Simultaneous improvement of accessibility and hydrophobicity in zeolites: water-tolerant nanosized crystals

Resumo

Diffusion limitations in zeolitic catalysts arise from the exclusive presence of micropores. Therefore, a strategy to enhance accessibility is to reduce the crystal size of zeolites, which shortens the diffusion path and makes catalytic sites more accessible. However, reducing the zeolite crystal size increases the density of silanol groups, affecting the material's hydrothermal stability. Thus, synthesizing nanosized zeolites presents a significant challenge: the high number of silanols makes the surface more hydrophilic, compromising the catalyst's performance in aqueous reactions. In this work, we aim to understand the influence of silanol groups and crystal size on zeolite stability and develop strategies to enhance the hydrothermal resistance of nanosized zeolites. Herein, MFI type zeolites were synthesized, with particle sizes between 1200 to 70 nm. Strategies for silanol healing will be developed to improve the water tolerance of nanosized zeolite.