An Unprecedented Pillar‐Cage Fluorinated Hybrid Porous Framework with Highly Efficient Acetylene Storage and Separation

Abstract

Despite much intense investigation on the C2H2/CO2 separation, the trade‐off between the adsorption capacity and separation selectivity is still tricky. To overcome the dilemma, we have rationally synthesized an ultra‐stable fluorinated hybrid porous material SIFSIX‐Cu‐TPA with the ith‐d topology. Completely differing from the famous pillar‐layer fluorinated materials, SIFSIX‐Cu‐TPA possesses a unique pillar‐cage structure, in which the SiF62− anions cross‐link two adjacent metal nodes as pillars to stabilize the three‐dimensional framework constructed by icosahedral and tetrahedral cages. As anticipated, SIFSIX‐Cu‐TPA has high BET surface area (1330 m2 g−1) as well as high C2H2 uptake (185 cm3 g−1 at 298 K and 1 bar). At the same time, due to the obvious difference in the adsorption performance of CO2 and C2H2 especially in the low pressure area, SIFSIX‐Cu‐TPA also exhibits an excellent C2H2/CO2 separation performance (breakthrough time up to 68 min g−1 at 298 K and 1 bar).

Breaking the trade-off between selectivity and adsorption capacity for gas separation

“…S AC (1:1/2:1) values at 1 bar were thereby determined to be 10.0/9.4 ( SIFSIX-21-Cu ) > 9.5/9.0 ( NbOFFIVE-3-Cu ) > 8.3/8.1 ( TIFSIX-4-Cu ) > 7.8/7.8 ( SIFSIX-21-Ni ) > 7.6/7.4 ( TIFSIX-4-Ni ) > 6.0/5.9 ( NbOFFIVE-3-Ni ) ( Figures S45–S50 ). As presented in Table S1 , under relevant partial pressures, S AC for the six HUMs studied in this contribution were found to be comparable to leading C 2 H 2 -capture sorbents such as SIFSIX-Cu-TPA (5.3), 29 MUF-17 (6), 50 ZJU-60a (6.7), 51 FJU-22a (7.1), 33 TCuBr (9.5), 30 ZJUT-2a (10), 52 TIFSIX-2-Cu-i (10), 53 FJI-H8-Me (10.4), 28 and MIL-100(Fe) (12.5). 54 …”

“…26 To the best of our knowledge, only a few (20) have been experimentally studied for C 2 H 2 /CO 2 separation under dynamic conditions (e.g., dynamic column breakthrough [DCB] experiments, see Table S1 ) including recently reported benchmarks set by ATC-Cu , 27 FJI-H8-Me , 28 and SIFSIX-Cu-TPA . 29 For example, ATC-Cu was found to exhibit an ideal adsorbed solution theory (IAST) selectivity of 53.6 for 1:1 C 2 H 2 /CO 2 separation. 27 The need to study sorbent performances under dynamic conditions arises because calculation of separation performance from C 2 H 2 and CO 2 single-component isotherms tends to overestimate separation performance.…”

“…IAST and fixed-bed simulated breakthrough calculations are, therefore, indicative rather than confirmative. Our review of the literature reveals that C 2 H 2 /CO 2 separation selectivity ( α AC ) values for equimolar (v/v) mixtures have been experimentally measured for only 16 sorbents, most of which are classified as MOFs: SIFSIX-Cu-TPA , 29 TCuI , 30 TCuBr , 30 TCuCl , 30 JCM-1 , 31 NKMOF-1-Ni , 32 FJU-22a , 33 FJU-89a , 34 HOF-3 , 35 FJU-6-TATB , 36 SSNU-45 , 37 JXNU-5 , 38 FJU-36a , 39 FeNiM′MOF , 40 UTSA-74a , 41 and sql-16-Cu-NO 3 -α' . 42 Whereas these results are promising, they do not fully address the spectrum of performance parameters needed before a material can be considered for commercialization.…”

Cage‐Like Porous Materials with Simultaneous High C2H2Storage and Excellent C2H2/CO2Separation Performance

“…Usually, porous materials, which possess ultra‐microporous pores, have high selectivity but low adsorption capacity due to the low surface areas [6] . As we all know, the adsorption capacity also plays an important role in the separation time and efficiency [7] . In the past few years, many materials have been reported to increase the capacity of C 2 H 2 storage.…”

An Unprecedented Pillar‐Cage Fluorinated Hybrid Porous Framework with Highly Efficient Acetylene Storage and Separation

“…In addition, SIFSIX-Cu-TPA can maintain the integrality of the structure in the common solvents, such as CH 3 CN, DMF, and even 0.1 M HCl aqueous solution, which also have been demonstrated by the coincident PXRD patterns (Figure 2 a). More [29] Angewandte Chemie Zuschriften impressively, there is no loss of crystallinity after exposing SIFSIX-Cu-TPA to air for over 6 months or immersing SIFSIX-Cu-TPA in water for 1 month, which indicates that SIFSIX-Cu-TPA is much stable to water. On the other hand, the thermogravimetric analysis (TGA) shows that fullydesolvated SIFSIX-Cu-TPA has no obvious loss of weight with the temperature up to 200 8C in N 2 (Figure S2).…”