Preparation method of mesoporous silica-coated gold composite nanowires
The method of preparing mesoporous silica-coated gold nanowires in a one-pot reaction using sol-gel chemistry solves the problems of complex preparation and low cost-effectiveness in existing technologies, and realizes a simple preparation of mesoporous silica-coated gold nanowires with high yield.
Patent Information
- Application Number
- CN202311660293.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2023-12-06
- Publication Date
- 2026-01-09
- Estimated Expiration
- 2043-12-06
AI Technical Summary
Existing technologies make it difficult to efficiently prepare high-yield mesoporous silica-coated gold composite nanowires in a one-step process. Traditional methods are complex to operate and have poor cost-effectiveness.
A sol-gel chemical method was adopted, in which choline, hexadecyltrimethylammonium bromide, chloroauric acid and tetramethyl silicate were added in a one-pot reaction. Through the catalytic and reducing effects of choline, combined with the template effect of CTAB, mesoporous silica-coated gold nanowires were prepared in one step.
We have achieved efficient and simple preparation of Au@mesoporous SiO2 composite nanowires with a diameter of about 70-95 nanometers and a length of about 0.5-2 micrometers, with a yield of up to 95% and good control.
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Figure CN117380967B_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application belongs to the technical field of nanometer material preparation, and particularly relates to a preparation method of mesoporous silica coated gold composite nanowires (i.e. gold@mesoporous silica composite nanowires) with a length of about 70-95 nanometers and a length of about 0.5-2 micrometers. BACKGROUND
[0002] The gold@mesoporous silica (Au@mesoporous SiO2) core-shell structure composite nanowires have a dual function of different materials of the core and the shell, and a unique advantage of stabilizing Au nanowires, and have wide application values in many fields, such as catalysis, photoelectricity, adsorption, and chemical sensing and single molecule detection based on local plasma resonance.
[0003] The existing preparation method of traditional Au@mesoporous SiO2 composite nanowires mainly adopts two-step or multi-step method (see documents such as Catalytically active and thermally stable core-shell gold-silica nanorods for CO oxidation. RSC. Adv., 2021, 11, 11642; 3D plasmonic transducer based on gold nanoparticles produced by base ablation on silica nanowires. Appl. Phys. A (2016), 122:539; Sol-gel based materials for biomedical applications. Progress in Materials Science, 77 (2016), 1-79; Silica nanowires: Growth, integration, and sensing applications. Microchim Acta, 2014, 181, 1759-1780.). First, gold nanowires are prepared by a template method, such as using a porous anodic aluminum oxide film or a carbon nanotube as a template, and forming Au nanowires through electrochemical deposition, chemical vapor deposition or sol-gel deposition. Then, the Au nanowires are coated with a SiO2 shell, and finally Au@SiO2 composite nanowires are formed. Although this method can better control the size and uniformity of Au@SiO2 composite gold nanowires, it is cumbersome to operate, and the nanowires may be damaged during the template separation process. A non-template method is obviously a better choice, such as a typical liquid phase method. The principle is that under certain conditions, Au precursor molecules are mixed with suitable ligand molecules (such as surfactants), and due to the different occupation abilities of ligand molecules on different crystal faces of gold particles, there is a dominant crystal face in the growth process of Au nanoparticles. Therefore, the continuous reduction and growth of Au precursors on the dominant crystal face can eventually form one-dimensional Au nanowires. Then, the mesoporous SiO2 shell is coated. However, although this method is simple to operate, the cost performance of the synthesis of the multi-step operation is still poor.
[0004] In summary, it is still a challenge to prepare Au@mesoporous SiO2 composite nanowires by one-pot reaction and one-step operation. Based on this, the present application is developed. SUMMARY
[0005] The present application aims at overcoming the defects existing in the prior art, and provides a preparation method of mesoporous silica coated gold composite nanowires.
[0006] To achieve the above object, the present application adopts the following technical scheme:
[0007] The preparation method of mesoporous silica coated gold composite nanowires comprises the following steps: controlling the water temperature to be constant at 90-100 DEG C, adding choline solution, cetyltrimethylammonium bromide, chloroauric acid solution and tetramethyl orthosilicate under stirring condition, stirring and reacting for 2.5-3.5 hours under the condition of 90-100 DEG C, and obtaining the product through centrifugation and purification after the reaction is completed.
[0008] Specifically, in the reaction system, the concentration of choline is 9-11 mmol / L, and the concentration of cetyltrimethylammonium bromide is 8-15 mmol / L. The choline molecule has two functions, which can reduce chloroauric acid to prepare gold nanowires, and also can act as a catalyst to catalyze the hydrolysis / condensation of tetramethyl orthosilicate to form a mesoporous silica shell.
[0009] Further, in the reaction system, the concentration of chloroauric acid is 0.5-1.0 mmol / L, and the concentration of tetramethyl orthosilicate is 0.04-0.08 mol / L.
[0010] Further, the purification is specifically as follows: after the product obtained by the reaction is centrifuged and separated, water washing, drying at 100-140 DEG C for 6-12 hours, and then calcining at 500-600 DEG C for 4-6 hours to remove impurities such as CTAB.
[0011] In the preparation method of the present application, the order of adding the sample is preferably water, choline, cetyltrimethylammonium bromide, chloroauric acid, and finally tetramethyl orthosilicate.
[0012] A preferred preparation method of mesoporous silica coated gold composite nanowires is specifically as follows: in 50 mL of pure water, the temperature is controlled to be constant at 95-100 DEG C, 2 mL of choline solution with a mass fraction of 3.0%, 0.2 g of cetyltrimethylammonium bromide (CTAB), 2 mL of chloroauric acid solution with a concentration of 20.0 mM, and 0.5 mL of tetramethyl orthosilicate (TMOS) are sequentially added under stirring condition, the stirring and reaction are continuously carried out at a constant temperature of 95-100 DEG C for 3 hours, and after the reaction is completed, centrifugation, water washing, drying and calcining are carried out to obtain the product.
[0013] In the preparation method, choline is used as a catalyst for hydrolysis / condensation reaction of tetramethyl orthosilicate (TMOS) and a reducing agent for reduction reaction of chloroauric acid (HAuCl4), cetyltrimethylammonium bromide (CTAB) is used as a template agent for mesoporous and an inducing agent for one-dimensional growth of Au nanowires, TMOS is used as a silicon source, and HAuCl4 is used as a gold source, and then by adjusting the concentration of CTAB in the reaction medium and the usage amount of the silicon source and the gold source, the Au@mesoporous SiO2 composite nanowires with a diameter of about 70-95 nanometers and a length of about 0.5-2 micrometers can be prepared in one step.
[0014] Compared with the prior art, the preparation method has the following beneficial effects:
[0015] The method adopts a sol-gel chemical method, that is, the Au@mesoporous SiO2 composite nanowires with a diameter of about 70-95 nanometers and a length of about 0.5-2 micrometers can be prepared in one step in a one-pot reaction, and the yield is as high as 95%. In the reaction process, CTAB is an inducing agent for one-dimensional growth of gold nanowires and a pore-forming template agent for a mesoporous silica shell, and choline has a dual function of a catalyst and a reducing agent. Moreover, the preparation method of the Au@mesoporous SiO2 composite nanowires is simpler, has a good regulation effect, is more efficient, and has great popularization and application value. BRIEF DESCRIPTION OF DRAWINGS
[0016] Figure 1 A transmission electron microscope (TEM) image of the Au@mesoporous SiO2 composite nanowires obtained according to the embodiment of the present application;
[0017] Figure 2 An ultraviolet-visible absorption spectrum image of the Au@mesoporous SiO2 composite nanowires obtained according to the embodiment of the present application, and the inset is a digital photograph of an aqueous solution of the composite nanowires;
[0018] Figure 3 An N2 adsorption-desorption curve of the Au@mesoporous SiO2 composite nanowires obtained according to the embodiment of the present application;
[0019] Figure 4 A mesopore size distribution curve of the Au@mesoporous SiO2 composite nanowires obtained according to the embodiment of the present application. DETAILED DESCRIPTION
[0020] The technical solutions of the present application are further described in detail below in combination with the embodiments, but the protection scope of the present application is not limited thereto.
[0021] The environmental temperature is 25℃, and the atmospheric pressure is 1 atm;
[0022] Water: density 1.0 g / mL, molecular weight 18 g / mol;
[0023] Choline solution: a commercially available product with a mass fraction of 50%, diluted to 3.0% before use;
[0024] Cetyltrimethylammonium bromide (CTAB): a commercially available product with a molecular weight of 364.45 g / mol;
[0025] Chloroauric acid (HAuCl4): a commercially available product;
[0026] Tetramethyl orthosilicate (TMOS): a commercially available product with a density of 1.023 g / mL and a molecular weight of 152.22 g / mol.
[0027] Example 1
[0028] A preparation method of mesoporous silica-coated gold composite nanowires, which specifically comprises the following steps:
[0029] In 50 mL of pure water, the temperature was controlled to be constant at 100°C, then 2 mL of choline solution with a mass fraction of 3.0%, 0.2 g of CTAB, 2 mL of chloroauric acid solution with a concentration of 20.0 mM were added under stirring, and finally 0.5 mL of TMOS was added. The reaction was continued at a constant temperature of 100°C for 3 hours under stirring. After the reaction was completed, the reaction product was first centrifuged and washed with water twice, then dried at 120°C for 8h, and finally calcined at 550°C for 5 hours to remove impurities such as CTAB. Finally, the pure and crude Au@mesoporous SiO2 composite nanowires with a diameter of about 80 nm and a length of about 1 µm were obtained, with a yield of about 95%.
[0030] The TEM image of the product is shown in Figure 1 From Figure 1 it can be seen that the Au@mesoporous SiO2 composite nanowires have a diameter of about 80 nm and a length of about 1 µm, and the gold nanowires are completely coated inside the mesoporous silica.
[0031] The ultraviolet-visible absorption spectrum of the product is shown in Figure 2 From Figure 2 it can be clearly seen that the half-peak width of the Au plasmon resonance peak at 530 nm is very wide, and multiple absorption peaks appear, indicating that it has a clear linear structure. Figure 2 The inset in shows that its aqueous solution is purple black, also indicating that it has a linear structure.
[0032] Figure 3 The N2 adsorption-desorption curve of the product is shown in Figure 3 From o it can be seen that the particles exhibit a very obvious N2 adsorption-desorption hysteresis loop near 0.4 P / P o , indicating that they have a clear mesoporous structure, and the pore volume is about 0.48 cm3 / g, the BET specific surface area was about 843.40 m 2 / g.
[0033] The product mesopore size distribution curve is shown in Figure 4 , Figure 4 The data show that the particles have a very narrow mesopore distribution, with an average pore size of about 3.5 nm.
[0034] The above only describes the preferred embodiments of the present application, and it should be noted that for those skilled in the art, without departing from the principles of the present application, a number of improvements and refinements can be made, and these improvements and refinements should also be considered as the protection scope of the present application.
Claims
1. A method for preparing mesoporous silica-coated gold composite nanowires, characterized by, The water temperature is kept constant at 90-100℃, and choline solution, cetyltrimethylammonium bromide, chloroauric acid solution and tetramethyl silicate are added successively under stirring; then the reaction is stirred at 90-100℃ for 2.5-3.5 hours, and after the reaction is completed, centrifugation and purification are performed to obtain the product; In the reaction system, the concentration of choline is 9-11 mmol / L; the concentration of cetyltrimethylammonium bromide is 8-15 mmol / L; the concentration of chloroauric acid is 0.5-1.0 mmol / L; and the concentration of tetramethyl silicate is 0.04-0.08 mol / L. The purification is specifically as follows: the product obtained by reaction is centrifuged, washed with water, dried at 100-140℃ for 6-12 hours, and then calcined at 500-600℃ for 4-6 hours.
2. The method for preparing mesoporous silica-coated gold composite nanowires as described in claim 1, characterized in that, In 50 mL of pure water, the temperature is kept constant at 95-100℃, and 2 mL of choline solution with a mass fraction of 3.0%, 0.2 g of cetyltrimethylammonium bromide, 2 mL of chloroauric acid solution with a concentration of 20.0 mM and 0.5 mL of tetramethyl silicate are added successively under stirring; the reaction is stirred at a constant temperature of 95-100℃ for 3 hours, and after the reaction is completed, centrifugation, water washing, drying and calcination are performed to obtain the product.