Multiscale defect distribution in Beta zeolite unravelled by the combination of high-resolution electron microscopy and stepwise etching

Zeolites are crystalline microporous materials widely used in industrial applications, and their catalytic and adsorption performances are profoundly influenced by intrinsic defects. However, characterizing the multiscale distribution of such defects remains a major challenge, especially in zeolites with complex stacking faults such as Beta zeolite. Herein, we develop a strategy that integrates high-resolution transmission electron microscope (HRTEM) imaging with controlled stepwise etching to probe the defects distribution in Beta zeolite across multiple length scales. Experimental results suggest that the defective domains in individual Beta zeolite crystals are heterogeneously distributed and preferentially aligned along the c axis. HRTEM imaging further reveals a preferential localization of defects at specific T sites within zeolite framework. Moreover, the etching process simultaneously generates a hierarchical Beta zeolite, whose titanosilicate analogue exhibits superior catalytic performance in cyclohexene epoxidation reaction. This work provides new insights into recognizing the multiscale defects distribution in zeolites, which establishes a direct link between the defect engineering and enhanced catalytic performance.