Kinetic Modulation of Outer-Sphere Electron Transfer Reactions on Graphene Electrode with a Sub-surface Metal Substrate

Hui, Jingshu; Zhou, Xuan; Bhargava, Richa; Chinderle, Adam J.; Zhang, Jiarui; Rodríguez‐López, Joaquín

doi:10.1016/j.electacta.2016.06.134

Cited by 46 publications

(52 citation statements)

References 58 publications

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“…• 100% (2) where Is and Im are the average intensities of the selected areas (typically ~100 μm 2 ) on the substrate and 2D material, respectively.…”

Section: Optical Contrast Measurementmentioning

confidence: 99%

Optimising the visibility of graphene and graphene oxide on gold with multilayer heterostructures

et al. 2018

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Metals have been increasingly used as substrates in devices based on two-dimensional (2D) materials. However, the high reflectivity of bulk metals results in low optical contrast (<3%) and therefore poor visibility of transparent mono- and few-layer 2D materials on these surfaces. Here we demonstrate that by engineering the complex reflectivity of a purpose-designed multilayer heterostructure composed of thin Au films (2-8 nm) on SiO/Si substrate, the optical contrast of graphene and graphene oxide (GO) can be significantly enhanced in comparison to bulk Au, up to about 3 and 5 times, respectively. In particular, we achieved ∼17% optical contrast for monolayer GO, which is even 2 times higher than that on bare SiO/Si substrate. The experimental results are in good agreement with theoretical simulations. This concept is demonstrated for Au, but the methodology is applicable to other metals and can be adopted to design a variety of high-contrast metallic substrates. This will facilitate research and applications of 2D materials in areas such as plasmonics, photonics, catalysis and sensors.

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“…• 100% (2) where Is and Im are the average intensities of the selected areas (typically ~100 μm 2 ) on the substrate and 2D material, respectively.…”

Section: Optical Contrast Measurementmentioning

confidence: 99%

Optimising the visibility of graphene and graphene oxide on gold with multilayer heterostructures

et al. 2018

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“…24 Gold subsurface also enhances the charge transfer by a factor of about 5 due to electronic coupling between the layer and the gold. 25 The high sensitivity of the charge transfer to the sublayer and to the redox mediator is similarly observed on graphene oxide (GO) and on reduced graphene oxide (r-GO). …”

Section: Redox Mediator Charge Transfersmentioning

confidence: 93%

Localized electrochemistry for the investigation and the modification of 2D materials

Jaouen

Henrotte

Campidelli

et al. 2017

Applied Materials Today

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“…Depending on the electrode reaction, consideration needs to the effect of atmospheric contamination or exposure to ambient conditions, of the graphene sample. 16,36,38,66,84,95 An important point to bear in mind for SECCM studies of graphene, 36,38 and also for other local electrochemical measurements, 23,29 is that because all of the different structural motifs are assessed on the same sample, they all have the same history. The [Ru(NH3)6] 3+/2+ process displays fast kinetics on carbon electrode materials even after extensive exposure to ambient atmosphere, 66,95,96 and so we can be confident in the ratio of ET kinetics measured at monolayer and bilayer graphene for comparison to theory.…”

Section: Preparation Of Cvd Graphenementioning

confidence: 99%

“…33,34 Many previous electrochemistry studies of graphene (both exfoliated and grown by chemical vapor deposition) have considered material transferred to a Si/SiO2 surface. 23,29,[35][36][37][38][39][40][41][42][43] The study of graphene as-grown on copper not only allows back contact for electrochemistry, 27 but negates the need for polymeric transfer to a substrate, which may significantly contaminate the graphene surface and the resulting electrochemistry. 44 Furthermore, as-grown graphene on copper presents small islands of bilayer and multilayer graphene 45,46 on a contiguous monolayer of graphene/copper.…”

Section: Introductionmentioning

confidence: 99%

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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Kinetic Modulation of Outer-Sphere Electron Transfer Reactions on Graphene Electrode with a Sub-surface Metal Substrate

Cited by 46 publications

References 58 publications

Optimising the visibility of graphene and graphene oxide on gold with multilayer heterostructures

Optimising the visibility of graphene and graphene oxide on gold with multilayer heterostructures

Localized electrochemistry for the investigation and the modification of 2D materials

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

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