Quest for an optimal methane hydrates formation in the pores of hydrolytically stable MOFs

• Published in: Journal of the American Chemical Society
• Main Authors: Cuadrado-Collados, Carlos, Mouchaham, Georges, Daemen, Luke L., Cheng, Yongqiang, Ramirez-Cuesta, Anibal J., Aggarwal, Himanshu, Missyul, Alexander, Eddaoudi, Mohamed, Belmabkhout, Youssef, Silvestre-Albero, Joaquin
• Other Authors: Advanced Membranes and Porous Materials Research Center, Chemical Science Program, Functional Materials Design, Discovery and Development (FMD3), Physical Science and Engineering (PSE) Division, Laboratorio de Materiales Avanzados, Departamento de Química Inorgánica-IUMA, Universidad de Alicante, E-03690 San Vicente del Raspeig, Spain., Oak Ridge National Laboratory, Spallation Neutron Source, 1 Bethel Valley Road, Oak Ridge, USA., CELLS-ALBA Synchrotron, Cerdanyola del Vallés, Barcelona, Spain., Chemical and Biochemical Sciences. Green Process Engineering. Mohamed VI Polytechnic University, Lot 660 – Hay Moulay Rachid, 43150 Ben Guerir, Morocco.
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: American Chemical Society (ACS) 2020
• Subjects: Methane hydrate
• Online Access: http://hdl.handle.net/10754/664293; https://doi.org/10.1021/jacs.0c01459

Porous MOFs capable of storing relatively high amount of dry methane (CH4) in adsorbed phase are largely explored, however solid CH4 storage in confined pores of MOFs in the form of hydrates is yet to be discovered. Here we report a rational approach to form CH4 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 CH4 storage/delivery process could be drastically reduced compared to the conventional CH4 adsorbed phase storage on the dry Cr-soc-MOF-1 (≤3 MPa vs. 10 MPa) G.M, M.E and Y.B thank Aramco sponsored research fund (contract. 66600024505). We would like also to acknowledge the support by King Abdullah University of Science and Technology. J.S.A would like to acknowledge financial support from the MINECO (MAT2016-80285-p), Generalitat Valenciana (PROMETEOII/2014/004), Oak Ridge beam time availability (Project IPTS-20859.1) and Spanish ALBA synchrotron (Project 2020014008).