SurfaceScience21 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 76: Poster Session VI: Supported nanoclusters: structure, reactions, catalysis

O 76.5: Poster

Mittwoch, 3. März 2021, 13:30–15:30, P

Structure and Chemical Properties of CeO₂ on a Curved Cu(111) Crystal — •Lorena Glatthaar^1,2, Khadiza Ali², J. Enrique Ortega², and Frederik Schiller² — ¹Physikalisch-Chemisches Institut, Justus Liebig University, D-35392 Giessen, Germany — ²Centro de Física de Materiales, E-20018 San Sebastián, Spain

The system CeO_x/Cu has attracted interest as an inverse catalyst for CO oxidation, water-gas shift and CO₂ hydrogenation. While previous work focused on characterizing this system and the named reactions on Cu(111) or with powdered samples, we investigated this system on the vicinal surfaces of Cu(111), which are shown to be much closer to a nanostructured catalysts compared to the low index surfaces. We grew CeO₂ on a curved Cu(111) single crystal with well defined vicinal surfaces and a continuous variation of step density depending on the vicinal angle. We characterized the CeO_x/Cu system with LEED, STM and XPS. XPS analysis indicates only Ce(IV) oxide formed regardless of the position on the curved crystal. On the Cu(111) part of the curved sample, CeO₂ nanostructures seems to grown on Cu-oxide areas, leaving the remaining Cu(111) surface uncovered. On both A- and B-step vicinal surfaces of the curved crystal, facets build up after CeO₂ deposition. The stable facets of the B-step vicinals are (111) and (110). At the A-step side three stable facets have been observed, namely the (111), (223) and an additional one at 22^∘ with respect to (111). STM measurements reveal that the CeO₂ structures mainly cover the Cu(111), leaving the (223) facet CeO₂ free.