Structural and Textural Characteristics of Zn-Containing ZSM-5 Zeolites and Application for the Selective Catalytic Reduction of NOx with NH3 at High Temperatures

Abstract

Zinc-containing MFI-type ZSM-5 zeolites were synthesized with ammonia coordinated zinc solution as zinc source, n-butyl amine as template and ZSM-5 as seeds by a facile one-step hydrothermal method, which exhibited outstanding performance for selective catalytic reduction NO with NH3 over a wide temperature range. The powder X-ray diffraction detected results showed that there was no other crystalline phase except for ZSM-5 phase and IR analysis suggested that the zinc had successfully incorporated into the zeolite framework was the vibration absorption peak at 1080 and 1230 cm−1 were broadened, which were assigned to asymmetric stretching of Si–O–Si. With the amount of zinc increases, big changes of morphologies, specific area and pore volume occurred which were collected by scanning electron microscope and Brunauer Emmett Teller Method. And the content of zinc species in the synthesized system was able to coordinate the growth size of the crystal. Furthermore, the addition of seeds would basically effectively prohibit the twin growth among these Zn-containing ZSM-5 crystals was firstly brought forward. Schematic diagrams of (A) Mono-dispersed ZSM-5 particles (B) Twin growth ZSM-5 particles.