Observation of water dissociation on nanometer-sized FeO islands grown on Pt(1Â 1Â 1)

► FeO(1 1 1) nanoislands grown on Pt(1 1 1) are active for water dissociation, even at 80 K. ► The coordinatively unsaturated Fe atoms at the island edges are attributed to the active centers. ► Hydroxyls are diffusive on FeO nanoislands and are able to desorb as H2 and H2O at room temperature, leaving oxygen vacancy chain on FeO islands.