Structure/processing relationships in the fabrication of nanoporous gold

Kertis, F.; Snyder, Joshua; Govada, Lata; Khurshid, Sarfraz; Chayen, Naomi E.; Erlebacher, Jonah

doi:10.1007/s11837-010-0087-6

Cited by 84 publications

(64 citation statements)

References 39 publications

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“…This may arise from the mediator / enzyme complex inhabiting different environments within the pores, such peak splitting was not observed for laccase and cellobiose dehydrogenase (data not shown). The rate of O 2 reduction catalyzed by MvBOD and mediated by Os(bpy) 2 .PVI in the film was high when compared to the rate of O 2 diffusion in the electrolyte, resulting in depletion of O 2 at the electrode surface. Thus, concentration polarization, a consequence of not rotating the electrode, was manifested as a peak current on the voltammogram.…”

Section: Voltammetric Characterization Of Cyt C Immobilized On Planarmentioning

confidence: 99%

“…The mediator Os(bpy) 2 55 The catalytic current will be limited by the enzyme-catalysed rate of O 2 reduction if too little enzyme is present or by increased resistance in the film if too much non-conductive enzyme is present. 55 At 22.8 wt.…”

Section: Voltammetric Characterization Of Cyt C Immobilized On Planarmentioning

confidence: 99%

“…[1][2][3] np-Au is conductive, chemically and mechanically stable, free of surface contaminants (arising from preparation in nitric or perchloric acid), biocompatible, and easily functionalized. [1][2][3] It has a high surface-to-volume ratio and large surface area with pore sizes that are tunable from the nanometer to micron scale. These properties make np-Au attractive for applications in the immobilization of enzymes or antibodies, 4,5 energy storage, 6 catalysis, 7 and bio/fuel cells.…”

Section: Introductionmentioning

confidence: 99%

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Characterization of Nanoporous Gold Electrodes for Bioelectrochemical Applications

Scanlon¹,

Salaj-Kośla²,

Belochapkine³

et al. 2011

Langmuir

104

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ABSTRACT. The high surface areas of nanostructured electrodes can provide for significantly enhanced surface loadings of electroactive materials. The fabrication and characterisation of nanoporous gold (np-Au) substrates as electrodes for bioelectrochemical applications is described.Robust np-Au electrodes were prepared by sputtering a gold-silver alloy onto a glass support and subsequent de-alloying of the silver component. Alloy layers were prepared with either a uniform or non-uniform distribution of silver and, post de-alloying, showed clear differences in morphology on characterisation with scanning electron microscopy. Redox reactions under kinetic control, in particular measurement of the charge required to strip a gold oxide layer, provided the most accurate measurements of the total electrochemically addressable electrode surface area, A real .Values of A real up to 28 times that of the geometric electrode surface area, A geo , were obtained. For diffusion controlled reactions overlapping diffusion zones between adjacent nanopores established limiting semi-infinite linear diffusion fields where the maximum current density was dependent on A geo . The importance of measuring the surface area available for the immobilisation was determined 2 using the redox protein, cyt c. The area accessible to modification by a biological macromolecule, A macro , such as cyt c was reduced by up to 40 % compared to A real , demonstrating that the confines of some nanopores were inaccessible to large macromolecules due to steric hindrances. Preliminary studies on the preparation of np-Au electrodes modified with osmium redox polymer hydrogels and Myrothecium verrucaria bilirubin oxidase (MvBOD) as a biocathode were performed; current densities of 500 A cm -2 were obtained in unstirred solutions.

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Section: Voltammetric Characterization Of Cyt C Immobilized On Planarmentioning

confidence: 99%

Section: Voltammetric Characterization Of Cyt C Immobilized On Planarmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Characterization of Nanoporous Gold Electrodes for Bioelectrochemical Applications

Scanlon¹,

Salaj-Kośla²,

Belochapkine³

et al. 2011

Langmuir

104

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“…16,17 A disadvantage of this nanoscale morphology in the context of applications is that it is thermodynamically unstable and prone to coarsening. 10,18,19 For example, the length scale of both ligaments and pores of np-Au increases by more than two orders of magnitude by heating the material to 800 o C. 18 Coarsening severely limits the practical applications of np-Au as it leads, for example, to a loss of catalytically active surface and reduces the mechanical strength 20 that is important for the actuator application. Consequently, several strategies have been tested to increase the thermal stability of this material.…”

mentioning

confidence: 99%

ALD Functionalized Nanoporous Gold: Thermal Stability, Mechanical Properties, and Catalytic Activity

et al. 2011

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Nanoporous metals have many technologically promising applications, but their tendency to coarsen limits their long-term stability and excludes high temperature applications. Here, we demonstrate that atomic layer deposition (ALD) can be used to stabilize and functionalize nanoporous metals. Specifically, we studied the effect of nanometer-thick alumina and titania ALD films on thermal stability, mechanical properties, and catalytic activity of nanoporous gold (np-Au). Our results demonstrate that even only 1 nm thick oxide films can stabilize the nanoscale morphology of np-Au up to 1000°C, while simultaneously making the material stronger and stiffer. The catalytic activity of np-Au can be drastically increased by TiO2 ALD coatings. Our results open the door to high-temperature sensor, actuator, and catalysis applications and functionalized electrodes for energy storage and harvesting applications.

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“…8) In principle, as the rate of etching exceeds the rate of diffusion, the strut and pore sizes can be reduced to a few nanometers. 9) Experimentally, however, the actual strut and pore sizes are many orders of magnitude larger than the theoretically expected values. 10) The difference between the theoretical and the actual pore sizes is generally due to the result of an inhomogeneous microstructure in the parent two-component material, because it is extremely difficult to achieve a completely homogeneous two-component parent material.…”

Section: Introductionmentioning

confidence: 84%

Development of Nanoporous Copper Foams by Chemical Dealloying of Mechanically Alloyed Al–Cu Compounds

Nam

Choe

et al. 2014

Mater. Trans.

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We developed open-cell copper foams with uniformly distributed nanopores by chemical dealloying of Al 2 Cu samples that were synthesized by a powder process. High-energy ball-milling was utilized for mechanical alloying of aluminum and copper powders and either hot rolling or hot pressing was then employed to consolidate the ball-milled powders into sheets or pellets. Subsequent dealloying aluminum from the samples produced nanoporous copper foams. X-ray diffractometry and scanning electron microscopy confirmed the uniform formation of Al 2 Cu and aluminum phases prior to dealloying, and the introduction of nanoporous structures after dealloying.

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Structure/processing relationships in the fabrication of nanoporous gold

Cited by 84 publications

References 39 publications

Characterization of Nanoporous Gold Electrodes for Bioelectrochemical Applications

Characterization of Nanoporous Gold Electrodes for Bioelectrochemical Applications

ALD Functionalized Nanoporous Gold: Thermal Stability, Mechanical Properties, and Catalytic Activity

Development of Nanoporous Copper Foams by Chemical Dealloying of Mechanically Alloyed Al–Cu Compounds

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Structure/processing relationships in the fabrication of nanoporous gold

Cited by 84 publications

References 39 publications

Characterization of Nanoporous Gold Electrodes for Bioelectrochemical Applications

Characterization of Nanoporous Gold Electrodes for Bioelectrochemical Applications

ALD Functionalized Nanoporous Gold: Thermal Stability, Mechanical Properties, and Catalytic Activity

Development of Nanoporous Copper Foams by Chemical Dealloying of Mechanically Alloyed Al&ndash;Cu Compounds

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Development of Nanoporous Copper Foams by Chemical Dealloying of Mechanically Alloyed Al–Cu Compounds