A series of lithium-based lean-burn NOx trap catalysts Pt/Li/TiO2-Al2O3 were prepared by sequential impregnation. The doping of TiO2 into the support Al2O3 significantly enhances the sulfur-resistance performance of the catalyst Pt/Li/Al2O3. On TiO2-Al2O3 mixed oxides, the Pt and lithium species are more highly dispersed, giving higher NOx storage capacity, as compared with those on Al2O3 and TiO2. In situ DRIFTS reveals that the NOx storage on Pt/Li/TiO2-Al2O3 mainly proceeds on -OLi sites forming bidentate nitrate species at 500 degrees C. The catalyst Pt/Li/TiO2-Al2O3 with 40% TiO2 in the support is the most promising one applicable to the lean-burn NOx abatement.