A "core-satellite" structured MOF-on-MOF photocatalyst and preparation method and application thereof

Abstract

A "core-satellite" structured MOF-on-MOF photocatalyst, its preparation method, and its application belong to the field of photocatalysis technology. The structure of the "core-satellite" structured MOF-on-MOF photocatalyst includes: a visible-light-responsive Ti-MOF as a support (core), the Ti-MOF being one of MIL-125 with a disc-shaped, rhombic dodecahedral, or truncated octahedral morphology, and UiO-66 nanoparticles (satellites) grown in situ around the Ti-MOF. The "core-satellite" structured MOF-on-MOF photocatalyst obtained by this invention has a large specific surface area and excellent CO2 adsorption capacity. Simultaneously, the constructed heterostructure achieves efficient separation of photogenerated electrons and holes, exhibiting excellent photocatalytic CO2 reduction activity.

Description

Technical Field

[0001] This invention relates to the field of photocatalyst technology, and particularly to a "core-satellite" structure MOF-on-MOF photocatalyst, its preparation method and application, specifically to a MIL-125@UiO-66 catalyst with a "core-satellite" structure. Background Technology

[0002] The rapid growth of the global population and the rapid development of modern industry have led to a high dependence on the combustion of fossil fuels, resulting in a significant increase in atmospheric CO2 concentration and triggering a series of global problems such as global warming, sea-level rise, and resource shortages. Considering the inexhaustible nature of solar energy, utilizing CO2 to produce valuable chemicals with the aid of catalysts can simultaneously reduce the greenhouse effect and alleviate energy shortage pressures. Therefore, novel and highly efficient photocatalysts are constantly emerging. Currently, a series of strategies have been proposed to improve the photocatalytic performance of semiconductors, including functionalized surface modification, metal ion doping, and single-atom catalysis. However, the photocatalytic activity of these catalysts still falls far short of practical applications and fails to meet the demands. Therefore, there is an urgent need to design highly efficient, stable, and unique heterojunction photocatalysts.

[0003] Metal-organic frameworks (MOFs) are a unique class of porous crystalline materials with a periodic network structure, composed of metal nodes (metal ions / clusters) and organic ligands interconnected through self-assembly. Due to their high porosity, high specific surface area, and regular channel structure, MOFs have demonstrated excellent performance in numerous fields such as gas adsorption and separation, sensors, drug delivery, and heterogeneous catalysis. Compared to traditional photocatalytic materials, MOFs offer the following advantages: highly tunable metal nodes and organic linkers allow for precise design of band gaps, catalytically active sites, and efficient charge transfer pathways; the pores of MOFs can be endowed with tunable pore size and surface chemistry, facilitating the rational design of highly efficient MOF-based photocatalysts with enhanced CO2 capture capabilities; and the customizable nature of MOFs, comprised of the availability of various organic ligands and the rich coordination chemistry of transition metal cations, provides significant flexibility for successfully adjusting light absorption to achieve efficient solar energy utilization. However, most individual MOFs have relatively wide band gaps, resulting in low utilization of visible light, and high recombination rates of photogenerated electron-hole pairs, which greatly limit their catalytic activity. On the other hand, the combination of two or more different MOFs as a new generation of complex MOF hybrids has attracted great interest in the development of nanomaterial structures. MOF-on-MOF structures can effectively promote charge separation and carrier transfer, and significantly improve photocatalytic activity. In addition to porosity and stability, these hybrid nanomaterials can also ensure the opposite migration of electrons and holes through the conduction and valence bands. This novel hybrid nanomaterial offers more possibilities for structure and function tuning, and better maintains large surface area, inherent porosity, and high crystallinity. Therefore, MOF-on-MOF photocatalysts are of great value for meeting future practical applications. Summary of the Invention

[0004] The purpose of this invention is to provide a "core-satellite" structured MOF-on-MOF photocatalyst, its preparation method, and its application. This invention organically integrates the advantages of two single MOF materials. First, MIL-125 with disc-shaped, rhombic dodecahedral, or truncated octahedral morphologies is prepared as the core. Then, multiple UiO-66 nanoparticles are grown in situ on the surface of MIL-125 as satellites, forming MOF-on-MOFs with different "core-satellite" heterojunction structures. The constructed heterojunction structures achieve efficient separation of photogenerated electron-hole pairs through contact at different crystal plane interfaces. While the separation effect of electron-hole pairs varies, all effectively overcome the shortcomings of single MOFs, such as narrow photoresponse range and high carrier recombination rate.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] One of the technical solutions of this invention is to provide a "core-satellite" structure MOF-on-MOF photocatalyst, the structure of which includes: a Ti-MOF with visible light response as a support, i.e., a core, wherein the Ti-MOF is one of MIL-125 with a disc-shaped, rhombic dodecahedral or truncated octahedral shape, and multiple UiO-66 nanoparticles are grown in situ on the surface of the Ti-MOF as satellites surrounding the core support.

[0007] The second technical solution of this invention provides a method for preparing the above-mentioned "nuclear-satellite" structure MOF-on-MOF photocatalyst, comprising the following steps:

[0008] (1) Preparation of Ti-MOF with visible light response;

[0009] (2) Ti-MOF and polyvinylpyrrolidone were dispersed in N,N-dimethylformamide solution and soaked; metal salt and ligands that form UiO-66 nanoparticles were added, and after the reaction was completed, MOF-on-MOF photocatalyst with "nuclear-satellite" structure was obtained.

[0010] The preparation steps of Ti-MOF in step (1) include the following:

[0011] (a) Preparation of disc-shaped MIL-125: Titanium salt and ligand were dissolved in a mixed solution of N,N-dimethylformamide and methanol. After the reaction was completed, MIL-125 with a disc-shaped morphology was obtained.

[0012] (b) Preparation of MIL-125 with rhombic dodecahedral morphology: Titanium salt and ligand were dissolved in a mixed solution of N,N-dimethylformamide, methanol and acetic acid. After the reaction was completed, MIL-125 with rhombic dodecahedral morphology was obtained.

[0013] (c) Preparation of MIL-125 with truncated octahedral morphology: Titanium salt and ligand were dissolved in a mixed solution of N,N-dimethylformamide, methanol and acetic acid. After the reaction was completed, MIL-125 with truncated octahedral morphology was obtained.

[0014] Preferably, the titanium salt in steps (a), (b), and (c) is tetrabutyl titanate, and the ligand is one of unsubstituted terephthalic acid or terephthalic acid with mono- or poly-substituted substituents, wherein the substituent is selected from any one of amino, carboxyl, hydroxyl, or halogen; the volume ratio of N,N-dimethylformamide to methanol in step (a) is (8-10):(0.5-2); the volume ratio of N,N-dimethylformamide to methanol to acetic acid in step (b) is (8-10):(0.5-2):(0.2-0.4); and the volume ratio of N,N-dimethylformamide to methanol to acetic acid in step (c) is (8-10):(0.5-2):(0.7-0.9). Each 0.1 mL-0.5 mL of tetrabutyl titanate in steps (a), (b), and (c) corresponds to a volume of 7-9.5 mL of N,N-dimethylformamide.

[0015] More preferably, the ligand described in steps (a), (b), and (c) is 2-aminoterephthalic acid;

[0016] Preferably, in step (a), the molar ratio of titanium salt to ligand is 5:1 to 1:5; in step (b), the molar ratio of titanium salt to ligand is 10:1 to 1:10; and in step (c), the molar ratio of titanium salt to ligand is 5:1 to 1:5.

[0017] More preferably, in step (a), the molar ratio of titanium salt to ligand is 5:3; in step (b), the molar ratio of titanium salt to ligand is 10:7; and in step (c), the molar ratio of titanium salt to ligand is 5:3.

[0018] Preferably, the reaction temperature in steps (a), (b), and (c) is 120-180°C, and the reaction time is 12-36 hours.

[0019] More preferably, the reaction temperature in steps (a), (b), and (c) is 150°C and the reaction time is 24 hours;

[0020] Preferably, in step (2), the molar ratio of Ti-MOF to polyvinylpyrrolidone is 10:1 to 1:10; the soaking time is 1 to 3 hours; the metal salt is zirconium salt; the ligand is one of unsubstituted terephthalic acid or terephthalic acid with mono- or poly-substituted substituents, wherein the substituent is selected from any one of amino, carboxyl, hydroxyl or halogen; the molar ratio of metal salt to ligand is 1:1 to 1:4; the stirring time is 15 to 60 minutes; the reaction temperature is 90 to 130°C; and the reaction time is 8 to 15 hours.

[0021] More preferably, in step (2), the molar ratio of Ti-MOF to polyvinylpyrrolidone is 1:1; the soaking time is 2 hours; the ligand is 2-aminoterephthalic acid; the molar ratio of the metal salt to the ligand is 1:2; the stirring time is 30 minutes; the reaction temperature is 120°C; and the reaction time is 12 hours.

[0022] The third technical solution of this invention provides an application of a "nuclear-satellite" structure MOF-on-MOF photocatalyst in the photocatalytic reduction of CO2 to CO. Further method: 1 mg of catalyst is dispersed in 0.5 mL of water, and carbon dioxide is introduced at 0.2 MPa. The reaction is carried out under visible light or a xenon lamp irradiation.

[0023] The "core-satellite" structured MOF-on-MOF photocatalyst obtained in this invention effectively retains the structure and morphology of two individual MOFs. The constructed heterojunction structure increases visible light utilization and achieves efficient separation of photogenerated electron-hole pairs. Furthermore, this invention can control the growth amount of UiO-66 nanoparticles by adjusting the ratio of Ti-MOF to the zirconium salt and ligands required for UiO-66 generation, thus realizing the preparation of a nano-confined catalyst.

[0024] Meanwhile, this invention also provides a feasibility for developing photocatalytic CO2 reduction catalysts, achieving efficient photocatalytic CO2 reduction by controlling the exposure surface of the host MOF in MOF-on-MOF.

[0025] The preparation method provided by this invention is simple, easy to implement and mass-produce. Attached Figure Description

[0026] Figure 1 The X-ray powder diffraction pattern of the disc-shaped NH2-MIL-125@NH2-UiO-66 obtained in Example 1 is shown.

[0027] Figure 2 The image shows a scanning electron microscope (SEM) image of the disc-shaped NH2-MIL-125@NH2-UiO-66 obtained in Example 1.

[0028] Figure 3 The image shows the catalytic activity of the disc-shaped NH2-MIL-125, NH2-UiO-66, and disc-shaped NH2-MIL-125@NH2-UiO-66 for carbon dioxide under light conditions obtained in Example 1.

[0029] Figure 4 The X-ray powder diffraction pattern of NH2-MIL-125@NH2-UiO-66 with a rhombic dodecahedral morphology obtained in Example 2 is shown.

[0030] Figure 5The image shows a scanning electron microscope (SEM) image of NH2-MIL-125@NH2-UiO-66 with a rhombic dodecahedral morphology obtained in Example 2.

[0031] Figure 6 The diagram shows the catalytic activity of rhombic dodecahedral NH2-MIL-125, NH2-UiO-66 and rhombic dodecahedral NH2-MIL-125@NH2-UiO-66 for carbon dioxide under light conditions obtained in Example 2.

[0032] Figure 7 The X-ray powder diffraction pattern of NH2-MIL-125@NH2-UiO-66 with a truncated octahedral morphology obtained in Example 3 is shown.

[0033] Figure 8 The image shows a scanning electron microscope (SEM) image of NH2-MIL-125@NH2-UiO-66 with a truncated octahedral morphology obtained in Example 3.

[0034] Figure 9 The diagram shows the catalytic activity of NH2-MIL-125, NH2-UiO-66 and NH2-MIL-125@NH2-UiO-66 with truncated octahedral morphology obtained in Example 3 for carbon dioxide under light conditions. Detailed Implementation

[0035] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention. It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the present invention.

[0036] Furthermore, regarding the numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, are also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0037] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention.

[0038] Example 1

[0039] Preparation of disc-shaped NH2-MIL-125@NH2-UiO-66 composite material:

[0040] (1) Weigh 0.15 mL of tetrabutyl titanate and 140 mg (0.77 mmol) of 2-aminoterephthalic acid and dissolve them in a mixed solution of 9 mL of N,N-dimethylformamide and 1 mL of methanol. Stir for 15 minutes, then transfer to a high-pressure reactor lined with polytetrafluoroethylene and react at 150 °C for 24 hours. The obtained solid product is filtered, washed three times with methanol, and dried under vacuum to obtain NH2-MIL-125 in the form of a disc.

[0041] (2) 100 mg of NH2-MIL-125 in disc form and 100 mg of polyvinylpyrrolidone were dispersed in 100 mL of N,N-dimethylformamide and soaked for 2 hours. 102 mg (0.44 mmol) of zirconium tetrachloride and 145 mg (0.8 mmol) of 2-aminoterephthalic acid were added, and the mixture was stirred for 30 minutes. The mixture was then transferred to a high-pressure reactor lined with polytetrafluoroethylene and reacted at 150 °C for 12 hours. The resulting solid product was filtered, washed, and dried to obtain NH2-MIL-125@NH2-UiO-66 in disc form.

[0042] The X-ray powder diffraction pattern of the disc-shaped NH2-MIL-125@NH2-UiO-66 obtained in Example 1 is shown in Figure 1. Figure 1 .

[0043] The scanning electron microscope image of the disc-shaped NH2-MIL-125@NH2-UiO-66 obtained in Example 1 is shown below. Figure 2 .

[0044] Weigh 1 mg of catalyst and 0.5 mL of water. Use a 300 W xenon lamp as the light source for the photocatalytic experiment. Purge with high-purity (999.99%) carbon dioxide gas, rinse ten times, and use this as the reaction gas. The reaction pressure is 0.2 MPa. Then, irradiate with light (radiant intensity 150 mW / cm²). 2 Samples were taken at 1, 2, 3, 4 and 5 hours respectively, and the results were analyzed by gas chromatography.

[0045] The catalysts used were, respectively, the disc-shaped NH2-MIL-125 obtained in Example 1, the disc-shaped NH2-MIL-125@NH2-UiO-66, and NH2-UiO-66 nanoparticles prepared with zirconium tetrachloride and 2-aminoterephthalic acid solution of the same concentration as in Example 1. The products at different time points were analyzed using an Agilent gas chromatograph. The percentage of CO gas in the total gas content was substituted into PV = nRT (where V represents the total reactor volume of 0.12 m³). 3 The calculated CO production results are shown in the figure. Figure 3 ,from Figure 3As can be seen, CO is the only carbon-containing product, and the disc-shaped NH2-MIL-125@NH2-UiO-66 catalyst yields the highest CO production, with a total yield of 0.162 mmol / g over 5 hours and a CO product selectivity greater than 99%.

[0046] Example 2

[0047] Preparation of NH2-MIL-125@NH2-UiO-66 composite material with a rhombic dodecahedral morphology:

[0048] (1) Weigh 0.34 mL of tetrabutyl titanate and 280 mg (1.54 mmol) of 2-aminoterephthalic acid and dissolve them in a mixed solution of 9 mL of N,N-dimethylformamide, 1 mL of methanol and 0.27 mL of acetic acid. Stir for 15 minutes and transfer to a high-pressure reactor lined with polytetrafluoroethylene. React at 150 °C for 24 hours. The obtained solid product is filtered, washed three times with methanol, and dried under vacuum to obtain NH2-MIL-125 in the form of a rhombic dodecahedron.

[0049] (2) 100 mg of NH2-MIL-125 in the form of a rhombic dodecahedron and 100 mg of polyvinylpyrrolidone were dispersed in 100 mL of N,N-dimethylformamide and soaked for 2 hours. 102 mg (0.44 mmol) of zirconium tetrachloride and 145 mg (0.8 mmol) of 2-aminoterephthalic acid were added, and the mixture was stirred for 30 minutes. The mixture was then transferred to a high-pressure reactor lined with polytetrafluoroethylene and reacted at 150 °C for 12 hours. The resulting solid product was filtered, washed, and dried to obtain NH2-MIL-125@NH2-UiO-66 in the form of a rhombic dodecahedron.

[0050] The X-ray powder diffraction pattern of the rhombic dodecahedral NH2-MIL-125@NH2-UiO-66 obtained in Example 2 is shown below. Figure 4 .

[0051] The scanning electron microscope image of the rhombic dodecahedral NH2-MIL-125@NH2-UiO-66 obtained in Example 2 is shown below. Figure 5 .

[0052] Weigh 1 mg of catalyst and 0.5 mL of water. Use a 300 W xenon lamp as the light source for the photocatalytic experiment. Purge with high-purity (999.99%) carbon dioxide gas, rinse ten times, and use this as the reaction gas. The reaction pressure is 0.2 MPa. Then, irradiate with light (radiant intensity 150 mW / cm²). 2 Samples were taken at 1, 2, 3, 4 and 5 hours respectively, and the results were analyzed by gas chromatography.

[0053] The catalysts used were NH2-MIL-125 with a rhombic dodecahedral morphology obtained in Example 2, NH2-MIL-125@NH2-UiO-66 with a rhombic dodecahedral morphology, and NH2-UiO-66 nanoparticles prepared with zirconium tetrachloride and 2-aminoterephthalic acid solution of the same concentration as in Example 2. The products at different time points were analyzed using an Agilent gas chromatograph. The percentage of CO gas in the total gas content was substituted into PV = nRT (where V represents the total volume of the reactor used, which is 0.12 m³). 3 The calculated CO production results are shown in the figure. Figure 6 ,from Figure 6 As can be seen, CO is the only carbon-containing product. The NH2-MIL-125@NH2-UiO-66 catalyst with a rhombic dodecahedral morphology yielded the highest CO production, with a total yield of 0.258 mmol / g over 5 hours and a CO product selectivity greater than 99%.

[0054] Example 3

[0055] Preparation of NH2-MIL-125@NH2-UiO-66 composite material with truncated octahedral morphology:

[0056] (1) Weigh 0.15 mL of tetrabutyl titanate and 140 mg (0.77 mmol) of 2-aminoterephthalic acid and dissolve them in a mixed solution of 9 mL of N,N-dimethylformamide, 1 mL of methanol and 0.8 mL of acetic acid. Stir for 15 minutes, transfer to a high-pressure reactor lined with polytetrafluoroethylene, and react at 150 °C for 24 hours. The obtained solid product is filtered, washed three times with methanol, and dried under vacuum to obtain NH2-MIL-125 in truncated octahedral form.

[0057] (2) 100 mg of truncated octahedral NH2-MIL-125 and 100 mg of polyvinylpyrrolidone were dispersed in 100 mL of N,N-dimethylformamide and soaked for 2 hours. 102 mg (0.44 mmol) of zirconium tetrachloride and 145 mg (0.8 mmol) of 2-aminoterephthalic acid were added, and the mixture was stirred for 30 minutes. The mixture was then transferred to a polytetrafluoroethylene-lined high-pressure reactor and reacted at 150 °C for 12 hours. The resulting solid product was filtered, washed, and dried to obtain truncated octahedral NH2-MIL-125@NH2-UiO-66.

[0058] The X-ray powder diffraction pattern of NH2-MIL-125@NH2-UiO-66 with a truncated octahedral morphology obtained in Example 3 is shown in [reference needed]. Figure 7 .

[0059] The scanning electron microscope image of NH2-MIL-125@NH2-UiO-66 with a truncated octahedral morphology obtained in Example 3 is shown below. Figure 8 .

[0060] Weigh 1 mg of catalyst and 0.5 mL of water. Use a 300 W xenon lamp as the light source for the photocatalytic experiment. Purge with high-purity (999.99%) carbon dioxide gas, rinse ten times, and use this as the reaction gas. The reaction pressure is 0.2 MPa. Then, irradiate with light (radiant intensity 150 mW / cm²). 2 Samples were taken at 1, 2, 3, 4 and 5 hours respectively, and the results were analyzed by gas chromatography.

[0061] The catalysts used were NH2-MIL-125 with a truncated octahedral morphology obtained in Example 3, NH2-MIL-125@NH2-UiO-66 with a truncated octahedral morphology, and UiO-66 nanoparticles prepared with zirconium tetrachloride and 2-aminoterephthalic acid solution of the same concentration as in Example 3. The products at different time points were analyzed using an Agilent gas chromatograph. The percentage of CO gas in the total gas content was substituted into PV = nRT (where V represents the total reactor volume of 0.12 m³). 3 The calculated CO production results are shown in the figure. Figure 9 ,from Figure 9 As can be seen, CO is the only carbon-containing product, and the NH2-MIL-125@NH2-UiO-66 catalyst with truncated octahedral morphology yields the highest CO production, with a total yield of 0.358 mmol / g over 5 hours and a CO product selectivity greater than 99%.

[0062] As can be seen from the above, the photocatalytic performance of the prepared "nuclear-satellite" structured high-efficiency composite visible light catalyst is greatly improved compared with the two monomer MOFs. The constructed heterostructure achieves efficient separation of photogenerated electrons and photogenerated holes, and the change of the exposed surface of the main MOF also has a significant difference in the effect of improving the catalytic performance. This provides a way of thinking for the development of photocatalytic CO2 reduction catalysts.

[0063] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. The application of a "nuclear-satellite" structured MOF-on-MOF photocatalyst, characterized in that, Application in photocatalytic CO2 reduction to CO production: The catalyst is dispersed in water, carbon dioxide is introduced, and the reaction takes place under visible light or xenon lamp irradiation; The "core-satellite" structure of MOF-on-MOF photocatalyst includes: Ti-MOF with visible light response as the support, i.e. the core, and multiple dispersed UiO-66 nanoparticles grown in situ on the Ti-MOF surface as satellites surrounding the core support; The Ti-MOF is one of MIL-125 with a rhombic dodecahedral or truncated octahedral morphology; Its preparation method includes the following steps: (1) Preparation of Ti-MOF with visible light response; (2) Ti-MOF and polyvinylpyrrolidone were dispersed in N,N-dimethylformamide solution and soaked; metal salt and ligands that form UiO-66 nanoparticles were added, and after the reaction was completed, MOF-on-MOF photocatalyst with "core-satellite" structure was obtained; The preparation steps of Ti-MOF in step (1) include: (b) Preparation of MIL-125 with rhombic dodecahedral morphology: Titanium salt and ligand were dissolved in a mixed solution of N,N-dimethylformamide, methanol and acetic acid. After the reaction was completed, MIL-125 with rhombic dodecahedral morphology was obtained. (c) Preparation of MIL-125 with truncated octahedral morphology: Titanium salt and ligand were dissolved in a mixed solution of N,N-dimethylformamide, methanol and acetic acid. After the reaction was completed, MIL-125 with truncated octahedral morphology was obtained. The titanium salt mentioned in steps (b) and (c) is tetrabutyl titanate, and the ligand is one of unsubstituted terephthalic acid or terephthalic acid substituted with a substituent, wherein the substituent is selected from any one of amino, carboxyl, hydroxyl or halogen. In step (b), the molar ratio of titanium salt to ligand is 10:1 to 1:10; in step (c), the molar ratio of titanium salt to ligand is 5:1 to 1:

5. (b) The volume ratio of N,N-dimethylformamide, methanol, and acetic acid is (8-10):(0.5-2):(0.2-0.4); (c) The volume ratio of N,N-dimethylformamide, methanol and acetic acid is (8-10):(0.5-2):(0.7-0.9); in steps (b) and (c), each 0.1 ml-0.5 ml of tetrabutyl titanate corresponds to a volume of 7-9.5 ml of N,N-dimethylformamide. The reaction occurs at a temperature of 120-180℃ and a reaction time of 12-36 hours in steps (b) and (c).

2. The application according to claim 1, characterized in that, In step (2), the molar ratio of Ti-MOF to polyvinylpyrrolidone is 10:1 to 1:10; the soaking time is 1 to 3 hours; the metal salt is zirconium salt; the ligand is one of unsubstituted terephthalic acid or terephthalic acid with mono- or poly-substituted substituents, wherein the substituent is selected from any one of amino, carboxyl, hydroxyl or halogen; the molar ratio of metal salt to ligand is 1:1 to 1:4; the stirring time is 15 to 60 minutes; the reaction temperature is 90 to 130°C; and the reaction time is 8 to 15 hours.

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