1D metal nanostructures exhibit unique properties due to their high aspect ratio for use in many applications including electrocatalysis. This work develops a solution‐based approach to 1D multimetal nanostructures with tunable surface structures by combining the two processes of coreduction and galvanic replacement. In this approach, noble metals of Pt and Ru are reduced in the presence of in situ formed Cu seeds. At high concentrations of noble metal precursors, coreduction dominates over galvanic replacement, leading to overgrowth of ultrafine, particulate, or branched structures on the surface of the 1D nanostructures. The surface roughness and composition can be tuned by varying the concentrations of noble metal precursors. The electrochemical reactivity is not only affected by the surface roughness (i.e., the size of particulates and the level of branches) but also the surface composition (i.e., the amount of Pt content). For trimetallic nanostructures, the alloy composition prevents the dissolution of Ru thereby improving electrocatalytic stability of the catalyst under acidic conditions. The structure–property study reveals that the surface structure plays an important role in tailoring the electrocatalytic property of a catalyst.
Asymmetric seed passivation for regioselective overgrowth and formation of plasmonic nanobowls
Plasmonic nanoparticles (NPs) have garnered excitement over the past several decades stemming from their unique optoelectronic properties, leading to their use in various sensing applications and theranostics. Symmetry dictates the properties of many nanomaterials, and nanostructures with low, but still defined symmetries, often display markedly different properties compared to their higher symmetry counterparts. While numerous methods are available to manipulate symmetry, surface protecting groups such as polymers are finding use due to their ability to achieve regioselective modification of NP seeds, which can be removed after overgrowth as shown here. Specifically, poly(styrene- b -polyacrylic acid) (PSPAA) is used to asymmetrically passivate cubic Au seeds through competition with hexadecyltrimethylammonium bromide (CTAB) ligands. The asymmetric passivation via collapsed PSPAA causes only select vertices and faces of the Au cubes to be available for deposition of new material ( i.e. , Au, Au–Ag alloy, and Au–Pd alloy) during seeded overgrowth. At low metal precursor concentrations, deposition follows observations from unpassivated seeds but with new material growing from only the exposed seed portions. At high metal precursor concentrations, nanobowl-like structures form from interaction between the depositing phase and the passivating PSPAA. Through experiment and simulation, the optoelectronic properties of these nanobowls were probed, finding that the interiors and exteriors of the nanobowls can be functionalized selectively as revealed by surface enhanced Raman spectroscopy (SERS).
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- NSF-PAR ID:
- 10393162
- Date Published:
- Journal Name:
- Nanoscale
- Volume:
- 14
- Issue:
- 45
- ISSN:
- 2040-3364
- Page Range / eLocation ID:
- 16918 to 16928
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1039/D2NR05182F
