Nanoscale control of composition in cerium and zirconium mixed oxide nanoparticles

The surface morphology, geometry and distribution of dopant in cerium and zirconium oxide (CZO) nanoparticles prepared by spray pyrolysis were characterized by scanning electron microscopy, transmission electron microscopy and X-ray energy dispersive spectroscopy (XEDS), respectively. By combining the XEDS analysis and concentration distribution modelling, accurate composition concentration variation within a particle can be determined. It is shown that by appropriately selecting cerium precursors, the composition distribution in CZO nanoparticles can be controlled. Linear zirconium concentration distribution in the CZO particles has been achieved, which may be important to decrease probability of zirconium segregating into clusters and to improve oxygen ion mobility for higher oxygen storage/release capacity in three-way catalysts. This control is based on the suggested mechanism of dopant distribution which proposes that hydration energies influence diffusion rates of the precursors during preparation process.