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We report the use of gold nanoparticle surface chemistry as a tool for site-selective noble metal deposition onto colloidal gold nanoparticle substrates. Specifically, we demonstrate that partial passivation of the gold nanoparticle surface using thiolated ligands can induce a transition from linear palladium island deposition to growth of palladium selectively at plasmonic hotspots on the edges or vertices of the underlying particle substrate. Further, we demonstrate the broader applicability of this approach with respect to substrate morphology (e.g., prismatic and rod-shaped nanoparticles), secondary metal (e.g., palladium, gold, and platinum), and surface ligand (e.g., surfactant molecules and n-alkanethiols). Taken together, these results demonstrate the important role of metal-ligand surface chemistry and ligand packing density on the resulting modes of multimetallic nanoparticle growth, and in particular, the ability to direct that growth to particle regions of impact such as plasmonic hotspots. [ABSTRACT FROM AUTHOR]

Copper-containing nanomaterials are attractive due to the natural abundance, low cost, and unique catalytic properties of copper metal. Copper may also be used as a representative system to study the formation of mixed metal nanoparticles containing 3d transition metals. These elements pose challenges to traditional metal nanoparticle synthesis strategies due to competing formation of both oxides and hydroxides, depending on metal identity. Here, we analyze copper deposition pathways on gold nanoprism substrates using a combination of electron microscopy and X-ray photoelectron spectroscopy techniques, demonstrating conditions for both core@shell and island growth modes. Elemental analysis by X-ray photoelectron spectroscopy and Auger electron spectroscopy indicate that the final nanoparticle products contain metallic copper. Together, these results elucidate important trends for incorporating 3d transition metals into traditional colloidal syntheses of multimetallic nanostructures. [ABSTRACT FROM AUTHOR]

Seedlessinitiation has been used as a simple and sustainable alternativeto seed-mediated production of two canonical anisotropic gold nanoparticles:nanorods and nanoprisms. The concentration of reducing agent duringthe nucleation event was found to influence the resulting productmorphology, producing nanorods with lengths from 30 to 630 nm andtriangular or hexagonal prisms with vertex-to-vertex lengths rangingfrom 120 to over 700 nm. The seedless approach is then used to eliminateseveral chemical reagents and reactions steps from classic particlepreparations while achieving almost identical nanoparticle productsand product yields. Our results shed light on factors that influence(or do not influence) the evolution of gold nanoparticle shape andpresent a dramatically more efficient route to obtaining these architectures.Specifically, using these methods reduces the total amount of reagentneeded to produce nanorods and nanoprisms by as much as 90 wt % and,to the best of our knowledge, has yielded the first report of spectroscopicallydiscernible, colloidal gold nanoplates synthesized using a seedlessmethodology. [ABSTRACT FROM AUTHOR]