Synthesis and thermal transformations of layered double hydroxide containing samarium

Abstract

Nickel-aluminum layered double hydroxide with aluminum ions partially substituted by samarium ones was successfully synthesized via coprecipitation followed by hydrothermal treatment. X-ray diffraction data showed that the obtained sample is single-phase material with hydrotalcite-like structure. The presence of samarium in the sample was confirmed by elemental analysis. Electron microscopy demonstrated that the compound consists of very small plate-like particles with a shape similar to hexagonal. The study of thermal transformations of the material revealed that it decomposed upon heating above 300 °C with the formation of mixed oxide, and spinel-type oxide was formed while the heating temperature was increased up to 1000 °C. The rehydration ability of the sample was rather limited: no reconstruction of layered structure took place after mixed oxide was formed. The “memory effect” was observed only after heating the hydroxide at a temperature not higher than 300 °C. The thermal properties of samarium-containing samples resemble closely those of nickel-containing hydrotalcites.