Platinum-Iron(II) Oxide Sites Directly Responsible for Preferential Carbon Monoxide Oxidation at Ambient Temperature: An Operando X-ray Absorption Spectroscopy Study** |
| |
Authors: | Ilia I Sadykov Dr Vitaly L Sushkevich Dr Frank Krumeich Dr Rob Jeremiah G Nuguid Prof?Dr Jeroen A van Bokhoven Dr Maarten Nachtegaal Dr Olga V Safonova |
| |
Institution: | 1. Energy and Environment Research Division, Paul Scherrer Institute, Forschungsstrasse 111, 5232 Villigen, Switzerland;2. Institute for Chemical and Bioengineering, ETH Zürich, Wolfgang-Pauli-Strasse 10, 8093 Zürich, Switzerland |
| |
Abstract: | Operando X-ray absorption spectroscopy identified that the concentration of Fe2+ species in the working state-of-the-art Pt?FeOx catalysts quantitatively correlates to their preferential carbon monoxide oxidation steady-state reaction rate at ambient temperature. Deactivation of such catalysts with time on stream originates from irreversible oxidation of active Fe2+ sites. The active Fe2+ species are presumably Fe+2O?2 clusters in contact with platinum nanoparticles; they coexist with spectator trivalent oxidic iron (Fe3+) and metallic iron (Fe0) partially alloyed with platinum. The concentration of active sites and, therefore, the catalyst activity strongly depends on the pretreatment conditions. Fe2+ is the resting state of the active sites in the preferential carbon monoxide oxidation cycle. |
| |
Keywords: | Heterogeneous Catalysis Operando Pt?Fe Structure–Activity Relationships X-Ray Absorption Spectroscopy |
|
|