Abstract
Catalyst-loaded wall-flow type honeycomb is effective for reducing the level of carbon particle emissions from diesel engines. Pt-supported oxides were investigated for the oxidation and reduction of carbon particles accumulated in the wall-flow type honeycomb. The initiation temperature of combustion of carbon particles was the same for all samples. After the initiation, Pt-supported Ce composite oxides, such as Pt/Ce0.7Zr0.3O2 and Pt/Ce0.9Pr0.1O2, combusted carbon particles at lower temperatures than Pt-supported CeO2, Pt/CeO2. In particular, combustion occurred at the lowest temperature over Pt/Ce0.9Pr0.1O2 after air aging treatment at 1073 K. Pt/Ce0.9Pr0.1O2 released the highest amount of O2 from the oxide at low temperatures and the Pt surface readily oxidized adsorbed CO by O2 in the gaseous phase. Presumably these properties improved the combustion properties of carbon particles.
