Robust Metal–Triazolate Frameworks for CO₂ Capture from Flue Gas

Abstract

Construction of thermally and chemically robust metal−organic frameworks (MOFs) is highly desirable for postcombustion CO 2 capture from flue gas containing water vapor and other acidic gases. Here we report a strategy based on appending amino groups to the triazolate linkers of MOFs to achieve exceptional chemical stability against aqueous, acidic, and basic conditions. These MOFs exhibit not only CO 2 /N 2 thermodynamic adsorption selectivity as high as 120 but also CO 2 /H 2 O kinetic adsorption selectivity up to 70, featuring distinct adsorptive sites at the channel center for CO 2 and at the corner for H 2 O, respectively. The best performing MOF in this series features low regeneration energy, high CO 2 capture utility under humid conditions, and decent cycling performance for mimic flue gas.M etal−organic frameworks (MOFs) are prominent solid adsorbents that combine well-defined adsorptive sites, fine-tuned pore sizes, and decorated interior functionalities to achieve strong binding affinity, high selectivity, large capacity, and low regeneration energy for CO 2 capture. 1−3 However, with respect to practical postcombustion capture, concerns arise from the competitive adsorption of H 2 O against CO 2 4

Benchmark C2H2/CO2Separation in an Ultra‐Microporous Metal–Organic Framework via Copper(I)‐Alkynyl Chemistry

“…In recent years,p orous metal-organic frameworks (MOFs) have attracted immense attention as very promising adsorbents for various gas separations, [4] ranging from relatively simple ones such as CO 2 /N 2 [5] and CO 2 /CH 4 [6] to more complex and challenging ones such as alkyne/alkene [7] and olefin/paraffin [8] separation. Amongst diverse gas separations, C 2 H 2 /CO 2 separation is among the most challenging separation tasks because of their same kinetic diameter (3.3 ).…”

Sequential Solid‐State Transformations Involving Consecutive Rearrangements of Secondary Building Units in a Metal–Organic Framework (MOF)

“…At 1 atm, the selectivities of C 2 H 2 /CH 4 , CO 2 /CH 4 , and CO 2 /N 2 are calculated to be 19, 60, and 192 at 273 K, and 8, 37, and 12 140 at 298 K, respectively. Though the sorption capacity is somewhat small, it is worth to note that the remarkable selectivity of CO 2 /N 2 far exceeds those of many reported MOFs, such as ZnF(daTZ) (120), [26] UTSA-85a (62.5), [27] and TEPA-MIL-101 (40 wt %) (220). [28] Overall, the impressive adsorption selectivity indicates that the framework of UPC-601 can form stronger interactions with CO 2 and C 2 H 2 than CH 4 or N 2 , making it potential candidate for CO 2 capture from flue gas and natural gas purification.…”

Carbon dioxide adsorption based on porous materials

“…Azolate linkers, such as 1,2,4-triazolate (TZ), 1,2,3-triazolate (Tz), and imidazolate (IM) have been used to prepare robust MOFs. Shi et al 51 used robust isoreticular metal triazolate frameworks with excellent CO 2 adsorption under humid conditions. ZnF(TZ) and its isostructures are shown in Fig.…”

“…5 Graphical illustration for the framework construction of a robust isoreticular metal triazolate (Reproduced with permission from ref. 51 Copyright© 2020, American Chemical Society). dimensions, channel system dimensionality, or composition, which makes zeolites one of the attractive materials of CO 2 adsorption.…”