Bimetallic cluster-modified UTSA-16 in PDMS membranes for high-performance CO₂ capture

Background Excessive carbon dioxide (CO₂) emissions are a major driver of climate change and ecological degradation. Developing low-energy separation technologies with high efficiency is essential for mitigating CO₂ emissions. Mixed matrix membranes (MMMs), which integrate organic polymers and inorganic fillers, provide a promising route to combine permeability and selectivity for gas separation. Methods UTSA-16 crystals were synthesized as fillers for polydimethylsiloxane (PDMS)-based MMMs. The solvent ratio of ethanol to water was tuned to regulate crystal morphology and particle size. Additionally, bimetallic precursor ratios were varied to optimize CO₂ adsorption capacity. The resulting UTSA-16/PDMS MMMs were evaluated for CO₂ permeability, CO₂/N₂ selectivity, and structural compatibility at different filler loadings. Significant Findings The optimized bimetallic composition, Co0.5 Zn0.5 W75, exhibited superior CO₂ adsorption due to a favorable particle size distribution and reduced interfacial defects with PDMS. The corresponding MMM achieved a CO₂ permeability of 3737.3 ± 80.2 Barrer and a CO₂/N₂ selectivity of 15.90 ± 0.92, representing a 66% improvement over pure PDMS membranes. However, excessive filler loading caused particle agglomeration, which introduced defects and reduced separation efficiency. These findings highlight the potential of tailoring filler composition and loading to maximize the performance of MMMs in sustainable CO₂ capture.