Thermal Stabilization of Ce_xZr_1-xO₂Oxygen Storage Promoters by Addition of Al₂O₃: Effect of Thermal Aging on Textural, Structural, and Morphological Properties

Thermal stability and dispersion of CeO 2 supported on Al 2 O 3 is greatly improved by insertion of ZrO 2 into the CeO 2 lattice. It is shown that homogeneous nanosized Ce x Zr 1 - x O 2 solid solutions can be prepared on the Al 2 O 3 surface by using a citrate complexation synthesis method. Investigation of effects of Ce x Zr 1 - x O 2 composition and loading of the Ce 0.2 Zr 0.8 O 2 phase on thermal stability and nanostructure of the prepared materials revealed that strong interactions between the supported phase and Al 2 O 3 are induced by the high-temperature treatment. High contents of ZrO 2, choice of the Ce x Zr 1 - x O 2 precursors, and loading of the mixed oxide are critical factors leading to nanocomposite systems with high thermal and structural stability, consisting of particles of Ce 0.2 Zr 0.8 O 2 as small as 9−20 nm in close contact with a θ-Al 2 O 3 matrix even after calcination at 1373 K. The enhanced stability of the present materials was confirmed also under hydrothermal conditions.