The effect of TiO2 Oil the hydrodenitrogenation (HDN) performance of MoP/MCM-41 was investigated using quinoline and decahydroquinoline as the model molecules. The catalysts were characterized by XRD, CO chemisorption, TEM. TPR and pyridine FT-IR. Addition of TiO2 enhanced the C-N bond cleavage activity of MoP/MCM-41 but inhibited its dehydrogenation activity. A maximum HDN activity was observed when the TiO2 loading was 5 wt% The characterization results indicated that introduction of TiO2 did not affect the formation of Mol? phase The TiO2-containing catalysts possessed higher CO uptake than MoP/MCM-41, but no significant differences in the acid properties and particle size distributions were observed for all the catalysts. XPS results revealed a Surface enrichment of TiO2 Ti-containing catalysts and small amount of these surface TiO2 can be partially reduced to Tin+ (n < 4) It is suggested that these Tin+ (n < 4) species may be responsible for the promoting effect of TiO2 on the HDN performance of MoP/MCM-41 (C) 2009 Elsevier B.V. All rights reserved.