Mesoscopic restructuring and mass transport of metal atoms during reduction of the Ag(111)-p(4×4)-O surface with CO

The reduction of the Ag(111)-p(4x4)-O surface oxide with CO was used to study the restructuring of the surface during reaction. Scanning tunneling microscopy images taken during the reaction show the formation of Ag islands and pits within the reacted areas surrounded by unreacted p(4x4)-O. The number of Ag adatoms incorporated in the Ag(111)-p(4x4)-O structure was determined to be 12 from the areas of these islands and pits. The evolution of the reacted area with exposure to CO indicates that direct reaction with the Ag(111)-p(4x4)-O is not preferred, but that the boundary between the p(4x4) and the freshly created Ag(111) surface is the source of the reactive oxygen.