Cesium as a dual function promoter in Co/Ce-Sn catalyst for soot oxidation

Abstract In this study, a 10 %Cs/3 %Co/Ce0.5Sn0.5O2 catalyst with outstanding soot oxidation performance was developed, by doping Cs to 3 %Co/Ce0.5Sn0.5O2. Remarkably, doping Cs lowered the T50 of the catalyst by 163 °C under a H2O/O2/N2 atmosphere and loose contact. It was also noteworthy that the 10 %Cs/3 %Co/Ce0.5Sn0.5O2 catalyst exhibited excellent water and sulfur dioxide resistances. Characterizations indicated that the doping of Cs had dual functional effects on soot catalytic oxidation. On one hand, the introduction of Cs induced the formation of more oxygen defects, which was beneficial to the activation of surface chemisorbed oxygen. On the other hand, it also benefited the catalytic performance by increasing the mobility of the surface-active oxygen species, which favored the contact between soot and catalyst. Therefore, the alkali metal cesium was found to be an excellent promoter for soot catalytic oxidation, and the developed 10 %Cs/3 %Co/Ce0.5Sn0.5O2 catalyst is very promising for practical applications in diesel soot oxidation.