Developing Ultra-microporous Metal Organic Frameworks for Selective Sorption of CO2

Abstract

CO2 capture from flue gas is considered crucial because of CO2 being a greenhouse gas contributing substantially to global warming. Currently, materials like aqueous amine solutions, zeolites, activated carbons are being used to capture CO2 from large scale sources, but they require high regeneration energy and cost. Therefore, porous materials like Metal Organic Frameworks (MOFs) have recently attracted lot of attention mainly because of their tunable surface functionalities, pore size, low heat capacity etc. Very recently, for obtaining selective capture of specific gases ultra-microporous MOFs have been identified as a prime candidate. They are relatively cheap as they are formed from readily available small ligands. They are stable owing to small pores and limited void volumes. They offer high selectivity owing to their inherent molecular sieving ability and nano confined spaces lined with active functional groups. However, in many cases their capacities for gas molecules are not high. For example, for any useful CO2 capture applications a capacity of well over 3 mmol/g at STP is required.