Copper Electrodeposition from Deep Eutectic Solvents—Voltammetric Studies Providing Insights into the Role of Substrate: Platinum vs Glassy Carbon

Abstract

We report on the effect of the substrate on electrochemical deposition of Cu from deep eutectic solvent ethaline. We investigated the polarization behavior during electrodeposition of Cu on Pt and glassy carbon (GC) from both Cu 2+ and Cu + containing ethaline using cyclic voltammetry (CV). Formation of bulk Cu deposits on both substrates underwent nucleation and growth processes; however, the nucleation was considerably sluggish on GC compared to Pt. While experiments in Cu + solutions indicated that coalescence of Cu islands on Pt is a slow process and that its surface may not be fully covered by Cu, such determination of Cu coverage could not be made on GC. Cu dissolution is also slower from GC than from Pt. It was observed that CV of Cu deposition on GC is influenced by the surface preparation method. Since ethaline has high chloride concentration, a parallel study in aqueous 3 M NaCl solution was conducted in order to examine the influence of the chloride medium on the electrodeposition process. This revealed that electrodeposition in both media occurred in the same manner but with different charge and mass transfer rates caused by the differences in viscosity and chloride concentrations of the two solutions.

Direct Laser Writing of Copper Micropatterns from Deep Eutectic Solvents Using Pulsed near-IR Radiation

“…It is also worth mentioning methods of pattern fabrication, such as roll-to-roll (R2R) gravure printing [ 4 ] and copper electrodeposition [ 5 , 6 ]. Despite these methods offering the valuable advantage of a high production rate, these technologies, nevertheless, require expensive equipment and enormous volumes of copper plating solutions.…”

Copper Deposition on Au(111) in a Deep Eutectic Solvent: An In Situ STM Study**

“…Considering that ethaline DES is highly‐concentrated with chloride, which is in favor of forming stable Cu(I) and Cu(II) chlorocomplexes, comparative studies in aqueous solutions containing 3 M NaCl were also carried out by Setastian et al [25] . and later Vukmirovic et al [31] . Both groups suggest that the conversion of Cu(II) and Cu(I) and Cu depositon proceed generally in same manners in the aqueous solution, although they are more facile than in DES.…”

“…[23,24] In addition, highlyconcentrated multi-components contained in DES electrolytes may also play key roles in manipulating bulk properties of electrolytes and interfacial processes during Cu deposition. [30,31] Researches on Cu electrodeposition in DES have already been carried out. In 2009, Abbott et al reported first study of Cu electrodeposition on Pt electrodes from two DES, i. e. ureacholine chloride (named reline) and ethylene glycol-choline chloride (named ethaline) containing CuCl 2 salts by cyclic voltammetry and chronoamperometry.…”

“…In 2014, Sebastián et al [30] investigated Cu deposition on glassy carbon electrode in reline and demonstrated viability of Schrifsker-Hills model [32,33] in DES and Cu deposition follows 3D instantaneous nucleation and growth at sufficient highly overpotential. Considering that ethaline DES is highly-concentrated with chloride, which is in favor of forming stable Cu(I) and Cu(II) chlorocomplexes, comparative studies in aqueous solutions containing 3 M NaCl were also carried out by Setastian et al [25] and later Vukmirovic et al [31] Both groups suggest that the conversion of Cu(II) and Cu(I) and Cu depositon proceed generally in same manners in the aqueous solution, although they are more facile than in DES. Zhang et al, reported that Cu deposition can take place by dissolving Cu 2 O into DES, supporting the capability of concentrated Cl ions in stabilizing Cu(I).…”

Metal mobility and toxicity of reclaimed copper smelting fly ash and smelting slag

“…24 The copper and zinc in RCS y ash and smelting slag can be leached using water or dilute sulfuric acid, and the leaching solution and leach residue can be treated using other methods. [25][26][27] However, limited information was found regarding the metal mobility and toxicity of RCS y ash and smelting slag.…”