Carbon molecular sieve (CMS) membranes are attractive for energy-efficient gas separations. A challenge with the fabrication of a high-performance CMS membrane is fine-tuning its microstructure for precise and efficient separation. This necessitates a molecular-scale analysis to understand its microstructure–performance relationship. Herein, molecular simulations were performed to unravel the relationships between four similar-sized CMS matrices with different microstructural characteristics (e.g., chemical composition and micromorphology) and their gas transport properties. Results show that the disordered packing of carbon layers, leading to the formation of ultramicropore (2–7 Å), originates from stereoscopic sp³ hybridized carbon atoms rather than non-carbon (oxygen) atoms. The size-sieving ability of CMS depends positively on ultramicroporosity; the adsorption capacity is strengthened and then weakened with the increase of ultramicroporosity. Competitive effects are observed in binary-mixture transport, and it is expected that the separation performance can be optimized by a reasonable distribution of ultramicropores combined with the affinity of oxygen-containing species.

中文翻译：

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利用分子模拟揭示 CMS 膜微观结构与气体传输特性之间的关系


碳分子筛 （CMS） 膜对于节能气体分离很有吸引力。制造高性能 CMS 膜的一个挑战是微调其微观结构以实现精确和高效的分离。这需要进行分子尺度分析以了解其微观结构-性能关系。在此，进行了分子模拟以揭示具有不同微观结构特征 （例如化学成分和微形态） 的四个相似大小的 CMS 矩阵之间的关系及其气体传输特性。结果表明，碳层的无序堆积导致超微孔 （2-7 Å） 的形成，起源于立体 sp³ 杂化碳原子，而不是非碳（氧）原子。CMS 的尺寸筛分能力与超微孔隙率呈正相关;吸附能力随着超微孔隙率的增加而加强后减弱。在二元混合物传输中观察到竞争效应，预计通过超微孔的合理分布结合含氧物质的亲和力可以优化分离性能。