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/N₂ gas separation compared to a conventional PDMS membrane. The exceptional selectivity of the composite layer alone (>150) was estimated by a resistance model.