Preparation of a UiO-66-NH2 / IISERP-COF12 composite material and photocatalytic carbon dioxide reduction

Abstract

The purpose of the present invention is to solve the problems of low efficiency of photocatalytic carbon dioxide reduction and easy recombination of photogenerated electrons and holes in existing materials, and to provide a UiO-66-NH2 / IISERP-COF12 composite material for preparation and photocatalytic carbon dioxide reduction. Method: 1. Prepare UiO-66-NH2MOFs material by solvothermal method; 2. Synthesize UiO-66-NH2 / IISERP-COF12 composite material by in situ addition of UiO-66-NH2. A UiO-66-NH2 / IISERP-COF12 composite carbon dioxide reduction photocatalyst material prepared by the present invention can produce carbon monoxide at a maximum rate of 109.21μmol·g- under visible light irradiation of a 300W xenon lamp. 1 ·h ‑1 , which is 22.66 times that of UiO-66-NH2 material and 3.5 times that of IISERP-COF12 material. The present invention can improve the problem of easy recombination of photogenerated electrons and holes and significantly improve the overall photocatalytic carbon dioxide reduction efficiency of the material.

Description

Technical Field

[0001] The present invention relates to the preparation of a UiO-66-NH2 / IISERP-COF12 composite material and photocatalytic carbon dioxide reduction. Background Art

[0002] Currently, with the rapid development of the global economy and the continuous growth of the global population, the global demand for energy is constantly increasing. The large-scale combustion of fossil fuels and the large-scale emission of automobile exhaust have a significant impact on global energy and environmental issues. Energy shortages and environmental pollution have become common problems faced by people all over the world. The main substance causing this situation is CO2. In this context, the search for clean and renewable energy to replace the increasingly depleted fossil energy has become more urgent. While there are many methods for converting CO2, in recent years, the conversion of CO2 through photocatalysis has undoubtedly become the cleanest and most effective method. However, existing photocatalysts have low light utilization efficiency and easy electron-hole recombination, which limits the use of solar energy. Therefore, the development of new and efficient photocatalysts that can maximize the utilization of visible light is urgent.

[0003] Metal-organic frameworks (MOFs) are a class of organic-inorganic hybrid porous crystalline materials with two- or three-dimensional structures that have emerged in recent years. They are coordination compounds formed by metal ions or metal clusters acting as connecting nodes, coordinated with organic ligands. Due to their unique electronic band structure, customizable light absorption, high CO₂ adsorption, and high specific surface area, MOFs are widely used as photocatalysts or supports for photocatalytic applications. Their unique electronic band structure also provides suitable conditions for the formation of heterogeneous structures.

[0004] Covalent organic frameworks (COFs) are porous crystalline polymers with modularity, porosity, crystallinity, structural tunability, and semiconductor properties. This makes COFs highly promising in a variety of fields, including gas adsorption and separation, catalysis, sensing, energy storage, and photoelectric conversion, and has led to their widespread development. However, COFs photocatalysts based on individual components have a low visible light utilization rate, which limits further improvement in the CO2 reduction activity of COFs photocatalysts. Therefore, developing a material with high photocatalytic CO2 reduction efficiency has become a research hotspot. Summary of the Invention

[0005] The purpose of the present invention is to solve the problems of low efficiency of photocatalytic carbon dioxide reduction and easy recombination of photogenerated electrons and holes in existing materials, and to provide a UiO-66-NH2 / IISERP-COF12 composite material for preparation and photocatalytic carbon dioxide reduction.

[0006] The preparation of a UiO-66-NH2 / IISERP-COF12 composite material and the photocatalytic carbon dioxide reduction of the present invention are completed according to the following steps:

[0007] Step 1, preparation of UiO-66-NH2 material: zirconium chloride (ZrCl4), 2-aminoterephthalic acid (ATA), a regulator (3,5-diaminoterephthalic acid (2ABA)), and 5ml of DMF were added to a beaker in sequence. The resulting solution was ultrasonically treated for 30 minutes to uniformly disperse it. The sample in the beaker was transferred to a polytetrafluoroethylene autoclave, 0.6mL of glacial acetic acid was added, and it was placed in an oven and heated. The resulting product was filtered and washed with DMF, EtOH, and deionized water, respectively, to obtain a light yellow solid powder, recorded as UiO-66-NH2.

[0008] Step 2, preparation of UiO-66-NH2 / IISERP-COF12 composite material: 5,5,5-(1,3,5-triazine-2,4,6-triyl)tris(pyridin-2-amine), 1,3,5-trialdehyde phloroglucinol and UiO-66-NH2 obtained in step 1 were placed in a heat-resistant glass tube, and dimethyl sulfoxide (DMSO) and ethanol solution were added in sequence. Ultrasonic treatment was performed at an ultrasonic frequency of 35 to 45 kHz for 30 to 35 min, and then 6 mol·L -1 The acetic acid solution was degassed by three freeze-thaw cycles in a liquid nitrogen bath, sealed, heated at 120 °C for 72 h, filtered, washed several times with DMSO and ethanol, and dried to obtain the UiO-66-NH2 / IISERP-COF12 composite material;

[0009] The molar ratio of zirconium chloride (ZrCl4) to 2-aminoterephthalic acid (ATA) in step 1 is 1:1;

[0010] After sealing as described in step 1, heat at 120°C for 24 hours;

[0011] The molar ratio of 5,5,5-(1,3,5-triazine-2,4,6-triyl)tris(pyridin-2-amine) and 1,3,5-trialdehyde phloroglucinol in step 2 is 1:1;

[0012] The volume ratio of DMSO, ethanol and acetic acid in step 2 is 1:1:0.3;

[0013] The concentration of the acetic acid solution used in step 2 is 6 mol·L -1 ;

[0014] After sealing as described in step 2, heat at 120°C for 72h;

[0015] Application of the above-mentioned UiO-66-NH2 / IISERP-COF12 composite material in photocatalytic carbon dioxide reduction.

[0016] Beneficial effects of the present invention:

[0017] The present invention adopts the solvent thermal method, uses zirconium chloride (ZrCl4) and 2-aminoterephthalic acid (ATA) as raw materials, and successfully synthesizes UiO-66-NH2. However, the carbon dioxide reduction efficiency of this material under visible light is low, only 4.82μmol·h -1 ·g -1 Therefore, the present invention combines UiO-66-NH2 with IISERP-COF12 to synthesize a new composite material, UiO-66-NH2 / IISERP-COF12, which effectively improves the photocatalytic carbon dioxide reduction performance. The photocatalytic carbon dioxide reduction efficiency of the UiO-66-NH2 / IISERP-COF12 composite material is 109.21 μmol·h -1 ·g -1 . BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 X-ray powder diffraction pattern of UiO-66-NH2 / IISERP-COF12 material;

[0019] Figure 2 This is the UV-visible absorption spectrum of UiO-66-NH2 / IISERP-COF12 material;

[0020] Figure 3 The energy band structure diagram of UiO-66-NH2 / IISERP-COF12 material;

[0021] Figure 4 Performance diagram of UiO-66-NH2 / IISERP-COF12 material DETAILED DESCRIPTION

[0022] The present invention is further described below with reference to examples. These examples are merely for illustrating the method of the present invention and have no limitation on the scope of application of the present invention.

[0023] Example 1: The preparation of a UiO-66-NH2 / IISERP-COF12 material of this embodiment is completed by the following steps:

[0024] Step 1, Preparation of UiO-66-NH2: First, 11.65 mg of zirconium chloride (ZrCl4) and 9.05 mg of 2-aminoterephthalic acid (ATA) were added to a beaker, and 5 mL of DMF solution was added. The resulting solution was ultrasonically treated for 30 minutes to make it uniformly dispersed. The mixed solution was then transferred to an autoclave, 0.6 mL of glacial acetic acid was added, and the autoclave was placed in an oven at 120°C for 24 hours. The resulting product was filtered and washed with DMF, EtOH, and deionized water, respectively, to obtain a light yellow solid powder, recorded as UiO-66-NH2;

[0025] Step 2, preparation of UiO-66-NH2 / IISERP-COF12 composite material: 5,5,5-(1,3,5-triazine-2,4,6-triyl)tris(pyridin-2-amine), 1,3,5-trialdehyde phloroglucinol and UiO-66-NH2 obtained in step 1 were placed in a heat-resistant glass tube, and dimethyl sulfoxide (DMSO) and ethanol solution were added in sequence. Ultrasonic treatment was carried out at an ultrasonic frequency of 35-45 kHz for 30-35 min, and then 6 mol·L -1 The acetic acid solution was degassed by three freeze-thaw cycles in a liquid nitrogen bath, sealed, heated at 120 °C for 72 h, filtered, washed with DMSO and ethanol several times, and dried to obtain the UiO-66-NH2 / IISERP-COF12 composite material.

[0026] Characterization of a UiO-66-NH2 / IISERP-COF12 composite material:

[0027] The obtained UiO-66-NH2 / IISERP-COF12 composite material was subjected to XRD test. Figure 1 It can be seen that the peak position of the diffraction peak of the composite material contains the characteristic peaks of two independent materials, and the peak height changes with the change of the ratio, which is consistent with the basic characteristics of the composite material and illustrates the successful synthesis of the composite material.

[0028] The obtained UiO-66-NH2 / IISERP-COF12 composite material was subjected to UV-visible absorption spectrum test. Figure 2 It can be seen that the band gap width of UiO-66-NH2 is 2.83eV, and the band gap width of IISERP-COF12 is 1.95eV. The band structure of the overall material is obtained by calculation as shown in Figure 3 shown.

[0029] The following tests were performed to verify the beneficial effects of the present invention:

[0030] In order to investigate the photocatalytic carbon dioxide reduction effect of the UiO-66-NH2 / IISERP-COF12 composite material, its photocatalytic carbon dioxide reduction performance was tested according to the following method. The test process is as follows: A gas-solid photocatalytic reaction device is used. Before the sample test, the sample needs to be pretreated. The operation is as follows: 10 mg of catalyst is ultrasonically dispersed in 1 mL of acetone, the dispersed liquid is dropped into a specific glass piece, and then the glass piece is placed in a gas-solid reactor, and 99.9% CO2 gas is introduced into the device. After 30 minutes, the reaction device is sealed. The reaction system is irradiated under a 300WXe lamp (filter λ>420nm), and the condensing device is turned on to ensure that the system is at room temperature. Since the light source is turned on, a gas sample in the system is collected once every 1 hour, and it is injected into the FID detection port of the GC7920 gas chromatograph to determine the CO gas content. The sample is tested five times, and the photocatalytic reaction takes a total of five hours. As Figure 4 The reduction rate of carbon dioxide to carbon monoxide can reach 109.21 μmol·g -1 ·h -1 , which is 22.66 times that of UiO-66-NH2 material and 3.5 times that of IISERP-COF12 material.

Claims

1. A method for preparing a UiO-66-NH2 / IISERP-COF12 composite material, characterized in that The method is carried out according to the following steps: Step 1, Preparation of UiO-66-NH2: First, 11.65 mg of zirconium chloride (ZrCl4) and 9.05 mg of 2-aminoterephthalic acid (ATA) were added to a beaker, and then 5 mL of DMF solution was added. The resulting solution was ultrasonically treated for 30 min to make it uniformly dispersed; then the mixed solution was transferred to an autoclave, 0.6 mL of glacial acetic acid was added, and the autoclave was placed in an oven at 120°C for 24 h. The resulting product was filtered and washed with DMF, EtOH, and deionized water respectively to obtain a light yellow solid powder, recorded as UiO-66-NH2; Step 2. Preparation of UiO-66-NH2 / IISERP-COF12 composite material: 5,5,5-(1,3,5-triazine-2,4,6-triyl)tris(pyridin-2-amine), 1,3,5-trialdehyde phloroglucinol and UiO-66-NH2 obtained in step 1 were placed in a heat-resistant glass tube, and dimethyl sulfoxide (DMSO) and ethanol solution were added in sequence. The mixture was ultrasonically treated at an ultrasonic frequency of 35-45 kHz for 30-35 min, and then 6 mol·L -1 The acetic acid solution was degassed by three freeze-thaw cycles in a liquid nitrogen bath, sealed, heated at 120 °C for 72 h, filtered, washed several times with DMSO and ethanol, and dried to obtain the UiO-66-NH2 / IISERP-COF12 composite material; UiO-66-NH2 was in situ added into the synthesis system of IISERP-COF12 material; In step 2, the volume ratio of dimethyl sulfoxide (DMSO) to ethanol solution is 1:1.

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