Probing the charging mechanisms of carbon nanomaterial polyelectrolytes

Hodge, Stephen; Tay, Hui Huang; Anthony, David B.; Menzel, Robert; Buckley, David J.; Cullen, Patrick L.; Skipper, Neal T.; Howard, Christopher A.; Shaffer, Milo S. P.

doi:10.1039/c4fd00043a

Cited by 25 publications

(49 citation statements)

References 41 publications

(65 reference statements)

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“…However, at higher charge, the net electron− electron interactions increase/decrease during reduction 151 and oxidation, 265 respectively. As a result, the eDOS stretches (nonlinearly), increasing the magnitude of the potential for any given charge stoichiometry, relative to the neutral eDOS.…”

Section: Chemical Reviewsmentioning

confidence: 99%

“…For graphitic materials, both reductive (donor) and oxidative (acceptor) charging shift the Fermi level (Figure 16a), by adding electrons to the antibonding π*-band (conduction band) or removing them from the bonding π-band (valence band), respectively. The magnitude of the Fermi level shift is dependent on the reducing/oxidizing species, 214 the stoichiometry of the charging material, 151 and the eDOS of the specific nanomaterial (Figure 16b). In the charged state, the filled/emptied states may be probed spectroscopically or electrochemically.…”

Section: Chemical Reviewsmentioning

confidence: 99%

“…151 As the concentration of electrons in the CCN conduction band diminishes with grafting, the Fermi level drops until it is equal to the reduction potential of the reagent. Hence, by selecting reagents with less negative reduction potentials, the degree of functionalization can be improved, for example, the grafting ratios from alkyl halide functionalization following the trend of increasing with …”

Section: Mechanism Of Reductive Functionalizationmentioning

confidence: 99%

“…As a result, the eDOS stretches (nonlinearly), increasing the magnitude of the potential for any given charge stoichiometry, relative to the neutral eDOS. While this effect has not yet been studied in detail for CCNs, quantum capacitance concepts have been used to estimate the extent of the effect for both graphenide 151 and nanotubide, 266,267 though the band structure may change more significantly upon heavy doping or due to dopant-related features.…”

Section: Chemical Reviewsmentioning

confidence: 99%

“…63 Most commonly, CCNs are discharged by exposure to ambient conditions, although a number of other strategies have been explored. Reactions with ambient water may evolve hydrogen, producing alkali metal hydroxide as a byproduct, 151 which is easily removed by washing. Similarly, the fullerides and fullereniums discharge upon exposure to oxygen, with the residual charge(s) electronically oxidized/reduced returning the neutral, undamaged fullerene.…”

Section: Discharging Ccnsmentioning

confidence: 99%

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Charged Carbon Nanomaterials: Redox Chemistries of Fullerenes, Carbon Nanotubes, and Graphenes

et al. 2018

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Since the discovery of buckminsterfullerene over 30 years ago, sp 2 -hybridised carbon nanomaterials (including fullerenes, carbon nanotubes, and graphene) have stimulated new science and technology across a huge range of fields. Despite the impressive intrinsic properties, challenges in processing and chemical modification continue to hinder applications. Charged carbon nanomaterials (CCNs), formed via the reduction or oxidation of these carbon nanomaterials, facilitate dissolution, purification, separation, chemical modification, and assembly. This approach provides a compelling alternative to traditional damaging and restrictive liquid phase exfoliation routes. The broad chemistry of CCNs not only provides a versatile and potent means to modify the properties of the parent nanomaterial but also raises interesting scientific issues. This review focuses on the fundamental structural forms: buckminsterfullerene, single-walled carbon nanotubes, and single-layer graphene, describing the generation of their respective charged nanocarbon species, their interactions with solvents, chemical reactivity, specific (opto)electronic properties, and emerging applications. CONTENTS

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Section: Chemical Reviewsmentioning

confidence: 99%

Section: Chemical Reviewsmentioning

confidence: 99%

Section: Mechanism Of Reductive Functionalizationmentioning

confidence: 99%

Section: Chemical Reviewsmentioning

confidence: 99%

Section: Discharging Ccnsmentioning

confidence: 99%

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Charged Carbon Nanomaterials: Redox Chemistries of Fullerenes, Carbon Nanotubes, and Graphenes

et al. 2018

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Direct Measurement of Electron Transfer in Nanoscale Host–Guest Systems: Metallocenes in Carbon Nanotubes

McSweeney

Chamberlain

Baldoni

et al. 2016

Chemistry A European J

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Electron transfer processes play a significant role in host-guest interactions and determine physicochemical phenomena emerging at the nanoscale that can be harnessed in electronic or optical devices as well as biochemical and catalytic systems. We have developed a novel method for qualifying and quantifying the electronic doping of single walled carbon nanotubes (SWNT) using electrochemistry and have established a direct link between these experimental measurements and ab initio DFT calculations. Metallocenes such as cobaltocene and methylated ferrocene derivatives were encapsulated inside SWNT (1.4 nm diameter) and the cyclic voltammetry (CV) performed. The electron transfer between guest-molecules and host-SWNT is measured as a function of shift in the redox potential (E1/2) . Furthermore, the shift in E1/2 is shown to be inversely proportional to the nanotube diameter. For the quantification of the amount of electron transfer from the guestmolecules on the SWNT, a novel method using coulometry was developed allowing the mapping of the density of states (DOS) and the Fermi level of the SWNT. Correlated with theoretical calculations, coulometry provides an accurate indication of n/p-doping of the SWNT.

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Dual Behaviour of Amorphous Carbon Released Electrochemically from Graphite

Oliveira

Viana

Rego³

et al. 2016

ChemistrySelect

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Here we show that the main product released from graphite in the early stages of the anodic polarization is a carbon-based salt comprised of an amorphous carbonaceous material with delocalized negative charge, counterbalanced by sodium cations. Remarkably, this material shows a dual behaviour: it behaves as an electrolyte in aqueous medium, which has the ability to enhance the capacitive properties of the electrodesolution interface and in the solid state it can be used as an electrode material with meaningful capacitive properties.Although the electrochemical approach is one of the most successful synthetic methods for the top-down preparation of a wide spectrum of graphene particles with variable sizes and shapes, like sheets, [1][2][3][4][5] nanoribbons, [6] flakes [6][7][8] and quantum dots, [9][10][11] the nature of the species formed upon the electrochemical oxidation of graphite is still an unclear matter. A close reading of the literature reveals that there is no clear specification of the electrochemical conditions required to prepare selectively just one type of graphene-based material. Notwithstanding, it is known that the chemical composition of the electrolyte and water content of the medium have a crucial effect on the size of the carbon nanoparticles. [6,12,13] It is thus expected that a mixture of different graphene-based structures may be inevitably formed when the electrochemical synthesis is performed in aqueous medium, which explains the common lab practice of centrifugation and filtration after the electrochemical essays. Even though these operations are decisive to improve the selectivity of the production process, they inevitably mask the nature of the species formed. In order to overcome this constrain, the present work was initially motivated to clarify what type of carbon materials are released elec-trochemically from a graphite anode in the early stages of the electrode polarization. No separation process other than dialysis (to remove the electrolyte) was used. More importantly, this study lead us to the finding that the main type of carbon material generated at the anode shows unprecedent electrochemical properties when dissolved in aqueous medium: ability to behave as an electrolyte and to enhance the capacitive properties of the electrode-solution interface.The electrochemical oxidation of graphite was performed under experimental conditions adapted from the literature. [10,11] It was used a phosphate buffer solution (pH 7) and graphite rods as the anode and cathode electrodes. The anodic polarization was carried out under galvanostatic control. The solution removed from the anode compartment after one hour of electrode polarization was transparent and colourless and no visible signs of graphite expansion on the anode was observed. However, analysis of this solution by a Total Organic Carbon analyser (TOC) revealed a significant amount of carbon released from graphite during the galvanostatic polarization (typically 7-10 mg/L). Before further characterization, the anodic solution wa...

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Probing the charging mechanisms of carbon nanomaterial polyelectrolytes

Cited by 25 publications

References 41 publications

Charged Carbon Nanomaterials: Redox Chemistries of Fullerenes, Carbon Nanotubes, and Graphenes

Charged Carbon Nanomaterials: Redox Chemistries of Fullerenes, Carbon Nanotubes, and Graphenes

Direct Measurement of Electron Transfer in Nanoscale Host–Guest Systems: Metallocenes in Carbon Nanotubes

Dual Behaviour of Amorphous Carbon Released Electrochemically from Graphite

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