[Zurück]

M. Meier, J. Hulva, Z. Jakub, F. Kraushofer, M. Bobic, R. Bliem, M. Setvin, M. Schmid, U. Diebold, C. Franchini, G. Parkinson:
"CO oxidation by Pt₂/Fe₃O₄: Metastable dimer and support configurations facilitate lattice oxygen extraction";
Science Advances, 8 (2022), eabn4580; S. 1 - 8.

Heterogeneous catalysts based on subnanometer metal clusters often exhibit strongly size-dependent proper-
ties, and the addition or removal of a single atom can make all the difference. Identifying the most active species
and deciphering the reaction mechanism is extremely difficult, however, because it is often not clear how the
catalyst evolves in operando. Here, we use a combination of atomically resolved scanning probe microscopies,
spectroscopic techniques, and density functional theory (DFT)-based calculations to study CO oxidation by a
model Pt/Fe3O4(001) "single-atom" catalyst. We demonstrate that (PtCO) 2 dimers, formed dynamically through
the agglomeration of mobile Pt-carbonyl species, catalyze a reaction involving the oxide support to form CO2. Pt2
dimers produce one CO 2 molecule before falling apart into two adatoms, releasing the second CO. Olattice ex-
traction only becomes facile when both the Pt-dimer and the Fe3O4 support can access metastable configurations,
suggesting that substantial, concerted rearrangements of both cluster and support must be considered for reac-
tions occurring at elevated temperature.

http://dx.doi.org/10.1126/sciadv.abn4580

https://publik.tuwien.ac.at/files/publik_303808.pdf