6533b834fe1ef96bd129e1c1

RESEARCH PRODUCT

Determination of Geometry Arrangement of Copper Ions in HKUST-1 by XAFS During a Prolonged Exposure to Air

Franco Mario GelardiMichela TodaroMichela TodaroGianpiero BuscarinoLuisa Sciortino

subject

Extended X-ray absorption fine structureElectronic Optical and Magnetic MaterialAnalytical chemistrychemistry.chemical_element02 engineering and technology010402 general chemistry021001 nanoscience & nanotechnology01 natural sciencesCopperXANES0104 chemical sciencesSurfaces Coatings and FilmsElectronic Optical and Magnetic MaterialsX-ray absorption fine structureIonEnergy (all)General EnergyAdsorptionchemistryMoleculePhysical and Theoretical ChemistryAbsorption (chemistry)0210 nano-technology

description

We present an experimental investigation focused on the local structural changes taking place around Cu2+ions in metal− organic framework (MOF) HKUST-1 for different times of exposure to air by XAFS (X-ray absorption fine structure). The analysis involves both XANES (X-ray absorption near edge structure) and EXAFS (extended X-ray absorption fine structure) regions around the Cu K-edge. Starting from the paddle-wheel structures proposed in literature, a more detailed description of the geometrical environment of Cu2+ions has been found. In particular, the paddle-wheel structure of a fresh sample, which means a pristine HKUST-1 material with a single water molecule weakly adsorbed on each Cu2+ion, has been disclosed for the first time. Furthermore, after 20 days of exposure to air, relevant structural changes with respect to the pristine sample have been evidenced. An activation process has demonstrated that these local changes are totally reversible, in agreement with a recent model of the decomposition process of HKUST-1 proposed in literature.

yearjournalcountryeditionlanguage
2017-10-26The Journal of Physical Chemistry C
https://doi.org/10.1021/acs.jpcc.7b07792