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Recent Advances in Voltammetry.

Batchelor-McAuley C, Kätelhön E, Barnes EO, Compton RG, Laborda E, Molina A - ChemistryOpen (2015)

Bottom Line: The transformation over the last decade of the level of modelling and simulation of experiments has realised major advances such that electrochemical techniques can be fully developed and applied to real chemical problems of distinct complexity.This review focuses on the topic areas of: multistep electrochemical processes, voltammetry in ionic liquids, the development and interpretation of theories of electron transfer (Butler-Volmer and Marcus-Hush), advances in voltammetric pulse techniques, stochastic random walk models of diffusion, the influence of migration under conditions of low support, voltammetry at rough and porous electrodes, and nanoparticle electrochemistry.The review of the latter field encompasses both the study of nanoparticle-modified electrodes, including stripping voltammetry and the new technique of 'nano-impacts'.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford South Parks Road, Oxford, OX1 3QZ, UK.

ABSTRACT
Recent progress in the theory and practice of voltammetry is surveyed and evaluated. The transformation over the last decade of the level of modelling and simulation of experiments has realised major advances such that electrochemical techniques can be fully developed and applied to real chemical problems of distinct complexity. This review focuses on the topic areas of: multistep electrochemical processes, voltammetry in ionic liquids, the development and interpretation of theories of electron transfer (Butler-Volmer and Marcus-Hush), advances in voltammetric pulse techniques, stochastic random walk models of diffusion, the influence of migration under conditions of low support, voltammetry at rough and porous electrodes, and nanoparticle electrochemistry. The review of the latter field encompasses both the study of nanoparticle-modified electrodes, including stripping voltammetry and the new technique of 'nano-impacts'.

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Anodic stripping voltammetry for small (rnp=3.7 nm, dashed line) and large (rnp=13.5 nm, solid line) silver nanoparticles supported on a micro carbon-fibre electrode (r0=5.5 μm): A) low surface coverage of silver (1.6×105 mol m−2) and B) high surface coverage (1.6×104 mol m−2). Scan rate: 50 mV s−1 and supporting electrolyte of 0.1 m NaClO4. Reproduced with permission from Ref. 164. Copyright 2014, Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.
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fig28: Anodic stripping voltammetry for small (rnp=3.7 nm, dashed line) and large (rnp=13.5 nm, solid line) silver nanoparticles supported on a micro carbon-fibre electrode (r0=5.5 μm): A) low surface coverage of silver (1.6×105 mol m−2) and B) high surface coverage (1.6×104 mol m−2). Scan rate: 50 mV s−1 and supporting electrolyte of 0.1 m NaClO4. Reproduced with permission from Ref. 164. Copyright 2014, Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Mentions: Figure 28 depicts the stripping voltammetry for two sizes of nanoparticles at two different surface coverages from a carbon-fibre microelectrode (r0=5.5 μm), where the observed shift is consistent with a change in the thermodynamics due to the influence of the altered surface energy. Note that the observed peak potential also varies in both cases as a function of the total surface coverage of silver. Not all nanoparticle redox reactions result in the dissolution of the nanoparticle (though there will be a corresponding change in the nanoparticle morphology). One example of such a case is the oxidation of silver in the presence of a halide. Depending on the halide concentration, the electrochemical oxidation will likely lead to the formation of surface bound silver halide.165 A secondary example would be the electrochemical formation of metal oxides.166 The voltammetric response of such systems is highly complicated; first and foremost, the formation (or solubility) constant between the formed nanoparticle ion and the solution-phase counter-ion serves to alter the thermodynamics of the redox species in accordance with the Nernst equation.167 Second, the reduction or oxidation may exhibit complex behaviour such as following a nucleation growth mechanism.168 Third, speciation of the products may vary as a function of counter-ion concentration.169 Finally, in some cases the reaction may be limited by the mass transport of the counter-ion to the electrochemical interface. Consequently, again when studying these systems, care must be taken when ascribing any alteration in the stripping peak potentials as relating to altered thermodynamics or ‘nano-effects.’ This is especially true due to the fact that the nanoparticle capping agents have been shown to influence the observed stripping voltammetry.161 As an interesting aside, the strength of the binding of silver ions to halides and the corresponding Nernstian shift in the stripping peak yield an analytically useful route to their detection via the use of nanoparticle stripping voltammetry.167


Recent Advances in Voltammetry.

Batchelor-McAuley C, Kätelhön E, Barnes EO, Compton RG, Laborda E, Molina A - ChemistryOpen (2015)

Anodic stripping voltammetry for small (rnp=3.7 nm, dashed line) and large (rnp=13.5 nm, solid line) silver nanoparticles supported on a micro carbon-fibre electrode (r0=5.5 μm): A) low surface coverage of silver (1.6×105 mol m−2) and B) high surface coverage (1.6×104 mol m−2). Scan rate: 50 mV s−1 and supporting electrolyte of 0.1 m NaClO4. Reproduced with permission from Ref. 164. Copyright 2014, Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4522172&req=5

fig28: Anodic stripping voltammetry for small (rnp=3.7 nm, dashed line) and large (rnp=13.5 nm, solid line) silver nanoparticles supported on a micro carbon-fibre electrode (r0=5.5 μm): A) low surface coverage of silver (1.6×105 mol m−2) and B) high surface coverage (1.6×104 mol m−2). Scan rate: 50 mV s−1 and supporting electrolyte of 0.1 m NaClO4. Reproduced with permission from Ref. 164. Copyright 2014, Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.
Mentions: Figure 28 depicts the stripping voltammetry for two sizes of nanoparticles at two different surface coverages from a carbon-fibre microelectrode (r0=5.5 μm), where the observed shift is consistent with a change in the thermodynamics due to the influence of the altered surface energy. Note that the observed peak potential also varies in both cases as a function of the total surface coverage of silver. Not all nanoparticle redox reactions result in the dissolution of the nanoparticle (though there will be a corresponding change in the nanoparticle morphology). One example of such a case is the oxidation of silver in the presence of a halide. Depending on the halide concentration, the electrochemical oxidation will likely lead to the formation of surface bound silver halide.165 A secondary example would be the electrochemical formation of metal oxides.166 The voltammetric response of such systems is highly complicated; first and foremost, the formation (or solubility) constant between the formed nanoparticle ion and the solution-phase counter-ion serves to alter the thermodynamics of the redox species in accordance with the Nernst equation.167 Second, the reduction or oxidation may exhibit complex behaviour such as following a nucleation growth mechanism.168 Third, speciation of the products may vary as a function of counter-ion concentration.169 Finally, in some cases the reaction may be limited by the mass transport of the counter-ion to the electrochemical interface. Consequently, again when studying these systems, care must be taken when ascribing any alteration in the stripping peak potentials as relating to altered thermodynamics or ‘nano-effects.’ This is especially true due to the fact that the nanoparticle capping agents have been shown to influence the observed stripping voltammetry.161 As an interesting aside, the strength of the binding of silver ions to halides and the corresponding Nernstian shift in the stripping peak yield an analytically useful route to their detection via the use of nanoparticle stripping voltammetry.167

Bottom Line: The transformation over the last decade of the level of modelling and simulation of experiments has realised major advances such that electrochemical techniques can be fully developed and applied to real chemical problems of distinct complexity.This review focuses on the topic areas of: multistep electrochemical processes, voltammetry in ionic liquids, the development and interpretation of theories of electron transfer (Butler-Volmer and Marcus-Hush), advances in voltammetric pulse techniques, stochastic random walk models of diffusion, the influence of migration under conditions of low support, voltammetry at rough and porous electrodes, and nanoparticle electrochemistry.The review of the latter field encompasses both the study of nanoparticle-modified electrodes, including stripping voltammetry and the new technique of 'nano-impacts'.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford South Parks Road, Oxford, OX1 3QZ, UK.

ABSTRACT
Recent progress in the theory and practice of voltammetry is surveyed and evaluated. The transformation over the last decade of the level of modelling and simulation of experiments has realised major advances such that electrochemical techniques can be fully developed and applied to real chemical problems of distinct complexity. This review focuses on the topic areas of: multistep electrochemical processes, voltammetry in ionic liquids, the development and interpretation of theories of electron transfer (Butler-Volmer and Marcus-Hush), advances in voltammetric pulse techniques, stochastic random walk models of diffusion, the influence of migration under conditions of low support, voltammetry at rough and porous electrodes, and nanoparticle electrochemistry. The review of the latter field encompasses both the study of nanoparticle-modified electrodes, including stripping voltammetry and the new technique of 'nano-impacts'.

No MeSH data available.


Related in: MedlinePlus