Promoter Effect of Early Stage Grown Surface Oxides: A Near-Ambient-Pressure XPS Study of CO Oxidation on PtSn Bimetallics.
The knowledge of the catalyst active phase on the atomic scale under realistic working conditions is the key for designing new and more efficient materials. In this context, the investigation of CO oxidation on the bimetallic Pt3Sn(111) surfaces by near-ambient-pressure X-ray photoelectron spectroscopy and density functional theory calculations illustrates how combining advanced methodologies allows the determination of the nature of the active phase. Starting from 300 K and 500 mTorr of oxygen, the progressive formation of surface oxides is observed with increasing temperature: SnO, PtO units first, and SnO2, PtO2 units afterward. For CO oxidation on the (2 × 2) surface, the activity gain is assigned to the build-up of ultrathin domains composed of SnO and SnO2 units. The formation of these early stage surface oxides is entirely supported by a density functional theory analysis. More generally, this study demonstrates how the catalyst surface oxidation and transformation can be better controlled by a relevant choice of environmental conditions.
†Institut de Recherche sur la Catalyse et l'Environnement de Lyon, UMR 5256 CNRS-Université Lyon 1, 69626 Villeurbanne Cedex, France.
Yvette
Y
Jugnet
‡Ecole Normale Supérieure de Lyon, Laboratoire de Chimie, UMR 5182 CNRS-Université de Lyon, 69364 Lyon Cedex 07, France.
David
D
Loffreda
†Institut de Recherche sur la Catalyse et l'Environnement de Lyon, UMR 5256 CNRS-Université Lyon 1, 69626 Villeurbanne Cedex, France.|‡Ecole Normale Supérieure de Lyon, Laboratoire de Chimie, UMR 5182 CNRS-Université de Lyon, 69364 Lyon Cedex 07, France.
Céline
C
Dupont
‡Ecole Normale Supérieure de Lyon, Laboratoire de Chimie, UMR 5182 CNRS-Université de Lyon, 69364 Lyon Cedex 07, France.
Françoise
F
Delbecq
†Institut de Recherche sur la Catalyse et l'Environnement de Lyon, UMR 5256 CNRS-Université Lyon 1, 69626 Villeurbanne Cedex, France.
Eric
E
Ehret
†Institut de Recherche sur la Catalyse et l'Environnement de Lyon, UMR 5256 CNRS-Université Lyon 1, 69626 Villeurbanne Cedex, France.
Francisco J
FJ
Cadete Santos Aires
¶Department of Applied Physics, Hanyang University, ERICA, Korea 426-791.
Bongjin S
BS
Mun
§Department of Physics, Faculty of Arts and Sciences, Nigde University, 51240 Nigde, Turkey.|∥Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States.
Funda
F
Aksoy Akgul
∥Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States.
Zhi
Z
Liu
CO oxidation; DFT; alloy; near-ambient-pressure XPS; oxidation; single crystal