Atomically Fine-Tuning Organic-Inorganic Carbon Molecular Sieve Membranes for Hydrogen Production.
basic_science · Level V
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- Record sourced from PubMed, PMID 39831883.
- Also identified by DOI 10.1021/acsnano.4c15126.
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Abstract
Polymeric membranes with great processability are attractive for the H<sub>2</sub>/CO<sub>2</sub> separation required for hydrogen production from renewable biomass with carbon capture for utilization and sequestration. However, it remains elusive to engineer polymer architectures to obtain desired sub-3.3 Å ultramicropores to efficiently sieve H<sub>2</sub> from CO<sub>2</sub>. Herein, we demonstrate a scalable way of carbonizing polybenzimidazole (PBI) at low temperatures, followed by vapor phase infiltration (VPI) to atomically narrow ultramicropores throughout the films, forming hybrid organic-inorganic carbon molecular sieves (CMSs). One VPI cycle (100 s) for the PBI carbonized at 500 °C remarkably increases H<sub>2</sub>/CO<sub>2</sub> selectivity from 9.6 to 83 at 100 °C, surpassing Robeson's upper bound. The CMS demonstrates a stable H<sub>2</sub>/CO<sub>2</sub> separation performance when challenged with simulated syngas streams and can be fabricated into thin-film composite membranes, outperforming state-of-the-art membranes. The scalable approach can be ubiquitous to molecularly fine-tune ultramicropores of leading polymeric membranes to further improve their size-sieving ability and thus separation efficiency.