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Hexagonal YFe1−xPdxO3−δ: Nonperovskite Host Compounds for Pd2+ and Their Catalytic Activity for CO Oxidation



Jun Li, Udayshankar G. Singh, Thomas D. Schladt, Judith K. Stalick, Susannah L. Scott, Ram Seshadri


Metastable YFeO3 with the hexagonal YAlO3 structure was obtained by a sol−gel process at 700 °C, using metal nitrate precursors with pH control and the appropriate citric acid to nitrate ratio. Under similar conditions, YFe1−xPdxO3−δ (0 < x ≤ 0.1) compositions were also prepared. The substitution of Fe by Pd stabilizes the YAlO3 structure at higher temperatures. The crystal structures of YFe1−xPdxO3−δ (0 ≤ x ≤ 0.1) were refined by Rietveld analysis of X-ray and neutron powder diffraction data. The parent hexagonal YFeO3 (x = 0) crystallizes in the space group P63/mmc with a = 3.5099(3) Å and c = 11.759(2) Å. The redox-driven mobility of Pd to integrate into the oxide host as ions and to dissociate from it as fcc-Pd nanoparticles was monitored by a combination of X-ray diffraction and X-ray photoelectron spectroscopy. Pd nanoparticles in the reduced samples were detected by scanning backscattered electron microscopy and transmission electron microscopy. The Pd2+-containing materials showed significant low-temperature (near 100 °C) catalytic activity for CO oxidation, comparable to that of highly dispersed PdO/Al2O3, despite their relatively low surface areas.
Chemistry of Materials


catalysis, nanoparticles, neutron diffraction


Li, J. , Singh, U. , Schladt, T. , Stalick, J. , Scott, S. and Seshadri, R. (2008), Hexagonal YFe1&#8722;xPdxO3&#8722;&#948;: Nonperovskite Host Compounds for Pd2+ and Their Catalytic Activity for CO Oxidation, Chemistry of Materials, [online],, (Accessed April 19, 2024)
Created September 25, 2008, Updated March 18, 2024