title: pH-dependent proton conducting behavior in a metal-organic framework material.
abstract: A porous metal-organic framework (MOF), [Ni2(dobdc)(H2O)2]⋅6 H2O (Ni2(dobdc) or Ni-MOF-74; dobdc(4-)=2,5-dioxido-1,4-benzenedicarboxylate) with hexagonal channels was synthesized using a microwave-assisted solvothermal reaction. Soaking Ni2(dobdc) in sulfuric acid solutions at different pH values afforded new proton-conducting frameworks, H(+)@Ni2(dobdc). At pH 1.8, the acidified MOF shows proton conductivity of 2.2×10(-2) S cm(-1) at 80 °C and 95% relative humidity (RH), approaching the highest values reported for MOFs. Proton conduction occurs via the Grotthuss mechanism with a significantly low activation energy as compared to other proton-conducting MOFs. Protonated water clusters within the pores of H(+)@Ni2(dobdc) play an important role in the conduction process.
authors.affiliation: Department of Chemistry, Korea University, Seoul 136-713 (Korea).
authors.forename: Won Ju
authors.initials: WJ
authors.lastname: Phang
authors.forename: Woo Ram
authors.initials: WR
authors.lastname: Lee
authors.forename: Kicheon
authors.initials: K
authors.lastname: Yoo
authors.forename: Dae Won
authors.initials: DW
authors.lastname: Ryu
authors.forename: BongSoo
authors.initials: B
authors.lastname: Kim
authors.forename: Chang Seop
authors.initials: CS
authors.lastname: Hong
keywords: metal-organic frameworks; proton conducting materials; protonated water clusters