CO₂ Capture by Hybrid Ultramicroporous TIFSIX‐3‐Ni under Humid Conditions Using Non‐Equilibrium Cycling

Abstract

Although pyrazine-linked hybrid ultramicroporous materials (HUMs, pore size < 7 Å) are benchmark physisorbents for trace carbon dioxide (CO 2 ) capture under dry conditions, their affinity for water (H 2 O) mitigates their carbon capture performance in humid conditions. Herein, we report on the co-adsorption of H 2 O and CO 2 by TIFSIX-3-Ni-a high CO 2 affinity HUM-and find that slow H 2 O sorption kinetics can enable CO 2 uptake and release using shortened adsorption cycles with retention of ca. 90 % of dry CO 2 uptake. Insight into co-adsorption is provided by in situ infrared spectroscopy and ab initio calculations. The binding sites and sorption mechanisms reveal that both CO 2 and H 2 O molecules occupy the same ultramicropore through favorable interactions between CO 2 and H 2 O at low water loading. An energetically favored water network displaces CO 2 molecules at higher loading. Our results offer bottom-up design principles and insight into co-adsorption of CO 2 and H 2 O that is likely to be relevant across the full spectrum of carbon capture sorbents to better understand and address the challenge posed by humidity to gas capture.

THD-C Sheet: A Novel Nonbenzenoid Carbon Allotrope with Tetra-, Hexa-, and Dodeca-Membered Rings

“…We find that the tube we have studied actually outperforms MOF-74 in several ways. For example, the presence of water is detrimental to coadsorbed species in MOF-74, as it preferentially adsorbs water molecules . In fact, water has the second strongest binding energy in MOF-74, the strongest being NH 3 .…”

“…For example, the presence of water is detrimental to coadsorbed species in MOF-74, as it preferentially adsorbs water molecules. 76 In fact, water has the second strongest binding energy in MOF-74, the strongest being NH 3 . 39 On the other hand, the tube offers a weaker interaction with water in comparison with CO 2 and the C 2 alkanes, depending on tube diameter.…”

A scalable robust microporous Al-MOF for post-combustion carbon capture

“…Fluorinated MOFs, such as SIFSIX and TIFSIX based MOFs or NbOFFIVE-1-Ni, are also considered as potential candidates for the post combustion capture due to their outstanding capacity and CO 2 /N 2 selectivity. [19][20][21][22] However, their long-term hydrolytic stability is in most cases limited while their large-scale production is still hampered with strong safety issues, due to the potential formation of HF. From the material cost point of view, aluminium based MOFs (Al-MOFs), if relying on cheap commercial polycarboxylic acids, and inexpensive Al metal source, whenever they can endow comparable CO 2 adsorption performance with CALF-20, stand themselves as promising candidates for CO 2 capture.…”