High-Loading Hybrid Carbon Molecular Sieve Membranes with Engineered Particle Sizes for Enhanced CO2/CH4 Separation

The gas separation performance of hybrid carbon molecular sieve membranes is critically influenced by the particle size of the fillers. Herein, ZIF-8 crystals of different sizes (≈50 nm, ≈500 nm, and ≈1 µm) are used as fillers to synthesize a series of ZIF-8-derived-carbon hybrid carbon molecular sieve membranes with high filler loading. As the ZIF-8 crystal size increases from nanoscale to microscale, the CO 2 permeability of the resulting hybrid carbon molecular sieve membrane for a CO 2 /CH 4 binary mixture increases, reaching 9965 Barrer with a selectivity of 28.05. This trend highlights a clear correlation between filler size and gas separation performance of the hybrid carbon molecular sieve membranes. Microscale ZIF-8-derived-carbon offers synergistic advantages by providing abundant hierarchical pores for molecular sieving and continuous, long pathways for efficient gas transport, while preventing particle aggregation under high loading. Our finding provides valuable insights for the further development of high-performance hybrid carbon molecular sieve membranes.