Tellurium–Oxygen Molecules Bridging MFI Zeolite Nanoplates into a b -Oriented Membrane for CO2 Separation

The orientation of zeolite pores parallel to gas transport can facilitate rapid selective gas separation; however, the fabrication of oriented zeolite membranes remains a grand challenge. This study reports a unique strategy of molecularly bridging zeolite nanoplates to fabricate a b-oriented MFI membrane for CO2 gas separation. Tellurium alkoxide of Te(C3H6O2)2 is designed as the bridging agent, and the MFI zeolite nanoplate is synthesized in the aspect ratio of ∼14 as the building block. The bridging of MFI nanoplates occurs via the condensation reaction with tellurium alkoxide, and the resultant membrane exhibits b-orientation with straight pores of ∼ 5 Å running perpendicular to the membrane surface. The molecular bridging enables high membrane continuity for CO2 separation with exceptional separation factors of 33.0 and 36.8 for CO2/N2 and CO2/CH4, respectively. The straight pores bestow high CO2 permeance up to 20 × 10–7 mol m–2 s–1 Pa–1. This strategy is advantageous over conventional approaches by virtue of better control on membrane orientation and less dependence on support. The superior performance compared to those of the state-of-the-art zeolite membranes promises such b-oriented MFI membranes great potential in industrial CO2 separation.