Oxygenic iron clusters in ZSM-5 zeolite promote quantum sieving of gaseous hydrogen isotopes
摘要
Isotopic separation is of paramount importance for producing high-purity heavy hydrogen, yet the process remains hugely challenging. Here, we report on an Fe/ZSM-5 zeolite that was able to efficiently separate deuterium from protium via chemical quantum sieving. Structural data showed that four types of Fe species were present in Fe/ZSM-5 and oligomeric Fe–O clusters in the zeolite pores were correlated directly with gas selectivity. Gas adsorption revealed that Fe–O species served as the main adsorption sites and interacted with D2 more strongly than with H2. D2/H2 separation was exemplified using thermal desorption spectroscopy. D2/H2 selectivity increased with Fe loading in Fe/ZSM-5 and a selectivity of 32.1 was obtained with an optimal loading of 7 wt%. The shift of desorption temperature supports the chemical affinity-based quantum sieving of D2 over H2. This study demonstrates an effective strategy for enhancing D2/H2 separation and the high selectivity means that Fe/ZSM-5 has strong potential in hydrogen isotope separation.