Probing adsorption sites for CO on ceria
Kumudu Mudiyanselage1, Hyun You Kim, Sanjaya D Senanayake
1Chemistry Department, Brookhaven National Laboratory, Upton, NY 11973, USA. djs@bnl.gov.
Physical Chemistry Chemical Physics : PCCP
|August 15, 2013
Summary
This study identifies CO adsorption sites on ceria-based catalysts using spectroscopy and calculations. Carbon monoxide (CO) adsorption on Ce(3+) sites was observed, distinguishing their presence on catalyst surfaces.
Area of Science:
- Heterogeneous catalysis
- Surface science
- Materials chemistry
Background:
- Ceria catalysts are vital for CO conversion reactions like oxidation and water-gas shift.
- Understanding CO adsorption sites on catalysts is crucial for elucidating reaction mechanisms.
- Ceria's variable oxidation states complicate surface analysis.
Purpose of the Study:
- To investigate CO adsorption on CuOx/Cu(111) and CeOx/Cu(111) systems.
- To distinguish the presence of Ce(3+) cations using CO as a probe molecule.
- To support experimental findings with theoretical calculations.
Main Methods:
- Infrared reflection absorption spectroscopy (IRRAS)
- X-ray photoelectron spectroscopy (XPS)
- Density functional theory (DFT) calculations
Main Results:
- Distinct IR peaks for CO adsorbed on different copper oxide phases on Cu(111) were identified.
- CO adsorption on Ce(3+) sites on CeOx/Cu(111) was observed at elevated CO pressures and low temperatures (IR peak at 2162 cm(-1)).
- DFT calculations corroborated experimental results, confirming CO's utility in identifying Ce(3+) sites.
Conclusions:
- CO adsorption behavior differs significantly between copper oxide and ceria sites.
- CO can be used as a reliable probe molecule to identify Ce(3+) cations on catalyst surfaces.
- This work advances the understanding of structure-activity relationships in ceria-based catalysts.
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