The main factors influencing the O vacancy formation on the Ir doped ceria surface: A DFT+U studyZ. X. Yang, D. W. Ma, X. H. Yu and K. HermanssonEur. Phys. J. B, 77 3 (2010) 373-380DOI: https://doi.org/10.1140/epjb/e2010-00295-x