Catalytic Performance of Aged Rh/CeO2-ZrO2 for NO-C3H6-O2 Reaction Under a Stoichiometric Condition

The activity of Rh/CeO2 for NO reduction by C3H6 was gradually deceased by mixing with ZrO2 until 68 mol%. Rh supported on CeO2-ZrO2 with higher OSC was found to show lower catalytic activity. High OSC of CeO2-ZrO2 would probably stabilize the surface of Rh in oxidized state, resulting in low activity and low efficiency of C3H6 utilization for NO reduction. In situ FT-IR spectroscopy suggested that mononitrosyl species such as Rh(NO)(delta-) and Rh(NO)(delta+) are reaction intermediates in the NO-C3H6-O-2 reaction over Rh/CeO2-ZrO2 catalysts.