The chemisorption of sulfur and CO was found to have profound effects on the structure of a stepped platinum surface. By itself, sulfur chemisorbs, forming a p(2 x 2) ordered structure, and induced doubling of the terrace widths and step heights. Subsequent co-adsorption of CO displaces the sulfur, compressing it to distances of √3 times the Pt lattice spacing, and induced surface re-structuring. New terraces formed which contain exclusively CO and were separated by monatomic steps from the terraces containing the compressed sulfur overlayer. This co-adsorbate induced restructuring phenomenon had strong implications in the mechanisms of surface catalyzed reactions.

Coadsorbate Induced Reconstruction of a Stepped Pt(111) Surface by Sulfur and CO - a Novel Surface Restructuring Mechanism Observed by Scanning Tunnelling Microscopy. J.D.Batteas, J.C.Dunphy, G.A.Somorjai, M.Salmeron: Physical Review Letters, 1996, 77, 534-7