A series of vanadia catalysts impregnated on titania pillared interlayered clays (Ti-PILCs) were prepared to identify the characteristics of vanadia on the surface of Ti-PILC for the selective catalytic reduction (SCR) of NO by NH3. V2O5/Ti-PILC exhibited superior performance as a novel SCR catalyst compared to conventional catalysts including V2O5/TiO2 and V2O5/Al2O3. NO removal activity over the supported vanadia catalyst is strongly influenced by the structure of vanadia species on the catalyst surface. The structure of vanadia species on various supports including TiO2, Al2O3, and SiO2 along with Ti-PILC has been examined by XRD, NMR and Raman analyses for the comparative study. Increasing the content of vanadia up to the monolayer coverage of the surface of Ti-PILC catalyst enhanced the ratio of the polymerized surface vanadia species to the isolated ones. These results are well correlated with TOF of vanadia on the catalyst surface for the reduction of NO by NH3. (C) 2004 Elsevier B.V. All rights reserved.