Promotional effect of WO3 on the formation of O-2(-) over V2O5/TiO2 catalyst for selective catalytic reduction of NO with NH3 was studied. The aim of this novel design was to investigate the role of tungsten species in electrons transfer over the ternary VWTi catalysts. Analysis by XRD, XPS, PL and EPR showed that WO3 species improved the electrons transfer of the catalysts to facilitate the formation of reduced V2O5 that was important to improve the formation of superoxide ions. This property was remarkably different from that of the VTi catalyst and it could contribute to a new understanding of the catalytic behavior of VWTi catalyst in low-temperature SCR processes. (C) 2013 Elsevier B.V. All rights reserved.