Density-functional calculations were performed to examine the interface between graphene and a Pt(1 1 1) or Pt(1 1 1)/Ru-ML surface. Interfacial Ru atoms were found to make the interface more stable and carbon vacancies on graphene enhanced the interaction between graphene and multi-layer metal surfaces. The CO chemisorption energy on metal surfaces on graphene was calculated to clarify the effect of the catalyst carrier. (c) 2005 Elsevier B.V. All rights reserved.