Effects of zinc incorporation on hierarchical ZSM-11 catalyst for methanol conversion

ABSTRACT: Hierarchical ZSM-11 and Zn-ZSM-11 catalysts were used in this study. The effects of two methods (direct synthesis and impregnation) of zinc incorporation on methanol conversion were investigated in a continuous-flow isotherm fixed-bed reactor. XRD, SEM, BET, FTIR, and XRF analytical results revealed that the introduction of zinc through direct synthesis generated new Brønsted acid sites that could tune the ratio of light olefins. The damage to the framework structure after zinc incorporation restrained the aromatization, dehydrogenation, and decomposition of methanol. The extent of this impact determined the degree of deactivation behaviors. Thus, the yield of propene and butene was enhanced through the direct synthesis method (2 % ZnZ11-C, 4 % ZnZ11-C), and the sample 4 % ZnZ11-C displayed a fast deactivation. GRAPHICAL ABSTRACT: [Image: see text]