In Operando Investigation of the Gate Opening Process in Metal Organic Frameworks

Metal-organic frameworks (MOFs) are crystalline, modular, and porous materials used in catalysis, gas separation, and storage. Some MOFs exhibit "gate-opening" behavior, where structural changes upon gas exposure allow selective separation via preferential coordination, aiding in the recovery of gases like helium and argon. However, the mechanisms behind gate-opening, such as the initiation site and required gas penetration depth, remain unclear. This proposal aims to use Bragg coherent diffraction imaging (BCDI) to observe these structural changes in real-time. By varying nitrogen gas pressure around the gating threshold, we will visualize the crystal's transformations at each pressure step through diffraction peak reconstructions. This novel approach offers a detailed view of the gate-opening process beyond the reach of traditional techniques, providing insights to optimize MOF design for enhanced gas separation and industrial applications.