Refine
Document Type
- Article (6)
Language
- English (6)
Has Fulltext
- yes (6)
Is part of the Bibliography
- no (6)
Keywords
- Basic concepts (1)
- Cobalt (1)
- Education (1)
- Electroanalysis (1)
- Electrochemistry (1)
- Electrodes of second kind (1)
- Ethics (1)
- Gibbs energy (1)
- Hysteresis (1)
- Interfaces (1)
- Ion insertion (1)
- Ion-sensitive electrodes (ISE) (1)
- Journal (1)
- Kinetics (1)
- Measuring techniques (1)
- Nickel (1)
- Peer review (1)
- Phase transition (1)
- Potentiometry (1)
- Publishing (1)
- Science (1)
- Thermodynamics (1)
- corrosion (1)
- dissolution mechanism (1)
- electron transfer (1)
- gold dissolution (1)
- in situ-ICP-MS (1)
- manganese oxide (1)
- proton insertion (1)
- standard potential (1)
- surface state (1)
Institute
Publisher
- Springer Nature (3)
- Wiley (3)
Abstract
This work presents the reactivity and dissolution of an as‐polished and electrochemically pre‐treated polycrystalline Au electrode, which is used as a model system. The effect of the electrochemical pre‐treatment in corrosive 0.37 M HCl solutions on the Au surface roughness and dissolution is investigated by varying the number of pre‐treatment steps at 1.16 V against the reversible hydrogen electrode. It is shown that the first 10 s pre‐treatment of the as‐polished Au results in a higher surface roughness and thus higher electrochemically active surface area (ECSA) than that of the as‐polished Au. With the subsequent pre‐treatments, however, the ECSA is gradually decreasing reaching a steady value. The dissolution rate of the pre‐treated Au electrodes upon potential cycling in 0.1 M H2SO4 is determined by in situ inductively coupled plasma mass spectrometry. A non‐linear dependence of Au dissolution amount is found with respect to the number of pre‐treatments. The overall total Au dissolution rate follows a similar trend as ECSA/roughness. However, an important difference in the dissolution behavior is identified with respect to dissolution processes during Au oxidation (anodic dissolution) and Au reduction (cathodic dissolution): the former is more sensitive to the surface roughness. Thus, the ratio between Au anodic and cathodic dissolution amounts decreases substantially with decrease in surface roughness. This finding is explained by the slow and fast dissolution kinetics for anodic and cathodic processes, respectively. Current work further advances our understanding of the complex Au dissolution mechanism.
Electrochemically active ϵ‐MnO2 and ɣ‐MnO2 as tunnel‐type host‐guest structures have been extensively studied by crystallography and electrochemical techniques for application in battery cathode materials. However, the Gibbs energies of the underlying ion and electron transfer processes across the electrode interfaces have not yet been determined. Here we report for the first time these data for ϵ‐MnO2. This was possible by measuring the mid‐peak potentials in cyclic voltammetry and the open‐circuit potentials under electrochemically reversible conditions.
This text is designed to give the reader a helping hand in writing a scientific paper. It provides generic advice on ways that a scientific paper can be improved. The focus is on the following ethical and non-technical issues: (1) when to start writing, and in what language; (2) how to choose a good title; (3) what should be included in the various sections (abstract, introduction, experimental, results, discussion, conclusions, and supporting information (supplementary material); (4) who should be considered as a co-author, and who should be acknowledged for help; (5) which journal should be chosen; and (6) how to respond to reviewers’ comments. Purely technical issues, such as grammar, artwork, reference styles, etc., are not considered.
The potential of several ion-sensitive electrodes responds to the incorporated cations and anions. This has led some authors to misinterpret the potential of metal salt membrane electrodes and of electrodes of the second kind. Neglecting the kinetics of potential establishment and interpreting the potentials solely based on thermodynamics produce completely irrelevant data and suggest that ion concentrations down to 10−45 mol L−1 are accessible by simple potentiometric measurements. The switching from cation to anion response mechanism cannot be derived from thermodynamic equations. It bears complete similarity to the switching of response in the case of foreign interfering ions.
In teaching electrochemistry, it is of primary importance to make students always aware of the relations between electrochemistry and all the non-electrochemical topics, which are taught. The vast majority of students will not specialise in electrochemistry, but they all can very much benefit from the basics and concepts of electrochemistry. This paper is aimed to give suggestions how the teaching of electrochemistry can easily be interrelated to topics of inorganic, organic, analytical, environmental chemistry, biochemistry and biotechnology.
The transition to Ni‐based battery cathodes enhances the energy density and reduces the cost of batteries. However, this comes at the expense of losing energy efficiency which could be a consequence of charge–discharge hysteresis. Here, a thermodynamic model is developed to understand the extent and origin of charge–discharge hysteresis in battery cathodes based on their cyclic voltammograms (CVs). This was possible by defining a Gibbs energy function that weights random ion insertion/expulsion, i. e., a solid solution pathway, against selective ion insertion/expulsion, i. e., a phase separation route. The model was verified experimentally by the CVs of CoOOH and Ni(OH)2 as solid‐solution and phase‐separating cathodes, respectively. Finally, a microscopic view reveals that phase separation and hysteresis are a consequence of large ionic radii difference of the reduced and oxidized central metal atoms.