NMR Investigations of the Protonic Transport Mechanism in Composed Materials on the Basis of Cesium Acid Sulfates and Phosphates

作者：Chernyak Alexander V^*; Volkov Vitaly I

来源：Applied Magnetic Resonance, 2014, 45(3): 287-299.

DOI：10.1007/s00723-014-0520-z

The composite materials Cs(HSO4)(1-x) (H2PO4) (x) were investigated by X-ray phase analysis, differential scanning calorimetry, nuclear magnetic resonance (NMR) relaxation, pulsed field gradient NMR (PFG-NMR) and impedance spectroscopy. Three composite materials types x = 0.1 A center dot 0.3 mixture CsHSO4, alpha-Cs-3(HSO4)(2)(H2PO4), beta-Cs-3(HSO4)(2.5)(H2PO4)(0.5)-compositions of area I; x = 0.4 A center dot 0.5 mixture alpha-Cs-3(HSO4)(2)(H2PO4) and Cs-2(HSO4)(H2PO4)-compositions of area II; x = 0.6 A center dot 0.9 mixture Cs-2(HSO4)(H2PO4) and CsH2PO4-compositions of area III, were synthesized. The phase transition temperature from the low-to-high conductive phase for obtained composite materials is notably below (about 100 A degrees C) than that for the individual components. The proton self-diffusion coefficients measured by PFG-NMR are lower than the diffusion coefficients calculated from proton conductivities data. The correlation times tau (d) controlling the P-31-H-1 magnetic dipole-dipole interaction were calculated according to data of the spin-lattice relaxation on P-31 nuclei. The self-diffusion coefficients estimated from the Einstein equation are in good agreement with the experimental self-diffusion coefficients measured by PFG-NMR. It confirms the fact that the proton mobility is caused by the rotation of PO4 anion tetrahedra.

• 出版日期2014-3