Synthesis and characterization of low amount tin-doped ceria (CexSn1-xO2-δ) for catalytic CO oxidation

A series of CexSn1-xO2-delta oxides with low amount of tin (X >= 0.8) have been synthesized by coprecipitation, and characterized by a sort of techniques. All the prepared oxides were in the range of mesoporous materials. It was found that the incorporation of tin prevented the ceria crystallites growth. The solubility limit for tin-doped ceria oxide was found to be 22 at.%, and partial segregation of tin dioxide was found for sample with X = 0.8 by XRD, Raman, DRS UV-vis and XPS techniques. The microstrain of the mixed oxides, associated with the lattice defects, increased with the tin content, which affects the reducibility and OSC, which were higher for mixed oxides in comparison than for pure ceria and tin dioxide. The incorporation of tin into the ceria lattice increased the total surface acidity. XPS analysis showed that both 4+ and 3+ oxidation states for Ce, and metallic tin together with oxidized tin were present in the mixed oxides, being CO and Sn4+/2+ species the most abundant in the surface. The prepared CexSn1-xO2-delta mixed oxides showed to be very suitable as catalytic support for copper oxide in CO oxidation, especially for samples with X = 0.975 and 0.95. (C) 2014 Elsevier B.V. All rights reserved.