Title : Plasma-assisted synthesis of nanostructured zeolites: Enhanced dissolution, crystallization and performance for ethanol conversion
Abstract:
This study presents a plasma-assisted synthesis strategy for fabricating nanostructured zeolites, focusing on enhancing crystallization kinetics, structural properties, and catalytic performance for ethanol conversion to ethylene. Interestingly, Plasma can generate the radicals, which facilitate homogeneous nucleation and influence growth kinetics by modifying surface energy and depositing reactive species onto precursor particles. Furthermore, plasma exposure can induce structural defects of the Si-O-Al linkages such as silanol nests (Si-OH), which enhance dissolution and repolymerization during crystallization, further accelerating the synthesis process. Herein, plasma pretreatment of amorphous precursors was employed prior to hydrothermal crystallization, resulting in improved solubilization of silicon and aluminum species via the generation of silanol nests and hydroxyl radicals (·OH). Comparative synthesis of ZSM-5, Beta, and FAU zeolites, with and without plasma activation, revealed significant reductions in crystallization time and improved textural and acidic properties in the plasma-treated samples. The properties of the as-prepared catalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), N2 adsorption-desorption technique (BET), attenuated total reflection Fourier transform Infrared spectroscopy (ATR-FTIR), and ammonia temperature-programmed desorption (NH3-TPD) and confirmed higher crystallinity, uniform Si/Al distribution, and increased mesoporosity in the plasma-assisted zeolites. Catalytic testing demonstrated that plasma-treated zeolites exhibited superior ethylene selectivity and ethanol catalytic performance. These findings highlight the potential of plasma-assisted synthesis as a green, scalable approach to accelerate zeolite fabrication and tune their nanostructural and catalytic properties.
