Controlling Reduction Kinetics in the Galvanic Replacement Involving Metal Oxides Templates: Elucidating the Formation of Bimetallic Bowls, Rattles, and Dendrites from Cu2O Spheres

This study demonstrates that the precursor reduction kinetics can be employed to control the morphology and composition of bimetallic metal/metal oxides systems obtained by galvanic replacement reaction using metal oxides as sacrificial templates. This work investigated Cu2O as a proof-of-concept example, in which the relative rates of Cu2O oxidation by O2 and by noble metal precursors determined the morphology and composition of the products. We focused on three metal precursors with fast, medium, and slow reduction kinetics in the presence of Cu2O under aerobic conditions: PdCl42–, AuCl4–, and Ru3+, respectively. It was found that metal-oxide-based bowls, rattles, or dendrites can be obtained by simply changing the precursor reduction kinetics. These results provide novel insights over the versatility and mechanistic understanding of galvanic replacement to the synthesis of metal/metal-oxide bimetallic nanoparticles.