Industrial separations belong to some of the most energy-intensive technological processes because of the reliance on heat-consuming unit operations involving a phase change, such as distillation. Membrane technology promises large cuts to those energy needs; however, its progression is hindered as currently available membranes lack separation performance as well as chemical and mechanical stability. To address these challenges, carbon molecular sieves (CMSs) have long been suggested as promising candidates providing excellent and robust molecular separation performance. In this work, we introduce nanohybrid CMS membranes fabricated by pyrolyzing a polyimide of intrinsic microporosity (PIM-PI) precursor modified by vapor phase infiltration (VPI). In the VPI process, a metal-organic precursor, trimethylaluminum (TMA), first diffuses into the high free volume matrix of the PIM-PI to form a complex with its functional groups. Afterward, water vapor selectively and locally oxidizes the TMA to form nanodispersed Al₂O₃ within the PIM-PI matrix. Subsequent inert-atmosphere pyrolysis leads to the formation of Al₂O₃-doped, high-quality, thin-film composite CMS membranes with excellent molecular separation properties for a number of technologically important gas pairs, e.g. CO₂/CH₄ > 100, O₂/N₂ > 9. The introduction of VPI-doped hybrid CMS membranes allows obtaining extraordinary gas separation performance typical to high temperature undoped CMS at much lower pyrolysis temperatures. This presents significant advantages such as reduction of mechanical failure risk, wider spectrum of possible supports, and reduced fabrication complexity.

工业分离属于某些最耗能的技术过程，因为它依赖于涉及相变（例如蒸馏）的耗热单元操作。膜技术有望大幅削减这些能源需求。然而，由于目前可用的膜缺乏分离性能以及化学和机械稳定性，阻碍了它的发展。为了解决这些挑战，长期以来一直建议使用碳分子筛（CMS）作为有希望的候选物，它们可提供出色而强大的分子分离性能。在这项工作中，我们介绍了纳米复合CMS膜，该膜通过热解气相渗透（VPI）改性的本征微孔（PIM-PI）前体的聚酰亚胺制成。在VPI工艺中，金属有机前体三甲基铝（TMA）首先扩散到PIM-PI的高自由体积矩阵中，以与其官能团形成复合物。之后，水蒸气选择性地局部氧化TMA以形成纳米分散的Al在PIM-PI矩阵中为₂ O ₃。随后的惰性气氛热解导致形成Al ₂ O ₃掺杂的高质量薄膜复合CMS膜，该膜具有出色的分子分离性能，适用于许多重要的技术对气体，例如CO ₂ / CH ₄  > 100， O ₂ / N ₂ > 9.引入VPI掺杂的混合CMS膜可以在低得多的热解温度下获得非高温CMS特有的非凡的气体分离性能。这带来了显着的优势，例如降低了机械故障风险，可能的支撑范围更广以及制造复杂性降低。