On the growth mechanisms of polar (100) surfaces of ceria on copper (100)

•Growth study of nanometer-sized CeO2 (100) islands on Cu (100) using low-energy electron microscopy and photoemission electron microscopy.•Real-time observation of three-way interaction between the ceria, substrate, and local oxygen chemical potential.•Nucleation of ceria islands initiates a reorientation of the substrate's terrace boundaries.•Grown ceria islands are fully stoichiometric CeO2 (100) with (2 × 2) reconstruction and form suitable model system for heterogeneous catalysis. We present a study of temperature dependent growth of nano-sized ceria islands on a Cu (100) substrate. Low-energy electron microscopy, micro-electron diffraction, X-ray absorption spectroscopy, and photoemission electron microscopy are used to determine the morphology, shape, chemical state, and crystal structure of the grown islands. Utilizing real-time observation capabilities, we reveal a three-way interaction between the ceria, substrate, and local oxygen chemical potential. The interaction manifests in the reorientation of terrace boundaries on the Cu (100) substrate, characteristic of the transition between oxidized and metallic surface. The reorientation is initiated at nucleation sites of ceria islands, whose growth direction is influenced by the proximity of the terrace boundaries. The grown ceria islands were identified as fully stoichiometric CeO2 (100) surfaces with a (2 × 2) reconstruction. [Display omitted]