Catalysts using platinum pre-formed nanoparticles were prepared as a strategy to evaluate the impact of structural and electronic properties of ceria-alumina-supports in the water gas shift reaction, minimizing variations of the metallic phase among samples. Promoted cerium Pt/Al2O3 catalysts, with 12 or 20 wt% of CeO2, were prepared by adding cerium precursor during the sol-gel synthesis of Al2O3 (GEL samples) or by impregnating it on the Al2O3 support (IMP samples). The presence of cerium in PtAl catalysts increases up to seven times the reaction rates and although the results showed significant impact of the preparation method on the structural and surface properties of ceria, the main dependence of the catalytic activity seems to be with the cerium loading. The results suggest the participation of interfacial Pt-O-Ce sites as the crucial contribution to the significant increases of specific reaction rate. (C) 2016 Elsevier B.V. All rights reserved.