Oxygen storage capacity

High levels of sulfur not only form dangerous oxides, but they also tend to poison the catalyst in the catalytic converter. As it flows over the catalyst in the exliaust system, the sulfur decreases conversion efficiency and limits the catalyst s oxygen storage capacity. With the converter working at less than maximum efficiency, the exhaust entering the atmosphere contains increased concentrations, not only of the sulfur oxides but also, of hydrocarbons, nitrogen oxides, carbon monoxides, toxic metals, and particulate matter. 

Ceria is another type of mixed conducting oxide which has been shown already to induce electrochemical promotion.71 Ceria is a catalyst support of increasing technological importance.73 Due to its nonstoichiometry and significant oxygen storage capacity it is also often used as a promoting additive on other supports (e.g. y-A Cb) in automobile exhaust catalysts.79 It is a fluorite type oxide with predominant n-type semiconductivity. The contribution of its ionic conductivity has been estimated to be 1-3% at 350°C.71... 

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. 

Fally, F., Perrichon, V., Vidal, H. et al. (2000) Modification of the oxygen storage capacity of Ce02—Zr02 mixed oxides after redox cycling aging, Catal. Today, 59, 373. 

Daganello, F. and Martorana, A. (2002) Phase analysis and oxygen storage capacity of ceria-lanthana-based TWC promoters prepared by sol-gel routes, J. Sol. State Chem. 163, 527. 

TPR is suitable for characterization of the catalysts, it is not ideal for determining the oxygen storage capacity of the material (43). 

For zirconia-doped ceria it was shown that redox cycling can enhance the oxygen storage capacity, see F. Fally, V. Perrichon, H. Vidal, J. Kaspar, G. Blanco, J. M. Pintado, S. Bernal, G. Colon, M. Daturi, J.C. Lavalley, Catalysis Today, 59, 373 (2000). 

OSC—oxygen storage capacity. 6 OSCC—oxygen storage capacity minus uptake of the supported metal. 

Figure 7.6 Oxygen storage capacity of the Cu02Ce08O2 y catalyst. Empty squares represent CO oxidation, and empty circles the conversion of H20 in WGS reaction. Filled squares and filled circles are CO and H20 conversions respectively, in WGS reaction. The dotted line represents the WGS reaction equilibrium curve. The solid line is model fit assuming first-order reversible kinetics. (Reprinted from [51], With permission from Elsevier.)...

The oxygen storage capacity of Ce02-Zr02 catalysts was correlated in the past to the concentration of these oxide ion species. Samples 8A and 6A showed signals at g = 2.36 and 2.21, respectively, due to a small amount of Ni substituted in the... 

Royer, S., Alamdari, H., Duprez, D., Kaliaguine, S., Oxygen storage capacity of Lai. xAxB03 perovskites (with A=Sr, Ce B=Co, Mn) - Relation to the catalytic activity in CH4 oxidation reaction,Catal, B Environmental, 2005, Volume 58, 273-288. 

Fig. 14. Oxygen storage capacity and oxygen release rates at 500°C.

S. Lundgren and E. Jobson, Deterioration of Three-Way Automotive Catalysts, Part II—Oxygen Storage Capacity at Exhaust Conditions, SAE 930944, Society of Automotive Engineers, Warrendale, Pa., 1993. 

For the Selox reaction, the oxidation mechanism may involve oxygen species that are stored in/over the catalyst support, such the ceria-based materials used in three-ways catalytic exhaust systems [16]. Consequently, the oxygen storage capacity (OSC) can also be considered as an objective function, if one assumes or dem-... 

C) Oxygen storage capacity from transient TPH. mmol Hgfl 1 catalyst... 

---