Dynamic formation of reaction sites at nanostructured one-dimensional surface compounds

Scanning tunneling microscopy is utilized to investigate the structural changes of AgO chains on clean and carbidic-carbon containing Ag(110) surfaces under UV photoirradiation and CO exposure. Although AgO chains are arranged with the (2x1)structure on both of the surfaces, AgO chains are bundled to make the (2x1) bands on the C-containing surface, whereas they make much larger domains on the entire surface of clean Ag(110). The photo-induced elimination of O in AgO chains ccurs only on the C-containing surface. Kinetics of oxygen elimination by CO exposure are very different between the two surfaces. Oxygen coverage decreases steadily on the C-containing surface with CO exposure, whereas the reaction is accelerated in the lower O coverage range where AgO chains with (nx1)(n≥4) configurations show significant structural fluctuation. Comparison between the two surfaces and simulations based on the Ising model indicate that the acceleration of the reaction originates from the dynamical formation of active O adatoms by fluctuation of AgO chains.

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