KINETICS OF THE MICROWAVE-HEATED CO OXIDATION REACTION OVER ALUMINA-SUPPORTED PD AND PT CATALYSTS

The kinetics of the CO oxidation reaction on Pt/Al2O3 as well as Pd/Al 2O3 have been measured in a packed bed reactor heated by microwave ene rgy. The reaction rate was also measured in an identical reactor that was heated via conventional means, Several methods of temperature meas urement were explored for the determination of catalyst temperature in the microwave heated reactor, Insertion of a thermocouple after the m icrowaves have been switched off provided the best method for temperat ure measurement in this study, However, large-scale temperature gradie nts must be eliminated before this method can provide accurate tempera ture measurements, After suitable modifications in our packed bed reac tor to eliminate nonisothermality, we found that the rate of reaction and the reaction kinetics (order of reaction) for the microwave heated CO oxidation reaction were comparable to those for the conventionally heated reactor. The CO oxidation reaction therefore serves as an in s itu probe of metal surface temperature, These observations suggest tha t the Pt and Pd crystallites in a supported catalyst are not significa ntly hotter than the alumina support in a microwave heated reactor. (C ) 1997 Academic Press.