Enhancing CO 2 separation stability of ceramic–carbonate hollow fiber membranes via coregulation of the support and salt

Abstract Ceramic–carbonate dual‐phase (CCDP) hollow fiber membranes show high potential for high‐temperature CO 2 separation due to high packing density and thin walls. However, a permeability–stability trade‐off exists: pore optimization boosts CO 2 flux but accelerates carbonate loss. Here, a synergistic strategy combining ceramic support optimization and molten salt modification is proposed. Porous GDC (Ce 0.8 Gd 0.2 O 2‐δ ) supports were used, and the effect of 5 wt% nano‐TiO 2 in carbonate was studied. GDC1450 support achieved optimal porosity and strength. The membrane attained a CO 2 permeation flux of 5.32 mL·min −1 ·cm −2 at 900°C, outperforming most reported CCDP membranes. However, during a 100 h test at 700°C, its flux dropped 76% due to carbonate loss. In contrast, the nano‐TiO 2 ‐modified membrane showed flux reduction <10%. Nano‐TiO 2 enhanced carbonate retention, suppressed leakage, and improved durability. Overall, this synergistic strategy offers a viable route to overcome the trade‐off and develop CCDP membranes with both high flux and long‐term stability.