Mechanism of Ce promoting SO2 resistance of MnO x /γ-Al2O3: An experimental and DFT study

Various physico-chemical techniques and theoretical chemistry computations are used to obtain a deep insight into the mechanism of Ce improving SO2 resistance of the catalyst Mn0.4Ce (x) /Al2O3 (x stands for the molar ratio of Ce : Al). Theoretical computation with density functional theory (DFT) shows that Ce modification enhances the adsorption energy of SO2 adsorbed on Ce surrounding, resulting in the preferential adsorption of SO2 on Ce surrounding. It protects the surface Mn from SO2 poisoning, leading to a better SO2 resistance. FT-IR and TG results are in good accordance with DFT results. FT-IR results suggest that absorption peaks related to SO4 (2-) cannot be detected in Mn0.4Ce0.12/Al2O3. Moreover, TG results show that weight loss peaks due to sulfated MnO (x) decomposition disappears after Ce addition. Therefore, Ce modification inhibits sulfates formation on active components lead to a better resistance to SO2 of Mn0.4Ce0.12/Al2O3.