Chemically controlled interfacial nanoparticle assembly into nanoporous gold films for electrochemical applications

Christiansen, Mikkel Undall-Behrend; Šešelj, Nedjeljko; Engelbrekt, Christian; Wagner, Markus Robert; Stappen, Frederick N.; Zhang, Jingdong

doi:10.1039/c7ta08562a

Cited by 13 publications

(10 citation statements)

References 56 publications

(59 reference statements)

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“…The observed hierarchical structure of the AuNP film has been widely reported in a seed-mediated self-assembly synthesis of nanostructured gold thin films. 25,30,40 The formation mechanism of the self-assembled hierarchical structure is typically explained by diffusion limited aggregation (DLA) 30,41,42 in which particles adhere once they collide to each other. In our case, the mechanism of the AuNP film synthesis can also be explained based on the DLA process as follows: AuNPs formed from the auric ions in solution by cryoplasma irradiation were agglomerated to form the hierarchically assembled structures accompanied by the DLA model, and the agglomerated AuNPs were interconnected to each other owing to the further reduction of auric ions by the cryoplasma.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…It is noteworthy that the synthesis of the AuNP film by PFT was performed without any surfactants or additional templates; only cryoplasma jet was irradiated onto the frozen solution using the ice body of the frozen solution as a substrate for the synthesis of the AuNP film in the thin liquid layer. For the chemical synthesis of nanostructured gold such as nanoporous gold, many techniques have been reported previously, such as dealloying, , templating, seed-mediated self-assembly, ,, etc. These chemical methods are potentially susceptible to the effects of impurities, because surfactants or templates are required for the fabrication of nanostructures.…”

Section: Resultsmentioning

confidence: 99%

“…In this study, we demonstrate a thermodynamically size-tunable template and material design at the plasma–ice interface by PFT, using the synthesis of self-standing AuNP films with porous structure as an example (Figure ). Nanostructured gold materials, such as nanoporous gold are promising in the recently developing trend of sustainable development and energy management in harmony with the environment for catalysts, − biosensors, , electrodes for batteries and capacitors, , and stretchable transparent conductors, owing to their desirable features of both gold bulk and size-enhanced effect in the nanoscale. Using PFT, the surfactant-free and area-selective synthesis of self-standing AuNP films with a nano- or microporous structure was accomplished, which was unique in comparison with the conventional chemical synthesis of nanostructured gold materials.…”

Section: Introductionmentioning

confidence: 99%

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Plasma–Ice Interface as Thermodynamically Size-Tunable Reaction Field: Development of Plasma-Assisted Freeze Templating

2019

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Interfaces or interfacial layers, such as gas–liquid interfaces, are critical for many physical and chemical reactions and are utilized for designing a wide range of materials. In this study, we propose a plasma-assisted freeze templating (PFT) method for materials processing. It uses a new type of interfacial reaction field, i.e., plasma–ice interface. In PFT, a micro- or nanoscale liquid layer formed on the ice body of a frozen aqueous solution is used as a reaction field in which the solutes are highly enriched and the chemical reactions are initiated by reactive species from the plasma. We demonstrated the synthesis of a self-standing gold nanoparticle (AuNP) film of porous structure by PFT in which a helium cryoplasma jet was irradiated onto a frozen solution of auric ions. This PFT method accomplished a surfactant-free and area-selective synthesis of a AuNP film and was unique in comparison with the conventional chemical synthesis of nanostructured gold materials. Furthermore, simple control of the AuNP film was demonstrated by tuning the thickness of the thin liquid layer. This was done by changing the temperature or concentration of the aqueous solution. PFT was demonstrated as a thermodynamically size-tunable scheme for material design; it exploits the plasma–ice interface and is expected to become a novel technique for a wide range of micro- and nanoengineering applications.

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Section: ■ Results and Discussionmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Plasma–Ice Interface as Thermodynamically Size-Tunable Reaction Field: Development of Plasma-Assisted Freeze Templating

2019

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“…[2][3][4] These factors can be greatly enhanced by using nanoporous metals characterized by tunable porosity and high structural stability. 18,19 Another class of materials, GNP-containing gels, possess similar properties and are cheaper to fabricate. [20][21][22][23][24][25][26][27] One of the ways to form a GNP-containing gel is to crosslink GNPs decorated by suitable ligands.…”

Section: Introductionmentioning

confidence: 99%

Gelation of patchy ligand shell nanoparticles decorated by liquid-crystalline ligands: computer simulation study

2018

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We consider the coarse-grained modelling of patchy ligand shell nanoparticles with liquid crystalline ligands. The cases of two, three, four and six symmetrically arranged patches of ligands are discussed, as well as the cases of their equatorial and icosahedral arrangement. A solution of decorated nanoparticles is considered within a slit-like pore with solid walls and the interior filled by a polar solvent. The ligands form physical cross-links between the nanoparticles due to strong liquid crystalline interaction, turning the solution into a gel-like structure. Gelation is carried out repeatedly starting each time from a freshly equilibrated dispersed state of nanoparticles. The gelation dynamics and the range of network characteristics of the gel are examined, depending on the type of patchy decoration and on the solution density. Emphasis is given to the theoretical prediction of the type of decoration and the solution density most suitable for producing a uniformly cross-linked and highly elastic gel structure.

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“…In recent years, gold (Au) sponges have attracted great interests due to their high surface area, electrochemical and plasmonic properties, which make them excellent candidates for potential applications, such as catalysts, − fuel cells, , sensors, − and optical devices. , Various methods have been successfully developed for the synthesis of Au sponges, using dealloying of Au–Ag or Au–Cu alloys, self-assembly of Au nanoparticles (Au NPs), − and template-mediated electrochemical deposition. , However, the practical applications of Au sponges have been dampened by their structural instability at high temperature or catalytic reaction conditions, which results in the loss of their unique physical properties. − …”

Section: Introductionmentioning

confidence: 99%

Porous Silica-Coated Gold Sponges with High Thermal and Catalytic Stability

Lee

Kang

Dey

et al. 2018

ACS Appl. Mater. Interfaces

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A method to fabricate porous silica-coated Au sponges that show high thermal and catalytic stability has been developed for the first time. The method involves dense surface functionalization of Au sponges (made by self-assembly of Au nanoparticles) with thiolated poly(ethylene glycol) (SH-PEG), which provides binding and condensation sites for silica precursors. The silica coating thickness can be controlled by using SH-PEG of different molecular weights. The silica-coated Au sponge prepared by using 5 kDa SH-PEG maintains its morphology at temperature as high as 700 °C. The calcination removes all organic molecules, resulting in porous silica-coated Au sponges, which contain hierarchically connected micro- and mesopores. The hierarchical pore structures provide an efficient pathway for reactant molecules to access the surface of Au sponges. The porous silica-coated Au sponges show an excellent catalytic recyclability, maintaining the catalytic conversion percentage of 4-nitrophenol by NaBH to 4-aminophenol as high as 93% even after 10 catalytic cycles. The method may be applicable for other porous metals, which are of great interests for catalyst, fuel cell, and sensor applications.

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Chemically controlled interfacial nanoparticle assembly into nanoporous gold films for electrochemical applications

Abstract: Nanoporous gold (NPG) is an effective material for electrocatalysis and can be made by self-assembly of gold nanoparticles at liquid–air interface.

Cited by 13 publications

References 56 publications

Plasma–Ice Interface as Thermodynamically Size-Tunable Reaction Field: Development of Plasma-Assisted Freeze Templating

Plasma–Ice Interface as Thermodynamically Size-Tunable Reaction Field: Development of Plasma-Assisted Freeze Templating

Gelation of patchy ligand shell nanoparticles decorated by liquid-crystalline ligands: computer simulation study

Porous Silica-Coated Gold Sponges with High Thermal and Catalytic Stability

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