We present a study of Y2-xZnxRu2O7 pyrochlores as a function of the Zn doping level x. X-ray diffraction measurements show that single-phase samples could be obtained for x < 0.2. Within the allowed range for x, dc conductivity measurements revealed a sizable decrease in resistivity at all the investigated temperatures for Zn doped samples with respect to undoped ones. Neutron diffraction data of the x = 0.2 sample showed that replacing Y3+ by Zn2+ does not result in the formation of oxygen vacancies. X-ray photoemission spectroscopy measurements revealed that part of the Ru ions are in the 5+ oxidation state to balance, in terms of electronic charge, the incorporation of Zn2+. The results give experimental evidence that the heterovalent doping promotes the increase of conductivity in the Y2Ru2O7 pyrochlores, making these systems promising as intermediate-temperature solid oxide fuel cell cathodes.
Berti, G., Sanna, S., Castellano, C., Van Duijn, J., Ruiz-Bustos, R., Bordonali, L., et al. (2016). Observation of Mixed Valence Ru Components in Zn Doped Y2Ru2O7 Pyrochlores. JOURNAL OF PHYSICAL CHEMISTRY. C, 120(22), 11763-11768 [10.1021/acs.jpcc.5b12411].
Observation of Mixed Valence Ru Components in Zn Doped Y2Ru2O7 Pyrochlores
SANNA, SAMUELE;
2016
Abstract
We present a study of Y2-xZnxRu2O7 pyrochlores as a function of the Zn doping level x. X-ray diffraction measurements show that single-phase samples could be obtained for x < 0.2. Within the allowed range for x, dc conductivity measurements revealed a sizable decrease in resistivity at all the investigated temperatures for Zn doped samples with respect to undoped ones. Neutron diffraction data of the x = 0.2 sample showed that replacing Y3+ by Zn2+ does not result in the formation of oxygen vacancies. X-ray photoemission spectroscopy measurements revealed that part of the Ru ions are in the 5+ oxidation state to balance, in terms of electronic charge, the incorporation of Zn2+. The results give experimental evidence that the heterovalent doping promotes the increase of conductivity in the Y2Ru2O7 pyrochlores, making these systems promising as intermediate-temperature solid oxide fuel cell cathodes.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.