Quest for an Optimal Methane Hydrate Formation in the Pores of Hydrolytically Stable Metal–Organic Frameworks

• Published in: Journal of the American Chemical Society
• Main Authors: Cuadrado-Collados, Carlos, Mouchaham, Georges, Daemen, Luke, Cheng, Yongqiang, Ramirez-Cuesta, Anibal, Aggarwal, Himanshu, Missyul, Alexander, Eddaoudi, Mohamed, Belmabkhout, Youssef, Silvestre-Albero, Joaquin
• Other Authors: Universidad de Alicante, King Abdullah University of Science and Technology (KAUST), Oak Ridge National Laboratory Oak Ridge (ORNL), UT-Battelle, LLC, Spallation Neutron Source, UT-Battelle, LLC-UT-Battelle, LLC, Thermodynamics, FPMS
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2020
• Subjects: [CHIM]Chemical Sciences; Methane hydrate
• Online Access: https://hal.archives-ouvertes.fr/hal-03090519; https://hal.archives-ouvertes.fr/hal-03090519/document; https://hal.archives-ouvertes.fr/hal-03090519/file/2020_JACS_Preprint.pdf; https://doi.org/10.1021/jacs.0c01459

International audience Porous MOFs capable of storing relatively high amount of dry methane (CH 4) in adsorbed phase are largely explored, however solid CH 4 storage in confined pores of MOFs in the form of hydrates is yet to be discovered. Here we report a rational approach to form CH 4 hydrates by taking advantage of the optimal pore confinement in relatively narrow cavities of hydrolytically stable MOFs. Unprecedentedly, we were able to isolate methane hydrate (MH) nanocrystals with a sI structure encapsulated inside MOF pores with an optimal cavity dimension. It was found, that confined nanocrystals require cavities slightly larger than the unit cell crystal size of MHs (1.2 nm), as exemplified in the experimental case study performed on Cr-soc-MOF-1 vs smaller cavities of Y-shp-MOF-5. Under these conditions, the excess amount of methane stored in the pores of Cr-soc-MOF-1 in the form of MH was found to be ≈50% larger than the corresponding dry adsorbed amount at 10 MPa. More importantly, the pressure gradient driving the CH 4 storage/delivery process could be drastically reduced compared to the conventional CH 4 adsorbed phase storage on the dry Cr-soc-MOF-1 (≤3 MPa vs. 10 MPa)