Oxygen storage properties

Bunluesin, T., Gorte, R.J., and Graham, G.W. 1998. Studies of the water-gas-shift reaction on ceria-supported Pt, Pd, and Rh Implications for oxygen-storage properties. Appl. Catal. B Environ. 15 107-14. 

Ceria is studied as a component in the formulation of catalysts for several environmental processes. The most important are reviewed in this book (see. Chapters 10, 12, 14). The oxygen storage properties of ceria play a key role in all these applications. 

The first part of the book deals with fundamental characteristics of ceria from the point of view of catalytic applications. After an introductory chapter on production, mining and safety issues, a series of chapters (chp. 2-7) cover structural properties, preparation chemistry and fundamentals of eharacterization and redox/oxygen storage properties. A specific section (chp. 6) has been dedicated to ceria-zirconia due to the importance this material has in current three-way catalysis for auto-exhaust treatment. To complete the first part there is a chapter on computational studies (chp. 8) and one on the properties of ceria surfaces and films as model for catalytic studies (chp. 9). 

In the case of the La2Cuo.9Pdo.i04+s catalyst, we have seen that the mixed oxide structure collapses in the presence of CO, and although the easy reduction and oxidation of the well-dispersed copper and palladium seems to be sufficient to compensate for the variations in the composition, it is difficult to invoke real oxygen storage properties for this solid. 

C.E. Hori, 1998, Thermal stability of oxygen storage properties in a mixed CeCh-ZrCh system, Appl. Catal. B Environ., 16,105-117. 

Exothermic Decompositions These decompositions are nearly always irreversible. Sohds with such behavior include oxygen-containing salts and such nitrogen compounds as azides and metal styphnates. When several gaseous products are formed, reversal would require an unlikely complex of reactions. Commercial interest in such materials is more in their storage properties than as a source of desirable products, although ammonium nitrate is an important explosive. A few typical exampes will be cited to indicate the ranges of reaction conditions. They are taken from the review by Brown et al. ( Reactions in the Solid State, in Bamford and Tipper, Comprehensive Chemical Kinetics, vol. 22, Elsevier, 1980). 

The CeO CejOs System The redox properties ofceria and ceria-based materials have been studied in great detail because of their oxygen storage and release capacities, which are highly relevant for their application in modem three-way automotive catalysts [6, 7]. Unfortunately, the temperatures used in these studies are usually far lower than those necessary for thermal reduction in inert atmospheres. Therefore, the applicability of these data must be regarded as limited. Some case studies of ceria-based systems in solarthermal cycles are published in the literature [2,4,14] ... 

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