Regeneration mechanism of a Lean NOx Trap (LNT) catalyst in the presence of NO investigated using isotope labelling techniques

► The regeneration mechanism of LNT has been investigated feeding isotopically labelled 15NO during the regeneration period. ► The regeneration mechanism proposed in the literature has been extended with additional routes for nitrogen formation. ► Regeneration in the presence of 15NO yields three N2 species, i.e. 14N2 (m/e = 28), 14N15N (m/e = 29) and 15N2 (m/e = 30). ► The extension of the different routes for N2 formation is affected by the hydrogen concentration in the regeneration step.