High-efficiency near-infrared responsive photocatalytic composite crystal, preparation method and application thereof

Abstract

The application provides a high-efficiency near-infrared response photocatalytic composite crystal and a preparation method and application thereof, and belongs to the technical field of preparation of non-conventional semiconductor crystals. The application fuses up-conversion nanoparticles NaYF4:Yb,Tm and MOF through a one-step method to obtain up-conversion functionalized MOF nanocomposites, and then prepares multifunctional MOF nanocomposites through an amidation reaction and reversible addition-fragmentation chain transfer polymerization. Finally, the composite nanoparticles are fused with silver phosphate crystals through a biomimetic synthesis strategy to obtain multifunctional ternary composite silver phosphate crystals. The method solves the problems of the limitation of the absorption wavelength range of silver phosphate and photo-corrosion. The photocatalytic composite crystal can effectively degrade rhodamine B under near-infrared light, and has excellent cycle stability while maintaining leading near-infrared photocatalytic activity.

Description

Technical Field

[0001] This invention relates to the field of non-traditional semiconductor crystal preparation technology, and particularly to a high-efficiency near-infrared responsive photocatalytic composite crystal, its preparation method, and its application. Background Technology

[0002] Semiconductors can absorb photons from solar energy with energy equal to or exceeding their band gap, generating electron-hole pairs and driving various photoinduced chemical conversions, making these materials play a crucial role in the conversion of solar energy into chemical energy. However, semiconductor photocatalysts face numerous challenges, such as low separation efficiency and slow migration rate of photogenerated electron-hole pairs, severe photocorrosion, chemical instability, and limited light absorption range, which are key obstacles restricting their practical applications. Overcoming these bottlenecks is crucial for advancing the application of semiconductor photocatalysis in energy conversion and environmental governance.

[0003] In nature, organisms can precisely regulate the formation and structure of biominerals through intricate interactions between biomolecules and mineral crystals. The resulting multi-component hierarchical structures endow biominerals with exceptional mechanical properties and functional adaptability. Inspired by this, scientists are actively exploring biomimetic mineralization strategies to artificially synthesize high-performance composite crystals. However, because rationally controlling the interaction between organic matrices and mineral crystals at the molecular level, and thus overcoming interfacial incompatibilities, remains an unsolved problem, biomimetic mineralization still faces significant challenges. Summary of the Invention

[0004] In view of this, the purpose of this invention is to provide a highly efficient near-infrared responsive photocatalytic composite crystal, its preparation method, and its application.

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

[0006] One of the technical solutions of this invention is a method for preparing a high-efficiency near-infrared responsive photocatalytic composite crystal, comprising the following steps:

[0007] NaYF4:Yb,Tm upconversion nanoparticles were dispersed in solution 1 and reaction 1 was carried out to obtain upconversion functionalized MOF nanocomposite material; the solute in solution 1 was zirconium salt, organic ligand and glacial acetic acid.

[0008] The upconversion functionalized MOF nanocomposite material undergoes an amidation reaction with chain transfer agent CPCP under the action of a coupling agent to obtain CPCP-grafted upconversion functionalized MOF nanocomposite material.

[0009] The upconversion functionalized MOF nanocomposite material grafted with CPCP undergoes a polymerization reaction with polymer monomers under the action of an initiator to obtain a multifunctional MOF nanocomposite material.

[0010] The multifunctional MOF nanocomposite material was dispersed in silver ammonia solution to obtain a mixed solution; then disodium hydrogen phosphate was added to the mixed solution and allowed to stand for reaction to obtain the photocatalytic composite crystal.

[0011] The second technical solution of the present invention is a highly efficient near-infrared responsive photocatalytic composite crystal prepared by the above preparation method.

[0012] The third technical solution of the present invention is the application of the above-mentioned high-efficiency near-infrared responsive photocatalytic composite crystal in the photocatalytic degradation of Rhodamine B.

[0013] The present invention discloses the following technical effects:

[0014] The highly efficient near-infrared responsive photocatalytic composite crystal prepared in this invention is a ternary composite silver phosphate crystal. The specific preparation steps involve modifying the surface of NaYF4:Yb,Tm@MOF with polymer chains to obtain a multifunctional MOF nanocomposite material with excellent colloidal stability. Then, through a biomimetic synthesis-embedding strategy, this material is fused with the host silver phosphate crystal as guest nanoparticles. This method solves the problems of the limited wavelength range of silver phosphate absorption (traditional silver phosphate cannot use near-infrared light) and poor cycle performance.

[0015] This invention utilizes a bio-inspired embedding strategy to prepare ternary composite silver phosphate crystals for the efficient degradation of Rhodamine B under near-infrared light. While maintaining leading near-infrared photocatalytic activity, it exhibits excellent cycling stability. This provides an effective strategy for the rational design of next-generation photocatalysts to overcome current limitations. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 Transmission electron microscope image of NaYF4:Yb,Tm upconversion nanoparticles obtained in Example 1;

[0018] Figure 2 The image shows a transmission microscope image of the upconversion functionalized UiO-66-NH2 nanocomposite material obtained in Example 2.

[0019] Figure 3 The image shows a transmission microscope image of the multifunctional UiO-66-NH2 nanocomposite material obtained in Example 3.

[0020] Figure 4Scanning electron microscope images of the ternary composite silver phosphate crystals obtained in Example 4 at different magnifications, where a is 20 μm and b is 1 μm;

[0021] Figure 5 FTIR images of different materials in Examples 1-4;

[0022] Figure 6 The graph shows the change in the degree of degradation of Rhodamine B by different catalysts over time under near-infrared light in the performance test.

[0023] Figure 7 For performance testing, a bar chart showing the degradation degree constant of the ternary composite silver phosphate crystal (NaYF4:Yb,Tm@UiO-66-PMAA@Ag3PO4) obtained in Example 4 during ten catalytic cycles driven by near-infrared radiation is presented. Detailed Implementation

[0024] 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.

[0025] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to 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, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0026] 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. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0027] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0028] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0029] In this invention, unless otherwise specified, room temperature means 25±5 ℃.

[0030] This invention first obtains upconversion nanoparticles with uniform particle size distribution and good colloidal stability through solvothermal synthesis; then, it fuses the upconversion nanoparticles NaYF4:Yb,Tm with MOF (UiO-66-NH2) in a one-step process to obtain upconversion functionalized MOF (UiO-66-NH2) nanocomposite material; subsequently, it prepares multifunctional MOF (UiO-66-NH2) nanocomposite material through amidation reaction and reversible addition-fragmentation chain transfer polymerization; finally, it fuses the composite nanoparticles with silver phosphate crystals through a biomimetic synthesis strategy to obtain multifunctional ternary composite silver phosphate crystals.

[0031] The first aspect of this invention provides a method for preparing a highly efficient near-infrared responsive photocatalytic composite crystal, comprising the following steps:

[0032] NaYF4:Yb,Tm upconversion nanoparticles were dispersed in solution 1 and reaction 1 was carried out to obtain upconversion functionalized MOF nanocomposite material; the solute in solution 1 was zirconium salt, organic ligand and regulator.

[0033] The upconversion functionalized MOF nanocomposite material undergoes an amidation reaction with chain transfer agent CPCP under the action of a coupling agent to obtain CPCP-grafted upconversion functionalized MOF nanocomposite material.

[0034] The upconversion functionalized MOF nanocomposite material grafted with CPCP undergoes a polymerization reaction with polymeric monomers under the action of an initiator to obtain a multifunctional MOF nanocomposite material (the particle size of the multifunctional MOF nanocomposite material is about 100-400 nm).

[0035] The multifunctional MOF nanocomposite material was dispersed in silver ammonia solution to obtain a mixed solution; then disodium hydrogen phosphate was added to the mixed solution and allowed to stand for reaction to obtain the photocatalytic composite crystal.

[0036] In a preferred embodiment of the present invention, the preparation method of the NaYF4:Yb,Tm upconversion nanoparticles is as follows: rare earth salt, ammonium fluoride, sodium chloride, and a capping agent are added to a solvent for reaction 2. The particle size of the NaYF4:Yb,Tm upconversion nanoparticles prepared by the present invention is approximately 9-30 nm.

[0037] More preferably, the rare earth salt comprises 77%-98% Y. 3+ 1-21% of Yb3+ and margin Tm 3+ The capping agent is a branched polymer; the solvent is ethylene glycol; the molar ratio of the rare earth salt, ammonium fluoride, sodium chloride, and capping agent is (0.1-0.8):(0.3-5):(0.1-2):(0.001-0.01) (more preferably, (0.1-0.3):(0.3-1):(0.1-0.5):(0.001-0.01)); the temperature of reaction 2 is 150-200 °C, and the time is 1-3 h. This invention does not impose a special limitation on the amount of ethylene glycol used, as long as the amount is sufficient for reaction 2 to proceed.

[0038] More preferably, the branched polymer is branched polyethyleneimine (BPEI).

[0039] In a preferred embodiment of the present invention, the zirconium salt is zirconium tetrachloride; the organic ligand is 2-aminoterephthalic acid; the regulator is glacial acetic acid; the mass ratio of zirconium tetrachloride, 2-aminoterephthalic acid and glacial acetic acid is (50-150):(70-200):(6-30); after dispersing NaYF4:Yb,Tm upconversion nanoparticles in solution 1, the content of NaYF4:Yb,Tm upconversion nanoparticles in the resulting mixed solution is 5-60 mg;

[0040] The temperature of reaction 1 is 100-150 °C, and the time is 1.5-3.5 h.

[0041] In a preferred embodiment of the present invention, the solvent in solution 1 is N,N-dimethylformamide (DMF). The present invention does not impose any special limitation on the amount of DMF used, as long as the amount is sufficient to allow reaction 1 to proceed.

[0042] In a preferred embodiment of the present invention, the coupling agent is 4-(4,6-dimethoxytriazine-2-yl)-4-methylmorpholine hydrochloride (DMTMM); the mass ratio of the coupling agent to the chain transfer agent CPCP (4-cyano-4-(phenylcarbonylthio)pentanoic acid) is (2-6):1; the mass ratio of the chain transfer agent CPCP to the upconversion functionalized MOF nanocomposite material is (2.5-6.5):1; the amidation reaction is carried out at room temperature for 6-24 h.

[0043] In a preferred embodiment of the present invention, the polymerizing monomer is a methacrylic acid compound; the initiator is an azo initiator; and the ratio of the upconversion functionalized MOF nanocomposite material, the polymerizing monomer, and the initiator is 50-70 mg: 24-27 mmol: 0.04-0.06 mmol.

[0044] The polymerization reaction is carried out at a temperature of 50-70 °C for 6-24 h.

[0045] More preferably, the methacrylic acid compound is methacrylic acid (MAA); and the azo initiator is ACVA (4,4'-azobis(4-cyanopentanoic acid)).

[0046] In a preferred embodiment of the present invention, the content of the multifunctional MOF nanocomposite material in the mixed solution is 0.2-2.4 g / L (more preferably, 0.2-1 g / L), the ammonia content is 5-30 g / L (more preferably, 20-30 g / L), and the silver ion concentration is 5-20 g / L (more preferably, 8-15 g / L); the mass ratio of the multifunctional MOF nanocomposite material to disodium hydrogen phosphate is 1:(20-23).

[0047] In a preferred embodiment of the present invention, the temperature of the static reaction is 20-30 °C and the time is 8-48 h (more preferably, 24-48 h).

[0048] The second aspect of the present invention provides a highly efficient near-infrared responsive photocatalytic composite crystal (ternary composite silver phosphate crystal) prepared by the above preparation method.

[0049] The ternary composite silver phosphate crystals provided by this invention have a particle size of approximately 100-400 μm.

[0050] The ternary composite silver phosphate crystal provided by this invention first uses a multifunctional MOF (UiO-66-NH2) nanocomposite material as guest particles, and then biomimetically synthesizes and embeds it with silver phosphate single crystals to obtain a multifunctional ternary composite silver phosphate material. During the growth of silver phosphate crystals, the multifunctional MOF (UiO-66-NH2) nanocomposite material is anchored to its crystal face and gradually fused with the crystal to form a ternary composite silver phosphate crystal.

[0051] A third aspect of the present invention provides an application of the above-mentioned high-efficiency near-infrared responsive photocatalytic composite crystal in the photocatalytic degradation of Rhodamine B.

[0052] In a preferred embodiment of the present invention, during the photocatalytic degradation of Rhodamine B, the concentration of Rhodamine B in the wastewater containing Rhodamine B is 10 mg / L, and the amount of high-efficiency near-infrared responsive photocatalytic composite crystal is 0.5-1 mg / mL; the irradiation wavelength during photocatalysis is 980 nm, and the intensity is 0.475 W.

[0053] Unless otherwise specified, the technical solutions described in this invention are all conventional solutions in the field, and the reagents or raw materials used are all purchased from commercial channels or are publicly available unless otherwise specified.

[0054] To better understand the present invention, the following embodiments further illustrate the content of the present invention, but the content of the present invention is not limited to the following embodiments.

[0055] Example 1

[0056] The preparation process of NaYF4:Yb,Tm upconversion nanoparticles is as follows:

[0057] Sodium chloride (NaCl, 84 mg, 1.438 mmol), yttrium trichloride hexahydrate (YCl3·6H2O, 153 mg, 0.501 mmol), ytterbium trichloride hexahydrate (YbCl3·6H2O, 50 mg, 0.130 mmol), thulium trichloride hexahydrate (TmCl3·6H2O, 5 mg, 0.013 mmol), and branched polyethyleneimine (BPEI, 0.3 g, 0.006 mmol) were dissolved in 6 mL of ethylene glycol (EG). Then, 6 mL of EG solution containing ammonium fluoride (NH4F, 150 mg, 4.05 mmol) was added to this solution. After stirring for 10 minutes, the mixture was transferred to a 50 mL polyacrylonitrile-lined high-pressure reactor and reacted at 200 °C for 3 hours. The obtained nanoparticles were collected by centrifugation at 10,000 rpm, thoroughly washed with ethanol and deionized water, and finally redispersed in 10 mL of N,N-dimethylformamide (DMF) to obtain a NaYF4:Yb,Tm dispersion with a concentration of approximately 10 mg / mL. Figure 1 The image is a transmission electron microscope image of NaYF4:Yb,Tm, with the inset being a digital photograph of its upconversion luminescence under 980 nm near-infrared light excitation.

[0058] Example 2

[0059] The preparation process of upconversion functionalized UiO-66-NH2 nanocomposite material (NaYF4: Yb, Tm / UiO-66-NH2 nanocomposite material) is as follows:

[0060] Zirconium tetrachloride (ZrCl4, 122 mg, 0.526 mmol) and 2-aminoterephthalic acid (BDC-NH2, 174 mg, 0.959 mmol) were dissolved in 120 mL of DMF in a 250 mL round-bottom flask, followed by the addition of 10 mL of acetic acid. The resulting solution was sonicated for 15 minutes, and then 5 mL of DMF solution containing NaYF4:Yb,Tm nanoparticles (60 mg) was added. The mixture was sonicated for another 5 minutes and sealed, then transferred to an oil bath preheated to 150 °C and allowed to stand for 3 hours. The nanocomposite material was collected by centrifugation at 9500 rpm, washed three times with DMF and twice with methanol, and finally dispersed in 10 mL of methanol for later use (5 mg / mL). Figure 2 (Transmission microscope image of upconversion functionalized UiO-66-NH2 nanocomposite particles).

[0061] In contrast, the preparation of non-upconversion functionalized UiO-66-NH2 nanoparticles is the same as that of upconversion functionalized UiO-66-NH2 nanocomposites, the only difference being that the addition of NaYF4:Yb,Tm nanoparticles is omitted.

[0062] Example 3

[0063] The preparation process of the multifunctional UiO-66-NH2 nanocomposite material (NaYF4: Yb, Tm / UiO-66-PMAA nanocomposite material) is as follows:

[0064] The NaYF4:Yb,Tm / UiO-66-NH2 nanocomposite material (60 mg) was dispersed in 30 mL of methanol in a round-bottom flask. CPCP (186 mg, 0.668 mmol) and DMTMM (746 mg, 2.698 mmol) were added under continuous stirring. After 12 hours of reaction, the CPCP-grafted upconversion functionalized UiO-66-NH2 nanocomposite material was collected by centrifugation and washed four times with methanol. The grafted nanocomposite material was redispersed in 10 mL of methanol, and methacrylic acid (MAA, 2.29 g, 26.648 mmol) and ACVA (16 mg, 0.053 mmol) were added sequentially. The reaction system was sealed and placed in an ice-water bath, bubbled with nitrogen for 20 minutes, then transferred to an oil bath preheated to 70°C and stirred for 24 hours to initiate polymerization. After the reaction was completed, the multifunctional UiO-66-NH2 nanocomposite material was collected by centrifugation, washed three times with methanol and four times with deionized water, and finally redispersed in 10 mL of deionized water for later use. Figure 3 (Transmission microscope image of multifunctional UiO-66-NH2 nanoparticles).

[0065] As a control, the preparation of UiO-66-PMAA nanoparticles was the same as that of the multifunctional UiO-66-NH2 nanocomposite material, except that the NaYF4:Yb,Tm / UiO-66-NH2 nanocomposite material was replaced with the non-upconversion functionalized UiO-66-NH2 nanoparticles in Example 2.

[0066] Example 4

[0067] The preparation process of ternary composite silver phosphate crystal (NaYF4:Yb,Tm / UiO-66-PMAA@Ag3PO4 composite crystal) is as follows:

[0068] First, silver nitrate (AgNO3, 240 mg, 1.41 mmol) was dissolved in 0.30 mL of deionized water, and then 10 mL of ammonia solution (containing 408 mg of ammonia) was added. After stirring for 10 minutes, 5 mL of deionized water containing NaYF4:Yb,Tm / UiO-66-PMAA nanocomposite material (8 mg) was added, and stirring continued for 15 minutes. Subsequently, 3 mL of deionized water containing disodium hydrogen phosphate (Na2HPO4, 170 mg, 1.198 mmol) was added, and stirring was continued for 3 minutes. After standing for 24 hours, the precipitate was the obtained NaYF4:Yb,Tm / UiO-66-PMAA@Ag3PO4 composite crystal. Figure 4 (Scanning electron microscope image of a ternary composite silver phosphate crystal).

[0069] As a control, the preparation of blank Ag3PO4 crystals was the same as that of NaYF4:Yb,Tm / UiO-66-PMAA@Ag3PO4 composite crystals, the only difference being that NaYF4:Yb,Tm / UiO-66-PMAA nanocomposite materials were not added.

[0070] Material characterization:

[0071] Characterization of different materials using Fourier-exchange infrared spectroscopy (FTIR) Figure 5 By comparing the infrared characteristic peaks of different materials, the successful preparation of multifunctional UiO-66-NH2 nanocomposite materials and NaYF4:Yb,Tm / UiO-66-PMAA@Ag3PO4 composite crystals can be demonstrated.

[0072] Performance testing:

[0073] Photodegradation of Rhodamine B (RhB) under Near-Infrared Irradiation: The photocatalytic degradation of the model dye Rhodamine B (RhB) was investigated under 980 nm near-infrared light (0.475 W). A typical procedure was as follows: 10 mg of photocatalyst was dispersed in 15 mL of RhB aqueous solution (10 mg / L), and the mixture was magnetically stirred in the dark for 90 minutes to establish adsorption-desorption equilibrium before irradiation. During the photocatalytic reaction, 1 mL samples were collected at predetermined time intervals (10 min, 20 min, 30 min, 40 min). The photocatalyst was separated by centrifugation (10,000 rpm, 5 min), and the residual RhB concentration in the supernatant was analyzed. Figure 6 It can be seen that NaYF4:Yb,Tm / UiO-66-PMAA and Ag3PO4 cannot complete near-infrared photoresponsive catalysis on their own (the degradation curves of the two materials show almost no change within forty minutes), while NaYF4:Yb,Tm / UiO-66-PMAA@Ag3PO4 can effectively degrade Rhodamine B under near-infrared light excitation (degradation is completed in 40 minutes).

[0074] Circular research

[0075] The photocatalyst recovered by centrifugation (NaYF4:Yb,Tm / UiO-66-PMAA@Ag3PO4 composite crystal from Example 4) was washed twice with deionized water and dried before being used in subsequent recycling experiments. Figure 7 It can be seen that the photocatalyst still maintains high catalytic performance after 10 cycles.

[0076] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a highly efficient near-infrared responsive photocatalytic composite crystal, characterized in that, Includes the following steps: NaYF4:Yb,Tm upconversion nanoparticles were dispersed in solution 1, and reaction 1 was carried out to obtain upconversion functionalized MOF nanocomposite material; the solute in solution 1 was zirconium salt, organic ligand and regulator; the organic ligand was 2-aminoterephthalic acid; The upconversion functionalized MOF nanocomposite material undergoes an amidation reaction with chain transfer agent CPCP under the action of a coupling agent to obtain CPCP-grafted upconversion functionalized MOF nanocomposite material. The upconversion functionalized MOF nanocomposite material grafted with CPCP undergoes a polymerization reaction with polymer monomers under the action of an initiator to obtain a multifunctional MOF nanocomposite material. The polymerization monomer is a methacrylic acid compound; The multifunctional MOF nanocomposite material was dispersed in silver ammonia solution to obtain a mixed solution; then disodium hydrogen phosphate was added to the mixed solution and allowed to stand for reaction to obtain the photocatalytic composite crystal.

2. The preparation method according to claim 1, characterized in that, The preparation method of the NaYF4:Yb,Tm upconversion nanoparticles is as follows: rare earth salt, ammonium fluoride, sodium chloride and end-capping agent are added to a solvent and reacted 2.

3. The preparation method according to claim 2, characterized in that, The rare earth salt comprises 77%-98% Y by molar percentage. 3+ 1-21% of Yb 3+ and margin Tm 3+ The capping agent is a branched polymer; the solvent is ethylene glycol; the molar ratio of the rare earth salt, ammonium fluoride, sodium chloride and capping agent is (0.1-0.8):(0.3-5):(0.1-2):(0.001-0.01); the temperature of reaction 2 is 150-200 ℃ and the time is 1-3 h.

4. The preparation method according to claim 1, characterized in that, The zirconium salt is zirconium tetrachloride; the regulator is glacial acetic acid; the mass ratio of zirconium tetrachloride, 2-aminoterephthalic acid and glacial acetic acid is (50-150):(70-200):(6-30); after dispersing NaYF4:Yb,Tm upconversion nanoparticles in solution 1, the content of NaYF4:Yb,Tm upconversion nanoparticles in the resulting mixed solution is 5-60 mg; The temperature of reaction 1 is 100-150 °C, and the time is 1.5-3.5 h.

5. The preparation method according to claim 1, characterized in that, The coupling agent is 4-(4,6-dimethoxytriazine-2-yl)-4-methylmorpholine hydrochloride; the mass ratio of the coupling agent to the chain transfer agent CPCP is (2-6):1; the mass ratio of the chain transfer agent CPCP to the upconversion functionalized MOF nanocomposite material is (2.5-6.5):1; the amidation reaction is carried out at room temperature for 6-24 h.

6. The preparation method according to claim 1, characterized in that, The initiator is an azo initiator; the ratio of the upconversion functionalized MOF nanocomposite material, the polymer monomer, and the initiator is 50-70 mg: 24-27 mmol: 0.04-0.06 mmol; The polymerization reaction is carried out at a temperature of 50-70 °C for 6-24 h.

7. The preparation method according to claim 1, characterized in that, The mixed solution contains 0.2-2.4 g / L of multifunctional MOF nanocomposite material, 5-30 g / L of ammonia, and 5-20 g / L of silver ions; the mass ratio of the multifunctional MOF nanocomposite material to disodium hydrogen phosphate is 1:(20-23).

8. The preparation method according to claim 1, characterized in that, The static reaction is carried out at a temperature of 20-30 °C for 8-48 h.

9. A highly efficient near-infrared responsive photocatalytic composite crystal prepared by the preparation method according to any one of claims 1-8.

10. The application of the high-efficiency near-infrared responsive photocatalytic composite crystal of claim 9 in the photocatalytic degradation of Rhodamine B.

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