  Gadolinium-doped ceria was studied in a half SOFCs at elevated temperatures.
In situ electron holography could reveal ionic activity in a single GDC-Pt
interface at the elevated temperatures that result in further oxidation of the
GDC. In situ EELS measurements confirmed holography results and showed the
existence of the gadolinium in a new oxidation state. Also, it was found that
the doped cations are the active ions in the oxygen evolution reaction from the
solid oxide electrolyte.
