Shape-Controlled Synthesis of Gold and Silver Nanoparticles
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H. Bönnemann J. Hormes U. Kreibig in Handbook of Surface and Interfaces of Materials H. S. Nalwa Ed. (Academic Press San Diego CA 2001) pp. 1–87.
In a typical synthesis of silver nanocubes 5 ml of anhydrous ethylene glycol (Aldrich 99.8%) was heated at 160°C for 1 hour. 3 ml of ethylene glycol solution of AgNO 3 (0.25 M Aldrich 99+%) and 3 ml of ethylene glycol solution of PVP (0.375 M in repeating unit weight-average molecular weight ≈ 55 000 Aldrich) were simultaneously added to the ethylene glycol by means of a two-channel syringe pump at a rate of 0.375 ml/min. The reaction mixture was then continued with heating at 160°C for another 45 min. The product was dominated by cubic nanoparticles with a small amount (<5%) of silver nanowires. These nanowires could easily be separated from nanocubes through filtration because of their large difference in dimension. In this case the reaction mixture was diluted with water (25 times by volume) and filtered through Nucleopore membranes (Whatman Clifton NJ) that contained pores 1 μm in diameter. The silver nanocubes could be recovered from ethylene glycol through centrifugation and then redispersed into water.
B. D. Cullity S. R. Stock Elements of X – Ray Diffraction (Prentice-Hall Upper Saddle River NJ ed. 3 2001) pp. 402–404.
In a typical procedure for the preparation of gold nanoboxes a 5-ml aliquot of the aqueous dispersion containing silver nanocubes was refluxed for 10 min. Aliquots of 1 mM HAuCl 4 (99.9% Aldrich) aqueous solution were added dropwise to the refluxing solution. This mixture was continuously refluxed until its color became stable. Vigorous magnetic stirring was maintained throughout the synthesis.
Supported in part by the Office of Naval Research (grant N-00014-01-1-0976) a Career Award from NSF (grant DMR-9983893) and a research fellowship from the David and Lucile Packard Foundation. Y.X. is a Camille Dreyfus Teacher Scholar (2002–2007) and an Alfred P. Sloan Research Fellow (2000–2002). We thank D. Qin of the Nanotech User Facility for SEM analysis and X. Jiang Y. Yin Y. Lu B. Mayers and T. Herricks for their help with electron and x-ray diffraction studies.