The use of colloidal metallic nanoparticles (NPs) in catalysis is an interesting strategy to address complex and fundamental aspects in this field. This synthesis methodology allows an accurate adjustment of size and shape of the metal phase, which can reveal the complex interplay of several factors that usually determine the overall catalytic activity. In the case of bimetallic NPs, another parameter can be finely tuned, namely the composition. The full potential of colloidal NPs in catalysis is indeed extremely exciting; however, crucial aspects related to the removal of the organic protective agents, in order to expose the catalytic sites, as well as the potential drawbacks of remaining synthesis residues on the surface of the NPs have still to be deeply understood. In this work, we evaluated the effect of pretreatments on the activation of AuCu alloy NPs supported on SiO2 applied to catalytic oxidation of CO, showing their significant impact in the final performance and stability of the catalyst. (C) 2016 Elsevier B.V. All rights reserved.2821051108th International Symposium on Advanced Catalytic MaterialsAUG 17-20, 2015Cancun, MEXICO