posted on 2020-04-01, 19:13authored byHongwei Fan, Manhua Peng, Ina Strauss, Alexander Mundstock, Hong Meng, Jürgen Caro
In
this study, we propose a new concept of vertically aligned 2D
covalent organic framework (COF) layers forming a membrane for efficient
gas separation on the basis of precise size exclusion. Gas transport
takes place through the COF interlayer space (typically 0.3–0.4
nm) rather than through the nanometer-sized pore apertures. Construction
of such a unique membrane architecture was implemented via in situ oriented growth of 2D COFs inside a skeleton of
vertically aligned CoAl-layered double hydroxide (LDH) nanosheets.
The resultant vertical COF-LZU1 membrane exhibits a high H2 permeance of ∼3600 GPU together with a desirable separation
selectivity for gas mixtures such as H2/CO2 (31.6)
and H2/CH4 (29.5), thus surpassing the 2008
Robeson upper bounds. The universality of this approach was demonstrated
by successfully producing two types of high-quality vertical COF membranes
with superior performance as well as outstanding running stability.