(581e) 2D Hierarchical Zeolites: Facile Synthesis and Catalysis Applications

Two-dimensional (2D) zeolites represent an emerging type of hierarchical nanoporous zeolite materials. They are often made from the 2D layered precursors that contain stacked sheets of one-to-two-unit cell or smaller thicknesses. The post-modification such as intercalation, exfoliation, pillaring can produce delaminated and pillared zeolite structures that contain hierarchical micro- and mesoporosity within and between adjacent nanosheet layers. The organic and/or inorganic pillars introduced during post-modifications enable the structural flexibility, compositional flexibility, and multi-functionality of 2D zeolites for various applications. In this presentation, I would like to introduce our recent work on advanced synthesis and catalysis studies of hierarchical 2D zeolite materials. We have developed a simple one-step dual template synthesis method to tailor the textural properties of the 2D zeolite materials. A vapor phase pillarization (VPP) process was invented to produce pillared zeolites from 2D layered zeolite structures. The VPP process has high efficiency of alkoxide usage in the intercalation step, requires less water addition in the hydrolysis step, does not require separation for product recovery, and generates no liquid waste. Implications of the tunable meso-/microporosity on the spatial distribution and catalytic performance of active sites in hierarchical 2D zeolite catalysts have been studied using organic chemical titration, bulk and surface composition analysis, and catalytic gas and liquid phase reactions. The ability to form hierarchical 2D zeolites with tunable meso-/microporosity and understanding of their catalytic behaviors form important basis to advance their performance in catalysis applications.