Decoupling Mechanisms of Platinum Deposition on Colloidal Gold Nanoparticle Substrates

• Published in: Journal of the American Chemical Society Vol. 136; no. 22; pp. 7873 - 7876
• Main Authors: Straney, Patrick J, Marbella, Lauren E, Andolina, Christopher M, Nuhfer, Noel T, Millstone, Jill E
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 04.06.2014
• ISSN: 0002-7863; 1520-5126
• DOI: 10.1021/ja504294p

Nanoscale platinum materials are essential components in many technologies, including catalytic converters and fuel cells. Combining Pt with other metals can enhance its performance and/or decrease the cost of the technology, and a wide range of strategies have been developed to capitalize on these advantages. However, wet chemical synthesis of Pt-containing nanoparticles (NPs) is challenging due to the diverse metal segregation and metal–metal redox processes possible under closely related experimental conditions. Here, we elucidate the relationship between Pt­(IV) speciation and the formation of well-known NP motifs, including frame-like and core–shell morphologies, in Au–Pt systems. We leverage insights gained from these studies to induce a controlled transition from redox- to surface chemistry-mediated growth pathways, resulting in the formation of Pt NPs in epitaxial contact and linear alignment along a gold nanoprism substrate. Mechanistic investigations using a combination of electron microscopy and 195Pt NMR spectroscopy identify Pt­(IV) speciation as a crucial parameter for understanding and controlling the formation of Pt-containing NPs. Combined, these findings point toward fully bottom-up methods for deposition and organization of NPs on colloidal plasmonic substrates.