Time resolved DXAS study on micro and nano NiO/Ce0. 9Gd0. 1O1. 95 cermets for intermediate temperature solid oxide fuel cells

摘要: We present a crystallographic, morphologic and redox dynamic study on (60: 40) NiO/Ce0. 9Gd0. 1O1. 95 (NiO/GDC) cermets simulating Intermediate Temperature Solid Oxide Fuel Cells (IT-SOFC) anodes in situ conditions. We tested micro-and nanometer sized materials at 700ºC in three different atmospheres (5% H2, 5% O2 and 20% CH4). We used Dispersive X-ray Absorption Spectroscopy (DXAS) analysis at the Ce L3-edge and at the Ni K-edge to follow the metals oxidation states. A correlation between the catalytic/redox properties and the samples characteristics (microstructure, Ni distribution, etc.) was found, indicating that nanometric sized particles showed faster and higher reduction extents than micrometric particles of the same composition.