Heat-driven molecule gatekeepers in MOF membrane for record-high H2 selectivity | Science Advances
Abstract
Hydrogen/carbon dioxide (H
2
/CO
2
) separation for sustainable energy is in desperate need of reliable membranes at high temperatures. Molecular sieve membranes take their nanopores to differentiate sizes between H
2
and CO
2
but have compromised at a marked loss of selectivity at high temperatures owing to diffusion activation of CO
2
. We used molecule gatekeepers that were locked in the cavities of the metal-organic framework membrane to meet this challenge. Ab initio calculations and in situ characterizations demonstrate that the molecule gatekeepers make a notable move at high temperatures to dynamically reshape the sieving apertures as being extremely tight for CO
2
and restitute with cool conditions. The H
2
/CO
2
selectivity was improved by an order of magnitude at 513 kelvin (K) relative to that at the ambient temperature.