Local Structures around Ce Atoms in CeO2-Stabilized Tetragonal ZrO2

Local structure and nanoscale homogeneity of CeO2-ZrO2: differences and similarities to parent oxides revealed by luminescence with temporal and spectral resolution.

Although homogeneity at the atomic level of CeO2-ZrO2 with a Ce/Zr atomic ratio close to unity is considered to be one of the main causes for the increased total oxygen storage capacity (OSC), the characterization approaches of homogeneity remain a major challenge. We propose a simple, yet effective method, to assess both structural and compositional homogeneity of CeO2-ZrO2 by using Eu(3+) lum...

Surface chemistry of pure tetragonal ZrO2 and gas-phase dependence of the tetragonal-to-monoclinic ZrO2 transformation.

The surface chemical properties of undoped tetragonal ZrO2 and the gas-phase dependence of the tetragonal-to-monoclinic transformation are studied using a tetragonal ZrO2 polymorph synthesized via a sol-gel method from an alkoxide precursor. The obtained phase-pure tetragonal ZrO2 is defective and strongly hydroxylated with pronounced Lewis acidic and Brønsted basic surface sites. Combined in s...

Do Au Atoms Titrate Ce Ions at the CeO2−x(111) Surface?

Ce sites may play an important role in defining active sites in ceria-based catalysis. Yet, though present at the catalyst surface, their positions have not been experimentally observed. Recently, it has been argued that Ce sites are the preferred location for the binding of Au− species on a highly reduced CeO2(111) surface with subsurface oxygen defects. Hence, Au atoms have been proposed as t...

Structure Analysis of CeO2-ZrO2 Mixed Oxides as Oxygen Storage Promoters in Automotive Catalysts

Oxygen storage/release (OSC) capacity is an important feature common to all three-way catalysts that enables them to efficiently remove harmful compounds such as hydrocarbons, CO and NOx in automotive exhaust gases. In this report, three types of CeO2-ZrO2 (Ce:Zr = 1:1 molar ratio) compounds with different OSC were characterized by means of XRD (X-ray diffraction) and XAFS (X-ray absorption fin...

Ce K-EDGE EXAFS SPECTRUM OF CeO2