Exceptional capability of nanosized CeO2 materials to “dissolve” lanthanide oxides established by time-gated excitation and emission spectroscopy

Abstract

The atomic scale homogeneity of Ce and Zr oxygen bonds represents the main reason for enhanced total oxygen storage capability of CeO₂–ZrO₂ (Ce/Zr = 1) as compared to that of CeO₂. Here, we demonstrate that the addition of 10% Eu³⁺ by wet impregnation on preformed nanosized CeO₂–ZrO₂ (Ce/Zr = 1) followed by calcination induces a remarkable homogeneity of 10% Eu³⁺–CeO₂–ZrO₂ solid solution. By use of time-resolved emission and excitation spectroscopies, the improvement of the nanoscale chemical and structural homogeneity of 10% Eu³⁺–CeO₂–ZrO₂ calcined at 1000 as compared to sample calcined at 750 °C is demonstrated. Based on the comparison of luminescence properties of 10% Eu³⁺ impregnated on preformed nanosized CeO₂–ZrO₂ and CeO₂, we also show that the presence of zirconium does not only preserve the ability of cerium oxide to “dissolve” lanthanide oxide, but also determines an important stabilization of defects (oxygen vacancies) generated upon Eu³⁺ doping.