Utilization of Three-Dimensional Electron Diffraction for Structure Determination of Extra-Large-Pore Zeolites.

The development of extra-large-pore (ELP) zeolites is crucial for industries of petrochemical catalysis, notably in processes like diesel cracking and hydrocracking of multi-carbon hydrocarbon substrates. The catalytic performance and selectivity of these zeolites depend heavily on their specific porous structures, making precise structure determination highly essential for understanding their properties and functionalities. However, the complex structures of ELP zeolites pose significant challenges for characterization. Three-dimensional electron diffraction (3DED) has emerged as a leading technique for studying zeolites as it does not require large crystals or pure samples. This review provides an overview of the development and application of 3DED for elucidating ELP zeolite structures. It begins with a summary of zeolites and their structural determination methods, followed by a detailed discussion of the principles and benefits of 3DED, the ELP zeolites discovered to date, and the specific applications and findings by 3DED. Additionally, the review anticipates that combining 3DED with other advanced techniques will enhance the understanding of ELP zeolites, including aspects like heteroatom doping, host-guest interactions, framework flexibility, and detailed structural characterization. This integration is expected to lead to innovations in the development and application of ELP zeolites.