Activation of Praseodymium Oxide Catalyst by Platinum Doping

Abstract

The effects of platinum doping of praseodymium oxide on its catalytic activity have been examined. X-ray diffraction analysis showed that the doped platinum was incorporated into the lattice of praseodymium oxide. The catalytic activity of the oxide for CO oxidation was highly enhanced by platinum doping, and the activity maximum appeared at 0.2% Pt. Temperature-programmed desorption analyses revealed that the platinum doping depressed both absorption and desorption of the lattice oxygen in the oxide catalyst, while it enhanced the activity for reduction of the lattice oxygen by CO. These two effects must result in the appearance of the activity maximum. Since the, product of CO oxidation, CO₂, was incorporated into praseodymium oxide below 330°C and the catalytic activity was depressed, by CO₂, the reaction temperature should be kept higher than 330°C.