Scanning tunnelling microscopy was used to monitor changes in surface structure during the reaction of formic acid and methanol with O pre-covered (110) surfaces. The reactivity pattern of O on the surface was markedly coverage-dependent and reactant-dependent. This was attributed partly to the nature of the p(2 x 1) O-layer itself; which consisted of an added-row structure with Cu-O chains in the [001] direction. The Cu at the ends of these chains was unstable, and tended to seek an alternative stable location during reaction. In this case of methanol, this location was associated with the methoxy layer itself. The formates which resulted from formic acid adsorption preferred to bond to the original surface layer; thus leaving Cu atoms to diffuse away. If the surface was partially covered by O, the Cu built up between diminishing O-islands and created a saw-tooth structure. When the surface was fully covered by a p(2 x 1) layer, the Cu could diffuse only over the (2 x 1) layer itself; where it was converted into a c(6 x 2) structure via rearrangement and compression of the original p(2 x 1) layer.

Gross Rearrangement of Metal Atoms during Surface Reactions M.Bowker, S.Poulston, R.A.Bennett, P.Stone: Journal of Physics - Condensed Matter, 1998, 10[35], 7713-22