SO2 Poisoning Structures and the Effects on Pure and Mn Doped CeO2: A First Principles Investigation

SO x poisoning effects in environmental catalysis have long been recognized as a challenge in development of efficient catalysts for industrial applications. In this paper, a theoretic method combining density functional theory and standard thermodynamic data (enthalpy and entropy) was applied to investigate the SO 2 poisoning to pure and Mn doped CeO 2 as model catalysts in realistic temperature and pressure. Surface Ce(SO 4 ) 2 rather than Ce 2 (SO 4 ) 3 was identified to be the most stable poisoning structure on pure CeO 2 . The SO x poisoning to the catalysts could not be surmounted simply by heteroatom doping, since the introduction of Mn will enhance the thermal stability of the surface sulfate. The results also indicated that the Lewis acidity of the catalysts could be enhanced by slightly sulfating, which might make some positive effect on catalytic performances for the abatement of environmentally sensitive species including NH 3, NO, CO, and hydrocarbons.