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87 STRUCTURAL STUDY OF THE LOCAL ORDER IN AMMONIAMODULATED FE(II) HYDROXYPHOSPHONOACETATE PROTON CONDUCTORS M. Bazaga-Garcíaa, A. Cabezaa, R.M.P. Colodreroa, I.R. Salcedoa, P. OliveraPastora and E.R. Losillaa a Departamento de Química Inorgánica, Cristalografía y Mineralogía, Facultad de Ciencias, Campus de Teatinos s/n, Universidad de Málaga, 29071 Málaga (Spain); m.baza[email protected] Layered Fe(II) carboxiphosphonate, Fe-HPAA·2H2O1, is a crystalline multifunctional coordination polymer exhibiting properties as photocatalyst2 and proton conductor. Postsynthesis modification by ammonia/water adsorption3 strongly enhances its proton conductivity. However, this process entails a progressive amorphization but in no case intercalation of the guest species was detected. Understanding the mechanism involved in this increased conductivity is crucial to develop novel high performance proton conductors for PEMFCs. Thus, total scattering and PDF study has been carried out to explore the mechanism of ammonia adsorption and subsequent amorphization. Different lenght scales have been investigated to characterize the average and local structure at variable ammonia loaded in order to ascertain posible structural modifications after gas/solid reactions. While significant short range order (from 1.4 to 10 Å) variations were observed even for low loadings, the average structure seems to be basically preserved except for the highest ammonia/water contents. Figure 1 . Radial distribution functions for FeHPAA exposed to NH 3 gas at several times (0h black, 36h red, 48h blue and 72h green) Acknowledgements. The work at UMA was funded by MAT2016-77648-R, MAT201341836-R (MINECO, Spain) and FQM-1656 (Junta de Andalucía) research grants and CELLSALBA Synchrotron is thanked for the provision of synchrotron X-ray beamtime at BL04MSPD. 1 R. Fu, S. Xiang, H. Zhang, J. Zhang, and X. Wu, Cryst. Growth Des.2005, 5, 1795-1799. 2 M Bazaga-García, A. Cabeza, P. Olivera-Pastor, I. Santacruz, R. M. P. Colodrero, and M. A. G. Aranda, J. Phys. Chem. C 2012, 116, 14526−14533. 3 M. Bazaga-García, R. M. P. Colodrero, M. Papadaki,‡ P. Garczarek, J. , P Olivera-Pastor, E. R. Losilla, L. -Reina, M. A. G. Aranda, D. Choquesillo-Lazarte, K. D. Demadis and A. Cabeza ,J. Am. Chem. Soc. 2014, 136, 5731−5739. 2 3 4 5 6 7 8 9 10 r ( Å ) 30 35 40 45 50 55 60 r ( Å ) Poster Contributions P-29
