Surface Properties and Physicochemical Characterizations of a New Type of Anode Material, La_1−xSr_xCr_1−yRu_yO_3−δ, for a Solid Oxide Fuel Cell under Methane at Intermediate Temperature

Anne-Laure Sauvet (1) , Jacques Fouletier (1) , F. Gaillard (2) , M. Rimet (2)

1 LEPMI - Laboratoire d'Electrochimie et de Physico-chimie des Matériaux et des Interfaces
2 LACE - Laboratoire d'Application de la Chimie à l'Environnement

In order to develop a new anodic material for a solid oxide fuel cell (SOFC) operated under methane, we studied lanthanum chromites doped with strontium and ruthenium. Ruthenium is an excellent catalyst for methane steam reforming but its use is limited by its cost and evaporation as RuO_x at high temperature. To stabilize the ruthenium, we inserted it into the perovskite to form La_1−xSr_xCr_1−yRu_yO₃. XRD, SEM, TPR, and EDX analyses revealed the stability of ruthenium in the perovskite, in the tetravalent state. The composition was homogeneous in the entire volume of the electrode. Nevertheless, XPS analyses indicated a strontium segregation for a thickness lower than 5 nm. The EDX analyses also showed a strontium concentration gradient near the subsurface. The main result was that no loss of ruthenium was detected even after treatments under air at 1100°C. The strontium doping allows the stabilization of the ruthenium in the perovskite in the tetravalent state.

Mots clés: perovskite; ruthenium; XPS; TPR; methane reforming; catalytic activity

Domaines: Matériaux

Anne-Laure Sauvet, Jacques Fouletier, F. Gaillard, M. Rimet. Surface Properties and Physicochemical Characterizations of a New Type of Anode Material, La_1−xSr_xCr_1−yRu_yO_3−δ, for a Solid Oxide Fuel Cell under Methane at Intermediate Temperature. Journal of Catalysis, 2002, 209 (1), pp. 25-34. ⟨10.1006/jcat.2002.3588⟩. ⟨hal-00418101⟩