Background
Gold nanoparticles are an earlier-researched nano material, are widely applied in the fields of catalysis, photoelectron, biomedicine and the like at present, the properties of the gold nanoparticles are often related to the size and the shape of the gold nanoparticles, and various structures such as nanospheres, nanocubes, nano tetrahedrons, hexagons, nanodiscs, pyramid-shaped nanoparticles, nanorods, nanowires, nanocages, nanoshells, nanostars and the like are obtained by developing different synthetic methods. The properties of gold nanoparticles are influenced by their shape and size, and the structure of surface adsorbed molecules, for example, the surface raman effect is related to the size, shape and surface molecules of gold nanoparticles.
At present, few synthesis methods of gear-shaped gold nanoparticles are reported, the gear-shaped gold nanoparticles are of a complex nanoparticle structure, and AgNO needs to be introduced into the synthesis process of the complex gold nanoparticles3And the reagent is used for regulating and controlling the shape of the gold nanoparticles. However, AgNO3The addition amount of the gold nanoparticle has great influence on the shape of the final gold nanoparticle, and the gold nanoparticle with a regular shape is difficult to obtain repeatedly in practice; and the synthetic process has complex operation steps.
In view of the above, the invention provides a simple and rapid synthetic method of gear-shaped gold nanoparticles with easy control and high repeatability, which solves the above technical problems.
Disclosure of Invention
The invention aims to overcome the technical defects and provides a synthesis method of gear-shaped gold nanoparticles, which has the advantages of easily controlled conditions, simple steps, high repeatability, short reaction time and the like, and the obtained gear-shaped gold nanoparticles have regular shapes.
In order to solve the technical problems, the technical scheme of the invention is as follows:
a synthetic method of gear-shaped gold nanoparticles comprises the following steps:
step S1, preparing a seed solution: to 10mL of a 0.1M CTAC solution was added 0.25mL of 10mM HAuCl4Then 0.6mL of 0.1M frozen NaBH was added4Stirring for 1-5min to change the solution from light yellow to dark brown, and standing for 2h to prepare a seed solution;
step S2, diluting the seed solution to 1000 times by adopting a CTAC solution of 0.1M for later use;
step S3, synthesizing gear-shaped gold nanoparticles: 500uL of 10mM HAuCl4Adding into 10mL of 0.08-0.12M CTAC stock solution, and stirring uniformly; adding 60uL of 1M NaOH, mixing uniformly, adding 18-42uL of 0.98M H2O2And after the solution becomes colorless, adding 25-500uL of the seed solution diluent obtained in the step S2, standing at room temperature for 1h to grow, and preparing the gear-shaped gold nanoparticles.
Further, the average particle diameter of the gear-shaped gold nanoparticles is 43 to 127 nm.
Further, the particle size of the cogged gold nanoparticles increased with the decrease in the amount of seed solution added.
Furthermore, the number of gears on the surface of the gear-shaped gold nanoparticles is 2-9.
Further, the number of gears on the surface of the gear-shaped gold nanoparticles increases as the amount of the seed solution is reduced.
Further, in step S1, the solution mixing is performed by a magnetic stirrer, wherein the rotation speed of the magnetic stirrer is 800-.
Compared with the prior art, the synthesis method of the gear-shaped gold nanoparticles has the beneficial effects that:
the invention provides a synthesis method of gear-shaped gold nanoparticles, which uses H under alkaline conditions202As the reducing agent, the reaction principle is H under alkaline conditions2O2Reduction of Au+The reduction is carried out on the surface of the gold nano-particles, and the simple substance gold is deposited on the surface of the nano-particles after the reduction, so that the gold nano-seeds grow. Due to the fact that CTAC coats a specific crystal face (such as a (100) crystal face), deposition occurs at a specific position on the surface of the gold nano-seed, and therefore nano-particles with different sizes and gear numbers are formed. Compared with the prior art, the synthesis method of the gear-shaped gold nanoparticles provided by the invention uses H202The gold nanoparticles with different sizes and regular shapes are prepared by adjusting the addition amount of the seed solution under the alkaline condition as a reducing agent, and the method has the advantages of simple reaction condition and steps, short reaction time, convenient control and the like.
Detailed Description
In order to make the technical solutions in the embodiments of the present invention better understood and make the above objects, features, and advantages of the present invention more comprehensible, specific embodiments of the present invention are described below with reference to the accompanying drawings.
The endpoints of the ranges and any values disclosed herein are not limited to the precise range or value, and such ranges or values should be understood to encompass values close to those ranges or values. For ranges of values, between the endpoints of each of the ranges and the individual values, and between the individual values may be combined with each other to yield one or more new ranges of values, which ranges of values should be considered as specifically disclosed herein.
A synthetic method of gear-shaped gold nanoparticles comprises the following steps:
step S1, preparing a seed solution: to 10mL of a 0.1M CTAC solution was added 0.25mL of 10mM HAuCl4Then 0.6mL of 0.1M frozen NaBH was added4Stirring for 1-5min to change the solution from light yellow to dark brown, and standing for 2h to prepare a seed solution;
wherein the solution mixing is carried out under the action of a magnetic stirrer, and the rotating speed of the magnetic stirrer is 800-1200 rpm;
step S2, diluting the seed solution to 1000 times by adopting a CTAC solution of 0.1M for later use;
step S3, synthesizing gear-shaped gold nanoparticles: 500uL of 10mM HAuCl4Adding the mixture into 10mL of 0.08-0.12M CTAC stock solution, and uniformly stirring; adding 60uL of 1M NaOH, mixing uniformly, adding 18-42uL of 0.98M H2O2And after the solution becomes colorless, adding 25-500uL of the seed solution diluent obtained in the step S2, standing at room temperature for 1h to grow, and preparing the gear-shaped gold nanoparticles.
Example 1
A synthetic method of gear-shaped gold nanoparticles comprises the following steps:
step S1, preparing a seed solution: to 10mL of a 0.1M CTAC solution was added 0.25mL of 10mM HAuCl4Then 0.6mL of 0.1M frozen NaBH was added4Stirring for 1-5min to change the solution from light yellow to dark brown, and standing for 2h to prepare a seed solution;
wherein the solution mixing is carried out under the action of a magnetic stirrer, and the rotating speed of the magnetic stirrer is 1200 rpm;
step S2, diluting the seed solution to 1000 times by adopting a CTAC solution of 0.1M for later use;
step S3, synthesizing gear-shaped gold nanoparticles: 500uL of 10mM HAuCl4Adding the mixture into 10mL of 0.1M CTAC stock solution, and uniformly stirring; adding 60uL of 1M NaOH, mixing well, adding 30uL of 0.98M H2O2And after the solution becomes colorless, respectively adding 25 uL, 50 uL, 100 uL, 250 uL and 500uL of the seed solution diluent obtained in the step S2, standing at room temperature for 1h to grow, and preparing the gear-shaped gold nanoparticles with different sizes and tooth numbers.
Please refer to fig. 1 and fig. 2 in combination, wherein fig. 1 is a graph of the uv-vis absorption spectra of gold nanoparticles corresponding to different amounts of seed solutions in the present invention; FIG. 2 is TEM images of gold nanoparticles corresponding to different amounts of seed solutions in the present invention. In fig. 1, curves a, b, c, d, and e correspond to the uv-vis absorption spectra of the gold nanoparticles with the seed solution addition amounts of 25 uL, 50 uL, 100 uL, 250 uL, and 500uL, respectively. As can be seen from FIG. 1, as the amount of the seed solution is continuously decreased, the plasma resonance (LLSPR) of the gold nanoparticles is obviously red-shifted, and the wavelength of the maximum absorption peak is shifted from 570nm to 695 nm.
In FIG. 2, (a), (b), (c), (d), (e) correspond to TEM characterization images of the seed solutions added with 500uL, 250 uL, 100 uL, 50 uL, and 25 uL of gold nanoparticles, respectively. As can be seen from fig. 2, the gold nanoparticles are gear-shaped and have regular shapes; with the gradual reduction of the addition of the seed solution, the size of the prepared gear-shaped gold nanoparticles is larger and larger, the average particle size is increased from 43 +/-0.56 nm to 127 +/-3.56 nm, and the number of teeth on the surface of the gold nanoparticles is increased. Through detection of a transmission electron microscope, when the addition amounts of the seed solutions are respectively 25 uL, 50 uL, 100 uL, 250 uL and 500uL, the numbers of the gears on the surfaces of the synthesized gold nanoparticles with the concentration of 95% or more are respectively 7-9, 5-8, 4-6, 3-5 and 2-4, which indicates that the smaller the addition amount of the seed solution in a certain range, the larger the number of the gears on the surfaces of the gold nanoparticles.
It should be noted that, in the gear-shaped gold nanoparticle synthesis process, the molar concentration of the added CTAC stock solution may also be 0.08M, 0.09M, 0.11M, 0.12M, H2O2The addition amount of the gold nanoparticle can also be 18 uL, 20 uL, 25 uL, 35 uL, 40 uL, 42uL and other volume amounts, and the prepared gold nanoparticle is also in a gear shape with a regular shape.
The invention provides a synthesis method of gear-shaped gold nanoparticles, which uses H202The gold nanoparticles with different sizes and regular shapes are prepared by adjusting the addition amount of the seed solution under the alkaline condition as a reducing agent, and the method has the advantages of simple reaction condition and steps, short reaction time, convenient control and the like.
The embodiments of the present invention are described in detail above with reference to the drawings, but the present invention is not limited to the described embodiments. Various changes, modifications, substitutions and alterations to these embodiments will occur to those skilled in the art without departing from the spirit and scope of the present invention.