Two series of t-ZrO(2) samples doped with 5 mol% of alien Sm, Gd, Mo, Mn and V cations were synthesized by wet impregnation and calcined at 600 degrees C or 1000 degrees C for 6 h, respectively. Structural (XRD) and spectroscopic (EPR, RS) characterization was completed by reducibility studies (TPR). Low-temperature NO adsorption, monitored by EPR, was investigated to find the link between structural properties of doped zirconia and activation modes of NO molecules. Relations between the chemical composition and dopant speciation, reducibility of the catalysts and the ways of NO adsorption were elucidated. (C) 2010 Elsevier B.V. All rights reserved.