Atomically Resolved Structure of Monolayer Ceria Island on Pt(111)

Ceria supported on platinum substrate is one of the most extensively studied inverse model catalysts. Unraveling the atomic structure of the ceria film is of great importance in helping understand the performance of ceria-involving heterogeneous catalysis. In this study, scanning tunneling microscopy (STM), apparent local work function (LWF) measurement, and density functional theory (DFT) calculations are employed to explore the atomic structures of the ceria islands and their electronic interaction with the Pt(111) substrate. High-resolution STM images and DFT calculations have unraveled the atomic structures of the prepared 3:4 coincidence cells and the island step edges on Pt(111). In specific, the structural difference between the two triangular half units is unprecedentedly achieved on the atomic level. The charge transfer between the ceria island and Pt(111) dependent on the interfacial structure has also been uncovered by apparent LWF measurements.