Remarkable Enhancement of Proton Conductivity by Introducing Imidazole into MOFs and Forming Composite Membranes

Abstract

A novel metal-organic framework, [Zn 2 (HCOO)(trz) 3 ] n (1), has been successfully synthesized under solvothermal conditions. The central Zn II ions exhibit two different coordination environments: [ZnN 3 O] and [ZnN 6 ], in which the coordination N and O atoms are from Htrz and formic acid molecules. To effectively improve the proton conductivity of 1, imidazole molecules are introduced into 1 to obtain 2HIm@1 (named as 2). Moreover, composite membranes of 2-PVA-X (X = 5, 10, 15, 20wt.-%) are prepared. Alternating current (AC) impedance measurements reveal that 1 displays proton conductivity Eur. 795The proton conductivity of the composite membranes were tested in the humidity of 65 %, 75 %, 86 %, 93 % and 98 % RH

Bifunctional Metal–Organic Framework Functionalized by Dimethylamine Cations: Proton Conduction and Iodine Vapor Adsorption

“…Compared with these materials, MOFs are easier to design and control their internal structure. Methods such as doping guest molecules in the pores of MOFs and modifying ligands are all used to improve conductivity. − …”

Designable Guest‐Molecule Encapsulation in Metal–Organic Frameworks for Proton Conductivity

“…Then they encap- sulated imidazole into this Zn II MOF. [28] The obtained composite material shows high proton conductivity of 1.51 × 10 À 4 S cm À 1 at 98 % RH and 318 K while the value of original MOF is only 7.95 × 10 À 7 S cm À 1 . It is worth noting that the highest proton conductivity of the prepared composite material is three orders of magnitude higher than that of the initial MOF.…”

“…In 2018, the Zhang and Wang group synthesized a novel MOF, [Zn 2 (HCOO)(trz) 3 ] n (Htrz=1,2,4‐triazole). Then they encapsulated imidazole into this Zn II MOF [28] . The obtained composite material shows high proton conductivity of 1.51×10 −4 S cm −1 at 98 % RH and 318 K while the value of original MOF is only 7.95×10 −7 S cm −1 .…”

Selective Unidirectional Transport of Protons in Sub-Nanoporous Membranes Inspired by the Influenza A M2 Channel for Nanofluidic Ionic Diodes

“…To date, ordered two-dimensional and three-dimensional (2D and 3D) porous structural materials were used to construct proton transport materials, such as silica, − porous coordination polymers, − and covalent organic frameworks. − The ordered pore material realizes the proton Grotthuss transfer in the pore channel since the modified hydrophilic group in the pore channel increases the relative humidity, ensures the entry of water molecules, and provides a water-mediated hydrogen bond network for protons . Although these materials were capable of proton transport, most of these materials either can only achieve proton selectivity while cannot achieve unidirectionality due to isotropy or unidirectionality can be achieved while proton selectivity cannot be achieved due to the inability to precisely control the pore size.…”