A Triazole-Containing Metal–Organic Framework as a Highly Effective and Substrate Size-Dependent Catalyst for CO2 Conversion
2016
Li, Pei-Zhou | Wang, Xiao-Jun | Liu, Jia | Lim, Jie Sheng | Zou, Ruqiang | Zhao, Yanli
A highly porous metal–organic framework (MOF) incorporating both exposed metal sites and nitrogen-rich triazole groups was successfully constructed via solvothermal assembly of a clicked octcarboxylate ligand and Cu(II) ions, which presents a high affinity toward CO₂ molecules clearly verified by gas adsorption and Raman spectral detection. The constructed MOF featuring CO₂-adsorbing property and exposed Lewis-acid metal sites could serve as an excellent catalyst for CO₂-based chemical fixation. Catalytic activity of the MOF was confirmed by remarkably high efficiency on CO₂ cycloaddition with small epoxides. When extending the substrates to larger ones, its activity showed a sharp decrease. These observations reveal that MOF-catalyzed CO₂ cycloaddition of small substrates was carried out within the framework, while large ones cannot easily enter into the porous framework for catalytic reactions. Thus, the synthesized MOF exhibits high catalytic selectivity to different substrates on account of the confinement of the pore diameter. The high efficiency and size-dependent selectivity toward small epoxides on catalytic CO₂ cycloaddition make this MOF a promising heterogeneous catalyst for carbon fixation.
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