Zeolites with stable, three-dimensionally interconnected large-pore channels, such as the industrially pivotal Y zeolite, are indispensable for the catalytic and separation processing of bulky molecules. Nevertheless, the synthesis of new frameworks beyond established types remains a persistent challenge. Here, we show that 2D-to-3D topotactic condensation, previously known to produce predominantly 1D/2D-channel or small/medium-pore 3D structures, affords a novel 3D large-pore high-silica zeolite. Through structure-guided design, a cyclohexyl-enriched organic structure-directing agent was developed to stabilize terminal bea building units, leading to a new 2D large-pore, high-silica precursor, JU-67. Calcination of JU-67 induced its topotactic conversion into a 3D large-pore zeolite, JU-68. This material possesses a unique anisotropic 12 × 12 × 12-ring channel system and a large supercage, which confers unique xylene adsorption and promising performance in the catalytic cracking of heavy oil, achieving a propylene yield higher than that of the industrial USY-based catalyst.
Gong et al. (Tue,) studied this question.