Abstract:
Oxide nanoparticles exhibit unique features such as high surface area, enhanced catalytic activity, and
tunable optical and electrical properties, making them valuable to various industry applications as
well as for the development of new research projects. Nowadays, ZrO2 nanoparticles are widely used
as catalysts and precursors in ceramic technology. Hydrothermal synthesis with metal salts is one of
the most common methods for producing stable tetragonal-phase zirconium dioxide nanoparticles.
However, hydrothermal synthesis requires relatively high process temperatures (160–200 °C) and
the use of advanced heat-resistant autoclaves capable of maintaining high pressure. This paper
investigates how different precursors (ZrOCl₂·8H₂O and ZrO(NO₃)₂·2H₂O) and synthesis temperatures
(110–160 °C) affect the phase composition, optical properties, size, and shape of ZrO₂ nanoparticles
produced by hydrothermal synthesis without calcination. In addition, the effect of temperature
exposure in the range of 100–1000 °C on the phase stability of the synthesized nanoparticles
was studied. X-ray diffraction and Raman spectroscopy techniques were used to determine the
structure and phase composition, while the optical properties were examined through the analysis
of transmission and absorption spectra in the visible and UV ranges. It was found that the obtained
particles at synthesis temperatures of 110–130 °C have predominantly cubic c-ZrO2 phase, which
changes to monoclinic phase when heated above 500 °C. Analysis of visible and UV spectroscopy
data reveals that the experimental samples have pronounced absorption in the middle UV range
(200–260 nm) and have an energy band gap Eg varying from 4.8 to 5.1 eV. The hydrothermal powders
synthesized in this study can be used as absorbers in the mid-UV range and as reinforcing additives in
the preparation of technical ceramics.
