Influence of carbon nanotube on the structure evolution of Ni–Cu alloy nanorod

Abstract.

A Monte Carlo method has been performed to simulate the structure evolution of Ni–Cu alloy nanorods encapsulated in the carbon nanotube and removed from the carbon nanotube. The Sutton-Chen many-body potential and Lennard-Jones potential are used to describe the metal-metal and metal-carbon interactions, respectively. The studies show that all Ni–Cu atoms in carbon nanotube are arranged in a series of concentric cylindrical layers even they have different fractions, and Cu atoms are apt to stay at the surface layers. If the carbon nanotube was removed, Ni–Cu alloy nanorod would turn into a cluster with nickel core and copper shell. The physical origin for such structure formation and evolution toward core-shell motifs are discussed. The bond pair analysis shows that the nanorods and clusters are amorphous structures dominated by the rhombohedral structure and mixed up with some local short-range order.