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arXiv · 2406.03016

A Multi-Technique Study of C2H4 Adsorption on a Model Single-Atom Rh1 Catalyst

Chunlei Wang·Panukorn Sombut·Lena Puntscher·Manuel Ulreich·Jiri Pavelec·David Rath·Jan Balajka·Matthias Meier·Michael Schmid·Ulrike Diebold·Cesare Franchini·Gareth S. Parkinson
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Abstract

Single-atom catalysts are potentially ideal model systems to investigate structure-function relationships in catalysis, if the active sites can be uniquely determined. In this work, we study the interaction of C2H4 with a model Rh/Fe3O4(001) catalyst that features 2-, 5-, and 6-fold coordinated Rh adatoms, as well as Rh clusters. Using multiple surface-sensitive techniques in combination with calculations of density functional theory (DFT), we follow the thermal evolution of the system and disentangle the behavior of the different species. C2H4 adsorption is strongest at the 2-fold coordinated Rh1 with a DFT-determined adsorption energy of -2.26 eV. However, desorption occurs at lower temperatures than expected because the Rh migrates into substitutional sites within the support, where the molecule is more weakly bound. Adsorption at the 5-fold coordinated Rh sites is predicated to -1.49 eV, but the superposition of this signal with that from small Rh clusters and additional heterogeneity leads to a broad C2H4 desorption shoulder in TPD above room temperature.

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Chunlei Wang, Panukorn Sombut, Lena Puntscher, Manuel Ulreich, Jiri Pavelec, David Rath, Jan Balajka, Matthias Meier, Michael Schmid, Ulrike Diebold, Cesare Franchini, Gareth S. Parkinson. 2024-06-05. A Multi-Technique Study of C2H4 Adsorption on a Model Single-Atom Rh1 Catalyst. https://doi.org/10.1021/acs.jpcc.3c03684

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