Phase Transformation Dynamics in Sulfate-Loaded Lanthanide Triphosphonates. Proton Conductivity and Application as Fillers in PEMFCs

IR Salcedo and RMP Colodrero and M Bazaga-Garcia and M Lopez-Gonzalez and C del Rio and K Xanthopoulos and KD Demadis and GB Hix and AD Furasova and D Choquesillo-Lazarte and P Olivera-Pastor and A Cabeza, ACS APPLIED MATERIALS & INTERFACES, 13, 15279-15291 (2021).

DOI: 10.1021/acsami.1c01441

Phase transformation dynamics and proton conduction properties are reported for cationic layer-featured coordination polymers derived from the combination of lanthanide ions (Ln(3+)) with nitrilo- tris(methylenephosphonic acid) (H6NMP) in the presence of sulfate ions. Two families of materials are isolated and structurally characterized, i.e., Ln(2)(H4NMP)(2)(H2O)(4)(HSO4)(2)center dot nH(2)O (Ln = Pr, Nd, Sm, Eu, Gd, Tb, Er, Yb; n = 4-5, Series I) and Ln(H5NMP)SO4 center dot 2H(2)O (Ln = Pr, Nd, Eu, Gd, Tb; Series II). Eu/Tb bimetallic solid solutions are also prepared for photoluminescence studies. Members of families I and II display high proton conductivity (10(-3) and 10(-2) S.cm(-1) at 80 degrees C and 95% relative humidity) and are studied as fillers for Nafion-based composite membranes in PEMFCs, under operating conditions. Composite membranes exhibit higher power and current densities than the pristine Nafion membrane working in the range of 70-90 degrees C and 100% relative humidity and with similar proton conductivity.

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