Influence of Hydrothermal Treatment on the Interaction of Active Components and Following COS + CS ₂ Sulfation of Ce _0.5 Fe _0.5 O _<i>x</i> ‐CP Catalyst for NH ₃ ‐SCR Reaction

ABSTRACT Herein, the methods of co‐precipitation and hydrothermal treatment were proposed to regulate the promotional effect of COS + CS 2 sulfation on the NH 3 ‐SCR activity of Ce 0.5 Fe 0.5 O x catalyst. The results indicated that the co‐precipitation method contributed to the formation of Ce‐Fe solid solution in Ce 0.5 Fe 0.5 O x ‐CP catalyst, but the further hydrothermal treatment depressed the incorporation of Fe 3+ into cubic fluorite CeO 2 , promoting the formation of Fe 2 O 3 crystals while decreasing the defective sites of catalyst. Furthermore, the different interaction of active components not only influenced the NH 3 ‐SCR activity of Ce 0.5 Fe 0.5 O x ‐CP and Ce 0.5 Fe 0.5 O x ‐HT catalysts but also regulated the sulfation of COS + CS 2 on the catalysts surface. The further hydrothermal treatment decreased the concentration of iron species but increased the concentration of cerium species on the Ce 0.5 Fe 0.5 O x ‐CP catalyst surface. COS + CS 2 sulfation increased the surface Ce 3+ /(Ce 3+ +Ce 4+ ) and Fe 2+ /(Fe 3+ +Fe 2+ ) molar ratios of Ce 0.5 Fe 0.5 O x ‐HT effectively but decreased the calculated corresponding values of Ce 0.5 Fe 0.5 O x ‐CP. Furthermore, Ce 0.5 Fe 0.5 O x ‐HT‐S exhibited larger deposited surface sulfate, stronger medium–strong acid sites, and more active oxygen than Ce 0.5 Fe 0.5 O x ‐CP‐S due to the better surface conversion of COS + CS 2 .