Insight into the Selection of the Post-Treatment Strategy for ZSM-5 Zeolites for the Improvement of Catalytic Stability in the Conversion of Methanol to Hydrocarbons

Desilication and dealumination are two common strategies to modify acidity and porosity of the ZSM-5 catalyst to enhance catalytic stability. However, the applicability of these strategies on the post treatment of specific ZSM-5 remains to be investigated. In this paper, a series of post-treated nano-ZSM-5 was prepared using single dealumination and desilication or combining two strategies and the effects of the silicon–aluminum structure, porosity, and acidity on catalytic stability of methanol to hydrocarbons (MTH) have been comparatively studied. This study found that for nano-ZSM-5 whose diffusion limitation is not the main cause of deactivation, dealumination should be considered to optimize acidity and silicon–aluminum structure on the surface for the improvement of catalytic stability, while for micro-ZSM-5, desilication should be first applied to construct mesopores to reduce diffusion constraints, followed by dealumination to optimize acidity and surface silicon–aluminum structure to improve the catalytic stability.