Iyer Gaurav M, Ku Ching-En, Zhang Chen
Department of Chemical and Biomolecular Engineering, University of Maryland, College Park, MD, 20742, USA.
Sci Adv. 2025 Jun 6;11(23):eadt7512. doi: 10.1126/sciadv.adt7512. Epub 2025 Jun 4.
More than 90% of the world's hydrogen (H) is produced from fossil fuel sources, which requires energy-intensive separation and purification to produce high-purity H fuel and to capture the carbon dioxide (CO) by-product. While membranes can decarbonize H/CO separation, their moderate H/CO selectivity requires secondary H purification by pressure swing adsorption. Here, we report hyperselective carbon molecular sieve hollow fiber membranes showing H/CO selectivity 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 H/CO selectivity over 1400 under mixture permeation at 400°C. Pore structure characterization suggests that highly refined ultramicropores are responsible for effectively discriminating the closely sized H and CO molecules in the hyperselective carbon molecular sieve membrane. Modeling shows that the unprecedented H/CO selectivity will potentially allow one-step enrichment of fuel-grade H from shifted syngas for decarbonized H production.
全球90%以上的氢气（H）由化石燃料制取，这需要进行能源密集型的分离和提纯，以生产高纯度H燃料并捕获二氧化碳（CO）副产品。虽然膜可实现H/CO分离的脱碳，但它们适中的H/CO选择性需要通过变压吸附进行二次H提纯。在此，我们报道了一种超选择性碳分子筛中空纤维膜，在150°C的混合气体渗透条件下，其H/CO选择性超过7000，这比文献报道的最具选择性的非金属膜高出近30倍。该膜在400°C的混合气体渗透条件下，能够在1400以上保持超高的H/CO选择性。孔隙结构表征表明，高度精细的超微孔是超选择性碳分子筛膜中有效区分尺寸相近的H和CO分子的原因。模型显示，前所未有的H/CO选择性可能使一步法从变换合成气中富集燃料级H以生产脱碳H成为可能。
