Amine-functionalized porous solid sorbents are widely regarded as leading candidates for post-combustion CO2 capture. While mesoporous MCM-41 is a benchmark material due to its tunable mesopores, its poor hydrothermal stability limits industrial applications. Here, asymmetric TiO2 films fabricated via block copolymer self-assembly and non-solvent induced phase separation (SNIPS) offer a robust, tunable alternative. Compared to alternating gyroidal TiO2 controls, they exhibit improved processability and reduced amine usage while achieving equivalent loading. CO2 adsorption studies across varying temperatures, flow rates, concentrations, and poly(ethylenimine) (PEI) loadings reveal that the asymmetric sorbents consistently outperformed their gyroidal counterparts, achieving 2.5–3 times higher uptake. A composite kinetic model identified a three-stage mechanism, with the time scales and relative contributions of each stage strongly dependent on adsorbent morphology. These findings highlight how structural asymmetry—through a balance of enhanced mass transport and amine-accessible surface area—improves adsorption efficiency and overall adsorbent performance.