On the activity and stability of Pt-K/Al sub(2)O sub(3) LNT catalysts for diesel soot and NO sub(x) abatement

DPNR Pt-K/Al sub(2)O sub(3) catalyst has been studied for the simultaneous removal of soot and NO sub(x), in the presence of both water and carbon dioxide.-In particular, the effect of-soot on the-NO sub(x) storage activity and on the stability of Pt-K/Al sub(2)O sub(3) catalyst has been addressed. It has been found that: (i) the presence of soot decreases the NO sub(x) storage activity at any temperature in the range 250-350 [degrees]C; (ii) the stability of the adsorbed species is lower in the presence of soot; (iii) nitrates ad-species directly interact with soot and participate to the soot combustion; (iv) aged catalyst shows a lower storage capacity and a lower soot oxidation activity attributed to loss of K-active species.