Composite Porous Liquid for Recyclable Sequestration, Storage and In Situ Catalytic Conversion of Carbon Dioxide at Room Temperature.

Permanent pores combined with fluidity renders flow processability to porous liquids otherwise not seen in porous solids. Although porous liquids have been utilized for sequestration of different gases and their separation, there is still a dearth of studies for deploying in situ chemical reactions to convert adsorbed gases into utility chemicals. Here, we show the design and development of a new type of solvent-less and hybrid (meso-)porous liquid composite, which, as demonstrated for the first time, can be used for in situ carbon mineralization of adsorbed CO2 . The recyclable porous liquid composite comprising polymer-surfactant modified hollow silica nanorods and carbonic anhydrase enzyme not only sequesters (5.5 cm3  g-1 at 273 K and 1 atm) and stores CO2 but is also capable of driving an in situ enzymatic reaction for hydration of CO2 to HCO3 - ion, subsequently converting it to CaCO3 due to reaction with pre-dissolved Ca2+ . Light and electron microscopy combined with X-ray diffraction reveals the nucleation and growth of calcite and aragonite crystals. Moreover, the liquid-like property of the porous composite material can be harnessed by executing the same reaction via diffusion of complimentary Ca2+ and HCO3 - ions through different compartments separated by an interfacial channel. These studies provide a proof of concept of deploying chemical reactions within porous liquids for developing utility chemical from adsorbed molecules.