Abstract
? 2022 Elsevier B.V.A series of TiO2-supported MOx catalysts (M=V, W, Ce, Cu and S) were investigated for their SCR activity. In situ Raman spectroscopy indicated that the supported MOx phases were completely dispersed as surface sites on the TiO2 support. In situ IR revealed that surface VOx, WOx and SOx sites anchored at both CeOx/CuOx and TiO2 sites. The number of surface Lewis acid sites decreased with the addition of basic (CeOx/CuOx) and acidic (VOx/WOx) sites in all catalysts, and acidic SOx in the unpromoted and Ce-promoted catalysts. The surface VOx, WOx and SOx sites introduced surface Br?nsted acid sites. The redox promoters increased the NO conversion, but SOx impregnation inhibited their effect due to acid (SOx)-base (CeOx/CuOx) interactions. The SCR reaction was shown to efficiently proceed via either surface NH3* or NH4+* species, resolving the long-standing dispute on the involvement of these species in the SCR reaction.
NSTL
Elsevier