Evidence of a single-wall platinum nanotube

A suspended platinum nanowire was observed to have the same helical multishell structure (HMS) that was reported for gold nanowires thinner than 2 nm. The investigation was made in an ultrahigh vacuum high-resolution electron microscope (JEM-2000VF). The platinum nanowire was synthesized by an electron-beam thinning method at elevated temperatures to enhance the Pt atom migration. A platinum multishell nanowire was thinned by migration until it finally snapped. In the meantime, the outer shell was stripped from a 13-6 HMS to partially expose the inner shell. Simulated electron microscope images supported that the exposed inner shell was a single-wall tube having a tunnel at the wire axis.