Deep eutectic solvents constitute a class of compounds sharing many similarities with properly named ionic liquids. The accepted deinition of ionic liquid is a luid liquid for T< °C) consisting of ions, while DES are eutectic mixtures of Lewis or "rønsted acids and bases. Their most atractive properties are the wide potential windows and the chemical properties largely diferent from aqueous solutions. In the last few decades, the possibility to electrodeposit decorative and functional coatings employing deep eutectic solvents as electrolytes has been widely investigated. " large number of the deposition procedures described in literature, however, cannot ind application in the industrial practice due to competition with existing processes, cost or diicult scalability. From one side, there is the real potential to replace existing plating protocols and to ind niche applications for high added-value productions to the other one, this paves the path towards the electrodeposition of metals and alloys thermodynamically impossible to be obtained via usual aqueous solution processes. The main aim of this chapter is therefore the critical discussion of the applicability of deep eutectic solvents to the electrodeposition of metals and alloys, with a particular atention to the industrial and applicative point of view.Keywords: electrodeposition, deep eutectic solvents, metals, alloys . IntroductionThe electrodeposition of metals for industrial surface inishing is nowadays a well-established industrial practice. Many processes are available to obtain a wide variety of coatings on most of © 2017 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.© 2017 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. the substrates used in manufacturing. There are however some important limitations, as not all the metal/substrate combinations are possible in the current state of the art. This is connected to the nature of the electrolytes used for the vast majority of the plating processes, which are water based. Water is the most obvious choice to formulate a plating electrolyte, and in the majority of the cases, it is also the most convenient from the point of view of the results obtained. This solvent however presents some limitations: narrow potential window, reactivity towards speciic metals, high hydrogen evolution in speciic conditions, etc. If metal plating is limited to aqueous solutions, many possibilities are therefore precluded." possible way to extend the range of coating/substrate combinations is the use of non-aqueous solvents, characterized by ext...

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In this work, a three-layered heterostructure Cu2O/CuO/CuS was obtained through a low-cost and large-area fabrication route comprising electrodeposition, thermal oxidation, and reactive annealing in a sulfur atmosphere. Morphological, microstructural, and compositional analysis (AFM, SEM, XRD, EDS, XPS) were carried out to highlight the surface modification of cuprous oxide film after oxidation and subsequent sulfurization. Impedance, voltammetric, and amperometric photoelectrochemical tests were performed on Cu2O, Cu2O/CuO, and Cu2O/CuO/CuS photocathodes in a sodium sulfate solution (pH 5), under 100 mW cm−2 AM 1.5 G illumination. A progressive improvement in terms of photocurrent and stability was observed after oxidation and sulfurization treatments, reaching a maximum of − 1.38 mA cm−2 at 0 V versus RHE for the CuS-modified Cu2O/CuO electrode, corresponding to a ~ 30% improvement. The feasibility of the proposed method was demonstrated through the fabrication of a large area photoelectrode of 10 cm2, showing no significant differences in characteristics if compared to a small area photoelectrode of 1 cm2.

The present work follows the trend to develop nonaqueous electrolytes for the deposition of corrosion resistant ZnNi alloys. It investigates the use of the choline chloride/ethylene glycol (1:2 molar ratio) eutectic mixture and of pure ethylene glycol as solvents for ZnNi electroplating. The electrochemical behavior of Zn and Ni is investigated via cyclic voltammetry, and potentiostatic ZnNi deposition is performed. Ni content is found to be precisely tunable in the 10−20% wt range, which presents the highest industrial interest for corrosion protection. ZnNi coatings obtained are characterized from the morphological and phase composition point of view. Evidence of the formation of a metastable γ ZnNi phase is observed for both choline chloride/ ethylene glycol and pure ethylene glycol. Finally, potentiodynamic corrosion tests are performed to assess their corrosion properties.