Oxygen storage capacity effect

Lanthanum oxide is valence invariant, and does not exhibit any oxygen storage capacity, but it effectively stabilizes 5/-AI2O3. It spreads over the alumina surface and provides a barrier against dissolution of rhodium in the support. 

Figure 7.5. Evolution of the oxygen storage capacity (OSC) as a function of temperature. Effect of the metal (a tr. Rh) and the support (CeO broken lines. Ceo ftjZrojTOz full lines).

The evolution of the oxygen storage capacity (OSC in pmol-CO.g ) is given in Fig. 6 as a function of the amount of praseodymium in the solids. For both series, the introduction of praseodymium induces an increase of the OSC up to x = 0.50, whereas above x = 0.50, a decrease is observed. Therefore, an excess of praseodymium has a negative effect on the OSC [17-19]. In order to understand how praseodymium can influence the oxygen storage capacity, calculated OSC values were obtained as follows ... 

EFFECTS OF SINTERING AND OF ADDITIVES ON THE OXYGEN STORAGE CAPACITY OF PtRh CATALYSTS. 

The behavior of modified Rli/Ce02-Al203 catalyst is shown in Fig.5. Contrarily to what was found on AI2O3, for modified catalysts supported on ceria-alumina, chlorine has only a sliglit effect on the OSC values. This difference would be result of the presence of ceria that could promote a better distribution of chlorine at the carrier surface. Sulfates would increase the oxygen storage capacity of the modified catalyst. This effect would only be apparent and would be due partly to the sulflir reduction by CO which masks the inliibitor effect of sulfur on OSC. This can be observed by comparison with the oxygen mobilities. 

The aim of these studies was to examine the effect of the heteroatoms on the surface texture and the porosity of ceria, as well as the chemistry of the surface in terms of surface groups present and surface acidity (or basicity), as well as on bulk properties such as crystcd structure and oxygen storage capacity. Vanadium was chosen because of the multiplicity of oxidation states in which it can be present. In previous studies, copper as a guest ion was shown to increase the BET surface area of ceria in certain concentrations. Iron was chosen because of... 

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