Highly selective separation of alkenes/alkanes at ambient conditions is crucial yet challenging in the petrochemical industry due to their similar physical properties and molecular sizes. The development of carbon adsorbents that possess a molecular sieve functionality is desirable. In this study, we focus on elucidating the effect of carbonaceous nanodomain evolution on the pore sizes for the selective sieving separation of alkenes/alkanes using sucrose-based carbon molecular sieves (SUC-x). Results show that the carbonaceous nanodomains evolved gradually toward a more orderly graphitic layer structure at elevated temperatures, promoting the shrinkage of ultramicropores at the subangstrom scale. SUC-900 exhibits the C₃H₆/C₃H₈ molecular sieving performance with a high C₃H₆ uptake of 2.0 mmol/g at 1.0 bar and 298 K and negligible C₃H₈ adsorption, achieving a molecular recognition precision of 0.4 Å. The breakthrough experiments further confirm the efficient separation of the C₃H₆/C₃H₈ mixture dynamically in the fixed bed packed with SUC-900. This study provides a significant guideline for the precise tuning of ultramicropore sizes in carbons by manipulating structural nanodomains, facilitating the design of diverse carbon materials for gas separation applications.

中文翻译：

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碳材料结构域演化对烯烃与烷烃选择性分离的影响


由于烯烃/烷烃具有相似的物理性质和分子尺寸，在环境条件下高度选择性分离烯烃/烷烃在石化行业中至关重要但也具有挑战性。开发具有分子筛功能的碳吸附剂是令人期望的。在这项研究中，我们重点阐明碳纳米域演化对使用蔗糖基碳分子筛（SUC-x）选择性筛分分离烯烃/烷烃的孔径的影响。结果表明，在高温下，碳质纳米域逐渐演化为更有序的石墨层结构，促进亚埃尺度超微孔的收缩。 SUC-900表现出C ₃ H ₆ /C ₃ H ₈ 分子筛性能以及高C ₃ 在 1.0 bar 和 298 K 下吸收 2.0 mmol/g，C ₃ H ₈ 吸附可忽略不计，实现 0.4 Å 的分子识别精度。突破性实验进一步证实了C ₃ H ₆ /C ₃ H ₈ 混合物在固定床填料中的动态高效分离与SUC-900。这项研究为通过操纵结构纳米域来精确调节碳中超微孔尺寸提供了重要指导，促进了用于气体分离应用的多种碳材料的设计。