Gold-platinum-silver ternary metal nano heterogeneous material as well as preparation method and application thereof

Abstract

The invention discloses a gold-platinum-silver ternary metal nano heterogeneous material and a preparation method and application thereof, in the gold-platinum-silver ternary metal nano heterogeneous material, platinum and silver alloy is obliquely distributed at one end of a gold nanorod to form an asymmetric structure deviating to one side; the preparation method specifically comprises the following steps: firstly, preparing anisotropic gold nanorods as raw materials, and coating the anisotropic gold nanorods with silver nanoshell layers to obtain Au-coated Ag core-shell structure nanoparticles; and then adding a surfactant, chloroplatinic acid and an ascorbic acid solution into the core-shell structure nanoparticles, and realizing inclined distribution of platinum and silver at one end of a gold rod by regulating and controlling the thickness of a silver layer and regulating and controlling the etching and deposition rate in an electric replacement reaction process, so as to finally obtain the nano material disclosed by the invention. The nano material provided by the invention is novel in structure, simple and convenient in preparation method and high in controllability, can accurately regulate and control optical properties, and has wide application prospects in the fields of photo-thermal therapy, photo-thermal catalysis and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of nanomaterials, and in particular relates to a gold-platinum-silver ternary metal nano heterogeneous material and a preparation method and application thereof. Background Art

[0002] In recent years, plasmonic nanomaterials based on precious metals (such as gold, silver, platinum, etc.) have shown broad application prospects in many fields such as catalysis, biosensing, environmental monitoring, and energy conversion due to their unique optoelectronic properties. Precious metal materials have excellent surface plasmon resonance effects, which give them significant advantages in electromagnetic field enhancement, signal amplification, and photothermal conversion. Among them, multi-component plasmonic nanoheterostructures are precise combinations of different precious metals or other functional materials at the nanoscale, which can effectively utilize the advantages of each component and further enhance and expand the functions and application scenarios of plasmonic nanomaterials through synergistic effects between components.

[0003] The structural morphology of plasmonic composite nanoparticles is a key factor affecting their physical and chemical properties. Therefore, regulating the morphology of composite nanoparticles is crucial to achieve performance regulation and optimization. At present, most of the precious metal nanoheterostructures prepared by chemical methods are uniformly coated core-shell nanostructures. Although dumbbell-shaped, dandelion-shaped and other shapes can be achieved by regulating experimental parameters such as the amount of surfactant and the amount of metal precursor, the morphology and component regulation of asymmetric heterogeneous nanoparticles are still very limited, which greatly limits their application scenarios. This is because in the actual preparation process, multi-component plasmonic heterostructures often involve multi-step chemical reactions such as reduction nucleation, growth and maturation of different metal precursors, and their intrinsic growth mechanism is relatively complex. Therefore, there are still huge challenges in accurately constructing asymmetric nanoheterostructures, especially accurately controlling the precise deposition of the number of sites of heterostructures on nanoplatforms, and realizing precise control of asymmetric nanoheterostructures. Summary of the invention

[0004] The first object of the present invention is to provide a method for preparing a gold-platinum-silver ternary metal asymmetric nano heterogeneous material in view of the shortcomings of the prior art.

[0005] The preparation method of the gold-platinum-silver ternary metal asymmetric nano heterogeneous material of the present invention specifically adopts the following technical scheme: Step (1): gold nanoparticles prepared by seed-mediated method; Step (2): washing and purifying the gold nanoparticles by centrifugation, re-dispersing them in a hexadecyltrimethylammonium chloride solution, adding silver nitrate and ascorbic acid, and reacting to obtain an Au@Ag core-shell nanoparticle structure; in the Au@Ag core-shell nanoparticle structure, the thickness of the Ag shell layer is 2-7 nm, 7-10 nm, or 10-14 nm; Step (3): The core-shell nanoparticles are purified by centrifugation and redispersed in a hexadecyltrimethylammonium bromide solution, chloroplatinic acid and ascorbic acid are added, and the gold-platinum-silver ternary metal asymmetric nanoheterogeneous material is obtained after standing for reaction.

[0006] Step (2) and step (3) are specifically as follows: a certain amount of gold nanorods in step (1) are centrifugally washed and purified, and redispersed in the same volume of hexadecyltrimethylammonium chloride solution, and then silver nitrate and ascorbic acid of the same concentration and different volumes are added respectively, and reacted at 60° C. for 4 hours under stirring. Then, the gold nanorods are centrifugally purified, and redispersed in the same volume of hexadecyltrimethylammonium bromide solution, and then chloroplatinic acid and ascorbic acid are added, and the reaction is allowed to stand at 30° C. for 16 hours, followed by centrifugation and washing, to obtain a gold-platinum-silver ternary metal nano heterogeneous material.

[0007] Preferably, in step (1), the gold nanoparticles include but are not limited to gold nanorods, gold triangles, gold cones and other geometric shapes.

[0008] Preferably, in step (1), the gold nanorods are washed by centrifugation at 5000 rpm for 10 minutes.

[0009] Preferably, in step (2), the molar concentration ratio of silver nitrate to ascorbic acid is 1:9-10, more preferably 1:10.

[0010] Preferably, in step (2), the volume ratio of silver nitrate to ascorbic acid is 2:1-1.5, more preferably 2:1.

[0011] Preferably, in step (2), the thickness of the Ag shell is regulated by adjusting the volume ratio of the gold nanorods to the silver nitrate. Specifically, when the volume ratio of the gold nanorods to the silver nitrate is 5 mL:80-120 uL, 5 mL:120-220 uL and 5 mL:220-400 uL, respectively, the corresponding thickness ranges of the Ag shell are 2-7 nm, 7-10 nm and 10-14 nm.

[0012] Preferably, in step (2), the centrifugal washing operation after the reaction for 4 hours is: 8000 rpm, 10 minutes.

[0013] Preferably, in step (3), the volume ratio of chloroplatinic acid to ascorbic acid is 1-1.2, more preferably 1:1.

[0014] Preferably, in step (3), the molar concentration ratio of chloroplatinic acid to ascorbic acid is 1-1.5:10, and the concentration range of chloroplatinic acid is 0.08-0.2 mM.

[0015] Preferably, in step (3), the centrifugal washing operation after the reaction for 16 hours is: 8000 rpm, 10 minutes.

[0016] The second object of the present invention is to provide a gold-platinum-silver ternary metal asymmetric nano heterogeneous material, which is prepared by the above method, wherein platinum and silver elements are distributed obliquely at one end of the gold nanoparticle in a branch-like form to form an asymmetric structure biased to one side.

[0017] The third object of the present invention is to provide the use of the above-mentioned gold-platinum-silver ternary metal asymmetric nanoheterogeneous material as a photothermal therapy material.

[0018] Compared with the prior art, the beneficial effects of the present invention are at least: 1) The Au-Pt-Ag ternary composite nano heterogeneous material prepared by the present invention has a unique asymmetric structure (such as sickle-shaped), which has not been reported so far. Compared with traditional dumbbell-shaped nanoparticles, this structure has a better photothermal effect.

[0019] 2) The preparation method of the ternary composite heterogeneous material provided in the present invention has strong controllability, high yield, and good universality. By adjusting the thickness of the Ag sacrificial template, the etching and deposition rates in the reaction process can be precisely controlled to achieve precise control of the etching-induced Pt-Ag deposition site. When the Ag shell thickness is 2-7 nm, the Ag etching rate is similar to the Pt-Ag alloy reduction deposition rate, and the reduced nanoparticles are symmetrically deposited on the ends of the high curvature of the gold rod, forming a dumbbell shape; when the Ag shell thickness increases to 7-10 nm, the etching rate is greatly accelerated and the etching symmetry is broken. At this time, the Pt-Ag alloy tends to deposit nanoparticles at one end and undergo a ripening effect, and the prepared nanoparticles are dandelion-shaped; when the Ag shell thickness is further increased to 10-14 nm, an asymmetric etching effect is still shown at this time, and because the alloy deposition rate is slower and its site selectivity is higher, it is only deposited at one corner of the end of the gold rod after ripening, that is, a sickle-shaped. In addition to gold nanorods as platforms, it can also be applied to gold nanotriangles, gold nanocubes and other nanoplatforms to achieve the construction of ternary nanoheterostructures with different morphologies. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Flow chart for the synthesis of Au-Pt-Ag ternary metallic nanoheterogeneous materials.

[0021] Figure 2 (ac) are TEM images of Au@Ag shells with thicknesses of 5nm, 9nm, and 11nm; (df) are Figure 2 (ac) TEM images of Au-Pt-Ag ternary metal nanoheterogeneous materials synthesized at corresponding shell thicknesses Figure 3 (ab) are the TEM images and high-resolution images of sickle-shaped gold-platinum-silver ternary metal nanoheterogeneous materials, respectively; (c) is the elemental analysis diagram; (df) are the elemental analysis diagrams of Au, Ag, and Pt, respectively.

[0022] Figure 4 TEM images of three types of Au-Pt-Ag ternary composite nanoheterogeneous materials synthesized by replacing gold nanorods with micro-gold nanorods, among which (a) is dumbbell-shaped, (b) is dandelion-shaped, and (c) is sickle-shaped.

[0023] Figure 5 for Figure 2 (f) The ultraviolet absorption spectrum of the Au-Pt-Ag ternary composite nanoheterogeneous material and the temperature rise trajectory of the photothermal effect, where (a) is the ultraviolet absorption spectrum and (b) is the temperature rise trajectory.

[0024] Figure 6 shows the TEM images of the site-specific growth of gold triangle flakes, and (ac) are the TEM images of the deposition of 3 corners, 2 corners, and 1 corner, respectively. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0026] like Figure 1 As shown, the present invention discloses an etching-induced fixed-point growth plasmon nanomaterial and a preparation method thereof, specifically: Step (1): Prepare gold nanorods with an aspect ratio of 2.8 to 4.2 using a seed-mediated method: Freshly prepared NaBH4 (0.01 M, 6 mL) was quickly added to HAuCl4.3H2O (0.5 mM, 5 mL) and CTAB. (0.2M, 5 mL). The color of the solution was observed to change from yellow to brown. The seed solution was aged at room temperature for 30 minutes before use. Next, the growth solution was prepared by adding AgNO3 (4 mM, 960 uL) to a mixed solution containing 0.28 g CTAB and 0.0494 g NaOL. After standing at 30°C for 15 minutes, HAuCl4.3H2O (0.5 mM, 5 mL) solution was added. Then, HCl (1 M, 216 uL) was added after stirring (700 rpm) for 10 minutes to adjust the pH of the growth solution. Then, after slowly stirring at 400 rpm for 15 minutes, AA (0.01 M, 25 uL) was added and the solution was vigorously stirred for 30 seconds. Finally, 32 uL of the seed solution was quickly injected into the growth solution. The resulting mixture was stirred for 30 seconds and then stood at 30°C for 12 hours for the growth of gold nanoparticles (AuNRs). Subsequently, the resulting solution was centrifuged at 8000 rpm for 10 minutes and redispersed in deionized water for subsequent use.

[0027] Step (2): Take 5 mL of the gold nanorods prepared in step (1), wash them with water, centrifuge them at 5000 rpm for 10 min twice, redisperse them in an equal volume of water, and then add them to a CTAB (3 mM, 6 mL) solution. Then, add AgNO3 (0.01 M, 80-120 uL, 120-220 uL or 220-400 uL) and ascorbic acid AA (0.1 M, 125 uL) in sequence. Stir in a water bath at 60 °C for 4 hours to obtain a mixture containing an Au@Ag core-shell nanorod structure.

[0028] Step (3): HPtCl (1 mM, 100 uL) and AA (0.01 M, 100 uL) were added to the mixture in sequence, and the mixture was allowed to stand in a 30°C water bath for 14 hours. The obtained solution was then centrifuged once at 8000 rpm for 10 min and redispersed in deionized water to obtain dumbbell-shaped, dandelion-shaped or sickle-shaped gold-platinum-silver ternary metal nanoheterogeneous materials.

[0029] The technical solution of the present invention is further explained below in conjunction with several preferred embodiments, but the experimental conditions and setting parameters therein should not be regarded as limitations on the basic technical solution of the present invention, and the protection scope of the present invention is not limited to the following embodiments.

[0030] Example 1: Synthesis of dumbbell-shaped gold-platinum-silver ternary metal nanoheterogeneous materials Step (1): Prepare gold nanorods with an aspect ratio of 2.8 to 4.2 using a seed-mediated method Step (2): Take 5 mL of the gold nanorods prepared in step (1), wash with water, centrifuge at 5000 rpm for 10 min twice, redisperse in an equal volume of water, and then add to CTAB (3 mM, 6 mL) solution, add AgNO3 (0.01 M, 80 uL) and AA (0.1 M, 40 uL) in sequence, and stir in a 60 °C water bath for 4 hours to obtain a mixture containing an Au@Ag core-shell nanorod structure, wherein the Au@Ag shell thickness is 5 nm.

[0031] Step (3): Add H2PtCl6 (1 mM, 95 uL) and AA (0.01 M, 95 uL) to the mixture in sequence, and place it in a 30°C water bath for 14 hours. Then, centrifuge the obtained solution once at 8000 rpm for 10 min and redisperse it in deionized water to obtain a dumbbell-shaped gold-platinum-silver ternary metal nanoheterogeneous material.

[0032] Example 2: Synthesis of Dandelion-type Gold-Platinum-Silver Ternary Metal Nanoheterogeneous Materials Step (1): Prepare gold nanorods with an aspect ratio of 2.8 to 4.2 using a seed-mediated method Step (2): Take 5 mL of the gold nanorods prepared in step (1), wash with water, centrifuge at 5000 rpm for 10 min twice, redisperse in an equal volume of water, and then add to CTAB (3 mM, 6 mL) solution, add AgNO3 (0.01 M, 120 uL) and AA (0.1 M, 60 uL) in sequence, and stir in a 60 °C water bath for 4 hours to obtain a mixture containing an Au@Ag core-shell nanorod structure, wherein the Au@Ag shell thickness is 9 nm.

[0033] Step (3): Add H2PtCl6 (1 mM, 95 uL) and AA (0.01 M, 95 uL) to the mixture in sequence, and place it in a 30°C water bath for 14 hours. Then, centrifuge the obtained solution once at 8000 rpm for 10 min and redisperse it in deionized water to obtain dandelion-type gold-platinum-silver ternary metal nanoheterogeneous materials.

[0034] Example 3: Synthesis of sickle-shaped gold-platinum-silver ternary metal nanoheterogeneous materials Step (1): Prepare gold nanorods with an aspect ratio of 2.8 to 4.2 using a seed-mediated method: Step (2): Take 5 mL of the gold nanorods prepared in step (1), wash with water, centrifuge at 5000 rpm for 10 min twice, redisperse in an equal volume of water, and then add CTAB (3 mM, 6 mL) solution, add AgNO3 (0.01 M, 220 uL) and AA (0.1 M, 125 uL) in sequence, stir in a 60 °C water bath for 4 hours, and obtain a mixture containing an Au@Ag core-shell nanorod structure, wherein the Au@Ag shell thickness is 11 nm.

[0035] Step (3): HPtCl (1 mM, 100 uL) and AA (0.01 M, 100 uL) were added to the mixture in sequence, and the mixture was allowed to stand in a 30°C water bath for 14 hours. The obtained solution was then centrifuged once at 8000 rpm for 10 min and redispersed in deionized water to obtain sickle-shaped gold-platinum-silver ternary metal nanoheterogeneous materials.

[0036] In Examples 1-3, the TEM images of the Au@Ag core-shell nanorod structures obtained in step (2) are as follows: Figure 2 As shown in (a)-(c) in the figure, the TEM images of the synthesized gold-platinum-silver ternary metal nanoheterogeneous materials at the corresponding shell thickness are shown in Figure 2 As shown in (d)-(f) in the figure.

[0037] The elemental analysis of the sickle-shaped gold-platinum-silver ternary metal nanoheterogeneous material obtained in Example 3 is shown in FIG. Figure 3 shown.

[0038] Example 4: Synthesis of dumbbell-shaped, dandelion-shaped and sickle-shaped gold-platinum-silver ternary metal nanoheterogeneous materials using micro-gold nanorods as seeds In a typical implementation case of the present invention, the present invention can be implemented by the following technical solutions: Step (1): A seed-mediated method is used to prepare gold nanorods with an aspect ratio of 2.7 to 7.32, a diameter of 7 to 11 nm, and a length of 60 to 70 nm.

[0039] Step (2): Take 5 mL of the gold nanorods in step (1), wash with water, centrifuge at 10000 rpm, 10 min twice, redisperse in an equal volume of water, and then add to CTAB (3mM, 6 mL) solution, and then add AgNO3 (0.01 M, 80 uL, 160 uL, 240 uL) and AA (0.1M, 40 uL, 80 uL, 120 uL) in sequence, and stir in a 60 ℃ water bath for 4 hours.

[0040] Step (3): After 4 hours, H2PtCl6 (1 mM, 95 uL) and AA (0.01 M, 95 uL) were added to the mixture in sequence, and the mixture was allowed to stand in a 30 °C water bath for 14 hours. The obtained solution was then centrifuged once at 8000 rpm for 10 min and redispersed in deionized water to obtain dumbbell-shaped, dandelion-shaped and sickle-shaped gold-platinum-silver ternary metal nanoheterogeneous materials, respectively.

[0041] The TEM image of the gold-platinum-silver ternary metal nanoheterogeneous material prepared in this example is as follows Figure 4 As shown, this proves that the method of the present invention has good universality and is not affected by the size or morphology of the original gold nanoparticles.

[0042] Example 5: Temperature rise trajectory and ultraviolet absorption spectrum of sickle-shaped gold-platinum-silver ternary metal nanomaterials with photothermal effect Step (1): Turn on the light source to irradiate the sample, start the data acquisition system synchronously, take 1 mL of the sickle-shaped gold-platinum-silver ternary metal nanoheterogeneous material synthesized in Example 3 and fix it under the laser, and record the surface and internal temperature of the sample at the initial time (t = 0); thereafter, automatically collect temperature data every 20 seconds, continuously monitor for 10 minutes, and observe the temperature change trend over time.

[0043] Step (2): After the experiment, turn off the light source and obtain the heating curve.

[0044] The results are as follows Figure 5 shown. Figure 5 (a) is the ultraviolet absorption spectrum, and its absorption peak is located in the near-infrared region (1000-1250 nm), indicating that the localized surface plasmon resonance (LSPR) of the ternary composite nanoheterogeneous material is mainly in the near-infrared range and can absorb light energy in the near-infrared region (NIR), and can be used for photothermal therapy or near-infrared optical applications. Figure 5 (b) is a temperature rise curve. The temperature of the material gradually increases with time under light irradiation, from room temperature (~25°C) to nearly 50°C, indicating that the material obtained by the present invention has significant photothermal conversion ability and has application potential in fields such as photothermal therapy.

[0045] Example 6: Synthesis of gold-platinum-silver ternary metal nanoheterogeneous materials grown on gold triangles Step (1): Prepare golden triangle sheets by seed-mediated method. Take CTAC (0.1 M, 9.3 mL), add HAuCl4 (0.02 M, 100 μL) under stirring, and prepare ice-cold NaBH4 (0.01 M, 50 mL). Take 450 μL and quickly add it to the former solution under stirring and stir vigorously for 2 min. Keep it at 30 °C for at least 2 h before use. Then add HAuCl4 (100 μL, 20 mM) and potassium iodide (25 μL, 0.01 M) to CTAC (0.1 M, 9.7 mL) and mix well until the solution is clear and transparent without flocs, which is recorded as solution A. HAuCl4 (300 μL, 20 mM) and potassium iodide (90 μL, 0.01 M) were added to CTAC (0.1 M, 29.1 mL) and mixed until the solution was clear and transparent without flocs, which was recorded as solution B. 0.04 M AA solution was prepared, and 185 μL and 500 μL were added to solutions A and B, respectively. Shake slowly until the solution changes from light yellow to colorless. Subsequently, the matured seed solution was diluted 10 times with 0.1 M CTAC, 250 μL was added to solution A, and the solution was shaken quickly and gently for about 5 s (room temperature 20 °C). Solution A turned into light pink purple. 150 μL was quickly added to solution B, and the solution was shaken gently for 10 s to make the solution smooth and uniform. It was left to stand at 20 °C for 10 min. Within 10 min, the color of the growth solution gradually changed from light pink purple to light blue, and finally to blue, indicating that the particle growth was completed.

[0046] Step (2): Take 5 mL of the golden triangle tablets in step (1), wash with water, centrifuge at 4000 rpm for 10 min twice, redisperse in an equal volume of water, and then add to CTAB (3mM, 6 mL) solution, and then add AgNO3 (0.01 M, 40uL, 80uL, 120uL) and AA (0.1M, 20uL, 40uL, 60uL) in sequence, and stir in a 60℃ water bath for 4 hours.

[0047] Step (3): After 4 hours, H2PtCl6 (1 mM, 60 uL) and AA (0.01 M, 60 uL) were added to the mixture in sequence, and the mixture was allowed to stand in a 30 °C water bath for 14 hours. The obtained solution was then centrifuged once at 4000 rpm for 10 min and redispersed in deionized water to obtain 3-corner, 2-corner and 1-corner deposited gold-platinum-silver ternary metal nanoheterogeneous materials, respectively.

[0048] The TEM image of the gold-platinum-silver ternary metal nanoheterogeneous material prepared in this example is as follows Figure 6 shown.

[0049] The above are only preferred embodiments of the present invention. It should be noted that the above preferred embodiments should not be regarded as limiting the present invention, and the protection scope of the present invention should be based on the scope defined by the claims. For ordinary technicians in this technical field, several improvements and modifications can be made without departing from the spirit and scope of the present invention, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A gold-platinum-silver ternary metal asymmetric nano heterogeneous material, characterized in that: The platinum and silver elements are distributed in a branch-like form at one end of the gold nanoparticles, forming an asymmetric structure that is biased to one side.

2. A method for preparing the gold-platinum-silver ternary metal asymmetric nano heterogeneous material as claimed in claim 1, characterized in that: The preparation method comprises the following steps: Step (1): preparing gold nanoparticles by seed-mediated method; Step (2): washing and purifying the gold nanoparticles by centrifugation, re-dispersing them in a hexadecyltrimethylammonium chloride solution, adding silver nitrate and ascorbic acid, and reacting to obtain Au@Ag core-shell nanoparticles; in the Au@Ag core-shell nanoparticles, the thickness of the Ag shell layer is 2-7 nm, 7-10 nm, or 10-14 nm; Step (3): The Au@Ag core-shell nanoparticles are purified by centrifugation, and redispersed in a hexadecyltrimethylammonium bromide solution, and chloroplatinic acid and ascorbic acid are added in a molar concentration ratio of 1 to 1.5:

10. After the reaction, the gold-platinum-silver ternary metal asymmetric nanoheterogeneous material can be obtained.

3. The preparation method according to claim 2, characterized in that: In step (2), the molar concentration ratio of silver nitrate to ascorbic acid is 1:9-10.

4. The preparation method according to claim 2, characterized in that: In step (2), the volume ratio of silver nitrate to ascorbic acid is 2:1-1.

5.

5. The preparation method according to claim 2, characterized in that: In step (2), the volume ratio of the gold nanorods to silver nitrate is 5 mL:80-120 uL, 5 mL:120-220 uL or 5 mL:220-400 uL.

6. The preparation method according to claim 2, characterized in that: In step (2), the reaction temperature is 60-65°C and the reaction time is 4-6h.

7. The preparation method according to claim 2, characterized in that: In step (3), the volume ratio of chloroplatinic acid to ascorbic acid is 1 to 1.

2.

8. The preparation method according to claim 2, characterized in that: In step (3), the concentration of chloroplatinic acid is 0.08-0.2 mM.

9. The preparation method according to claim 2, characterized in that: In step (3), the reaction temperature is 30-35°C and the reaction time is 16-18h.

10. Use of the gold-platinum-silver ternary metal asymmetric nanoheterogeneous material as claimed in claim 1 as a photothermal therapy material.

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