Synthesis and catalytic applications of two-dimensional zeolites

Two-dimensional (2D) zeolites, enabled by their distinctive layered architectures, exhibit pronounced advantages in mass transport/diffusion and structural tunability, and have become a frontier in zeolite research. Centering on the main thread of synthesis strategies-catalytic applications-structural characterization, this review systematically summarizes the key mechanisms, structural tuning dimensions, and respective merits and limitations of both top-down strategies (swelling, delamination/exfoliation, intercalation/pillaring, and assembly-disassembly-organization-reassembly (ADOR)) and bottom-up strategies (one-pot synthesis, self-pillared architectures, and epitaxial growth). Representative reaction case studies are further used to elucidate structure–activity relationships of 2D zeolites in terms of enhanced mass transport, improved accessibility of active sites, stabilization of metal species, and extended catalytic lifetime. Meanwhile, we discuss how advanced characterization techniques, such as high-energy X-ray total scattering (HEXTS), four-dimensional scanning transmission electron microscopy (4D STEM), cryogenic transmission electron microscopy (cryo-TEM), and time-resolved spectroscopies, help reveal nucleation/growth processes and local structural evolution. Finally, key bottlenecks, including scalable, environmentally friendly, low-cost preparation and structural regenerability, are analyzed, and future directions are proposed for reproducible and scalable design and manufacturing routes for industrial implementation of 2D zeolites.