Absorption/desorption of NOx process on perovskites: impact of SO2 on the storage capacity of BaSnO3 and strategy to develop thioresistance

Abstract The formation of species when BaSnO 3 is exposed to SO 2 under a variety of conditions is reported and discussed. Direct contact with 25 ppm SO 2 during 15 cycles of Lean–Burn operation leads to the complete loss of NO x absorption capacity owing to the formation of stable and irreversible bulk-like sulphates identified by FT-IR (990, 1060, 1125 and 1190 cm −1 ) and TGA–MS. When both NO 2 and SO 2 are present, the competition between the formation of nitrate and sulphate favours the latter, leading eventually to deactivation. If the catalyst is pre-nitrated before exposure to SO 2 , the co-existence of nitrates and sulphates between 100 and 300°C is possible and improved sulphur tolerance is obtained.