Effect of Dopants Pr and La on the Catalytic Activity of Cerium Oxide for Soot Oxidation

Abstract

Abstract Effects of rare earth or transition metal doping on the activity of CeO2 to particulate matter oxidation were investigated, and it was found that a Ce–Pr–La–O mixed oxide demonstrates the lowest ignition temperature of carbon, as low as 550 K. Oxygen-temperature-programmed desorption measurements suggested that the amount of O2 desorbed from CeO2 increases with the substitution of Pr, and furthermore, La doping reduces the desorption temperature of the lattice oxygen. Even in the absence of oxygen, carbon oxidation occurs on Ce–Pr–La–O, and the ignition temperature of carbon is almost the same as the desorption temperature of the lattice oxygen. Doping of La and Pr into CeO2 has a positive impact on carbon oxidation because of this decreased desorption temperature of the lattice oxygen.