The proton conduction mechanism in a material consisting of packed acids

Ogawa, Takahira; Aonuma, Takamasa; Tamaki, Takanori; Ohashi, Hidenori; Ushiyama, Hiroshi; Yamashita, Koichi; Yamaguchi, Takeo

doi:10.1039/c4sc00952e

Cited by 77 publications

(93 citation statements)

References 46 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The latter value is comparable to the best proton-conducting MOFs whose proton conduction is solely mediated by water molecules, either lattice or coordinated (a detailed comparison is given in Table T1 in the ESI). [51][52][53] To study the role of lattice water molecules on the proton conductivity and also confirm the structural flexibility of the framework, we ran impedance analyses using the pristine NdMo−MOF activated at 130 °C and 150 °C, respectively (data shown in the ESI, Figure S4). These results also show that the coordinated water is a poor proton conductor.…”

Section: -33mentioning

confidence: 99%

High proton conductivity in cyanide-bridged metal–organic frameworks: understanding the role of water

et al. 2015

View full text Add to dashboard Cite

Supplementary Information (ESI) available: IR, PXRD, TGA and proton conductivity analysis for the as-synthesized NdMo−MOF and its activated forms at 80 °C, 130 °C and 150 °C, respectively. SeeWe investigate and discuss the proton conductivity properties of the cyanide-bridged metal-organic framework (MOF) [Nd(mpca)2Nd(H2O)6Mo(CN)8]·nH2O (where mpca is 5−methyl−2−pyrazinecarboxylate). This MOF is one of an exciting class of cyanide-bridged materials that can combine porosity with magnetism, luminescene, and proton conductivity. Specifically, we show that this material features highly hydrophilic open channels filled with water molecules. They enable a high proton conductivity, as much as 10 -3 S cm -1 . A rich hydrogen-bonding network, formed by the ligands' carboxylate groups with both coordinated and lattice water molecules, facilitates this high proton conductivity. Combined thermogravimetric studies, FTIR spectroscopy and PXRD analysis show that upon heating at 80 °C, the lattice water molecules are removed without any change in the framework. Further heating at 130 °C results in a partial removal of the coordinated water molecules, while still retaining the original framework. These activated MOFs shows an increasing conductivity from ~10 -9 S cm -1 to ~10 -3 S cm -1 when the relative humidity increases from 0% to 98%. Our studies show that the increase in proton conductivity is correlated with the re-hydration of the framework with lattice water molecules. The Arrhenius activation energy for the proton conductivity process is low (Ea = 37 kJ·mol -1 ), indicating that the protons "hop" through the channels following the Grotthuss mechanism. The fact that this MOF is remarkably stable both under high humidity conditions and at relatively high temperatures (up to 130 °C) makes it a good candidate for real-life applications.

show abstract

Section: -33mentioning

confidence: 99%

High proton conductivity in cyanide-bridged metal–organic frameworks: understanding the role of water

et al. 2015

View full text Add to dashboard Cite

show abstract

“…Apparently, the proton conductivities of the PVA‐AA/CA biocomposite membranes are higher compared to that of PVA blend membrane. AA promotes the proton conduction both through hopping and vehicular mechanisms and dipolar zwitterions rapidly transmit the protons . AA constitutes an array of acid–base pairs that acts simultaneously as a proton donor and proton acceptor leads to fast proton transfer through hopping mechanism.…”

Section: Resultsmentioning

confidence: 99%

Biocomposite proton‐exchange membrane electrolytes for direct methanol fuel cells

Suganthi

Mohanapriya

Raj

2016

J of Applied Polymer Sci

View full text Add to dashboard Cite

Poly(vinyl alcohol) (PVA)-amino acid (AA) biocomposite membranes are prepared by blending PVA with AAs such as glycine, lysine (LY), and phenyl alanine followed by in situ crosslinking with citric acid (CA) and explored as a new class of biocomposite membrane electrolytes for direct methanol fuel cells (DMFCs). CA crosslinks with PVA through esterification offers adequate chemical, thermal, and morphological stability thereby produces methanol-obstructing close-packed polymeric network. These biocomposite membranes are characterized in terms of mechanical, thermal, sorption, and proton-conducting properties. Hydrophilic nature of AA zwitterions significantly facilitates proton conduction and CA crosslinking mitigates methanol crossover through establishing appropriate balance between hydrophilic/hydrophobic domains. The rational design of membrane microstructure with proper arrangement of hydrophobic/hydrophilic domains is a key to enhance electrochemical selectivity of PVA-AA/CA biocomposite membranes. Biocomposite membrane comprising LY exhibits nearly threefold higher electrochemical selectivity in relation to PVA/CA blend membrane.

show abstract

“…In another SPES/zirconium sulphophenylphosphonate (ZrSPP) composite system possessing packed sulfonic acids at the interfaces, a distinctive proton‐transport phenomenon, proposed as a “packed‐acid mechanism”, was observed experimentally and theoretically . At the interfaces, the H‐bonds are weakened by acid–acid interactions, giving a more‐flexible H‐bonded network and facilitating proton mobility.…”

Section: Nanostructured Polymer–filler Composite Membranesmentioning

confidence: 99%

Nanostructured Ion‐Exchange Membranes for Fuel Cells: Recent Advances and Perspectives

et al. 2015

View full text Add to dashboard Cite

Polymer-based materials with tunable nanoscale structures and associated microenvironments hold great promise as next-generation ion-exchange membranes (IEMs) for acid or alkaline fuel cells. Understanding the relationships between nanostructure, physical and chemical microenvironment, and ion-transport properties are critical to the rational design and development of IEMs. These matters are addressed here by discussing representative and important advances since 2011, with particular emphasis on aromatic-polymer-based nanostructured IEMs, which are broadly divided into nanostructured polymer membranes and nanostructured polymer-filler composite membranes. For each category of membrane, the core factors that influence the physical and chemical microenvironments of the ion nanochannels are summarized. In addition, a brief perspective on the possible future directions of nanostructured IEMs is presented.

show abstract

The proton conduction mechanism in a material consisting of packed acids

Abstract: We observed fast proton conduction in a material consisting of packed acids, the “packed-acid mechanism” resulting from acid–acid interactions.

Cited by 77 publications

References 46 publications

High proton conductivity in cyanide-bridged metal–organic frameworks: understanding the role of water

High proton conductivity in cyanide-bridged metal–organic frameworks: understanding the role of water

Biocomposite proton‐exchange membrane electrolytes for direct methanol fuel cells

Nanostructured Ion‐Exchange Membranes for Fuel Cells: Recent Advances and Perspectives

Contact Info

Product

Resources

About