Comparison of the effects of the catalyst preparation method and CeO₂morphology on the catalytic activity of Pt/CeO₂catalysts for the water-gas shift reaction

In this study, the effects of the catalyst preparation method and CeO2 particle morphology of Pt/CeO2 catalysts for the water-gas shift reaction are compared. CeO2 supports having nanorod and nanocube morphologies were prepared. Over both types of supports, 1 wt% Pt was loaded via either the incipient wetness impregnation (IWI) method or the strong electrostatic adsorption (SEA) method. In total, four types of Pt/CeO2 catalysts were prepared, and these were characterized using various techniques and tested for the water-gas shift reaction. The cube-shaped-CeO2-based catalysts showed higher catalytic activities than the rod-shaped-CeO2-based catalysts due to the higher dispersion of Pt0 regardless of the catalyst preparation method. From the viewpoint of the catalyst preparation method, the IWI-prepared catalysts showed higher catalytic activity than the SEA-prepared catalysts regardless of the morphology of CeO2 because of the larger amount of oxygen vacancies induced by the strong interaction between PtOx and CeO2. These results highlight the fact that the catalyst preparation method and the morphology of the CeO2 support strongly affect the key factors (Pt0 dispersion and number of oxygen vacancies) separately, which are directly related to the catalytic activity in the water-gas shift reaction. It also confirms that both key factors should achieve high values to attain high catalytic activity.