Multitechnique study of the interaction of SO2 with alumina-supported SnO2catalysts for lean NOx abatement

This study deals with the physicochemical characterization of SO2-treated a lumina-supported tin dioxide surfaces as a function of the tin oxide loadin g. Three analysis techniques were used: Fourier transform infrared spectros copy (FTIR), XPS and adsorption calorimetry, The two types of spectroscopie s allowed the identification of the nature of the sulphur-containing specie s after SO2 adsorption. The determination of the quantities of adsorbed sul phur-containing species was made possible by adsorption calorimetry and XPS , At 353 K the SO2 uptake was minimum for 8 wt,% Sn and the major species w ere SO32-, When increasing the Sn Loading, the weakly adsorbed SO2 species vanished whereas the amounts of sulphite species increased. Above 12 wt,% S n, the presence of sulphate species increased, with a maximum for bulk SnO2 , After desorption at 673 K, the SO2 uptake was considerably decreased and each sample presented more SO42- than SO32- species, Copyright (C) 2000 Joh n Wiley & Sons, Ltd.