Global warming is one of the greatest threats to human civilisation. In particular, the increasing levels of anthropogenic carbon dioxide (CO2) emissions from fossil fuel combustion directly impact our environment causing the continuous rise of temperatures across the planet. Porous metal–organic frameworks (MOFs) or porous coordination polymers (PCPs) are amongst the most promising candidates for CO2 capture because their CO2 sorption capacity is directly tuneable as a function of the topology and chemical composition of the micropores. An emerging CO2 capture technology is based on the preparation of hybrid adsorbent materials which can be synthesised by confining solvents inside porous solid supports. It is believed that solvent confinement can promote gas solubility considerably over the corresponding macroscopic values and therefore CO2 capture enhancement. To the best of our knowledge, confined alcohol has never been used to enhance CO2 capture inside a PCP. To investigate this possibility, we have chosen a PCP material entitled InOF-1 composed of binuclear [In2(µ2-OH)] building blocks bridged by BPTC4- ligands. Furthermore, InOF-1 shows a 3-D framework structure with channel openings of approximately 7.5 Å (considering the van der Waals radii of the surface atoms). It also represents an ideal system for the study of the effect of confined alcohol on CO2 sequestration as the hydroxo (µ2-OH) functional groups are located inside the channels and can play a fundamental role in the solvent confinement effect. Herein, we report a 2.7-fold (kinetic experiment, 30 oC) or 3.6-fold (static experiment, 30 oC) increase in CO2 capture at one bar of CO2 upon filling 10% of the pore volume of InOF-1 by ethanol, together with the ethanol adsorption properties of InOF-1 and the direct visualisation of these ethanol molecules in ethanol saturated InOF-1 through single crystal X-ray diffraction experiments.

CO2 capture enhancement in InOF-1 via the bottleneck effect of confined ethanol

253rd National Meeting (2017)

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