By changing a number of variables during the electrodeposition of lead, Xiao et al. show that they can obtain a wide range of micrometer-scale shapes and architectures-- including snowflake shapes. The deposition occurred from solutions of lead nitrate and lead acetate, with highly oriented pyrolytic graphite as the substrate and at pH above 3.0 to prevent the evolution of large hydrogen bubbles. In general, individual particles of triangular, hexagonal, octahedral, decahedral, and icosahedral shape were obtained when the voltages were close to the thermodynamic equilibrium potential. At higher reduction potentials, nanowires, nanobrushes, monopods, and multipods were obtained. The synthesis is similar to the growth of colloidal particles, where higher concentrations lead to more elongated particles. For colloids, particle growth is often directed by capping layers that prevent certain faces from growing; similar effects are seen in lead electrodeposition, where a snowflake structure can be obtained through the addition of ethanol. -- MSL
J. Am. Chem. Soc. 10.1021/ja0315154 (2004).
