A microporous metal–organic framework with both open metal and Lewis basic pyridyl sites for high C2H2 and CH4 storage at room temperature

Abstract

A new microporous metal-organic framework, Cu2(PDDI) (ZJU-5; H4PDDI = 5,5'-(pyridine-2,5-diyl)diisophthalic acid), was solvothermally synthesized and structurally characterized. With open metal sites, Lewis basic pyridyl sites and suitable pore space, the acetylene uptake in ZJU-5a reaches the highest value of 290 cm(3) g(-1) at 273 K and 1 bar. Furthermore, ZJU-5a exhibits high absolute methane storage of 190 cm(3) (STP) cm(-3) at 35 bar and 224 cm(3) (STP) cm(-3) at 60 bar at room temperature.

Microporous metal-organic frameworks with suitable pore spaces for acetylene storage and purification

“…Cu 2 TPTC-Me can reversibly adsorb 257 and 203 cm 3 g -1 acetylene at 1 bar at 273 K and 298 K respectively, and Cu 2 TPTC-OMe can reversibly adsorb 248 and 204 cm 3 g -1 acetylene under the same conditions (Figure 5andFigure S6). Cu 2 TPTC-OMe is the highest gravimetric acetylene storage capacity material ever reported up to now, and both MOFs are higher than reported MOFs(Table 1): Cu 2 (EBTC) (160 cm 3 g -1 )[42], MnMOF-74 (168 cm 3 g -1 )[43], NOTT-101 (184 cm 3 g -1 )[6], MgMOF-74 (184 cm 3 g -1 )[43], ZJU-5a (193 cm 3 g -1 )[26], CoMOF-74 (197 cm 3 g -1 )[43], HKUST-1 (201 cm 3 g -1 )[37] at room temperature and…”

“…By immobilizing specific sites, such as open metal sites [23,24] and Lewis acidic and basic sites [25,26] into the frameworks, either high acetylene storage capacity or separation capacity has been reached in dozens of MOFs, but there are a few MOFs which exhibit both high acetylene storage capacity and separation capacity at the same time [27,28]. As for acetylene separation, optimization of both separation selectivity (mainly determined by the functional sites and size exclusive effect) and storage capacity (mainly determined by the gas storage capacities) is very important and still a challenge for researchers now.…”

“…As well-known, the MOFs with open metal sites usually exhibit high-performance for acetylene storage[23,24,26]. Both Cu 2 TPTC-Me and Cu 2 TPTC-OMe possess a large amount of open metal sites (~3.3 mmol g -1 ) to absorb acetylene molecules.…”

A novel metal-organic framework for high storage and separation of acetylene at room temperature

“…The various factors such as pore spaces/structure (pore size and pore shape), framework densities and open metal sites have been proved to impact on the performance of MOFs materials for gas storage and separation [11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29]. HKUST-1 with high density open Cu 2 þ sites exhibits an exceptionally high gravimetric acetylene storage capacity of 201 cm 3 (STP)/g at room temperature and atmospheric pressure [30].…”

“…The open metal sites can be straightforwardly generated through removing coordinative water or solvent molecules, followed by the vacuum activation and/or in situ thermal. The considerable researches have testified that NbO-type series of MOFs constructed from copper paddle-wheel Cu 2 (COO) 4 cluster and a variety of tetra-carboxylates show attractive application prospects in the field of acetylene storage and separation due to the open Cu 2 þ sites and suitable pore sizes [14][15][16][17][18][19][20][21][22][23][24][25][26]. Herein, we report a novel NbO-type metal-organic framework [Cu 2 (L)(H 2 O) 2 ]•(DMF) 6 Á (H 2 O) 2 (ZJU-10, ZJU ¼ Zhejiang University; DMF ¼N,N-dimethylformamide) constructs from the tetracarboxylate ligand H 4 L (Scheme 1) (H 4 L ¼2′-hydroxy-[1,1′:4′,1″-terphenyl]-3,3″,5,5″-tetracarboxylic acid).…”