Structural and electronic double effects on S‐doping dendritic mesoporous CeFeW/DM catalyst for enhancing SO₂ tolerance in the low temperature NH₃‐SCR reaction

Abstract SO 2 poisoning severely impedes the development of Ce‐based catalysts in NH 3 ‐SCR process for nitrogen oxides elimination. S‐doping dendritic mesoporous (DM)‐structured CeFeW/DM catalyst has been carefully designed in this work and its tolerance to SO 2 has been effectively enhanced. The DM structure allowed metal oxides to be highly dispersed and generated Ce–O–Fe active pairs with enhancing redox ability via the efficient electron transfer between Ce 3+ + Fe 3+ ↔ Ce 4+ + Fe 2+ . Importantly, the opened center–radial pore channels not only facilitated rapid adsorption of NO and NH 3 , but also distinctly alleviated the problem of ammonium sulfate blocking the catalyst pores during the NH 3 ‐SCR process. Notably, S‐doping enhanced the surface acidity and inhibited the adsorption and oxidation of SO 2 effectively. Besides, density functional theory calculation revealed that S‐doping further perturbed the local electronic environment and formed an electron enrichment region around the Ce–O–Fe interface, which made SO 2 preferentially adsorbed on Fe sites, whereas NO was more inclined to be adsorbed on Ce sites. Therefore, the Ce active site was protected from SO 2 poisoning, enabling both L‐H and E‐R reaction pathways simultaneously occurring with smooth adsorption and activation of NO on CeFeW/DM. This study deeply reveals the coordination efforts between catalyst structure and electronic effects, which provided a new idea for designing highly efficient SO 2 ‐resistant Ce‐based catalysts for low temperature NH 3 ‐SCR reaction.