Abstract: CeO2-based solid solutions (Ce0.7Zr0.3O2-δ, Ce0.7Pr0.3O2-δ, and Ce0.7Gd0.3O2-δ) were prepared using a sol-gel method. Catalytic behaviors for diesel soot combustion over the CeO2-based solid solutions and three typical supports (TiO2, SiO2, and Al2O3) and their KNO3 doped catalysts have been studied. It was found that the CeO2-based solid solution catalysts had nearly the same good catalytic activity as the 30% KNO3 doped TiO2, SiO2, and Al2O3 had. As the formation of the CeO2-based solid solutions can slow down the sintering process and form more active oxygen, which enhanced the reducibility and hence improved the catalytic combustion activity. As the intrinsic high activity of the CeO2-based solid solutions, the addition of the KNO3 did not have obvious effect on them, especially for Ce0.7Zr0.3O2-δ and Ce0.7Pr0.3O2-δ, while for TiO2, SiO2, and Al2O3, the addition of KNO3 could remarkably enhance the combustion activity.

Key words: CeO2-based solid solutions, Diesel, Soot, KNO3, Catalytic combustion activity