کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
62799 | 47656 | 2007 | 10 صفحه PDF | دانلود رایگان |
The oxygen storage capacity (OSC) of Ce0.67Zr0.33O2 catalysts were investigated with CO–He pulses at 500 °C and CO–O2 dynamic pulses at 300–700 °C after redox and hydrothermal treatments. BET, XRD, and EPR were used to study the effects of the pretreatment on the surface and bulk structures of the catalyst. The results show that during the CO–He pulses, migration of oxygen from the bulk to the surface becomes important. The rate of oxygen migration depends on the structure of the solid and the number of the oxygen vacancies in the lattice. The experiments with dynamic pulses of CO–O2 reveal that DOSC is closely related to the surface area of the samples of the same composition. However, at high temperatures, oxygen in the bulk also contributes to DOSC due to bulk-to-surface migration. A mechanism describing the reaction between the surface oxygen and CO and the oxygen migration process from the bulk to the surface is proposed.
Journal: Journal of Catalysis - Volume 248, Issue 2, 10 June 2007, Pages 258–267