Amine‐Rich Nanoparticle Liquids Enabling Efficient and Durable CO ₂ Membrane Separation

Abstract Membrane separation has emerged as a sustainable solution to reduce CO ₂ emissions. However, it often struggles to achieve a balance between high CO ₂ selectivity and permeability, limiting its industrial applications. Herein, nanoparticle liquids are introduced to membrane separation to tackle this problem. An amine‐rich nanoparticle liquid is spread on the surface of the polydimethylsiloxane (PDMS) substrate to form an ultrathin facilitated transport layer. The high fluidity, strong substrate conformality, and excellent solvent dispersibility of the nanoparticle liquids lead to an exceptionally thin, smooth, and defect‐free amine‐rich facilitated transport layers on the PDMS substrate, thereby maximizing CO ₂ selectivity through reversible chemical interactions. Meanwhile, the PDMS substrate ensures rapid gas permeation. Thus‐produced membrane exhibits ultrapermeable (3208 GPU) and ultraselective (105.4) performance in CO ₂ /N ₂ separation, surpassing the Robeson 2008 upper bound. More importantly, the separation performances are maximized at elevated temperature, which is highly demanded in post‐combustion CO ₂ capture. This nanoparticle‐liquid‐based route provides new insights in the design of next‐generation membranes for gas separation, and holds significant potential for revolutionizing CO ₂ capture technologies.