Incorporation of CO2 philic moieties into a TiO2 nanomembrane for preferential CO2 separation

Here we report a preferential CO2 separation membrane consisting of a nanometer-thick TiO2 layer incorporated with phtalic acid (PA) molecules on polydimethylsiloxane (PDMS) (PA@TiO2/PDMS). Incorporated PAs in TiO2 act as CO2-philic pores for preferential CO-(2) permeation over nitrogen. CO2 binding to the PA incorporated in TiO2 is confirmed by the density functional theory calculation (DFT). As a result, membranes with of PA@TiO2 layer demonstrated much higher selectivity to CO2 for mixed CO2/N-2 gas separation compared to a conventional PDMS membrane. The exceptional selectivity of the composite layer alone (>150) was estimated by a resistance model.