Noble metal ionic catalysts: correlation of increase in CO oxidation activity with increasing effective charge on Pd ion in Pd ion substituted Ce1-xMxO2-delta (M = Ti, Zr and Hf)

Baidya, Tinku and Dutta, Gargi and Hegde, MS and Waghmare, Umesh V (2009) Noble metal ionic catalysts: correlation of increase in CO oxidation activity with increasing effective charge on Pd ion in Pd ion substituted Ce1-xMxO2-delta (M = Ti, Zr and Hf). In: Dalton Transactions (3). pp. 455-464.

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Abstract

Pd ion substituted Ce1-xMxO2- (M = Ti, Zr, Hf) have been prepared by a single step solution combustion method. Two atom% Pd ion substitution in the title compounds is confirmed by X-ray diffraction (XRD) and Pd ion charge state and redox properties have been determined by X-ray photoelectron spectroscopy (XPS) and H2/TPR studies. While Pd ion in CeO2 (Ce0.98Pd0.02O2-) showed higher catalytic activity for CO oxidation than Pd metal impregnated over CeO2, further increase in the catalytic activity is observed with Pd ion in Ce1-xTi(Hf)xO2 and a decrease in the activity with Pd ion in Ce1-xZrxO2. Effective charge on Pd ion could be varied by its substitution in these solid solutions Ce1-xMxO2 (M = Ti, Zr & Hf) and also in TiO2 compared to Pd ion in PdO. Effective positive charge on Pd ion is determined from the core level binding energy shift of Pd(3d5/2) peak with respect to Pd metal. Rate of CO oxidation increased and activation energy decreased with increase in effective charge on the Pd ion in the Pd ion substituted fluorites.

Item Type:	Journal Article
Additional Information:	Copyright of this article belongs to Royal Society of Chemistry.
Department/Centre:	Division of Chemical Sciences > Solid State & Structural Chemistry Unit
Date Deposited:	03 Nov 2009 09:55
Last Modified:	19 Sep 2010 05:00
URI:	http://eprints.iisc.ernet.in/id/eprint/18182

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