Platinum on ceria-zirconia (CZO) catalysts for the water-gas shift (WGS) reaction were prepared with various platinum loadings. in addition, the activity of Pt/CZO catalysts was tested preliminarily at gas hourly space velocity (GHSV) of 5000 h(-1). Activity tests were also conducted at GHSV of 200,000 h(-1) with limited conversions, and activation energies and pre-exponential factors for rate equations were obtained by fitting the data. The effectiveness factors were estimated on the basis of the intra-particle mass transfer. Moreover, with this estimation, an attempt was made to calculate the utilization of the Pt loading with an eggshell morphology. (C) 2008 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.