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

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.