A 0.5 wt.% Pt/TiO2 catalyst was prepared and used for the low-temperature selective catalytic reduction(SCR)of NO with C3H6 in the presence of excess oxygen.The effects of Pt loading and O2 concentration on Pt/TiO2 catalytic performance for low-temperature SCR were investigated.It was found that optimal Pt loading was 0.5 wt.% and excess O2 favored low-temperature SCR of NOx.The mechanism of low-temperature SCR of NO with C3H6 was investigated with respect to the behavior of adsorbed species over Pt/TiO2 at 150℃ using in situ DRIFTS.The results indicated that surface nitrosyl species(Ptδ+-NO and Ti3+-NO)and pt2+-CO are main reaction intermediates during the interactions of NO,C3H6 and O2.A simplified NO decomposition mechanism for the low-temperature SCR of NO with C3H6 was proposed.