Siberian Federal University

ZSM‑11 zeolite (Si/Al = 60) with high mesoporosity was synthesized by the steam‑assisted crystallization (SAC) method using tetrabutylammonium hydroxide (TBAOH) as the single structure- directing agent. For comparison, ZSM‑5 samples were synthesized under identical conditions using tetrapropylammonium hydroxide (TPAOH). The obtained samples were characterized by powder X‑ray diffraction to determine the phase composition, low‑temperature nitrogen adsorption/desorption to investigate textural properties, as well as scanning electron microscopy (SEM) and high‑resolution transmission electron microscopy (TEM) to study crystal morphology. XRD analysis showed that the samples obtained in the presence of TBAOH represent a pure phase of the MEL framework type zeolite. The low‑temperature nitrogen adsorption/desorption method demonstrated high mesoporosity of the samples (Vmeso = 0.8 cm3/g). SEM and TEM data indicate that the MEL sample synthesized with an aging step consists of uniform crystals with an average size of approximately 20 nm