Implanting Colloidal Nanoparticles into Single‐Crystalline Zeolites for Catalytic Dehydration

Abstract

The encapsulation of functional colloidal nanoparticles (100 nm) into single‐crystalline ZSM‐5 zeolites, aiming to create uniform core‐shell structures, is a highly sought‐after yet formidable objective due to significant lattice mismatch and distinct crystallization properties. In this study, we demonstrate the fabrication of a core‐shell structured single‐crystal zeolite encompassing an Fe3O4 colloidal core via a novel confinementstepwise crystallization methodology. By engineering a confined nanocavity, anchoring nucleation sites, and executing stepwise crystallization, we have successfully encapsulated colloidal nanoparticles (CN) within single‐crystal zeolites. These grafted sites, alongside the controlled crystallization process, compel the zeolite seed to nucleate and expand along the Fe3O4 colloidal nanoparticle surface, within a meticulously defined volume (1.5 × 107 ≤ V ≤ 1.3 × 108 nm3). Our strategy exhibits versatility and adaptability to an array of zeolites, including but not restricted to ZSM‐5, NaA, ZSM‐11, and TS‐1 with polycrystalline zeolite shell. We highlight the uniformly structured magnetic‐nucleus single‐crystalline zeolite, which displays pronounced superparamagnetism (14 emu/g) and robust acidity (~0.83 mmol/g). This innovative material has been effectively utilized in a magnetically stabilized bed (MSB) reactor for the dehydration of ethanol, delivering an exceptional conversion rate (98%), supreme ethylene selectivity (98%), and superior catalytic endurance (in excess of 100 hours).