2007 Volume 15 Pages 89-95
In this project, wet chemical approaches for synthesizing metal nanocubes were investigated together with their applications. As one of the typical results, a facile synthetic method of monodisperse 85-nm Pd nanocubes in aqueous solution at room temperature was developed. By using cetyltrimethylammonium bromide (CTAB) as a capping reagent and reducing K2PdCl6 by ascorbic acid, the formation of 85-nm Pd nanocubes was clearly confirmed by observing the images with a field-emission scanning electron microscopy (FE-SEM). After the dispersion into pure water and the casting on the glassy carbon surfaces, Pd nanocubes were found to assemble to form the two-dimensional square array presumably due to the effect of CTAB. In addition, after just allowing the Pd nanocubes lie onto a smooth glassy carbon surface in solution, a flat and continuous structure of assembled Pd nanocubes could be formed on the glassy carbon surface. As the second example, we demonstrated a facile method for the preparation of the Pd nanobricks which comprised of atomic-step defects on the nanocrystals surface for the first time. By simply controlling the reaction parameters including the CTAB to hexamethylenetetramine (HMT) ratio and the ascorbic acid concentration, large scale Pd nanobricks structure could be prepared. These new structures should find extensively used in catalysis, surface-enhanced Raman scattering, magnetic and opto-electronics, due to their unique shapes and surface structure. Furthermore, some trials were performed for wet chemical preparation of Cu2O nanocubes. While suitable conditions to form Cu2O nanocubes were established, sphere and star-shaped Cu2O nanocubes were formed depending on the synthetic conditions. These results imply the possibilities of wet chemical approaches to control the shapes of metal nanoparticles by just changing the synthetic conditions.