Electronic structure of nanoporous ceria from x-ray absorption spectroscopy and atomic multiplet calculations

Abstract

We study the electronic structure of three-dimensional nanoporous $\mathrm{Ce}{\mathrm{O}}_{2\ensuremath{-}x}$ monoliths (aerogels) by soft x-ray absorption near-edge structure (XANES) spectroscopy. Atomic multiplet calculations are used to interpret high-resolution $\mathrm{Ce}\phantom{\rule{0.2em}{0ex}}{M}_{4,5}$- and ${N}_{4,5}$-edge XANES spectra. Results show that aerogels with thicker ligaments, but with the same average size of crystallites, exhibit larger ${\mathrm{Ce}}^{3+}$ content and, hence, higher oxygen deficiency.