ZSM-48 zeolites with controllable mesopore formation: synthesis, characterization, and catalytic performance

Abstract

The creation of mesopore through desilication method is often followed by excessive silica dissolution, especially in high silica zeolite like ZSM-48, leading to crystal destruction. Herein, the mesopore was successfully generated through desilication method. Furthermore, the amount of mesopore was carefully controlled by adjusting Organic Structure Directing Agent (OSDA) contents in the zeolite framework via partial detemplation. Compared to their parents, the relative crystallinity remains the same for all the desilicated samples. Notably, the occluded OSDA within ZSM-48 may hold another role in desilication, which may affect the density and distribution of the acid site. Low-density polyethylene (LDPE) pyrolysis test exhibits improved catalytic performance for mesoporous samples, showed by the lower observed activation energy (Eobs). It further confirms the benefits of mesopore in enhancing the diffusion of the molecules.

Keywords

• Hierarchical zeolites
• Mesoporous zeolites
• Desilication
• ZSM-48
• Partial detemplation