Dresden 2017 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 81: Oxide and Insulator Surfaces: Adsorption II
O 81.6: Vortrag
Mittwoch, 22. März 2017, 17:15–17:30, WIL C107
Theoretical Description of the Adsorption of Water and Ethanol on Pt4/Pt(111) and Pt4/CeO2(111) Substrates — •Yohanna Seminovski1, Polina Tereshchuk1, Adam Kiejna2, and Juarez L. F. Da Silva1 — 1São Carlos Institute of Chemistry, University of São Paulo, São Carlos, SP, Brazil — 2Institute of Experimental Physics, University of Wrocław, Wrocław, Poland
Pt-ceria, which has been proposed as catalyst for H2 production in ethanol steam reforming reaction process, show formation of partially reduced Ce cations because of charge transfer from Pt transition metal towards oxide surface.[1] However, the role of the independent active adsorption sites on TMn/CeO2(111) substrates is not well understood yet. For instance, it is not known if the cationic Pt sites coexistent with the newly formed Ce3+ influence the adsorption properties of molecule on the substrates. In this work,[2] we applied DFT+U to study the active sites and the role of partial cationic charge of the Pt atoms on the adsorption properties of water and ethanol (probe molecules) on four selected substrates, Pt(111), Pt4/Pt(111), CeO2(111), and Pt4/CeO2(111). Results show each molecule preferentially located in the cationic sites of the base of the tetrahedron Pt4 cluster, while in the anionic, lower-coordinated Pt atom sites located on the cluster-top or in the surface Ce and O sites the molecule adsorption is less favored. The Ce3+ atoms aren not found to be directly involved in the adsorption process of molecules, however these are important in the stabilization of the substrate.[1]P. Tereshchuk et al., PCCP 17, 13520 (2015) [2]Y. Seminovski et al., JCP 145, 124709 (2016)