Study on the Preparation\nand Structural Properties\nof Core–Shell Hierarchical Pore Molecular Sieve Synthesized\nby a Silicon Coating Method

Core–shell molecular sieves exhibit excellent\nperformance\nin many catalytic processes due to their adjustable pore distribution\nand surface structure. This work developed a silicon coating method\nfor molecular sieves and explored the synthesis method of Y/amorphous-silica\ncomposite materials. The effects of ultrasound treatment, silicon\nsource addition amount, and template properties on the amorphous silica\nstructure and properties were determined through comparative experiments.\nThe optimal preparation conditions were obtained, achieving adjustable\nthickness of the molecular sieve shell. Subsequently, based on the\noptimal preparation conditions of Y/amorphous silica composite materials,\na ZSM-5/silicalite-1 composite molecular sieve with core–shell\nstructure was successfully synthesized, and the structural characteristics\nof the synthesized core–shell molecular sieve were comprehensively\nanalyzed. The amorphous silica core–shell composite materials\nprepared in this work achieved directional control of shell thickness\nand pore structure, providing a promising approach for the preparation\nof core–shell structures.