In-situ Raman spectroscopy to elucidate the influence of adsorption in graphene electrochemistry

Beld, Wesley T. E. van den; Odijk, Mathieu; Vervuurt, René H. J.; Weber, JW Jan-Willem; Bol, Ageeth A.; Berg, Albert van den; Eijkel, Jan C.T.

doi:10.1038/srep45080

Cited by 29 publications

(17 citation statements)

References 40 publications

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“…[56][57][58][59][60][61] We focus on the ET kinetics of [Ru(NH3)6] 3+/2+ , a classic example of OS-ET, [62][63][64][65][66] which has been used for studies of outer sphere electrochemistry at graphene, 38,67 and does not adsorb on graphene at a detectable level. 68 We establish that the ET rate is in the order monolayer > bilayer > multilayer graphene on copper. Data for monolayer and bilayer graphene are rationalized in the context of a predominantly adiabatic mechanism, where the addition of subsequent graphene layers increases the effective barrier, by partially screening the electrode potential.…”

Section: Introductionmentioning

confidence: 83%

Adiabatic versus Non-Adiabatic Electron Transfer at 2D Electrode Materials

Liu¹,

Kang²,

Perry³

et al. 2021

Preprint

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<div><div><div><p>Outer-sphere electron transfer (OS-ET) is a cornerstone elementary electrochemical reaction, yet microscopic understanding is largely based on idealized theories, developed in isolation from experiments that themselves are often close to the kinetic (diffusion) limit. Focusing on graphene as-grown on a copper substrate as a model 2D material/metal-supported electrode system, this study resolves the key electronic interactions in OS-ET, and identifies the role of graphene in modulating the electronic properties of the electrode/electrolyte interface. An integrated experimental-theoretical approach combining co-located multi-microscopy, centered on scanning electrochemical cell microscopy (SECCM), with Raman microscopy and field emission-scanning electron microscopy, together with rate theory and density functional theory calculations is used to address OS-ET kinetics of hexaamineruthenium (III/II) chloride, [Ru(NH3)6]3+/2+. The experimental methodology allows spatially-resolved electrochemical measurements to be targeted at distinct regions of monolayer, bilayer and multilayer graphene on copper, with high diffusion rates, to reveal ET kinetics in the order: monolayer > bilayer > multilayer. Theoretical and computational methods combining the Schmickler-Newns-Anderson model, transition state theory, and constant potential DFT reveal that the difference in kinetics at monolayer and bilayer graphene can be rationalized in the context of a dominantly adiabatic mechanism, where the addition of subsequent graphene layers increases the contact potential, producing an increase in the effective barrier to electron transfer. This study provides a roadmap for the integration of experiments and theory in order to understand the nature of heterogeneous electron transfer at complex nanostructured electrode materials.</p></div></div></div>

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Section: Introductionmentioning

confidence: 83%

Adiabatic versus Non-Adiabatic Electron Transfer at 2D Electrode Materials

Liu¹,

Kang²,

Perry³

et al. 2021

Preprint

View full text Add to dashboard Cite

show abstract

“…[58][59][60][61][62][63] We focus on the ET kinetics of [Ru(NH3)6] 3+/2+ , a classic example of OS-ET, [64][65][66][67][68] which has been used for studies of outer sphere electrochemistry at graphene, 40,69 and does not adsorb on graphene at a detectable level. 70 We establish that the ET rate is in the order monolayer > bilayer > multilayer graphene on copper. Data for monolayer and bilayer graphene are rationalized from theory and simulations, which indicate a predominantly adiabatic mechanism, where the addition of subsequent graphene layers increases the effective barrier, by partially screening the electrode potential.…”

Section: Introductionmentioning

confidence: 83%

Adiabatic versus Non-Adiabatic Electron Transfer at 2D Electrode Materials

Liu¹,

Kang²,

Perry³

et al. 2021

Preprint

View full text Add to dashboard Cite

<div><div><div><p>Outer-sphere electron transfer (OS-ET) is a cornerstone elementary electrochemical reaction, yet microscopic understanding is largely based on idealized theories, developed in isolation from experiments that themselves are often close to the kinetic (diffusion) limit. Focusing on graphene as-grown on a copper substrate as a model 2D material/metal-supported electrode system, this study resolves the key electronic interactions in OS-ET, and identifies the role of graphene in modulating the electronic properties of the electrode/electrolyte interface. An integrated experimental-theoretical approach combining co-located multi-microscopy, centered on scanning electrochemical cell microscopy (SECCM), with Raman microscopy and field emission-scanning electron microscopy, together with rate theory and density functional theory (DFT) calculations is used to address OS-ET kinetics of hexaamineruthenium (III/II) chloride, [Ru(NH3)6]3+/2+. The experimental methodology allows spatially-resolved electrochemical measurements to be targeted at distinct regions of monolayer, bilayer and multilayer graphene on copper, with high diffusion rates, to reveal ET kinetics in the order: monolayer > bilayer > multilayer. To rationalize these findings we extended the Schmickler-Newns-Anderson model Hamiltonian for electron transfer and parametrized it using constant potential DFT. Combining this model with rate theory reveals that the difference in kinetics at monolayer and bilayer graphene can be rationalized in the context of a dominantly adiabatic mechanism, where the addition of subsequent graphene layers increases the contact potential, producing an increase in the effective barrier to electron transfer. This study provides a roadmap for the integration of experiments, theory, and simulations in order to understand the nature of heterogeneous electron transfer at complex nanostructured electrode materials.</p></div></div></div>

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“…Regarding the electrode material, ferrocyanide redox reaction can be considered either typical outer-sphere electron transfer reaction, with fast electron transfer not requiring strong interaction with the electrode surface, and controlled by mass transport of redox active species toward/from the electrode surface, 32,33 or behave as an inner-sphere redox probe, requiring a strong interaction with the electrode surface in order to exchange electrons, causing slower reaction. 34,35 Impedance spectra recorded with a bare glassy carbon electrode and at different concentrations of ferrocyanide are shown in the Nyquist plots of Figure 1. Changes on the spectra are observed as ferrocyanide concentration increases.…”

Section: Ferrocyanidementioning

confidence: 99%

Evaluation of multiple linear regression applied to impedimetric sensing

Rodrigues

Fragoso

Lemos

2020

Journal of Chemometrics

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In this work, the application of multiple linear regression (MLR) on the development of electroanalytical methods based on electrochemical impedance spectroscopy (EIS) data was investigated. This approach was proposed considering that more than one element of the equivalent electrical circuit fitted to impedance spectra could keep linear relationship with the analyte concentration and be used in a multivariate calibration model, rather than using only one element of the circuit in a univariate regression, the benchmark procedure in the context of impedimetric (bio)sensing. First, MLR was evaluated in the individual determination of the redox probe ferrocyanide in aqueous solutions, followed by the determination of catechol and hydroquinone in tap water samples. MLR produced better predictions than univariate regression when more complex electrochemical systems (catechol and hydroquinone) and more complex samples (tap water) were analyzed. The determinations of hydroquinone and catechol in the direct analysis of spiked tap water samples were successful, with apparent recoveries ranging from 94% to 136%.

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In-situ Raman spectroscopy to elucidate the influence of adsorption in graphene electrochemistry

Cited by 29 publications

References 40 publications

Adiabatic versus Non-Adiabatic Electron Transfer at 2D Electrode Materials

Adiabatic versus Non-Adiabatic Electron Transfer at 2D Electrode Materials

Adiabatic versus Non-Adiabatic Electron Transfer at 2D Electrode Materials

Evaluation of multiple linear regression applied to impedimetric sensing

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