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We report a facile route to the synthesis of Ag@Au–Pt trimetallic nanocubes in which the Ag, Au, and Pt atoms are exposed at the corners, side faces, and edges, respectively. Our success relies on the use of Ag@Au nanocubes, with Ag 2 O patches at the corners and Au on the side faces and edges, as seeds for the site-selective deposition of Pt on the edges only in a reaction system containing ascorbic acid (H 2 Asc) and poly(vinylpyrrolidone). At an initial pH of 3.2, H 2 Asc can dissolve the Ag 2 O patches, exposing the Ag atoms at the corners of a nanocube. Upon the injection of the H 2 PtCl 6 precursor, the Pt atoms derived from the reduction by both H 2 Asc and Ag are preferentially deposited on the edges, leading to the formation of Ag@Au–Pt trimetallic nanocubes. We demonstrate the use of 2,6-dimethylphenyl isocyanide as a molecular probe to confirm and monitor the deposition of Pt atoms on the edges of nanocubes through surface-enhanced Raman scattering (SERS). We further explore the use of these bifunctional trimetallic nanoparticles with integrated plasmonic and catalytic properties for in situ SERS monitoring the reduction of 4-nitrothiophenol by NaBH 4 . Upon the removal of Ag via H 2 O 2 etching, the Ag@Au–Pt nanocubes evolve into trimetallic nanoboxes with a wall thickness of about 2 nm and well-defined openings at the corners. The trimetallic nanoboxes embrace plasmon resonance peaks in the near-infrared region with potential in biomedical applications.
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Multilayer electrodeposition of Pt onto 1–2 nm Au nanoparticles using a hydride-termination approach
Here we report on hydride-terminated (HT) electrodeposition of Pt multilayers onto ∼1.6 nm Au nanoparticles (NPs). The results build on our earlier findings regarding electrodeposition of a single monolayer of Pt onto Au NPs and reports relating to HT Pt electrodeposition onto bulk Au. In the latter case, it was found that electrodeposition of Pt from a solution containing PtCl 4 2− can be limited to a single monolayer of Pt atoms if it is immediately followed by adsorption of a monolayer of H atoms. The H-atom capping layer prevents deposition of Pt multilayers. In the present report we are interested in comparing the structure of NPs after multiple HT Pt electrodeposition cycles to the bulk analog. The results indicate that a greater number of HT Pt cycles are required to electrodeposit both a single Pt monolayer and Pt multilayers onto these Au NPs compared to bulk Au. Additionally, detailed structural analysis shows that there are fundamental differences in the structures of the AuPt materials depending on whether they are prepared on Au NPs or bulk Au. The resulting structures have a profound impact on formic acid oxidation electrocatalysis.
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- Award ID(s):
- 1855980
- PAR ID:
- 10178834
- Date Published:
- Journal Name:
- Nanoscale
- Volume:
- 12
- Issue:
- 20
- ISSN:
- 2040-3364
- Page Range / eLocation ID:
- 11026 to 11039
- 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/d0nr02929g
