Stability of nanocrystalline Ce-Gd mixed oxide on Al2O3 support

摘要: Abstract In various technological applications (solid oxide fuel cells, heterogeneous catalysis) ceria based mixed oxides are in contact with alumina used as support or additive. It is thus important to gain knowledge on the possible interactions between and at temperatures atmospheres, corresponding real processing working conditions. this work, structure chemical stability of Ce0.5Gd0.5O1.75 nanoparticles supported a high surface γ-Al2O3 were studied oxidizing reducing atmosphere by XRD, TEM, SEM-EDS, STEM-EDS, Raman spectroscopy H2-TPR. Application reverse microemulsion method enabled synthesis highly Gd-doped, homogeneous particles mean size ∼2 nm, ideal for studies effect interaction Al2O3 structural od doped ceria. Poor tolerance sintering greatly improved their dispersion support. chemically stable up 1100 °C, undergoing little increase crystallite 7 nm. hydrogen atmosphere, limited complex, Gd support, which has been detail first time. started spread over 600 °C into nanometer thick amorphous layer, 900 °C crystallized (Gd,Ce)4Al2O9 aluminate. The aluminate, an intermediate phase low ceria/alumina molar ratio used, decomposed 1000 °C tetragonal CeAlO3 hexagonal GdAlO3. When deposited Al2O3, showed much reducibility, especially low-temperature range (300–600 °C). This further enhanced spreading occurring during treatment elevated temperature. nanocrystalline Ce-Gd-O/Al2O3 system prepared impregnation aqueous solution Ce nitrates appeared be inhomogeneous less both atmospheres.d