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Abstract Over the last two decades, polymers with superior H2/CO2separation properties at 100–300 °C have gathered significant interest for H2purification and CO2capture. This timely review presents various strategies adopted to molecularly engineer polymers for this application. We first elucidate the Robeson's upper bound at elevated temperatures for H2/CO2separation and the advantages of high‐temperature operation (such as improved solubility selectivity and absence of CO2plasticization), compared with conventional membrane gas separations at ~35 °C. Second, we describe commercially relevant membranes for the separation and highlight materials with free volumes tuned to discriminate H2and CO2, including functional polymers (such as polybenzimidazole) and engineered polymers by cross‐linking, blending, thermal treatment, thermal rearrangement, and carbonization. Third, we succinctly discuss mixed matrix materials containing size‐sieving or H2‐sorptive nanofillers with attractive H2/CO2separation properties.
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This content will become publicly available on June 4, 2026
Hyperselective carbon membranes for precise high-temperature H2 and CO2 separation
More than 90% of the world’s hydrogen (H2) is produced from fossil fuel sources, which requires energy-intensive separation and purification to produce high-purity H2fuel and to capture the carbon dioxide (CO2) by-product. While membranes can decarbonize H2/CO2separation, their moderate H2/CO2selectivity requires secondary H2purification by pressure swing adsorption. Here, we report hyperselective carbon molecular sieve hollow fiber membranes showing H2/CO2selectivity exceeding 7000 under mixture permeation at 150°C, which is almost 30 times higher than the most selective nonmetallic membrane reported in the literature. The membrane is able to maintain an ultrahigh H2/CO2selectivity over 1400 under mixture permeation at 400°C. Pore structure characterization suggests that highly refined ultramicropores are responsible for effectively discriminating the closely sized H2and CO2molecules in the hyperselective carbon molecular sieve membrane. Modeling shows that the unprecedented H2/CO2selectivity will potentially allow one-step enrichment of fuel-grade H2from shifted syngas for decarbonized H2production.
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- Award ID(s):
- 2044794
- PAR ID:
- 10600100
- Publisher / Repository:
- American Association for the Advancement of Science
- Date Published:
- Journal Name:
- Science Advances
- Volume:
- 11
- Issue:
- 23
- ISSN:
- 2375-2548
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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