open access

https://hdl.handle.net/2115/87812

Free-Standing Nanometer-Thick Covalent Organic Framework Films for Separating CO2 and N-2

英語

CO2 separation membrane

2022-02-01

American Chemical Society

ACS Applied Nano Materials

5(2)

2367-2374

Covalent organic frameworks (COF) have been gathering much attention because the shapes, sizes, and chemical functions of their nanostructured pores can be arbitrarily controlled by designing the organic precursors. We fabricated cm-sized free-standing COF films with the thickness of 50-100 nm by an alternating vacuum deposition polymerization method. Precise adjustment of the stoichiometry by digitally controlled deposition was essential for producing the robust free-standing COF films. High-resolution electron microscopy revealed 3 nm pore structures, which correspond to the atomic structure of the COF. Small angle X-ray diffraction shows the existence of a similar periodicity. The CO2/N-2 gas phase separation properties were evaluated from 10(3)-10(5) Pa, and the parameters for each molecular permeation were determined. Based on the detailed analysis, it was found that the selectivity comes from the greater sorption affinity of CO2 to the COF compared to N-2, which is consistent with the quantum chemical calculation. Since the vapor phase method can be used to coat various shaped templates, our method provides a new option for fabrication of neat COF membranes with various structures and their applications for the separation membrane.

学術雑誌論文

Accepted Manuscript

This document is the Accepted Manuscript version of a Published Work that appeared in final form in ACS Applied Nano Materials, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see ACS Applied Nano Materials.

2574-0970