In situ DRIFTS study of the SCR reaction of NO with ammonia over a high loading (15% weight) vanadia-titania catalyst

The Selective Catalytic Reduction (SCR) of NO with ammonia over a high loading vanadia-titania catalyst has been studied by "in situ" Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS). In the reaction steady state a linear relationship between the NO conversion and the area of the 2 nu(V=O) IR band is found. This result suggests that V=O species are the active sites in the SCR reaction over vanadia-titania catalysts. On the other hand, although NH4+ is the only adsorbed NH3 species detected in reaction conditions, the catalyst activity does not correlate with their surface concentration.