Metal-polymer hybrid nanoparticles and uses thereof

Abstract

The invention relates to a metal-polymer hybrid nano particle, the metal-polymer hybrid nano particle comprises a block polymer containing a polymerization chain segment a and a polymerization chain segment b and metal, the polymerization chain segment a contains a repetitive unit obtained by polymerization of a nitrogen-containing monomer, and the polymerization chain segment b contains a repetitive unit obtained by polymerization of a nucleating monomer. The metal-polymer hybrid nano particle is suitable for being used as a chemical reaction catalyst, and especially has good catalytic efficiency and catalytic cycle performance on a catalytic reduction reaction of 4-nitrophenol.

Description

Technical Field

[0001] The present invention belongs to the field of polymer materials, and particularly relates to a metal-polymer hybrid nanoparticle and its application. Technical Background

[0002] Metal nanomaterials, such as gold, silver, palladium, iron, ruthenium, etc., have extensive applications in the fields of chemical synthesis, environmental protection, energy conversion, etc. At present, metal / polymer hybrid nanoparticles have been widely studied due to the wide sources of polymers, easy preparation, variable functions, strong adaptability, etc.

[0003] However, in the field of chemical reaction catalysts, in order to obtain a catalyst with high efficiency and long service life, it is necessary to consider the loading amount of metal particles in the hybrid nanoparticles, the interaction between the particles and the polymer, and the structure of the nanoparticles. These factors may all affect the performance of the final catalyst. Therefore, it is of great significance to develop a metal-polymer hybrid nanomaterial with uniform structure, high loading amount, and excellent catalytic efficiency. Summary of the Invention

[0004] In view of this, the present invention provides the following technical solutions. By selecting appropriate monomer types and relying on living radical polymerization combined with polymerization-induced self-assembly technology, hybrid nanoparticles with high metal loading are obtained simply and efficiently. The particle size of the nanoparticles can be adjusted and the particle size distribution is uniform, and it has good catalytic efficiency and catalytic cycle stability.

[0005] In the first aspect, the present invention provides a metal-polymer hybrid nanoparticle, which includes a block polymer containing the following polymerization segments a and b and a metal:

[0006] (A) A polymerization segment a polymerized from at least one nitrogen-containing monomer, and the structural formula of the nitrogen-containing monomer

[0007] is as shown in formula (I):

[0008] and,

[0009] (B) A polymerization segment b polymerized from at least one nucleating monomer, and the structural formula of the nucleating monomer

[0010] is as shown in formula (II):

[0011]

[0012] Wherein:

[0013] The R of each nitrogen-containing monomer 1 can be the same or different and are each independently selected from H or methyl.

[0014] The R of each nitrogen-containing monomer 2 may be the same or different and are each independently selected from R 4 substituted C 1-10 alkyl groups, and the R 4 is selected from at least one of amino, di(C 1-5 alkyl)amino, pyridyl, pyrrolyl, imidazolyl, pyrazolyl, oxazolyl, pyrimidinyl, indolyl, pyrazinyl, quinolinyl or isoquinolinyl.

[0015] Preferably, the R 4 is selected from at least one of amino, dimethylamino, diethylaminopyridyl, pyrrolyl, imidazolyl, pyrazolyl or pyrimidinyl.

[0016] Preferably, the R 2 is selected from at least one of the following groups:

[0017]

[0018] The R of each nucleating monomer 3 may be the same or different and are each independently selected from C 1-10 alkyl groups, C 1-25 oxoalkyl groups containing 1-20 oxygen atoms, C 1-10 alkyl groups substituted with 1-5 hydroxyl groups, or C 5 alkyl groups substituted with R 1-10 where the R 5 is selected from at least one of acetylacetonate group, phenyl, naphthyl, phenoxy, naphthoxy, tetrahydrofuranyl, p-benzenecarbaldehyde or p-ethoxybenzaldehyde.

[0019] Preferably, the R 3 may be the same or different and are each independently selected from C 2-6 alkyl groups, C 1-20 oxoalkyl groups containing 1-10 oxygen atoms, C 2-6 alkyl groups substituted with hydroxyl groups, or C 5 alkyl groups substituted with R 1-6 where the R 5 is selected from at least one of acetylacetonate group, phenyl, naphthyl, phenoxy, naphthoxy, tetrahydrofuranyl or p-ethoxybenzaldehyde.

[0020] Preferably, the R 3 is selected from at least one of the following groups:

[0021]

[0022]

[0023] Preferably, in some specific embodiments, the nitrogen-containing monomer is

[0024]

[0025] The nitrogen element in the nitrogen-containing monomer of the present invention can serve as a site for complexing metal particles. Preferably, the polymer segment a obtained by polymerizing such monomers is hydrophilic. The inventors found that (meth)acrylate monomers containing nitrogen atoms are suitable as nitrogen-containing monomers for hybrid nanoparticles. The nitrogen atom of the nitrogen-containing monomer can be derived from an amino group or a nitrogen-containing heterocycle. As a specific example, dimethylaminoethyl methacrylate is particularly preferred.

[0026] Preferably, in some specific embodiments, the nucleating monomer is

[0027]

[0028] The nucleating monomer of the present invention preferably has a certain steric hindrance, which can usually be obtained through an alkyl chain, an alkoxy chain, a hydroxyl group, and a cyclic compound group (such as an aromatic group or a heterocyclic group) or a combination thereof. Preferably, the polymer segment b obtained by polymerizing such monomers is hydrophobic, which is convenient for forming nanoparticles in the polymerization-induced self-assembly process (PISA).

[0029] Preferably, the content of the polymerization repeating unit derived from the nitrogen-containing monomer in the block polymer is 5-90 mol%.

[0030] Preferably, the content of the polymerization repeating unit derived from the nitrogen-containing monomer in the block polymer is 20-80 mol%.

[0031] Preferably, the content of the polymerization repeating unit derived from the nitrogen-containing monomer in the block polymer is 25-70 mol%.

[0032] In some specific embodiments, the content of the polymerization repeating unit derived from the nitrogen-containing monomer in the block polymer can be 10 mol%, 15 mol%, 20 mol%, 25 mol%, 30 mol%, 35 mol%, 40 mol%, 45 mol%, 50 mol%, 55 mol%, 60 mol%, 65 mol%, 70 mol%, 75 mol%, 80 mol%, 85 mol% or 90 mol%.

[0033] Preferably, the content of the polymerization repeating unit derived from the nucleating monomer in the block polymer is 10-95 mol%.

[0034] Preferably, the content of the polymerization repeating unit derived from the nucleating monomer in the block polymer is 20-80 mol%.

[0035] Preferably, the content of the polymerization repeating units derived from the nucleating monomer in the block polymer is 30 - 75 mol%.

[0036] In some specific embodiments, the content of the polymerization repeating units derived from the nucleating monomer in the block polymer can be 10 mol%, 15 mol%, 20 mol%, 25 mol%, 30 mol%, 35 mol%, 40 mol%, 45 mol%, 50 mol%, 55 mol%, 60 mol%, 65 mol%, 70 mol%, 75 mol%, 80 mol%, 85 mol% or 90 mol%.

[0037] The content of the nitrogen-containing monomer in the block polymer can adjust the loading amount and loading form of the metal particles, and the content of the nucleating monomer can control the morphology and particle size of the hybrid nanoparticles, etc., to obtain hybrid nanoparticles with different dispersion and loading conditions of the metal particles.

[0038] Preferably, the metal is selected from at least one of gold, silver, palladium, iron or ruthenium.

[0039] Preferably, the metal is selected from gold or silver.

[0040] In some preferred specific embodiments, the metal is silver.

[0041] Preferably, the content of the metal in the metal-polymer hybrid nanoparticles is 0.01 - 10 wt%.

[0042] Preferably, the content of the metal in the metal-polymer hybrid nanoparticles is 0.1 - 8 wt% or 0.5 - 5 wt%.

[0043] Preferably, in some specific embodiments, the content of the metal in the metal-polymer hybrid nanoparticles of the present invention is 0.1 wt%, 0.2 wt%, 0.5 wt%, 1 wt%, 1.5 wt%, 2 wt%, 2.5 wt%, 3 wt%, 3.5 wt%, 4 wt%, 4.5 wt% or 5 wt%.

[0044] Preferably, the particle size of the metal-polymer hybrid nanoparticles is 10 - 99 nm.

[0045] Preferably, the particle size of the metal-polymer hybrid nanoparticles is 15 - 92 nm.

[0046] Preferably, the particle size of the metal-polymer hybrid nanoparticles is 20 - 88 nm.

[0047] In some specific embodiments, the particle size of the metal-polymer hybrid nanoparticles of the present invention can be 10 nm, 15 nm, 20 nm, 25 nm, 30 nm, 35 nm, 40 nm, 45 nm, 50 nm, 55 nm, 60 nm, 65 nm, 70 nm, 75 nm, 80 nm, 85 nm, 90 nm, 95 nm or 98 nm.

[0048] In some preferred specific embodiments, the particle size of the metal-polymer hybrid nanoparticles of the present invention can be 20 - 30 nm or 75 - 88 nm.

[0049] The inventors found that the particle size of the metal-polymer hybrid nanoparticles has a certain influence on the catalytic performance of the material. Through the monomer selection and preparation method of the present invention, metal hybrid nanomaterials with a smaller particle size (less than 100 nm) can be prepared, the specific surface area of the catalyst can be increased, and they are not easily agglomerated during use. At the same time, the catalytic efficiency of the catalyst and the catalyst cycle stability are improved.

[0050] In a second aspect, the present invention provides a method for preparing the metal-polymer hybrid nanoparticles of any one of the foregoing, comprising the following steps:

[0051] (S1) Polymerize a nitrogen-containing monomer by a living radical polymerization method to obtain a macroinitiator containing a polymer chain segment a;

[0052] (S2) Use a polymerization-induced self-assembly method to polymerize the macroinitiator and a nucleating monomer in step S1 to obtain block copolymer nanoparticles containing a polymer chain segment a and a polymer chain segment b;

[0053] (S3) React the block copolymer nanoparticles obtained in step S2 with a metal compound to obtain metal-polymer hybrid nanoparticles.

[0054] Preferably, in the method, the living radical polymerization method in step S1 is reversible addition-fragmentation chain transfer (RAFT) polymerization.

[0055] Preferably, in the method, step S1 includes: polymerizing the nitrogen-containing monomer of the present invention to obtain a macroinitiator under the action of a RAFT chain transfer agent and an initiator.

[0056] Generally, according to the need for the degree of polymerization of the nitrogen-containing monomer in the polymer chain segment a, the molar ratios of the monomer, the RAFT chain transfer agent and the initiator during the reaction, as well as the reaction temperature and time, can be adjusted according to conventional technical means in the art.

[0057] Preferably, in the method, the molar ratio of the macroinitiator to the nucleating monomer in step S2 is 1:20 - 1:150 or 1:30 - 1:120, and can be, for example, 1:40, 1:50, 1:60, 1:70, 1:80, 1:90, 1:100, or 1:110, etc.

[0058] The inventors found that the particle size of the polymer nanoparticles can be regulated by controlling the ratio of the nucleating monomer to the macroinitiator, and then the particle size of the final metal-polymer hybrid nanoparticles can be regulated.

[0059] Generally, after the polymer nanoparticles are loaded with metal, since the metal content is relatively small compared to the polymer content, the particle size basically does not change significantly. In the embodiments of the present invention, the particle size of the polymer nanoparticles is used to characterize the particle size of the final metal-polymer hybrid nanoparticles.

[0060] Preferably, in step S3, the mass ratio of the block copolymer nanoparticles to the metal compound is 1:0.001 - 1:1, 1:0.002 - 1:0.5, 1:0.005 - 1:0.1, or 1:0.01 - 1:0.05.

[0061] Preferably, in some specific embodiments, the mass ratio of the block copolymer nanoparticles to the metal compound in step S3 is 1:0.001, 1:0.002, 1:0.005, 1:0.01, 1:0.015, 1:0.02, 1:0.025, 1:0.03, 1:0.05, 1:0.1, 1:0.2, 1:0.5, or 1:0.8.

[0062] Preferably, the metal compound is a metal salt. For example, the metal compound can be silver nitrate, chloroauric acid, sodium chloropalladate, etc.

[0063] Preferably, the RAFT chain transfer agent can be a common dithioester or trithioester, and specifically, for example, it can be dithiobenzoic acid 4-cyanopentanoate or protonated 2-cyanopropyl N-methyl-N-(4-pyridyl)aminodithiocarbonate, etc.

[0064] Preferably, the initiator includes azo initiators, peroxide initiators, or photoinitiators, etc. For example, the initiator can be azobisisobutyronitrile (AIBN), azobisisoheptonitrile (ABVN), hydrogen peroxide, benzoyl peroxide (BPO), diethylhexyl peroxydicarbonate (EHP), potassium persulfate, ammonium persulfate, Eosin Y, methyl vinyl ketone, benzoin, benzophenone, and fluorescein, etc.

[0065] Preferably, the molar ratio of the RAFT chain transfer agent to the initiator in step S1 is 20:1 - 5:1, and preferably 10:1.

[0066] Preferably, the initiators in the step S1 and the step S2 may be the same or different.

[0067] Preferably, the polymerization reaction solvent in the step S1 and the step S2 is at least one of tetrahydrofuran, diethyl ether, toluene, water, methanol or ethanol.

[0068] Preferably, the polymerization temperature in the step S1 and the step S2 may be 0 - 100 °C, and the polymerization time is 2 - 30 h.

[0069] Preferably, the reaction in the step S3 is carried out in the presence of a reducing agent. The reducing agent may be sodium borohydride or lithium aluminum hydride, etc.

[0070] In a third aspect, the present invention provides the use of the metal - polymer hybrid nanoparticles prepared by the method of any one of the foregoing as a chemical reaction catalyst.

[0071] Preferably, the chemical reaction is selected from at least one of oxidation reaction, reduction reaction, hydrogenation reaction, hydrogen evolution reaction or electrochemical reaction.

[0072] In a specific embodiment, the metal - polymer hybrid nanoparticles of the present invention are particularly suitable as a catalyst for the catalytic reduction reaction of 4 - nitrophenol.

[0073] Preferably, in the catalytic reduction reaction of 4 - nitrophenol, the dosage of the catalyst is 0.1 - 20 wt% of the mass of 4 - nitrophenol, preferably 1 - 5 wt%, and for example, it may be 0.2 wt%, 0.5 wt%, 1 wt%, 1.5 wt%, 2 wt%, 2.5 wt%, 3 wt%, 3.5 wt%, 4 wt%, 4.5 wt%, 5 wt%, 10 wt%, 15 wt% or 20 wt%. BRIEF DESCRIPTION OF THE DRAWINGS

[0074] Figure 1 : Characterization of nanoparticles with a size of about 20 nm (a) TEM image, (b) DLS graph, (c) alcohol - phase emulsion photograph.

[0075] Figure 2 : Characterization of nanoparticles with a size of about 30 nm (a) TEM image, (b) DLS graph, (c) alcohol - phase emulsion photograph.

[0076] Figure 3 : Characterization of nanoparticles with a size of about 40 nm (a) TEM image, (b) DLS graph, (c) alcohol - phase emulsion photograph.

[0077] Figure 4: Characterization of nanoparticles with a size of about 50 nm (a) TEM image, (b) DLS graph, (c) alcohol-phase emulsion photo.

[0078] Figure 5 : Characterization of nanoparticles with a size of about 60 nm (a) TEM image, (b) DLS graph, (c) alcohol-phase emulsion photo.

[0079] Figure 6 : Characterization of nanoparticles with a size of about 70 nm (a) TEM image, (b) DLS graph, (c) alcohol-phase emulsion photo.

[0080] Figure 7 : Characterization of nanoparticles with a size of about 80 nm (a) TEM image, (b) DLS graph, (c) alcohol-phase emulsion photo.

[0081] Figure 8 : Characterization of silver hybrid nanoparticles with a size of about 20 nm (a) TEM image, (b) UV absorption spectrum, (c) alcohol-phase emulsion photo.

[0082] Figure 9 : Characterization of silver hybrid nanoparticles with a size of about 30 nm (a) TEM image, (b) UV absorption spectrum, (c) alcohol-phase emulsion photo.

[0083] Figure 10 : Characterization of silver hybrid nanoparticles with a size of about 40 nm (a) TEM image, (b) UV absorption spectrum, (c) alcohol-phase emulsion photo.

[0084] Figure 11 : Characterization of silver hybrid nanoparticles with a size of about 50 nm (a) TEM image, (b) UV absorption spectrum, (c) alcohol-phase emulsion photo.

[0085] Figure 12 : Characterization of silver hybrid nanoparticles with a size of about 60 nm (a) TEM image, (b) UV absorption spectrum, (c) alcohol-phase emulsion photo.

[0086] Figure 13 : Characterization of silver hybrid nanoparticles with a size of about 70 nm (a) TEM image, (b) UV absorption spectrum, (c) alcohol-phase emulsion photo.

[0087] Figure 14 : Characterization of silver hybrid nanoparticles with a size of about 80 nm (a) TEM image, (b) UV absorption spectrum, (c) alcohol-phase emulsion photo.

[0088] Figure 15 : Characterization of gold hybrid nanoparticles with a size of about 50 nm (a) TEM image, (b) UV absorption spectrum, (c) aqueous-phase emulsion photo

[0089] Figure 16 : Characterization of gold hybrid nanoparticles with a size of about 70 nm: (a) TEM image, (b) UV absorption spectrum, (c) aqueous emulsion photograph

[0090] Figure 17 : Characterization of the reduction of p-nitrophenol catalyzed by silver hybrid nanoparticles with a size of about 20 nm:

[0091] (a) Change of UV-vis absorption spectrum with time, (b) Plot of Ct / C0 versus t (black) and -ln(Ct / C0) versus t (red) for the catalytic reaction.

[0092] Figure 18 : Characterization of the reduction of p-nitrophenol catalyzed by silver hybrid nanoparticles with a size of about 30 nm: (a) Change of UV-vis absorption spectrum with time, (b) Plot of Ct / C0 versus t (black) and -ln(Ct / C0) versus t (red) for the catalytic reaction.

[0093] Figure 19 : Characterization of the reduction of p-nitrophenol catalyzed by silver hybrid nanoparticles with a size of about 40 nm: (a) Change of UV-vis absorption spectrum with time, (b) Plot of Ct / C0 versus t (black) and -ln(Ct / C0) versus t (red) for the catalytic reaction.

[0094] Figure 20 : Characterization of the reduction of p-nitrophenol catalyzed by silver hybrid nanoparticles with a size of about 50 nm: (a) Change of UV-vis absorption spectrum with time, (b) Plot of Ct / C0 versus t (black) and -ln(Ct / C0) versus t (red) for the catalytic reaction.

[0095] Figure 21 : Characterization of the reduction of p-nitrophenol catalyzed by silver hybrid nanoparticles with a size of about 60 nm: (a) Change of UV-vis absorption spectrum with time, (b) Plot of Ct / C0 versus t (black) and -ln(Ct / C0) versus t (red) for the catalytic reaction.

[0096] Figure 22 : Characterization of the reduction of p-nitrophenol catalyzed by silver hybrid nanoparticles with a size of about 70 nm: (a) Change of UV-vis absorption spectrum with time, (b) Plot of Ct / C0 versus t (black) and -ln(Ct / C0) versus t (red) for the catalytic reaction.

[0097] Figure 23: Characterization of the reduction of p-nitrophenol catalyzed by silver hybrid nanoparticles with a size of about 80 nm: (a) Variation of the UV-vis absorption spectrum with time, (b) Plots of Ct / C0 vs. t (black) and -ln(Ct / C0) vs. t (red) for the catalytic reaction.

[0098] Figure 24 : Photos of the p-nitrophenol reduction reaction: (a) Photo of the p-nitrophenol solution before the reaction, (b) Photo of p-aminophenol after the reaction.

[0099] Figure 25 : Characterization of the recyclability of the reduction of p-nitrophenol catalyzed by silver hybrid nanoparticles with a size of about 80 nm: (a)-(j) are the plots of the variation of the UV-vis absorption spectrum with time for the first time and the silver hybrid nanoparticles recycled 1-9 times, respectively.

[0100] Figure 26 : Characterization of the recyclability of the reduction of p-nitrophenol catalyzed by silver hybrid nanoparticles with a size of about 80 nm: (a)-(j) are the plots of Ct / C0 vs. t (black) and -ln(Ct / C0) vs. t (red) for the first time and the silver hybrid nanoparticles recycled 1-9 times, respectively.

[0101] Figure 27 : Characterization of the recyclability of the reduction of p-nitrophenol catalyzed by silver hybrid nanoparticles with a size of about 20 nm: (a)-(k) are the plots of the variation of the UV-vis absorption spectrum with time for the first time and the silver hybrid nanoparticles recycled 1-10 times, respectively.

[0102] Figure 28 : Characterization of the recyclability of the reduction of p-nitrophenol catalyzed by silver hybrid nanoparticles with a size of about 20 nm: (a)-(k) are the plots of Ct / C0 vs. t (black) and -ln(Ct / C0) vs. t (red) for the first time and the silver hybrid nanoparticles recycled 1-10 times, respectively. Detailed implementation mode

[0103] In the following description, numerous specific details are given to provide a more thorough understanding of the present invention. However, it is obvious to those skilled in the art that the present invention can be implemented without one or more of these details. In other examples, some well-known technical features are not described to avoid confusion with the present invention.

[0104] Examples

[0105] Raw materials

[0106] Reagents and drugs for which the preparation methods are not mentioned in the present invention are all purchased from Aldrich and used directly.

[0107] Testing instrument

[0108]

[0109] Dynamic light scattering: 25 μL of the emulsion obtained after the polymerization reaction was dispersed in 2 mL of ethanol, transferred to a cuvette, and then tested with a dynamic light scattering instrument.

[0110] Ultraviolet absorption spectrum: 50 μL of the emulsion after the polymerization reaction was taken in a centrifuge tube, then 2 mL of absolute ethanol was added, shaken and mixed evenly, and transferred to a cuvette to measure the ultraviolet absorption spectrum.

[0111] Synthesis example 1

[0112] Synthesis of MAEBA

[0113] Sodium hydroxide (5.9 g, 0.15 mol), potassium iodide (30.5 g, 0.25 mol), and p-hydroxybenzaldehyde (15 g, 0.12 mol) were dissolved in 100 mL of absolute ethanol. The reaction system was heated to 70 °C, and bromoethanol (30.5 g, 0.25 mol) was added dropwise to the system, and the reaction continued for 36 h. After the reaction was completed, ethanol in the system was removed by vacuum distillation, and then a small amount of dichloromethane was added to dissolve. The crude product was purified by silica gel column chromatography (the eluent ratio was ethyl acetate: petroleum ether = 1:1), and 11.5 g of a transparent oily liquid was obtained after purification. The yield was calculated by 1 HNMR to be 76%, and the structural formula is as follows:

[0114]

[0115] The above product (11.5 g, 0.07 mol) and triethylamine (14.7 g, 0.14 mol) were dissolved in 100 mL of dichloromethane, and a dichloromethane solution of methacryloyl chloride (10.8 g, 0.11 mol) was slowly added dropwise. After reacting for 24 h, the solid in the system was filtered off, washed, and dried to obtain a crude product. The crude product was purified by silica gel column chromatography (the eluent ratio was ethyl acetate: petroleum ether = 1:3), and a white solid was obtained after purification. It was recrystallized at -20 °C and dried overnight, and finally 7.2 g of a white solid powder was obtained. The yield was calculated by 1 HNMR to be 63%, and the structural formula is as follows:

[0116]

[0117] Synthesis example 2

[0118] Synthesis of the macromolecular chain transfer agent PDMAEMA with an average degree of polymerization of 37 37

[0119] ​Weigh dimethylaminoethyl methacrylate (DMAEMA) (2.20 g, 14 mmol), 4-cyano-4-(thiobenzoyl) pentanoic acid (CPADB) (97.7 mg, 0.35 mmol), and AIBN (5.74 mg, 0.035 mmol) and dissolve them in anhydrous tetrahydrofuran (THF) (2.59 ml). Transfer the reaction system to a Schlenk tube and perform three cycles of freezing - evacuating - dissolving. Place the Schlenk tube at 70 °C and react for 12 h. Then, quench the reaction by placing the Schlenk tube in cold water. After diluting the reaction solution with a small amount of tetrahydrofuran, slowly add the reaction solution dropwise to a large amount of vigorously stirred n - hexane solution. Filter to collect the solid product and dry it overnight. Obtain a pink solid PDMAEMA 37 1.56 g, with a yield of 1 71% calculated by HNMR.

[0120] Synthesis Example 3

[0121] Synthesis of a macromolecular chain transfer agent PDMAEMA with an average degree of polymerization of 60 60

[0122] Weigh DMAEMA (2.26 g, 14 mmol), 4-cyano-4-(thiobenzoyl) pentanoic acid (CPADB) (33.48 mg, 0.12 mmol), and AIBN (1.97 mg, 0.012 mmol) and dissolve them in anhydrous tetrahydrofuran (2.58 ml). Transfer the reaction system to a Schlenk tube and perform three cycles of freezing - evacuating - dissolving. Place the Schlenk tube at 70 °C and react for 12 h. Then, quench the reaction by placing the Schlenk tube in cold water. After diluting the reaction solution with tetrahydrofuran, slowly add the reaction solution dropwise to a large amount of vigorously stirred n - hexane solution. Filter to collect the solid product and dry it overnight. Obtain a pink solid PDMAEMA 60 1.51 g, with a yield of 1 67% calculated by HNMR.

[0123] Synthesis Examples 4 - 8

[0124] Preparation of a block polymer with a macromolecular chain transfer agent PDMAEMA as the main chain 60

[0125] The product PDMAEMA of Synthesis Example 3 60 ​​(0.0194 g, 0.002 mmol), the product MAEBA of Synthesis Example 1 in different amounts, and AIBN (the molar ratio of PDMAEMA to AIBN is 1:0.2) were dissolved in absolute ethanol (the total solid content of the reaction system was 10%). The above solution was transferred to a Schlenk tube, and after three cycles of freezing - evacuating - dissolving, the Schlenk tube was sealed. The Schlenk tube was placed in an oil bath at 70 °C. After reacting for 24 h, the Schlenk tube was quenched with cold water to obtain a white emulsion, and the polymer nanoparticles were named PN1 - PN5. The molar ratio of PDMAEMA to MAEBA in each synthesis example during the reaction (under the conditions of the examples of the present invention, the monomer conversion rate of MAEBA was close to 100%, and the molar ratio of PDMAEMA to MAEBA in the block copolymer was also approximately equal to the feeding ratio, the same below) and the particle size of the obtained product nanoparticles (measured by a dynamic light scattering instrument) are shown in Table 1. The product photos, electron micrographs (taken by a transmission electron microscope), and particle size distribution diagrams are shown in Figures 1 to 5 .

[0126] Table 1

[0127]

[0128] Synthesis Examples 9 - 10

[0129] Preparation of block polymers with a macromolecular chain transfer agent PDMAEMA 37 as the main chain

[0130] The product PDMAEMA of Synthesis Example 2 37 (0.0122 g, 0.002 mmol), the product MAEBA of Synthesis Example 1 in different amounts, and AIBN (the molar ratio of PDMAEMA to AIBN is 1:0.2) were dissolved in absolute ethanol (the total solid content of the reaction system was 10%). The above solution was transferred to a Schlenk tube, and after three cycles of freezing - evacuating - dissolving, the Schlenk tube was sealed. The Schlenk tube was placed in an oil bath at 70 °C. After reacting for 24 h, the Schlenk tube was quenched with cold water to obtain a white emulsion, and the polymer nanoparticles were named PN6 and PN7. The molar ratio of PDMAEMA to MAEBA in each synthesis example during the reaction and the particle size of the obtained product nanoparticles (measured by a dynamic light scattering instrument) are shown in Table 2. The product photos (the solid content was 10 wt%, the same below), electron micrographs (taken by a transmission electron microscope), and particle size distribution diagrams are shown in Figures 6 to 7 .

[0131] Table 2

[0132]

[0133] It can be seen that, under the same other reaction conditions, the MAEBA content increases, the particle size of the polymer nanoparticles increases, and the polymer nanoparticles prepared by the method of the present invention have a uniform and narrow particle size distribution.

[0134] Example 1

[0135] Preparation of silver / polymer hybrid nanoparticles

[0136] The polymer nanoparticles PN1 to PN7 (0.0002 mmol, 25 μl) prepared in the synthesis example were mixed with AgNO 3 The solution (0.5 ml, 1 mmol / L) was mixed, stirred in an ice water bath for 8 h, and sodium borohydride solution (5 μl, 0.1 mol / L) was slowly added dropwise, and stirred for 2 h to obtain silver / polymer hybrid nanoparticles HPN1 to HPN7. In the embodiment of the present invention, the metal compound is substantially completely converted into a metal element (the same below). The electron microscope images (taken by transmission electron microscope), ultraviolet absorption spectra and photos of HPN1 to HPN7 are shown in FIG. Figures 8 to 14 As shown, since the metal particle size is basically negligible, the particle size of the metal / polymer hybrid nanoparticles obtained in the present invention is substantially the same as the particle size of the corresponding polymer nanoparticles (the same below).

[0137] Example 2

[0138] Preparation of gold / polymer hybrid nanoparticles

[0139] The polymer nanoparticles PN4 and PN6 (0.0002 mmol, 25 μL) prepared in the synthesis example were mixed with HAuCl 4 The solution (0.5 ml, 1 mmol / L) was mixed, stirred in an ice-water bath for 12 h, and sodium borohydride solution (5 μL, 0.1 mol / L) was slowly added dropwise and stirred for 2 h to obtain gold / polymer hybrid nanoparticles HPN8 and HPN9. The electron micrograph (taken by transmission electron microscope), UV absorption spectrum and photos of HPN8 and HPN9 are shown in Figure 15 and Figure 16 shown.

[0140] From the ultraviolet absorption spectrum, we can see that since the absorption peak of gold is at 250-400nm and the absorption peak of silver is at 400-500nm (when the particle size of nanoparticles increases, the absorption peak will move toward the long wavelength direction), Figures 8 to 16 It can be seen that the present invention successfully synthesized metal / polymer hybrid nanomaterials loaded with gold or silver nanoparticles.

[0141] Embodiment 3-9

[0142] Take 3 mL of the prepared mixed solution of p-nitrophenol (4-NP) (0.1 mmol / L) and sodium borohydride (20 mmol / L) in a cuvette, add silver / polymer hybrid nanoparticles HPN1 to HPN7 (100 μL, 0.00001 mmol) for catalytic reaction to reduce p-nitrophenol to p-aminophenol.

[0143] Test Example 1 Catalytic Reaction Kinetics Test

[0144] During the reaction process of Example 3, after the addition of catalysts HPN1 to HPN7, immediately scan with a UV-vis spectrophotometer every 2 min in the wavelength range of 250 - 500 nm. The results are as shown in Figures 17 to 23 Figure (a) therein. It can be seen that after the addition of silver / polymer hybrid nanoparticles, the ultraviolet absorption peak of the nitro group at 400 nm gradually decreases with the progress of the reaction, and the ultraviolet absorption peak of the amino group at 300 nm gradually increases with the progress of the reaction. However, since the ultraviolet absorption peak of the hybrid nanoparticles is at 270 nm, it will interfere with the ultraviolet absorption result of the amino group. Therefore, we mainly judge the catalytic effect by observing the change of the ultraviolet absorption peak of the nitro group with time. As can be seen from the figure, silver / polymer hybrid nanoparticles have good catalytic effect on this reaction. Taking the reaction time t as the abscissa and Ct / C0 and -ln(Ct / C0) as the ordinates respectively for plotting (as shown in Figures 17 to 23 Figure (b) therein, where Ct is the concentration of p-nitrophenol at time t and C0 is the initial concentration of p-nitrophenol). Because in the reduction reaction, the amount of NaBH 4 is far more than that of 4-NP, it can be approximately considered that the concentration of borohydride ions remains unchanged, and thus the whole reduction reaction is regarded as a pseudo-first-order reaction. -ln(Ct / C0) has a linear relationship with time, which conforms to the pseudo-first-order reaction kinetic equation. The apparent reaction rate constant k can be calculated from the change of 4-NP concentration with time. The results are shown in Table 3. It can be seen that the hybrid nanoparticles with particle sizes of about 20 and 80 nm have faster catalytic efficiency.

[0145] Table 3

[0146] Example 3 4 5 6 7 8 9 Catalyst type HPN1 HPN2 HPN3 HPN4 HPN5 HPN6 HPN7 k value 0.39684 0.19074 0.1759 0.13161 0.31924 0.30406 0.61198

[0147] Among them, take the samples of Example 3 to take photos before and after the reaction as shown in Figure 24 shown.

[0148] Test Example 6 Catalyst Recycling Performance

[0149] Take the reaction systems after the reactions of Example 3 and Example 9, and continue to repeatedly add the same mass of 4-NP and NaBH 4, the catalyst circulation test was carried out, and the ultraviolet absorption spectrum was measured and the apparent reaction rate constant k was calculated according to the method of Test Example 1. The results are as Figures 25 to 28 shown. Among them, Figures 25 to 26 (a)-(j) in represent the test results of Example 9 and repeated experiments 1-9 times; Figures 27 to 28 (a)-(k) in represent the test results of Example 3 and repeated experiments 1-10 times. It can be seen that the catalyst of the present invention has good circulation performance and can be recycled at least more than 10 times.

[0150] For the above embodiments, all technical solutions falling within the idea of the present invention belong to the protection scope of the present invention. It should be pointed out that for those of ordinary skill in the art, several improvements and modifications made without departing from the principle of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. A metal-polymer hybrid nanoparticle, comprising a block polymer containing the following polymer segment a and polymer segment b and a metal: (A) contains a polymer segment a obtained by polymerizing at least one nitrogen-containing monomer, wherein the nitrogen-containing monomer has a structural formula as shown in formula (I): (B) contains a polymer segment b obtained by polymerization of at least one nucleating monomer, wherein the structural formula of the nucleating monomer is as shown in formula (II): in: R1 of each nitrogen-containing monomer may be the same or different and are independently selected from H or methyl; R2 of each nitrogen-containing monomer may be the same or different and is independently selected from C substituted by R4 1-10 wherein R4 is selected from amino, di(C 1-5 At least one of an alkyl) amino group, a pyridyl group, a pyrrolyl group, an imidazolyl group, a pyrazolyl group, an oxazolyl group, a pyrimidinyl group, an indolyl group, a pyrazinyl group, a quinolyl group or an isoquinolyl group; The R3 of each nucleating monomer may be the same or different and are independently selected from C 1-10 Alkyl, C containing 1-20 oxygen atoms 1-25 Oxoalkyl, 1-5 hydroxy substituted C 1-10 Alkyl, or R5 substituted C 1-10 wherein R5 is selected from at least one of acetylacetonate, phenyl, naphthyl, phenoxy, naphthyl, tetrahydrofuranyl, p-benzaldehyde or p-ethoxybenzaldehyde; The content of polymerized repeating units derived from nitrogen-containing monomers in the block polymer is 5-90 mol%; The content of polymerized repeating units derived from the nucleating monomer in the block polymer is 10-95 mol%; The metal is selected from at least one of gold, silver, palladium, iron or ruthenium; The content of the metal in the metal-polymer hybrid nanoparticles is 0.01-10 wt %.

2. The metal-polymer hybrid nanoparticle according to claim 1, wherein R2 is selected from at least one of the following groups: The R3 is selected from at least one of the following groups:

3. The metal-polymer hybrid nanoparticle according to claim 1, wherein the nitrogen-containing monomer is The nucleating monomer is 4. The metal-polymer hybrid nanoparticle according to any one of claims 1 to 3, wherein: The metal is selected from gold or silver, preferably silver; Preferably, the content of polymerized repeating units derived from nitrogen-containing monomers in the block polymer is 20-80 mol%, more preferably 25-70 mol%; Preferably, the content of polymerized repeating units derived from the nucleating monomer in the block polymer is 20-80 mol%, more preferably 30-75 mol%; Preferably, the content of the metal in the metal-polymer hybrid nanoparticles is 0.5-5 wt %. 5 . The metal-polymer hybrid nanoparticles according to claim 1 , wherein the particle size of the metal-polymer hybrid nanoparticles is 10-99 nm, preferably 15-92 nm, and more preferably 20-88 nm.

6. The method for preparing the metal-polymer hybrid nanoparticles according to any one of claims 1 to 5, comprising the following steps: (S1) polymerizing a nitrogen-containing monomer by a living free radical polymerization method to obtain a macroinitiator comprising a polymer segment a; (S2) polymerizing the macromolecular initiator and the nucleating monomer in step S1 by a polymerization-induced self-assembly method to obtain block copolymer nanoparticles comprising a polymer segment a and a polymer segment b; (S3) reacting the block copolymer nanoparticles obtained in step S2 with a metal compound to obtain metal-polymer hybrid nanoparticles.

7. The method according to claim 6, wherein: In step S2, the molar ratio of the macromolecular initiator to the nucleating monomer is 1:20-1:150; Preferably, in step S3, the mass ratio of the block copolymer nanoparticles to the metal compound is 1:0.001-1:

1.

8. Use of the metal-polymer hybrid nanoparticles as claimed in any one of claims 1 to 5 or the metal-polymer hybrid nanoparticles prepared by the method for preparing the metal-polymer hybrid nanoparticles as claimed in any one of claims 6 to 7 as a chemical reaction catalyst.

9. The use according to claim 8, wherein the chemical reaction is selected from at least one of an oxidation reaction, a reduction reaction, a hydrogenation reaction, a hydrogen evolution reaction or an electrochemical reaction.

10. The use according to claim 8, wherein the chemical reaction is a catalytic reduction reaction of 4-nitrophenol, and preferably, the amount of the catalyst is 0.1-20wt% of the mass of 4-nitrophenol, preferably 1-5wt%.

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