Enhanced proton conductivity in a flexible metal-organic framework promoted by single-crystal-to-single-crystal transformation.

Xi Chen,George Whitehead,Chiu C Tang,Xue Han,Inigo J Vitorica-Yrezabal,Zhongyue Zhang,Sihai Yang,Sergei Sapchenko,Ivan Da-Silva,Jin Chen,Kunio Awaga,Martin Schröder,Ming Li

doi:10.1039/d0cc05270a

Abstract

MFM-722(Pb)-DMA undergoes a single-crystal-to-single-crystal (SCSC) transformation to give MFM-722(Pb)-H2O via ligand substitution upon exposure to water vapour. In situ single crystal impedance spectroscopy reveals an increase in proton conductivity due to this structural transition, with MFM-722(Pb)-H2O showing a proton conductivity of 6.61 × 10-4 S cm-1 at 50 °C and 98% RH. The low activation energy (Ea = 0.21 eV) indicates that the proton conduction follows a Grotthuss mechanism.

Highlights

Xi Chen,a Zhongyue Zhang,*b Jin Chen,a Sergei Sapchenko,a Xue Han,a Ivan da-Silva, c Ming Li, d Inigo J
We report the SCSC transformation via ligand substitution in a nonporous Pb(II)-based Metal–organic framework (MOF), MFM-722(Pb)-DMA, and the enhancement of proton conductivity in the resultant MFM-722(Pb)-H2O
Single crystal impedance spectroscopy can reduce the impact of grain boundaries that are inherent in bulk-pellet measurements,[24] and has been employed here to evaluate the change of proton conductivity of MFM-722(Pb)-DMA during the SCSC transformation on exposure to water vapour

Summary

Introduction

Xi Chen,a Zhongyue Zhang,*b Jin Chen,a Sergei Sapchenko,a Xue Han,a Ivan da-Silva, c Ming Li, d Inigo J. In situ single crystal impedance spectroscopy reveals an increase in proton conductivity due to this structural transition, with MFM-722(Pb)-H2O showing a proton conductivity of 6.61 Â 10À4 S cmÀ1 at 50 8C and 98% RH.

Results

Conclusion