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 π-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 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.