Facile Conversion of Layered Ruddlesden−Popper-Related Structure Y₂O₃-Doped Sr₂CeO₄ into Fast Oxide Ion-Conducting Fluorite-Type Y₂O₃-Doped CeO₂

Abstract

The present work shows a new solid- and gas-phase reaction technique for the preparation of a fast oxide-ion-conducting Y(2)O(3)-doped Ce(1-x)Y(x)O(2-delta) (x = 0.1, 0.2) (YCO), which involves the reaction of layered (Ruddlesden-Popper K(2)NiF(4)-type) structure Y(2)O(3)-doped Sr(2)CeO(4) (YSCO) with CO(2) at an elevated temperature and subsequent acid-washing. A powder X-ray diffraction study revealed the formation of a single-phase cubic fluorite-type YCO for the CO(2)-reacted and subsequent acid-washed product. Energy dispersive X-ray analysis showed the absence of Sr in the CO(2)-treated and subsequent acid-washed product, confirming the transformation of layered YSCO into YCO. The cubic lattice constant was found to decrease with increasing Y content in YCO, which is consistent with the other YCO samples reported in the literature. The scanning electron microscopy study showed smaller-sized particles for the product obtained after CO(2)- and acid-washed YCO samples, while the high-temperature sintered YCO and the precursor YSCO exhibit larger-sized particles. The bulk ionic conductivity of the present CO(2)-capture-method-prepared YCO exhibits about one and half orders of magnitude higher electrical conductivity than that of the undoped CeO(2) and was found to be comparable to those of ceramic- and wet-chemical-method synthesized rare-earth-doped CeO(2).

Synthesis, Structure and Electrical Properties of Mo‐doped CeO2–Materials for SOFCs

“…The appearance of a spike at the 1 MHz value, quite visible especially at high temperature, is due to an artefact of the instrument. We have observed a similar effect for Ta-doped double perovskite-type Ba 3 CaNb 2 O 9 and In-doped CeO 2 [47,48]. It is also important to point out that this artefact was found to vary with total impedance of the system.…”

TEM and ED confirmation of conversion of 3D and 2D perovskite-type into fluorite-type structure

“…The diffraction rings of this amorphous gold were used to confirm a proper calibration in diffraction mode of the equipment. found to be consistent with ex situ and in situ X-ray studies [12,14,15]. The PXRD of CO 2 mediated synthesized Ce 0.…”

“…Our group has employed a new two steps synthesis to stabilize indium-doped CeO 2 structure, which was not attainable by a regular mixed-oxide solid-state reaction at 800-1500 • C [12][13][14][15]. This approach involves leaching of alkaline from the perovskite and its related structure precursors under CO 2 at elevated temperatures and subsequent acid washing.…”

Challenges and prospects of anodes for solid oxide fuel cells (SOFCs)

“…Sr 2 PbO 4 -type MIECs Gerlach et al first explored a unconventional "solid state and CO 2 mediated gas phase" synthesis method for acceptor-doped CeO 2 to control the homogeneity and microstructure of the particles [81]. The homogenous and Fig.…”