High-temperature stability of Au/Pd/Cu and Au/Pd(P)/Cu surface finishes

Ho, Cheng–En; Hsieh, W.Z.; Lee, P.T.; Huang, Yufang; Kuo, T.T.

doi:10.1016/j.apsusc.2017.11.247

Cited by 16 publications

(4 citation statements)

References 27 publications

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“…The morphology transformation is further revealed by investigating synthetic parameters. According to the Kirkendall effect, the pore morphology in porous–spiny Au–Ag NPs can be generated due to the unbalanced diffusion rate of Au and Ag elements in the replacement reaction between Ag NPs and HAuCl 4 . , To verify the above inference, the replacement reaction between Ag NPs and HAuCl 4 is performed without the addition of AA and PVP. As described in the TEM image (Figure S2), the as-obtained products still have obvious pore morphology.…”

Section: Resultsmentioning

confidence: 97%

“…Recently, by means of element diffusion, Au–Cu and Ag–Pt NPs with both corner/edge and void can be synthesized using common spherical NPs as intermediates. , On this basis, it can be inferred that the preparation method determined by the element diffusion can be extended to obtain Au–Ag NPs with special morphology. Therefore, on the basis of the element diffusion, we tried to controllably and facilely prepare Au–Ag NPs with special morphology using common spherical Ag NPs as intermediates.…”

Section: Introductionmentioning

confidence: 99%

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Au–Ag Nanoparticles with Controllable Morphologies for the Surface-Enhanced Raman Scattering Detection of Trace Thiram

Sun

Cao

Yuan

et al. 2023

ACS Appl. Nano Mater.

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Surface-enhanced Raman scattering (SERS) technique has been limitedly applied to the detection of trace thiram due to the weak activity of employed substrates. In this work, Au–Ag nanoparticles (NPs) with controllable morphologies are synthesized and used as SERS-active substrates for the detection of trace thiram. Porous–spiny Au–Ag NPs are synthesized with spherical Ag NPs as intermediates through in situ redox. Annular Au–Ag NPs can be further obtained by heating porous–spiny Au–Ag NPs. Here, the morphology transformation of Au–Ag NPs is first completed by means of the element diffusion theory, providing a strategy for the morphology control of complex Au–Ag NPs. Additionally, these Au–Ag NPs with optimized morphologies were chosen as substrates for the successful SERS detection of trace thiram. Especially, porous–spiny Au–Ag NPs show superior sensitivity and reproducibility. Meanwhile, using porous–spiny Au–Ag NPs as SERS-active substrates, thiram can be quantitatively detected in the range from 10–3 to 10–11 M. Thus, it is inferred that Au–Ag NPs with optimized morphologies will have great potential in the field of trace analyte detection related to food safety and environmental protection.

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Section: Resultsmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

Au–Ag Nanoparticles with Controllable Morphologies for the Surface-Enhanced Raman Scattering Detection of Trace Thiram

Sun

Cao

Yuan

et al. 2023

ACS Appl. Nano Mater.

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“…Ultrathin metal films or nanostructures supported on a metallic substrate have attracted increasing interest, owing to their fundamental significance and potential applications in electrocatalysis, 1,2 heterogeneous catalysis, 3 and microelectronics. 4 For electrocatalysis, supported metal thin layers 5 have become a critical model system to understand the effects of lattice strains and crystallographic orientations in tuning the adsorption energies and reactivities of surface molecules and intermediates. Particularly, Cu overlayers of varying thickness supported on precious metal single crystals, such as Pt(111) and Au(111), 6−8 have been used to understand and tune the reactivity and product selectivity of the CO 2 reduction reaction.…”

Section: ■ Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Origin of the Thickness-Dependent Oxidation of Ultrathin Cu Films on Au(111)

et al. 2018

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Ultrathin Cu films deposited on a metal substrate have been used as a model system to understand the structure−function relationship in electrocatalysis, heterogeneous catalysis, and microelectronics. The stability of ultrathin Cu films against oxidation has been of particular interest, but there is a lack of microscopic understanding. We report here an atomic-level study on the thicknessdependent oxidation kinetics of Cu layers on Au(111), from ultrahigh vacuum to near ambient conditions. Ultrathin Cu films on Au(111) were found to exhibit a superior oxidation resistance over Cu(111), and their oxidation resistances increase in the order of Cu(111) < 2.4 ML Cu < 0.4 ML Cu. For 0.4 ML Cu, the spontaneous subsurface diffusion of Cu at 300 K and the formation of a Au-rich surface alloy inhibit the formation of copper oxides at the O 2 pressure below 10 −4 mbar. However, at near ambient conditions, 0.4 ML Cu would be partially oxidized to the CuO phase directly. In contrast, multilayer Cu or bulk Cu(111), though oxidized more rapidly, forms only Cu 2 O surface layers under the same oxidation conditions. We analyzed further the atomic process of alloying at elevated temperatures. An intermediate Au 3 Cu alloy phase was suggested at the subsurface at 400 K. The diffusion of Cu into bulk Au(111) at 600 K prevents the formation of copper oxides at 300 K even under near-ambient conditions. Our study could thus provide insight for the rational design of a highly efficient Cu-based oxidation catalyst.

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