Progress in Electrodeposition of Zinc and Zinc Nickel Alloys Using Ionic Liquids

Electrodeposition of Ni nanoparticles from deep eutectic solvent and aqueous solution promoting high stability electrocatalyst for hydrogen and oxygen evolution reactions

Nanostructured Ni films were synthesized from two distinct baths and were assessed as electrocatalysts for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in 1 M KOH. Herein, Ni was electrodeposited from two separate solvents, the aqueous acetate buffer and ethaline solvent as a kind of deep eutectic solvents (DESs), and both the deposited films were investigated as electrocatalysts for HER and OER. The electrodeposition parameters such as pH and deposition potential were studied. The electrodeposition process was performed using chronoamperometry technique and Ni deposits were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX), and X-ray diffraction (XRD). Fabricated Ni@PGE deposit from ethaline only requires an overpotential of − 154 mV and 350 mV to achieve a current density of 10 mA cm−2 for HER and OER, respectively. While, Ni@PGE from acetate requires an overpotential of − 164 mV and 400 mV to produce the current density of 10 mA cm−2 for HER and OER.

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Design and Preparation of Imidazole Ionic Liquid-Based Magnetic Polymers and Its Adsorption on Sunset Yellow Dye

Magnetic polymers are often used as loading materials for ionic liquids because of their excellent magnetic separation properties. In this study, a novel imidazolium-based ionic liquid-modified magnetic polymer was synthesized by suspension polymerization and grafting, denoted as γ-Fe₂O₃@GMA@IM, and this magnetic polymer was used for the adsorption of the acid dye FCF. The magnetic polymer was characterized by SEM, FTIR, XRD, VSM and TGA. These techniques were used to reveal the overall physical properties of magnetic polymers, including the presence of morphology, functional groups, crystalline properties, magnetism and thermal stability. Studies have shown that γ-Fe₂O₃@GMA@IM can adsorb FCF in a wide pH range (2–10), with a maximum adsorption capacity of 445 mg/g. The adsorption data were more in line with the pseudo-second-order kinetic model and the Freundlich isotherm. In order to investigate its reusability, this study used 10% NaCl as the desorption solution, and carried out five batches of adsorption–desorption cycles. After five cycles, the adsorption effect was maintained at 98.3%, which showed a good recycling performance.

A Preliminary Assessment of the ‘Greenness’ of Halide-Free Ionic Liquids—An MCDA Based Approach

With the growing interests in non-aqueous media for diversified applications, ionic liquids (ILs) are frequently considered as green solvents. While the environmental, health, and safety assessments of the commercially developed ILs and their ‘greenness’ status are in debate, research focus is shifting towards the application of halide-free ILs for diversified applications. To clarify the situation on their greenness, and to understand if they really possess safe characteristics, we performed an initial assessment of 193 halide free ionic liquids composed of four groups of cations (imidazolium, pyridinium, pyrrodilinium, piperidinum) and 5 groups of anions (acetate, propionate, butyrate, alkanesulfonates, alkylsulfates). The ‘Technique for Order of Preference by Similarity to Ideal Solutions’ (TOPSIS), a multi-criteria decision analysis (MCDA) tool that allows ranking many alternatives is applied by carrying out the assessment against 14 criteria that includes hazard statements, precautionary statements, biodegradability, and toxicity towards different organisms. The ranking results obtained against the set of criteria considered show that the halide free ILs placed between recommended polar solvents: methanol and ethanol can be considered to be safer alternatives in terms of ‘greenness’. The study in this work provides an initial assessment of the halide-free ionic liquids evaluated against 14 criteria in terms of their safety characteristics (“green character”) using the MCDA-TOPSIS approach.

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.