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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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Rational design and synthesis of bifunctional metal nanocrystals for probing catalytic reactions by surface-enhanced Raman scattering
This report highlights recent progress in the rational design, synthesis, and applications of bimetallic nanocrystals with integrated SERS and catalytic activities. The ultimate goal is to develop bifunctional nanocrystals as a SERS probe for monitoring a catalytic reaction in situ . We first introduce seeded growth as a facile and powerful route to the syntheses of bifunctional nanocrystals with catalytic activities arising from Au or Pd, in addition to plasmonic properties originating from Ag or Au. Specifically, we discuss two distinctive pathways, namely conformal and site-selected deposition of a second metal on the surface of a noble-metal nanocrystal seed, for the fabrication of bifunctional nanocrystals with controlled composition and morphology. We then discuss the application of these bifunctional nanocrystals as unique probes for in situ SERS monitoring of the Au or Pd-catalyzed reduction of 4-nitrothiophenol to 4-aminothiophenol by NaBH 4 and the Ag-catalyzed oxidation of 4-aminothiophenol to trans -4,4′-dimercaptoazobenzene by the O 2 from air. We conclude this review with perspectives on the future development.
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- Award ID(s):
- 1708300
- PAR ID:
- 10063805
- Date Published:
- Journal Name:
- Journal of Materials Chemistry C
- Volume:
- 6
- Issue:
- 20
- ISSN:
- 2050-7526
- Page Range / eLocation ID:
- 5353 to 5362
- 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/c8tc01394b
