A morphology-controllable graphdiyne two-dimensional metal-organic framework material, a preparation method and application thereof

Abstract

The application discloses a morphology-controllable graphdiyne two-dimensional metal organic framework material and a preparation method and application thereof, a coordination reaction is carried out between a -C=C-C=C- functionalized hydroxyl ligand and a transition metal ion under a solvothermal condition to form a high-crystallinity and high-conjugation graphdiyne two-dimensional MOF; richly embedded acetylene serves as a promising active site to assist photogenerated exciton migration, so that the performance of photocatalytic hydrogen production can be possibly improved; a surfactant CTAB is used to control the morphology to obtain a solid hexagonal prism, a hexagonal flaky structure or a hexagonal prism hollow tube structure material, the material has a high surface volume atom ratio and rich surface modification sites, which helps to reduce diffusion barriers, promote the contact of reactants and active sites, accelerate mass transfer and charge transfer, and further improve the performance of photocatalytic hydrogen production.

Description

Technical Field

[0001] This invention belongs to the technical field of metal-organic framework functional materials, specifically relating to a morphology-controllable graphyne-like two-dimensional metal-organic framework material, its preparation method, and its application. Background Technology

[0002] The extensive use of fossil fuels in modern industry has led to significant environmental problems and an energy crisis. Solar energy is a clean, safe, inexhaustible energy source, making its use as a substitute for fossil fuels and a promising strategy for reducing emissions. To date, several technologies for converting solar energy into electricity, heat, and chemical energy have been reported.

[0003] Since Fujishima first reported the use of TiO2 as a semiconductor for photocatalytic water splitting to produce hydrogen in 1972, photocatalytic hydrogen production from water has attracted strong interest due to the following advantages: 1) Water is the most abundant and cleanest resource on Earth; 2) Hydrogen combustion regenerates water, providing both high energy and environmental friendliness; 3) The widespread use of hydrogen energy will establish a simple and efficient energy cycle for the sustainable development of Earth's civilization in the presence of sunlight and appropriate catalysts. However, finding an efficient catalyst for photocatalytic water splitting is a key factor. Commonly used heterogeneous semiconductor catalysts in photocatalytic hydrogen production include TiO2, CdS, BiVO4, Ta3N5, and g-C3N4, but the inherent defects of inorganic semiconductors themselves result in relatively limited photocatalytic performance.

[0004] Metal-organic frameworks (MOFs) are porous crystalline materials that form an open network structure through coordination bonds between a metal center and multidentate organic ligands. Compared with traditional porous materials (such as zeolites, mesoporous silica, and activated carbon), MOFs possess unique advantages such as high porosity, large specific surface area, well-defined structure, and high tunability, attracting considerable attention and research from scientists in fields such as adsorption, separation, magnetism, hydrogen storage, catalysis, capacitors, and molecular recognition. In recent years, the application of MOFs and their derivatives in photoelectrochemical energy conversion has garnered significant attention due to their unique structure and physicochemical properties.

[0005] However, the limited active sites of traditional MOFs inevitably restrict their application in photocatalysis. Two-dimensional metal-organic frameworks (2D-MOFs) consist of conjugated organic ligands containing polydentate ortho-substituted functional groups (such as -NH2, -OH, -SH, or -SeH) and transition metal ions (such as Cu). 2+ Co 2+ Ni 2+Coordination in a two-dimensional plane forms a network structure with π-d conjugation, promoting strong in-plane conjugation and weak out-of-plane π-π stacking interactions, thus providing an efficient electron transport pathway. 2D-MOFs possess a high surface-to-volume atomic ratio and abundant surface modification sites, which help reduce diffusion barriers, promote contact between reactants and active sites, and accelerate mass and charge transfer. However, the crystallinity and morphology of 2D-MOFs play a crucial role in their electrochemical performance; currently, the preparation of highly crystalline 2D-MOFs with controllable morphology and rich functionality remains a challenge. Summary of the Invention

[0006] Based on the above reasons, the first objective of this invention is to provide a method for preparing a morphology-controllable graphdiyne-like two-dimensional metal-organic framework material. The method involves coordinating a -C≡CC≡C- functionalized hydroxyl ligand with a copper salt under solvothermal conditions, and controlling crystal growth with a surfactant to obtain a morphology-controllable graphdiyne-like two-dimensional metal-organic framework material that exhibits excellent photocatalytic activity.

[0007] The second objective of this invention is to provide a morphology-controllable graphyne-like two-dimensional metal-organic framework material with a highly crystalline and highly conjugated graphyne-like two-dimensional metal-organic framework structure formed by the coordination of hydroxyl ligand diyne groups with metal atoms; promoting d-π orbital hybridization between hydroxyl ligands and transition metal ions, thereby improving its photocatalytic performance.

[0008] The third objective of this invention is to provide a morphology-controllable graphdiyne-like two-dimensional metal-organic framework material for use as a photocatalytic reaction catalyst.

[0009] The first objective of this invention can be achieved by adopting the following technical solution:

[0010] A method for preparing a morphology-controllable graphdiyne-like two-dimensional metal-organic framework material, wherein a monomer with the structure shown in Formula I undergoes a solvothermal reaction with a transition metal ion precursor to obtain a morphology-controllable graphdiyne-like two-dimensional metal-organic framework material with structural units shown in Formula II.

[0011]

[0012] Furthermore, the transition metal ion precursor is Cu. 2+ Co 2+ Ni 2+ Ionic compounds of acetic acid, hydrochloric acid, sulfuric acid or nitric acid and their hydrates.

[0013] Furthermore, the solvothermal reaction is carried out in the presence of a quaternary ammonium salt surfactant; the mass ratio of the quaternary ammonium salt surfactant to the monomer with the structure shown in Formula I is (2-4):1.

[0014] Furthermore, the quaternary ammonium salt surfactant is hexadecyltrimethylammonium bromide; the mass ratio of hexadecyltrimethylammonium bromide to the monomer with the structure shown in Formula I is 2:1 or 4:1.

[0015] Furthermore, the molar ratio of the monomer to the transition metal ion precursor in the structure shown in Formula I is 1:(1.2-2.0).

[0016] Furthermore, the conditions for the solvothermal reaction are:

[0017] The solvent for the reaction is a mixture of DMF and water, wherein the volume ratio of DMF to water is (5-20):1;

[0018] The molar-volume ratio of the monomer to the solvent in the structure shown in Formula I is 1 μmol: (50-200) mL;

[0019] The reaction temperature is 70-100℃; the reaction time is 6-144h.

[0020] Furthermore, the reaction includes a separation and washing process; after separation, the solid is washed with DMF and acetone, and the solid is then Soxhlet extracted in acetone for 1-5 days.

[0021] The second objective of this invention can be achieved by adopting the following technical solution:

[0022] A morphology-controllable graphyne-like two-dimensional metal-organic framework material is prepared by any of the above-described methods for preparing a morphology-controllable graphyne-like two-dimensional metal-organic framework material.

[0023] Furthermore, the graphyne-like two-dimensional metal-organic framework material has a size of 1-20 μm; it is a solid hexagonal prism, a hexagonal sheet structure, or a hexagonal hollow tube structure.

[0024] The third objective of this invention can be achieved by adopting the following technical solution:

[0025] The above-mentioned morphology-controllable graphdiyne-like two-dimensional metal-organic framework material is used as a catalyst for photocatalytic hydrogen production reaction.

[0026] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0027] 1. A method for preparing a morphology-controllable graphdiyne-like two-dimensional metal-organic framework material according to the present invention, wherein -C≡CC≡C- functionalized hydroxyl ligands and transition metal ions undergo coordination reaction under solvothermal conditions to form a highly crystalline and highly conjugated graphdiyne-like two-dimensional MOF.

[0028] 2. The method for preparing a morphology-controllable graphdiyne-like two-dimensional metal-organic framework material of the present invention utilizes the surfactant CTAB and adjusts the growth conditions of MOF, such as reactant ratio, concentration, temperature, and time, to obtain a morphology-controllable graphdiyne-like two-dimensional metal-organic framework material with good photocatalytic activity.

[0029] 3. The present invention provides a morphology-controllable graphdiyne-like two-dimensional metal-organic framework material, in which abundant acetylene is embedded as a promising active site to assist photogenerated exciton migration, thereby potentially improving the performance of photocatalytic hydrogen production; in addition, the morphology control of the metal-organic framework material is achieved through solid hexagonal prisms, hexagonal sheet structures, or hexagonal hollow tube structures; it has a high surface-to-volume atomic ratio and abundant surface modification sites, which helps to reduce diffusion barriers, promote the contact between reactants and active sites, accelerate mass transfer and charge transfer, and further improve the performance of photocatalytic hydrogen production. Attached Figure Description

[0030] Figure 1 Single-crystal X-ray structure simulation was performed on the Cu-L prepared in Example 2;

[0031] Figure 2 The diagram shows the simulated structure of Cu-L AA stack;

[0032] Figure 3 Scanning electron microscope (SEM) images of Cu-L prepared in Example 2 and Cu-L-bulk prepared in Examples 3-5;

[0033] Figure 4 The image is a scanning electron microscope (SEM) image of Cu-L-hollow prepared in Example 6.

[0034] Figure 5 The UV absorption spectrum of Cu-L prepared in Example 2;

[0035] Figure 6 The Mott-Schottky pattern of Cu-L prepared in Example 2;

[0036] Figure 7 The graph shows the photocatalytic hydrogen evolution rate under different catalysts;

[0037] Figure 8 This is a molecular structure diagram of the morphology-controllable two-dimensional metal-organic framework material similar to graphdiyne of the present invention. Detailed Implementation

[0038] The technical solution of the present invention will now be clearly and completely described with reference to specific embodiments. Obviously, the described embodiments are merely some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0039] As catalysts, MOFs have the following significant characteristics: (1) Highly ordered porous structure with uniform pore size distribution and large specific surface area, which is conducive to the dispersion of active components and provides a large number of active sites for catalytic reactions; (2) Controllable pore size: By adjusting the metal center and organic ligand, MOFs materials with pore sizes ranging from micropores to mesopores can be obtained, which is beneficial for preparing complex porous catalysts; (3) Easy to functionalize, which is beneficial for combining MOFs with other functional substances to prepare composite materials and improve the catalytic performance of MOFs themselves; (4) Adjustable metal nodes, which can improve the activity of MOF catalysts while maintaining their original topological structure by changing the type of metal ions. However, the crystallinity and morphology of 2D c-MOFs affect and restrict their photocatalytic performance. At present, there is a lack of preparation methods for morphology-controllable two-dimensional conjugated MOFs, which limits their application in photocatalysis.

[0040] Based on the above, this application provides a morphology-controllable graphdiyne-like two-dimensional metal-organic framework material, its preparation method, and its application.

[0041] A method for preparing a morphology-controllable graphyne-like two-dimensional metal-organic framework material involves a solvothermal reaction of a monomer with the structure shown in Formula I with a transition metal ion precursor to obtain a morphology-controllable graphyne-like two-dimensional metal-organic framework material with structural units shown in Formula II; as shown in Formula II. Figure 8 As shown.

[0042]

[0043] The monomer I-C≡CC≡C-functionalized hydroxyl ligands of Formula I react with transition metal ions under solvothermal conditions. The hydroxyl groups coordinate with the transition metal ions, linking the monomers of Formula I into structural units as shown in Formula II, thus forming a highly crystalline, highly conjugated graphdiyne-like two-dimensional MOF. The abundant acetylene intercalation in the -C≡CC≡C- groups of the monomers of Formula I serves as promising active sites to assist photogenerated exciton migration, potentially improving photocatalytic hydrogen production performance. Furthermore, the π orbitals of the diyne group and the benzene ring in the monomers of Formula I form a conjugated system, which enhances band dispersion and maximizes electron delocalization, further promoting d-π orbital hybridization between the hydroxyl ligands and transition metal ions, thus improving photocatalytic performance. Combined with the high surface-to-volume atomic ratio and abundant surface modification sites of the 2D-MOF itself, which reduces diffusion barriers, promotes contact between reactants and active sites, accelerates mass and charge transfer, and comprehensively improves photocatalytic hydrogen production performance.

[0044] As one embodiment, the transition metal ion precursor is Cu. 2+ Co 2+ Ni 2+ The ions are acetic acid, hydrochloric acid, sulfuric acid, or nitric acid compounds and their hydrates. Copper, cobalt, and nickel are transition metals with excellent catalytic properties. Their metal ions can coordinate with hydroxyl oxygen, and therefore can serve as linking sites to connect the monomers of Formula I to form a two-dimensional MOF. Preferably, the transition metal ion is Cu. 2+ The transition metal ion precursor is copper acetate.

[0045] In one embodiment, the solvothermal reaction is carried out in the presence of a quaternary ammonium salt surfactant. Preferably, the quaternary ammonium salt surfactant is hexadecyltrimethylammonium bromide (CTAB). The addition of the surfactant, wherein the cationic properties and abundant long-chain alkyl chains of the quaternary ammonium salt can regulate the growth and structure formation of the MOF.

[0046] In one embodiment, the mass ratio of the quaternary ammonium salt surfactant to the monomer of Formula I is (2-4):1. Further, the mass ratio of hexadecyltrimethylammonium bromide to the monomer of Formula I is 2:1 or 4:1. The amount of quaternary ammonium salt surfactant added affects the size of the formed MOF crystals. Generally, the addition of quaternary ammonium salt surfactant grows severely packed MOF crystals of varying sizes into micron-sized hexagonal prisms or hexagonal plates, and the crystal size further increases with increasing quaternary ammonium salt surfactant content.

[0047] In one embodiment, the molar ratio of the monomer to the transition metal ion precursor in Formula I is 1:(1.2-2.0). One transition metal ion is coordinated with two hydroxyl oxygen atoms on one phenyl group of the two monomers in Formula I, while the monomer in Formula I has hydroxyl groups attached to three phenyl groups. Therefore, the molar ratio of the monomer to the transition metal ion precursor in Formula I is 1:(1.2-2.0), which ensures the formation of MOF structured materials.

[0048] As one implementation method, the conditions for the solvothermal reaction are:

[0049] The solvent for the reaction is a mixture of DMF and water, wherein the volume ratio of DMF to water is (5-20):1.

[0050] As one embodiment, the molar-volume ratio of the monomer to the solvent in the structure shown in Formula I is 1 μmol:(50-200) mL.

[0051] In one embodiment, the reaction temperature is 70-100℃, and the reaction time is 6-144h. The reaction time also has a certain impact on the MOF structure. In this embodiment, with the same CTAB content, the size of the MOF material gradually increases with the increase of reaction time, and the structure of the MOF material undergoes significant changes after the reaction time reaches a certain duration.

[0052] As one implementation method, the reaction time is within 4 days, and the morphology-controllable graphyne-like two-dimensional metal-organic framework material is a solid hexagonal prism or hexagonal sheet structure.

[0053] As one implementation method, the reaction time is 4-6 days, and the morphology-controllable graphyne-like two-dimensional metal-organic framework material is a hexagonal prism hollow tube structure.

[0054] As one implementation method, the reaction includes a separation and washing process; after separation, the solid is washed with DMF and acetone, and the solid is Soxhlet extracted in acetone for 1-5 days.

[0055] As one embodiment, the monomer with the structure shown in Formula I is prepared via the following reaction pathway:

[0056]

[0057] The present invention also provides a morphology-controllable graphyne-like two-dimensional metal-organic framework material, which is prepared by any of the above-described methods for preparing a morphology-controllable graphyne-like two-dimensional metal-organic framework material.

[0058] In one embodiment, the graphdiyne-like two-dimensional metal-organic framework material has a size of 1-20 μm; it is a solid hexagonal prism, a hexagonal sheet structure, or a hexagonal hollow tube structure. By utilizing the surfactant CTAB and adjusting the growth conditions of the MOF, such as reactant ratio, concentration, temperature, and time, a morphology-controllable graphdiyne-like two-dimensional metal-organic framework material is obtained. This material exhibits hexagonal prism or hollow tubular MOFs with controllable size and morphology, and possesses potential photocatalytic activity.

[0059] This invention also provides an application of a morphology-controllable graphdiyne-like two-dimensional metal-organic framework material as a catalyst for photocatalytic hydrogen production.

[0060] In one implementation, the photocatalytic reaction is carried out in a solution of DMF and water, with 1,3-dimethylbenzimidazole (BIH) as a sacrificial agent, chloroplatinic acid as a co-catalyst, and tris(2,2-bipyridine)ruthenium chloride as a photosensitizer.

[0061] The following is a further explanation using specific embodiments.

[0062] Example 1

[0063] Weigh 0.01 μmol of the monomer and 0.01 μmol of cobalt acetate as shown in Formula I into a glass tube (8 × 150 mm), add 0.42 mL of N,N-dimethylformamide and 0.08 mL of water, and then sonicate the mixture for 10 min. Seal the glass tube with an oxyhydrogen flame and heat it in an oven at 70 °C for 24 h, and then let it cool naturally to room temperature. Collect the crystals by filtration, wash the sample with DMF (5 mL × 5) and acetone (5 mL × 5), then Soxhlet extract it in acetone solution for 3 days, and dry it in vacuum to obtain a morphology-controllable graphdiyne-like two-dimensional metal-organic framework material, named Cu-L.

[0064] Example 2

[0065] Weigh 0.01 μmol of the monomer with the structure shown in Formula I and 0.016 μmol of Cu(NO3)2·3H2O into a glass tube (8×150 mm), add 1 mL of N,N-dimethylformamide and 0.1 mL of water, and then sonicate the mixture for 10 min. Seal the glass tube with an oxyhydrogen flame and heat it in an oven at 85 °C for 48 h, and then let it cool naturally to room temperature. Collect the crystals by filtration, wash the sample with DMF (5 mL×5) and acetone (5 mL×5), then Soxhlet extract it in acetone solution for 3 days, and dry it in vacuum to obtain a morphology-controllable graphdiyne-like two-dimensional metal-organic framework material, named Cu-L.

[0066] Example 3

[0067] Weigh 0.01 μmol of the monomer with the structure shown in Formula I and 0.016 μmol of Cu(NO3)2·3H2O into a glass tube (8×150 mm), add 1 mL of N,N-dimethylformamide and 0.1 mL of water, then add 10 mg of CTAB, and then sonicate the mixture for 10 min. Seal the glass tube with an oxyhydrogen flame and heat it in an oven at 85 °C for 48 h, then let it cool naturally to room temperature. Collect the crystals by filtration, wash the sample with DMF (5 mL×5) and acetone (5 mL×5), then Soxhlet extract it in acetone solution for 3 days, and dry it in vacuum to obtain a morphology-controllable graphdiyne-like two-dimensional metal-organic framework material, named Cu-L-bulk.

[0068] Example 4

[0069] Weigh 0.01 μmol of the monomer with the structure shown in Formula I and 0.016 μmol of Cu(NO3)2·3H2O into a glass tube (8×150 mm), add 1 mL of N,N-dimethylformamide and 0.1 mL of water, then add 20 mg of CTAB, and then sonicate the mixture for 10 min; seal the glass tube with an oxyhydrogen flame and heat it in an oven at 85 °C for 48 h, and then let it cool naturally to room temperature; collect the crystals by filtration, wash the sample with DMF (5 mL×5) and acetone (5 mL×5), then Soxhlet extract it in acetone solution for 3 days, and dry it in vacuum to obtain a morphology-controllable graphdiyne-like two-dimensional metal-organic framework material, named Cu-L-bulk.

[0070] Example 5

[0071] Weigh 0.01 μmol of the monomer with the structure shown in Formula I and 0.016 μmol of Cu(NO3)2·3H2O into a glass tube (8×150 mm), add 1 mL of N,N-dimethylformamide and 0.1 mL of water, then add 20 mg of CTAB, and then sonicate the mixture for 10 min; seal the glass tube with an oxyhydrogen flame and heat it in an oven at 85 °C for 72 h, and then let it cool naturally to room temperature; collect the crystals by filtration, wash the sample with DMF (5 mL×5) and acetone (5 mL×5), then Soxhlet extract it in acetone solution for 3 days, and dry it in vacuum to obtain a morphology-controllable graphdiyne-like two-dimensional metal-organic framework material, named Cu-L-bulk.

[0072] Example 6

[0073] Weigh 0.01 μmol of the monomer with the structure shown in Formula I and 0.016 μmol of Cu(NO3)2·3H2O into a glass tube (8×150 mm), add 1 mL of N,N-dimethylformamide and 0.1 mL of water, then add 20 mg of CTAB, and then sonicate the mixture for 10 min; seal the glass tube with an oxyhydrogen flame and heat it in an oven at 85 °C for 96 h, and then let it cool naturally to room temperature; collect the crystals by filtration, wash the sample with DMF (5 mL×5) and acetone (5 mL×5), then Soxhlet extract it in acetone solution for 3 days, and dry it in vacuum to obtain a morphology-controllable graphdiyne-like two-dimensional metal-organic framework material, named Cu-L-hollow.

[0074] Example 7

[0075] Weigh 0.01 μmol of the monomer with the structure shown in Formula I and 0.012 μmol of NiCl2·6H2O into a glass tube (8×150 mm), add 1.9 mL of N,N-dimethylformamide and 0.1 mL of water, then add 20 mg of CTAB, and then sonicate the mixture for 10 min. Seal the glass tube with an oxyhydrogen flame and heat it in an oven at 100 °C for 144 h, then let it cool naturally to room temperature. Collect the crystals by filtration, wash the sample with DMF (5 mL×5) and acetone (5 mL×5), then Soxhlet extract it in acetone solution for 3 days, and dry it in vacuum to obtain a morphology-controllable graphdiyne-like two-dimensional metal-organic framework material, named Cu-L-hollow.

[0076] Test example:

[0077] (1) Single-crystal X-ray structure simulation was performed on the Cu-L prepared in Example 2; the single-crystal structure is as follows: Figure 1 As shown, the sample before activation is before Soxhlet extraction, and the sample after activation is after Soxhlet extraction; the Cu-L AA stacked simulated structure is shown below. Figure 2 As shown.

[0078] from Figure 1 The results of single-crystal X-ray diffraction tests show that the diffraction pattern of the synthesized Cu-L is highly consistent with the X-ray powder diffraction of the AA stacked structure simulated by MaterialsStudio software in terms of peak position, indicating that the synthesized Cu-L is a two-dimensional layered structure of AA stacking. Moreover, the diffraction pattern also shows that the diffraction peaks of Cu-L are very strong and sharp, indicating that the synthesized metal-organic framework Cu-L has high crystallinity.

[0079] (2) The Cu-L prepared in Example 2, the Cu-L-bulk prepared in Examples 3-5, and the Cu-L-hollow prepared in Example 6 were observed by scanning electron microscopy (SEM). The morphological images are shown below. Figure 3 and Figure 4 As shown, where Figure 3 a represents Cu-L from Example 2; Figure 3 b is the Cu-L-bulk prepared in Example 3; Figure 3 c represents the Cu-L-bulk prepared in Example 4; Figure 3 d represents the Cu-L-bulk prepared in Example 5; Figure 4 The Cu-L-hollow prepared in Example 6.

[0080] from Figure 3 It can be seen that in Example 2, without the addition of CTAB, the prepared Cu-L bulk material exhibited severe accumulation and a blocky shape. However, in Examples 3, 4, and 5, with the addition of CTAB, the morphology changed from severe accumulation and uneven size to Cu-L-bulk with better crystallinity, capable of growing micron-sized hexagonal prisms or hexagonal plates. Furthermore, as the CTAB addition amount in Examples 3 and 4 increased from 10 mg to 20 mg, the size of the Cu-L-bulk increased from 1-5 μm to 5-10 μm. Examples 4 and 5 show that, with the same CTAB addition amount, increasing the hydrothermal reaction time from 2 days to 3 days resulted in a corresponding increase in the size of the Cu-L-bulk, changing from 5-10 μm to 10-20 μm. In particular, when the hydrothermal reaction time was further increased to more than 4 days, a hexagonal hollow tube structure of Cu-L-hollow was obtained. This demonstrates the controllability of morphology by CTAB and reaction time.

[0081] (3) Solid-state UV-Vis absorption testing was performed on the Cu-L prepared in Example 2, and the semiconductor bandgap was measured and the Mott-Schottky spectrum was obtained. The UV absorption spectrum is as follows: Figure 5 As shown; the Mott-Schottky diagram is as follows: Figure 6 As shown.

[0082] from Figure 5 The absorption spectrum test results show that Cu-L exhibits a broad absorption spectrum of 200-2500 nm, covering the visible and near-infrared light range, greatly enhancing the absorption of sunlight. Furthermore, its Eg value is 2.75 eV, possessing a large band gap, which gives it strong electron-hole redox capabilities.

[0083] from Figure 6 The Mott-Schottky spectrum shows that Cu-L has a flat band potential of 0.29 V, indicating that Cu-L has good light absorption capacity and potential photocatalytic hydrogen production capacity.

[0084] Experimental example:

[0085] To investigate the photocatalytic hydrogen production performance of morphology-controllable graphdiyne-like two-dimensional metal-organic framework materials, 3 mg of Cu-L, Cu-L-bulk, and Cu-L-hollow powder samples were dispersed as photocatalysts in 2.5 mL of DMF and 2.5 mL of deionized water, respectively. A certain amount of 1,3-dimethylbenzimidazole (BIH) was added as a sacrificial agent, and a certain amount of chloroplatinic acid was added as a co-catalyst. Ruthenium tris(2,2-bipyridine)chloride was used as a photosensitizer. The system was sealed after purging with argon gas for 30 min. Using an LED lamp as the visible light source, the photocatalytic experiment was conducted for 3 h, followed by manual sample injection. The gas integral area was determined by gas chromatography.

[0086] Under the conditions of 2.5 mL DMF, 2.5 mL H₂O, 3 mg tris(2,2-bipyridine)ruthenium chloride, 5 mg BIH, and 20 μL chloroplatinic acid aqueous solution (5 mg / mL), the photocatalytic hydrogen production rates (HER) of Cu-L, Cu-L-bulk, and Cu-L-hollowde are as follows: Figure 7 As shown.

[0087] from Figure 7 It can be seen that the hydrogen production capacity (HER) of Cu-L photocatalysis is 404 μmol g. -1 h -1 The photocatalytic hydrogen production (HER) of Cu-L-bulk is 544 μmol g. -1 h -1 The photocatalytic hydrogen production (HER) of Cu-L-hollow is 885 μmol g. -1 h -1 This indicates that the morphology-controllable graphdiyne-like two-dimensional metal-organic framework materials of this application have good HER performance, and Cu-L-hollow exhibits the best HER performance due to its higher specific surface area and more exposed active sites.

[0088] In summary, the morphology-controllable graphdiyne-like two-dimensional metal-organic framework (MOF) of this invention involves the coordination reaction of -C≡CC≡C- functionalized hydroxyl ligands with transition metal ion precursors under solvothermal conditions, forming a highly crystalline and highly conjugated graphdiyne-like two-dimensional MOF. The conjugated system formed by the π orbitals of the alkynyl group and the benzene ring enhances band dispersion and maximizes electron delocalization, promoting d-π orbital hybridization between the hydroxyl ligands and transition metal ions, thereby improving its catalytic performance. Furthermore, by utilizing the surfactant CTAB and adjusting the growth conditions of the MOF (reactant ratio, concentration, temperature, time, etc.), a morphology-controllable graphdiyne-like two-dimensional MOF material is obtained. Different morphologies exhibit different HER properties, with the hollow tubular shape showing the highest HER performance.

[0089] The above embodiments are merely preferred embodiments of the present invention and should not be construed as limiting the scope of protection of the present invention. Any non-substantial changes and substitutions made by those skilled in the art based on the present invention shall fall within the scope of protection claimed by the present invention.

Claims

1. A method for preparing a morphology-controllable graphdiyne-like two-dimensional metal-organic framework material, characterized in that, The monomer with the structure shown in Formula I undergoes a solvothermal reaction with a transition metal ion precursor to obtain a graphdiyne-like two-dimensional metal-organic framework material with controllable morphology of the structural unit shown in Formula II. . The transition metal ion precursor is Cu. 2+ Ionic compounds of acetic acid, hydrochloric acid, sulfuric acid or nitric acid and their hydrates; The solvothermal reaction is carried out in the presence of a quaternary ammonium salt surfactant; the mass ratio of the quaternary ammonium salt surfactant to the monomer with the structure shown in Formula I is (2-4):1; The reaction temperature is 70-100℃; the reaction time is 48-144h.

2. The method for preparing a morphology-controllable graphdiyne-like two-dimensional metal-organic framework material according to claim 1, characterized in that, The quaternary ammonium salt surfactant is hexadecyltrimethylammonium bromide; the mass ratio of hexadecyltrimethylammonium bromide to the monomer with the structure shown in Formula I is 2:1 or 4:

1.

3. The method for preparing a morphology-controllable graphdiyne-like two-dimensional metal-organic framework material according to claim 1, characterized in that, The molar ratio of the monomer to the transition metal ion precursor in the structure shown in Formula I is 1:(1.2-2.0).

4. The method for preparing a morphology-controllable graphdiyne-like two-dimensional metal-organic framework material according to claim 1, characterized in that, The conditions for a solvothermal reaction are: The solvent for the reaction is a mixture of DMF and water, wherein the volume ratio of DMF to water is (5-20):1; The molar-volume ratio of the monomer to the solvent in the structure shown in Formula I is 1 μmol: (50-200) mL.

5. The method for preparing a morphology-controllable graphdiyne-like two-dimensional metal-organic framework material according to claim 1, characterized in that, The reaction includes a separation and washing process; after separation, the solid is washed with DMF and acetone, and the solid is then Soxhlet extracted in acetone for 1-5 days.

6. A morphology-controllable graphdiyne-like two-dimensional metal-organic framework material, characterized in that, It is prepared by the method for preparing a morphology-controllable graphdiyne-like two-dimensional metal-organic framework material according to any one of claims 1-5.

7. A morphology-controllable graphdiyne-like two-dimensional metal-organic framework material according to claim 6, characterized in that, The graphyne-like two-dimensional metal-organic framework material has a size of 1-20 μm; it is a solid hexagonal prism, a hexagonal sheet structure, or a hexagonal hollow tube structure.

8. The application of the morphology-controllable graphdiyne-like two-dimensional metal-organic framework material as described in claim 6 or 7 as a catalyst for photocatalytic hydrogen production reaction.

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