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).

Ce0.9Y0.1O1.95 and Ce0.8Y0.2O1.9 are synthesized by reaction of Sr2Ce0.9Y0.1O3.95 and Sr2Ce0.8Y0.2O3.9 in 100% CO2 at 600-800°C for 12 h, followed by HCl treatment. The samples are characterized by powder XRD, SEM, and electrical conductivity measurements. Their bulk ionic conductivity is about one and half orders of magnitude higher than that of undoped CeO 2 and comparable to those of ceramic-and wet-chemical-method synthesized rare-earth doped CeO2. -(GERLACH, R. G.; BHELLA, S. S.; THANGADURAI*, V.; Inorg. Chem. 48 (2009) 1, 257-266; Dep. Chem., Univ. Calgary, Calgary, Alberta T2N 1N4, Can.; Eng.) -W. Pewestorf 12-005