Preparation method and application of MCuX / hcp-UiO composite material

Abstract

The invention belongs to the technical field of photocatalytic material preparation, and provides a novel PtCu20 / hcp-UiO composite material and a preparation method and application thereof.The novel PtCu20 / hcp-UiO composite material is characterized in that a Cu photosensitizer-containing ligand LCuPSs is synthesized through a solvothermal method, hcp-UiO with different photosensitizer contents is synthesized through solvothermal, the reaction temperature is 120-150 DEG C, heating is completed for 24 hours in a high-temperature and high-pressure reaction kettle, and a Cux / hcp-UiO photocatalyst is obtained; a series of catalysts are obtained by anchoring Pt monatomic on Cux / hcp-UiO by using N on a pyridine ring on a ligand through an impregnation method, and Cu, Co, Ni and Fe monatomic catalysts anchored on Cux / hcp-UiO are obtained by using the same method and are recorded as CuCux / hcp-UiO, CoCux / hcp-UiO, NiCux / hcp-UiO and FeCux / hcp-UiO; the PtCu20 / hcp-UiO composite material synthesized by utilizing a two-step solvothermal one-step impregnation method has excellent photocatalytic activity and stability and can realize efficient photocatalytic hydrogen production, and meanwhile, the preparation method is simple to operate, low in cost, environment-friendly, free of harsh operating environment requirements and beneficial to large-scale popularization.

Description

Technical Field

[0001] The present invention belongs to the technical field of photocatalytic material preparation, and is specifically a MCu X Preparation method and application of / hcp-UiO composite materials. Background Art

[0002] Energy and environmental issues are a hot topic in today's world. Therefore, there is an urgent need for clean renewable energy to replace fossil energy and reduce dependence on fossil energy. A large amount of energy reaches our planet in the form of electromagnetic energy from the sun. The rational use of clean and renewable solar energy is a feasible path to solve the current energy and environmental problems. Hydrogen is one of the cleanest energy sources. Since the Fujishima-Honda phenomenon was discovered in 1972, solar-driven hydrogen has attracted widespread attention, but the precise design of the catalyst is still a major problem.

[0003] Metal-organic frameworks (MOFs) have the characteristics of customizable structure and variable pore environment, making them ideal materials for the precise design of photocatalysts. In addition, MOFs are composed of organic ligands and metal nodes, which are naturally suitable for constructing molecular heterojunctions. In nature, photosynthesis is green and efficient, and the light reaction in photosynthesis is carried out through the Z scheme of PET from photosystem PSII to PS I. Therefore, we simulated photosynthesis based on MOFs to integrate the photosystem L Cu PS and the catalytic active site system L Pt to construct a molecular S-type heterojunction.

[0004] To this end, those skilled in the art have proposed a MCu X / hcp-UiO composite material preparation method and application to decompose water to produce hydrogen reaction, so as to solve the problems raised by the background technology, Summary of the invention

[0005] In view of the shortcomings of the prior art, the present invention aims to provide a MCu X The preparation method and application of the HCP-UiO composite material are simple, cost-effective, environmentally friendly, and easy to promote on a large scale. X The / hcp-UiO composite material has the advantages of high photocatalytic activity and good stability, and can be used for visible light photocatalytic hydrogen production.

[0006] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0007] A MCu X A method for preparing a / hcp-UiO composite material comprises the following steps:

[0008] Step 1: Solvothermal synthesis of ligand L with Cu photosensitizer CuPSs , wherein the mixture is stirred at a constant temperature of 10 to 50° C. for 0.5 to 5 hours before adding (2,2'-bipyridine)-5,5'-dicarboxylic acid, and then reacted at a constant temperature of 10 to 50° C. for 5 to 15 hours after adding (2,2'-bipyridine)-5,5'-dicarboxylic acid;

[0009] Step 2: Use the solvothermal method to synthesize hcp-UiO containing Cu photosensitizer. This step is completed by the solvothermal method in an oven at a constant temperature of 10-150°C for 10-40 hours to obtain Cu x / hcp-UiO;

[0010] Step 3: Using the immersion method in Cu x Metal single atoms are anchored on the surface of / hcp-UiO, wherein the stirring is carried out at a constant temperature of 10 to 50° C. for 2 to 20 hours.

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

[0012] Preferably, CH 2 Cl 2 The volume ratio of DMF is 10:1.

[0013] Preferably, DMF / H 2 The volume ratio of O / FA is: 20:1:5.

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

[0015] 1. The present invention uses solvent thermal and one-step impregnation method to synthesize MCu X / hcp-UiO composite material has excellent photocatalytic activity and stability, and can efficiently decompose water to produce hydrogen under visible light irradiation;

[0016] 2. The preparation method of the present invention is simple to operate, low in cost, environmentally friendly, has no harsh operating environment requirements, and is conducive to large-scale promotion. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0018] Figure 2 hcp-UiO, Pt / hcp-UiO, Cu prepared in Example 1 20 / hcp-UiO and PtCu 20 UV-visible absorption spectrum of / hcp-UiO;

[0019] Figure 3 hcp-UiO, Pt / hcp-UiO, Cu prepared in Examples 1, 2 and 3 20 / hcp-UiO and PtCu 20 Activity comparison of photocatalytic hydrogen production of / hcp-UiO;

[0020] Figure 4 The Cu prepared in Example 1 20 / hcp-UiO、PtCu 20 / hcp-UiO,CuCu 20 / hcp-UiO、CoCu 20 / hcp-UiO、NiCu 20 / hcp-UiO and FeCu 20 Activity comparison of photocatalytic hydrogen production of / hcp-UiO. DETAILED DESCRIPTION

[0021] The following embodiments of the present invention are described in further detail in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0022] like Figures 1 to 3 As shown:

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

[0024] (1) In a pre-dried three-necked round-bottom flask, add tetraacetonitrile copper hexafluorophosphate [Cu(CH 3 CN) 4 ]PF 6 (93 mg, 0.25 mmol) and dimethyl-4,5-bis(diphenylphosphino)xanthine (XantP, 145 mg, 0.25 mol) and 10 mL of dichloromethane (CH 2 Cl 2 ) and stirred under nitrogen atmosphere for 1 hour; (2,2'-bipyridine)-5,5'-dicarboxylic acid (bpydc, 61 mg, 0.25 mmol) in 20 mL CH 2 Cl 2 / DMF (10 / 1, v / v), and stirred for another 6 hours under a nitrogen atmosphere, and the obtained liquid was collected and distilled under reduced pressure to collect the obtained solid;

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

[0026] (3) Pt single atoms were anchored on Cux / hcp-UiO (denoted as: PtCux / hcp-UiO) by impregnation method; 40 mg Cux / hcp-UiO, 20 mg PtCl4, and 10 mL DMF were added to a glass bottle and ultrasonicated for 10 min; then stirred for 10 h; finally, the solid was separated by centrifugation, and then washed with N, N-dimethylformamide (DMF) and ethanol three times each; finally, the collected solid was vacuum dried at 60 °C for 10 h; Cu, Co, Ni, and Fe units were anchored on Cux / hcp-UiO in the same way (denoted as: CuCux / hcp-UiO, CoCux / hcp-UiO, NiCux / hcp-UiO, and FeCux / hcp-UiO, respectively).

[0027] Example 2

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

[0029] 1.0 wt% Pt-loaded Cu20 / hcp-UiO (denoted as 1% Pt Cu20 / hcp-UiO) was prepared by photodeposition. 0.0300 g Cu20 / hcp-UiO was dispersed in 50 mL of solution (50 ml of deionized water and 198 μL of H 2 PtCl 6 The solution (0.08 M) was stirred continuously for 3 h under the irradiation of a 300 W xenon lamp; the product was collected by centrifugation, washed three times with deionized water, and finally dried at 60 ° C for 10 h to obtain 1% Pt Cu 20 / hcp-UiO.

[0030] Application Example 1

[0031] Photocatalytic hydrogen production performance test:

[0032] The hcp-UiO and Cu prepared in Examples 1 and 2 20 / hcp-UiO、PtCu 20 / hcp-UiO, 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 was used for photocatalytic hydrogen production reaction; the reaction was carried out in a closed system, the reactor volume was 100mL, and a 300W xenon lamp was used as the light source; 10mg of sample was weighed and placed in the reactor, 39mL of acetonitrile, 10mL of triethanolamine and 1mL of deionized water were added, ultrasonicated for 10 minutes, high-purity nitrogen was continuously introduced for 10 minutes to exclude air, and then the ventilation valve was closed. After 4h of illumination, quantitative sampling was performed, and gas chromatography and the results were as follows: Figure 3 , 4 ;

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

[0034] From the above, we can see that using light to decompose water to produce hydrogen is not only energy-saving and environmentally friendly, but also in line with the concept of sustainable development; at the same time, the hydrogen generated by the composite material during the catalytic process is a valuable chemical that can be further used in industrial production or other fields. In addition, through performance comparison, it was found that the sample PtCu 20 The photocatalytic hydrogen production performance of / hcp-UiO is much better than that of Cu 20 / hcp-UiO and Pt / hcp-UiO. Description PtCu 20 / hcp-UiO ligand LCu-PSs and L Pt A molecular heterojunction is formed, and the excellent performance comes from L Cu-PSs and L Pt Synergy

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

[0036] From the above, we can see that Pt single atoms have better photocatalytic activity than other metal single atoms.

[0037] In summary, PtCu was synthesized through specific preparation steps. 20 / hcp-UiO composite material, which exhibits high catalytic activity in photocatalytic hydrogen production reaction; experimental results show that the catalytic 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 chemicals such as hydrogen and benzaldehyde, providing new efficient and environmentally friendly solutions for industrial production.

[0038] The embodiments of the present invention are provided for the purpose of illustration and description. Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations of the present invention. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A PtCu 20 A method for preparing a hcp-UiO composite material, characterized in that: The following steps are involved: Synthesis of PtCu composites using a two-step solvothermal and one-step impregnation method 20 / hcp-UiO.

2. A PtCu as claimed in claim 1 20 A method for preparing a hcp-UiO composite material, characterized in that: Solvothermal synthesis of Cu photosensitizer-containing ligand L CuPSs Before adding (2,2'-bipyridine)-5,5'-dicarboxylic acid, stirring is performed at a constant temperature of 10 to 50° C. for 0.5 to 5 hours, and after adding (2,2'-bipyridine)-5,5'-dicarboxylic acid, the reaction is performed at a constant temperature of 10 to 50° C. for 5 to 15 hours.

3. A PtCu as claimed in claim 1 20 A method for preparing a / hcp-UiO composite material, characterized in that Solvothermal synthesis of Cu photosensitizer-containing ligand L CuPSs The solvent was CH2Cl2 / DMF with a volume ratio of 10:

1.

4. A PtCu as claimed in claim 1 20 A method for preparing a hcp-UiO composite material, characterized in that: The hcp-UiO containing Cu photosensitizer was synthesized by solvothermal method. This step was completed by solvothermal method in an oven at 10-150°C for 10-40 hours to obtain Cu. x / hcp-UiO; preferably, the volume ratio of DMF / H2O / FA ​​is: 20:1:

5.

5. A PtCu as claimed in claim 1 20 A method for preparing a hcp-UiO composite material, characterized in that: Using the impregnation method in Cu x Metal single atoms are anchored on the surface of / hcp-UiO, wherein the stirring is carried out at a constant temperature of 10 to 50° C. for 2 to 20 hours.

6. A PtCu prepared by the method of claims 1-5 20 Application of / hcp-UiO composites in photocatalytic hydrogen production.

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