[Zurück]

Z. Jakub, J. Hulva, P. Ryan, D. Duncan, D. Payne, R. Bliem, M. Ulreich, P. Hofeggger, F. Kraushofer, M. Meier, M. Schmid, U. Diebold, G. Parkinson:
"Adsorbate-induced structural evolution changes the mechanism of CO oxidation on a Rh/Fe₃O₄ model catalyst";
Nanoscale, 12 (2020), S. 5866 - 5875.

The structure of a catalyst often changes in reactive environments, and following the structural evolutionis crucial for the identification of the catalyst´s active phase and reaction mechanism. Here we present anatomic-scale study of CO oxidation on a model Rh/Fe3O4(001)"single-atom"catalyst, which has a verydifferent evolution depending on which of the two reactants, O2or CO, is adsorbedfirst. Using tempera-ture-programmed desorption (TPD) combined with scanning tunneling microscopy (STM) and X-rayphotoelectron spectroscopy (XPS), we show that O2destabilizes Rh atoms, leading to the formation ofRhxOyclusters; these catalyze CO oxidationviaa Langmuir-Hinshelwood mechanism at temperatures aslow as 200 K. If CO adsorbsfirst, the system is poisoned for direct interaction with O2, and CO oxidationis dominated by a Mars-van-Krevelen pathway at 480 K.

http://dx.doi.org/10.1039/c9nr10087c

https://pubs.rsc.org/en/content/articlelanding/2020/NR/C9NR10087C#!divAbstract