Extreme crystal thinning of MFI zeolites enhances C3+ olefin selectivity by suppressing channel-intersection residence of hydrocarbon intermediates

초록

High C3+ olefin yields accompanied by minimal production of ethylene and aromatics are desirable for maximizing jet-fuel selectivity in the methanol-to-jet process. In three-dimensional MFI zeolites with 10-membered ring pore structures, channel intersections provide enlarged void spaces that facilitate the formation of bulky aromatic species, leading to increase in aromatic-cycle propagation. Herein, we demonstrate that extreme crystal thinning of MFI zeolites effectively suppresses the contribution of channel intersections by reducing the residence time of hydrocarbon intermediates within these regions. MFI nanosheets with thicknesses of 4 and 10 nm were synthesized and evaluated in the methanol-to-olefins reaction. As the crystal thickness decreased, C3+ olefin selectivity increased markedly, accompanied by suppression of ethylene and aromatic formation. Notably, 4-nm-thick MFI nanosheets with a Si/Al ratio of 161 achieved C3+ olefin yields (81.4%) comparable to those of one-dimensional MRE zeolites (Si/Al = 181) (76.9%), yet with significantly improved catalyst stability. Molecular dynamics simulations revealed that crystal thinning restricts molecular residence at channel intersections and promotes transport along channel segments, thereby limiting intersection-mediated aromatic chemistry. © 2026

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