Fabrication and catalytic performance of highly stable multifunctional core-shell zeolite composites

Multifunctional Fe₃O₄@SiO₂-Au@silicalite-1 core-shell magnetic zeolite composites were fabricated by combining a series of sol-gel process and vapor-phase transfer of silicalite-1 zeolite nanocrystal-seeded silica shells. The obtained composite has high magnetization (32.00 emu/g), stably confined and active gold nanoparticles (ca. 15 nm), and a hierarchical silicalite-1 outer shell. The core-shell composite exhibits a high efficiency of magnetic separability, excellent catalytic performance, and reusability for the reduction of 4-nitrophenol with conversion of 98% in 12 min. Moreover, it preserves a good stability after a high-temperature hydrothermal treatment.