MIL-101 Metal–Organic Framework Functionalized with Flexible l-Tyrosine Ligands for Enhanced Greenhouse Gas Capture

To address environmental challenges such as global warming, we have synthesized a series of l-tyrosine-modified MIL-101 materials (X% Tyr-MIL-101, X = 0, 3, 5, 7, 10, 13) via an amino-acid functionalization strategy for greenhouse-gas capture. BET measurements suggest that l-tyrosine partially substitutes H2BDC in a monocoordinated fashion, dramatically enhancing specific surface area; notably, 7% Tyr-MIL-101 achieves a record 2891 m2/g, compared to 1269 m2/g for the unmodified analogue. Comprehensive characterization by FTIR, pore-size distribution, PXRD, SEM and TG-DSC confirms successful integration of l-tyrosine into the MIL-101 framework, concomitant with pore expansion, augmented pore volume, improved crystallinity and morphology and retained thermal stability. Static adsorption studies reveal that 7% Tyr-MIL-101 adheres to a Langmuir monolayer mechanism for CO2, CH4, CF4, NF3, N2, SF6 and C2F6, and demonstrates excellent regenerability, delivering uptake increases of approximately 66%, 57%, 81%, 71%, 77%, 79% and 76%, respectively, relative to 0% Tyr-MIL-101. In dynamic breakthrough tests, 7% Tyr-MIL-101 exhibits separation factors of 30.9 (SF6/N2), 27.9 (C2F6/N2), 26.9 (CO2/N2), 7.5 (NF3/N2), 7.4 (CF4/N2) and 5.6 (CH4/N2), all exceeding their ideal single-component values, demonstrating exceptional selectivity. In summary, our novel monocoordinated, flexible-ligand modification yields 7% Tyr-MIL-101 with both high adsorption capacities and outstanding separation performance for multiple greenhouse gases, providing a robust experimental foundation for the development of next-generation greenhouse-gas capture and separation technologies.