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

Abstract 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: , , 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.