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<p>Carbon membranes yielding high selectivity as well as high permeance are attractive to advance the membrane-based gas separation. Herein, we report ultrathin carbon membranes (UCMs) which deliver enhanced gas separation performance through oxygen-modulated pyrolysis of poly(4-vinylpyridine) precursor. We show that O<sub>2</sub> in pyrolysis environment, transforms the otherwise uniform carbon network featuring a ~ 3.9 Å characteristic interlayer spacing into disrupted UCMs (d-UCMs). These d-UCMs possess a multimodal ultramicroporous structure characterized by distinct d-spacings of ~3.4 Å, 3.9 Å, and 5.5 Å. This optimized distribution of free volume in a 10-nm-thick membrane enables a record combination of H<sub>2</sub> permeance exceeding 10,000 gas permeation units (GPUs) and H<sub>2</sub>/N<sub>2</sub> mixture selectivity surpassing 200. Meanwhile, d-UCM exhibits physical and thermal stability, showing no aging over 7 days of elevated temperature permeance testing, which overcomes the common issue of rapid aging in carbon membranes. Mechanistic investigations reveal that O<sub>2</sub> pyrolysis environment selectively removes relatively weakly-bound carbon species, altering pyrolysis intermediates, resulting in a nitrogen-rich framework with disordered nanodomains and heterogeneous ultramicroporosity. This work advances the material chemistry of ultrathin carbon membranes, attractive for ultrafast and high-precision molecular-sieving for molecular separation.</p>

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Oxygen-induced multimodal ultramicroporous structure in 10-nm-thick carbon membranes for enhanced hydrogen separation

  • 期刊论文

  • 出版模式：

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  • 发表日期：

    2026年5月22日

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  • Yueqing Shen,
  • Cédric Van Goethem,
  • Heng-Yu Chi,
  • Yinghui Li,
  • Linyi Li,
  • Nicole Barber,
  • Kuang-Jung Hsu,
  • Daniel Ortiz Trujillo,
  • Natalia Gasilova,
  • Adam Squires,
  • Shiqi Huang,
  • Kumar Varoon Agrawal

摘要

Carbon membranes yielding high selectivity as well as high permeance are attractive to advance the membrane-based gas separation. Herein, we report ultrathin carbon membranes (UCMs) which deliver enhanced gas separation performance through oxygen-modulated pyrolysis of poly(4-vinylpyridine) precursor. We show that O2 in pyrolysis environment, transforms the otherwise uniform carbon network featuring a ~ 3.9 Å characteristic interlayer spacing into disrupted UCMs (d-UCMs). These d-UCMs possess a multimodal ultramicroporous structure characterized by distinct d-spacings of ~3.4 Å, 3.9 Å, and 5.5 Å. This optimized distribution of free volume in a 10-nm-thick membrane enables a record combination of H2 permeance exceeding 10,000 gas permeation units (GPUs) and H2/N2 mixture selectivity surpassing 200. Meanwhile, d-UCM exhibits physical and thermal stability, showing no aging over 7 days of elevated temperature permeance testing, which overcomes the common issue of rapid aging in carbon membranes. Mechanistic investigations reveal that O2 pyrolysis environment selectively removes relatively weakly-bound carbon species, altering pyrolysis intermediates, resulting in a nitrogen-rich framework with disordered nanodomains and heterogeneous ultramicroporosity. This work advances the material chemistry of ultrathin carbon membranes, attractive for ultrafast and high-precision molecular-sieving for molecular separation.