Development of mesopore-containing CON-type zeolite with unique acidic and catalytic properties

Abstract

The development of the mesoporosity of zeolite frameworks is an effective method to enhance the catalytic performance in the methanol-to-olefin reaction. Mesopore-containing CON-type boroaluminosilicate zeolite was prepared by the alkaline treatment based on the post-synthetic hydrothermal treatment in NH₄OH solution containing cetyltrimethylammonium bromide. The change in the concentration of NH₄OH solution led to CON zeolites with different mesopore volumes. The effects of the NH₄OH concentration on the structural properties of the treated samples were investigated by XRD, N₂ adsorption, SEM, TEM, and ¹¹B, ²⁷Al, and ²⁹Si MAS NMR analyses. In addition, in situ FTIR with pyridine and 2,4,6-trimethylpyridine as probe molecules was applied to investigate the acidic properties. In the methanol-to-olefin (MTO) reaction, the mesopore-containing CON-type zeolite showed a longer catalytic life than the parent zeolite. The enhanced catalytic properties could be attributed to the dual effects of the alkaline treatment on the porosity and acidity modification.