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Hydrothermal Syntheses of Gold Nanocrystals: From Icosahedral to Its Truncated Form
Author(s) -
Xu J.,
Li S.,
Weng J.,
Wang X.,
Zhou Z.,
Yang K.,
Liu M.,
Chen X.,
Cui Q.,
Cao M.,
Zhang Q.
Publication year - 2008
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.200700123
Subject(s) - ostwald ripening , nanocrystal , materials science , icosahedral symmetry , hydrothermal circulation , ethylene glycol , chemical engineering , etching (microfabrication) , nanotechnology , polyol , citric acid , nanorod , crystallography , organic chemistry , chemistry , composite material , layer (electronics) , engineering , polyurethane
We have successfully controlled the shape of gold nanocrystals through a simple and low‐cost hydrothermal method based on a modified polyol process. Well‐defined gold nanocrystals of icosahedral shape were synthesized in high yields by the rapid reduction of gold precursors with ethylene glycol (EG) in the presence of poly(vinyl pyrrolidone) (PVP) under hydrothermal conditions for 1 h. Truncated icosahedra (football‐shaped) have been prepared for the first time by prolonging the reaction time to 4 h. Both nanocrystal shapes were obtained quantitatively. Addition of citric acid inhibits the shape‐change process (from icosahedron to truncated icosahedron) by blocking oxidative etching, while addition of Fe(III) facilitates the shape‐change process by enhancing oxidative etching. We propose that growth of truncated icosahedra can be induced and maintained through interplay of the following processes: generation of multiple twinned seeds, shape‐ and size‐focusing by Ostwald ripening, and oxidative etching and preferential growth on the {100} face.