A New Solid-State Proton Conductor: The Salt Hydrate Based on Imidazolium and 12-Tungstophosphate
Anna Martinelli, José M. Otero-Mato, Mounesha N. Garaga, Khalid Elamin, Seikh M. H. Rahman, Josef W. Zwanziger, Ulrike Werner‐Zwanziger, Luis M. Varela
Abstract
= 0.26 eV), attributed to structural diffusion of protons. From complementary X-ray diffraction data, vibrational spectroscopy, and solid-state NMR experiments, the local structure of this salt hydrate was resolved, with imidazolium cations preferably orienting flat on the surface of the tungstophosphate anions, thus achieving a densely packed solid material, and water molecules of hydration that establish extremely strong hydrogen bonds. Computational results confirm these structural details and also evidence that the path of lowest energy for the proton transfer involves primarily imidazole and water molecules, while the proximate Keggin anion contributes with reducing the energy barrier for this particular pathway.