Synthesis and characterization of a layered aluminosilicate NUD-11 and its transformation to a 3D stable zeolite

Abstract

Aluminosilicate zeolites are a well-known class of crystalline materials that have wide applications in various industrial fields due to their selective adsorption, acidic sites, and stable hydrothermal stability. Great efforts have been devoted to discovering new zeolite structures. As one of the effective methods, layered silicates have been used as precursors to produce stable zeolites through topotactic transformation. Herein, a new layered aluminosilicate, named NUD-11, was hydrothermally synthesized using N,N-dimethylbenzimidazolium as the structure directing agent (SDA). It was then converted into a stable crystalline zeolite by linking the interlayer Si–OH groups with a silylation agent, diethoxymethylsilane. Studies showed that the resulting NUD-11S consisted of alkylsilicate –O–Si(CH₃)₂–O– linkages between the adjacent layers to form interconnecting 10- and 12-membered ring channels. The calcined NUD-11S possessed micropores of 0.74 nm and 1.2 nm in diameter with a large specific surface area of 314 m² g⁻¹. The abundant microporosity would make NUD-11S useful as adsorbents or catalysts.