Platinum nanoparticles were dispersed by wet impregnation on YSZ (8 mol% Y2O3) an ionically conducting support. The Pt dispersion of a series of catalysts was determined by using H-2 pulse chemisorption. Temperature Programmed Reduction (TPR) experiments were performed to characterize the pre-reduction step before dispersion measurements. Finally, a fast and reliable procedure was defined for the Pt dispersion measurements consisting in a pre-reduction step in hydrogen at 500 degrees C before the H-2 pulse chemisorption performed at -28 degrees C. Reproducible Pt dispersion values were obtained in good agreement with those measured by pulse CO chemisorptions and static volumetric titration. In addition, the combination of Diffuse Reflectance Infrared Fourier Transform (DRIFT) spectroscopy and TPR has evidenced the role of surface oxygen vacancies on YSZ support for both H-2 and CO chemisorptions. (C) 2011 Elsevier B.V. All rights reserved.