Size-controlled synthesis of monodispersed gold nanoparticles via carbon monoxide gas reduction

Abstract

A method for forming monodispersed gold particles that includes preparing a solution of gold ions at a specific concentration and pH. Then, while stirring, dispersing CO gas into the solution. The gold ions in the solution are reduced by the CO reducing agent to form desired monodispersed gold particles. The reaction conditions are selected such that the growth period of the monodispersed gold particles is greater than a nucleation period of the gold ions.

What is claimed is: 
     
         1 . A method for forming solid monodispersed gold particles, comprising:
 preparing a solution of gold ions;   dispersing CO gas into the solution; and   reducing, using the CO gas, the gold ions to form the monodispersed solid gold particles,   wherein a growth period of the monodispersed solid gold particles is greater than a nucleation period of the gold ions.   
     
     
         2 . The method of  claim 1 , wherein the average diameter of the monodispersed solid gold particles ranges from 4 nm to 52 nm. 
     
     
         3 . The method of  claim 2 , wherein the CO gas is dispersed using a diffuser. 
     
     
         4 . The method of  claim 3 , wherein the diffuser has an average pore size of 60-μm. 
     
     
         5 . The method of  claim 1 , wherein the CO gas is dispersed in the solution of gold ions at a flow rate of at least 16 mL/min. 
     
     
         6 . The method of  claim 1 , wherein the CO gas is dispersed in the solution of gold ions at a flow rate of at least 42 mL/min. 
     
     
         7 . The method of  claim 1 , wherein the gold ions solution is a chloroauric acid solution 
     
     
         8 . The method of  claim 1 , wherein a concentration of gold ions in the solution of gold ions is between 0.01mM and 1 mM. 
     
     
         9 . The method of  claim 1 , wherein the solution of gold ions is stirred using a stir bar rotating at an RPM of at least 75. 
     
     
         10 . The method of  claim 1 , wherein the polydispersity of the monodispersed gold particles is less than 13%. 
     
     
         11 . A method forming monodispersed solid gold particles comprising:
 preparing a solution of gold ions with a specific pH;   dispersing CO gas into the solution; and   reducing, using the CO gas, the gold ions to form the monodispersed solid gold particles,   wherein a growth period of the monodispersed solid gold particles is greater than a nucleation period of the gold ions.   
     
     
         12 . The method of  claim 11 , wherein the specific pH of the solution of gold ions is set by the addition of potassium carbonate. 
     
     
         13 . The method of  claim 11 , wherein the CO gas is dispersed using a diffuser with an average pore size of 60-μm. 
     
     
         14 . The method of  claim 11 , wherein the CO gas is dispersed in the solution of gold ions at a flow rate of at least 16 mL/min. 
     
     
         15 . The method of  claim 11 , wherein the CO gas is dispersed in the solution of gold ions at a flow rate of at least 42 mL/min. 
     
     
         16 . The method of  claim 11 , wherein the gold ions solution is a chloroauric acid solution 
     
     
         17 . The method of  claim 11 , wherein the concentration of gold ions in the solution of gold ions is between 0.01mM and 1 mM. 
     
     
         18 . The method of  claim 11 , wherein the solution of gold ions is stirred using a stir bar rotating at an RPM of at least 75. 
     
     
         19 . The method of  claim 11 , wherein the polydispersity of the monodispersed solid gold particles is less than 13%. 
     
     
         20 . The method of  claim 11 , wherein the solution of gold ions is aged for at least 72 hrs prior to the dispersing of the CO gas.