High and selective CO_2 uptake, H_2 storage and methanol sensing on the amine-decorated 12-connected MOF CAU-1

摘要

The amine-decorated microporous metal-organic framework CAU-1 was readily synthesized and activated using a home-made efficient protocol. It exhibited a high heat of adsorption for CO_2, high CO_2 uptake capacity, and an impressive selectivity for CO_2 over N_2. At 273 K and up to 1 arm, CO_2 uptake capacity can reach as much as 7.2 mmol g~(-1). Comparatively, the CH_4 and N_2 uptakes at 273 K and 1 arm were only 1.34 mmol g~(-1) and 0.37 mmol g~(-1), respectively. The CO_2/N_2 selectivity was 101:1 at 273 K. The isosteric heat of adsorption ((Q_(st)) for CO_2 was ～48 kJ mol~(-1) at the onset of adsorption, and it decreases to ～28 kJ mol~(-1) at higher CO_2 pressures. Furthermore, CAU-1 can adsorb 2.0 wt% and 4.0 wt% hydrogen at 77 K under 1 atm and 30 atm, respectively. The adsorption characteristics of CAU-1 for methanol investigated in situ with a quartz crystal microbalance (QCM), indicated that this particular MOF structure can be used as a highly sensitive sensor for methanol detection such as direct methanol fuel cells.