The role of lanthanum oxide in the formation of NO2 over Pt–Pb/Al2O3–La2O3 catalysts under lean-burn conditions

NO-SCR over Pt/Al2O3, Pt–Pb/Al2O3 and Pt–Pb/Al2O3–lanthanum catalysts was studied. In the reduction of NO with C3H8 over undoped catalysts high selectivity to N2O was obtained (36–31% mol), meanwhile in lanthanum doped catalysts the formation of N2O is inhibited and high amounts of NO2 appears (37–44% mol). The role of lanthanum in the formation of NO2 seems to be related to organo-nitrogen compounds traps, which after decomposition forms N2.