Comparison of Pt-BaO/Al2O3 and Pt-CeO2/Al2O3 for NOx storage and reduction: Impact of cycling frequency

•NOx storage functionality is essential for lean NOx reduction with lean/rich cycling.•Ceria redox pathway only has a secondary effect on NOx conversion under excess O2.•Promotion by fast cycling is due to better usage of NOx and oxygen storage sites.•Excess O2 enhances or inhibits NOx reduction on Pt/CeO2/Al2O3 below or above 400 °C.•C3H6 enhances NOx reduction on Pt/CeO2/Al2O3 in stoichiometric case with fast cycling.