Metal-promoted restoration of defective graphene

Abstract

A novel metal-participating rearrangement mechanism of graphene is elucidated via density functional calculations. Results show that the barrier for the elimination of Stone–Wales defects can be decreased by the adsorbed transition metal atoms. Molecular orbital composition analysis shows that the contribution from the metal atom to the frontier orbital in the transition state is a key factor for the distinct metal catalytic properties. Among the chosen elements (Cu, Ni, Fe, Cr, Mo, and W), tungsten can reduce the activation energy remarkably from 6.2 to 2.9 eV, and 1000 K is regarded as a favorable temperature to yield perfect hexagonal nanographene. In contrast to curved network structures in fullerenes and carbon nanotubes, the open and planar structure of graphene helped to accommodate kinetic transformations of the carbon skeleton and metal atoms in favorable pathways.