Combined SANS and SAXS study of the action of ultrasound on the structure of amorphous zirconia gels

• Ultrasonication results in a dramatic increase in the surface fractal dimension of ZrO2 × xH2O.
• SANS and SAXS prove a similar effect of sonication on the mesostructure of ZrO2 × xH2O.
• Ultrasonication increases the specific surface area of ZrO2 × xH2O.

In the present work, we have studied for the first time the combined effect of both sonication and precipitation pH on the structure of amorphous zirconia gels synthesized from zirconium(IV) propoxide. The techniques of small-angle neutron and X-ray scattering (SANS and SAXS) and low temperature nitrogen adsorption provided the integral data on the changes in the microstructure and mesostructure of these materials caused by ultrasonic (US) treatment. Amorphous ZrO2·xH2O synthesized under ultrasonic treatment was found to possess a very structured surface, characterized by the surface fractal dimension 2.9–3.0, compared to 2.3–2.5 for the non US-assisted synthesis, and it was also found to possess a higher specific surface area, while the sizes of the primary particles remain unchanged.