On the activity and stability of Pt-K/Al2O3 LNT catalysts for diesel soot and NOx abatement

tDPNR Pt-K/Al2O3catalyst has been studied for the simultaneous removal of soot and NOx, in the presenceof both water and carbon dioxide. In particular, the effect of soot on the NOxstorage activity and onthe stability of Pt-K/Al2O3catalyst has been addressed. It has been found that: (i) the presence of sootdecreases the NOxstorage activity at any temperature in the range 250–350◦C; (ii) the stability of theadsorbed species is lower in the presence of soot; (iii) nitrates ad-species directly interact with soot andparticipate to the soot combustion; (iv) aged catalyst shows a lower storage capacity and a lower sootoxidation activity attributed to loss of K-active species.