The Formation of Structural Defects in the Ce-Sm-O and Ce-Sm-O/Ru Nanosystems Synthesized by the Sol-Gel Method
Russian Journal of Physical Chemistry A
, E-ISSN: 1531-863X
Boreskov Institute of Catalysis SB RAS
Institute of Chemical Engineering and High Temperature Chemical Processes
Belarusian State University
The structure of Ce-Sm-O and Ce-Sm-O/Ru samples with 5, 10, and 15 at % Sm synthesized by the inorganic sol-gel method was characterized by EPR, X-ray diffraction, and electron microscopy. The thermal dehydration of xerogels of the products of cohydrolysis of Ce(IV) and Sm(IH) at 600-800 degrees C results in the formation of a structure on the basis of cubic CeO2 with particle sizes less than 10 rim. The EPR spectra of Ce-Sm-O contain signals of the Ce3+ (g(perpendicular to) = 1.966 and g(parallel to) = 1.947) and [SmOn-V-O] (g(parallel to) = 1.996-1.998 and g(perpendicular to) = 1.973-1.974) centers with different coordination environment symmetries. The introduction of Sm(III) decreases the concentration of volume Ce3+ centers to a greater degree the higher the content of Sm(III). After deposition of Ru(IV), the concentration of Ce3+ increases substantially, by one to two orders of magnitude, and surface Ce3+ ions appear (g(perpendicular to) = 1.966 and g(parallel to) = 1.940). Synthesis through the step of sol formation ensures homogeneous distribution of 10% Sm in the crystal lattice of CeO2.