Structural and morphological properties of Ce(1−x)FexO2−δ synthesized by citrate route.

Cerium-based materials were intensively studied in last years because of their high oxygen storage capacity (OSC) associated to the reversible Ce 4+ ↔Ce 3+ process and their properties closely related to the defect chemistry that could be adjusted by adequate selection of dopant. Fe 3+ cation, due to its effective ionic radius smaller than that of Ce 4+ , is an interesting doping agent. In this work we present the synthesis and characterization of Ce (1− x ) Fe x O 2− δ mixed oxides (0≤ x ≤1) synthesized by the so named “citrate method”. Our X-ray diffraction results suggest a rather strong dependence of lattice parameter on nanocrystal size, while Raman spectroscopy evidenced the formation of a small volume fraction of hematite clusters in samples with relatively high iron content, x ≥0.15, not observable in X-ray diffraction experiments. The solid solutions exhibit high porosity and specific surface area, with nearly 10% of pore volume in the micropore size range, making these materials potentially useful for applications in catalysis. [ABSTRACT FROM AUTHOR]