A dynamic study of CO oxidation on supported platinum

Catalytic oxidation of CO on alumina-supported platinum was studied in a tubular isothermal reactor with applied concentration transients. A completely automated reactor system capable of switching frequencies as high as 0.2 Hz was constructed. Concentration cycling resulted in reaction rates that were much higher than the maximum rate achievable at steady-state operation. Mapping of the time-averaged carbon dioxide production rate in the time-period duty-fraction plane, resulted in a unique global maximum. We find that the maximum in rate occurs when the switching times are comparable to the characteristic time of the surface reaction. Results of our experiments also rule out significant contribution from the Eley-Rideal mechanism at the temperature range of this work (below 120°C).

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