Pr³⁺ surface fraction in CePr mixed oxides determined by XPS analysis

Highlights: • Pr 3d XPS spectra of CePr samples were submitted to a deconvolution procedure. • By considering a previous peak assignment, the Pr³⁺ surface fraction was obtained. • Pr³⁺ surface fraction was higher than Ce³⁺, as it was suspected in previous work. - Abstract: CePr mixed oxides were previously studied as supports for Water Gas Shift catalysts, considering their promising textural and redox properties arising from the presence of a non-stoichiometric oxide. A very small Ce³⁺ fraction was observed on those oxides, suggesting that Pr³⁺ion could be responsible for the enhanced activity. Therefore, in-depth XPS analysis is conducted in the present work in order to determine the Pr³⁺ fraction by fitting the XPS Pr 3d region. Much higher values of reduced Pr ions than Ce ions were observed, confirming the promoter role of the former.