molar ratio of the zirconium salt to the ligand is 1:1-1.2; the solvent is a mixed solvent of dimethylformamide, acetic acid and water; the volume ratio of dimethylformamide, acetic acid and water is 15:6:1; the zirconium salt is zirconium chloride and / or zirconium nitrate; the ultrasonicating time is 4-10 minutes; the standing temperature is 120-160℃, and the standing time is 20-30 hours; and the method for separating the solid is centrifugation. ​ ​ ​ ​ ​ ​ ​ 2. The production method according to claim 1, characterized by: ​ 3. The production method according to claim 1, wherein: ​ 4. The production method according to claim 1, wherein: ​ 5. The production method according to claim 1, wherein: ​

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