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When More Is Less: Nonmonotonic Trends in Adsorption on Clusters in Alloy Surfaces

preprint
submitted on 17.06.2020 and posted on 19.06.2020 by Abigale Monasterial, Calla Hinderks, Songkun Viriyavaree, Matthew Montemore

Single-atom alloys can be effective catalysts and have been compared to supported single-atom catalysts. To rationally design single-atom alloys and other surfaces with localized ensembles, it is crucial to understand variations in reactivity when varying the dopant and the ensemble size. Here, we examined hydrogen adsorption on surfaces embedded with localized clusters and discovered general trends. Counterintuitively, increasing the amount of a more reactive metal sometimes makes a surface site less reactive. This behavior is due to the localized electronic states in many of these surfaces, making them similar to free-standing nanoclusters. Further, single-atom alloys have qualitatively different behavior than larger ensembles. Specifically, the adsorption energy is U-shaped when plotted against the dopant’s group for single atom alloys. Additionally, adsorption energies on single atom alloys correlate more strongly with the dopant’s p-band center than the d-band center.

Funding

NSF DMR-1852274

Louisiana Board of Regents LEQSF(2019-22)-RD-A-20

History

Email Address of Submitting Author

mmontemore@tulane.edu

Institution

Tulane University

Country

United States

ORCID For Submitting Author

0000-0002-4157-1745

Declaration of Conflict of Interest

No conflict of interest

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