Two-dimensional zeolites in catalysis: current state-of-the-art and perspectives

Two-dimensional (2D) zeolites with modifiable structures, can possess great advantages in catalysis compared to three-dimensional (3D) rigid ones. Three kinds of 2D zeolites, including traditional lamellar ones, 2D zeolites induced by oriented growth with specially designed structural-directing agents, and 2D intermediates derived from germanosilicates, are covered in this review. 2D zeolites derived catalysts with higher surface area, larger pore size or hierarchical pore system release the diffusion constrains and enhance the accessibility of active sites, but they may also exhibit different microenvironments to the traditional 3D zeolites. The present review focuses on the complex relationship among pore architectures, location of active sites and the catalytic properties by comparing the 2D zeolite catalysts to 3D ones in the reactions catalyzed by framework Al or other heteroatoms (Ti and Sn), such as alkylation, selective oxidation and isomerization reactions. Last but not least, the challenges for future progress on both the preparation and application of these 2D zeolite catalysts are addressed.