Samarium colloids prepared in organic solvents and active solids

Abstract

International audienceSamarium colloids in organic solvents (2-methoxyethanol, 2-propanol, 2-propanone, and 1,2-dimethoxyethane) were obtained by the chemical liquid deposition (CLD) method at 77 K. The colloids were characterized by electron diffraction, energy-dispersive X-ray (EDX), UV-Vis spectroscopy, kinetic stability, and electrophoretic measurements. The colloid stability depends on the solvent used and the metal concentration. The higher stability was obtained in 2-methoxyethanol, which is in agreement with previous results for other lanthanide colloids. The zeta potential (zeta) of the colloids ranges between 0.138 and 1.945 mV. The UV-Vis spectra exhibit bands characteristic of the solvent. The 2-methoxyethanol shows bands at 205 and 234 nm very similar to the 2-propanol which exhibits bands at 202 and 253 nm for 2.5E-4 M concentration. However, bands for 1,2-dimethoxyethane and 2-propanone colloids were impossible to determine due to their highest extinction coefficient values. A dependence of the UV/Vis spectral properties of these new sol materials with Sm(III) is described. In all cases, the EDX analyses confirm the presence of metal in the colloids. The electron diffraction gives the most common (hkl) planes corresponding to Sm and Sm2O3 (211) and (100), respectively. As shown by the particle size distribution determined from transmission electron microscopy (TEM), the Sm-2-methoxyethanol colloids exhibit ranges from 1.6 and 2.9 nm, but the Sm-2-propanol colloids show ranges from 2.3 to 2.5 nm; the medium particle size of Sm-1,2-dimetoxyethane colloid is 0.8 nm, and the Sm-2-propanone colloids have a range from 1.0 and 4.3 nm, exhibiting a solvent polarity dependence. Also, active solids from the evaporation of the colloids which have been fully characterized by several chemical and physical techniques have been obtained