Scanning tunneling microscopy studies of carbon-oxygen reactions on highly oriented pyrolytic graphite

Chang, Hsiangpin; Bard, Allen J.

doi:10.1021/ja00015a012

Cited by 203 publications

(162 citation statements)

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“…These latter particles are also active if the reaction activation barrier for carbon, which is substantially higher for carbon in the basal plane than for carbon at steps, is overcome. An example is the formation of etch pits on the basal plane, e.g., in carbon oxidation studies [23,39]. Our studies also point to etchinactive particles being catalytically active, as is discussed later on.…”

Section: Resultssupporting

confidence: 57%

Shedding light on the crystallographic etching of multi-layer graphene at the atomic scale

et al. 2009

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The controlled etching of graphite and graphene by catalytic hydrogenation is potentially a key engineering route for the fabrication of graphene nanoribbons with atomic precision. The hydrogenation mechanism, though, remains poorly understood. In this study we exploit the benefi ts of aberration-corrected high-resolution transmission electron microscopy to gain insight to the hydrogenation reaction. The etch tracks are found to be commensurate with the graphite lattice. Catalyst particles at the head of an etch channel are shown to be faceted and the angles between facets are multiples of 30°. Thus, the angles between facets are also commensurate with the graphite lattice. In addition, the results of a post-annealing step suggest that all catalyst particles even if they are not involved in etching are actively forming methane during the hydrogenation reaction. Furthermore, the data point against carbon dissolution being a key mechanism during the hydrogenation process.

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Section: Resultssupporting

confidence: 57%

Shedding light on the crystallographic etching of multi-layer graphene at the atomic scale

et al. 2009

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“…A 1 mm diameter pBDD disk electrode, used for macroscale electrochemistry was prepared in house from DIAFILM EA grade material (Element Six Ltd.). 26,54 The average boron doping level of the pBDD material was ca. 5 × 10 20 atoms cm −3 , above the metallic threshold as confirmed by secondary ion mass spectrometry (SIMS).…”

Section: Materials and Solutionsmentioning

confidence: 99%

Electrochemical oxidation of dihydronicotinamide adenine dinucleotide (NADH): comparison of highly oriented pyrolytic graphite (HOPG) and polycrystalline boron-doped diamond (pBDD) electrodes

Maddar

Lazenby

Patel

et al. 2016

Phys. Chem. Chem. Phys.

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(2016) Electrochemical oxidation of dihydronicotinamide adenine dinucleotide (NADH) : Comparison of highly oriented pyrolytic graphite (HOPG) and polycrystalline boron-doped diamond (pBDD) electrodes. Physical Chemistry Chemical Physics. Permanent WRAP URL:http://wrap.warwick.ac.uk/81637 Copyright and reuse:The Warwick Research Archive Portal (WRAP) makes this work of researchers of the University of Warwick available open access under the following conditions. Copyright © and all moral rights to the version of the paper presented here belong to the individual author(s) and/or other copyright owners. To the extent reasonable and practicable the material made available in WRAP has been checked for eligibility before being made available.Copies of full items can be used for personal research or study, educational, or not-for-profit purposes without prior permission or charge. Provided that the authors, title and full bibliographic details are credited, a hyperlink and/or URL is given for the original metadata page and the content is not changed in any way. The electro-oxidation of nicotinamide adenine dinucleotide (NADH) is studied at bare surfaces of highly oriented pyrolytic graphite (HOPG) and semi-metallic polycrystalline boron-doped diamond (pBDD). A comparison of these two carbon electrode materials is interesting because they possess broadly similar densities of electronic states that are much lower than most metal electrodes, but graphite has carbon sp 2 -hybridization, while in diamond the carbon is sp 3 -hybridised, with resulting major differences in bulk structure and surface termination. Using cyclic voltammetry (CV), it is shown that NADH oxidation is facile at HOPG surfaces but the reaction products tend to strongly adsorb, which causes rapid deactivation of the electrode activity. This is an important factor that needs to be taken into account when assessing HOPG and its intrinsic activity. It is also shown that NADH itself adsorbs at HOPG, a fact that has not been recognized previously, but has implications for understanding the mechanism of the electro-oxidation process. Although pBDD was found to be less susceptible to surface fouling, pBDD is not immune to deterioration of the electrode response, and the reaction showed more sluggish kinetics on this electrode. Scanning electrochemical cell microscopy (SECCM) highlights a significant voltammetric variation in electroactivity between different crystal surface facets that are presented to solution with a pBDD electrode. The electroactivity of different grains correlates with the local dopant level, as visualized by field emission-scanning electron microscopy. SECCM measurements further prove that the basal plane of HOPG has high activity towards NADH electro-oxidation. These new insights on NADH voltammetry are useful for the design of optimal carbon-based electrodes for NADH electroanalysis.

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“…The impact energy of the clusters (in the range 1.0 -5.5 keV) was determined by a bias voltage applied to the sample during deposition. The cluster implantation depths (more specifically, the damage track depths) were obtained by the etching method [17][18][19][20][21][22][23]. Thus the samples were etched in air at 650 C for a duration of 3-5 min immediately after removal from the vacuum.…”

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confidence: 99%

Scaling Relations for Implantation of Size-Selected Au, Ag, and Si Clusters into Graphite

et al. 2003

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Scanning tunneling microscopy studies of carbon-oxygen reactions on highly oriented pyrolytic graphite

Cited by 203 publications

References 1 publication

Shedding light on the crystallographic etching of multi-layer graphene at the atomic scale

Shedding light on the crystallographic etching of multi-layer graphene at the atomic scale

Electrochemical oxidation of dihydronicotinamide adenine dinucleotide (NADH): comparison of highly oriented pyrolytic graphite (HOPG) and polycrystalline boron-doped diamond (pBDD) electrodes

Scaling Relations for Implantation of Size-Selected Au, Ag, and Si Clusters into Graphite

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