Oscillations during CO oxidation over supported metal catalysts II. Effects of reactor operating conditions on oscillatory behavior for a (Pt-Pd)/Al2O3 catalyst
1984; Elsevier BV; Volume: 88; Issue: 2 Linguagem: Inglês
10.1016/0021-9517(84)90011-3
ISSN1090-2694
Autores Tópico(s)Catalysts for Methane Reforming
ResumoThe oscillatory behavior occurring during CO oxidation over a (PtPd)γ-Al2O3 catalyst was studied in an isothermal recycle reactor. The effects of recycle ratio (0–50), gas phase temperature (373–423 K), feed composition (0.053–0.43 mole% CO, 50–99% O2), feed flow rate (78–445 μmol/s), and reactor pressure (0.1–0.2 MPa) were examined. Care was taken to ensure that the catalytic activity remained constant throughout the investigation. The results indicate that oscillations are caused by changes in the rate controlling step coupled with heating of the metal crystallites to temperatures above those of the support and gas phase. It is proposed that the rate controlling step changes from oxygen adsorption to surface reaction followed by rapid burn-off (ignition) of adsorbed CO and oxygen.
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