Bimetallic nanostructures with well-defined surface facets are attractive catalytic materials for experimental model studies due to the ability to systematically tailor surface atomic arrangement and the synergistic interactions between different metals, both of which influence activity and selectivity. In particular, structures with a more noble core metal and a dilute surface coverage of a more reactive metal can be used to improve product selectivity by tuning the binding strength of precursor molecules and intermediates on the catalyst surface. However, the design of such materials still proves challenging because target compositions, which mix metals such as Au and Ag with Pt, Pd, or Cu, can have unfavorable reduction potentials coupled with significant lattice mismatch. To overcome these challenges, we show that self-limiting overpotential deposition may be employed to couple Au and Pt in bimetallic nanoparticles, while simultaneously harnessing the well-understood chemistry of Au nanoparticle formation to control particle shape and surface faceting. This approach enables the formation of Au@Pt core-shell nanostructures with smooth Pt surfaces as well as tunable surface facets and compositions. In addition, we report bimetallic systems of Au and Cu which employ underpotential deposition as a mechanism to link dissimilar reduction kinetics, and methods for directing growth by limiting galvanic exchange in systems of Pd and Cu.

Approaches for bridging dissimilar reduction kinetics in the synthesis of bimetallic nanomaterials

255th National Meeting (2018)

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