Improvement of loose contact diesel soot oxidation by synergic effects between metal oxides in K2O–V2O5/ZSM-5 catalysts

Diesel soot oxidation in loose contact with 15 wt.% CuO/, V2O5/, Fe2O3/ and K2O–V2O5/ZSM-5 catalysts at a ratio of 9:1 was studied. V2O5/ZSM-5 was the most active with a peak activity at 450 °C. Further improvement was achieved with the incorporation of 4.5 wt.% K2O, attributed to the mobility of potassium upon melting. Chemical interactions between the K2O and extra framework silicon resulted in potassium silicate formation. Sintering of oxides towards the end of the oxidation process resulted in a delay in the completion of soot oxidation.