Growth and Characterization of Two-Dimensional FeO Nanoislands Supported on Pt(111)

Two-dimensional (2D) FeO nanoislands with a well-controlled size, density, and surface structure have been grown on Pt(111) by a two-step preparation process, which consists of Fe deposition at low temperatures, such as 150 K, in an O-2 atmosphere and subsequent annealing at elevated temperatures in ultrahigh vacuum. The atomic structure, chemical composition, and electronic state of the formed FeO nanoislands were investigated by scanning tunneling microscopy (STM), X-ray photoelectron spectroscopy, and high-resolution electron energy loss spectroscopy. The formation of the metastable 2D Fe surface phase can be attributed to confinement effects at interfaces between nanostructured oxides and metal substrates, which originate from the strong interaction between FeO and Pt(111). Furthermore, the STM and scanning tunneling spectroscopic data indicate that the formed Pt-FeO boundaries or edges of the FeO nanoislands present distinct chemical and electronic characteristics, which could be highly active in many catalytic processes.