Regeneration of SO2-poisoned diesel oxidation Pd/CeO2 catalyst

Ce(SO4)2 is formed on SO2 poisoned Pd/CeO2 catalyst, inducing a decrease in catalytic activity. And the activity just partially recovers after regeneration although Ce(SO4)2 is eliminated. The BET surface area decreases severely and the size of both Pd and CeO2 crystallites increases after regeneration. This is due to the decrease of PdO–CeO2 interaction by Ce(SO4)2 on sulfated samples and the hydrothermal effect of regeneration process.

► Partial regeneration occurs when Ce(SO4)2 is eliminated from SO2 poisoned Pd/CeO2.
► Regeneration induces sintering of Pd and CeO2 and decrease of the BET surface area.
► Interaction between Pd and CeO2 is weakened by Ce(SO4)2.
► The sintering of Pd and CeO2 is related to reduction of Pd–CeO2 interaction.