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The morphology and electronic structure of vapor-deposited Cu nanoparticles on a fully oxidized CeO2(111) surface at 300 K have been investigated by X-ray photoelectron spectroscopy (XPS), synchrotron radiation photoemission spectroscopy (SRPES), and scanning tunneling microscopy (STM). Cu nanoparticles were found dispersed on the CeO2 surface with a tendency to nucleate at step edges at very low coverage. The Cu atoms are oxidized to Cu+ upon deposition on CeO2 at 300 K, and this is accompanied by the partial reduction of the CeO2 thin film, as evidenced by the Cu LVV and Ce 3d spectra. Deposition of Cu above 0.5 monolayer (ML) gives rise to neutral Cu atoms and to the growth of two-layer Cu particles. These results indicate the presence of electronic metal–support interaction at the Cu/CeO2 interface, which involves electron transfer across the metal/support interface. Combining the SRPES and STM results, this charge transfer from Cu to CeO2 was quantified. It was found that the average charge transfer is largest at 0.22 ML (particle containing about 94 Cu atoms), where approximately one electron is transferred per Cu atom from Cu to CeO2, which agrees well with the Cu LVV result. Such quantitative insights will help to characterize the chemical state of active species and improve the understanding of particle size effects and the electronic metal–support interaction.

Assembly and tessellation of organic species at surfaces are important for the design of advanced materials, particularly for the development of spontaneous self-assemblies of supramolecular systems of increasing complexity. However, there are few examples where the ability to steer the system between supramolecular tessellations has been achieved. Here, we demonstrate a series of steps to reduce and then restore molecular symmetry; those variations impact vertex symmetry and thus generate a series of tessellations that reflect the molecular symmetry. We deposit 4,4′-dihydroxybiphenyl on the Ag(111) surface, then anneal at specific temperatures to achieve stepwise dehydrogenation of the terminal hydroxyls. The symmetry of tessellation vertices in the self-assembled structure also changes, as characterized by scanning tunneling microscopy and synchrotron radiation photoemission spectroscopy. This control over vertex geometry and spontaneous tessellation structure extends our understanding of supramolecular design control and advances architectural complexity for the development of functional surfaces.