Getting insights into gas-phase sulfation effect on catalytic performance of praseodymium oxides in NH3-SCR of NO

Sulfation treatment has been widely used to promote the catalytic performance of ceria (CeO 2 ) based catalysts for the selective catalytic reduction of NO by NH 3 (NH 3 -SCR of NO). Praseodymium oxide (PrO x ), another commonly used rare earth material with similar structural properties as CeO 2 , also shows satisfactory redox properties due to the facile redox cycle of Pr 3+ ↔ Pr 4+ . In this work, gas phase sulfation treatment with varied duration was performed on PrO x at 200 °C, and the NH 3 -SCR activity of sulfated PrO x was evaluated. Based on the results of systematic characterizations (e.g., N 2 -physisorption, NH 3 oxidation , NO oxidation, in situ diffuse Fourier transform infrared spectroscopy), it is revealed that the catalytic performance of sulfated PrO x is highly dependent on the sulfation time (or the amount of sulfate species deposited on PrO x ), which has a significant impact on the competitive reaction between NH 3 oxidation and NH 3 -SCR of NO, thus determining the NH 3 -SCR activity of PrO x . This work provides new insight into tuning the interaction between PrO x surface and reactants (NO, NH 3 ) via sulfation treatment, which cam guide the design and application of PrO x based catalysts for NH 3 -SCR of NO in the future.