1,721,035 research outputs found
A First Course in Electrode Processes, Chinese Edition
No full textThis user friendly introduction highlights the importance of electrochemistry and its applications to the modern world and the future. In contrast to other texts currently available, it emphasises understanding and avoids using many pages of complex equations. It also describes the diverse applications of electrochemistry rather than focusing on analytical chemistry alone. Although the book follows a similar structure to the first edition, the earlier chapters have been extensively up-dated and the later chapters are entirely new. The text is supported by a large number of figures which illustrate key points. The book starts by describing the essential electrochemical techniques before moving on to cover experimental problems and applications. To reflect the present interest in fuel cells and the environment, these have become the focus of the final chapters. A useful appendix contains problems with fully worked answers to test the reader's understandin
The cathodic reduction of carbon dioxide—what can it realistically achieve? A mini review
Full text linkThere is a very large literature and continued interest in the electrochemical reduction of carbon dioxide. The reasons for the continued study of this reaction are reviewed. Suggestions that the electrolytic reduction of carbon dioxide can be used to reduce the level of this greenhouse gas in the atmosphere are shown to be wishful thinking. Also, using this reaction as part of a cycle for large-scale energy storage is not a promising technology. More realistic goals are using CO2 as a cheap source of carbon in electrosynthesis and the development of sensors for CO2. The reduction of CO2 is also important from a fundamental viewpoint. Many different products have been confirmed depending on the electrolysis conditions (particularly electrode material and electrolyte medium), and understanding this variation would be a major boost to our understanding of electrode reactions in general. The reduction of CO2 is also an ideal model reaction for developing approaches to increasing the current density for large-scale electrolysis with gaseous reactants
A first course in electrode processes
No full textThis user friendly introduction highlights the importance of electrochemistry and its applications to the modern world and the future. In contrast to other texts currently available, it emphasises understanding and avoids using many pages of complex equations. It also describes the diverse applications of electrochemistry rather than focusing on analytical chemistry alone.Although the book follows a similar structure to the first edition, the earlier chapters have been extensively up-dated and the later chapters are entirely new. The text is supported by a large number of figures which illustrate key points.The book starts by describing the essential electrochemical techniques before moving on to cover experimental problems and applications. To reflect the present interest in fuel cells and the environment, these have become the focus of the final chapters.A useful appendix contains problems with fully worked answers to test the reader's understanding
Organic electrosynthesis – A road to greater application. A mini review
No full textDespite a long history, electrosynthesis has never become a routine procedure in organic synthesis laboratories or for the manufacture of organic compounds within industry. One major reason is the nature of the literature. This review highlights the need for electrosyntheses to meet the demands of the user and for papers to make this clear. To be attractive to synthetic chemists, papers need to demonstrate a high conversion of reactant to product as well as the isolation of pure product on a scale of interest and in high yield. In addition, it is absolutely essential that papers include a detailed description of the procedure, especially the electrolysis cell (geometry, dimensions, component materials and sources, mass transfer regime etc.) and all the control parameters (solvent, concentration of reactants(s) and electrolyte, pH, cell current, temperature etc.) used for the electrolysis.</p
The influence of deposition conditions and dopant ions on the structure, activity, and stability of lead dioxide anode coatings
No full textbeta-lead dioxide layers have been electroplated onto gold from nitric acid solutions and the influence of lead (II) concentration, dopant ions in the bath, pH, temperature, current density, and deposition time on the characteristics of the deposits and their properties as anode materials for synthesis and effluent treatment have been examined. The most adhesive, abrasion resistant and chemically stable deposits were prepared in 0.5 M Pb(NO3)(2)/1 M HNO3 at a temperature of 333 K and using a current density of 5 mA cm(-2); these deposits had a morphology consisting of angular crystallites but they were rather inactive as anode materials. In many other conditions, deposits were made up of overlapping hemispherical centers. Such layers were significantly less stable in open-circuit conditions and were both dissolved slowly in acids and reduced by dimethyl sulfoxide in acidic solutions. On the other hand, they supported the anodic oxidation of organic molecules. Bismuth (III) was a preferred dopant ions; it led to a preference for deposits consisting of hemispherical centers even in conditions where angular crystallites were formed in the absence of Bi (III). The Bi (III) doped coatings represent the best compromise between stability and the ability to support anodic oxidations
A novel flow battery: a lead acid battery based on an electrolyte with soluble lead(II). Part III: the influence of conditions on battery performance
No full textThe performance of an undivided flow battery based on the Pb(II)/Pb and PbO2/Pb(II) couples in aqueous methanesulfonic acid as a function of state of charge, current density, electrolyte flow rate and temperature is reported. In addition, it is demonstrated that the cell chemistry can be rebalanced after multiple charge/discharge by allowing the excess lead metal deposited at the negative electrode to react with oxygen on open circuit
A novel flow battery: A lead acid battery based on an electrolyte with soluble lead(II). Part II. Flow cell studies
No full textThe design and performance of a small redox flow battery is described; it is based on a single undivided, parallel plate cell with carbon electrodes and an acidic lead methanesulfonate electrolyte. It is shown that the cell operates as a secondary battery at charge/discharge current densities of 10–60 mA cm–2. Typically, the voltage during discharge is 1.55 V, Coulombic efficiency >85% and the energy efficiency 65%
The electrodeposition and electrocatalytic properties of copper-palladium alloys
No full textThe codeposition of copper and palladium from solutions of CuSO4 and PdSO4 in 0.6 M HClO4 is investigated using microdisc voltammetry. It is shown that good quality coatings of CuPd may be deposited and the composition may be controlled either through the deposition potential or the Cu(II)/Pd(II) ratio in solution. While the deposits seem to be amorphous and the copper can be dissolved anodically, the voltammetry indicates that the palladium stabilises the copper to dissolution. The CuPd alloys are effective catalysts for nitrate reduction in alkaline media
The fabrication of lead dioxide layers on a titanium substrate
No full textIt is shown that stable and active lead dioxide on titanium anodes (including mesh electrodes) may be fabricated by appropriate pretreatment of the substrate and a strategy involving the anodic deposition of two PbO2 layers-a thick underlayer with the lead dioxide doped with fluoride and iron and a top layer with the lead dioxide doped with bismuth. Periods on open circuit, especially in solutions containing an oxidisable organic or inorganic species must, however, be avoided since all forms of PbO2 are reducible unless protected by an anodic current; the rates of the reduction does depend on the medium, the dopants in the PbO2 and the morphology of the layer. It is also shown that, as at gold substrates, the morphology of the PbO2 layer on titanium (consequently, their properties including adhesion and electrocatalytic activity) depend strongly on the deposition conditions including the bath composition (including Pb(II) concentration, acid concentration, concentration and choice of dopantion), temperature, current density and deposition charge
The synthesis of diaryliodonium salts by the anodic oxidation of aryl iodide/arene mixtures
No full textThe syntheses of diaryliodonium salts by the anodic oxidation of an aryl iodide in the presence of an arene in solvents containing acetic acid, acetic anhydride, and an acid are investigated. The influence of the reaction conditions on the yield of the 4,4'-dimethyldiphenyliodonium cation from the electrolysis of solutions containing both 4-iodotoluene and toluene is explored. The reaction gives good yields of diaryliodonium salts for aryl iodides and arenes with alkyl substituents. The factors that limit the extension of the reaction to other functional groups are discussed
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