Oxygen powdered perovskites

Other oxygen ion conductors that have potential use as solid electrolytes in electrochemical devices are stabilized bismuth and cerium oxides and oxide compounds with the perovskite and pyrochlore crystal structures. The ionic conductivity and related properties of these compounds in comparison with those of the standard yttria-stabilized zirconia (YSZ) electrolyte are briefly described in this section. Many of the powder preparation and ceramic fabrication techniques described above for zirconia-based electrolytes can be adapted to these alternative conductors and are not discussed further. 

Tabata et al. [177] and Seyama [178] both described significant differences in the chemical composition of the surface, due to Sr segregation, compared with the bulk composition in a series of powders Lai. Sr CoOs. This indicates a behaviour of the surface different from that of the bulk in these compoimds. Not only can this account for a number of observations made in the total oxidation of CO and CH4, as discussed by the authors, but it is also considered to be an important factor when one tries to correlate the composition of a perovskite with its activity in surface oxygen exchange. 

In the FTIR spectra of the LSM powders calcined between 500 and 900 °C, displayed in Fig. 5, a band located at 603 cm"i is attributed to M - O (metal - oxygen) stretching, and is characteristic of the perovskite structure. On the other hand, bands corresponding to carbon bonds, particularly carboxyl groups are visible in 1000 - 2500 cm"i interval. The two absorption bands at 1460 cm"i and 2360 cm i are due to C=0 vibration and can be related to traces of carbonate. In the range of 3300 - 3670 cm i a band corresponding to O - H bond can be attributed to adsorbed water due to the contact of the sample with the environment. With this information and the XRD analyses, it became clear that the carbonate content of the synthesized powders decreases and even vanishes at higher calcination temperatures. 

Lao.6Sro.4Co03 (LSCO) is one of typical perovskite oxides and expected to be applied to a semipeimeable device and electrode for oxygen because of its high catalytic activity in oxygenation [1-9]. The mixed oxide is usually prepared by solid phase reaction from the respective oxide powders or pyrolysis of a mixture of the acetates [2-6], but it is difficult to obtain the... 

Buffat, P. Perret, D. Xanthopoulos, N. Bucheli, O. (2005). Characterization of Perovskite Powders for Cathode and Oxygen Membranes Made by Different Synthesis Routes. Jowmal of the European Ceramic Society, Vol. 25, No.l2, (March 2005), pp. 1991-1995, ISSN 0955-2219... 

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