Sorption-Enhanced Mixed Matrix Membranes with Facilitated Hydrogen Transport for Hydrogen Purification and CO₂ Capture

Mixed matrix membranes (MMMs) comprising size-sieving fillers dispersed in polymers exhibit diffusivity selectivity and may surpass the upper bound for gas separation, but their performance is limited by defects at the polymer/filler interface. Herein, a fundamentally different approach employing a highly sorptive filler that is inherently less sensitive to interfacial defects is reported. Palladium nanoparticles with extremely high H₂ sorption are dispersed in polybenzimidazole at loadings near the percolation threshold, which increases both H₂ permeability and H₂/CO₂ selectivity. Performance of these MMMs surpasses the state-of-the-art upper bound for H₂/CO₂ separation with polymer-based membranes. The success of these sorption-enhanced MMMs for H₂/CO₂ separation may launch a new research paradigm that taps the enormous knowledge of affinities between gases and nanomaterials to design MMMs for a wide variety of gas separations.