Continuous Flow Synthesis of Yttria‐Stabilized‐Zirconia Nanocrystals in Supercritical Solvothermal Conditions

AbstractThe synthesis of yttria‐stabilized zirconia nanoparticles with a fine control on the chemical composition and the distribution of yttrium cations is of major interest to master the mechanical, optical or ionic conduction properties of the final material. However, a fine control of this chemical homogeneity within the particles, especially above 5 mol.% of yttria (Y2O3), is challenging with conventional synthesis routes. In the present study, for the first time the interest of using supercritical sol–gel like synthesis is demonstrated for the continuous production in a single step of high quality zirconia (ZrO2) nanocrystals of 7 nm stabilized with Y2O3 without post‐treatment. Three compositions are investigated, i.e., 1.5, 3, and 8 mol.% of Y2O3 and in‐depth physico‐ chemical characterizations such as X‐ray diffraction, total X‐ray scattering, High‐resolution electron microscopy, Raman and X‐ray photoelectron spectroscopy are performed to asses and thus prove the successful synthesis of these different compositions while keeping a good chemical homogeneity. This enables to confirm that this original process leads to a unique and fine structural control for such small yttria‐doped zirconia nanocrystals.