Ferrocene-regulated MOF photo-thermal material as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of novel materials, and particularly discloses a ferrocene-regulated MOF photo-thermal material and a preparation method and application thereof.The preparation method comprises the following steps that pure cotton cloth is taken, subjected to ultrasonic cleaning with deionized water and ethyl alcohol in sequence and subjected to vacuum drying for use; the preparation method comprises the following steps: dissolving Cu (NO3) 2.3 H3O in an N, N-dimethylformamide solvent, stirring and fully dissolving, and soaking pure cotton cloth in the solution; adding a ligand 1, 3, 5-benzene tricarboxylic acid and ferrocene-1, 1 '-dicarboxylic acid, and stirring; transferring into a hydrothermal reaction kettle; after the reaction is finished, taking out the cotton cloth, soaking, washing and drying in vacuum to obtain the MOF loaded pure cotton cloth material regulated and controlled by ferrocene. According to the ferrocene-regulated MOF material and the preparation method and application thereof, pure cotton cloth serves as a carrier of the material, the photo-thermal performance is precisely regulated and controlled by adjusting the proportion of ferrocene carboxylic acid, the solar water evaporation efficiency is improved, the preparation process is simple, the cost is low, and the stability is good.

Description

Technical Field

[0001] This invention relates to the field of novel materials technology, and in particular to a ferrocene-regulated MOF photothermal material, its preparation method, and its application. Background Technology

[0002] Driven by both global water scarcity and the development of clean energy, solar water evaporation technology, with its advantages of low cost and zero pollution, has become an important direction for solving emergency water supply and seawater desalination problems. The development of high-performance photothermal materials is the core key to breakthroughs in this technology. Among them, ferrocene and its derivatives, as a typical class of organometallic compounds, exhibit excellent electron delocalization and charge transport capabilities due to their unique sandwich molecular structure. Furthermore, their molecular structure can be flexibly controlled through substituent modification, possessing strong and broad light absorption characteristics in the near-infrared region (accounting for approximately 50% of the solar spectrum). Upon photoexcitation, they can rapidly achieve electronic energy level transitions and efficiently convert light energy into heat energy, making them ideal photothermal functional units.

[0003] Metal-organic frameworks (MOFs) have shown great potential in photocatalysis and adsorption separation due to their high specific surface area, tunable pore structure, and abundant active sites. However, their light absorption range is mostly limited to the visible light region, and the high recombination rate of photogenerated carriers leads to low photothermal conversion efficiency, making it difficult to directly meet the application requirements of solar water evaporation. Introducing ferrocene and its derivatives into the MOF system can achieve a performance breakthrough through the synergistic effect of the two materials: on the one hand, the introduction of ferrocene derivatives can regulate the energy level difference of the frontier molecular orbitals of MOFs, narrow the band gap, and extend their light absorption range from the visible light region to the near-infrared region, significantly improving the utilization rate of solar energy; on the other hand, the charge transport characteristics of ferrocene units can effectively suppress the recombination of photogenerated carriers in MOFs, promote the directional conversion of light energy into heat energy, and thus greatly improve the overall photothermal conversion efficiency, providing a new approach for constructing high-efficiency photothermal materials.

[0004] However, current research on ferrocene derivative-regulated MOFs mainly focuses on photocatalytic degradation and electrochemical energy storage. Furthermore, the prepared composite materials are often loaded onto rigid supports (such as glass substrates and metal sheets) or exist in powder form, resulting in poor processability, high cost, and difficulty in large-scale application. In solar water evaporation scenarios, flexible, low-cost supports, due to their excellent hydrophilicity, air permeability, and water transport capabilities, enable efficient contact between photothermal materials and water bodies. They also possess portability and foldability, making them suitable for complex application environments such as field emergencies and mobile water purification, thus representing an ideal support choice. Therefore, there is an urgent need to develop a ferrocene-regulated MOF-based photothermal material with a simple preparation process and excellent performance, providing a material solution that combines performance and economy for the practical promotion of solar water evaporation technology. Summary of the Invention

[0005] The purpose of this invention is to provide a ferrocene-regulated MOF photothermal material, its preparation method, and its application. Using cotton cloth as a carrier, the photothermal performance is precisely controlled by adjusting the proportion of ferrocene carboxylic acid, thereby improving the solar water evaporation efficiency. Furthermore, the preparation process is simple, low-cost, and exhibits good stability. This invention solves the problems of low photothermal efficiency and poor carrier compatibility in existing MOF photothermal materials.

[0006] To achieve the above objectives, the present invention provides a method for preparing a ferrocene-regulated MOF photothermal material, comprising the following steps: Step 1, carrier pretreatment: Take pure cotton cloth, ultrasonically clean it with deionized water and ethanol for 10-20 minutes in sequence, and vacuum dry it at 60-80℃ for 2-4 hours for later use; Step 2, metal source adsorption: Dissolve Cu(NO3)2·3H3O in N,N-dimethylformamide solvent and stir at 25~35℃ for 2-4h until fully dissolved. Then soak the pretreated pure cotton cloth in Cu(NO3)2·3H3O / N,N-dimethylformamide solution for 2-4h to allow Cu(NO3)2 to be fully adsorbed on the surface of the cotton cloth and inside the fibers. Step 3, MOF in situ growth and control: Add ligands 1,3,5-benzenetricarboxylic acid and ferrocene-1,1'-dicarboxylic acid to the mixed solution in Step 2, and stir for 10~30 min; transfer the mixed system to a hydrothermal reactor and react at 120℃ for 12 h. Step 4, Post-processing: After the reaction is complete, take out the cotton cloth and soak and wash it with methanol and ethanol 3 to 5 times in sequence, soaking for 1 to 2 hours each time to remove unreacted raw materials and impurities. Then, vacuum dry it at 60 to 80°C for 4 to 6 hours to obtain ferrocene-regulated MOF-supported pure cotton cloth material.

[0007] Preferably, in step 2, the ratio of Cu(NO3)2·3H3O to N,N-dimethylformamide is 0.1~0.5mmol:10~30mL.

[0008] Preferably, in step 3, the molar ratio of 1,3,5-benzenetricarboxylic acid to Cu(NO3)2·3H2O is 1:1 to 1.5:1.

[0009] Preferably, in step 3, the molar ratio of ferrocene-1,1'-dicarboxylic acid to 1,3,5-benzenetricarboxylic acid is 0.1:1 to 0.5:1.

[0010] The present invention also provides a ferrocene-regulated MOF photothermal material, which is prepared by the above-described preparation method.

[0011] This invention also provides an application of ferrocene-regulated MOF photothermal material for solar-driven water evaporation.

[0012] The advantages and beneficial effects of the above-mentioned ferrocene-regulated MOF photothermal material, its preparation method, and its application are as follows: 1. This invention uses cotton fabric as a natural polymer carrier. Compared with traditional graphene, metal mesh, and sponges, it combines low cost, high flexibility, excellent water absorption and breathability, and potential biodegradability, making it more suitable for the large-scale and lightweight requirements of actual water evaporation scenarios. By combining the flexible cotton fabric carrier with ferrocene-functionalized MOFs, it utilizes the capillary action of cotton fabric to achieve efficient water transport, and enhances photothermal conversion through the controlled structure of MOFs, forming a synergistic system of "water transport-light absorption-heat generation." This fills the application gap of low-cost flexible carriers and functionalized MOFs in the field of solar water evaporation.

[0013] 2. By adjusting the ratio of Fc-2COOH to H3BTC, this invention can control the electronic structure and light absorption range of MOF, thereby increasing the light absorption efficiency of the material to over 90% in the wavelength range of 200~2500nm, and the photothermal conversion efficiency to a maximum of 98%.

[0014] 3. The porous structure of the pure cotton fabric carrier and the high specific surface area of ​​MOF in this invention work synergistically to improve the water transport and evaporation rate, achieving a speed of 1kW / m³. 2 Under simulated sunlight, the solar water evaporation rate can reach 1.8~2.5 kg / (m²). 2 The light absorption efficiency (·h) is far higher than that of traditional MOF materials. After 100 cycles of use, the material's light absorption efficiency and water evaporation rate still remain above 92% of their initial values, and the MOF does not show significant shedding on the pure cotton fabric surface.

[0015] The technical solution of the present invention will be further described in detail below through embodiments. Detailed Implementation

[0016] The technical solution of the present invention will be further described below through embodiments.

[0017] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.

[0018] The following examples are not intended to limit the invention, but are only for illustration. Unless otherwise specified, the experimental methods used in the following examples are generally performed under conventional conditions. Unless otherwise specified, the materials and reagents used in the following examples are commercially available.

[0019] Example 1 A method for preparing a ferrocene-regulated MOF photothermal material includes the following steps: Step 1, carrier pretreatment: Take pure cotton cloth, ultrasonically clean it with deionized water and ethanol for 10-20 minutes in sequence, and vacuum dry it at 60-80℃ for 2-4 hours for later use.

[0020] Step 2, Metal Source Adsorption: Dissolve Cu(NO3)2·3H3O in N,N-dimethylformamide (DMF) solvent and stir at 25-35℃ for 2-4 hours until fully dissolved. Then, soak the pretreated pure cotton cloth in the Cu(NO3)2·3H3O / N,N-dimethylformamide solution for 2-4 hours to allow for full adsorption of Cu(NO3)2 on the surface and inside the fibers of the cotton cloth. The ratio of Cu(NO3)2·3H3O to N,N-dimethylformamide is 0.1-0.5 mmol: 10-30 mL.

[0021] Step 3, MOF in-situ growth and control: Add ligands 1,3,5-benzenetricarboxylic acid (H3BTC) and ferrocene-1,1'-dicarboxylic acid (Fc-2COOH) to the mixed solution from Step 2, and stir for 10-30 min. Transfer the mixture to a hydrothermal reactor and react at 120℃ for 12 h; the molar ratio of 1,3,5-benzenetricarboxylic acid to Cu(NO3)2·3H2O is 1:1 to 1.5:1. The molar ratio of ferrocene-1,1'-dicarboxylic acid to 1,3,5-benzenetricarboxylic acid is 0.1:1 to 0.5:1.

[0022] Step 4, Post-processing: After the reaction is complete, take out the cotton cloth and soak and wash it with methanol and ethanol 3 to 5 times in sequence, soaking for 1 to 2 hours each time to remove unreacted raw materials and impurities. Then, vacuum dry it at 60 to 80°C for 4 to 6 hours to obtain ferrocene-regulated MOF-supported pure cotton cloth material.

[0023] The main component of pure cotton fabric is cellulose, whose molecular chain is rich in hydroxyl groups (-OH) and a small amount of natural carboxyl groups (-COOH), which can anchor Cu through coordination and electrostatic interactions. 2+ , making Cu 2+ Uniformly loaded onto the surface of pure cotton fabric and within the pores of the fibers, Cu becomes a "fixed metal node" for subsequent MOF growth, preventing MOF aggregation during the reaction. 2+ Porous crystalline materials are formed through carboxyl coordination with a dual-ligand (H3BTC as the main ligand and Fc-2COOH as the regulating ligand): the three -COO groups of H3BTC - With Cu 2+ Coordination occurs, forming a classic Cu-BTC MOF, with the two -COO groups of Fc-2COOH. - With Cu 2+Competitive coordination partially replaces H3BTC in the MOF framework. The degree of substitution is controlled by the content of Fc-2COOH, thereby regulating the structure and properties of the MOF, including electronic structure regulation (broadening light absorption and improving photothermal conversion efficiency) and pore structure / hydrophobicity regulation (water evaporation performance). When Fc-2COOH replaces part of H3BTC into the MOF framework, the conjugated π electrons of Fc undergo "electron delocalization" with the Cu-O coordination bonds of the MOF framework, narrowing the band gap of the MOF and extending the light absorption range from "ultraviolet-visible light" to "near-infrared light" (200~2500nm, covering the main energy region of sunlight); simultaneously, the dd transitions of the Fc group and The transition can effectively absorb photon energy and rapidly convert it into heat energy (photothermal conversion), avoiding energy loss in the form of fluorescence, etc. After the Fc group replaces part of H3BTC, it will slightly "expand" the microporous structure of MOF, while retaining the fiber pores of pure cotton fabric (micron-level), forming a multi-level "micron-nano" channel, which can quickly transfer moisture through capillary action (solving the problem of easy clogging of pure MOF channels); the Fc group has weak hydrophobicity, while the -COO of the MOF framework - The uncoordinated portion and the -OH group of pure cotton fabric are hydrophilic. This "weakly hydrophobic-hydrophilic" balance can prevent the material from absorbing too much water (leading to a decrease in photothermal efficiency), while ensuring the continuous transport of water within the channels, ultimately increasing the water evaporation rate. In addition, the "steric hindrance effect" and "coordination competition" of Fc-2COOH can be used to regulate the crystal growth direction, crystal face development, and dispersion of MOF, thereby controlling the morphology of MOF.

[0024] Example 2 A method for preparing a ferrocene-regulated MOF photothermal material includes the following steps: Step 1: Take a 1cm×1cm pure cotton cloth (0.1mm thick), ultrasonically clean it with deionized water and ethanol for 10 minutes each, and vacuum dry it at 60℃ for 2 hours.

[0025] Step 2: Dissolve 0.1 mmol Cu(NO3)2·3H2O in 10 mL N,N-dimethylformamide (DMF) solvent and stir at 20°C for 2 h. Then immerse the pretreated pure cotton cloth in Cu(NO3)2·3H2O / DMF solution to allow the cotton cloth to fully adsorb Cu(NO3)2 for 2 h.

[0026] Step 3: Add 0.1 mmol H3BTC and 0.01 mmol Fc-2COOH to the mixed solution in Step 2, stir for 10 min, transfer to a 50 mL hydrothermal reactor, and react at 120 °C for 12 h. Step 4: After the reaction is complete, take out the cotton cloth and wash it three times each with methanol and ethanol, soaking it for 1 hour each time to remove unreacted raw materials and impurities. Dry it under vacuum at 60°C for 4 hours to obtain ferrocene-regulated MOF-supported pure cotton cloth material, which is recorded as sample 1.

[0027] Sample 1 performance test: light absorption efficiency 88%, photothermal conversion efficiency 90%, 1kW / m 2 Evaporation rate under light: 1.8 kg / (m²) 2 ·h).

[0028] Example 3 A method for preparing a ferrocene-regulated MOF photothermal material includes the following steps: Step 1: Take a 3cm×3cm pure cotton cloth (0.2mm thick), ultrasonically clean it with deionized water and ethanol for 15 minutes each, and vacuum dry it at 70℃ for 3 hours.

[0029] Step 2: Dissolve 0.3 mmol Cu(NO3)2·3H2O in 20 mL N,N-dimethylformamide (DMF) solvent and stir at 30°C for 3 h. Then immerse the pretreated pure cotton cloth in Cu(NO3)2·3H2O / DMF solution to allow the cotton cloth to fully adsorb Cu(NO3)2 for 2 h.

[0030] Step 3: Add 0.4 mmol H3BTC and 0.1 mmol Fc-2COOH to the mixed solution from Step 2, stir for 20 min, then transfer to an 80 mL hydrothermal reactor and react at 120 °C for 12 h.

[0031] Step 4: After the reaction is complete, take out the cotton cloth and wash it with methanol and ethanol 4 times each, soaking it for 1.5 hours each time to remove unreacted raw materials and impurities. Dry it under vacuum at 70°C for 5 hours to obtain ferrocene-regulated MOF-supported pure cotton cloth material, which is designated as sample 2.

[0032] Sample 2 performance test: light absorption efficiency 92%, photothermal conversion efficiency 98%, 1kW / m 2 Evaporation rate under light: 2.5 kg / (m²) 2 ·h).

[0033] Example 4 A method for preparing a ferrocene-regulated MOF photothermal material includes the following steps: Step 1: Take a 5cm×5cm pure cotton cloth (0.3mm thick), ultrasonically clean it with deionized water and ethanol for 20 minutes each, and vacuum dry it at 80℃ for 4 hours.

[0034] Step 2: Dissolve 0.5 mmol Cu(NO3)2·3H2O in 30 mL N,N-dimethylformamide (DMF) solvent and stir at 35 °C for 4 h. Then soak the pretreated pure cotton cloth in Cu(NO3)2·3H2O / DMF solution to allow the cotton cloth to fully adsorb Cu(NO3)2 for 4 h.

[0035] Step 3: Add 0.75 mmol H3BTC and 0.25 mmol Fc-2COOH to the mixed solution from Step 2, stir for 30 min, then transfer to a 100 mL hydrothermal reactor and react at 120 °C for 12 h.

[0036] Step 4: After the reaction is complete, take out the cotton cloth and wash it with methanol and ethanol 5 times each, soaking it for 2 hours each time to remove unreacted raw materials and impurities. Dry it under vacuum at 80°C for 6 hours to obtain ferrocene-regulated MOF-supported pure cotton cloth material, which is designated as sample 3.

[0037] Sample 3 performance test: light absorption efficiency 90%, photothermal conversion efficiency 94%, 1kW / m 2 Evaporation rate under light: 2.2 kg / (m²) 2 ·h).

[0038] Comparative Example 1 Unlike Example 3, only 0.3 mmol H3BTC was added in step 3, and Fc-2COOH was not added. The rest of the steps were the same as in Example 3, and a comparison sample was obtained.

[0039] Comparative sample performance test: light absorption efficiency 70%, photothermal conversion efficiency 65%, 1kW / m 2 Evaporation rate under light: 1.2 kg / (m²) 2 ·h).

[0040] Therefore, this invention employs the aforementioned ferrocene-regulated MOF material, its preparation method, and its application. This material uses pure cotton cloth as a carrier, and its photothermal performance is precisely controlled by adjusting the proportion of ferrocene carboxylic acid. The photothermal conversion efficiency can reach up to 98%, 1kW / m². 2 The evaporation rate under light can reach 2.5 kg / (m²). 2 •h) Improves the efficiency of solar water evaporation, and the preparation process is simple, low-cost, and has good stability.

[0041] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for preparing ferrocene-regulated MOF photothermal material, characterized in that, Comprising the following steps: Step 1, carrier pretreatment: take pure cotton cloth, sequentially ultrasonic cleaning with deionized water, ethanol for 10-20 min, vacuum drying at 60-80℃ for 2-4h, ready for use; Step 2, metal source adsorption: dissolve Cu(NO3)2·3H3O in N,N-dimethylformamide solvent, stir at 25-35℃ for 2-4h, then fully dissolve, then immerse the pretreated pure cotton cloth in the Cu(NO3)2·3H3O / N,N-dimethylformamide solution for 2-4h, so that the surface and internal fibers of the cotton cloth fully adsorb Cu(NO3)2; Step 3, in-situ growth and regulation of MOF: add ligand 1,3,5-benzenetricarboxylic acid and ferrocene-1,1'-dicarboxylic acid to the mixed solution of step 2, stir for 10-30min; transfer the mixed system to a hydrothermal reactor, and react at 120℃ for 12h; Step 4, post-treatment: after the reaction is completed, take out the cotton cloth, sequentially immerse and wash with methanol and ethanol for 3-5 times, each time for 1-2h, remove unreacted raw materials and impurities, then vacuum dry at 60-80℃ for 4-6h, obtain the ferrocene-regulated MOF-loaded pure cotton cloth material.

2. The preparation method of the ferrocene-regulated MOF photothermal material according to claim 1, characterized in that: In step 2, the amount ratio of Cu(NO3)2·3H3O to N,N-dimethylformamide is 0.1-0.5mmol:10-30mL.

3. The preparation method of the ferrocene-regulated MOF photothermal material according to claim 1, characterized in that: In step 3, the molar ratio of 1,3,5-benzenetricarboxylic acid to Cu(NO3)2·3H2O is 1:1-1.5:

1.

4. The preparation method of the ferrocene-regulated MOF photothermal material according to claim 1, characterized in that: In step 3, the molar ratio of ferrocene-1,1'-dicarboxylic acid to 1,3,5-benzenetricarboxylic acid is 0.1:1-0.5:

1.

5. A ferrocene-regulated MOF photothermal material, characterized in that: It is prepared by the preparation method of any one of claims 1-4.

6. The use of a ferrocene-regulated MOF photothermal material according to claim 5, characterized in that: Applied to solar-driven water evaporation.