Electrodeposition behavior and characterization of copper–zinc alloy in deep eutectic solvent

Speciation of Copper(II)-Betaine Complexes as Starting Point for Electrochemical Copper Deposition from Ionic Liquids

The application of ionic liquids for the dissolution of metal oxides is a promising field for the development of more energy- and resource-efficient metallurgical processes. Using such solutions for the production of valuable chemicals or electrochemical metal deposition requires a detailed understanding of the chemical system and the factors influencing it. In the present work, several compounds are reported that crystallize after the dissolution of copper(II) oxide in the ionic liquid [Hbet][NTf2 ]. Dependent on the initial amount of chloride, the reaction temperature and the purity of the reagent, copper crystallizes in complexes with varying coordination geometries and ligands. Subsequently, the influence of these different complex species on electrochemical properties is shown. For the first time, copper is deposited from the ionic liquid [Hbet][NTf2 ], giving promising opportunities for more resource-efficient copper plating. The copper coatings were analyzed by SEM and EDX measurements. Furthermore, a mechanism for the decomposition of [Hbet][NTf2 ] in the presence of chloride is suggested and supported by experimental evidence.

Electrodeposition of ZnNi Alloys from Choline Chloride/Ethylene Glycol Deep Eutectic Solvent and Pure Ethylene Glycol for Corrosion Protection

The present work follows the trend to develop non-aqueous 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.

Synthesis and Dissolution of Metal Oxides in Ionic liquids and Deep Eutectic Solvents

Ionic liquids (ILs) and deep eutectic solvents (DESs) have proven to be suitable solvents and reactants for low-temperature reactions. To date, several attempts were made to apply this promising class of materials to metal oxide chemistry, which, conventionally, is performed at high temperatures. This review gives an overview about the scientific approaches of the synthesis as well as the dissolution of metal oxides in ILs and DESs. A wide range of metal oxides along with numerous ILs and DESs are covered by this research. With ILs and DESs being involved, many metal oxide phases as well as different particle morphologies were obtained by means of relatively simple reactions paths. By the development of acidic task-specific ILs and DESs, even difficultly soluble metal oxides were dissolved and, hence, made accessible for downstream chemistry. Especially the role of ILs in these reactions is in the focus of discussion.