Maximilian SchaubeMerkle, RotrautRotrautMerkleMaier, JoachimJoachimMaier2024-02-272024-02-272019-01-01Journal of Materials Chemistry A 7 (38): 21854-21866 (2019)https://hdl.handle.net/11420/46022The importance of point defects for oxygen surface reaction kinetics on doped ceria is demonstrated by pulsed isotope exchange. The oxygen surface exchange reaction on 20 different Gd/Pr/Tb, and Nb single and co-doped ceria samples is studied from 500-850 °C in 10-0.1% O2 atmosphere. The highest rates are measured when both oxygen vacancies and redox-active centers are available. Gd-doping leads to exchange rates which are proportional to the concentrations of Gd and oxygen vacancies. Pr-doped ceria exhibits a much stronger variation of the exchange rate-by almost five orders of magnitude from 0.6 to 20 mol% Pr doping-emphasizing the importance of redox-active centers. The equilibrium exchange rates are low for Nb, Nb/Pr, and Nb/Gd co-doped ceria, emphasizing the important role of oxygen vacancies for oxygen dissociation and incorporation. The oxygen partial pressure dependence indicates that molecular oxygen species are involved in the rate-determining step (in addition to oxygen vacancies).en2050-74882019382185421866RSCChemistryJournal Article10.1039/c9ta05908cJournal Article