Self‐Pillared Pentasil Zeolite Microspheres as Self‐Supported Catalysts With Enhanced Molecular Diffusion for Waste Plastic Upcycling

ABSTRACT Hierarchical and two‐dimensional zeolites often exhibit superior diffusion properties and catalytic performance unattainable with conventional three‐dimensional crystals, yet their practical deployment is limited by shaping with binders that compromise these structural advantages. Here we report the synthesis of self‐pillared pentasil (SPP) zeolite microspheres as self‐supported catalyst bodies built from nanosheets in a characteristic house‐of‐cards arrangement. Time‐resolved studies reveal that, in a dual‐template system containing tetrabutylphosphonium hydroxide (TBPOH) and ethylenediamine (EDA) as co‐structure‐directing agents, SPP zeolite nanosheets spontaneously assemble into microscale spheres during crystallization while developing their hierarchical architecture. This strategy is not limited to the pure‐silica composition but also enables the synthesis of aluminosilicate SPP microspheres with enriched Brønsted and Lewis acidity. Diffusion measurements, together with peak‐force quantitative nanomechanical mapping (PF‐QNM) and nanoindentation analyses, show that the SPP microspheres combine efficient molecular transport with appreciable mechanical robustness. As a proof of concept, we further demonstrate that the aluminosilicate SPP microspheres function as self‐supported and recyclable catalysts for polyethylene upcycling, which achieve high conversion, selective formation of liquid hydrocarbons, and excellent structural stability upon reuse. These findings provide a synthetic blueprint for self‐supporting structured zeolitic catalysts and highlight their broader potential in catalytic transformations involving bulky molecules.