Vanadia Layers Supported on Titania — an FTIR and Raman Investigation

Abstract

Abstract The structure of monolayers and multilayers of V 2 O 5 supported on TiO 2 has been investigated by laser Raman spectroscopy. For the catalyst prepared by a single impregnation, disordered polymeric arrays of sixfold‐coordinated vanadium ions are detected. Second impregnation increases the number of V v centers anchored on the support but does not create new types of structure in detectable amounts. In the third impregnation step additional layers of V 2 O 5 are immobilized on top of the first layer, as evidenced by characteristic Raman bands at ∼996 cm −1 and 285 cm −1 . The intensity of these bands from higher layers increases after the fourth impregnation; at this stage the highest specific activity of the supported catalyst for selective catalytic reduction of NO is achieved. The above conclusions are confirmed by FTIR measurements, which reveal structural differences between the vanadia species immobilized in the first and subsequent layers.