Synthesized by impregnation and coprecipitation methods, ceria-supported copper samples were tested in catalytic decomposition of N2O (deN(2)O) under dry and wet conditions. Basing on the structural (XRD, SEM), spectroscopic (EPR, RS) and catalytic characterization, supported by DFT calculations, the role of mono- and dimeric copper as active centers in the deN(2)O reaction was evaluated. Particular attention was paid to elucidation of the structure and localization of the Cu2+-Cu2+ pairs within the CeO2 matrix, their stability and chemical conditions of their formation. (c) 2012 Elsevier B.V. All rights reserved.