Synthesis of hierarchical nanocrystalline ZSM-5 with controlled particle size and mesoporosity

Development of new zeolite based materials is essential for a variety of applications in catalysis, separations, and medicine. Increasing the specific surface area and decreasing the micropore diffusion pathlength in zeolites are important factors for improving the performance of zeolites in catalytic applications and these factors can be optimized by decreasing the zeolite particle size. Creation of a hierarchical zeolite material that possesses both micro- and mesopores with very large surface areas and improved mass transport properties is an effective solution. In this study, a facile approach to a one step synthesis of nanocrystalline ZSM-5 zeolite from a single template system in 12–24 h at 140 °C and with high yield is presented. ZSM-5 zeolite crystals as small as 6 nm which form mesoporous aggregates of approximately 200 nm in diameter were synthesized using this method. The mesopore volume and size distribution showed a dependence on particle size such that smaller particles lead to higher mesopore volumes and narrower pore size distributions. The size of individual crystals, as well as mesopore surface area and pore volume can be controlled by adjusting the pH of the reaction mixture, as well as the hydrothermal treatment temperature and duration.

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► One step synthesis of nanocrystalline, mesoporous ZSM-5 zeolite from a single template.
► ZSM-5 crystals as small as 6 nm in mesoporous aggregates of approximately 200 nm in diameter.
► The size and mesoporosity were controlled by pH and the hydrothermal treatment conditions.