Intrinsic electrochemical activity of single walled carbon nanotube–Nafion assemblies

Snowden, Michael E.; Edwards, Martin A.; Rudd, Nicola C.; Macpherson, Julie V.; Unwin, Patrick R.

doi:10.1039/c3cp44538k

Cited by 16 publications

(12 citation statements)

References 90 publications

(138 reference statements)

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“…The use of infused CNTs in an enzyme-immobilizing film is a highly effective method of increasing electrode surface area [26], yet only those CNTs that are electrically connected to the electrode surface contribute to electrocatalytic current. Additionally, only portions of the CNT surface may be electrochemically active [27][28][29][30][31]. Yet another important limitation is that not all the enzymes are able to communicate with or are "wired" to electrochemically active CNT sites.…”

Section: Introductionmentioning

confidence: 99%

Modeling Carbon Nanotube Connectivity and Surface Activity in a Contact Lens Biofuel Cell

Reid

Jones

Hickey

et al. 2016

Electrochimica Acta

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Biofuel cells are often limited by the current density produced by the cathode; this is especially true when such fuel cells are scaled down to fit a desired application. Herein, we created a computational model to examine the effects of carbon nanotube (CNT) connectivity and surface activity on the current density of a biofuel cell cathode. The model was motivated by the creation of a novel contact lens biofuel cell that, although more stable and biocompatible than previously reported designs, was cathode limited.The device produced a maximum current density of 22 ± 4 µA cm -2 , and a maximum power density of 2.4 ± 0.9 µW cm -2 (at 0.163 V) with an open-circuit voltage of 0.44 ± 0.08 V. Computational results showed that in a Nafion film containing 1.6% CNTs by volume, less than 20% of the CNT fibers were connected to the electrode, assuming a planar electrode. The simulations predicted that a three-fold increase in CNT loading would lead to a roughly two-fold increase in total CNT connectivity. The simulations further estimated that for the CNTs connected to the electrode, only 21% of their sidewalls were contributing to cathodic current, meaning that the remaining surfaces were not electrochemically active. Given the low bilirubin oxidase (BOD) enzyme surface concentration, which was experimentally found to be 1.24 x 10 -13 mol cm -2 , it is likely that large portions of the CNT surfaces are not connected to enzymes. This result validates the push by the research community to increase BOD and laccase adsorption/orientation to CNT surfaces.

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Section: Introductionmentioning

confidence: 99%

Modeling Carbon Nanotube Connectivity and Surface Activity in a Contact Lens Biofuel Cell

Reid

Jones

Hickey

et al. 2016

Electrochimica Acta

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“…Recently, the group of Unwin have studied CV recorded in Nanoscale electrodes in a walled carbon channel experimentally [42]. They have also numerially studied systems that are dominated by diffusion [43,44] using finite element solver which eliminates the problem posed by irregular 45 geometries. In addition, the study in their paper [45] has introduced flow into an electrochemical system for the study of linear sweep voltammetry (LSV).…”

Section: Introductionmentioning

confidence: 99%

Experimentation and numerical modeling of cyclic voltammetry for electrochemical micro-sized sensors under the influence of electrolyte flow

Adesokan

Quan

Evgrafov

et al. 2016

Journal of Electroanalytical Chemistry

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(2016). Experimentation and numerical modeling of cyclic voltammetry for electrochemical micro-sized sensors under the influence of electrolyte flow. Journal of Electroanalytical Chemistry, 763(February), 141-148. DOI: 10.1016141-148. DOI: 10. /j.jelechem.2015 exchange current density leads to a shift in the peak current of the recorded CV.Finally, the results also demonstrate that the working electrode at the center of the fluidic cell records accurate measurement than placing the electrode at the bottom of the cell. The numerical results and the experimental data show both qualitative and quantitative good agreement.

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“…Nafion membranes find applications in electrochemical devices such as fuel cells chlor‐alkali cells, solar fuel generators and redox flow batteries . Apart from membranes, thin films of Nafion are used as coating material on modified electrodes for applications in glucose sensors, microbial biosensor for phenolic compounds, methanol sensors and other electrochemical applications such as the detection of glutathione, biosensors and detection of heavy metals . The structural and transport properties of the commercial Nafion membranes of various equivalent weights and thickness have been studied extensively .…”

Section: Introductionmentioning

confidence: 99%

Excited‐State Proton Transfer and Conformational Relaxation of 2‐(4′‐Pyridyl)benzimidazole in Nafion Films

2016

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The effect of annealing on the acidity and water uptake of Nafion films has been studied by using the acidity sensing fluorophore 2-(4'-pyridyl)benzimidazole (4PBI). The difference in acidity and the microenvironment of the fluorophore in annealed and nonannealed films is brought out in this study. The annealed film is found to have less water uptake than nonannealed films. The amount of water uptake increases upon acid treatment of the films, as all the steady-state and time-resolved behaviour of the molecule in nonannealed films is restored. These observations are rationalised by the formation of anhydrides upon annealing and their hydrolysis to sulfonic acid groups upon acid treatment. Interestingly, the acidity of annealed films is found to be even less than that of Na exchanged films, indicating that annealing removes more protons from the Nafion films than cation exchange can.

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Intrinsic electrochemical activity of single walled carbon nanotube–Nafion assemblies

Abstract: The intrinsic electrochemical properties and activity of single walled carbon nanotube (SWNT) network electrodes modified by a drop-cast Nafion film have been determined using the one electron oxidation of ferrocene trimethyl ammonium 3

Cited by 16 publications

References 90 publications

Modeling Carbon Nanotube Connectivity and Surface Activity in a Contact Lens Biofuel Cell

Modeling Carbon Nanotube Connectivity and Surface Activity in a Contact Lens Biofuel Cell

Experimentation and numerical modeling of cyclic voltammetry for electrochemical micro-sized sensors under the influence of electrolyte flow

Excited‐State Proton Transfer and Conformational Relaxation of 2‐(4′‐Pyridyl)benzimidazole in Nafion Films

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