Synthesis of Zeolites via Dehydrative Condensation of Preorganized Composite Building Units

The synthesis of high-performance zeolites with precisely controlled structures has led to the development of high-efficiency industrial catalysts, adsorbents, and separation membranes. Consequently, intense research efforts have been devoted to the development of novel high-performance zeolites. Although most zeolites are synthesized via hydrothermal synthesis, the formation mechanism is unclear, and a reasonable design has not yet been realized. Herein, a novel method for the synthesis of zeolites involving the stacking of composite building units (CBUs) is introduced. Using a hydrogen-bonded inorganic framework as a preorganized CBU, the zeolite was prepared via dehydrative condensation reactions under acidic conditions. Crystallization occurred throughout this process, while the CBU structure was maintained, leading to a novel zeolite with an eight-membered ring. Notably, by using this synthetic method, a large-sized zeolite that can be analyzed by conventional single-crystal X-ray diffraction techniques was obtained. The single-crystal X-ray diffraction analysis in combination with optimum-bright-field–scanning-transmission-electron-microscopy measurements confirmed the formation of the zeolite framework. This novel method for the synthesis of zeolites involving the assembly of CBUs provides a new platform for the development of unprecedented high-performance zeolites with arbitrary pore structures and active species.