RT Journal Article
T1 Impact of the lanthanide size on the polymorphism and electrical properties of Ln5.4MoO11.1 (Ln = Nd, Sm and Gd)
A1 Rubio-Vives, Rafael
A1 Porras-Vázquez, José Manuel
A1 Dos-Santos-Gómez, Lucía
A1 Zamudio-García, Javier
A1 Infantes-Molina, Antonia
A1 Canales-Vázquez, J.
A1 Marrero-López, David
A1 Ramírez-Losilla, Enrique
K1 Metales de las tierras raras
AB Mixed proton-electronic conductors are of great interest for high temperature electrochemical devices, such ashydrogen separation membranes. In this contribution, ceramics with composition Ln5.4MoO11.1 (Ln = Nd, Smand Gd) were prepared by a freeze-drying precursor method. The resulting powders were sintered at 1500 ◦C andcooled down at different rates to investigate the different polymorphic forms: quenching (rapid cooling), 5 and0.5 ◦C min-1. The ceramics were characterized by different techniques: X-ray diffraction, scanning and transmissionelectron microscopies and X-ray photoelectron and impedance spectroscopies. X-ray diffraction studiesconfirmed that all materials are single phase regardless of the cooling rate used. Those cooled by quenchingpresent a simple cubic fluorite structure. At lower rates, 5 and 0.5 ◦C min-1, the cubic symmetry is stabilized asthe size of the lanthanide decreases. However, electron diffraction studies indicated the formation of domainswith superstructure ordering. Furthermore, XPS analysis showed the presence of mixed Mo6+ and Mo5+ for allcompositions, which explains the electronic conduction in an oxidizing atmosphere. All materials are stable inreducing atmosphere and the ionic and electronic conductivities show opposite trends as the ionic radii of thelanthanide element becomes smaller, where the former decreases and the latter increases.
PB Elsevier
YR 2023
FD 2023
LK https://hdl.handle.net/10630/28446
UL https://hdl.handle.net/10630/28446
LA eng
DS RIUMA. Repositorio Institucional de la Universidad de Málaga
RD 21 ene 2026