Bimetallic nanoalloys: polymer-assisted preparation and catalytic properties

Bimetallic nanoparticles (NPs) are potential candidates for application in many fields - in particular catalysis. In the last years, CoPd as well as AuAg NPs have gained notable attention due to significantly enhanced catalytic performances as compared to the respective monometallic ones. For that purpose, monodisperse CoPd and AuAg NPs of well-controlled composition was achieved here by the polyol method using polymer PVP as stabilizing agent as well as using reverse micelles of a block copolymer as nanoreactors. In contrast to classical methods, both colloidal approaches applied here, can achieve systematic and independent control over NP size and composition. Significant benefits caused by addition of a second metal in both case could be clearly demonstrated in reduction and oxidation reactions in liquid (quasi-homogeneous catalysis) and gas phase (heterogeneous catalysis), respectively. Besides, effects caused by NP size, composition and support could be separately investigated.