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Time-Resolved, In Situ DRIFTS/EDE/MS Studies on Alumina-Supported Rhodium Catalysts: Effects of Ceriation and Zirconiation on Rhodium-CO Interactions

DOI: 10.1002/cphc.201402122 DOI Help
PMID: 25044889 PMID Help

Authors: Anna Kroner (Diamond Light Source) , Mark Newton (European Synchrotron Radiation Facility) , Moniek Tromp (Southampton University) , Otello M. Roscioni (Southampton University) , Andrea E. Russell (Southampton University) , Andrew Dent (Diamond Light Source Ltd) , Carmelo Prestipino (Institut des Sciences Chimiques de Rennes) , John Evans (Southampton University)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Chemphyschem , VOL 15 (14) , PAGES 3049 - 3059

State: Published (Approved)
Published: October 2014

Open Access Open Access

Abstract: The effects of ceria and zirconia on the structure–function properties of supported rhodium catalysts (1.6 and 4 wt % Rh/γ-Al2O3) during CO exposure are described. Ceria and zirconia are introduced through two preparation methods: 1) ceria is deposited on γ-Al2O3 from [Ce(acac)3] and rhodium metal is subsequently added, and 2) through the controlled surface modification (CSM) technique, which involves the decomposition of [M(acac)x] (M=Ce, x=3; M=Zr, x=4) on Rh/γ-Al2O3. The structure–function correlations of ceria and/or zirconia-doped rhodium catalysts are investigated by diffuse reflectance infrared Fourier-transform spectroscopy/energy-dispersive extended X-ray absorption spectroscopy/mass spectrometry (DRIFTS/EDE/MS) under time-resolved, in situ conditions. CeOx and ZrO2 facilitate the protection of Rh particles against extensive oxidation in air and CO. Larger Rh core particles of ceriated and zirconiated Rh catalysts prepared by CSM are observed and compared with Rh/γ-Al2O3 samples, whereas supported Rh particles are easily disrupted by CO forming mononuclear Rh geminal dicarbonyl species. DRIFTS results indicate that, through the interaction of CO with ceriated Rh particles, a significantly larger amount of linear CO species form; this suggests the predominance of a metallic Rh phase.

Journal Keywords: Analytical methods; cerium; rhodium; supported catalysts; zirconium

Subject Areas: Chemistry

Facility: ESRF