Morphology evolution of Ag/Au nanocomposites via temperature-controlled galvanic exchange to enhance catalytic activity

Park, Tae-Hyeon; Lee, Hyeri; Lee, Jaewon; Jang, Du‐Jeon

doi:10.1039/c6ra26249j

Cited by 14 publications

(6 citation statements)

References 41 publications

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“…Over the last few years, the poising tolerance and the activities of the Pt-based catalyst were improved by introducing various shapes of nanostructures including nanowires 15,16 , nanoparticles 17 , mesoporous 18 , nanospheres 19,20 , and nanotubes 21,22 . Hollow metallic nanoarchitectures are an interesting class of materials due to their unique physical and chemical properties 23 . Hollow nanostructures are considered an extraordinary morphology due to their ‘nanoreactor confinement effect’.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of Hollow Pt-Ni Nanoboxes for Highly Efficient Methanol Oxidation

Jamil

Sohail

Baig

et al. 2019

Sci Rep

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In direct methanol fuel cell technology, highly stable electrochemical catalysts are critically important for their practical utilization at the commercial scale. In this study, sub ~10 nm hollow Pt-Ni (1:1 at. ratio) nanoboxes supported on functionalized Vulcan carbon (Pt-Ni/C-R2) were synthesized through a facile method for the efficient electrooxidation of methanol. Two reaction procedures, namely, a simultaneous reduction and a modified sequential reduction method using a reverse microemulsion (RME) method, were adopted to synthesize solid Pt-Ni NPs and hollow nanoboxes, respectively. To correlate the alloy composition and surface structure with the enhanced catalytic activity, the results were compared with the nanocatalyst synthesized using a conventional NaBH4 reduction method. The calculated electroactive surface area for the Pt-Ni/C-R2 nanoboxes was 190.8 m2.g−1, which is significantly higher compared to that of the Pt-Ni nanocatalyst (96.4 m2.g−1) synthesized by a conventional reduction method. Hollow nanoboxes showed 34% and 44% increases in mass activity and rate of methanol oxidation reaction, respectively, compared to solid NPs. These results support the nanoreactor confinement effect of the hollow nanoboxes. The experimental results were supported by Density Functional Theory (DFT) studies, which revealed that the lowest CO poisoning of the Pt1Ni1 catalyst among all Ptm-Nin mixing ratios may account for the enhanced methanol oxidation. The synthesized hollow Pt-Ni/C (R2) nanoboxes may prove to be a valuable and highly efficient catalysts for the electrochemical oxidation of methanol due to their low cost, numerous catalytically active sites, low carbon monoxide poisoning, large electroactive surface area and long-term stability.

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Section: Introductionmentioning

confidence: 99%

Synthesis of Hollow Pt-Ni Nanoboxes for Highly Efficient Methanol Oxidation

Jamil

Sohail

Baig

et al. 2019

Sci Rep

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“…Bimetallic nanoparticles (Ag–Au and Au–Cu) with porous nanostructure and larger cavities have shown better catalytic performance than those with solid morphology in the literature reports. 48–50 Based on the morphological characterization of treated Au–Ag@HNT, we noticed that porous Au–Ag@HNT became solid Au–Ag@HNT after heating at 200 °C. On comparing the peroxidase-like catalytic efficiency, we found that solid Au–Ag@HNT (200 °C) maintained the same catalytic efficiency as porous Au–Ag@HNT, although solid Au–Ag@HNT (400 °C) showed lower catalytic efficiency ( Fig.…”

Section: Resultsmentioning

confidence: 90%

Au–Ag and Pt–Ag bimetallic nanoparticles@halloysite nanotubes: morphological modulation, improvement of thermal stability and catalytic performance

Tang

Wang

et al. 2018

RSC Adv.

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“…Gold nanoshells represent a spherical layer of gold around a filled or hollow core that can either be solid or porous, [22,23] with the latter possessing notable catalytic [24] and surface-enhanced Raman scattering (SERS) activity. [25,26] To better probe the features of a BAuNS and its external gold layer, we extended the morphological characterization by close-up inspection of its edges via TEM.…”

Section: Introductionmentioning

confidence: 99%

Templated Out‐of‐Equilibrium Self‐Assembly of Branched Au Nanoshells

Marchetti

Gori

Ferretti

et al. 2023

Small

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Grzybowski's research group pioneered the topic, by combining gold NPs (AuNPs) bearing acidic head groups with a pH oscillator that controlled the dissociation of the acidic moieties and the subsequent assembly/disassembly of the AuNPs. [12] To date, light has been the most popular stimulus (fuel) to control NP-based out-ofequilibrium systems, usually leveraging the photoisomerization of azobenzene or spiropyran-functionalized NPs. [13][14][15] Clustering of AuNPs and iron oxide NPs has also been regulated by a chemical reaction cycle that hydrolyzes a carbodiimidebased fuel. [16] A different route to mediate AuNPs self-assembly far from equilibrium was reported by the Klajn's group, who exploited the high local concentration of a surfactant, released near the NP surfaces during their growth, to induce transient assembly of the NPs. [17] Overall, when driving metal NPs selfassembly far from thermodynamic equilibrium, it remains highly challenging to achieve the formation of transient assemblies with a finely tuned and finite morphology. This key feature could ease the actual application of these systems and expand their practical relevance in the design of optoelectronic nanodevices, such as optical switches or waveguides, sensors, and switchable catalysts. [18] To address this challenge, here we employed a spherical peptide-Au superstructure as a template to control the outof-equilibrium self-assembly of AuNPs, realizing a branched Au-nanoshell (BAuNS). Owing to its high stability and positive charge, the chosen template attracts AuCl 4 − ions on its surface and, upon Au reduction to the metallic state, a shell composed of interconnected 5 nm AuNPs is formed over its surface. BAuNS is stabilized by sodium dodecyl sulfate (SDS) that reaches a high localized concentration within the branched AuNPs layer. As SDS concentration gradient equilibrates over time in solution, dismantling of BAuNSs occurs by AuNPs disassembly. Notably, BAuNSs assembly and disassembly favored temporary interparticle plasmonic coupling, leading to a tunable change of the AuNPs optical properties.

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Morphology evolution of Ag/Au nanocomposites via temperature-controlled galvanic exchange to enhance catalytic activity

Abstract: Morphology-controlled Ag/Au nanocomposites have been fabricated facilely via a modified galvanic replacement reaction using Ag nanocubes as sacrificial templates.

Cited by 14 publications

References 41 publications

Synthesis of Hollow Pt-Ni Nanoboxes for Highly Efficient Methanol Oxidation

Synthesis of Hollow Pt-Ni Nanoboxes for Highly Efficient Methanol Oxidation

Au–Ag and Pt–Ag bimetallic nanoparticles@halloysite nanotubes: morphological modulation, improvement of thermal stability and catalytic performance

Templated Out‐of‐Equilibrium Self‐Assembly of Branched Au Nanoshells

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