Observation of microscopically local electron-transfer kinetics with scanning electrochemical microscopy

Engstrom, Royce C.; Small, Barbara.; Kattan, L.

doi:10.1021/ac00027a001

Cited by 42 publications

(23 citation statements)

References 27 publications

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“…The final cycle was stopped at 0.65 V/SCE for 30 s in order to partially oxidize the film. The platinum/ polypyrrole quasi-reference electrode was rinsed with acetone and soaked in pure acetonitrile for 1 h. After 30 min immersion in 1 M NaClO 4 , to exchange the PF 6 Ϫ counterion for ClO 4…”

Section: Methodsmentioning

confidence: 99%

Electrochemical Atomic Force Microscopy Using a Tip-Attached Redox Mediator for Topographic and Functional Imaging of Nanosystems

et al. 2009

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We describe the development of a new type of high-resolution atomic force electrochemical microscopy (AFM-SECM), labeled Tarm (for tip-attached redox mediator)/AFM-SECM, where the redox mediator, a ferrocene (Fc), is tethered to the AFM-SECM probe via nanometer long, flexible polyethylene glycol (PEG) chains. It is demonstrated that the tip-attached ferrocene-labeled PEG chains effectively shuttle electrons between the tip and substrate, thus acting as molecular sensors probing the local electrochemical reactivity of a planar substrate. Moreover the Fc-PEGylated AFM-SECM probes can be used for tapping mode imaging, allowing simultaneous recording of electrochemical feedback current and of topography, with a vertical and a lateral resolution in the nanometer range. By imaging the naturally nanostructured surface of HOPG, we demonstrate that Tarm/AFM-SECM microscopy can be used to probe the reactivity of nanometer-sized active sites on surfaces. This new type of SECM microscopy, being, by design, free of the diffusional constraints of classical SECM, is expected to, in principle, enable functional imaging of redox nanosystems such as individual redox enzyme molecules.

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Section: Methodsmentioning

confidence: 99%

Electrochemical Atomic Force Microscopy Using a Tip-Attached Redox Mediator for Topographic and Functional Imaging of Nanosystems

et al. 2009

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“…As early as 1992, Engstrom et al. used the special redox chemistry of the neurotransmitter epinephrine (E) 182. After oxidation at the sample, the initially formed quinone (EQ) reacts homogeneously to adenochrome (A), which can be reduced at more negative potentials than EQ.…”

Section: Secm As a Tool For Microstructuringmentioning

confidence: 99%

Scanning Electrochemical Microscopy for Direct Imaging of Reaction Rates

et al. 2007

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Not only in electrochemistry but also in biology and in membrane transport, localized processes at solid-liquid or liquid-liquid interfaces play an important role at defect sites, pores, or individual cells, but are difficult to characterize by integral investigation. Scanning electrochemical microscopy is suitable for such investigations. After two decades of development, this method is based on a solid theoretical foundation and a large number of demonstrated applications. It offers the possibility of directly imaging heterogeneous reaction rates and locally modifying substrates by electrochemically generated reagents. The applications range from classical electrochemical problems, such as the investigation of localized corrosion and electrocatalytic reactions in fuel cells, sensor surfaces, biochips, and microstructured analysis systems, to mass transport through synthetic membranes, skin and tissue, as well as intercellular communication processes. Moreover, processes can be studied that occur at liquid surfaces and liquid-liquid interfaces.

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“…[177] Mikropipetten, an deren Ende eine Flüssig-flüssig-Grenzfläche präpariert wurde, können für einen potentialgesteuerten Durchtritt von Metallionen genutzt werden, der sich zur Erzeugung diskontinuierlicher Metallstrukturen nutzen lässt. [178,179] [182] Nach Oxidation an der Probe setzt sich das zunächst gebildete Chinon (EQ) in einer Reaktion zu Adrenochrom (A) um, das bei negativeren Potentialen als EQ reduziert werden kann. Die UME wird nun so betrieben, dass sie EQ, aber nicht A, im GC-Modus reduzieren kann.…”

Section: Lokale Erzeugung Von Reaktantenunclassified

Elektrochemische Rastermikroskopie zur direkten Abbildung von Reaktionsgeschwindigkeiten

Wittstock¹,

Burchardt²,

Pust³

et al. 2007

Angewandte Chemie

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Eine entscheidende Rolle in der Elektrochemie, aber auch in biologischen Systemen oder beim Transport durch Membranen, spielen lokale Prozesse an Fest‐flüssig‐Grenzflächen oder Flüssig‐flüssig‐Grenzflächen, die z. B. an Defektstellen, an Poren oder an einzelnen Zellen ablaufen und sich durch integrale Untersuchungsverfahren nur schwer erfassen lassen. Mit der elektrochemischen Rastermikroskopie steht eine Untersuchungsmethode für lokale Grenzflächenreaktionen zur Verfügung, die nach zwei Jahrzehnten Entwicklung eine solide theoretische Basis und eine große Zahl von Anwendungen aufweist. Sie bietet die Möglichkeit, Geschwindigkeiten heterogener Reaktionen direkt abzubilden und Oberflächen durch elektrochemisch erzeugte Reaktanten lokal zu modifizieren. Die Vielfalt der Anwendungen reicht von klassischen elektrochemischen Fragestellungen bei der Untersuchung lokaler Korrosionsphänomene und elektrokatalytischer Reaktionen in Brennstoffzellen, von Sensoroberflächen, Biochips und mikrostrukturierten Analysesystemen bis hin zum Massentransport durch synthetische Membranen, Haut und Gewebe sowie interzellulären Kommunikationsprozessen. Außerdem können Prozesse an Flüssigkeitsoberflächen oder an Flüssig‐flüssig‐Grenzflächen untersucht werden.

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Observation of microscopically local electron-transfer kinetics with scanning electrochemical microscopy

Cited by 42 publications

References 27 publications

Electrochemical Atomic Force Microscopy Using a Tip-Attached Redox Mediator for Topographic and Functional Imaging of Nanosystems

Electrochemical Atomic Force Microscopy Using a Tip-Attached Redox Mediator for Topographic and Functional Imaging of Nanosystems

Scanning Electrochemical Microscopy for Direct Imaging of Reaction Rates

Elektrochemische Rastermikroskopie zur direkten Abbildung von Reaktionsgeschwindigkeiten

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