<p>A polymer electrolyte membrane based on cellulose, 2-hydroxyethyl ether, and incorporating silver tetrafluoroborate (AgBF₄) and aluminum nitrate (Al(NO₃)₃) was designed to achieve enhanced CO₂ separation performance. Utilizing a facilitated transport mechanism, silver ions (Ag⁺) embedded within the membrane serve as selective carriers by forming reversible <i>π</i>-complexes with CO₂ molecules, substantially increasing their solubility and permeability. Experimental results demonstrated that the optimized membrane achieved remarkable CO₂ permeance of 1.3 GPU and a CO₂/N₂ selectivity of 131, underscoring its suitability for advanced gas separation processes. Scanning electron microscopy analysis revealed a selective layer thickness of approximately 5.51&#xa0;µm, an essential parameter for efficient gas transport. UV–Vis spectroscopy provided further confirmation of the stabilization of Ag⁺ ions by aluminum salts, effectively preventing their reduction into silver nanoparticles, thereby preserving their functionality as efficient CO₂ transport carriers. Fourier-transform infrared (FT-IR) spectroscopy analysis illustrated pronounced interactions between AgBF₄ and the ether functional groups of the polymer, evidenced by characteristic spectral shifts indicative of electron donation from ether oxygen atoms to Ag⁺ ions. The addition of Al(NO₃)₃ was found to significantly influence polymer free volume and ionic coordination environments, further facilitating effective CO₂ transport.</p>