Metal organic framework supported catalyst, preparation method and photocatalytic CO2 reduction application

Abstract

The invention belongs to the field of material synthesis catalysis, and provides a metal organic framework supported catalyst, a preparation method and application of the metal organic framework supported catalyst in photocatalytic CO2 reduction. According to the method, a series of metal organic framework supported catalysts are further synthesized by designing a novel picolinamide type organic ligand and are applied to photocatalytic CO2 reduction reaction. The novel picolinamide type organic ligand provided by the invention has the advantage of simplicity and convenience in synthesis, the metal organic framework supported catalyst synthesized by the novel picolinamide type organic ligand has the advantages of novel structure and excellent effect, Ir / Ru metal is introduced to promote the directional movement of electrons in a framework, and the Ir / Ru metal is used as a catalytic center for CO2 reduction to realize the reaction, so that the reaction efficiency is improved. The utilization rate of visible light and the photocatalytic CO2 reduction efficiency are improved.

Description

Technical Field

[0001] The present invention belongs to the field of material synthesis catalysis and relates to a metal organic framework supported catalyst, a preparation method and an application of photocatalytic CO2 reduction. Background Art

[0002] Since the beginning of the 21st century, with the rapid growth of the global economy, energy and environmental issues have become increasingly prominent. However, with the acceleration of industrialization and humanity's overreliance on non-renewable fossil fuels such as coal, oil, and natural gas, atmospheric carbon dioxide concentrations have continued to rise, triggering a chain reaction of rising global temperatures, climate system disruptions, and frequent natural disasters. This crisis has become a serious challenge threatening human sustainable development. Therefore, the search for green, efficient, and renewable energy sources to effectively replace fossil fuels has become a hot topic among scientists. Therefore, developing clean energy alternatives to fossil fuels has become a key path to addressing the energy crisis and environmental challenges. Carbon dioxide, as a C₁ resource with abundant reserves, low cost, and environmental friendliness, offers dual applications in chemical conversion technology. First, by forming chemical bonds such as C₂, C₇, and C₇, it can be used to synthesize high-value-added products (such as urea, carbonates, and salicylic acid, which are used industrially). Second, through photocatalytic / electrical / thermal catalytic reduction technologies, CO₂ can be converted into energy carriers such as CO, formic acid, and methanol, achieving carbon resource recycling while partially replacing traditional fossil fuels and promoting sustainable energy development.

[0003] At the same time, the current global energy system is at a critical stage of transition from fossil fuel dependence to a clean energy-dominated model, and the development of innovative carbon cycle technologies has become a core issue in addressing climate change. Among them, solar-driven CO2 photocatalytic reduction technology is becoming a cutting-edge research direction in the intersection of energy and environment because it can achieve the dual benefits of greenhouse gas resource utilization and storage of intermittent solar energy in the preparation of renewable hydrocarbon fuels. Among them, metal-organic frameworks (MOFs), as crystalline porous materials with precise and controllable structures, provide an ideal platform for constructing multi-component synergistic catalytic systems with their customizable pore microenvironment, programmable active sites and unique confinement effects. Studies have shown that by orderly integrating heterogeneous components such as single-atom catalysts, metal nanoclusters, and quantum dots into the MOFs skeleton, the transmission path of photogenerated carriers can be effectively regulated, the efficiency of interfacial charge separation can be promoted, and the quantum yield and product selectivity of the CO2 photoreduction system can be significantly improved. Among them, Cohen's group carried out post-synthesis exchange in Zr-based UiO-67MOF, introduced Rh-functionalized organic linker Cp*Rh(bpydc)Cl2 (bpydc = 2,2'-bipyridine-5,5'-dicarboxylic acid) to obtain Cp*Rh@UiO-67 catalyst, and applied it to the photocatalytic CO2 reduction reaction to produce formate (ChemsusChem, 2015, 8, 603-608). However, due to the limitations of the post-synthesis exchange method itself, the method is complicated to operate and the amount of Rh-functionalized organic linker introduced cannot be controlled, resulting in the inability to regulate the metal Rh loading in the MOF material, which in turn limits the catalytic activity of the catalyst. Based on this, the present invention is to design MOF materials with organic ligands containing N,N metal coordination sites, further synthesize Cu-based MOF, and introduce iridium / ruthenium metal precursors as catalytic active centers, providing a new method for preparing metal-organic framework-supported catalysts with novel structure, simple synthesis, and easy operation, and providing its application as a catalyst for the photocatalytic carbon dioxide reduction reaction to produce formic acid. Summary of the Invention

[0004] The purpose of the present invention is to achieve functional modification of MOF materials at the molecular level by designing new ligands containing N,N metal coordination sites, synthesizing MOF and further metal functionalization, providing a method for preparing a metal-organic framework-supported catalyst with a novel structure and simple synthesis, and providing its application as a photocatalyst for the reduction of CO2.

[0005] The technical solution of the present invention:

[0006] A metal organic framework supported catalyst, wherein the metal organic framework support has the following structural formula:

[0007]

[0008]

[0009] The metal organic framework supported catalyst has the following structural formula:

[0010]

[0011] A method for preparing a metal organic framework supported catalyst comprises the following steps:

[0012] (1) A pyridine dicarboxylic acid compound is subjected to chlorination treatment and dissolved with 4-aminopyridine in anhydrous tetrahydrofuran, and then reacted in an inert atmosphere at a certain temperature; after the reaction is completed, the solid product is collected by filtration under reduced pressure, and then repeatedly washed with tetrahydrofuran and methanol; finally, the pyridine amide type ligand is obtained by drying under reduced pressure;

[0013] The concentration of 4-aminopyridine is 0.01-0.02 mol / L, and the molar ratio of the pyridine dicarboxylic acid compound to 4-aminopyridine is 1:2-1:4;

[0014] The pyridinedicarboxylic acid compound is 2,5-pyridinedicarboxylic acid or 2,6-pyridinedicarboxylic acid;

[0015] The acyl chloride reagent is thionyl chloride or oxalyl chloride;

[0016] The inert gas is nitrogen or argon;

[0017] The temperature condition is room temperature; the reaction time is 8-24 hours;

[0018] (2) dissolving a pyridine amide ligand, 2-aminoterephthalic acid, and copper nitrate trihydrate in anhydrous N,N-dimethylformamide, and reacting under certain temperature conditions after ultrasonication to form crystals; cooling to room temperature, collecting solid particles by centrifugation, and then repeatedly washing with anhydrous N,N-dimethylformamide and anhydrous methanol, and then soaking in anhydrous methanol; filtering under reduced pressure and drying under vacuum for 48 hours to obtain a Cu metal organic framework support;

[0019] The concentration of the picolinamide ligand is 0.1-0.2 mol / L, the concentration of 2-aminoterephthalic acid is 0.1-0.2 mol / L, and the concentration of copper nitrate trihydrate is 0.1-0.2 mol / L.

[0020] The temperature condition is 110-150°C; the reaction time is 24-75 hours;

[0021] (3) The Cu metal organic framework support and the metal precursor were dissolved in anhydrous methanol and reacted under an inert atmosphere at 65°C for 24 hours; after cooling to room temperature, the solid particles were collected by centrifugation and then repeatedly washed with anhydrous methanol; the solid particles were filtered under reduced pressure and dried under vacuum for 48 hours to obtain a metal organic framework supported catalyst.

[0022] Wherein, the metal precursor is dichloro(pentamethylcyclopentadiene)iridium(III) dimer or dichlorodicarbonylruthenium polymer, the concentration of the metal precursor is 0.005-0.01 mol / L, and the molar ratio of the Cu metal organic framework support to the metal precursor is 4:1-2:1;

[0023] The inert atmosphere is nitrogen or argon.

[0024] A method for photocatalytic CO2 reduction using a metal organic framework-supported catalyst comprises the following steps:

[0025] (1) Photocatalytic CO2 reduction to formic acid: Under an inert atmosphere, a metal organic framework-supported catalyst and a sacrificial agent are dispersed in a solvent, which is then replaced with carbon dioxide multiple times. The solvent is then placed in a photochemical reactor and stirred for 2.0-12 hours.

[0026] The sacrificial agent is one of 1,3-dimethyl-2-phenyl-2,3-dihydro-1H-benzo[d]imidazole (BIH), 1-benzyl-1,4-dihydronicotinamide (BNAH), triethanolamine (TEOA), and triethylamine (TEA);

[0027] The concentration of the sacrificial agent is 0.004-0.016 mol / L, and the molar ratio of the metal organic framework supported catalyst to the sacrificial agent is 1:2-1:50;

[0028] The solvent is one of anhydrous acetonitrile, a mixed solution of acetonitrile and water in a volume ratio of 1:1-29:1, anhydrous N,N-dimethylformamide (DMF), a mixed solution of N,N-dimethylformamide and water in a volume ratio of 1:1-29:1, anhydrous N,N-dimethylacetamide (DMA), a mixed solution of N,N-dimethylacetamide and water in a volume ratio of 1:1-29:1, and water;

[0029] The inert atmosphere is nitrogen or argon;

[0030] The photochemical reactor is a photochemical reactor equipped with a Xe lamp or a parallel photochemical reactor equipped with an LED light source;

[0031] The reduction product is formate.

[0032] (2) Determination of formic acid / formate: After the reaction is completed, the reaction solution is removed from the reaction tube and filtered with an organic filter membrane. All solvents are removed by distillation under reduced pressure. After the volume is fixed with ultrapure water, ion chromatography is performed to determine the concentration of formic acid / formate based on the peak area and the formic acid standard curve.

[0033] (3) Catalytic activity of catalyst m Measurement: A measure of the catalytic activity of heterogeneous photocatalytic CO2 reduction, usually the amount of substance that can be catalyzed to produce products per gram of catalyst per unit time.

[0034] Calculation formula:

[0035]

[0036] Conc.(HCOO-): concentration of formic acid / formate produced, mol / L;

[0037] V(HCOO-): volume of the solution after reaction, L;

[0038] m(Cat.): mass of catalyst used, g;

[0039] t: reaction time, h.

[0040] The beneficial effects of the present invention are as follows: the novel pyridineamide-type complex provided by the present invention is easy to prepare, and the metal-organic framework-loaded catalyst prepared therefrom has the advantages of novel structure, excellent performance, and easy preparation; by designing an organic ligand with a pyridineamide-type N,N bidentate coordination site, Ir / Ru metal is further loaded onto the metal-organic framework carrier, promoting the directional movement of electrons within the framework, and serving as a catalytic center for CO2 reduction to realize the reaction, thereby improving the utilization rate of visible light and the CO2 photocatalytic efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 The pyridine amide type complex 2 prepared in Example 3 of the present invention 1 H NMR spectrum.

[0042] Figure 2 3 are X-ray diffraction (XRD) spectra of Cu-MOF-2 and Ir@Cu-MOF-2 prepared in Example 3 of the present invention.

[0043] Figure 3 This is a field emission scanning electron microscope (SEM) spectrum of Ir@Cu-MOF-2 prepared in Example 3 of the present invention.

[0044] Figure 4 It is the solid ultraviolet visible diffuse reflectance (UV-vis DRS) spectra of Cu-MOF-2 and Ir@Cu-MOF-2 prepared in Example 3 of the present invention.

[0045] Figure 5 It is a comparison chart of the catalytic activities of the four catalysts in Examples 1-4 of the present invention under the same reaction conditions. DETAILED DESCRIPTION

[0046] The specific implementation of the present invention is further described below in conjunction with the accompanying drawings and technical solutions.

[0047] Example 1

[0048] Preparation of Ir@Cu-MOF-1 and its application in photocatalytic CO2 reduction

[0049] (1) Dissolve 2,5-pyridinedicarboxylic acid (500.0 mg, 3 mmol) in 10 mL of dimethyl sulfoxide, add 1 drop of N,N-dimethylformamide, and react at room temperature for 12 h in an inert atmosphere. After the reaction, evaporate under reduced pressure, dissolve in anhydrous and oxygen-free tetrahydrofuran, and add triethylamine (101 μL, 1 mmol).

[0050] 4-Aminopyridine (564 mg, 6 mmol) was dissolved in 10 mL of anhydrous tetrahydrofuran and slowly added dropwise to the reaction product under an inert gas atmosphere in an ice-water bath. After the addition was complete, the reaction was allowed to proceed at room temperature under an inert atmosphere for 12 h. Upon completion of the reaction, the solid product was collected by filtration under reduced pressure and subsequently washed with tetrahydrofuran and methanol, respectively. Finally, the product was dried under reduced pressure to yield 864.2 mg of pyridineamide complex 1, with a yield of 81.2%.

[0051] (2) Complex 1 (319 mg, 1 mmol), 2-aminoterephthalic acid (181 mg, 1 mmol) and copper nitrate trihydrate (242 mg, 1 mmol) were dissolved in 15 mL of N,N-dimethylformamide. After ultrasonication for 30 min, the solution was transferred to a 50 mL polytetrafluoroethylene-lined container, sealed in a hydrothermal autoclave, and then placed in a 120°C oven for 75 h. After the reaction was completed, the mixture was naturally cooled to room temperature and washed with N,N-dimethylformamide and methanol by centrifugation. The solid particles were collected and filtered under reduced pressure. The product was placed in a vacuum oven at 80°C and dried for 24 h to obtain the product Cu-MOF-1 with a yield of 312.6 mg.

[0052] (3) The prepared Cu-MOF-1 (258.5 mg, 0.3 mmol) and dichloro(pentamethylcyclopentadiene)iridium(III) dimer ([Cp*IrCl2]2) (59.8 mg, 0.075 mmol) were dissolved in 15 mL of anhydrous MeOH. After N2 displacement three times, the mixture was heated to 65°C and reacted for 24 h. After cooling to room temperature, the solid particles were collected by centrifugation and then repeatedly washed with anhydrous MeOH. The final product was filtered under reduced pressure, placed in a vacuum oven at 80°C, and vacuum dried for 24 h to obtain Ir@Cu-MOF-1 with a yield of 241.1 mg.

[0053] (4) Under N2 protection, an acetonitrile / water mixture (15 mL, v / v = 14:1) was added to the photoreaction tube. Then, Ir@Cu-MOF-1 (10 mg) and BIH (30 mg, 0.134 mmol) were added to the photoreaction tube and the tube was sealed. The reaction was replaced with high-purity CO2 three times for 30 min. Finally, the reaction tube was placed in a parallel photoreactor with an 18 W LED light source (λ ≥ 420 nm) and stirred at room temperature for 8 h to produce 12.4 μmol of formic acid. The catalyst activity was 155.2 μmol·g -1 ·h -1 .

[0054] Example 2

[0055] Preparation of Ru@Cu-MOF-1 and its application in photocatalytic CO2 reduction

[0056] (1) The preparation process of Cu-MOF-1 is the same as step (1) and step (2) of Example 1.

[0057] (2) The prepared Cu-MOF-1 (258.5 mg, 0.3 mmol), dichlorodicarbonylruthenium polymer ([RuCl2(CO)2] n ) (34.2 mg, 0.15 mmol) was dissolved in 15 mL of anhydrous MeOH. After nitrogen displacement three times, the mixture was heated to 65°C and reacted for 24 h. After cooling to room temperature, the solid particles were collected by centrifugation and repeatedly washed with anhydrous MeOH. The final product was filtered under reduced pressure, placed in a vacuum oven at 80°C, and dried for 24 h to obtain Ru@Cu-MOF-1 in a yield of 254.2 mg.

[0058] (3) Under N2 protection, an acetonitrile / water mixture (15 mL, v / v = 14:1) was added to the photoreaction tube, followed by the addition of Ru@Cu-MOF-1 (10 mg) and BIH (30 mg, 0.134 mmol) to the photoreaction tube, which was then sealed. The reaction tube was replaced with high-purity CO2 three times, and then continued for 30 min. Finally, the reaction tube was placed in a parallel photoreactor equipped with an 18 W LED light source (λ ≥ 420 nm) and stirred at room temperature for 8 h to produce 11.8 μmol of formic acid. The catalyst activity was 147.3 μmol·g -1 ·h -1 .

[0059] Example 3

[0060] Preparation of Ir@Cu-MOF-2 and its application in photocatalytic CO2 reduction

[0061] (1) Dissolve 2,6-pyridinedicarboxylic acid (500.0 mg, 3 mmol) in 10 mL of dimethyl sulfoxide, add 1 drop of N,N-dimethylformamide, and react at room temperature for 12 h in an inert atmosphere. After the reaction, evaporate under reduced pressure, dissolve in anhydrous and oxygen-free tetrahydrofuran, and add triethylamine (101 μL, 1 mmol).

[0062] 4-Aminopyridine (564 mg, 6 mmol) was dissolved in 10 mL of anhydrous tetrahydrofuran and slowly added dropwise to the reaction product under an inert gas atmosphere in an ice-water bath. After the addition was complete, the reaction was allowed to proceed at room temperature under an inert atmosphere for 12 h. After the reaction was complete, the solid product was collected by filtration under reduced pressure and then washed with tetrahydrofuran and methanol, respectively. Finally, the product was dried under reduced pressure to obtain 922.1 mg of the pyridineamide complex 2, yielding 86.7%.

[0063] (2) Complex 2 (319 mg, 1 mmol), 2-aminoterephthalic acid (181 mg, 1 mmol) and copper nitrate trihydrate (262 mg, 1 mmol) were dissolved in 15 mL N,N-dimethylformamide. After ultrasonication for 30 min, the solution was transferred to a 50 mL polytetrafluoroethylene-lined container, sealed in a hydrothermal autoclave, and then placed in a 120°C oven for 75 h. After the reaction was completed, the mixture was naturally cooled to room temperature and washed with N,N-dimethylformamide and methanol by centrifugation. The solid particles were collected and filtered under reduced pressure. The product was placed in a vacuum oven at 80°C and dried for 24 h to obtain the product Cu-MOF-2 with a yield of 298.5 mg.

[0064] (3) The prepared Cu-MOF-2 (258.5 mg, 0.3 mmol) and dichloro(pentamethylcyclopentadiene)iridium(III) dimer ([Cp*IrCl2]2) (59.8 mg, 0.075 mmol) were dissolved in 15 mL of anhydrous MeOH. After N2 displacement three times, the mixture was heated to 65°C and reacted for 24 h. After cooling to room temperature, the solid particles were collected by centrifugation and then repeatedly washed with anhydrous MeOH. The final product was filtered under reduced pressure, placed in a vacuum oven at 80°C, and dried for 24 h to obtain Ir@Cu-MOF-2 with a yield of 247.3 mg.

[0065] (4) Under N2 protection, an acetonitrile / water mixture (15 mL, v / v = 14:1) was added to the photoreaction tube. Then, Ir@Cu-MOF-2 (10 mg) and BIH (30 mg, 0.134 mmol) were added to the photoreaction tube and the tube was sealed. The reaction was replaced with high-purity CO2 three times for 30 min. Finally, the reaction tube was placed in a parallel photoreactor with an 18 W LED light source (λ ≥ 420 nm) and stirred at room temperature for 8 h to produce 22.8 μmol of formic acid. The catalyst activity was 285.4 μmol·g -1 ·h -1 .

[0066] Example 4

[0067] Preparation of Ru@Cu-MOF-2 and its application in photocatalytic CO2 reduction

[0068] (1) The preparation process of Cu-MOF-2 is the same as step (1) and step (2) of Example 3.

[0069] (2) The prepared Cu-MOF-2 (258.5 mg, 0.3 mmol), dichlorodicarbonylruthenium polymer ([RuCl2(CO)2] n ) (34.2 mg, 0.15 mmol) was dissolved in 15 mL of anhydrous MeOH. After nitrogen displacement three times, the mixture was heated to 65°C and reacted for 24 h. After cooling to room temperature, the solid particles were collected by centrifugation and repeatedly washed with anhydrous MeOH. The final product was filtered under reduced pressure, placed in a vacuum oven at 80°C, and dried for 24 h to obtain Ru@Cu-MOF-2 in a yield of 255.4 mg.

[0070] (3) Under N2 protection, an acetonitrile / water mixture (15 mL, v / v = 14:1) was added to the photoreaction tube. Then, Ru@Cu-MOF-2 (10 mg) and BIH (30 mg, 0.134 mmol) were added to the photoreaction tube and the tube was sealed. The reaction was replaced with high-purity CO2 three times and then continued for 30 min. Finally, the reaction tube was placed in a parallel photoreactor with an 18 W LED light source (λ ≥ 420 nm) and stirred at room temperature for 8 h to produce 16.9 μmol of formic acid. The catalyst activity was 211.2 μmol·g -1 ·h -1 .

[0071] Example 5

[0072] Preparation of Ir@Cu-MOF-2 and its application in photocatalytic CO2 reduction

[0073] (1) Dissolve 2,6-pyridinedicarboxylic acid (500 mg, 3 mmol) in 10 mL of dimethyl sulfoxide, add 1 drop of N,N-dimethylformamide, and react at room temperature in an inert atmosphere for 12 h. After the reaction, evaporate under reduced pressure, dissolve in anhydrous and oxygen-free tetrahydrofuran, and add triethylamine (101 μL, 1 mmol).

[0074] 4-Aminopyridine (564 mg, 3 mmol) was dissolved in 10 mL of anhydrous tetrahydrofuran and slowly added dropwise to the reaction product under an inert gas atmosphere in an ice-water bath. After the addition was complete, the reaction was allowed to proceed at room temperature under an inert atmosphere for 12 h. Upon completion of the reaction, the solid product was collected by filtration under reduced pressure and subsequently washed with tetrahydrofuran and methanol, respectively. Finally, the product was dried under reduced pressure to yield 922.1 mg of pyridineamide complex 2, with a yield of 86.7%.

[0075] (2) Complex 2 (319 mg, 1 mmol), 2-aminoterephthalic acid (181 mg, 1 mmol) and copper nitrate trihydrate (262 mg, 1 mmol) were dissolved in 15 mL N,N-dimethylformamide. After ultrasonication for 30 min, the solution was transferred to a 50 mL polytetrafluoroethylene-lined container, sealed in a hydrothermal autoclave, and then placed in an oven at 120°C for 24 h. After the reaction was completed, the mixture was naturally cooled to room temperature and washed with N,N-dimethylformamide and methanol by centrifugation. The solid particles were collected and filtered under reduced pressure. The product was placed in a vacuum oven at 80°C and dried for 24 h to obtain the product Cu-MOF-2 with a yield of 119.4 mg.

[0076] (3) The prepared Cu-MOF-2 (258.5 mg, 0.3 mmol) and dichloro(pentamethylcyclopentadiene)iridium(III) dimer ([Cp*IrCl2]2) (59.8 mg, 0.075 mmol) were dissolved in 15 mL of anhydrous MeOH. After N2 displacement three times, the mixture was heated to 65°C and reacted for 24 h. After cooling to room temperature, the solid particles were collected by centrifugation and then repeatedly washed with anhydrous MeOH. The final product was filtered under reduced pressure, placed in a vacuum oven at 80°C, and dried for 24 h to obtain Ir@Cu-MOF-2 with a yield of 247.3 mg.

[0077] (4) Under N2 protection, an acetonitrile / water mixture (15 mL, v / v = 14:1) was added to the photoreaction tube. Then, Ir@Cu-MOF-2 (10 mg) and BIH (30 mg, 0.134 mmol) were added to the photoreaction tube and the tube was sealed. The reaction was replaced with high-purity CO2 three times for 30 min. Finally, the reaction tube was placed in a parallel photoreactor with an 18 W LED light source (λ ≥ 420 nm) and stirred at room temperature for 8 h to produce 22.8 μmol of formic acid. The catalyst activity was 285.4 μmol·g -1 ·h -1 .

[0078] Example 6

[0079] Preparation of Ir@Cu-MOF-2 and its application in photocatalytic CO2 reduction

[0080] (1) Dissolve 2,6-pyridinedicarboxylic acid (1000 mg, 6 mmol) in 10 mL of dimethyl sulfoxide, add 1 drop of N,N-dimethylformamide, and react at room temperature for 12 h in an inert atmosphere. After the reaction, evaporate under reduced pressure, dissolve in anhydrous and oxygen-free tetrahydrofuran, and add triethylamine (101 μL, 2 mmol).

[0081] 4-Aminopyridine (1128 mg, 6 mmol) was dissolved in 20 mL of anhydrous tetrahydrofuran and slowly added dropwise to the reaction product under an inert gas atmosphere in an ice-water bath. After the addition was complete, the reaction was allowed to proceed at room temperature under an inert atmosphere for 12 h. Upon completion of the reaction, the solid product was collected by filtration under reduced pressure and subsequently washed with tetrahydrofuran and methanol, respectively. Finally, the product was dried under reduced pressure to obtain 1857.74 mg of the pyridineamide complex 2, yielding 87.3%.

[0082] (2) Complex 2 (319 mg, 1 mmol), 2-aminoterephthalic acid (181 mg, 1 mmol) and copper nitrate trihydrate (262 mg, 1 mmol) were dissolved in 15 mL N,N-dimethylformamide. After ultrasonication for 30 min, the solution was transferred to a 50 mL polytetrafluoroethylene-lined container, sealed in a hydrothermal autoclave, and then placed in a 120°C oven for 75 h. After the reaction was completed, the mixture was naturally cooled to room temperature and washed with N,N-dimethylformamide and methanol by centrifugation. The solid particles were collected and filtered under reduced pressure. The product was placed in a vacuum oven at 80°C and dried for 24 h to obtain the product Cu-MOF-2 with a yield of 247.3 mg.

[0083] (3) The prepared Cu-MOF-2 (258.5 mg, 0.3 mmol) and dichloro(pentamethylcyclopentadiene)iridium(III) dimer ([Cp*IrCl2]2) (59.8 mg, 0.075 mmol) were dissolved in 15 mL of anhydrous MeOH. After N2 displacement three times, the mixture was heated to 65°C and reacted for 24 h. After cooling to room temperature, the solid particles were collected by centrifugation and then repeatedly washed with anhydrous MeOH. The final product was filtered under reduced pressure, placed in a vacuum oven at 80°C, and dried for 24 h to obtain Ir@Cu-MOF-2 with a yield of 247.3 mg.

[0084] (4) Under N2 protection, an acetonitrile / water mixture (15 mL, v / v = 14:1) was added to the photoreaction tube. Then, Ir@Cu-MOF-2 (10 mg) and BIH (30 mg, 0.134 mmol) were added to the photoreaction tube and the tube was sealed. The reaction was replaced with high-purity CO2 three times for 30 min. Finally, the reaction tube was placed in a parallel photoreactor with an 18 W LED light source (λ ≥ 420 nm) and stirred at room temperature for 8 h to produce 22.8 μmol of formic acid. The catalyst activity was 285.4 μmol·g -1 ·h -1 .

Claims

1. A metal organic framework supported catalyst, characterized in that The structural formula of the metal organic framework support in the metal organic framework supported catalyst is as follows: The structural formula of the metal organic framework supported catalyst is as follows:

2. A method for preparing a metal organic framework supported catalyst, characterized in that: The following steps are involved: (1) A pyridine dicarboxylic acid compound is subjected to chlorination treatment and dissolved with 4-aminopyridine in anhydrous tetrahydrofuran, and then reacted in an inert atmosphere at a certain temperature; after the reaction is completed, the solid product is collected by filtration under reduced pressure, and then repeatedly washed with tetrahydrofuran and methanol; finally, the pyridine amide type ligand is obtained by drying under reduced pressure; (2) dissolving a pyridine amide ligand, 2-aminoterephthalic acid, and copper nitrate trihydrate in anhydrous N,N-dimethylformamide, and reacting under certain temperature conditions after ultrasonication to form crystals; cooling to room temperature, collecting solid particles by centrifugation, and then repeatedly washing with anhydrous N,N-dimethylformamide and anhydrous methanol, and then soaking in anhydrous methanol; filtering under reduced pressure and drying under vacuum for 48 hours to obtain a Cu metal organic framework support; (3) The Cu metal organic framework support and the metal precursor were dissolved in anhydrous methanol and reacted under an inert atmosphere at 65°C for 24 hours; after cooling to room temperature, the solid particles were collected by centrifugation and then repeatedly washed with anhydrous methanol; the solid particles were filtered under reduced pressure and dried under vacuum for 48 hours to obtain a metal organic framework supported catalyst.

3. The preparation method according to claim 2, characterized in that In step (1), The concentration of the 4-aminopyridine is 0.01 to 0.02 mol / L, and the molar ratio of the pyridine dicarboxylic acid compound to the 4-aminopyridine is 1:2 to 1:4; The pyridinedicarboxylic acid compound is 2,5-pyridinedicarboxylic acid or 2,6-pyridinedicarboxylic acid; The acyl chloride reagent is thionyl chloride or oxalyl chloride; The inert gas is nitrogen or argon; The temperature condition is room temperature; the reaction time is 8-24 hours.

4. The preparation method according to claim 2, characterized in that In step (2), The concentration of the picolinamide ligand is 0.1-0.2 mol / L, the concentration of 2-aminoterephthalic acid is 0.1-0.2 mol / L, and the concentration of copper nitrate trihydrate is 0.1-0.2 mol / L; The temperature condition is 110-150° C.; and the reaction time is 24-75 hours.

5. The preparation method according to claim 2, characterized in that In step (3), The metal precursor is dichloro(pentamethylcyclopentadiene)iridium(III) dimer or dichlorodicarbonylruthenium polymer, the concentration of the metal precursor is 0.005-0.01 mol / L, and the molar ratio of the Cu metal organic framework support to the metal precursor is 4:1-2:1; The inert atmosphere is nitrogen or argon.

6. A method for photocatalytic CO2 reduction using a metal organic framework supported catalyst, characterized in that: Here are the steps: Photocatalytic CO2 reduction to produce formic acid: Under an inert atmosphere, the metal organic framework-supported catalyst and sacrificial agent are dispersed in a solvent, then replaced with carbon dioxide multiple times, and finally placed in a photochemical reactor and stirred for 2.0-12 hours.

7. The method according to claim 6, characterized in that The sacrificial agent is one of 1,3-dimethyl-2-phenyl-2,3-dihydro-1H-benzo[d]imidazole (BIH), 1-benzyl-1,4-dihydronicotinamide, triethanolamine, and triethylamine; The concentration of the sacrificial agent is 0.004-0.016 mol / L, and the molar ratio of the metal organic framework supported catalyst to the sacrificial agent is 1:2-1:50; The solvent is selected from the group consisting of anhydrous acetonitrile, a mixed solution of acetonitrile and water in a volume ratio of 1:1-29:1, anhydrous N,N-dimethylformamide, a mixed solution of N,N-dimethylformamide and water in a volume ratio of 1:1-29:1, anhydrous N,N-dimethylacetamide, a mixed solution of N,N-dimethylacetamide and water in a volume ratio of 1:1-29:1, and water; The inert atmosphere is nitrogen or argon; The photochemical reactor is a photochemical reactor equipped with a Xe lamp or a parallel photochemical reactor equipped with an LED light source.

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