H2/CO2 separations in multicomponent metal-adeninate MOFs with multiple chemically distinct pore environments. Issue 47 (26th October 2020)

• Record Type: Journal Article
• Authors: Schulte, Zachary M.; Kwon, Yeon Hye; Han, Yi; Liu, Chong; Li, Lin; Yang, Yahui; Jarvi, Austin Gamble; Saxena, Sunil; Veser, Götz; Johnson, J. Karl; Rosi, Nathaniel L.
• Is Part Of: Chemical science. Volume 11:Issue 47(2020)
• Page Start: 12807
• Page End: 12815
• Publication Date: 2020-10-26
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/d0sc04979d
• Languages: English
• ISSNs: 2041-6520

Abstract

Abstract : Tailorable multicomponent MOFs and MOF membranes for efficient H2 /CO2 separation. Abstract : Metal–organic frameworks constructed from multiple (≥3) components often exhibit dramatically increased structural complexity compared to their 2 component (1 metal, 1 linker) counterparts, such as multiple chemically unique pore environments and a plurality of diverse molecular diffusion pathways. This inherent complexity can be advantageous for gas separation applications. Here, we report two isoreticular multicomponent MOFs, bMOF-200 (4 components; Cu, Zn, adeninate, pyrazolate) and bMOF-201 (3 components; Zn, adeninate, pyrazolate). We describe their structures, which contain 3 unique interconnected pore environments, and we use Kohn–Sham density functional theory (DFT) along with the climbing image nudged elastic band (CI-NEB) method to predict potential H2 /CO2 separation ability of bMOF-200. We examine the H2 /CO2 separation performance using both column breakthrough and membrane permeation studies. bMOF-200 membranes exhibit a H2 /CO2 separation factor of 7.9. The pore space of bMOF-201 is significantly different than bMOF-200, and one molecular diffusion pathway is occluded by coordinating charge-balancing formate and acetate anions. A consequence of this structural difference is reduced permeability to both H2 and CO2 and a significantly improved H2 /CO2 separation factor of 22.2 compared to bMOF-200, which makes bMOF-201 membranes competitive with some of the best performing MOF membranes in terms of H2 /CO2 separations.