Engineering multifunctional MDPCs@MOFs via selective thermal etching integrates low-resistance transport with strong adsorption for enhanced CO2/N2 separation

Metal-organic frameworks (MOFs) based Mixed-matrix membranes (MMMs) still present challenges in overcoming the traditional trade-off between permeability and selectivity in gas separation. Functionality of MOFs demonstrates great potentials in overcoming this issue. In this study, hierarchically structured multifunctional C@Fe 2 O 3 @ZIF-8 was proposed to construct strong adsorbed and low-resistance transport pathways enabling high CO 2 sieving through a “selective thermal etching” strategy. Leveraging the thermal stability difference between MIL-88 A(Fe) and ZIF-8, the core undergoes selective pyrolysis while preserving the crystalline ZIF-8 shell. The ZIF-8 shell enhances CO 2 /N 2 separation while optimizing interfacial compatibility, whereas the porous carbon core provides mesoporous structures for enhanced gas transport and ultramicroporous regions for improved CO 2 adsorption. Meanwhile, paramagnetic Fe 2 O 3 in the core layer enables optimized distribution of C@Fe 2 O 3 @ZIF-8 within the Pebax matrix. The C@Fe 2 O 3 @ZIF-8/Pebax MMM exhibits 216.46 % and 65.12 % improvements in CO 2 permeability and CO 2 /N 2 selectivity, respectively, over the Pebax matrix, exceeding the 2019 McKeown upper bound. This study pioneers a novel approach for constructing advanced multicomponent materials with customizable hierarchical structures by synergistically integrating high-throughput carbon channeling with MOFs molecular sieving technology.