CN111283214B

CN111283214B - Pure silver nanorod with hexagonal cross section and preparation method thereof

Info

Publication number: CN111283214B
Application number: CN202010120665.1A
Authority: CN
Inventors: 杨鹏飞; 梁雨; 刘卫国; 张大霄
Original assignee: Xian Technological University
Current assignee: Xian Technological University
Priority date: 2020-02-26
Filing date: 2020-02-26
Publication date: 2022-08-05
Anticipated expiration: 2040-02-26
Also published as: CN111283214A

Abstract

The invention belongs to the technical field of nano-structure preparation, and particularly relates to a pure silver nanorod with a hexagonal cross section and a preparation method thereof. The preparation method adopted by the invention comprises the following steps: stirring 15-30 ml of sodium dodecyl sulfate aqueous solution for 10-30 min at 26-27 ℃, then rapidly and sequentially adding 0.4-0.8 ml of silver nitrate aqueous solution, 0.05-0.1 ml of ascorbic acid aqueous solution and 0.004-0.04 ml of silver nanoparticle dispersed aqueous solution, maintaining the stirring state for reaction for 3h, centrifuging to obtain lower-layer precipitate pure silver nanorods with hexagonal sections, and dispersing and storing the pure silver nanorods in the aqueous solution. The invention provides a pure silver nanorod with a hexagonal section and a preparation method thereof, wherein silver nanoparticles are used as seeds to prepare an undoped silver nanorod structure with a hexagonal cross section, the longitudinal length of the undoped silver nanorod structure is 50-500 nm, and the transverse diameter of the undoped silver nanorod structure is 20-10 nm.

Description

Pure silver nanorod with hexagonal cross section and preparation method thereof

Technical Field

The invention belongs to the technical field of nano-structure preparation, and particularly relates to a pure silver nanorod with a hexagonal cross section and a preparation method thereof.

Background

The shape and size of the noble metal nanostructure directly influence the physical and chemical properties of the noble metal nanostructure, so that the preparation method of the noble metal nanostructure with different shapes becomes a great concern in the related research field.

Silver nanorods have been favored by researchers in nano-optics because of their high quality factor as anisotropically grown noble metal structures. The preparation of silver nanorods usually selects a high-temperature alcohol reduction method or grows by means of metal nanoparticles as seed crystals.

The silver nano-rod prepared by the high-temperature alcohol reduction method has stable shape but poor size controllability, and is always accompanied with silver nano-particles and silver nano-wires with different sizes;

the method for preparing the silver nanorods by utilizing the seeds has high controllability, high yield and uniform size, but due to the instability of the silver nanoparticles, the silver nanoparticles cannot be subjected to good anisotropic differentiation in a culture solution, so that the nano bipyramid particles of other metals are usually selected as growth seed crystals of the silver nanorods, for example, Pd seeds provided by Younan Xia and the like and Au seeds provided by Jianfang Wang and the like, the yield and the quality of the silver nanorods are greatly improved, but impurity metals are introduced into the silver nanorods, and interference signals are brought to the research in nano optics to a certain extent.

Disclosure of Invention

In view of the above, the invention provides a pure silver nanorod with a hexagonal section and a preparation method thereof, and the pure silver nanorod with the hexagonal section and the undoped silver nanorod structure with the hexagonal cross section are stably prepared at high yield by taking silver nanoparticles as seeds, wherein the longitudinal length of the silver nanorod is 50-500 nm, and the transverse diameter of the silver nanorod is 20-100 nm.

In order to solve the problems in the prior art, the technical scheme of the invention is as follows: a preparation method of pure silver nanorods with hexagonal cross sections is characterized in that: stirring 15-30 ml of sodium dodecyl sulfate aqueous solution for 10-30 min at 26-27 ℃, then rapidly and sequentially adding 0.4-0.8 ml of silver nitrate aqueous solution, 0.05-0.1 ml of ascorbic acid aqueous solution and 0.004-0.04 ml of silver nanoparticle dispersed aqueous solution, reacting for 3h under a stirring state, centrifuging to obtain a lower-layer precipitate of pure silver nanorods with hexagonal sections, and dispersing and storing the pure silver nanorods in the aqueous solution.

Further, the concentration of the sodium dodecyl sulfate aqueous solution is 0.005 mol/L;

further, the concentration of the silver nitrate aqueous solution is 0.01 mol/L;

further, the concentration of the ascorbic acid aqueous solution is 0.1 mol/L;

further, the silver nano particles are silver nanospheres based on sodium alginate as a carrier; the diameter of the silver nanoparticles is 5-10 nm; the concentration of the dispersion solution was 8.696X 10 ^-4 mol/L；

The pure silver nanorod with the hexagonal cross section is prepared by the preparation method.

Compared with the prior art, the invention has the following advantages:

1) in the research of the nano-optics field, the prepared undoped pure silver nanorod greatly avoids the loss caused by other impurity metals, and well improves the defects caused by the silver nanorod which grows by taking materials such as gold and the like as seeds;

2) the silver nanorod with the hexagonal cross section prepared by the method is novel in shape, high in yield and uniform in size, is different from a silver nanorod with the pentagonal cross section prepared by the prior art, so that not only is the anisotropically-grown silver nanostructure innovated, but also a new application object is provided for the research of nano optics, and meanwhile, the stable and uniform yield brings great convenience for the research of nano optics;

3) the preparation method of the pure silver nanorod with the hexagonal cross section is non-toxic and environment-friendly, has mild growth environment, and is safer and more controllable compared with the existing high-temperature alcohol reduction method for preparing the pure silver nanorod;

4) the preparation method of the invention takes the silver nano-particles taking sodium alginate as the carrier as the silver seed crystal to prepare the silver nano-structure, which is an unprecedented attempt, so sodium dodecyl sulfate which can be highly self-organized with sodium alginate is selected as a surfactant in the growth environment to induce the further differentiation growth of the silver seed crystal, thereby obtaining the novel pure silver nano-rod.

Description of the drawings:

FIG. 1 is a scanning electron microscope and a transmission electron microscope of a pure silver nanorod with a hexagonal cross section as described in example 1 of the present invention;

FIG. 2 is an energy scattering spectrum of a pure silver nanorod with a hexagonal cross section as described in example 1 of the present invention;

FIG. 3 is a scanning electron microscope image of the silver nano bulk structure described in example 2 of the present invention.

FIG. 4 scanning electron micrographs of the asymmetric candle-like silver nanostructures described in example 3 of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

The pure silver nanorod with the hexagonal cross section is an undoped silver nanorod prepared by taking silver nanoparticles as growth seeds; the hexagonal section means that the cross section of the silver nanorod growing anisotropically is hexagonal; the silver nanorod shape comprises a symmetrical rod-shaped structure or an asymmetrical candle-shaped structure; the silver nanorods have a longitudinal length of 50-500 nm and a transverse diameter of 20-100 nm.

Example 1

A preparation method of pure silver nanorods with hexagonal cross sections comprises the following steps:

1. firstly, preparing silver nanoparticles with sodium alginate as a carrier:

under the condition of room temperature, adding 50ml of silver nitrate aqueous solution with the concentration of 0.01mol/L into 500g of sodium alginate aqueous solution with the mass fraction of 0.01%, stirring for 30 minutes in a dark place, injecting 25ml of sodium borohydride aqueous solution with the concentration of 0.1mol/L, reacting for one hour, naturally dialyzing in deionized water for 3-5 days by using a dialysis bag to obtain silver nanoparticles with the sodium alginate as a carrier, wherein the concentration of the silver nanoparticle dispersion solution is 8.696 multiplied by 10 ^-4 mol/L。

2. Preparing pure silver nanorods:

stirring 15ml of 0.005mol/L sodium dodecyl sulfate aqueous solution for 30min at 26-27 ℃, and then rapidly and sequentially adding 0.4ml of 0.01mol/L silver nitrate aqueous solution, 0.05ml of 0.1mol/L ascorbic acid aqueous solution and 0.004ml of 8.696 multiplied by 10 aqueous solution ^-4 And (3) after the silver nano-particle dispersion aqueous solution of mol/L reacts for 3 hours in a stirring state, centrifuging at a rotating speed of 5500 revolutions per minute for 15-20 min, removing the supernatant, adding an equal-volume aqueous solution, keeping the same rotating speed and time for carrying out second centrifugation, removing the supernatant again, obtaining a lower-layer precipitate as a reaction product, and adding a certain amount of aqueous solution to disperse and store the reaction product.

The reaction product of the embodiment is a pure silver nanorod structure with a hexagonal cross section, and mainly comprises a symmetrical nanorod structure accompanied by a small amount of asymmetrical candle-shaped structures, the longitudinal length of the silver nanorod is 200-400 nm, the transverse diameter of the silver nanorod is 30-50 nm, the appearance scanning electron microscope and the transmission electron microscope are shown in fig. 1, and the hexagonal cross section of the pure silver nanorod is shown in fig. 1. The energy scattering spectrum of the pure silver nanorod with the hexagonal cross section is shown in fig. 2, wherein the energy spectrum peak of copper is generated by a special grid for collecting the energy spectrum.

Example 2

1. Firstly, preparing silver nanoparticles with sodium alginate as a carrier:

silver nanoparticles with sodium alginate as carrier were prepared by the same method steps as in example 1.

2. Preparing pure silver nanorods:

stirring 20ml of a 0.005mol/L sodium dodecyl sulfate aqueous solution for 30min at the temperature of 26-27 ℃, rapidly and sequentially adding 0.5ml of a 0.01mol/L silver nitrate aqueous solution, 0.07ml of a 0.1mol/L ascorbic acid aqueous solution and 0.04ml of a 8.696 x 10 < -4 > mol/L silver nanoparticle dispersion aqueous solution, maintaining the stirring state for reaction for 3h, centrifuging at the rotating speed of 5500 rpm for 15-20 min, removing the supernatant, adding an isovolumetric aqueous solution, keeping the same rotating speed and time for carrying out secondary centrifugation, removing the supernatant again, obtaining a lower-layer precipitate as a reaction product, and adding a certain amount of aqueous solution to disperse and store the reaction product.

The reaction product of the embodiment is a silver nano short rod-shaped structure containing a hexagon, the longitudinal length is 50-200 nm, the transverse diameter is 30-50 nm, and a shape scanning electron microscope image is shown in fig. 3, and is accompanied by a plurality of silver nano blocky structures with unobvious anisotropic growth.

Example 3

1. Firstly, preparing silver nanoparticles with sodium alginate as a carrier:

2. Preparing pure silver nanorods:

stirring 30ml of a 0.005mol/L sodium dodecyl sulfate aqueous solution for 30min at the temperature of 26-27 ℃, then rapidly and sequentially adding 0.8ml of a 0.01mol/L silver nitrate aqueous solution and 0.1ml of a 0.1mol/L ascorbic acid aqueous solution for reacting for 3-5 min, then adding 0.04ml of a 8.696 x 10 < -4 > mol/L silver nanoparticle dispersed aqueous solution, maintaining the stirring state for reacting for 3h, then centrifuging at a rotating speed of 5500 rpm for 15-20 min, removing supernatant, adding an isometric aqueous solution, keeping the same rotating speed and time for centrifuging for the second time, removing the supernatant again, obtaining a reaction product as a lower-layer precipitate, and adding a certain amount of aqueous solution for dispersing and storing.

The reaction product of the embodiment is a pure silver nanorod with a hexagonal cross section, the longitudinal length is 50-500 nm, the transverse diameter is 30-100 nm, and a shape scanning electron microscope image is shown in fig. 4, wherein asymmetric candle-shaped silver nanostructures are increased, end parts with smaller diameters are obviously differentiated, and more byproduct particles are accompanied.

The above description is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention, and it should be noted that those skilled in the art should make modifications and variations without departing from the principle of the present invention.

Claims

1. A preparation method of pure silver nanorods with hexagonal cross sections is characterized in that: stirring 15-30 ml of sodium dodecyl sulfate aqueous solution for 10-30 min at 26-27 ℃, rapidly and sequentially adding 0.4-0.8 ml of silver nitrate aqueous solution, 0.05-0.1 ml of ascorbic acid aqueous solution and 0.004-0.04 ml of silver nanoparticle dispersed aqueous solution, reacting for 3h under a stirring state, centrifuging to obtain lower-layer precipitate pure silver nanorods with hexagonal sections, and dispersing and storing the pure silver nanorods in the aqueous solution;

the silver nano particles are silver nanospheres based on sodium alginate as a carrier.

2. The method for preparing pure silver nanorods with hexagonal cross section according to claim 1, characterized in that: the concentration of the sodium dodecyl sulfate aqueous solution is 0.005 mol/L.

3. The method for preparing pure silver nanorods with hexagonal cross section according to claim 1 or 2, characterized in that: the concentration of the silver nitrate aqueous solution is 0.01 mol/L.

4. The method for preparing pure silver nanorods with hexagonal cross section according to claim 3, characterized in that: the concentration of the ascorbic acid aqueous solution is 0.1 mol/L.

5. The method for preparing pure silver nanorods with hexagonal cross section according to claim 4, characterized in that: the diameter of the silver nano-particles is 5-10 nm; the concentration of the dispersed aqueous solution is 8.696X 10 ^-4 mol/L。

6. The preparation method of claim 1, wherein the pure silver nanorods with hexagonal cross section are prepared.