On the thermodynamic stability of La2Mo2O 9-δ oxide-ion conductor

J. VEGA CASTILLO; L. MOGNI; G. CORBEL; P. LACORRE; A. CANEIRO

INTERNATIONAL JOURNAL OF HYDROGEN ENERGY

PERGAMON-ELSEVIER SCIENCE LTD

Lugar: Amsterdam; Año: 2010 vol. 35 p. 5890 - 5894

0360-3199

The stability of La2Mo2O9d oxide-ion conductor was studied under Ar–H2 and controlledoxygen partial pressure ( pO2) atmospheres within the range 608 T 1000 C, by thermogravimetry(TG), X-ray Diffraction (XRD), Temperature Controlled X-ray Diffraction(TCXRD) and Scanning Electron Microscopy (SEM).At 608 C under Ar–H2 flowing atmosphere, La2Mo2O9 phase was found to be unstable andreduction leads to an amorphous phase with composition close to La2Mo2O6.88. The stabilityof this amorphous phase under Ar–H2 was analyzed by TCXRD and found to be stable below900 C. Isothermal TG under controlled pO2 at 1000 C indicated that La2Mo2O9d is not stablebelow 107 Pa and decomposition took place without the formation of La7Mo7O30 oramorphization.