Oxygen storage capacity reduction/oxidation

Since there are many transition metal and rare earth oxides with two or more stable valencies, there would seem to be many candidates available for buffering the A/F oscillations in the gas phase. Yet only one, cerium oxide, has achieved widespread use. Were it not for ceria, the TWC strategy could never be implemented. The key, as noted above, is the rate of interconversion between oxidation states. Perturbation frequencies on cars are in the vicinity of 1 Hz. The OSC (oxygen storage capacity) component must keep up with this if it is to contribute to conversion. This means that both oxidation and reduction must be rapid. 

This process was used to synthesize a number of perovskite formulations, which were then extensively characterized for their catalytic properties such as oxygen storage capacity [49], water vapor sensitivity [50], conversion of CO and exhaust gas emissions [48], sensitivity to CO adsorption [39,40], reduction of NO by propene [51-53], reduction of NO either by CO [54] or by C3H5 [55-58], synthesis of higher alcohols [56,59], CO hydrogenation [60], oxidation of stearic acid [61], and methanol [62]. 

---