Structure and chemical properties of CeO2 on a curved Cu(111) crystal

Abstract

Resumen del póster presentado al DPG Spring Meetings, celebrado de forma virtual del 1 al 4 de marzo de 2021.The system CeOx/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 CeOx/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 Bstep 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 22º with respect to (111). STM measurements reveal that the CeO2 structures mainly cover the Cu(111), leaving the (223) facet CeO2 free.Peer reviewe