A Rationally Designed Route to the One-Pot Synthesis of Right Bipyramidal Nanocrystals of Copper

Lined with planar defects, nanoscale right bipyramids (RBPs) are of great interest for a variety of applications owing to the presence of a single type of {100} facets and two oppositely positioned right-angle corners as well as a higher surface-to-volume ratio than that of a cube. Here we report a rationally designed route to the facile synthesis of Cu RBPs with edge lengths controlled in the range 30–70 nm. The one-pot protocol involves the sequential reduction of Pd(II) and Cu(II) precursors, mixed at a molar ratio of 1:200, by glucose in the presence of hexadecylamine, a capping agent with strong binding to the Cu(100) surface. Because of the difference in standard reduction potential between the Pd(II)/Pd and Cu(II)/Cu pairs, the Pd(II) precursor is reduced first for the generation of Pd seeds lined with parallel planar defects, followed by the slow deposition of Cu atoms for the formation of RBPs. By varying the growth time and/or the amount of Pd(II) relative to Cu(II), Cu RBPs with tunable edge le...