Structural changes of AgO chains on Ag(1 1 0) by photo- and CO-induced oxygen elimination

We have investigated the structural changes in the added-rows of Ag–O chains at a Ag(1 1 0)(2×1)-O surface due to photo- and CO-induced elimination of O by using scanning tunneling microscopy. The photo-induced elimination occurs only on the surface containing carbidic carbon, resulting in the structural change of the added-rows from (2×1) to (4×1) according to the reduction of O coverage (θO). The structural change due to the CO-induced elimination depends on the carbon coverage: the (2×1) structure is retained in spite of the decrease of θO for the C-contained surface, while the structure changes sequentially from (2×1) to (4×1) and (6×1) for the carbon-free surface. Furthermore, the CO-induced elimination rate in the low θO on the carbon-free surface is much faster than that on the C-contained surface. These results indicate that the small amount of C atoms play an important role not only in the structural changes associated with the oxygen elimination reactions but also in the kinetics of the oxidation reaction of CO.