Hydrothermal growth of zirconia nanobars on zirconium oxide

Abstract

Zirconia nanorods and nanoparticles were grown hydrothermally starting from zirconium monoxide powder. The process was performed in an autoclave using NaOH as a mineralizer at nominal concentrations 15 M, 20 Mand 25 M, and at a temperature of 200 °C for 1 week. The samples were characterized by high resolution transmission electron microscopy, showing that the nanorod diameter spanned from 25 to 200 nm and their length from a few hundred nm up to 2 μm. X-ray photoelectron spectrometry showed that after the treatment all the material was zirconium (IV) oxide, as confirmed by X-ray diffraction and selected area electron diffraction. The latter showed that the nanobars were in the monoclinic phase and the nanopowders in the tetragonal one.