Ce1-xRuxO2-δ (x=0.05, 0.10): a new high oxygen storage material and Pt, Pd-free three-way catalyst

Singh, Preetam ; Hegde, M. S. (2009) Ce1-xRuxO2-δ (x=0.05, 0.10): a new high oxygen storage material and Pt, Pd-free three-way catalyst Chemistry of Materials, 21 (14). pp. 3337-3345. ISSN 0897-4756

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Official URL: http://pubs.acs.org/doi/abs/10.1021/cm900875s

Related URL: http://dx.doi.org/10.1021/cm900875s


Nanocrystalline Ce1-xRuxO2-δ (x=0.05 and 0.10) of 8-10 nm sizes have been synthesized by hydrothermal method using melamine as complexing agent. Compounds have been characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and energy-dispersive X-ray analysis (EDX) and their structures have been refined by the Rietveld method. The compounds crystallize in fluorite structure and the composition is Ce1-xRuxO2-x/2 where Ru is in +4 state and Ce is in mixed-valence (+3, +4) state. Substitution of Ru4+ ion in CeO2 activated the lattice oxygen. Ce1-xRuxO2-x/2 reversibly releases 0.22[O] and 0.42[O] for x=0.05 and 0.10, respectively, which is higher than the maximum possible OSC of 0.22 [O] observed for Ce0.50Zr0.50O2. Utilization of Higher OSC of Ce1-xRuxO2-δ (x=0.05 and 0.10) is also reflected in terms of low-temperature CO oxidation with these catalysts, both in the presence and absence of feed oxygen. The Ru4+ ion acts as an active center for reducing molecules (CO, hydrocarbon "HC") and oxide ion vacancy acts as an active center for O2 and NO, leading to low-temperature NO conversion to N2. Thus due to Ru4+ ion, Ce1-xRuxO2-δ is not just a high oxygen storage material but also shows high activity toward CO, hydrocarbon "HC" oxidation, and NO reduction by CO at low temperature with high N2 selectivity for three-way catalysis.

Item Type:Article
Source:Copyright of this article belongs to American Chemical Society.
ID Code:16331
Deposited On:15 Nov 2010 13:50
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