| AVS 55th International Symposium & Exhibition | |
| In Situ Microscopy and Spectroscopy: Interfacial and Nanoscale Science Topical Conference | Wednesday Sessions |
| Session IS+SY+SS-WeM |
| Session: | In Situ Spectroscopy – Interfacial Science and Catalysis |
| Presenter: | K. Adib, Corning Incorporated |
| Authors: | K. Adib, Corning Incorporated M. Backhaus-Ricoult, Corning Incorporated T.P. St. Clair, Corning Incorporated B. Luerssen, Justus Liebig Universitaet, Germany L. Gregoratti, Sincrotrone Elettra, Italy A. Barinov, Sincrotrone Elettra, Italy |
| Correspondent: | Click to Email |
We have used synchrotron based X-ray photoemission spectroscopy (XPS) and scanning photoemission microscopy (SPEM) to study the surface compositions of model solid oxide fuel cells containing LaxSr1-xMnO3 (LSM) cathode and yttrium-stabilized zirconia (YSZ) electrolyte under various oxygen pumping conditions at approximately 650°C and an oxygen partial pressure of 5x10-7 mbar. SPEM in the vicinity of the LSM/YSZ interface indicates depletion of Mn atoms from the LSM surface and their accumulation on the YSZ surface with increasing cathodic bias. XPS indicates that the accumulation of Mn on the YSZ is accompanied by reduction in the oxidation state of Mn. Within a wide range of applied voltage these changes are reversible. XPS of oxygen core levels also indicates that under cathodic bias, during which oxygen is incorporated from the surrounding gas into the cathode and pumped through the electrolyte, an additional oxygen species is present on the surface of LSM. The concentration of this species increases with increasing cathodic bias and we tentatively assign this species to surface oxygen as distinct from lattice oxygen. On the YSZ surface, no such change in the concentration of the surface oxides with cathodic bias was detected emphasizing the role of LSM in enhanced adsorption of oxygen.