Controlling Pore Shape and Size of Interpenetrated Anion-Pillared Ultramicroporous Materials Enables Molecular Sieving of CO₂ Combined with Ultrahigh Uptake Capacity

Abstract

The separation of carbon dioxide (CO) from hydrocarbons is a critical process for the production of clean energy and high-purity chemicals. Adsorption based on molecular sieving is an energy-saving separation process; however, most of molecular sieves with narrow and straight pore channels exhibit low CO uptake capacity. Here, we report that a twofold interpenetrated copper coordination network with a consecutive pocket-like pore structure, namely, SIFSIX-14-Cu-i (SIFSIX = hexafluorosilicate, 14 = 4,4'-azopyridine, i = interpenetrated) is a remarkable CO/CH molecular sieving adsorbent which completely blocks the larger CH molecule with unprecedented selectivity, whereas it has excellent CO uptake (172.7 cm/cm) under the ambient condition. The exceptional separation performance of SIFSIX-14-Cu-i is attributed to its unique pore shape and functional pore surface, which combine a contracted pore window (3.4 Å) and a relatively large pore cavity decorated with high density of inorganic anions. Dispersion-corrected density functional theory calculation and neutron powder diffraction were performed to understand the CO binding sites. The practical feasibility of SIFSIX-14-Cu-i for CO/CH mixtures separation was validated by experimental breakthrough tests. This study not only demonstrates the great potential of SIFSIX-14-Cu-i for CO separation but also provides important clues for other gas separations.

A Universal Porous Adsorbent for the Selective Capture of Carbon Dioxide

“…No further loss of CO2 was observed upon heating. Regenerating MUF-16 is simpler than typical adsorbents, 44 which is advantageous from energy efficiency and economic standpoints. The recyclability of MUF-16 was then established by more than 150 breakthrough-regeneration cycles for the separation of CO2/N2 (Figure 6c).…”

“…These were taken from either a direct statement of relevant details in the manuscript or were extracted from figures by a digitizer software. n/a | n/a | n/a n/a n/a n/a n/a n/a 25 ## mmen-Cu-BTTri 31 32 40 1 n/a | n/a | n/a n/a n/a n/a n/a n/a 190 UTSA-16 33 n/a 130 n/a SIFSIX-14-Cu-i 44 25 1 109 | n/a | 1.1 38 n/a 116.0 n/a n/a n/a mmen-Mg-dobdc 45 25 1 86.3 | 2.35 | n/a 71 c 36.7 n/a n/a n/a n/a…”

A highly stable metal-organic framework with well-matched pore cavity for efficient acetylene separation

“…In 2017, the first case of an ideal molecular sieve for C 2 H 2 /C 2 H 4 was found called SIFSIX-14-Cu-i (UTSA-200) 23 , which with the ultrafine tuning of its pore size (3.4Å), can not only effectively block C 2 H 4 but also adsorb high amounts of C 2 H 2 , thus setting up the benchmarks for both C 2 H 2 adsorption and C 2 H 2 /C 2 H 4 separation. However, UTSA-200 can also take up a large amount of CO 2 or C 3 H 4 at the same conditions, 24,25 which significantly restricts its separation performance for C 2 H 2 /CO 2 and other multicomponent gases mixtures.…”

Synthesis, Crystal Structure, and Properties of a New Coordination Polymer Built from N/O-Donor Mixed Ligands

“…Significantly, the surface area of CPs have great values ranging from 1000 to 10,000 m 2 /g, which have exceeded those of traditional porous materials, such as carbons and zeolites [11]. Moreover, CPs with functional modifications exhibit favorable gas adsorption, which are typically selective gas adsorption properties for CO 2 or alkanes, and they can potentially alleviate the greenhouse effect or be employed as carriers to store energy gas [13,14]. Meanwhile, polyazaheteroaromatic ligands, another series of N-donor ligands, including the imidazole, trizole and tetrazole, are also successfully used to construct coordination polymers [15][16][17].…”