Metal–Organic Frameworks Containing Missing‐Linker Defects Leading to High Hydroxide‐Ion Conductivity |
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| Authors: | Dr. Carmen Montoro Prof. Dr. Pilar Ocón Dr. Félix Zamora Prof. Dr. Jorge A. R. Navarro |
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| Affiliation: | 1. Departamento de Química Inorgánica, Universidad de Granada, 18071, Granada, Spain), Fax: (+34) 958 248526;2. Departamento de Química Física Aplicada, Universidad Autónoma de Madrid, Madrid, Spain;3. Departamento de Química Inorgánica, Universidad Autónoma de Madrid, Madrid, Spain |
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| Abstract: | The ionic conductivity properties of the face‐centered cubic [Ni8(OH)4(H2O)2(BDP_X)6] (H2BDP_X=1,4‐bis(pyrazol‐4‐yl)benzene‐4‐X with X=H ( 1 ), OH ( 2 ), NH2 ( 3 )) metal–organic framework (MOF) systems as well as their post‐synthetically modified materials K[Ni8(OH)5(EtO)(BDP_X)5.5] ( 1@KOH , 3@KOH ) and K3[Ni8(OH)3(EtO)(BDP_O)5] ( 2@KOH ), which contain missing‐linker defects, have been studied by variable temperature AC impedance spectroscopy. It should be noted that these modified materials exhibit up to four orders of magnitude increase in conductivity ‐values in comparison to pristine 1 – 3 systems. As an example, the conductivity value of 5.86×10?9 S cm?1 (activation energy Ea of 0.60 eV) for 2 at 313 K and 22 % relative humidity (RH) increases up to 2.75×10?5 S cm?1 (Ea of 0.40 eV) for 2@KOH . Moreover, a further increase of conductivity values up to 1.16×10?2 S cm?1 and diminution of Ea down to 0.20 eV is achieved at 100 % RH for 2@KOH . The increased porosity, basicity and hydrophilicity of the 1@KOH – 3@KOH materials compared to the pristine 1 – 3 systems should explain the better performance of the KOH‐modified materials. |
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| Keywords: | defects impedance spectroscopy ion conductivity metal– organic frameworks nickel |
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