Potentiostatic studies of electrochemical nucleation

Gunawardena, Gamini; Hills, G. J.; Montenegro, Irene

doi:10.1016/0013-4686(78)80026-7

Cited by 111 publications

(52 citation statements)

References 15 publications

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“…Deposition of mercury was found to follow the behavior expected for the spherical growth of a mercury nucleus [42][43], i.e., the mercury radius is linearly proportional to ?jz (Figure 8) according to 2MDCt ' I 2 r = ( 7 ) where A4 is the atomic weight of mercury, D the diffusion coefficient of Hg" (1.06 x lo-' cm2/s), C the concentration of Hg", p the density of mercury, and t the deposition time.…”

Section: Reproducibility Of Mercury Layer Preparationmentioning

confidence: 90%

Reproducible, reliable and rugged Hg‐plated Ir‐based microelectrode for in situ measurements in natural waters

1995

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Construction of a reproducible, reliable and rugged iridium-based microelectrode is described. Perfect electrical contact, Ir-glass sealing and Ir disk morphology are the key points for obtaining reproducible voltammetric sensors. These points are discussed in detail and optimal fabrication conditions are given. Electron bombardment under vacuum yielded good soldering between Ir and Cu electrical cable. Reproducible polishing of the microelectrode to a mirror like Ir disk surface is obtained with silicon carbide pads and diamond paste using an automatic home made polisher. Cyclic voltammetry and optical microscopy have been used to characterize this microelectrode. Hgplated Ir-based microelectrodes are prepared by electrodeposition of mercury on the iridium disk substrate. Reproducibility and reliability close to 100% have been obtained for Ir-based microelectrode preparation, mercury layer deposition and trace metal measurements by differential pulse anodic stripping voltammetry (DPASV) and square wave anodic stripping voltammetry (SWASV) in synthetic solutions even at low ionic strength M). Continuous measurements over long periods of time indicate that the Hg-plated Ir-based microelectrodes can be used for several days without renewal of the mercury layer. These microelectrodes were applied to lead and cadmium speciation studies directly in river waters by SWASV without any separation. The results show that free Pb" and Cd" concentrations as low as 0.5nM and O . l n~ respectively can be determined by direct measurements, without perturbing the medium. The lifetime of these microelectrodes in the present state of the art is more than 2 years.

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Section: Reproducibility Of Mercury Layer Preparationmentioning

confidence: 90%

Reproducible, reliable and rugged Hg‐plated Ir‐based microelectrode for in situ measurements in natural waters

1995

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“…[5][6][7] The studies of nucleation via electrochemical means have been carried out as those have the ability to control the degree of supersaturation. 8) The studies of the potentiostatic current transient of the electrochemical nucleation and growth have been carried out by Gunawardena, Scharifker, Astley, and Hills et al [8][9][10][11][12][13][14] Valderrama et al 15) studied the electrodeposition of indium thin films on Mo/Cu substrates using chronoamperometry. They applied their results to the electrocrystallization theories developed by Scharifker et al [8][9][10] and observed that the nucleation of indium on Mo/Cu was adjusted to a three-dimensional growth under instantaneous nucleation limited by diffusion.…”

Section: 4)mentioning

confidence: 99%

Nucleation Process of Indium on a Copper Electrode

Chung¹,

Lee²

2013

Journal of Electrochemical Science and Technology

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:The electrodeposition of indium onto a copper electrode from an aqueous sulfate solution containing In 3+ was studied by means of cyclic voltammetry and chronoamperometry. Reduction and oxidation of indium on copper were investigated by using cyclic voltammograms at different negative limiting potentials and at different scan rates in cumulative cycles. Cyclic voltammograms indicated that reduction and oxidation processes of indium could involve various reactions. Chronoamperometry was carried out to analyze the nucleation mechanism of indium in the early stage of indium electrodeposition. The non-dimensional plot of the current transients at different potentials showed that the shape of the plot depended on the applied potential. The nucleation of indium at potential step of −0.6~−0.8 V was close to progressive nucleation limited by diffusion. However the nondimensional plot of current transients for the indium nucleation showed different behaviors from theoretical curves at the potential step lower than −0.8 V.

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“…This is revealed from an extended region into solution for a high population of electroactive species to diffuse down to the electrode surface by linear diffusion [44].…”

Section: Theoretical Considerations Of Spherical Diffusion At a Nanodmentioning

confidence: 99%

“…Thus, the analytical expression for diffusion to the effective surface area of a random distribution of recessed nanodes, which are established during ion track etching processing of the membrane, is complicated. However, solutions are available by assuming the fact that the same amount of material is entering through the boundary of the diffusion zones by linear diffusion as that from the radial spherical diffusion to the nanodes [44][45][46].…”

Section: Theoretical Considerations Of Spherical Diffusion At a Nanodmentioning

confidence: 99%

Template Synthesis of Magnetic Nanowire Arrays

Valizadeh

Strömberg

Strömme

2008

Nanostructured Materials in Electrochemistry

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IntroductionDuring the late 20th century, the growing interest in creating advanced materials using nanoscaled building blocks was employed to develop synthetic techniques for re-engineering existing materials to novel functional materials such as quantum dots, nanodots, nanorods, nanotubes, nanofibrils and quantum wires. These nanowires can act as one-dimensional conductors with interesting electronic and optical properties. Moreover, nanowires may find applications in ultrasensitive chemical and biological sensors.To date, a physical vapor deposition (PVD) technique followed by lithography is usually considered to represent the ultimate method for producing nanoscaled materials. Although a number of successful efforts have been reported on the fabrication of freestanding nanopillars or nanowells using lithographic techniques, there is a whole range of potential obstacles for these approaches. These arise mainly from the fact that, when the technologies are pushed to smaller sizes, the cost rapidly escalate and the tolerances are more difficult to maintain. The lithographic processes used to pattern nanoelectronic structures also currently limit the dimensions of the electronic components such as nanowires. Optical lithography is limited by the wavelength of the light used to produce the wires. Consequently, the wavelength of light used is moving into the deeper regions of the ultraviolet (UV) spectrum, and the cost of fabricating optical components to achieve this is expected to rise at an astronomic rate. These challenges have forced many to seek new nanofabrication techniques, especially those which grow nanostructures directly in the openings of a template. One of the most successful approaches to these nanofabrication methods is known as the membrane-based synthesis of nanomaterials [1][2][3][4], where the membrane acts as a template for the electrodeposition of multilayered nanowires, as well as for single metallic nanowires [5,6]. The advantage of using template synthesis of nanowires is that it can be considered as an alternative solution to overcome the difficulty in fabricating fibrils with very small diameters by lithographic methods [7].

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Potentiostatic studies of electrochemical nucleation

Cited by 111 publications

References 15 publications

Reproducible, reliable and rugged Hg‐plated Ir‐based microelectrode for in situ measurements in natural waters

Reproducible, reliable and rugged Hg‐plated Ir‐based microelectrode for in situ measurements in natural waters

Nucleation Process of Indium on a Copper Electrode

Template Synthesis of Magnetic Nanowire Arrays

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