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

Young JK, Lewinski NA, Langsner RJ, Kennedy LC, Satyanarayan A, Nammalvar V, Lin AY, Drezek RA - Nanoscale Res Lett (2011)

Bottom Line: It is also found that speciation of aqueous HAuCl4, prior to reduction, influences the size, morphology, and properties of AuNPs when reduced with CO gas.Ensemble extinction spectra and TEM images provide clear evidence that CO reduction offers a high level of monodispersity with standard deviations as low as 3%.Upon synthesis, no excess reducing agent remains in solution eliminating the need for purification.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Electrical and Computer Engineering, Rice University, MS-366, 6100 Main St,, Houston, TX 77005, USA. drezek@rice.edu.

ABSTRACT
An in depth analysis of gold nanoparticle (AuNP) synthesis and size tuning, utilizing carbon monoxide (CO) gas as a reducing agent, is presented for the first time. The sizes of the AuNPs are tunable from ~4 to 100 nm by altering the concentration of HAuCl4 and inlet CO gas-injection flow rate. It is also found that speciation of aqueous HAuCl4, prior to reduction, influences the size, morphology, and properties of AuNPs when reduced with CO gas. Ensemble extinction spectra and TEM images provide clear evidence that CO reduction offers a high level of monodispersity with standard deviations as low as 3%. Upon synthesis, no excess reducing agent remains in solution eliminating the need for purification. The time necessary to synthesize AuNPs, using CO, is less than 2 min.

No MeSH data available.


Effect of increasing chloroauric acid concentrations on nanoparticle spectral profile. UV-visible spectra of gold nanoparticles with increasing chloroauric acid concentrations from 0.02 to 0.05 mM in 0.01 mM increments, from 0.1 to 0.5 mM in .1 mM increments, and at 1 mM. The inset is the absorbance spectra of gold nanoparticles produced from concentrations of 0.02 to 0.1 mM.
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Figure 4: Effect of increasing chloroauric acid concentrations on nanoparticle spectral profile. UV-visible spectra of gold nanoparticles with increasing chloroauric acid concentrations from 0.02 to 0.05 mM in 0.01 mM increments, from 0.1 to 0.5 mM in .1 mM increments, and at 1 mM. The inset is the absorbance spectra of gold nanoparticles produced from concentrations of 0.02 to 0.1 mM.

Mentions: As the concentration increased to 0.5 mM, 20 to 25 nm particles were produced. Continual increase of the chloroauric acid concentration beyond 0.5 to 0.6 mM only produced small changes in nanoparticle size with increased absorbance. The standard deviation for the AuNPs produced at 0.6 mM was 8% indicating monodispersity. As the concentration was increased to 1 mM, nanoparticles approaching 30 nm in diameter were produced but the standard deviation approached 20%. Further doubling the concentration to 2 mM had no uniform effect on particle growth, with the majority of the particles in the 30 nm size regime and some of the particles in the 40 to 55 nm size regime with a standard deviation approaching 35%. The UV-visible spectra of the sol prepared at different concentrations (Figure 4), increasing from 0.02 to 1 mM, shows an increase in absorbance which correlates to an increase in particle concentration and volume. Figure 5 shows the pronounced red shifting of the plasmon, which is associated with increased nanoparticle size. The red shift of the plasmon is further illustrated (see Additional file 3). This shifting effect is in line with the prediction described by Mie theory [1,2]. The statistical analysis of the particles synthesized from aqueous solutions of HAuCl4 ranging from 0.02 to 0.6 mM revealed an average standard deviation of approximately 11%.


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

Young JK, Lewinski NA, Langsner RJ, Kennedy LC, Satyanarayan A, Nammalvar V, Lin AY, Drezek RA - Nanoscale Res Lett (2011)

Effect of increasing chloroauric acid concentrations on nanoparticle spectral profile. UV-visible spectra of gold nanoparticles with increasing chloroauric acid concentrations from 0.02 to 0.05 mM in 0.01 mM increments, from 0.1 to 0.5 mM in .1 mM increments, and at 1 mM. The inset is the absorbance spectra of gold nanoparticles produced from concentrations of 0.02 to 0.1 mM.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
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getmorefigures.php?uid=PMC3211845&req=5

Figure 4: Effect of increasing chloroauric acid concentrations on nanoparticle spectral profile. UV-visible spectra of gold nanoparticles with increasing chloroauric acid concentrations from 0.02 to 0.05 mM in 0.01 mM increments, from 0.1 to 0.5 mM in .1 mM increments, and at 1 mM. The inset is the absorbance spectra of gold nanoparticles produced from concentrations of 0.02 to 0.1 mM.
Mentions: As the concentration increased to 0.5 mM, 20 to 25 nm particles were produced. Continual increase of the chloroauric acid concentration beyond 0.5 to 0.6 mM only produced small changes in nanoparticle size with increased absorbance. The standard deviation for the AuNPs produced at 0.6 mM was 8% indicating monodispersity. As the concentration was increased to 1 mM, nanoparticles approaching 30 nm in diameter were produced but the standard deviation approached 20%. Further doubling the concentration to 2 mM had no uniform effect on particle growth, with the majority of the particles in the 30 nm size regime and some of the particles in the 40 to 55 nm size regime with a standard deviation approaching 35%. The UV-visible spectra of the sol prepared at different concentrations (Figure 4), increasing from 0.02 to 1 mM, shows an increase in absorbance which correlates to an increase in particle concentration and volume. Figure 5 shows the pronounced red shifting of the plasmon, which is associated with increased nanoparticle size. The red shift of the plasmon is further illustrated (see Additional file 3). This shifting effect is in line with the prediction described by Mie theory [1,2]. The statistical analysis of the particles synthesized from aqueous solutions of HAuCl4 ranging from 0.02 to 0.6 mM revealed an average standard deviation of approximately 11%.

Bottom Line: It is also found that speciation of aqueous HAuCl4, prior to reduction, influences the size, morphology, and properties of AuNPs when reduced with CO gas.Ensemble extinction spectra and TEM images provide clear evidence that CO reduction offers a high level of monodispersity with standard deviations as low as 3%.Upon synthesis, no excess reducing agent remains in solution eliminating the need for purification.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Electrical and Computer Engineering, Rice University, MS-366, 6100 Main St,, Houston, TX 77005, USA. drezek@rice.edu.

ABSTRACT
An in depth analysis of gold nanoparticle (AuNP) synthesis and size tuning, utilizing carbon monoxide (CO) gas as a reducing agent, is presented for the first time. The sizes of the AuNPs are tunable from ~4 to 100 nm by altering the concentration of HAuCl4 and inlet CO gas-injection flow rate. It is also found that speciation of aqueous HAuCl4, prior to reduction, influences the size, morphology, and properties of AuNPs when reduced with CO gas. Ensemble extinction spectra and TEM images provide clear evidence that CO reduction offers a high level of monodispersity with standard deviations as low as 3%. Upon synthesis, no excess reducing agent remains in solution eliminating the need for purification. The time necessary to synthesize AuNPs, using CO, is less than 2 min.

No MeSH data available.