Promotional effect of potassium on soot oxidation activity and SO2-poisoning resistance of Cu/CeO2 catalyst

Potassium nitrate was incorporated to the Cu/CeO2 system to enhance the soot oxidation activity and sulfur-poisoning resistance. The Cu, K/CeO2 catalyst exhibited superior activity for soot oxidation with the lowest Tm at 313 and 359 °C under tight and loose contact modes, respectively. The CO–TPR curves demonstrated that the co-impregnation of copper and potassium effectively shifted the redox process of ceria to lower temperatures, contributing greatly to enhance soot oxidation activity. The IR spectra of SO2 poisoned catalysts implied partial transformation of KNO3 to K2SO4. The activity loss of the binary metal catalysts by SO2 poisoning was less than 70 °C thanks to remained KNO3.