Preparation and characterization of high surface area niobia, ceria-niobiaand ceria-zirconia

Niobia, zirconia, ceria-niobia and ceria-zirconia oxide nanoparticles are p repared by soft chemical routes and show valuable textural properties, The pore volume and specific surface area keep significant values even after ca lcination at 873 K. According to DRX and STEM-EDX measurements, solid solut ions are obtained in the case of ceria-zirconia, whereas separate phases ar e identified in ceria-niobia; in the latter case, however, W-Vis diffuse re flectance spectroscopy shows also the formation of defects (color centers) arising from a partial dissolution at the interface of the oxide phases. (C )2000 Elsevier Science B.V. All rights reserved.