Facile synthesis of a continuous thin Cu(bipy)2(SiF6) membrane with selectivity towards hydrogen

Abstract

Cu(bipy)2(SiF6) is a highly porous metal-organic framework (MOF) and represents a prototypal "pillared sheet" platform o?ering opportunities to control the pore sizes. Its structural features, low cost and facile synthesis make it a great candidate to fabricate membranes for gas separation. The key to obtaining thin, continuous Cu(bipy)2(SiF6) membranes is to control the Cu(bipy)2(SiF6) crystal growth and enhance the binding between membrane and substrate. Here we explored a new route by direct synthesis and successfully obtained a continuous thin Cu(bipy)2(SiF6) membrane on a macroporous glass-frit disk with high robustness. It is speculated that the SiF6 2- used to construct the Cu(bipy)2(SiF6) membrane came from the ?uorinated substrate. The Cu(bipy)2(SiF6) membrane shows the separation factors of H2-CO2, H2-CH4 and H2-N2 are 8.0, 7.5, and 6.8 respectively at 293 K and 1 bar with H2 permeance of 2.7* 10- 7 mol m-2 s -1 Pa-1 as well as high thermal stability. We expect to explore more membranes of Cu(bipy)2(SiF6) analogues with tuneable pore sizes using this route and to obtain membranes with higher gas separation performance.