Nanoparticle-Mediated Electron Transfer Across Ultrathin Self-Assembled Films

Zhao, Jianjun; Bradbury, Christopher R.; Huclova, Sonja; Potapova, Inga; Carrara, Michel; Fermı́n, David J.

doi:10.1021/jp054127s

Cited by 111 publications

(186 citation statements)

References 57 publications

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“…As soon as nanoparticles complete the assembly depicted in Figure 4A, however, fully reversible behaviour is restored, Figure 4B, trace c, in support of reported results [25][26][27][28][29]. The reversibility of the Au/MUA/ PLY/AuNP electrode response is further asserted by the fact that the peak-to-peak separation remained identical to the value for the bare electrode for scan rates up to 200 mV s…”

Section: Stationary Electrode Responsesupporting

confidence: 87%

“…We consider next the electrostatic strategy [25][26][27][28] in which an ultrathin polycation (here, poly-l-lysine (PLY)) layer is assembled atop an w-mercaptoacid (here, 11-mercaptoundecanoic acid (MUA)) SAM. The resulting positively charged surface termination can then accommodate negatively charged species such as the nanoparticles in focus, leading to an assembly as shown schematically in Figure 4A.…”

Section: Electrode Build-upmentioning

confidence: 99%

“…In a recent series of papers, the Fermín group demonstrated efficient electronic communication for polyelectrolyte-based layer-by-layer assemblies [25][26][27][28]. A remarkable finding was that the kinetics of such nanostructured electrodes remains fast and independent of the SAM thickness over a large range, whereas generally under conditions where non-resonant tunnelling prevails an exponential distance dependence is observed [29].…”

Section: Introductionmentioning

confidence: 99%

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Covalent versus Electrostatic Strategies for Nanoparticle Immobilisation

et al. 2010

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We demonstrate that in neutral electrolytes, a polyelectrolyte-based (w-mercaptoacid/poly-l-lysine) immobilisation strategy for as-prepared electrostatically stabilised metal nanoparticles is a powerful alternative to often difficult to control dithiol approaches. Our data confirm straightforward preparation of high-coverage nanoparticle electrodes with fast kinetics and an electrochemical window of up to 1.5 V even in unbuffered solutions, under both stationary and hydrodynamic conditions. The stability region is limited by reductive desorption of the mercaptocarboxylic acid at negative potentials, and by nanoparticle oxidation at positive potentials. The electrostatic immobilisation is valuable for the study of electroanalytical and electrocatalytic processes using nanoparticulate electrode materials.

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Section: Stationary Electrode Responsesupporting

confidence: 87%

Section: Electrode Build-upmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Covalent versus Electrostatic Strategies for Nanoparticle Immobilisation

et al. 2010

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“…Electron transfer between the electrode and NP was reasonably assumed to occur when the NP was within 1 nm of the electrode. 28 We performed 200 simulations each of 3 ms duration with the NP having the same initial position at the start (5 nm above the electrode, over the center). As the NP moved from the start position and began to encounter the electrode, the simulations showed a distribution of rise times, defined as the time taken for the occupancy to change from an average of 0.1 to 0.9, centered around 465 s, as summarized in Figure 4A.…”

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confidence: 99%

Time-Resolved Detection and Analysis of Single Nanoparticle Electrocatalytic Impacts

et al. 2015

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ABSTRACT:There is considerable interest in understanding the interaction and activity of single entities, such as (electro)catalytic nanoparticles (NPs), with (electrode) surfaces. Through the use of a high bandwidth, high signal/noise measurement system, NP impacts on an electrode surface are detected and analyzed in unprecedented detail, revealing considerable new mechanistic information on the process. Taking the electrocatalytic oxidation of H2O2 at ruthenium oxide (RuOx) NPs as an example, the rise time of currenttime transients for NP impacts is consistent with a hydrodynamic trapping model for the arrival of a NP with a distancedependent NP diffusion-coefficient. NP release from the electrode appears to be aided by propulsion from the electrocatalytic reaction at the NP. High frequency NP impacts, orders of magnitude larger than can be accounted for by a single pass diffusive flux of NPs, are observed that indicate the repetitive trapping and release of an individual NP that has not previously recognized. The experiments and models described could readily be applied to other systems and serve as a powerful platform for detailed analysis of NP impacts.An important frontier in electrochemistry is measuring the behavior of individual nano-entities such as nanoparticles (NPs), nanowires and nanorods and relating this to other properties such as size, structure and electronic characteristics, so as to develop fundamental understanding and rational applications. 1-3 An interesting approach for observing the electrochemical properties of catalytic NPs is to monitor their impact (or landing) from solution onto a collector electrode, as introduced by Bard et al.,4,5 and developed by several groups. [6][7][8][9][10][11][12] In order to resolve such impacts, the use of a small-sized ultramicroelectrode (UME) is mandatory to reduce both background currents and the impact frequency. To enhance the impact signal to background current, electrode surfaces have been modified with Hg or Bi 7 and borondoped diamond 12 has also been used as an UME material. Alternatively, scanning electrochemical cell microscopy (SECCM) functioning as an ultramicro-electrochemical cell system offers particularly low background currents by reducing the area of the collector electrode, as well as offering the widest range of support electrodes. This is because the electrochemical cell is formed by meniscus confinement, rather than electrode encapsulation (Figure 1). 13 Despite these innovations, detailed analysis of the form of the current-time profile which is the primary signal for the landing (and detachment) of a single NP on an electrode has not yet been forthcoming, but would represent a huge advance towards understanding the impact process. Herein, we are able to analyze this process as never before and deduce key information on the NP arrival and release process from individual impact transients. Moreover, we show that impact frequencies can be orders of magnitude higher than expected based on single pass diffusion due to the repetitiv...

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“…[13] In a very elegant series of papers, Fermin and co-workers explored the electrochemistry of electrode-SAM-NP assemblies in considerable detail. [8,[16][17][18] The construct employed involved an alkanethiol modified gold electrode, where the alkanethiol possessed a carboxylic acid at its distal end. To bind gold nanoparticles to this surface, a poly-l-lysine was adsorbed onto the SAM, with the amines of this weak polyelectrolyte serving as coupling points to which gold nanoparticles were bound.…”

mentioning

confidence: 99%

Some More Observations on the Unique Electrochemical Properties of Electrode–Monolayer–Nanoparticle Constructs

et al. 2010

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Physical and electrochemical properties of gold nanoparticle-based electrodes are highlighted. Polycrystalline gold electrodes are passivated by a self-assembled monolayer, then the immobilization of gold nanoparticles "switch on" the electrochemical reactivity of ruthenium. Herein, gap-mode Raman studies show that the location of the nanoparticles is on the top of the monolayer, meaning that the "switching on" cannot be attributed to a direct electrical contact between nanoparticles and the gold support. This "switching on" feature is also not affected by the size of the gold nanoparticles with a range of diameters between 4 and 67 nm. Further, the charge of the nanoparticles is investigated by grafting chemical groups onto the nanoparticles which is observed to alter the electron-transfer kinetics. The variation in rate constant however is insufficient to attribute the "switching on" phenomenon to a possible adsorption of the redox species onto the nanoparticles.

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Nanoparticle-Mediated Electron Transfer Across Ultrathin Self-Assembled Films

Cited by 111 publications

References 57 publications

Covalent versus Electrostatic Strategies for Nanoparticle Immobilisation

Covalent versus Electrostatic Strategies for Nanoparticle Immobilisation

Time-Resolved Detection and Analysis of Single Nanoparticle Electrocatalytic Impacts

Some More Observations on the Unique Electrochemical Properties of Electrode–Monolayer–Nanoparticle Constructs

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