The activities of CuO-CeO2-ZrO2 catalysts synthesized by four methods, e.g. sol-gel, co-precipitation, one-step impregnation, and two-step impregnation, were compared for CO removal from hydrogen-rich gas. The influence of the precipitant and calcination temperature on the catalytic activity was investigated, and a series of analytical methods, such as XRD, H-2-TPR, TG-DSC, and SEM, were used to characterize the catalysts. It was indicated that CuO-CeO2-ZrO2 catalyst prepared by co-precipitation method exhibits the widest operation temperature range with the 99% conversion of CO and relatively high selectivity. The optimized preparation conditions were confirmed using Na2CO3 as a precipitant, and calcining at 500 degrees C. It was proposed that the high activity and selectivity result from the high dispersion of copper and strong interaction among CuO, CeO2, and ZrO2. The effects of precipitants on the grain size and morphology of the catalyst is larger than that of calcination temperature. (c) 2006 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.