With the continuously increasing global energy demand, selective capture of anthropogenic CO2 from fossil fuel-fired power plants is needed to mitigate the negative effects of CO2 on the environment. This triggers the use of metal-organic frameworks (MOF) as CO2 adsorbents due to their tunable structure through the variation of MOF components (i.e., metal center source and organic linker source) prior to MOF synthesis. This can lead to the introduction of functionalities beneficial to CO2 capture into MOF structure that can also provide polarity, acidity/basicity, and flexibility. In this study, Zn-based MOFs (ZnMOFs) have been synthesized using pyridine-based organic linkers to provide free pyridine functionalities with Lewis basicity. Surprisingly, instead of incorporating free pyridine functionalities, these ZnMOFs were demonstrated to have unique pore geometries with the presence of Lewis acidic open Zn2+ sites. These sites were shown to be accessible to CO2, as evidenced by in-situ DRIFT studies using acetic acid as a probe molecule.1 Structural investigation of ZnMOFs also suggests their use as templates/precursors for the formation of hierarchical nanoporous carbons (NC) with N dopants via carbonization. The use of ZnMOFs as templates was shown to direct macroscopic morphology and porosity of the resulting NC materials.2,3 In addition, the properties of the NC materials can be tuned via the alteration of organic linker (MOF precursor) prior to ZnMOF synthesis. Using the ZnMOFs described here, the surface area and final amount of N species in the NC materials were controlled through the variation of molar ratios of Zn/C and N/C inherent to the parent ZnMOF. The presence of N dopants in the NC materials led to their use as CO2 adsorbents. Furthermore, these NC materials exhibited high recyclability during thirty CO2 adsorption/desorption cycles. References (1) Kim, J.; Oliver, A. G.; Neumann, G. T.; Hicks, J. C. Dalton Trans. 2014, submitted. (2) Jiang, H. L.; Liu, B.; Lan, Y. Q.; Kuratani, K.; Akita, T.; Shioyama, H.; Zong, F.; Xu, Q. J. Am. Chem. Soc. 2011, 133, 11854. (3) Aijaz, A.; Fujiwara, N.; Xu, Q. J. Am. Chem. Soc. 2014, 136, 6790.

Zn-MOFs with pyridine-based organic linkers and their carburized, N-doped carbons analogues as CO2 capture adsorbents

249th National Meeting (2015)

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