Selective dinitrogen binding to transition metal ions mainly covers two strategic domains: biological nitrogen fixation catalysed by metalloenzyme nitrogenases, and adsorptive purification of natural gas and air. Many transition metal-dinitrogen complexes have been envisaged for biomimetic nitrogen fixation to produce ammonia. Inspired by this concept, here we report mesoporous metal-organic framework materials containing accessible Cr(III) sites, able to thermodynamically capture N2 over CH4 and O2. This fundamental study integrating advanced experimental and computational tools confirmed that the separation mechanism for both N2/CH4 and N2/O2 gas mixtures is driven by the presence of these unsaturated Cr(III) sites that allows a much stronger binding of N2 over the two other gases. Besides the potential breakthrough in adsorption-based technologies, this proof of concept could open new horizons to address several challenges in chemistry, including the design of heterogeneous biomimetic catalysts through nitrogen fixation.
Bibliographical noteFunding Information:
We would like to acknowledge the financial support from the R&D Convergence Program (CRC-14-1-KRICT) of MSIP (Ministry of Science, ICT and Future Planning) and NST (National Research Council of Science & Technology) of Republic of Korea. KRICT authors thank the Global Frontier Center for Hybrid Interface Materials (GFHIM) for its financial support (Grant No. NRF-2013M3A6B1078879). M.D., G.M. and C.S. thank CNRS (Centre National de la Recherche Scientifique) for its financial support. RGN members acknowledge the financial support through the DRC Program (SKM-1503) funded by NST (National Research Council of Science & Technology) of Korea. G.M. thanks Institut Universitaire de France for its support. Y.J. acknowledges the support from the National Research Foundation of Korea funded by the Korean Government (NRF-2016M3D1A1021147). We thank CCME members for their contributions to the synthesis and characterization of MIL-100(M) samples. J.-S.C. also thanks Y.-U. Kwon (SKKU) for his comment on artificial N2 fixation.
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All Science Journal Classification (ASJC) codes
- Materials Science(all)
- Condensed Matter Physics
- Mechanics of Materials
- Mechanical Engineering