Targeted Dealumination via In Situ Activation of Persulfate in Size-Selective Zeolite Channels.

Selective modification of zeolite structure at specific sites is crucial for optimizing catalytic performance. Tailoring the framework aluminum (Al) siting within particular channels is highly desired but remains challenging. Here, we introduce a persulfate-based dealumination strategy that enables selective removal of Al atoms through in situ activation and zeolite size-selective features. By delivering persulfate molecules into the 12-ring channels of mordenite zeolite, the method employs mild thermal treatment to activate these molecules, releasing etching species that preferentially remove Al from the 12-ring channels while preserving Al sites in the 8-ring channels. Such selective dealumination enhances catalyst longevity while maintaining high catalytic activity in the dimethyl ether carbonylation reaction. The strategy's effectiveness is confirmed through a combination of advanced characterization techniques, including in situ synchrotron X-ray diffraction, in situ high-energy X-ray total scattering, and probe-assisted solid-state nuclear magnetic resonance. This pioneering approach opens new opportunities for designing tailor-made zeolite structures for advanced catalytic applications.