LAUSR

The reduced structure with oxygen vacancy ordering has been identified as the CeO1.68 (C-Ce2O3+δ) phase via high-resolution TEM (HRTEM). Figure 1 gives the HRTEM images from the same SDC grain projected along different orientations. While the insets are simulated images using standard CeO1.68 structure, which match the experimental ones pretty well. The reduction of Ce to Ce has been monitored by electron energy-loss spectroscopy. The decreased electronic conductivity of the SDC is revealed by electron holography, as positive electrostatic charges accumulated at the surfaces of SDC grains under electron beam irradiation, but not at CeO2 grains.