Design and Synthesis of a Medium-Pore Aluminosilicate Zeolite SCM-53

Designing and synthesizing condensed, thermally stable zeolites by inverse sigma expansion of open-framework zeolites has been well achieved. However, creating thermally stable open-framework zeolites through sigma expansion of condensed-frameworks remains rare. Herein, we present the rational design and synthesis of a thermally stable medium-pore aluminosilicate zeolite SCM-53, which possesses a 2D 10 × 10-ring channel system. The framework of SCM-53 was theoretically predicted by sigma expansion of the framework of SCM-51, a small-pore aluminosilicate zeolite featuring a 2D 8 × 8-ring channel system prepared by calcination of the layered precursor SCM-50. SCM-53 was rationally synthesized by successive interlayer silylation and calcination treatments of SCM-50. The structure of SCM-53 was validated by powder X-ray diffraction (PXRD), scanning transmission electron microscopy (STEM), nuclear magnetic resonance (NMR) spectroscopy, and N₂ absorption measurement. Our results demonstrate that SCM-53 possesses accessible micropores (5.9 × 4.9 Å), an ultrathin nanosheet morphology (∼15 nm), and high thermal stability (up to 800 °C), suggesting its potential for adsorption and catalytic applications. We anticipate that sigma expansion offers a promising approach for the rational design and synthesis of targeted novel zeolite structures.