KCS

Generation of nanomorphic architectures having larger pores with microporous zeolite crystallinity is a great challenge in modern catalytic science and technology because such materials are expected to have high catalytic functions and selectivity. In this lecture, we focus on a synthetic strategy for the generation of nanomorphic zeolitic materials built with ultrathin frameworks of single-unit-cell thickness or even less. The strategy uses a surfactant molecule that possesses a zeolite-structure-directing functional group while the surfactant tails are organized to generate nanostructured architectures. The present strategy using a portion of molecule shows a striking difference from conventional zeolite structure-directing methods that use the entire part of small organic molecule. Depending on the detailed synthetic conditions, the surfactant molecules can generate a random assembly of 2-nm thick nanosheets, regular stacking of multilamellar nanosheets, nanospongy-like disordered network of nanocrystals, and other various types of hierarchically porous architectures. The large number of acid sites on the external surface of these materials renders them highly active for the catalytic conversion of large organic molecules, and the reduced crystal thickness facilitates diffusion and thereby dramatically suppresses catalyst deactivation through cokes deposition during reactions. It is expected that the present synthesis approach could be applied to various types of zeolites to improve their performance in a range of important catalytic applications such as the production of renewable energy and the development of green chemical processes.