Manufacture of substitute natural gas (SNG) using high temperature methanation of synthesis gas is becoming important due to high energy prices. a wish for a stable energy supply, and diminishing natural gas in some areas. Maintaining the activity and stability of the catalyst after exposure to high temperatures is crucial for the process. At 600 degrees C, loss of active surface area proceeds via the atom migration sintering mechanism. The methanation reaction is structure sensitive and it is suggested that atomic step sites play the important role as the active sites of the reaction. (C) 2007 Elsevier B.V. All rights reserved.