Reactivity of titanosilicates-supported catalysts for the selective catalytic reduction of NO with NH3 Original Research Article

The zeolites with MEL structure were synthesized via the hydrothermal method and the zeolites-supported catalysts, such as Cu2+, Ga3+, Co3+, Ce2+ and VO2+/zeolites, were prepared by the incipient wetness impregnation. The structures of the synthesized zeolites were characterized by techniques of XRD, FT-IR, SIMS, 29Si and 27Al MAS NMR. The selective catalytic reduction (SCR) of NO by ammonia was carried out with a glass reactor under a downstream flow. The synthesized TS-2 showed no significant DeNOx activity, instead of catalyzing the ammonia oxidation at a high temperature. Furthermore, the catalytic activity of TS2 zeolite can be effectively modified and tuned up through incorporating second metal ion such as Fe3+, Co3+, and Al3+ into the framework (i.e., [Fe,Ti]Z11, [Co,Ti]Z11, and [Al,Ti]Z11). Among the synthesized bimetallosilicates, the [Fe,Ti]Z11 zeolite is the most active catalyst for the SCR DeNOx with ammonia; the NO conversion and the N2 yield reach around 80%. In addition, impregnating the metal ions on TS2 or bimetallosilicates is also a very effective way to improve the SCR DeNOx activity. Ga3+/[Fe40,Ti40]Z11 and Co3+/[Fe40,Ti40]Z11 are the most active catalysts and show a potential for the practical applications.