Relative stability of armchair, zigzag and reczag graphene edges on the Ru(0001) surface

► Stability of 3 types of graphene nanoribbons on Ru(0001) is studied with DFT. ► While the reczag edge is more stable in vacuo, the zigzag edge is more stable on Ru. ► The zigzag and armchair edges are almost isoenergetic on the Ru surface. ► The graphene edges interact strongly with the surface causing the ribbons to buckle. ► Charge transfer is observed from the Ru surface to ribbon edges.