Metal–organic framework channelled graphene composite membranes for H2/CO2 separation
Graphene-based materials offer great potential in gas separation. However, it remains a challenge to control the interlayer structure to obtain membranes with high permeability. We describe a route for the fabrication of metal–organic framework (MOF) channelled graphene composite membranes with molecular sieving properties by in situ crystallization. Based on polar oxygen groups, extended interlayer spacing and electronegativity, MOF nanosheets can easily be impregnated into interlayers of reduced graphene oxide (rGO), which strongly anchor and bolster up rGO by coordination bonds to form a porous architecture with uniform nanochannels. The H2/CO2 selectivity of ZIF-8/rGO membranes reached about 26.4. Moreover, many other MOF materials were also inserted between rGO sheets to obtain membranes with both high selectivity (larger than 10.3) and superior permeability (in the range of 73–21 112 barrer).