Synthesis and Catalytic Activity of Highly Dispersed Solid Solutions Ce0.9Sn0.1O2 and Ce0.8Sn0.1Zr0.1O2 in CO Oxidation

Fluorite-like solid solutions of Ce 0.9 Sn 0.1 O 2 and Ce 0.8 Sn 0.1 Zr 0.1 O 2 were synthesized by coprecipitation using ammonium carbonate as a precipitant. The samples were characterized by X-ray powder diffraction analysis, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy, low-temperature nitrogen adsorption, and gas chromatography. It was shown that the solid solutions are formed already at an annealing temperature of 550°C. In this process, platelike particles are formed, the size of which, according to SEM data, is 4 μm. The synthesized materials have a mesoporous structure. The specific surface areas of Ce 0.9 Sn 0.1 O 2 and Ce 0.8 Zr 0.1 Sn 0.1 O 2 samples are 80.6 and 76.3 m 2 /g, respectively. Calcination at a temperature of 800°C leads to an increase in the particle size up to 8–10 μm. The specific surface area after calcination is the highest (15.3 m 2 /g) for the Ce 0.8 Zr 0.1 Sn 0.1 O 2 sample, which is due to the presence of zirconium ions in its composition. The synthesized materials demonstrated high activity in CO oxidation. The maximum catalytic activity was observed for the two-component system Ce 0.9 Sn 0.1 O 2 : T 50% at 180°C and T 90% at 236°C. Of the samples calcined at a temperature of 800°C, Ce 0.8 Zr 0.1 Sn 0.1 O 2 is the most active, which is due to the formation of a more heat-resistant system in comparison with cerium dioxide and Ce 0.9 Sn 0.1 O 2 . To increase the thermal stability, it is advisable to dope the two-component material Ce 0.9 Sn 0.1 O 2 with Zr +4 ions.