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Indexed by:Journal Papers

Date of Publication:2016-01-01

Journal:RSC ADVANCES

Included Journals:SCIE、EI

Volume:6

Issue:45

Page Number:38774-38781

ISSN No.:2046-2069

Abstract:A series of tailored covalent organic frameworks (COFs), i.e. [N=N](X%)-TAPH-COFs and [C=C](X%)-TAPH-COFs, were synthesized by post-fabrication of [HO](X%)-TAPH-COFs with 4-phenylazobenzoyl chloride (PhAzo) and 4-stilbenecarbonyl chloride (PhSti), respectively. Powder X-ray diffraction (PXRD), FT-IR, and solution-state H-1 NMR of the digested COFs were applied to clarify the functional groups integrated in the pore channels. Gas sorption isotherms confirmed that the [N=N](X%)-TAPH-COFs and [C=C](X%)-TAPH-COFs had moderate surface areas, narrow pore sizes, and good physicochemical stability. Compared with [C=C](X%)-TAPH-COFs, the [N=N](X%)-TAPH-COFs exhibited higher CO2 uptake capacities of up to 207 mg g(-1) (273 K and 1 bar), isosteric heats of adsorption for CO2 (30.7-43.4 kJ mol(-1)), and CO2/N-2 selectivities of up to 78 (273 K) because of the dipole interactions between the azo group and CO2 as well as the N-2-phobic behavior of the azo group. Furthermore, although the decreased pore size was advantageous for increasing CO2 adsorption, the decreased surface area of the COFs would undoubtedly decrease CO2 adsorption if too many functional groups were introduced.