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

Joseph K Young1, Nastassja A Lewinski2, Robert J Langsner2, Laura C Kennedy2, Arthi Satyanarayan3, Vengadesan Nammalvar2, Adam Y Lin2 and Rebekah A Drezek12*

  • * Corresponding author: Rebekah A Drezek drezek@rice.edu

  • † Equal contributors

1 Department of Electrical and Computer Engineering, Rice University, MS-366, 6100 Main St., Houston, TX 77005, USA

2 Department of Bioengineering, Rice University, MS-142, 6100 Main St., Houston, TX 77005, USA

3 Department of Biochemistry and Cell Biology, Rice University, MS-140, 6100 Main St., Houston, TX 77005, USA

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Nanoscale Research Letters 2011, 6:428  doi:10.1186/1556-276X-6-428

Published: 16 June 2011

Additional files

Additional file 1:

Thermodynamics of HAuCl4 reduction in aqueous solutions using carbon monoxide as a reducing agent. The entire process is performed between 20 and 22°C and a pressure of 1 atm. The pH of the solution varies as a function of HAuCl4 concentration. Nernst equation describes potential of electrochemical cell as a function of concentrations of ions taking part in the reaction:

(1a)

where E0 is the standard reduction potential, R is the absolute gas constant = 8.31441 J/(mol K), F is Faraday constant = 96484.6 C/mol, T is the absolute temperature = 295.15 K, n is number or electrons, and Q is the reaction quotient. RT/F can be considered constant.

(2a)

(3a)

The CO gas is injected at a flow rate of 25.45 mL/min in 40 mL aqueous sample volumes. A water saturation constant of 0.26 g per 1 kg at 22°C is used.

(4a)

(5a)

(6a)

(7a)

(8a)

(9a)

Redox potentials (7) and (8) are given at pH 0. The redox potentials are pH-dependent and must be adjusted for the varying pH values.

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Additional file 2:

Effect of CO flow rate on nanoparticle spectral profile. Normalized UV-visible spectra of nanoparticles synthesized from a chloroauric acid concentration of 0.03 mM aerated at flow rates of 16.9, 25.5, and 37.0 mL/min corresponding to A, B, and C, respectively. The effect of the gas flow rate during synthesis is illustrated by a comparison of the three spectra.

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Additional file 3:

Plasmon peak position and absorbance value as a function of chloroauric acid concentration. The chloroauric acid concentration ranging from 0.01 to 1 mM. The data is plotted on a logarithmic scale. As the HAuCl4 concentration increases the absorbance intensity increases with an accompanying red-shift of the plasmon peak position.

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Additional file 4:

pH values before and after AuNP synthesis. pH values for given HAuCl4 concentrations ranging from 0.02 to 0.1 mM in 0.01 mM increments and from 0.1 to 0.5 mM in 0.1 mM increments. The x-axis is plotted on a logarithmic scale. The inset shows the pH values of the AuNP solutions from 0.01 to 0.1 mM and is plotted on a linear scale. As the reduction of HAuCl4 by CO takes place, H+ ions are liberated decreasing the pH of the solution. All pH measurements were taken at room temperature.

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