Stability and Hydrogen Affinity of Graphite-Supported Wires of Cu, Ag, Au, Ni, Pd, and Pt

Abstract

The stability of Cu, Ag, Au, Ni, Pd, and Pt nanowires supported on graphite steps is investigated by density functional theory. Two step borders are examined: armchair and zigzag. It was found that the Ni, Pd, and Pt wires are more stable than coinage metal ones and that the zigzag configuration is the most energetically favored. The adsorption of hydrogen on such systems is also studied. In Ni, Pd, and Pt graphite-supported wires the reaction occurs on the wire, while in coinage metal wires hydrogen adsorbs directly on graphite steps, breaking the bond between wire and step. Our results suggest that, in early stages of wire formation, hydrogen adsorption could induce the desorption of coinage metals from graphite. The catalytic properties for hydrogen adsorption on graphite-supported and freestanding nanowires are also compared.