Method for preparing size-controllable silver nanoparticles

A technology of silver nanoparticles and particle size, applied in nanotechnology and other directions, can solve the problems of wide size distribution range and difficult to control the size of silver nanoparticles, and achieve the effect of controllable preparation

Inactive Publication Date: 2014-02-26
TSINGHUA UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

At present, it is difficult to control the size of silver nanoparticles by most of the processing methods, and the obtained nanoparticles often have a wide range of size distribution.

Method used

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  • Method for preparing size-controllable silver nanoparticles
  • Method for preparing size-controllable silver nanoparticles
  • Method for preparing size-controllable silver nanoparticles

Examples

Experimental program
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Effect test

preparation example Construction

[0044] The preparation method of silver ammonia solution used is all as follows:

[0045] Configured to take 50mg AgNO 3 Add water to 10mL to obtain a silver nitrate aqueous solution with a concentration of 5mg / mL; add 100μL of a 1M NaOH aqueous solution (the molar ratio of silver nitrate to sodium hydroxide is 3:1) to form a brown precipitate, and then add 5% silver nitrate drop by volume Ammonia water, so that the formed AgOH brown precipitate just disappears, that is, a silver ammonia solution is formed; then the solution is diluted to AgNO 3 The concentration is 1mg / mL, obtained by filtering twice with a filter membrane with a pore size of 450nm, and set aside.

Embodiment 1

[0047] Dissolve 100mg of weak reducing agent glucose with aldehyde groups and 200mg of protective agent PVP in 150mL of deionized water, ultrasonically dissolve them completely, and filter twice through a filter membrane with a pore size of 450nm. After the pH value of the system was 9, 200 μL of gold seeds with a particle size of 5 nm were added (the concentration of gold seeds was 65 μg / mL), and then 2.5 mL of silver ammonia solution was added at a rate of 0.5 mL / min. The silver-ammonia reaction of the gold seed is completed after 5 minutes, and the sol containing the silver nanoparticles provided by the present invention is obtained.

[0048] The TEM photograph of the silver nanoparticles is as figure 1 As shown, it can be seen from the figure that the particle size of the silver nanoparticles is 24nm.

Embodiment 2

[0050]According to the same steps as in Example 1, only the reaction time of the silver-ammonia reaction step of the gold seed is replaced by 10, 40, 60, 100 and 120 minutes to obtain successively the following: figure 2 Silver nanoparticles with particle sizes of 50 nm, 70 nm, 90 nm, 105 nm and 120 nm are shown in B-F.

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Abstract

The invention discloses a method for preparing size-controllable silver nanoparticles. The method includes steps of adding sodium hydroxide or potassium hydroxide aqueous solution into mixed liquor comprising protective agents, water and weak reducing agents containing aldehyde groups and regulating a pH (potential of hydrogen) value of the mixed liquor until the pH value of the mixed liquor ranges from 8 to 10; adding Au seed crystal aqueous solution into the mixed liquor; then dripping silver and ammonia solution into the mixed liquor to carry out silver and ammonia reaction on the basis of gold seed crystals; acquiring sol containing the silver nanoparticles after reaction is completed. The method has the advantage that continuous growth of the Ag nanoparticles is controlled by a seed crystal growth process, so that the Ag nanoparticles with narrow size distribution (with relative standard deviation smaller than 20%) and the particle sizes which are continuously controllable within the range from 20nm to 120nm can be acquired.

Description

technical field [0001] The invention relates to a preparation method of size-controllable silver nanoparticles. Background technique [0002] Silver nanoparticles are usually prepared by chemical reduction of silver salts. Compared with gold salts, silver ions are more easily reduced, so it is difficult to control the size and consistency of Ag nanoparticles. The current conventional preparation method of silver nanoparticles is to use silver nitrate as the source of silver ions, use polymers (PVP, PVA, PEG, etc.) or molecules containing mercapto and amino groups as protective agents, and use reduction Agents (sodium borohydride, hydrazine hydrate, trisodium citrate, etc.) or radiation for the reduction of silver ions. At present, it is difficult to control the size of silver nanoparticles by most of the processing methods, and the obtained nanoparticles often have a wide range of size distribution. Contents of the invention [0003] The purpose of the present invention ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B22F9/24B82Y40/00
Inventor 宗瑞隆朱永法王小龙
Owner TSINGHUA UNIV
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