Membrane built to trap CO2 delivers unprecedented 1,800× hydrogen separation

Researchers at the University at Buffalo and collaborators have developed a novel membrane made of crosslinked polyamines that was originally designed to attract carbon dioxide (CO2). Contrary to expectations, the membrane binds CO2 so strongly that it effectively blocks its passage rather than increasing permeability. This unexpected behavior led scientists to explore the membrane’s ability to separate hydrogen from CO2 in mixed gas streams, resulting in a record-breaking selectivity of 1,800—meaning hydrogen passes through the membrane 1,800 times more easily than CO2. This performance far surpasses previous benchmarks, which were around a selectivity of 100. The breakthrough has significant implications for industrial hydrogen purification, a critical process for fuel-cell technologies and the transition to low-carbon energy systems. The polymer-based membrane can be manufactured as an industrial thin-film composite and demonstrates durability under extreme conditions, including self-healing capabilities. This energy-efficient technology addresses the substantial global energy consumption associated with conventional chemical separations, which account for up to 15%