| Autor: |
Leary RK; Department of Materials Science and Metallurgy, University of Cambridge , 27 Charles Babbage Road, Cambridge CB3 0FS, U.K., Kumar A; Department of Chemistry, Rice University , 6100 Main Street, Houston, Texas 77005, United States., Straney PJ; Department of Chemistry, University of Pittsburgh , 219 Parkman Avenue, Pittsburgh, Pennsylvania 15260, United States., Collins SM; Department of Materials Science and Metallurgy, University of Cambridge , 27 Charles Babbage Road, Cambridge CB3 0FS, U.K., Yazdi S; Department of Materials Science and Nanoengineering, Rice University , 6100 Main Street, Houston, Texas 77005, United States., Dunin-Borkowski RE; Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons (ER-C) and Peter Grünberg Institute (PGI-5), Forschungszentrum Jülich GmbH, D-52425 Jülich, Germany., Midgley PA; Department of Materials Science and Metallurgy, University of Cambridge , 27 Charles Babbage Road, Cambridge CB3 0FS, U.K., Millstone JE; Department of Chemistry, University of Pittsburgh , 219 Parkman Avenue, Pittsburgh, Pennsylvania 15260, United States., Ringe E; Department of Chemistry, Rice University, 6100 Main Street, Houston, Texas 77005, United States; Department of Materials Science and Nanoengineering, Rice University, 6100 Main Street, Houston, Texas 77005, United States. |
| Abstrakt: |
Catalytic and optical properties can be coupled by combining different metals into nanoscale architectures in which both the shape and the composition provide fine-tuning of functionality. Here, discrete, small Pt nanoparticles (diameter = 3-6 nm) were grown in linear arrays on Au nanoprisms, and the resulting structures are shown to retain strong localized surface plasmon resonances. Multidimensional electron microscopy and spectroscopy techniques (energy-dispersive X-ray spectroscopy, electron tomography, and electron energy-loss spectroscopy) were used to unravel their local composition, three-dimensional morphology, growth patterns, and optical properties. The composition and tomographic analyses disclose otherwise ambiguous details of the Pt-decorated Au nanoprisms, revealing that both pseudospherical protrusions and dendritic Pt nanoparticles grow on all faces of the nanoprisms (the faceted or occasionally twisted morphologies of which are also revealed), and shed light on the alignment of the Pt nanoparticles. The electron energy-loss spectroscopy investigations show that the Au nanoprisms support multiple localized surface plasmon resonances despite the presence of pendant Pt nanoparticles. The plasmonic fields at the surface of the nanoprisms indeed extend into the Pt nanoparticles, opening possibilities for combined optical and catalytic applications. These insights pave the way toward comprehensive nanoengineering of multifunctional bimetallic nanostructures, with potential applications in plasmon-enhanced catalysis and in situ monitoring of chemical processes via surface-enhanced spectroscopy. |
