NOx adsorption study over Pt-Ba/alumina catalysts: FT-IR and reactivity study

The NOx storage process over Ba/Al2O3 and Pt-Ba/Al2O3 NSR catalysts has been analyzed in this study by performing experiments at 350 °C with NO2 and NO/O2 mixtures using different complementary techniques (Transient Response Method, in situ FT-IR and DRIFT spectroscopies). The collected data suggest that over the Pt-Ba/Al2O3 catalyst the NOx storage process from NO/O2 mixtures occurs forming at first nitrite species, which progressively evolve to nitrates. In addition, a parallel nitrate formation via disproportionation of NO2 (formed upon NO oxidation) cannot be excluded.