INVESTIGADORES
CANEIRO Alberto
congresos y reuniones científicas
Título:
Studies on La2Mo2O9-d Oxide-ion Conductor under Reducing Atmospheres
Autor/es:
J. VEGA CASTILLO; U. RAVELLAC; G. CORBEL; L. MOGNI; PH. LACORRE; A. CANEIRO
Lugar:
Zaragoza
Reunión:
Congreso; Fuel Cell 2010-Grove Conference; 2010
Institución organizadora:
Editorial Elsevier
Resumen:
La2Mo2O9 is a fast oxide-ion conductor reported in recent years [1]. Its applicability as electrolyte for IT-SOFCs is limited by exhibiting a phase transition around 580ºC and presenting poor stability under reducing atmospheres [2].  The partial reduction of La2Mo2O9 at temperatures around 750ºC, may lead to the phase transformation to the perovskite-related La7Mo7O30 compound whose electrical properties have not been studied yet. A further reduction at 600<T<800ºC, leads to the amorphization with the apparition of significant electronic conductivity [3].This work presents several TGA experiments on La2Mo2O9 in controlled pO2 reductive atmospheres and some experimental approaches to densify and to characterize the electrical properties of the reduced phases, specially the amorphous La2Mo2O6.5±y due to its potential applicability as anode for SOFCs [4]. The reduction profile of La2Mo2O9-d varies depending on temperature, amount of sample and the atmosphere. When the reduction takes place at temperatures around 600ºC, the material losses oxygen directly from 9 to 6.5±y with y~0.4, and the result is an amorphous compound. At 718<T<760ºC, the reduction in N2-H2 curve shows and intermediate plateau at an oxygen content of 8,57 corresponding to La7Mo7O30. It is also possible to obtain this phase in thermodynamic equilibrium by controlling the pO2 in the atmosphere at a value of 10-20atm at 718ºC. The main drawback to characterize the electrical properties of La7Mo7O30 and amorphous La2Mo2O6.5±y is the difficulty to sinter high density samples of them, this due to their short stability range in temperature. Different attempts of getting dense samples and electrical characterizations were made. The results suggest significantly high electronic conductivity in amorphous La2Mo2O6.5±y and interesting properties as anode material for SOFCs. References: [1]. Ph. Lacorre, F. Goutenoire, O. Bohnke, R. Retoux and Y. Laligant, Nature 404 (2000) 856.[2]. D. Marrero-López, J. Canales-Vázquez, J.C. Ruiz-Morales, J.T.S. Irvine, P. Núñez, Electrochimica Acta 50 (2005) 4385. [3] J. Vega-Castillo, L. Mogni, G. Corbel, P. Lacorre, A. Caneiro, International Journal of Hydrogen Energy (2010), Article in press. [4]. X. C. Lu and J. H. Zhu, J. Electrochemical Soc. 155 (2008) 1053.