Thermally Induced Transformation from Cu/FeO/Pt(111) to CuPt₃/FeO/Pt(111)

Understanding the precise structure is the initial step of exploring synergistic effect between transition metal and oxide support in heterogeneous catalysis. In this work, the growth and thermal stability of Cu on FeO/Pt(111) were systematically investigated using various surface science techniques, including scanning tunneling microscopy (STM), angle-resolved X-ray photoelectron spectroscopy (AR-XPS) and infrared reflection absorption spectroscopy (IRAS). Room temperature (RT) deposition results in randomly distributed Cu clusters on the FeO surface, which undergoes negligible changes at low annealing temperatures (below 600 K). After annealing at 800 K, the Cu/FeO/Pt(111) system transforms to a new structure composed of two types of islands with different heights and morphologies, where the irregular islands are identified as CuPt₃ alloys and the islands with a Moiré structure are the second layer of FeO, thus forming a CuPt₃/FeO interface. Our work provides two model systems, Cu/FeO/Pt(111) and CuPt₃/FeO/Pt(111), which can be used to study the catalytic properties of the Cu-FeO or CuPt₃-FeO interface using surface science approaches.