An MCu X Method for preparing / hcp-UiO composite material and application thereof

Abstract

The application belongs to the technical field of photocatalytic material preparation, and provides a novel PtCu 20 / hcp-UiO composite material and a preparation method and application thereof. The PtCu CuPSs / hcp-UiO composite material is synthesized by a solvothermal method, contains a Cu photosensitizer ligand L x , and is synthesized by solvothermal synthesis of hcp-UiO with different photosensitizer contents. The reaction temperature is 120-150 DEG C, heating is completed in a high-temperature and high-pressure reaction kettle for 24 hours, and a Cu x / hcp-UiO photocatalyst is obtained. Pt monatomic atoms are anchored on Cu x / hcp-UiO by an impregnation method by using N on a pyridine ring on the ligand, a series of catalysts are obtained, and Cu x / hcp-UiO, CoCu x / hcp-UiO, NiCu x / hcp-UiO, FeCu x / hcp-UiO) are anchored on Cu, Co, Ni and Fe monatomic atom catalysts by the same method. The PtCu 20 / hcp-UiO composite material synthesized by a two-step solvothermal one-step impregnation method has excellent photocatalytic activity and stability, can realize efficient photocatalytic hydrogen production, the preparation method is simple in operation, low in cost, friendly to the environment, has no harsh operation environment requirements, and is conducive to large-scale promotion.

Description

Technical Field

[0001] This invention belongs to the field of photocatalytic material preparation technology, specifically an MCu... X Preparation method and application of / hcp-UiO composite material. Background Technology

[0002] Energy and environmental issues are major global concerns, making it imperative to replace fossil fuels with clean, renewable energy sources to reduce dependence on them. A significant amount of energy reaches our planet as electromagnetic energy from the sun, and the rational utilization of clean, renewable solar energy is a viable path to solving current energy and environmental problems. Hydrogen, as one of the cleanest energy sources, has attracted widespread attention since the discovery of the Fujishima-Honda phenomenon in 1972; however, the precise design of catalysts remains a significant challenge.

[0003] Metal-organic frameworks (MOFs) possess customizable structures and variable pore environments, making them ideal materials for the precise design of photocatalysts. Furthermore, MOFs, composed of organic ligands and metal nodes, are naturally well-suited for constructing molecular heterostructures. In nature, photosynthesis is characterized by its green and efficient nature, and the light-reaction process in photosynthesis proceeds via a Z-scheme from the photosystem PSII to PSI via PET. Therefore, we simulated photosynthesis by integrating the photosystem LCuPS and the catalytically active site system LPt based on MOFs to construct a molecular S-type heterostructure.

[0004] Therefore, those skilled in the art have proposed an MCu X The preparation method and application of / hcp-UiO composite material for water decomposition and hydrogen production reaction are presented to address the problems raised in the background art. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide an MCu X The preparation method and application of / hcp-UiO composite materials are described. This preparation method is simple, cost-effective, environmentally friendly, and easy to scale up. The resulting MCu... X The / hcp-UiO composite material has the advantages of high photocatalytic activity and good stability, and can be applied to visible light photocatalytic hydrogen production.

[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0007] A type of MCu X The preparation method of / hcp-UiO composite material includes the following steps:

[0008] Step one, synthesizing ligand L with Cu photosensitizer by solvothermal method CuPSs Wherein, before adding (2,2'-dipyridyl)-5,5'-dicarboxylic acid, stirring at 10-50℃ for 0.5-5 hours, after adding (2,2'-dipyridyl)-5,5'-dicarboxylic acid, reacting at 10-50℃ for 5-15 hours;

[0009] Step two, synthesizing Cu photosensitizer-containing hcp-UiO by solvothermal method, which is completed by solvothermal method in an oven at 10-150℃ for 10-40 hours to obtain Cu x / hcp-UiO;

[0010] Step three, anchoring metal monatomic on the surface of Cu x / hcp-UiO by impregnation method, wherein stirring at 10-50℃ for 2-20 hours.

[0011] The MCu X / hcp-UiO composite material prepared by the above method can be used in photocatalytic water decomposition reaction.

[0012] Preferably, the volume ratio of CH2Cl2 / DMF is 10:1.

[0013] Preferably, the volume ratio of DMF / H2O / FA is 20:1:5.

[0014] Compared with the prior art, the present application has the following beneficial effects:

[0015] 1. The MCu X / hcp-UiO composite material synthesized by solvothermal method and one-step impregnation method has excellent photocatalytic activity and stability, and can efficiently realize water decomposition to produce hydrogen under visible light irradiation.

[0016] 2. The preparation method is simple in operation, low in cost, friendly to the environment, and has no harsh operation environment requirements, which is conducive to large-scale promotion. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 X-ray powder diffraction patterns of hcp-UiO, Pt / hcp-UiO, Cu 20 / hcp-UiO and PtCu 20 / hcp-UiO prepared in Example 1;

[0018] Figure 2 X-ray powder diffraction patterns of hcp-UiO, Pt / hcp-UiO, Cu 20 / hcp-UiO and PtCu 20UV-Vis absorption spectra of hcp-UiO;

[0019] Figure 3 hcp-UiO, Pt / hcp-UiO, Cu 20 / hcp-UiO and PtCu 20 Activity comparison plots of photocatalytic hydrogen evolution of hcp-UiO;

[0020] Figure 4 Cu 20 / hcp-UiO, PtCu 20 / hcp-UiO, CuCu 20 / hcp-UiO, CoCu 20 / hcp-UiO, NiCu 20 / hcp-UiO and FeCu 20 Activity comparison plots of photocatalytic hydrogen evolution of hcp-UiO. DETAILED DESCRIPTION

[0021] The embodiments of the present application will be further described in conjunction with the drawings and examples. The following examples are intended to illustrate the present application and should not be used to limit the scope of the present application.

[0022] As Figures 1 to 3 shown:

[0023] Example 1: MCu X Preparation of hcp-UiO catalyst:

[0024] (1) In a pre-dried three-necked round-bottom flask, tetraethylammonium copper hexafluorophosphate [Cu(CH3CN)4]PF6(93 mg, 0.25 mmol) and dimethyl-4,5-bis(diphenylphosphino)xanthine (XantP, 145 mg, 0.25 mol) were added in 10 mL of dichloromethane (CH2Cl2) and stirred under nitrogen atmosphere for 1 h; (2,2'-bipyridine)-5,5'-dicarboxylic acid (bpydc, 61 mg, 0.25 mmol) was added dropwise in a suspension in 20 mL of CH2Cl2 / DMF (10 / 1, v / v) and stirred under nitrogen atmosphere for another 6 h. The resulting liquid was collected and distilled under reduced pressure, and the resulting solid was collected;

[0025] (2) Synthesis of hcp-UiO with different contents of photosensitizer by solvothermal method (denoted as Cux / hcp-UiO, X is the percentage of photosensitizer contained in the ligand); add the total content of ligand of 0.3 mmol and ZrCl4 (0.3 mmol) in the reaction kettle, then gradually add 4 mL of DMF, 0.2 mL of deionized water, 1 mL of formic acid (FA), ultrasonic for 10 min, and finally put into the oven to heat at 150°C for 24 h; after cooling to room temperature, separate the solid by centrifugation (at a speed of 8000 r / min for 10 min), and then wash with N, N-dimethylformamide (DMF) and ethanol; finally, the solid powder collected by centrifugation is dried at 60°C under vacuum for 10 h;

[0026] (3) Anchoring Pt single atom on Cux / hcp-UiO by impregnation method (denoted as PtCux / hcp-UiO); add 40 mg of Cux / hcp-UiO, 20 mg of PtCl4, and 10 mL of DMF in a glass bottle, ultrasonic for 10 min; then stir for 10 h; finally separate the solid by centrifugation, and then wash with N, N-dimethylformamide (DMF) and ethanol for 3 times each; finally, the collected solid is dried at 60°C under vacuum for 10 h; in the same way, Cu, Co, Ni, and Fe units are anchored on Cux / hcp-UiO (denoted as CuCux / hcp-UiO, CoCux / hcp-UiO, NiCux / hcp-UiO, and FeCux / hcp-UiO, respectively).

[0027] Example 2

[0028] 1% Pt Cu 20 Preparation of / hcp-UiO catalyst:

[0029] 1.0wt% Pt supported Cu20 / hcp-UiO (denoted as 1% Pt Cu20 / hcp-UiO) was prepared by photodeposition; 0.0300 g of Cu20 / hcp-UiO was dispersed in 50 mL of solution (50 ml of deionized water and 198 μL of H2PtCl6 solution (0.08 M)), continuously stirred under the irradiation of a 300 W xenon lamp for 3 h; the product was collected by centrifugation, washed with deionized water for 3 times, and finally dried at 60°C for 10 h to obtain 1% Pt Cu20 / hcp-UiO. 20 / hcp-UiO.

[0030] Application Example 1

[0031] Photocatalytic hydrogen production performance test:

[0032] hcp-UiO, Cu 20 / hcp-UiO, PtCu20 Pt / hcp-UiO, 1%Pt / Cu 20 / hcp-UiO, CuCu x / hcp-UiO, CoCu x / hcp-UiO, NiCu x / hcp-UiO, FeCu x / hcp-UiO for photocatalytic hydrogen production reaction; the reaction was carried out in a closed system, the reactor volume was 100 mL, and a 300 W xenon lamp was used as the light source; 10 mg of sample was weighed and placed in the reactor, 39 mL of acetonitrile, 10 mL of triethanolamine and 1 mL of deionized water were added, and ultrasonic treatment was carried out for 10 minutes; high-purity nitrogen was continuously introduced for 10 minutes to expel air, and then the air valve was closed; after 4 h of illumination, the sample was quantitatively taken, and gas chromatography was used, and the results are as follows Figure 3 , 4 ;

[0033] As shown in Figure 3 , the photocatalytic hydrogen production rate of PtCu 20 / hcp-UiO composite material is 1.668 mmol·g -1 ·h -1 The photocatalytic hydrogen production rates of catalysts hcp-UiO, Cu 20 / hcp-UiO, PtCu 20 / hcp-UiO, Pt / hcp-UiO and 1%Pt / Cu 20 / hcp-UiO under the same conditions are respectively: 0.0018 mmol·g -1 ·h -1 , 0.385 mmol·g -1 ·h -1 , 0.116 mmol·g -1 ·h -1 and 0.778 mmol·g -1 ·h -1 .

[0034] As can be seen from the above, using light to decompose water to produce hydrogen not only saves energy and protects the environment, but also meets the concept of sustainable development; at the same time, the hydrogen generated in the catalytic process of the composite material is a valuable chemical product, which can be further used in industrial production or other fields. In addition, through performance comparison, it is found that the photocatalytic hydrogen production performance of sample PtCu 20 / hcp-UiO is much better than that of Cu 20 / hcp-UiO and Pt / hcp-UiO. It is shown that the ligands L Cu-PSs and L Pt in PtCu 20 / hcp-UiO form a molecular heterojunction, and the excellent performance comes from LCu-PSs and L Pt synergistic effect

[0035] As Figure 4 shown, the photocatalyst NiCu 20 / hcp-UiO, CoCu 20 / hcp-UiO, NiCu 20 / hcp-UiO CuCu 20 / hcp-UiO and FeCu 20 / hcp-UiO, the photocatalytic hydrogen production rates are: 1.053 mmol·g -1 ·h -1 , 0.778 mmol·g -1 ·h -1 , 0.389 mmol·g -1 ·h -1 , 0.271 mmol·g -1 ·h -1 .

[0036] From the above, Pt monatomic has more excellent photocatalytic activity than other metal monatomic.

[0037] In summary, PtCu 20 / hcp-UiO composite material is synthesized by a specific preparation process, which shows high catalytic activity in photocatalytic hydrogen production reaction; the experimental results show that the hydrogen production performance of the composite material is significantly higher than that of other control group materials. Therefore, it has potential industrial application value; it can be used for large-scale production of hydrogen and chemicals such as benzaldehyde, and provides a new efficient and environmentally friendly solution for industrial production.

[0038] The embodiments of the present application are given for example and description, although the embodiments of the present application have been shown and described above, it can be understood that the above-mentioned embodiments are exemplary and cannot be understood as limiting the present application, and those skilled in the art can make changes, modifications, replacements and variations to the above-mentioned embodiments within the scope of the present application.

Claims

1. A PtCu 20 The preparation method of / hcp-UiO composite material is characterized by: Includes the following steps: PtCu composite material synthesized using a two-step solvothermal, one-step impregnation method 20 / hcp-UiO, where 20 is the percentage of photosensitizer in the ligand; Step 1: Preparation of Cu photosensitizer ligands by solvothermal method: Copper hexafluorophosphate tetraacetonitrile, dimethyl-4,5-bis(diphenylphosphino)xanthine and the first solvent are mixed and stirred at a constant temperature of 10-50℃ for 0.5-5 hours; then (2,2'-bipyridine)-5,5'-dicarboxylic acid ligand is added, and the mixture is reacted at a constant temperature of 10-50℃ for 5-15 hours to obtain a mixture of Cu photosensitizer ligands; Step 2: Solvent-thermal synthesis of hcp-UiO containing Cu photosensitizer: ZrCl4 and a second solvent were added to the mixture obtained in Step 1. After thorough mixing, the mixture was transferred to a reaction vessel and subjected to a solvothermal reaction at 150°C for 10-40 hours. After the reaction was completed, the mixture was centrifuged, washed, and dried to obtain Cu. 20 / hcp-UiO material; Step 3: Impregnation method for loading platinum single atoms: The Cu prepared in step 2 is loaded with platinum single atoms... 20 The / hcp-UiO material was dispersed in a third solvent, PtCl4 was added, and the mixture was stirred at a constant temperature of 10~50℃ for 2~20 hours. After centrifugation, washing, and drying, the final PtCu was obtained. 20 / hcp-UiO composite material.

2. The PtCu as described in claim 1 20 The preparation method of / hcp-UiO composite material is characterized by: In step one, the first solvent is CH2Cl2 / DMF with a volume ratio of 10:

1.

3. A PtCu as described in claim 1 20 The preparation method of / hcp-UiO composite material is characterized by: In step two, the second solvent is DMF / H2O / FA ​​in a volume ratio of 20:1:5, where FA is formic acid.

4. A PtCu prepared by the method according to any one of claims 1-3 20 Application of / hcp-UiO composite material in photocatalytic hydrogen production.

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