Heterogeneous Charge Transfer at the Amorphous Carbon/Solution Interface: Effect on the Spontaneous Attachment of Aryldiazonium Salts

Murphy, David J.; Cullen, Ronan J.; Jayasundara, Dilushan R.; Doyle, Richard L.; Lyons, Michael E. G.; Colavita, Paula E.

doi:10.1021/jp406686e

Cited by 11 publications

(8 citation statements)

References 52 publications

(140 reference statements)

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“…The high binding energy edge was used to calculate work function values (f), which are summarised in Table 1. The work function of a-C at 4.69 eV is in good agreement with previous reports on magnetron sputtered carbon 18,33 and close to values quoted for graphitic nitrogen-free materials such as graphite (4.4 eV) 34,35 and glassy carbon (4.6 eV). 35 Incorporation of nitrogen results in an increase of work function values which fall in the range 4.82-4.94 eV; these values are above those of a-C but below those reported for O-terminated sputtered carbons (5.1 eV).…”

Section: Resultssupporting

confidence: 91%

Capacitive storage at nitrogen doped amorphous carbon electrodes: structural and chemical effects of nitrogen incorporation

et al. 2019

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Section: Resultssupporting

confidence: 91%

Capacitive storage at nitrogen doped amorphous carbon electrodes: structural and chemical effects of nitrogen incorporation

et al. 2019

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“…Our study provides no other information on the nature of the surface interaction; however, it is interesting to note that spontaneous grafting of aryldiazonium ions to carbon nanotubes, − amorphous carbons, , and graphene has been studied in detail, and a two-step mechanism has been proposed. In the first step, an electron transfer mediated adsorption yields a reduced aryldiazonium species.…”

Section: Discussionmentioning

confidence: 91%

Electrografting of 4-Nitrobenzenediazonium Ion at Carbon Electrodes: Catalyzed and Uncatalyzed Reduction Processes

et al. 2016

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Cyclic voltammograms for the reduction of aryldiazonium ions at glassy carbon electrodes are often, but not always, reported to show two peaks. The origin of this intriguing behavior remains controversial. Using 4-nitrobenzenediazonium ion (NBD), the most widely studied aryldiazonium salt, we make a detailed examination of the electroreduction processes in acetonitrile solution. We confirm that deposition of film can occur during both reduction processes. Film thickness measurements using atomic force microscopy reveal that multilayer films of very similar thickness are formed when reduction is carried out at either peak, even though the film formed at the more negative potential is significantly more blocking to solution redox probes. These and other aspects of the electrochemistry are consistent with the operation of a surface-catalyzed reduction step (proceeding at a clean surface only) followed by an uncatalyzed reduction at a more negative potential. The catalyzed reduction proceeds at both edge-plane and basal-plane graphite materials, suggesting that particular carbon surface sites are not required. The unusual aspect of aryldiazonium ion electrochemistry is that unlike other surface-catalyzed reactions, both processes are seen in a single voltammetric scan at an initially clean electrode because the conditions for observing the uncatalyzed reaction are produced by film deposition during the first catalyzed reduction step.

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“…The materials discussed in the previous section offer an opportunity to investigate the effect of graphitic cluster organization on the response of a solid carbon electrode with controlled N-functional group type and concentration, while allowing to discriminate contributions arising from the presence of N-functionalities at the surface. In this context, redox couples have been used as probes of carbon electrode properties by our group and others in the literature. ,, To probe the effect of surface nanostructuring on the electrochemical response of nitrogenated graphitic carbons, we selected a catechol species as a redox probe, as these are known to be surface-sensitive and adsorb onto carbon electrodes. ,, …”

Section: Resultsmentioning

confidence: 99%

“…In this context, redox couples have been used as probes of carbon electrode properties by our group and others in the literature. 5,43,44 To probe the effect of surface nanostructuring on the electrochemical response of nitrogenated graphitic carbons, we selected a catechol species as a redox probe, as these are known to be surface-sensitive and adsorb onto carbon electrodes. 17,18,44 Catechols display redox chemistry that is highly sensitive to surface preparations, ranging from polishing and cleaning protocols to modification with adlayers.…”

Section: Experimental Methodsmentioning

confidence: 99%

Experimental and Computational Study of Dopamine as an Electrochemical Probe of the Surface Nanostructure of Graphitized N-Doped Carbon

et al. 2018

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N-doped carbon nanomaterials have received increased attention from electrochemists due to their applications in the metal-free electrocatalysis of important redox processes. In this work, a series of graphitized undoped and nitrogen-doped carbon electrodes prepared by thermal annealing of sputtered amorphous carbon films were prepared and characterized using a combination of X-ray photoelectron spectroscopy and Raman spectroscopy. Adsorption of the surface-sensitive redox probe dopamine at each electrode surface was then studied using cyclic voltammetry and the results correlated to the physico-chemical characterisation. Results indicate that dopamine adsorption is influenced by both the nitrogen surface chemistry and the degree of graphitization of the carbon scaffold. N-doping, with predominantly graphitic-N sites, was found to increase adsorption of dopamine more than 6 fold on carbon surfaces when the introduction of N atoms did not result in substantial alterations to the sp 2 network. However, when an identical type and level of N-doping is accompanied by a significant increase in disorder in the carbon scaffold, adsorption is limited to levels comparable to those of nitrogen-free carbon. Density functional theory studies of dopamine adsorption on graphene and N-doped graphene model surfaces showed that dopamine interacts via π-stacking at the graphene surface. The Gibbs free energy of adsorption on N-doped graphenes were estimated at 12-13 kcal mol-1 , and found to be approximately twice that of undoped graphenes. Results suggest that chemical changes resulting from N-doping enhance adsorption; however, high coverage values depend on the availability of sites for π-stacking. Therefore, the structurally disruptive effects of N-incorporation can significantly depress the dopamine response by limiting the availability of basal sites, ultimately dominating the overall electrochemical response of the carbon electrode.

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Heterogeneous Charge Transfer at the Amorphous Carbon/Solution Interface: Effect on the Spontaneous Attachment of Aryldiazonium Salts

Cited by 11 publications

References 52 publications

Capacitive storage at nitrogen doped amorphous carbon electrodes: structural and chemical effects of nitrogen incorporation

Capacitive storage at nitrogen doped amorphous carbon electrodes: structural and chemical effects of nitrogen incorporation

Electrografting of 4-Nitrobenzenediazonium Ion at Carbon Electrodes: Catalyzed and Uncatalyzed Reduction Processes

Experimental and Computational Study of Dopamine as an Electrochemical Probe of the Surface Nanostructure of Graphitized N-Doped Carbon

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