Investigation of metastable phases in zirconia-ceria nanoceramics by synchrotron X-ray powder diffraction

Synchrotron X-ray powder diffraction (SXPD) is a powerful tool for the investigation of the crystal structure of materials. Several examples can be found in the literature exploiting the high-resolution of SXPD setups in order to separate overlapped Bragg peaks. Differently, in the present work, we tool advantage of the high-density of the synchrotron radiation to detect very weak Bragg reflections. These experiments were carried out using the high-intensity (low resolution) configuration on the X-ray diffraction beamlines at the LNLS By this procedure, we were able to study the crystal structure of nano structured zirconia-ceria (ZrO2-CeO2) solid solutions, identifying the metastable forms of the tetragonal phase of these materials, which have important technological applications in different areas such as the control of NOx, CO and hydrocarbons emissions from automotive exhausts, and Solid-Oxide Fuel Cells operated with hydrocarbons. (author)