Anhydrous Superprotonic Conductivity in the Zirconium Acid Triphosphate ZrH5(PO4)3**

Funding Information: S.F. gratefully acknowledges the Ramsay Memorial Trust and the University of Aberdeen's School of Natural and Computing Sciences for the provision of a Ramsay Memorial Fellowship. This paper benefited from the insights of Professor Giulio Alberti who was a pioneer and one of the most authoritative scientists of the chemistry of M phosphates and phosphonates. IVPeer reviewedPublisher PD

Dynamic nuclear polarisation NMR of nanosized zirconium phosphate polymer fillers

International audience; Surface functionalisation with organic modifiers of multi-layered zirconium phosphate (ZrP) nanoparticles used as polymer fillers can be directly probed by dynamic nuclear polarisation NMR, which provides unambiguous evidence of the presence of P-O-C chemical bonds at the surface of the ZrP layers, thereby confirming successful functionalisation

Anhydrous Superprotonic Conductivity in the Zirconium Acid Triphosphate ZrH5(PO4)3

The development of solid-state proton conductors with high proton conductivity at low temperature is crucial for the implementation of hydrogen-based technologies for portable and automotive applications. Here, we report on the discovery of a new crystalline tetravalent metal acid triphosphate, ZrH5(PO4)3 (ZP3), which exhibits record-high proton conductivity of 3.0 x 10-2 S cm-1 at 110 °C in anhydrous conditions. Structural characterization and bond-valence sum energy (BVSE) calculations reveal the pathways and mechanism of proton transport. Extended defective hydrogen bond chains, where the protons are dynamically disordered over two oxygen centers, enable fast ionic diffusion with minimal activation energy for proton hopping

Survey on the Phase Transitions and Their Effect on the Ion-Exchange and on the Proton-Conduction Properties of a Flexible and Robust Zr Phosphonate Coordination Polymer

The flexible zirconium tetraphosphonate coordination polymer with formula Zr­(O₃PCH₂)₂N-C₆H₁₀-N­(O₃CH₂P)₂X_2–<i>x</i>H_2+<i>x</i>·<i>n</i>H₂O (X = H, Li, Na, K, 0 < <i>x</i> < 1, 4 < <i>n</i> < 7.5) (<b>1</b>) possesses an open framework structure with 1D cavities decorated with polar and acids PO and POH groups. <b>1</b> has been fully protonated by adding HCl and then subjected to several acid–base ion-exchange reactions with alkaline metals hydroxides. <b>1</b> is a very robust coordination polymer because it can be regenerated in H- form using strong acid solutions and ri-exchanged several times without hydrolysis and loss of crystallinity. The flexibility of <b>1</b> has been also studied by means of TDXD (temperature dependent X-ray diffraction) evidencing remarkable phase transformations that lead to a different disposition of the water molecules. These transformations also influence the accessibility of the cations on the P–OH groups placed inside the channels and thus the ion-exchange properties. The dependence of the proton conductivity properties on these phase transitions has been also investigated and discussed

Survey on the Phase Transitions and Their Effect on the Ion-Exchange and on the Proton-Conduction Properties of a Flexible and Robust Zr Phosphonate Coordination Polymer

The flexible zirconium tetraphosphonate coordination polymer with formula Zr­(O₃PCH₂)₂N-C₆H₁₀-N­(O₃CH₂P)₂X_2–<i>x</i>H_2+<i>x</i>·<i>n</i>H₂O (X = H, Li, Na, K, 0 < <i>x</i> < 1, 4 < <i>n</i> < 7.5) (<b>1</b>) possesses an open framework structure with 1D cavities decorated with polar and acids PO and POH groups. <b>1</b> has been fully protonated by adding HCl and then subjected to several acid–base ion-exchange reactions with alkaline metals hydroxides. <b>1</b> is a very robust coordination polymer because it can be regenerated in H- form using strong acid solutions and ri-exchanged several times without hydrolysis and loss of crystallinity. The flexibility of <b>1</b> has been also studied by means of TDXD (temperature dependent X-ray diffraction) evidencing remarkable phase transformations that lead to a different disposition of the water molecules. These transformations also influence the accessibility of the cations on the P–OH groups placed inside the channels and thus the ion-exchange properties. The dependence of the proton conductivity properties on these phase transitions has been also investigated and discussed

Effects of water freezing on the mechanical properties of nafion membranes

Most of the research efforts on Nafion have been devoted to the study of the perfluorinated ionomer membranes at optimal conditions for the desired applications, such as high temperature and low relative humidity for polymer electrolyte membrane fuel cells (PEM FC). In view of the possible changes induced by the freezing of water in the structure of Nafion and considering that in cold start conditions of a PEM FC device, Nafion needs to work also below 273 K, we measured the Young's modulus (Y) and the elastic energy dissipation (tan d) in the temperature range between 90 and 470 K and the stressstrain curves between 300 and 173 K. The measurements reported here indicate that the mechanical properties of wet Nafion membrane change dramatically with temperature, that is, from a rubber-like behavior at room temperature to a brittle behavior below 180 K. Moreover, we observed that the freezing of the nanoconfined water is complete only below 180 K, as indicated by a large increase of the Young's modulus. Between 180 and 300 K, the large values of tan d suggest the occurrence of friction between the liquid water bound to the walls of the hydrophilic domains and the solid ice residing in the center of channels. (c) 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 201

Promising aquivion omposite membranes based on fluoroalkyl zirconium phosphate for fuel cell applications

International audienc

Versatile Micrielectrode Assembly for Nanosecond Pulse Delivery to Cell Suspensions

International audienc

Investigating the Effect of Positional Isomerism on the Assembly of Zirconium Phosphonates Based on Tritopic Linkers

We report on the use of a novel tritopic phosphonic linker, 2,4,6-tris[3-(phosphonomethyl)phenyl]-1,3,5-triazine, for the synthesis of a layered zirconium phosphonate, named UPG-2. Comparison with the structure of the permanently porous UPG-1, based on the related linker 2,4,6-tris[4-(phosphonomethyl)phenyl]-1,3,5-triazine, reveals that positional isomerism disrupts the porous architecture in UPG-2 by preventing the formation of infinitely extended chains connected through Zr-O-P-O-Zr bonds. The presence of free, acidic P-OH groups and an extended network of hydrogen bonds makes UPG-2 a good proton conductor, reaching values as high as 5.7x10-4 S cm-1.<br /