Oxygen Storage Capacity Measurements

OSC measurements may be carried out in many different ways, depending essentially on the experimental conditions. The first option depends on how fast the gas composition is perturbed. One may distinguish lab-scale low frequency 

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Since OSC (Oxygen Storage Capacity) was introduced as a way of determining on quantitative basis the capability of ceria-based supports to release oxygen under reducing conditions, and to uptake it under oxidising conditions (359), numerous studies (35,98,160,180,186,203,249,337,341,354.362-367) have included OSC measurements, as a routine way of characterising the redox properties of these catalytic systems. 

Two different measurements of the oxygen storage capacity may be distinguished ... 

Oxygen Storage Capacities may be measured in many different ways depending on the operating conditions but also on the nature of the reducer and the oxidant. Four different combinations are reviewed hereafler. 

Oxygen storage capacity (OSC) was measured at 400°C under atmospheric pressure. A 20 mg sample was continuously purged with helium (30 cm. min ). Successive or alternate pulses (0.265 cm ) of O2 (Air Liquide, < 5 ppm total impurities) and CO (Air Liquide, N20) were injected every minutes in order to simulate lean and rich operating conditions as those encountered in an Otto engine coupled with a three-way catalytic converter. The Oxygen Storage Capacity (OSC) was calculated from the CO consumption after stabilization of the sample in alternate pulses condition. 

OSC measurements were carried out at 450°C in a chromatographic reactor previously described [9,10], according to a method developped by Yao and Yu Yao [3], A portion of the catalyst sample (0.02 to O.lg) was roughly crushed to 0.2-0.4 mm, inserted in a U-tube reactor and heated in a flow of He (30 cm min > impurities Oxygen Storage Capacity. 

When the oxygen storage capacity, i.e. the amount of oxygen available for the catalytic reactions, is experimentally measured, care must be taken to distinguish whether the... 

These conclusions are fully supported by the results in which the oxygen storage capacities (OSC) was measured for the samples. The values of OSC were determined by titration of the samples at 450°C with consequent pulses of CO which were introduced into the dry nitrogen flow passing through the sample bed in a quartz reactor till the formation of CO2 ceases. The results obtained in this series of determinations are given in Table 4. 

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