Operando XANES Reveals the Chemical State of Iron-Oxide Monolayers During Low-Temperature CO Oxidation
Artikel i vetenskaplig tidskrift, 2024
We have used grazing incidence X-ray absorption near edge spectroscopy (XANES) to investigate the behavior of monolayer FeO x ${_x }$ films on Pt(111) under near ambient pressure CO oxidation conditions with a total gas pressure of 1 bar. Spectra indicate reversible changes during oxidation and reduction by O 2 ${_2 }$ and CO at 150 degrees C, attributed to a transformation between FeO bilayer and FeO 2 ${_2 }$ trilayer phases. The trilayer phase is also reduced upon heating in CO+O 2 ${_2 }$ , consistent with a Mars-van-Krevelen type mechanism for CO oxidation. At higher temperatures, the monolayer film dewets the surface, resulting in a loss of the observed reducibility. A similar iron oxide film prepared on Au(111) shows little sign of reduction or oxidation under the same conditions. The results highlight the unique properties of monolayer FeO and the importance of the Pt support in this reaction. The study furthermore demonstrates the power of grazing-incidence XAFS for in situ studies of these model catalysts under realistic conditions.
Thin films
Operando
XAFS
Iron oxide
Heterogeneous catalysis
Författare
Dorotea Gajdek
Malmö universitet
Lunds universitet
Harald J. Wallander
Lunds universitet
Malmö universitet
Giuseppe Abbondanza
Chalmers, Fysik, Kemisk fysik
Gary S. Harlow
University of Oregon
Johan Gustafson
Lunds universitet
Sara Blomberg
Lunds universitet
Per-Anders Carlsson
Chalmers, Kemi och kemiteknik, Tillämpad kemi
Justus Just
Lunds universitet
Edvin Lundgren
Lunds universitet
Lindsay R. Merte
Lunds universitet
Malmö universitet
ChemPhysChem
1439-4235 (ISSN) 1439-7641 (eISSN)
Vol. In PressUtveckling av röntgentekniker och nya Ga-zeotyper för produktion av gröna aromater
Vetenskapsrådet (VR) (2023-06344), 2024-01-01 -- 2027-12-31.
Ämneskategorier (SSIF 2011)
Den kondenserade materiens fysik
DOI
10.1002/cphc.202400835
PubMed
39403857