Conductive supports for combined AFM–SECM on biological membranes

Frederix, P. L. T. M.; Bosshart, Patrick D.; Akiyama, T.; Chami, Mohamed; Gullo, Maurizio R.; Blackstock, Jason J.; Dooleweerdt, Karin; Rooij, N. F. de; Staufer, U.; Engel, Andréas

doi:10.1088/0957-4484/19/38/384004

Cited by 60 publications

(90 citation statements)

References 52 publications

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“…This has been found recently for a diversity of electrochemical processes at HOPG surfaces with a wide range of step densities. 40,49,50 Moreover, microscopic and nanoscopic measurements have reported high intrinsic activity of the basal surface, 40,41,49,[51][52][53][54][55] in contrast with the earlier literature, which proposed that the basal surface of HOPG was inert or largely inert. 56,57 In this paper we report detailed investigations of the adsorption and electrochemistry of AQDS on HOPG, with the particular goal of elucidating whether it is an appropriate measure for determining step edge density.…”

Section: Introductionmentioning

confidence: 79%

“…Thus, the electrochemistry of adsorbed AQDS at HOPG is analogous to that seen recently for other reactions: it is dominated by the basal surface. 37,40,41,[49][50][51][52][53][54][55] Time-resolved adsorption measurements: structure-activity analysis SECCM allows electrochemical measurements to be performed almost immediately after meniscus contact with the surface. 68 Coupled with the analysis of surface-bound redox species via FSCV, this allowed relatively fast adsorption to be followed in real-time.…”

Section: Impact Of Hopg Step Density On Adsorbed Electroactive Aqdsmentioning

confidence: 99%

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Molecular Functionalization of Graphite Surfaces: Basal Plane versus Step Edge Electrochemical Activity

et al. 2014

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The chemical functionalization of carbon surfaces has myriad applications, from tailored sensors to electrocatalysts. Here, the adsorption and electrochemistry of anthraquinone-2,6-disulfonate (AQDS) is studied on highly oriented pyrolytic graphite (HOPG) as a model sp 2 surface. A major focus is to elucidate whether adsorbed electroactive AQDS can be used as a marker of step edges, which have generally been regarded as the main electroactive sites on graphite electrode surfaces. First, the macroscopic electrochemistry of AQDS is studied on a range of surfaces differing in step edge density by more than 2 orders of magnitude, complemented with ex-situ tapping mode atomic force microscopy (AFM) data. These measurements show that step edges have little effect on the extent of adsorbed electroactive AQDS. Second, a new fast scan cyclic voltammetry (FSCV) protocol carried out with scanning electrochemical cell microscopy (SECCM) enables the evolution of AQDS adsorption to be followed locally on a rapid timescale. Subsequent AFM imaging of the areas probed by SECCM allows a direct correlation of the electroactive adsorption coverage and the actual step edge density of the entire working area. The amount of adsorbed electroactive AQDS and the electron transfer kinetics are independent of the step edge coverage. Last, SECCM reactive patterning is carried out with complementary AFM measurements, to probe the diffusional electroactivity of AQDS. There is essentially uniform and high activity across the basal surface of HOPG. This work provides new methodology to monitor adsorption processes at surfaces and shows unambiguously that there is no correlation between the step edge density of graphite surfaces and the observed coverage of electroactive AQDS. The electroactivity is dominated by the basal surface, and studies that have used AQDS as a marker of steps need to be revised.3

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Section: Introductionmentioning

confidence: 79%

Section: Impact Of Hopg Step Density On Adsorbed Electroactive Aqdsmentioning

confidence: 99%

Molecular Functionalization of Graphite Surfaces: Basal Plane versus Step Edge Electrochemical Activity

et al. 2014

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“…[45][46] Frederix et al 45 and Demaille et al, 46 setup, as the requirements for the tip are similar. [37][38][39][40][41] An elegant study using SECM-STM by Stimming et al 39 ( Figure 3) involved electrodepositing a single Pd NP on the tip and subsequently transferring it to a gold substrate.…”

Section: -44mentioning

confidence: 97%

In situ scanning electrochemical probe microscopy for energy applications

2012

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High resolution electrochemical imaging methods provide opportunities to study localized phenomena on electrode surfaces. Here, we review recent advances in scanning electrochemical microscopy (SECM) to study materials involved in (electrocatalytic) energy-related applications. In particular, we discuss SECM as a powerful screening technique and also advances in novel techniques based on micro-and nanopipets, such as the scanning micropipet contact method and scanning electrochemical cell microscopy and their use in energy-related research.

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“…6,24,25 Combined scanning electrochemical microscopy (SECM)-AFM, 26,27 likewise enables electroactivity to be directly and simultaneously related to substrate topography, with high spatial resolution. 28,29 It was found 28 that the basal surface of freshly cleaved HOPG was 'as active as template-stripped gold'…”

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confidence: 99%

Nanoscale Electrochemistry of sp² Carbon Materials: From Graphite and Graphene to Carbon Nanotubes

2016

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2 CONSPECTUSCarbon materials have a long history of use as electrodes in electrochemistry, from (bio)electroanalysis to applications in energy technologies, such as batteries and fuel cells. With the advent of new forms of nano-carbon, particularly carbon nanotubes and graphene, carbon electrode materials have taken on even greater significance for electrochemical studies, both in their own right, and as components and supports in an array of functional composites.With the increasing prominence of carbon nanomaterials in electrochemistry, comes a need to critically evaluate the experimental framework from which a microscopic understanding of electrochemical processes is best developed. This article advocates the use of emerging electrochemical imaging techniques and confined electrochemical cell formats that have considerable potential to reveal major new perspectives on the intrinsic electrochemical activity of carbon materials, with unprecedented detail and spatial resolution. These techniques allow particular features on a surface to be targeted and models of structure-activity to be developed and tested on a wide range of length scales and time scales.When high resolution electrochemical imaging data are combined with information from other microscopy and spectroscopy techniques applied to the same area of an electrode surface, in a correlative-electrochemical microscopy approach, highly resolved and unambiguous pictures of electrode activity are revealed that provide new views of the electrochemical properties of carbon materials. With a focus on major sp 2 carbon materials -graphite, graphene and single walled carbon nanotubes (SWNTs) -this article summarizes recent advances that have changed understanding of interfacial electrochemistry at carbon electrodes including:(i) Unequivocal evidence for the high activity of the basal surface of highly oriented pyrolytic graphite (HOPG), which is at least as active as noble metal electrodes (e.g. platinum) for outersphere redox processes. 3(ii) Demonstration of the high activity of basal plane HOPG towards other reactions, with no requirement for catalysis by step edges or defects, as exemplified by studies of proton-coupled electron transfer, redox transformations of adsorbed molecules, surface functionalization via diazonium electrochemistry and metal electrodeposition.(iii) Rationalization of the complex interplay of different factors that determine electrochemistry at graphene, including the source (mechanical exfoliation from graphite vs. graphene grown by chemical vapor deposition), number of graphene layers, edges, electronic structure, redox couple, and electrode history effects.(iv) New methodologies that allow nanoscale electrochemistry of 1D materials (SWNTs) to be related to their electronic characteristics (metallic vs. semiconductor SWNTs), size and quality, with high resolution imaging revealing the high activity of SWNT sidewalls and the importance of defects for some electrocatalytic reactions (e.g. the oxygen reduction reaction).The experimental ...

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Conductive supports for combined AFM–SECM on biological membranes

Cited by 60 publications

References 52 publications

Molecular Functionalization of Graphite Surfaces: Basal Plane versus Step Edge Electrochemical Activity

Molecular Functionalization of Graphite Surfaces: Basal Plane versus Step Edge Electrochemical Activity

In situ scanning electrochemical probe microscopy for energy applications

Nanoscale Electrochemistry of sp² Carbon Materials: From Graphite and Graphene to Carbon Nanotubes

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Conductive supports for combined AFM–SECM on biological membranes

Cited by 60 publications

References 52 publications

Molecular Functionalization of Graphite Surfaces: Basal Plane versus Step Edge Electrochemical Activity

Molecular Functionalization of Graphite Surfaces: Basal Plane versus Step Edge Electrochemical Activity

In situ scanning electrochemical probe microscopy for energy applications

Nanoscale Electrochemistry of sp2 Carbon Materials: From Graphite and Graphene to Carbon Nanotubes

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Product

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Nanoscale Electrochemistry of sp² Carbon Materials: From Graphite and Graphene to Carbon Nanotubes