Insight into the better performance of Co than Pt on Ce-Sn catalyst for soot oxidation

In this study, a 3 %Co/Ce-Sn catalyst (T50 = 456 degrees C) exhibited much better performance than a noble 1 %Pt/CeSn catalyst (T50 = 510 degrees C) for soot oxidation. The 3 %Co/Ce-Sn catalyst also performed excellent poisoning resistances to H2O and SO2. Characterization results revealed that the introduction of Co induced more oxygen defects than Pt for the catalyst, which could be favorable to activating the surface chemisorbed oxygen to produce active oxygen species. Moreover, it was also identified that the active oxygen species govern the oxidation process of NO to NO2, which could then facilitate soot oxidation by a NO2-assisted mechanism. Our results provide significant understanding of the design of low-cost and high-performance catalyst for soot oxidation, and the obtained 3 %Co/Ce-Sn catalyst would be a promising candidate for the control of soot in diesel vehicles.