(159k) Modification of 13X Zeolite Via Molecular Layer Deposition for Post Combustion CO2 Capture

Molecular layer deposition (MLD) is a technique where two or more self-limiting reagents are sequentially delivered as vapors to a material to fabricate thin coatings. Prior work has shown that MLD coatings can be fabricated onto 5A zeolite to gradually shrink the effective pore diameter via a “pore-misalignment” phenomenon to improve the size-based selectivity of the zeolite while retaining high capacity. In this work, 13X zeolite was modified via MLD and characterized for CO₂ capture properties under conditions relevant to post combustion CO₂ capture. By optimizing the number of MLD cycles, the MLD modified 13X was able to achieve simultaneous improvements in CO₂/N₂ selectivity and CO₂ working capacity. It was hypothesized that the large 13X cages allow for internal MLD in the 13X zeolite. This results in passivation of strongly adsorbing sites, allowing previously irreversible adsorption sites to be utilized for reversible CO₂ sorption. This simultaneous tuning of limiting pore diameter and internal surface chemistry may enable previously unobtainable levels of freedom in tailoring physical sorbents for specific gas separation processes.