Facile fabrication of MIL-103(Eu) porous coordination polymer nanostructures and their sorption and sensing properties

Abstract

Nano/microscale lanthanide porous coordination polymer MIL-103(Eu) [Eu(BTB)] (H₃BTB = 4,4′,4′′-benzene-1,3,5-triyl-tribenzoic acid) crystals have been fabricated at room temperature by a facile, convenient and environmentally friendly method. The structures of the products were confirmed by powder X-ray diffraction, and the crystal morphologies, including microrods, nanorods and nanospheres, were characterized by scanning electron microscopy. It is found that the addition of sodium acetate and the concentration of the reactants have an important impact on the morphology and size of the MIL-103(Eu) crystals. Gas adsorption measurements reveal that the products show high specific surface areas among the rare earth based coordination polymers and the MIL-103(Eu) nanorods can selectively adsorb CO₂ over N₂ under ambient conditions. Furthermore, all the products exhibit red emission corresponding to the ⁵D₀ → ⁷F₂ transition of the Eu(III) ion, and MIL-103(Eu) nanorods display sensitive and selective sensing for Cu(II) ions and acetone molecules in solution.