Formation Pathways of Porous Alloy Nanoparticles through Selective Chemical and Electrochemical Etching

Jiang, Yingying; Wang, Lu; Meunier, Michel; Mirsaidov, Utkur

doi:10.1002/smll.202006953

Cited by 16 publications

(18 citation statements)

References 40 publications

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“…Our recent published work on electrochemical etching of AuAg alloys NPs employed highly specialized in situ TEM for directly observing the nanostructure during the dealloying. [28] In this work, we combined the more accessible optical spectrometer with back-reflection mode microscopy (Figure 8a) to enable real-time monitoring the scattering spectra of individual NPs during the dealloying process. [29] Similar as dealloying colloidal, the spectra of individual NPs also exhibit redshifting and broadening, while significant differences in details are observed among the individual NPs.…”

Section: Single Np In Situ Spectral Characterizationmentioning

confidence: 99%

Porous Au–Ag Nanoparticles from Galvanic Replacement Applied as Single‐Particle SERS Probe for Quantitative Monitoring

Wang

Patskovsky

Gauthier‐Soumis

et al. 2021

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Especially, the porous plasmonic NPs present significant larger tunability in terms of porosity, composition, and larger specific surface area and higher hot spots density compared to the nonporous nanostructures. [3] As their plasmonic peaks can be tuned in the biological transparent window located in NIR region, the porous NPs may be implemented efficiently in biomedical applications, including bioimaging, biodetection, and drug delivery, as well as the surface-enhanced Raman scattering (SERS) based applications. [4] For biosensing and diagnostics, SERS sensing probes are outstanding among various methods. [5] By highly enhancing "finger-print" Raman signal, SERS substrates and probes show promises in analytical chemistry and biochemistry detection with low detection limits. [6] The growing demand for accurate, personalized diagnosis and therapy is opening up new areas of biomedical application with SERS individual nanoprobes, [7] such as, multiplex Raman cellular detection and differentiation, or ultrasensitive multiplex quantitation of microorganisms. [8] In addition, single NPs exhibit great potential in the use of SERS nanoprobes for cyto-and histopathological diagnostics, where they can give an improvement over the existing tissue imaging system using Raman spectroscopy, [9] by providing local enhancement in spatial Raman mapping studies at the cellular and subcellular level. [10] Plasmonic NPs, especially Au-Ag NPs, provides adjustable SERS probes with high enhancement, due to their LSPR behaviors and their designable structures with high hot spots density. The rough surface, assemblies, nanoscale curvature and gap are promising structures for SERS. [11] However, the reproducibility and the stability remain as the main challenge for practical applications. Therefore, it becomes important to have a controllable synthetic strategy for plasmonic NPs with designed nanostructure, clean surface and aqueous dispersibility, to facilitate the wide application in biosensing.Porous and hollow plasmonic structures have been widely explored using the galvanic replacement reaction (GRR) approach, which removes the less noble metal from the template and replaces it with more noble metal via redox process, while forming vacancies in the multimetallic structure. [12] In Plasmonic nanostructures have raised the interest of biomedical applications of surface-enhanced Raman scattering (SERS). To improve the enhancement and produce sensitive SERS probes, porous Au-Ag alloy nanoparticles (NPs) are synthesized by dealloying Au-Ag alloy NP-precursors with Au or Ag core in aqueous colloidal environment through galvanic replacement reaction. The novel designed core-shell Au-Ag alloy NP-precursors facilitate controllable synthesis of porous nanostructure, and dealloying degree during the reaction has significant effect on structural and spectral properties of dealloyed porous NPs. Narrow-dispersed dealloyed NPs are obtained using NPs of Au/Ag ratio from 10/90 to 40/60 with Au and Ag core to produce solid core@porous shell and po...

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Section: Single Np In Situ Spectral Characterizationmentioning

confidence: 99%

Porous Au–Ag Nanoparticles from Galvanic Replacement Applied as Single‐Particle SERS Probe for Quantitative Monitoring

Wang

Patskovsky

Gauthier‐Soumis

et al. 2021

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“…Moreover, the porosity of nanoparticles could also be modulated by the electrochemical potential in the same electrochemical liquid cell. [ 88 ] The more uniform pore sizes are produced in the electrochemical dealloying of AuAg nanoparticles than in chemical etching (Figure 7D). The fewer but larger pores appear at the low voltage etching of +0.5 V. During the dealloying processes of both cases, the Ag dissolution leads to the formation of small pores while the Au diffusion promotes the coalescence of the pores and the Au‐rich passivation layer preserves the porous shell.…”

Section: The Various Studies On Oxidative Etching By In Situ Liquid C...mentioning

confidence: 99%

“…Since then, some researchers have added the third reference electrode, used real electrode materials, and so forth. [87][88] Figure 7A,B shows SiN x liquid cells with heating chips and electrochemical cells with a threeelectrode configuration for tracking different evolutionary pathways of Pt-Ni rhombic dodecahedron. [87] During the chemical etching at 90 °C (Figure 7Ca), localized corrosion occurs at the beginning of the stage.…”

Section: Electrochemical Etchingmentioning

confidence: 99%

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Unveiling the Dynamic Oxidative Etching Mechanisms of Nanostructured Metals/Metallic Oxides in Liquid Media Through In Situ Transmission Electron Microscopy

Zhang

Sun

Kang

et al. 2022

Adv Funct Materials

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Oxidative etching in nanostructured metals and metallic oxides plays a fundamental role in numerous areas of chemical synthesis and materials processing for the semiconductor industry. An in-depth understanding of the oxidative etching mechanisms is of great significance to design various fascinating nanomaterials for practical application. In situ liquid cell transmission electron microscopy (TEM) has the merits of high temporal and spatial resolutions in real-time, and thus it can provide solid evidence directly for the dynamic evaluation of oxidative etching in nanostructured materials that occur in solution. Herein, the recent progress of oxidative etching in nanostructured metals and metallic oxides is overviewed. First, the advancements in liquid cells designs are briefly introduced for in situ TEM observation. Subsequently, in situ liquid cell TEM/STEM advances for the oxide etching mechanisms in different surface chemistry surroundings are systematically described. In addition, both the galvanic replacement and electrochemical etching reactions are also discussed. Finally, the challenges and opportunities in utilizing the in situ liquid cell TEM technique to visualize a specific dynamic oxidative etching process are proposed. This review will provide deep insights into dynamic changes in oxidative etching processes of nanostructured materials and assist in formulating design rules for developing high-end advanced devices.

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“…Other elemental analysis techniques like energy-dispersive X-ray spectroscopy (EDS) combined with scanning transmission electron microscopy (STEM) provide valuable elemental mapping of individual nanoparticles . However, EDS/STEM analyses require dried samples and are limited by the number of nanoparticles within a field of view, which restricts sample size .…”

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confidence: 99%

Quantifying Chemical Composition and Reaction Kinetics of Individual Colloidally Dispersed Nanoparticles

et al. 2021

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To control a nanoparticle's chemical composition and thus function, researchers require readily accessible and economical characterization methods that provide quantitative in situ analysis of individual nanoparticles with high throughput.Here, we established dual analyte single-particle inductively coupled plasma quadrupole mass spectrometry to quantify the chemical composition and reaction kinetics of individual colloidal nanoparticles. We determined the individual bimetallic nanoparticle mass and chemical composition changes during two different chemical reactions: (i) nanoparticle etching and (ii) element deposition on nanoparticles at a rate of 300+ nanoparticles/min. Our results revealed the heterogeneity of chemical reactions at the single nanoparticle level. This proof-of-concept study serves as a framework to quantitatively understand the dynamic changes of physicochemical properties that individual nanoparticles undergo during chemical reactions using a commonly available mass spectrometer. Such methods will broadly empower and inform the synthesis and development of safer, more effective, and more efficient nanotechnologies that use nanoparticles with defined functions.

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Formation Pathways of Porous Alloy Nanoparticles through Selective Chemical and Electrochemical Etching

Cited by 16 publications

References 40 publications

Porous Au–Ag Nanoparticles from Galvanic Replacement Applied as Single‐Particle SERS Probe for Quantitative Monitoring

Porous Au–Ag Nanoparticles from Galvanic Replacement Applied as Single‐Particle SERS Probe for Quantitative Monitoring

Unveiling the Dynamic Oxidative Etching Mechanisms of Nanostructured Metals/Metallic Oxides in Liquid Media Through In Situ Transmission Electron Microscopy

Quantifying Chemical Composition and Reaction Kinetics of Individual Colloidally Dispersed Nanoparticles

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