Imaging the incipient electrochemical oxidation of highly oriented pyrolytic graphite

Goss, Charles A.; Brumfield, Jay C.; Irene, E. A.; Murray, Royce W.

doi:10.1021/ac00058a014

Cited by 135 publications

(147 citation statements)

References 21 publications

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“…For a detailed study of such blisters see [26]. The blisters are soft and seem to be filled with gas [26][27][28]. Applying a force of about 5-10 nN with the tip will flatten the blister.…”

Section: Experiments and Resultsmentioning

confidence: 99%

Influence of the topography on adhesion measured by SFM

Stifter¹,

Weilandt²,

Marti³

et al. 1998

Applied Physics A: Materials Science & Processing

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Surface properties such as adhesion are influenced by the surface topography. This dependency complicates any quantitative investigation of the material constants. A simple and efficient model is used to calculate the influence of the topography on the pull of force determined by a scanning force microscope (SFM). In the model the SFM tip is represented by a sphere. The sample surface is modeled by two geometries: a step on a plane and a blister (spherical cap) on a plane. The atomic interaction between the tip and the surface is of the Lennard-Jones type. The theoretical results are compared with SFM-measurements on highly oriented pyrolytic graphite (HOPG) in electrolytic environment. The calculations are in good agreement with the measured images.The SFM has become an indispensable tool for surface investigations on the nanometer scale. With the SFM it is possible to image the sample topography and properties such as friction [1-3], local stiffness [4], the adhesive force [5-8], and magnetic [9] and electrical forces [9]. In order to investigate these properties, specialized measurement modes are used. One main interest in SFM investigations is to determine macroscopic material constants, such as the friction coefficient, on a microscopic scale. It has been shown that this is very difficult. To determine the influence of material parameters on the measured signals the interaction between the tip and the sample has to be examined. Because material properties are often not directly accessible and the measured signal depends nonlinearly on various parameters, it is necessary to compare simulations and measurements.When formulating a theory, one can have two sometimes contradicting aims: either one focuses on the behavior of the interaction between the tip and the sample or one is interested in explaining the results of a specific experimental setup. The first concept is represented by the theories of Hertz [10], Johnson et al. [11], Derjaguin et al. [12], and Maugis [13]. * Corresponding author These theories describe the interactions necessary to the understanding of the tip-sample system. The second concept is exemplified by the works of Burnham [14] and Rabe [15].Their goal is to compare computer simulations with a real experiment. The model for the SFM typically consists of a sphere or point mass representing the tip and a plane representing the sample. However, these simplifications often make a comparison between the theoretical and the measured results impossible. For example, the representation of the surface by a plane is not sufficient if the calculations should describe the dependence on topographical changes. Investigating surface properties, e.g. the adhesive force, on a corrugated sample, one notices that SFM images show a change in the properties correlated with topographical features. The adhesive force often decreases strongly at slopes even if the height differences at the surface are rather small (see SFM images in Fig. 1).It is interesting to explore whether these variations in the adhesive fo...

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“…For a detailed study of such blisters see [26]. The blisters are soft and seem to be filled with gas [26][27][28]. Applying a force of about 5-10 nN with the tip will flatten the blister.…”

Section: Experiments and Resultsmentioning

confidence: 99%

Influence of the topography on adhesion measured by SFM

Stifter¹,

Weilandt²,

Marti³

et al. 1998

Applied Physics A: Materials Science & Processing

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“…The electrolytic top-down fabrication of the electrode surface can lead to irreversible side reactions: electrolysis of water, production of carbon dioxide and the formation of nonconducting surface oxides. These reactions can contribute to irreversible behavior of carbon fiber electrodes [2,3,22]. However, solution composition, potential window, potential scan rate and waveform, used during surface fabrication, can be optimized to control these reactions [2,12].…”

Section: Electrochemical Characterization Of Electrodesmentioning

confidence: 99%

Electrode Kinetics and Sensitivity of Nanostructured Electrodes from Different Carbon Fiber Precursor Materials

2010

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Correlation of properties of common carbon fiber precursor materials, polyacrylonitrile (PAN) and pitch, with kinetics and sensitivity of microdisk electrodes, PAN T650, PAN HCB and Pitch P25, nanostructured by an electrochemical etching method was tested. Sensitivity of PAN electrodes is higher but kinetics are slower than at pitch electrodes due to more defects in PAN. Because of more surface oxides at PAN T650 adsorption of dopamine is greater than at PAN HCB electrodes but for uric acid adsorption is greater at PAN HCB. Uric acid sensitivity is related to high conductivity of PAN fibers, with an inverse relationship observed for dopamine.

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“…[17,181 This rate enhancement is attributed to an increase in the density of exposed graphitic edge plane carbon at the electrode surface following activation of basal plane HOPG, which initially showed slow electron-transfer properties. A recent study by Goss et al [21], which utilized atomic force microscopy, scanning electron microscopy and optical microscopy, provides further support for the importance of surface morphology for favorable electron-transfer rates. Therefore, a key factor in determining the macroscopic electron-transfer kinetics of many electrochemical probes at carbon electrodes appears to be the availability of edge plane carbon at the electrode surface.…”

Section: Introductionmentioning

confidence: 93%

“…[l, 21 One of the most widely used OTEs is based on the metal mesh materials. These materials are available with various optical transparencies as gold, platinum, copper and nickel meshes, and can be easily incorporated into the optically transparent thinlayer electrode (OTTLE) design.…”

Section: Introductionmentioning

confidence: 99%

Electron‐transfer properties of pyrolytic graphite optically transparent electrodes

Kummer¹,

Kirchhoff²

1996

Electroanalysis

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The electron-transfer characteristics of metal mesh optically transparent electrodes, which were modified by chemical vapor deposition of pyrolytic graphite, are investigated. The pyrolytic graphite optically transparent electrodes are found to exhibit sluggish electron-transfer toward several transition metal probes. Subsequent activation of the electrode surface is accomplished by RF plasma etching of the carbon layer to expose a higher density ofedge plane carbon. A limiting current response is achieved after 2.5 min of RF exposure. As a result of the activation process, sharper voltammograms and reduced peak separations are observed in cyclic voltammetric measurements, while reduced equilibration times are found for thin-layer spectroelectrochemical measurements.

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Imaging the incipient electrochemical oxidation of highly oriented pyrolytic graphite

Cited by 135 publications

References 21 publications

Influence of the topography on adhesion measured by SFM

Influence of the topography on adhesion measured by SFM

Electrode Kinetics and Sensitivity of Nanostructured Electrodes from Different Carbon Fiber Precursor Materials

Electron‐transfer properties of pyrolytic graphite optically transparent electrodes

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