Metal−Organic Frameworks Based on Double-Bond-Coupled Di-Isophthalate Linkers with High Hydrogen and Methane Uptakes

Abstract

Solvothermal reactions of Cu(NO 3 ) 2 with azoxybenzene-3,3′,5,5′-tetracarboxylic acid (H 4 aobtc) or transstilbene-3,3′,5,5′-tetracarboxylic acid (H 4 sbtc) give rise to two isostructural microporous metal-organic frameworks, Cu 2 (abtc)(H 2 O) 2 • 3DMA (PCN-10, abtc ) azobenzene-3,3′,5,5′-tetracarboxylate) and Cu 2 (sbtc)-(H 2 O) 2 • 3DMA (PCN-11, sbtc ) trans-stilbene-3,3′,5,5′-tetracarboxylate), respectively. Both PCN-10 and PCN-11 possess significant enduring porosity with Langmuir surface areas of 1779 and 2442 m 2 /g (corresponding to BET surface areas of 1407 or 1931 m 2 /g, respectively) and contain nanoscopic cages and coordinatively unsaturated metal centers. At 77 K, 760 Torr, the excess gravimetric (volumetric) hydrogen uptake of PCN-10 is 2.34 wt % (18.0 g/L) and that of PCN-11 can reach 2.55 wt % (19.1 g/L). Gas-adsorption studies also suggest that MOFs containing CdC double bonds are more favorable than those with NdN double bond in retaining enduring porosity after thermal activation, although NdN has slightly higher H 2 affinity. The excess gravimetric (volumetric) adsorption at 77 K saturates around 20 atm and reaches values of 4.33% (33.2 g/L) and 5.05% (37.8 g/L) for PCN-10 and PCN-11, respectively. In addition to its appreciable hydrogen uptake, PCN-11 has an excess methane uptake of 171 cm 3 (STP)/ cm 3 at 298 K and 35 bar, approaching the DOE target of 180 v(STP)/v for methane storage at ambient temperature. Thus, PCN-11 represents one of the few materials that is applicable to both hydrogen and methane storage applications.

A Microporous Copper Metal–Organic Framework with High H2 and CO2 Adsorption Capacity at Ambient Pressure

“…Mesoporous MOFs show high adsorption capacities for CH 4 , CO 2 , and H 2 at high pressures. [2,3,[7][8][9][10] To increase the uptake of H 2 and CO 2 by physisorption at ambient pressure, adsorbents with small micropores as well as high specific surface areas and micropore volumes are required. [11,12] Such microporous materials seem to be more appropriate for gas-mixture separation by physisorption than mesoporous materials.…”

“…cam.ac.uk/data_request/cif. In-soc-MOF [38] 2.60 PCN-12 [17,33,34] 3.05 PCN-12-Si [12] 2.60 UTSA-20 [35] 2.92 MOF-505 [17,33] 2.59 SNU-5 [33,34,36] 2.84 PCN-11 [8,16,33] 2.55 NOTT-103 [9] 2.63 CPO-27-Mg [37] 2.50 HKUST-1 [17,33] 2.54-2.70 MOF-5 [39] 1.32…”

Synthesis and Characterization of a new hybrid material (MOF-5/Mag-H+ ) based on a Metal-Organic Framework and a Proton Exchanged Montmorillonite Clay (Maghnite-H+) as catalytic support

“…MOFs offer potential applications in catalysis, ion exchange, separation and polymerization due to their extremely large surface area, diverse means available for functionalization and well-ordered porous structures with a various geometry : one-dimensional 1D (channels), two-dimensional 2D (layers) and three-dimensional 3D (networks) [2]. MOFs have also attracted considerable attention in the field of adsorption as a means of storage of fuel gases, such as hydrogen and methane in order to promote utilization of adsorbed natural gas (ANG), as well as trapping CO 2 which is a greenhouse gas [3][4][5].…”

“…However, for an industrially viable product to be formed, bridging the gap to scalable continuous processing is essential. Therefore, crystals of MOFs can be formed in a scalable solvothermal continuous process with a maximum space time yield of nearly 1000 kg.m- 3 .day -1 [12]. One of the most representative MOFs is MOF-5 [Zn 4 O(BDC) 3 , BDC].…”

“…Therefore, crystals of MOFs can be formed in a scalable solvothermal continuous process with a maximum space time yield of nearly 1000 kg.m- 3 .day -1 [12]. One of the most representative MOFs is MOF-5 [Zn 4 O(BDC) 3 , BDC]. It is a structure which is formed by groups of (Zn 4 O) 6 + and extended in a 3D network with BDC (1,4-benzenedicaroboxylic acid) to produce a simple cubic lattice, with BET surface area from 260 m 2 /g to 4400 m 2 /g and with good thermal stability up to 400°C [13].…”