Core–shell zeolite Y with ant-nest like hollow interior constructed by amino acids and enhanced catalytic activity†
Core–shell zeolite Y containing an ant-nest like hollow interior has been synthesized in the presence of natural amino acids. Time-resolved characterization of zeolite samples revealed the gradual development of three-dimensionally interconnected mesoporous channels via an intermediate stage of spatially aligned cavities in the core, which did not follow either a classical or a reversed crystal growth route. Comparative experiments suggested coordinative construction actions of amino acids, the interpenetration of which into the internal weak points of the aluminosilicate framework takes place simultaneously with zeolite crystallization. At the point of complete zeolite growth, amino acids in aggregated domains begin disassembling the zeolite interior forming a network of channels while maintaining the external zeolite shell thickness of 165 nm and morphologically similar to conventional faujasite. The core–shell zeolite Y samples exhibit superior crystallinity and enhanced catalytic activity for Friedel–Crafts benzylation of toluene.