Metal-incorporated zeolites are emerging as promising materials due to their enhanced catalytic properties relative to conventional aluminosilicates; however, optimizing their properties requires a deeper understanding of the complex crystallization mechanisms involved in heteroatom incorporation. The processes of zeolite nucleation and growth are largely elusive due in large part to the challenges of characterizing zeolite growth (notably the evolution and role of diverse precursors) in chemically diverse environments. Most zeolite studies to date have relied on ex situ techniques to examine zeolite synthesis. The complex media and conditions of zeolite synthesis have made in situ techniques more difficult. To this end, our group has pioneered the use of in situ high-temperature atomic force microscopy (AFM) to directly visualize zeolite surface growth at near-molecular level. Through this approach, we have demonstrated that zeolite crystallization primarily occurs through nonclassical pathways, such as particle attachment, with classical monomer-by-monomer growth contributing to a lesser extent.
In this presentation, we will share our recent findings on the crystallization of zinc-modified faujasite (FAU). While our previous work established that Zn incorporation enhances both the stability and catalytic performance of zeolite FAU, the mechanism underlying Zn-assisted FAU formation has been unclear. Here, we will discuss our study employing in situ AFM to investigate the inhibitory effects of zinc on FAU crystal growth and shed light on its role during synthesis. Additionally, we will describe recent advancements in demetallation strategies for various heteroatoms in zeolites with framework types that include *BEA, MFI, and CHA. The selective removal of metals can introduce framework defects and stabilize extra-framework species (e.g., metal active sites), offering new opportunities to tune physicochemical properties beyond those of the pristine crystalline materials.