We have found that the surface reaction on Pt(1 1 1) induced by the collision of supersonic methane molecules with a sufficiently high kinetic energy (670 meV) results in huge domains of highly oriented monolayer graphite without any unidentified carbon-related materials, and that the monolayer graphite completely covers the Pt(1 1 1) surface. The mechanism is discussed in terms of the surface insensitivity of the collision-induced process and the thermal stability of the graphite with a specific superstructure. This implies the effectiveness of supersonic molecular beam to the practical surface modification. (C) 2004 Elsevier B.V. All rights reserved.