Enhancing carbon capture performance of polymeric membranes by incorporating hybrid two-dimensional boron nitride nanosheets and three-dimensional Prussian blue analogues nanofillers

Abstract

This study proposes a dual-filler mixed matrix membrane (MMM) strategy for CO₂/N₂ separation by incorporating two-dimensional (2D) hexagonal boron nitride (h-BN) nanosheets and three-dimensional (3D) Prussian blue analogue (NiHCF) particles into a polyethersulfone (PES) matrix. The incorporation of h-BN substantially enhanced the CO<inf>2</inf>/N<inf>2</inf> selectivity by introducing tortuous diffusion pathways that preferentially hindered N₂ transport. The subsequent addition of NiHCF, possessing strong CO₂ affinity, further increased selectivity while alleviating the permeability reduction typically associated with h-BN. Relative to the h-BN–only MMM (56 % lower than pristine PES), the dual-filler configuration reduces the CO₂ permeability loss by approximately 24 % (32 % lower than pristine PES) and maintains ∼1.5-fold increase in permeability and ∼1-fold increase in CO₂/N₂ selectivity. Overall, the optimized dual-filler MMM achieved a ∼3.4-fold improvement in CO₂/N₂ selectivity relative to pristine PES. These findings demonstrate that integrating structurally and functionally complementary fillers can effectively mitigate the permeability–selectivity trade-off, offering a promising strategy for high-performance CO₂ capture membranes. © 2025 Elsevier Ltd.