Self-ordered nanotube formation from nickel oxide via submerged arc in water

A partially H-terminated nickel oxide nanotube is firstly realized by transformation from NiO via a method using submerged arc in water. The diameter of this nanotube is less than 5 nm, and its wall is atomically thin. It is speculated that the decomposition of NiO at a hot-temperature arc plasma followed by hydrogenation in a bubble generates NiOOH, known as a layer structure, and the asymmetric H-termination on its surface causes self-curling, resulting in nanotube formation. A molecular mechanics calculation indicates that the energetically favorable structure has H atoms at the inner side of nanotubes. (C) 2016 The Japan Society of Applied Physics