Oxygen-induced morphological changes of Ag nanoclusters supported on TiO2(110)

The effect of insitu O2 exposure on TiO2(110)-supported Ag nanoclusters was investigated using X-ray photoelectron spectroscopy (XPS) and scanning tunneling microscopy (STM). An oxygen-induced cluster ripening was observed by STM after Ag/TiO2(110) was exposed to 10.00 Torr O2 for 2 h in an elevated-pressure reactor. The Ag clusters exhibit a clear bimodal size distribution after O2 exposure due to Ostwald ripening: some clusters increase in size while other clusters decrease in size. The cluster density also increased 5–15% after O2 exposure, indicating redispersion simultaneously occurs with ripening. It is shown that intercluster transport is likely accomplished through the formation of Ag2O.