Electrochemistry of Nanoparticles

Kleijn, Steven; Lai, Stanley C. S.; Koper, Marc T. M.; Unwin, Patrick R.

doi:10.1002/anie.201306828

Cited by 359 publications

(331 citation statements)

References 366 publications

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“…However, such organic molecules, which surround the nanoparticle, are likely to decrease the electrocatalytic activity of the nanoparticle. 6 Therefore, to observe the unique electrocatalytic activity of the metal nanoparticle, the organic molecules including the stabilizing agent or additive, which surround the nanoparticle should be removed after depositing the metal nanoparticle on the electrode surface. To obtain a clean metal electrode surface, a suggestive general method is to repetitively cycle the potential in acidic condition, thereby removing the organic material from the surface of the nanoparticles constituting the electrode.…”

Section: 3mentioning

confidence: 99%

Effect of Electrochemical Oxidation-Reduction Cycles on Surface Structures and Electrocatalytic Oxygen Reduction Activity of Au Electrodes

Lim¹,

Kim²

2016

Journal of the Korean Chemical Society

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ABSTRACT. Oxidation-reduction cycling (ORC) procedures are widely used for cleaning nanoparticle surfaces when investigating their electrocatalytic activities. In this work, the effect of ORC on the surface structures and electrocatalytic oxygen reduction activity of Au electrodes is analyzed. Different structural changes and variations in electrocatalysis are observed depending on the initial structure of the Au electrodes, such as flat bulk, nanoporous, nanoplate, or dendritic Au. In particular, dendritic Au structures lost their sharp-edge morphology during the ORC process, resulting in a significant decrease in its electrocatalytic oxygen reduction activity. The results shown in this paper provide an insight into the pretreatment of nanoparticle-based electrodes during investigation of their electrocatalytic activities.

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Section: 3mentioning

confidence: 99%

Effect of Electrochemical Oxidation-Reduction Cycles on Surface Structures and Electrocatalytic Oxygen Reduction Activity of Au Electrodes

Lim¹,

Kim²

2016

Journal of the Korean Chemical Society

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“…The electrochemical behaviour of metallic nanoparticles has received significant attention due to their applicability as electrocatalysts for a variety of technologically important reactions, in particular, related to fuel cells and electrochemical sensing [1][2][3][4][5][6][7]. There are numerous approaches to creating nanoparticles; however, chemical synthesis is particularly attractive given the high degree of control that can be achieved over their size, shape and monodispersity [8].…”

Section: Introductionmentioning

confidence: 99%

“…However, there are other factors that need to be considered when assessing the applicability of an electrocatalyst and that is the presence of defect sites and capping agents. In general, it is agreed that the removal of stabilising species from the surface of nanoparticles is required to ensure access to surface active sites that are responsible for electrocatalytic activity [2]. In many cases, this can be quite involved and may perturb the shape and size of the nanomaterial in question.…”

Section: Introductionmentioning

confidence: 99%

Probing the surface oxidation of chemically synthesised gold nanospheres and nanorods

2014

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In this study, the electrochemical behaviour of commercially available gold spheres and rods stabilised by carboxylic acid and cetyl trimethyl ammonium bromide (CTAB) moieties, respectively, are investigated. The cyclic voltammetric behaviour in acidic electrolyte is distinctly different with the nanorods exhibiting unusual oxidative behaviour due to an electrodissolution process. The nanospheres exhibited responses typical of a highly defective surface which significantly impacted on electrocatalytic activity. A repetitive potential cycling cleaning procedure was also investigated which did not improve the activity of the nanorods and resulted in deactivating the gold spheres due to decreasing the level of surface defects.

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“…This is particularly true in the area of heterogeneous catalysis (1)(2)(3)(4)(5)(6)(7)(8)(9)(10). The advantages of ensembles of nanoparticles over foils of the same catalytic material, as well as the role of the particle size, have been frequently recognized with regard to rates.…”

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confidence: 99%

Catalysis at the nanoscale may change selectivity

Costentin

Savéant

2016

Proc. Natl. Acad. Sci. U.S.A.

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Among the many virtues ascribed to catalytic nanoparticles, the prospect that the passage from the macro-to the nanoscale may change product selectivity attracts increasing attention. To date, why such effects may exist lacks explanation. Guided by recent experimental reports, we propose that the effects may result from the coupling between the chemical steps in which the reactant, intermediates, and products are involved and transport of these species toward the catalytic surface. Considering as a thought experiment the competitive formation of hydrogen and formate upon reduction of hydrogenocarbonate ions on metals like palladium or platinum, a model is developed that allows one to identify the governing parameters and predict the effect of nanoscaling on selectivity. The model leads to a master equation relating product selectivity and thickness of the diffusion layer. The latter parameter varies considerably upon passing from the macro-to the nanoscale, thus predicting considerable variations of product selectivity. These are subtle effects in the sense that the same mechanism might exhibit a reverse variation of the selectivity if the set of parameter values were different. An expression is given that allows one to predict the direction of the effect. There has been a tendency to assign the catalytic effects of nanoscaling to chemical reactivity changes of the active surface. Such factors might be important in some circumstances. We, however, insist on the likely role of short-distance transport on product selectivity, which could have been thought, at first sight, as the exclusive domain of chemical factors.energy | nanoparticles | electrocatalysis N anoparticles work wonders in many fields of science and technology. This is particularly true in the area of heterogeneous catalysis (1-10). The advantages of ensembles of nanoparticles over foils of the same catalytic material, as well as the role of the particle size, have been frequently recognized with regard to rates. The answer is more elusive as to the possible effect of nanoscaling on product selectivity. It is tempting to attribute such effects to the creation of surface defects that may be triggered by the deposition of the nanoparticles. We, however, explore another type of rationale.The systems where some relevant information is available are few but concern important processes in the area of contemporary energy challenges (11)(12)(13)(14), namely the electrochemical hydridation of CO 2 into HCO 2 − versus H 2 evolution at a metal electrode in aqueous media (15)(16)(17)(18)(19). This is the case when the metal is palladium with which little formate, if any, is generated upon electrolysis on a Pd foil (18,20), whereas the formate faradaic yield reaches 90-95% with ∼5-nm-diameter Pd nanoparticles dispersed on ∼100-nm carbon particles (18). Very high faradaic yields of formate are similarly found on carbon supported Pt-Pd nanoparticle electrodes in a pH 6.7 phosphate buffer (21,22).How can such major differences in product selectivity be explained whe...

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Electrochemistry of Nanoparticles

Cited by 359 publications

References 366 publications

Effect of Electrochemical Oxidation-Reduction Cycles on Surface Structures and Electrocatalytic Oxygen Reduction Activity of Au Electrodes

Effect of Electrochemical Oxidation-Reduction Cycles on Surface Structures and Electrocatalytic Oxygen Reduction Activity of Au Electrodes

Probing the surface oxidation of chemically synthesised gold nanospheres and nanorods

Catalysis at the nanoscale may change selectivity

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