An innovative strategy is proposed to synthesize single-crystal nanowires (NWs) of the Al3+ dicarboxylate MIL-69(Al) MOF by using graphene oxide nanoscrolls as structure-directing agents. MIL-69(Al) NWs with an average diameter of 70±20 nm and lengths up to 2 μm were found to preferentially grow along the [001] crystallographic direction. Advanced characterization methods (electron diffraction, TEM, STEM-HAADF, SEM, XPS) and molecular modeling revealed the mechanism of formation of MIL-69(Al) NWs involving size-confinement and templating effects. The formation of MIL-69(Al) seeds and the self-scroll of GO sheets followed by the anisotropic growth of MIL-69(Al) crystals are mediated by specific GO sheets/MOF interactions. This study delivers an unprecedented approach to control the design of 1D MOF nanostructures and superstructures.
Keywords: graphene oxide; metal-organic frameworks; nanowires; self-assembly; templates.
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