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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.


XPS spectrum of AuNPs synthesized via CO gas reduction. The Au 4f7/2 peak appeared at a binding energy of 83.98 eV and the Au 4f5/2 peak appeared at a binding energy of 87.71 eV. This indicates the formation of metallic gold [27,28].
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Figure 3: XPS spectrum of AuNPs synthesized via CO gas reduction. The Au 4f7/2 peak appeared at a binding energy of 83.98 eV and the Au 4f5/2 peak appeared at a binding energy of 87.71 eV. This indicates the formation of metallic gold [27,28].

Mentions: Increasing the chloroauric acid concentration reduced the polydispersity of the nanoparticles, yet the gas-injection flow rate continued to influence the AuNP size distribution profiles. Figure 2 shows the UV-visible spectra of AuNPs synthesized from a chloroauric acid concentration of 0.03 mM at flow rates of 16.9, 25.5, and 37.0 mL/min (Figure 2A, B, C). The polydispersity of the AuNPs aerated at 16.9 mL/min (Figure 2A) is represented by a broad particle distribution curve. The particle sizes for Figure 2A ranged from 2.5 to 17 nm in diameter. Increasing the CO flow reduced the width of the particle distribution curve where an optimum inlet gas flow was obtained at 25.5 mL/min (Figure 2B). The standard deviation for 2B was 7%, well below the 13 to 15% normally obtained for comparable sizes via citrate reduction [3]. To confirm the formation of Au atoms from HAuCl4, the valence state of Au was identified by X-ray photoelectron spectroscopy (XPS). Figure 3 shows an XPS spectrum of AuNPs synthesized via CO gas reduction. The Au 4f7/2 peak appeared at a binding energy of 83.98 eV and the Au 4f5/2 peak appeared at a binding energy of 87.71 eV. This indicates the formation of metallic gold [27,28]. These particles remained stable in excess of 12 months when stored at 4°C.


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)

XPS spectrum of AuNPs synthesized via CO gas reduction. The Au 4f7/2 peak appeared at a binding energy of 83.98 eV and the Au 4f5/2 peak appeared at a binding energy of 87.71 eV. This indicates the formation of metallic gold [27,28].
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 3: XPS spectrum of AuNPs synthesized via CO gas reduction. The Au 4f7/2 peak appeared at a binding energy of 83.98 eV and the Au 4f5/2 peak appeared at a binding energy of 87.71 eV. This indicates the formation of metallic gold [27,28].
Mentions: Increasing the chloroauric acid concentration reduced the polydispersity of the nanoparticles, yet the gas-injection flow rate continued to influence the AuNP size distribution profiles. Figure 2 shows the UV-visible spectra of AuNPs synthesized from a chloroauric acid concentration of 0.03 mM at flow rates of 16.9, 25.5, and 37.0 mL/min (Figure 2A, B, C). The polydispersity of the AuNPs aerated at 16.9 mL/min (Figure 2A) is represented by a broad particle distribution curve. The particle sizes for Figure 2A ranged from 2.5 to 17 nm in diameter. Increasing the CO flow reduced the width of the particle distribution curve where an optimum inlet gas flow was obtained at 25.5 mL/min (Figure 2B). The standard deviation for 2B was 7%, well below the 13 to 15% normally obtained for comparable sizes via citrate reduction [3]. To confirm the formation of Au atoms from HAuCl4, the valence state of Au was identified by X-ray photoelectron spectroscopy (XPS). Figure 3 shows an XPS spectrum of AuNPs synthesized via CO gas reduction. The Au 4f7/2 peak appeared at a binding energy of 83.98 eV and the Au 4f5/2 peak appeared at a binding energy of 87.71 eV. This indicates the formation of metallic gold [27,28]. These particles remained stable in excess of 12 months when stored at 4°C.

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.