Synthesis and structural properties of ultra-small oxide (TiO2, ZrO2, SnO2) nanoparticles prepared by decomposition of metal alkoxides

The decomposition of metal (Ti, Zr, Sn) alkoxides at 250 degrees C in a solution of tetradecene and dodecylamine resulted in the formation of ultra-small (1-2 nm) oxide nanoparticles. The nanoparticles showed unusual structural properties. The high-pressure orthorhombic phase was found for SnO2. The as-synthesized ZrO2 nanoparticles were only partially crystallized. It was possible to observe their in situ crystallization under the TEM beam. The TiO2 nanoparticles appeared amorphous, with only a few nanocrystals dispersed in the sample. The temperature evolution of the samples was investigated in situ by Raman spectroscopy. All SnO2 was converted to stable cassiterite at 350 degrees C. TiO2 and ZrO2 samples displayed phase stability reversal over a broad range of temperatures. (C) 2010 Elsevier B.V. All rights reserved.