To enhance the carbon dioxide (CO2) uptake of metal-organic frameworks (MOFs), amine functionalization of their pore surfaces has been studied extensively. In general, amine-functionalized MOFs have been synthesized via post-synthetic modifications. Herein, we introduce a one-step construction of a MOF ([(NiLethylamine)(BPDC)]=MOFNH2; [NiLethylamine]2+=[Ni(C12H32N8)]2+; BPDC2-=4,4′-biphenyldicarboxylate) possessing covalently tethered alkylamine groups without post-synthetic modification. Two-amine groups per metal centre were introduced by this method. MOFNH2 showed enhanced CO2 uptake at elevated temperatures, attributed to active chemical interactions between the amine groups and the CO2 molecules. Due to the narrow channels of MOFNH2, the accessibility to the channel of CO2 is the limiting factor in its sorption behaviour. In this context, only crystal size reduction of MOFNH2 led to much faster and greater CO2 uptake at low pressures.
Bibliographical noteFunding Information:
We acknowledge financial support from the Korea CCS R&D Centre (KCRC) grant funded by the Korea government (Ministry of Science, ICT & Future Planning) (NRF-2014M1A8A1049255) and Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (NRF-2013R1A1A3010846).
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