Synthesis and proton conduction properties of lanthanide amino-sulfophosphonates
Cabeza-Díaz, Aurelio,Bazaga-García, Montse,Pérez-Colodrero, Rosario Mercedes,Salcedo, Inés R.,Villemin, Didier,Olivera-Pastor, Pascual,Losilla, Enrique R.
- Published
- 2016
- Language
- sp
Abstract
Crystalline acid-functionalized metal phosphonates are potential candidates as proton conducting electrolytes. Their frameworks can be chemically modified to contain proton carriers such as acidic groups (P-OH; -SO3H, -COOH,…) and guest molecules (H2O, NH3,…) that generates hydrogen bond networks stable in a wide range of temperature [1,2]. In this work, focus is laid on properties derived from the combination of lanthanide ions with the amino-sulfophosphonate ligand (H2O3PCH2)2-N-(CH2)2-SO3H. Hightrough-put screening was followed to reach the optimal synthesis conditions under solvothermal conditions at 140 ºC. Isolated polycrystalline solids, Ln[(O3PCH2)2-NH-(CH2)2-SO3H].2H2O (Ln= La, Pr and Sm), crystallize in the monoclinic (La) and orthorhombic (Pr and Sm) systems with unit cell volume of ~2548 Å3. Preliminary proton conductivity measurements for Sm derivative have been carried out between 25º and 80 ºC at relative humidity (RH) values of 70 % and 95 %. The sample exhibits enhanced conductivity at high RH and T (Figure 1) and constant activation energies of 0.4 eV, typical of a Grothuss mechanism of proton.
Full text
SYNTHESIS AND PROTON CONDUCTION PROPERTIES OF LANTHANIDE AMINO-SULFOPHOSPHONATES Aurelio Cabezaa, Montse Bazaga-Garcíaa, Rosario M.P. Colodreroa, Inés R. Salcedoa, Pascual Olivera-Pastora and Enrique R. Losillaa aDepartamento de Química Inorgánica, Universidad de Málaga, Campus Teatinos s/n 29071-Málaga, Spain [email protected] Crystalline acid-functionalized metal phosphonates are potential candidates as proton conducting electrolytes. Their frameworks can be chemically modified to contain proton carriers such as acidic groups (P-OH; -SO3H, -COOH,…) and guest molecules (H2O, NH3,…) that generates hydrogen bond networks stable in a wide range of temperature [1,2]. In this work, focus is laid on properties derived from the combination of lanthanide ions with the amino-sulfophosphonate ligand (H2O3PCH2)2-N-(CH2)2-SO3H. Hightrough-put screening was followed to reach the optimal synthesis conditions under solvothermal conditions at 140 ºC. Isolated isostructural polycrystalline solids, Sm[(O3PCH2)2-NH-(CH2)2-SO3H].2H2O (Ln= Sm, Eu and Gd), crystallize in the orthorhombic system with unit volume of ~2548 Å3. Preliminary proton conductivity measurements for Sm derivative have been carried out between 25º and 80 ºC at relative humidity (RH) values of 70 % and 95 %. The sample exhibits enhanced conductivity at high RH and T (Figure 1) and constant activation energies of 0.4 eV, typical of a Grothuss mechanism of proton. Figure 1. Arrhenius plot for SmKJHKJHKJHK at different relative humidity values. References [1] Y. Gao, R. Broersen, W. Hageman, N. Yan, M. C. Mittelmeijer-Hazeleger, G. Rothenberg, S. Tanase J. Mater. Chem. A, 2015, 3, 22347–22352. [2] Cabeza, A.; Olivera-Pastor, P.; Colodrero, R. M. P. Tailored Organic-Inorganic Materials, Brunet, E., Colón, J.L., Clearfield, A., Eds.; John Wiley & Sons, Inc. 2015; Ch. 4, 137−191. 2,8 3,0 3,2 3,4 10 -7 10 -6 10 -5 10 -4 10 -3 10 -2 90 80 70 60 50 40 30 20 (S·cm -1 ) 1000/T (K -1 ) Temperature (ºC) 95%RH Ea=0.34eV Ea=0.41eV 70%RH
