A facile approach for quantifying the density of defects (edge plane sites) of carbon nanomaterials and related structures

Abstract

A facile methodology based on cyclic voltammetry is presented allowing the density of defects, viz edge plane like-sites/defects of carbon nanomaterials to be readily quantified. The approach is based on the construction of carbon nanomaterial paste electrodes which is measured using cyclic voltammetry and a standard electrochemical redox probe. This protocol allows a quantitative relationship between the heterogeneous electron-transfer rate and the density of defects to be readily determined and also provides researchers with a methodology to quantify the density of defects for comparative purposes.

3D Printed Graphene Based Energy Storage Devices

“…Therefore, it is commonly understood that the k 0 obs  = k 0 edge ( θ edge ), where θ edge, is the amount of edge sites present on the electrode surface as reported by Hallam et al . and Davies et al 2425…”

“…Interestingly, when the filament is in its bulk form the voltammetric responses exhibit sigmoidal behaviour (especially at lower scan rates), however upon printing of a 3DE the voltammetry demonstrates a quasi -reversible system over the chosen scan rates (5–500 mV s −1 ), as the peak-to-peak separation is over that of 59 mV. Further analysis of this data was carried out in the form of a plot of log 10 I p vs. log 10 ν for the graphene/PLA and printed 3DE, exhibiting gradients of 0.44 and 0.42 respectively, where such values are expected for the case of a semi-infinite diffusion model, with no presence from thin-layer effects24. The heterogeneous rate transfer constants, k 0 obs , were deduced using both electrode platforms (as described in the Methods section).…”

Sustainable monitoring of Zn(II) in biological fluids using office paper

“…2G, H, and F, all the SPEs are consistent with a linear log (peak current) vs. log (scan rate) dependence. The slopes are close to 0.5, in agreement with Randles-Sevcik equation [28]. 3) In order to estimate the active area of the different substrates utilized, chronoamperometric experiments in presence of different concentrations of ferricyanide were performed and Cottrell equation, i = nFAD 0.5 C/ 0.5 t 0.5 [26], was used.…”

Prussian Blue Modified Solid Carbon Nanorod Whisker Paste Composite Electrodes: Evaluation towards the Electroanalytical Sensing ofH2O2

“…The relative density of the electroactive edge plane sites has been calculated from cyclic voltammetry measurements and was found to be ca. 13.3% being much higher than for the other forms of carbon materials [21]. Mineral oil (suitable for the preparation of Nujol mulls for IR, stabilizer free) to prepare carbon nanotube paste electrodes was obtained from Sigma-Aldrich.…”

“…In that study, hydrogen peroxide was selected as one of model compounds since its detection is often needed, for example, in studying oxidative stress in bio-systems [13,14], low temperature fuel cell processes, [15,16] and in the studies of corrosion processes [17,18]. Paste electrodes, as selected in this study, as working electrodes are useful because they (1) are simple to prepare and handle, (2) demonstrate reasonable reproducibility, (3) have a low background current, (4) can be easily recleaned, (5) have a low cost, (6) can be used in a wide potential range [19,20], and (7) minimise diffusion within the nano material network neglecting the influence of thin layer diffusion allowing more readily to determine the charge transfer rate constants via cyclic voltammetry [21]. Also they can be easily modified with analyte-specific enzymes or redox mediators [19,20].…”