Role of Cyclic Ether and Solvent in a Non-Alkoxide Sol−Gel Synthesis of Yttria-Stabilized Zirconia Nanoparticles

Abstract

The effects of cyclic ether (epoxide versus oxetane), solvent, and drying method were examined for a non-alkoxide sol−gel synthesis of yttria-stabilized zirconia (YSZ). YSZ sol−gel materials, from 3 to 25 mol % Y2O3, were successfully prepared with either propylene oxide (PO) or trimethylene oxide (TMO) in both aqueous and mixed ethanol−water solutions of Zr4+ and Y3+ chlorides. Supercritical drying (aerogels) produced fine, nanoparticulate networks, whereas drying under ambient conditions (xerogels) resulted in heterogeneous micrometer-sized hard agglomerates. The resulting materials were characterized using powder X-ray diffraction (XRD), Raman spectroscopy, transmission electron microscopy, scanning electron microscopy, nitrogen adsorption/desorption analysis, and elemental analysis by inductively coupled plasma−atomic emission spectroscopy. The cyclic ether and solvent were found to be critical factors in the resulting as-prepared aerogel surface area and morphology. For a given solvent, aerogels prepared with PO had higher surface areas than did those prepared with TMO. For example, the surface areas of aerogels prepared in water were 453 and 295 m2/g for PO and TMO, respectively. Following calcination to 550 °C, however, the crystallized YSZ powders were similar, consisting of homogeneous nanoparticles (∼10 nm) with spherical morphologies and high surface areas (>100 m2/g). Elemental analysis, XRD, and electron microscopy indicated that Y2O3 and ZrO2 formed a homogeneous nanostructure over a wide range of Zr/Y ratios, corresponding to 3−25 mol % Y2O3.

Defective by design: vanadium-substituted iron oxide nanoarchitectures as cation-insertion hosts for electrochemical charge storage

“…21 Epoxide-based sol-gel chemistry is a versatile route to synthesize iron oxides 21 25,[30][31][32][33][34] Hydrated metal chlorides are the most common precursors due to their high solubility in alcohols and water, and because chloride anions act on the protonated epoxide via nucleophilic attack to shi the equilibrium of the hydrolysis/condensation reactions. 21 Epoxide-based sol-gel chemistry is a versatile route to synthesize iron oxides 21 25,[30][31][32][33][34] Hydrated metal chlorides are the most common precursors due to their high solubility in alcohols and water, and because chloride anions act on the protonated epoxide via nucleophilic attack to shi the equilibrium of the hydrolysis/condensation reactions.…”

Synthesis of Yttria‐Stabilized Zirconia Nanopowders by a Thermal Plasma Process

“…6(b) also displayed peaks for tetragonal phase, but the observed peaks from 200 to 700 cm −1 were mostly broad and the intensities of the peaks were reduced, which indicates less tetragonal characteristics than the 4YSZ in Fig. 6(a) 41,42 . Also, the broad peak near 646 cm −1 observed in Fig.…”

“…The EDS analysis was performed with a standard‐less approach and no repetition as well was conducted on samples, which might cause an inaccuracy in this measurement. It has been reported that the amount of yttria‐doping affects the zirconia phase 41,43 . Chervin et al 41 investigated the phase transition of yttria‐stabilized zirconia over the range of 3–25 mol% yttria.…”

A Robust Approach to Inorganic Aerogels: The Use of Epoxides in Sol–Gel Synthesis

“…Numerous examples of mixed metal oxide aerogels prepared by epoxide-initiated gelation have been reported in the literature. Solid state electrolyte materials, such as yttria-stabilized zirconia (YSZ), have been prepared using this approach [39,40]. Strontium-doped lanthanum manganite (LSM) materials for use as cathodes in solid oxide fuel cells have also been fabricated using the epoxide method [41].…”