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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 CO flow rate on nanoparticle morphology. UV-visible extinction spectra of nanoparticles synthesized from a chloroauric acid concentration of 0.01 mM aerated at flow rates of 16.9, 25.5, 37.0, and 42.9 mL/min corresponding to A, B, C, and D, respectively, with accompanying TEM micrographs. A smoother, more pronounced spectrum was generated at the minimum flow rate of 16.9 mL/min when compared to the other injection flow rates. As the flow rate was increased from 16.9 to 42.9 mL/min the change in spectral symmetry was clearly visible.
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Figure 1: Effect of CO flow rate on nanoparticle morphology. UV-visible extinction spectra of nanoparticles synthesized from a chloroauric acid concentration of 0.01 mM aerated at flow rates of 16.9, 25.5, 37.0, and 42.9 mL/min corresponding to A, B, C, and D, respectively, with accompanying TEM micrographs. A smoother, more pronounced spectrum was generated at the minimum flow rate of 16.9 mL/min when compared to the other injection flow rates. As the flow rate was increased from 16.9 to 42.9 mL/min the change in spectral symmetry was clearly visible.

Mentions: To illustrate the effects of CO gas flow injection rates on nanoparticle synthesis, nanoparticles were synthesized from an aqueous solution of HAuCl4 acid at a concentration of 0.01 mM. Even at this lower concentration, which is normally not used for the synthesis of AuNPs, the extinction spectra is clearly visible and well formed as evident in Figure 1. A smoother, more pronounced spectrum was generated at the minimum flow rate of 16.9 mL/min when compared to the other injection flow rates. As the flow rate was increased from 16.9 to 42.9 mL/min the change in spectral symmetry was clearly visible. TEM micrographs of the corresponding nanoparticles are displayed in Figure 1. The gas-injection flow rate of 16.9 mL/min produced individual nanoparticles compared to the other injection rates. The nanoparticles produced by the 16.9 mL/min flow rate ranged in size from 5 to 11 nm in diameter. A flow rate of 25.45 mL/min, Figure 1B, produced nanoparticle aggregates and irregularly shaped particulate matter. Nanoparticles synthesized at a flow rate of 31.59 mL/min consisted of aggregated particle chains. A CO flow rate of 37 mL/min (Figure 1C) resulted in aggregated particle chains similar to that of nanoparticles produced at a flow rate of 25.45 mL/min. The particle aggregation in Figure 1B, D was evident by the broad spectral band. As the flow rate increased to 42.9 mL/min, the nanoparticles became elliptical in shape and very polydispersed. The nanoparticle sizes, when aerated at 42.9 mL/min, ranged from 5 to 40 nm in diameter with some aggregated particles; this size distribution is reflected in the broad spectral band.


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 CO flow rate on nanoparticle morphology. UV-visible extinction spectra of nanoparticles synthesized from a chloroauric acid concentration of 0.01 mM aerated at flow rates of 16.9, 25.5, 37.0, and 42.9 mL/min corresponding to A, B, C, and D, respectively, with accompanying TEM micrographs. A smoother, more pronounced spectrum was generated at the minimum flow rate of 16.9 mL/min when compared to the other injection flow rates. As the flow rate was increased from 16.9 to 42.9 mL/min the change in spectral symmetry was clearly visible.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211845&req=5

Figure 1: Effect of CO flow rate on nanoparticle morphology. UV-visible extinction spectra of nanoparticles synthesized from a chloroauric acid concentration of 0.01 mM aerated at flow rates of 16.9, 25.5, 37.0, and 42.9 mL/min corresponding to A, B, C, and D, respectively, with accompanying TEM micrographs. A smoother, more pronounced spectrum was generated at the minimum flow rate of 16.9 mL/min when compared to the other injection flow rates. As the flow rate was increased from 16.9 to 42.9 mL/min the change in spectral symmetry was clearly visible.
Mentions: To illustrate the effects of CO gas flow injection rates on nanoparticle synthesis, nanoparticles were synthesized from an aqueous solution of HAuCl4 acid at a concentration of 0.01 mM. Even at this lower concentration, which is normally not used for the synthesis of AuNPs, the extinction spectra is clearly visible and well formed as evident in Figure 1. A smoother, more pronounced spectrum was generated at the minimum flow rate of 16.9 mL/min when compared to the other injection flow rates. As the flow rate was increased from 16.9 to 42.9 mL/min the change in spectral symmetry was clearly visible. TEM micrographs of the corresponding nanoparticles are displayed in Figure 1. The gas-injection flow rate of 16.9 mL/min produced individual nanoparticles compared to the other injection rates. The nanoparticles produced by the 16.9 mL/min flow rate ranged in size from 5 to 11 nm in diameter. A flow rate of 25.45 mL/min, Figure 1B, produced nanoparticle aggregates and irregularly shaped particulate matter. Nanoparticles synthesized at a flow rate of 31.59 mL/min consisted of aggregated particle chains. A CO flow rate of 37 mL/min (Figure 1C) resulted in aggregated particle chains similar to that of nanoparticles produced at a flow rate of 25.45 mL/min. The particle aggregation in Figure 1B, D was evident by the broad spectral band. As the flow rate increased to 42.9 mL/min, the nanoparticles became elliptical in shape and very polydispersed. The nanoparticle sizes, when aerated at 42.9 mL/min, ranged from 5 to 40 nm in diameter with some aggregated particles; this size distribution is reflected in the broad spectral band.

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.