Enhancement of heterogeneous electron transfer dynamics tuning single-walled carbon nanotube forest height and density

Lamberti, Francesco; Ferraro, Davide; Giomo, Monica; Elvassore, Nicola

doi:10.1016/j.electacta.2013.02.119

Cited by 5 publications

(6 citation statements)

References 57 publications

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“…The CPE instead of the ideal capacitance, C dl , was used to better account for the capacitive behavior of the double-layer and the diffusion contribution. 51 R ct , which models interfacial electron transfer kinetics between the redox probe and the electrode surface, was considered as a function of IBA adsorption. R ct increased for longer IBA immersion times, as measurements were performed with a negatively charged redox probe, ferricyanide.…”

Section: Resultsmentioning

confidence: 99%

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Optoelectrochemical Biorecognition by Optically Transparent Highly Conductive Graphene-Modified Fluorine-Doped Tin Oxide Substrates

Lamberti

Brigo

Favaro

et al. 2014

ACS Appl. Mater. Interfaces

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Both optical and electrochemical graphene-based sensors have gone through rapid development, reaching high sensitivity at low cost and with fast response time. However, the complex validating biochemical operations, needed for their consistent use, currently limits their effective application. We propose an integration strategy for optoelectrochemical detection that overcomes previous limitations of these sensors used separately. We develop an optoelectrochemical sensor for aptamer-mediated protein detection based on few-layer graphene immobilization on selectively modified fluorine-doped tin oxide (FTO) substrates. Our results show that the electrochemical properties of graphene-modified FTO samples are suitable for complex biological detection due to the stability and inertness of the engineered electrodic interface. In addition, few-layer immobilization of graphene sheets through electrostatic linkage with an electrochemically grafted FTO surface allows obtaining an optically accessible and highly conductive platform. As a proof of concept, we used insulin as the target molecule to reveal in solution. Because of its transparency and low sampling volume (a few microliters), our sensing unit can be easily integrated in lab-on-a-chip cell culture systems for effectively monitoring subnanomolar concentrations of proteins relevant for biomedical applications.

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Section: Resultsmentioning

confidence: 99%

“…In particular, the R s value depends on the solution conductivity, while W module results from the redox probe diffusion through the surface layer. The CPE instead of the ideal capacitance, C dl , was used to better account for the capacitive behavior of the double-layer and the diffusion contribution …”

Section: Resultsmentioning

confidence: 99%

Optoelectrochemical Biorecognition by Optically Transparent Highly Conductive Graphene-Modified Fluorine-Doped Tin Oxide Substrates

Lamberti

Brigo

Favaro

et al. 2014

ACS Appl. Mater. Interfaces

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“…Improvement of both charge separation and charge transfer kinetics has also been observed for Au nanostructured needles . Such an effect for carbon microtubes covered with carbon nanocones has been attributed to the enhancement of the electrode/electrolyte interfacial area . Accordingly, the very significant surface increase and dominating sp 2 nature of the more charge-conducting CC bonds obtained after the CHR treatment, as evidenced by C dl , XPS, and Raman measurements, can explain the very low R CT value for CFP CHR in comparison to that of the other tested electrodes.…”

Section: Resultsmentioning

confidence: 76%

Electrical Field-Induced Hydrogen Generation at Electrochemically Grown Catalyst-Free Carbon Fiber Microstructures

Ezuz,

Kadosh,

Bochlin

et al. 2023

ACS Appl. Energy Mater.

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Simple cathodic treatments, conducted in an aqueous acidic solution and at hydrogen evolving potentials, are shown to form truncated cone-like microstructures on the surface of carbon fiber paper (CFP) electrodes. An effective ∼32-fold increase of effective surface area was determined for CFPs after consecutive cyclic voltammetry (CV) and chronopotentiometry (CHR) treatments as compared to untreated CFP. Moreover, this is accompanied, as determined by XPS and EIS techniques, by changes in surface chemistry toward a more dominating sp2 nature of the C–C bonds and a significant (∼270-fold) decrease of charge transfer resistance. Electrochemical observations, as well as numerical simulations, indicate that high electrical fields near the microstructures, arising from an applied potential on treated electrodes, increase local H+ concentrations, which can reach values in the order of ∼40- to ∼70-fold that of the bulk H+ concentration. This is shown to have a significant impact on the performance of the CFP-treated electrodes toward the important energy-related hydrogen evolution reaction (HER); the current density at −0.70 V vs RHE for a CV-treated CFP electrode can reach a value 70-fold higher than that of an untreated one (10.5 and 0.15 mA cm–2, respectively). An additional 10-fold current density increase related to effective surface increase can be achieved by a consecutive CHR treatment. Long-term stability was determined for such treated electrodes during H2 generation for 20 h in 1 M H2SO4 at a constant applied current density of 5.0 mA cm–2. It is anticipated that further development of the present concepts may lead to possible future use of such simply obtained structured electrodes in electrochemical energy conversion/storage devices.

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“…The results of EIS thus provide information about the electrode-electrolyte interface, i.e., the kinetics of the charge transfer mechanisms happening between WS2 and PANI, as well as about the electrode surface area. The experimental data are fitted using a Randles modified cell ( Nguyen and Breitkopf, 2018 ), choosing a constant phase element (CPE) for modeling the double layer capacitance and the Warburg element ( Lamberti et al, 2013 ): in this way the non-ideality of the whole system can be modeled emphasizing the role of each constituent in the composite electrode. In particular, Rs refers to the saturated resistance, Rct is the charge transfer resistance associated to the sodium cations discharge in the underlying GC electrode, the CPE1 is the associated double layer capacitance and CPE2 represents the Warburg element related to the semi-infinite linear diffusion of the ions from the electrolyte towards the electrode.…”

Section: Resultsmentioning

confidence: 99%

Nanostructured 2D WS2@PANI nanohybrids for electrochemical energy storage

et al. 2022

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2D materials are interesting flat nanoplatforms for the implementation of different electrochemical processes, due to the high surface area and tunable electronic properties. 2D transition metal dichalcogenides (TMDs) can be produced through convenient top-down liquid-phase exfoliation (LPE) methods and present capacitive behaviour that can be exploited for energy storage applications. However, in their thermodynamically stable 2H crystalline phase, they present poor electrical conductivity, being this phase a purely semiconducting one. Combination with conducting polymers like polyaniline (PANI), into nanohybrids, can provide better properties for the scope. In this work, we report on the preparation of 2D WS2@PANI hybrid materials in which we exploit the LPE TMD nanoflakes as scaffolds, onto which induce the in-situ aniline polymerization and thus achieve porous architectures, with the help of surfactants and sodium chloride acting as templating agents. We characterize these species for their capacitive behaviour in neutral pH, achieving maximum specific capacitance of 160 F/g at a current density of 1 A/g, demonstrating the attractiveness of similar nanohybrids for future use in low-cost, easy-to-make supercapacitor devices.

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Enhancement of heterogeneous electron transfer dynamics tuning single-walled carbon nanotube forest height and density

Cited by 5 publications

References 57 publications

Optoelectrochemical Biorecognition by Optically Transparent Highly Conductive Graphene-Modified Fluorine-Doped Tin Oxide Substrates

Optoelectrochemical Biorecognition by Optically Transparent Highly Conductive Graphene-Modified Fluorine-Doped Tin Oxide Substrates

Electrical Field-Induced Hydrogen Generation at Electrochemically Grown Catalyst-Free Carbon Fiber Microstructures

Nanostructured 2D WS2@PANI nanohybrids for electrochemical energy storage

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