Mesoscale Reorganization\nof the Depolymerized Aluminosilicate\ninto Single-Crystalline Hierarchical Zeolite

Controllable synthesis of hierarchical zeolites from\nnatural aluminosilicate\nminerals is considered an efficient and eco-friendly approach for\nthe production of high-performance zeolites, but its synthesis mechanism\nis still obscure. Herein, we take the synthesis of a single-crystalline\nhierarchical NaA zeolite using submolten salt depolymerized kaolin\n(SMS-K) as the sole source of silicon and aluminum via a mesoscale\nreorganization strategy as an example to elucidate the reorganization\nprocess. Comprehensive morphological and structural analyses reveal\nthat sodium-rich voids in SMS-K facilitate concurrent assembly both\nwithin the interior and at the interface of the amorphous gel, leading\nto the formation of numerous nanoparticles with short-range order\nwhich assemble into single-crystal nanocube NaA zeolites with intracrystalline\nmesopores. By harnessing confinement effects, SMS-K modulates the\ngrowth of nanoparticle sizes and enhances the intimate interconnection\nof nanocubes, thereby yielding NaA zeolite aggregates that exhibit\n hierarchical porosity, encompassing micro-, meso-, and macropores.\nThis study offers the potential for designing and precisely controlling\nthe fabrication of hierarchical zeolites derived from natural minerals.