TY - Journal Article AU - Cacho-Bailo, Fernando AU - Matito-Martos, Ismael AU - Perez-Carbajo, Julio AU - Etxeberría-Benavides, Miren AU - Karvan, Oğuz AU - Sebastián, Víctor AU - Calero, Sofía AU - Téllez, Carlos AU - Coronas, Joaquín TI - On the molecular mechanisms for the H2/CO2 separation performance of zeolite imidazolate framework two-layered membranes PY - 2017 PB - ROYAL SOC CHEMISTRY, THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND AB - Double-layered zeolitic imidazolate framework (ZIF) membranes were fabricated inside polyimide P84 hollow fibers by a step-synthesis conducted by microfluidic technology and applied to pre-combustion gas separation. Our hypothesis, based on the information provided by a combination of molecular simulation and experiments, is that a CO2 adsorption reduction on the surface of the ZIF-9 would enhance the molecular sieving effect of this ZIF-9 layer and therefore the selectivity in the H-2/CO2 mixture separation of the entire membrane. This reduction would be achieved by means of a less-CO2-adsorptive methylimidazolate-based ZIF-67 or ZIF-8 layer coating the ZIF-9. ZIF-8/ZIF-9 and ZIF-67/ZIF-9 double-layered membranes were prepared and characterized by XRD, FTIR, SEM, FIB, TEM and EDS. This unprecedented strategy led to a H-2/CO2 separation selectivity of 9.6 together with a 250 GPU H-2 permeance at 150 degrees C, showing a significant improvement with respect to the pure ZIF-9 membrane. Double-layered membranes also showed higher apparent CO2 activation energies than single-layered membranes, attributable to a diminished adsorption. SN - 2041-6520 UR - http://hdl.handle.net/11556/378 DX - 10.1039/c6sc02411d ER -