Choline Chloride-ethylene Glycol Research Articles

Исследование обратимости электролитического порошка олова, полученного из ионной жидкости

In this paper, a promising new high-capacity anode material for lithium-ion batteries based on a highly dispersed search is considered. The powder was obtained using pulsed electrochemical cathodic reduction in an electrolyte from an ionic liquid choline chloride-ethylene glycol on a titanium vibrocathode. The discharge capacity of the anode material was 817 (mA·h)/g, which is close to the theoretically specific electrochemical capacity of tin 924 (mA·h)/g. The powder of the researchers for the dispersion and morphology of tin crystals. The particle size distribution of the particles with an increased fraction ratio of less than 0.1 μm and SEM-photographs of grains with a rhombohedral particle shape are presented. For research, we turned to this anode material the applied methods of electrochemical analysis: cyclic voltammetry, galvanostatic cycling and impedance spectroscopy in the process of charge and discharge of the electrode. Consideration of changes in the characteristics of the electrode under study using circuits for impedance spectroscopy during the formation of the lithium-tin intermetallic compound, as well as a change in the ratio It is shown that when the charging capacity is reached, close to theoretical intercalation can go through two ways: through SEI and intermetallic compound.

Electrochemical behavior and electrodeposition of Ni-Co alloy from choline chloride-ethylene glycol deep eutectic solvent

In this work, nickel-cobalt (Ni-Co) alloy was prepared in choline chloride-ethylene glycol deep eutectic solvent by deposition. Metal ion complex structure and stability were studied using UV–Vis. The electrochemical behavior in different metal salts was studied by voltammetry (CV) and chronoamperometry (CA). The corrosion resistance was studied using potentiodynamic polarisation and electrochemical impedance (EIS). Surface and phase composition of Ni-Co alloy coatings were characterized by scanning electron microscopy (SEM/EDS) and X-ray diffraction (XRD). The results from the voltammetry showed that the reduction peak appear among −0.6 V ∼ −1.13 V, which belonged to Ni-Co codeposition. The reduction of Ni-Co alloy in the CE was an irreversible process under diffusion control. Chronoamperometric results indicated that the electrodeposition of Ni-Co on a glassy carbon electrode followed the mechanism of instantaneous nucleation and three-dimensional growth. The results of microstructure and phase composition showed that the control of deposition potential could effectively control the microstructure and Co content of Ni-Co alloy. Nano crystal structure could be obtained with a grain size in the range of 3.1–4.0 nm. Comparison in the corrosion behaviour of the coatings showed that the change of Co content had an effect on the corrosion resistance of Ni-Co alloy.

Electrochemical fabrication of cobalt films in a choline chloride–ethylene glycol deep eutectic solvent containing water

The electrodeposition of cobalt from alternative electrolytes, including ionic liquids and deep eutectic solvents (DES), has become a topic of great interest to the scientific community, with a significant impact in both academic circles and in the development of commercial industrial electrochemical processes. However, very few studies have considered the effects of water on the electrodeposition of metals from deep eutectic solvents. In this work, the electrodeposition of Co from a choline chloride (ChCl) ethylene glycol (EG)-based deep eutectic solvent (DES) containing 10%, 20% and 30% water has been studied, and for the first time a uniform and bright Co deposit has been obtained when the deposition was achieved from an electrolyte containing 20% water. The speciation of Co in a mixed 1:2 ChCl:EG-based liquid (Ethaline 200) has been studied in both the absence and presence of water. The conductivities of the Co electrolyte were increased with increasing amounts of water. The electrochemical properties of the Co electrolytes have been studied using cyclic voltammetry, where it was found that the redox peak current gets larger and shifts in a positive direction when water was included in the Co solution. The resultant surface morphologies, topography, and roughness of the Co deposits were revealed by scanning electron microscopy (SEM) and atomic force microscopy (AFM), which demonstrated that a highly uniform and smooth cobalt coating had been produced when the deposition occurred in Ethaline 200 containing 20% water.

Effect of excess hydrogen bond donors on the electrode-electrolyte interface between choline chloride-ethylene glycol based solvents and copper

The fine tuning of deep eutectic solvents (DES) via the addition of co-solvents such as water or excess ethylene glycol, to improve the electrodeposition of metals is becoming increasingly common. However, as these changes become commonplace, our understanding of their effect must deepen as well. In this work, we look into how water, a secondary hydrogen bond donor (HBD), added to choline chloride:ethylene glycol (1:2 ChCl:EG) DES changes the electrochemical behaviour of the solution. We use time-of-flight secondary ion mass spectrometry (ToF-SIMS) to identify and map the organic molecules that have interacted with the surface. A copper surface was used as an electrochemically active substrate. The molecular maps provide insights into how solvent composition changes electrolyte reactivity, as well as showing the main driver behind the entrapment of organic compounds in metal deposits from DES. This behaviour was studied at different potentials based on the information provided by linear sweep voltammetry data of the copper in the solution. These results are then contrasted against a 1:4 ChCl:EG solution, where the excess ethylene glycol acts as secondary HBD, in order to determine the individual contributions of the co-solvents and how they affect the electrochemistry of the media and their reactions with the copper electrode. This information can be used as a set of guidelines for the tuning and optimisation of ethylene glycol based DES for metal deposition.

Electrodeposition of Sn–In Alloys Involving Deep Eutectic Solvents

Tin–indium alloys represent attractive lead-free solder candidates. They show lower values of melting point than pure indium, so that they are investigated as materials with significant applications potential in the electronic industry. Electrodeposition is a very convenient route to prepare Sn–In alloys. The paper presents several experimental results regarding the electrodeposition of Sn–In alloy coatings involving deep eutectic solvents (DESs), namely using choline chloride-ethylene glycol eutectic mixtures. The influence of the main operating parameters on the Sn–In alloy composition and characteristics are presented. Adherent and uniform Sn–In alloy deposits containing 10–65 wt % In have been obtained on Cu substrates. The In content was found to increase as both the In:Sn molar concentration ratio of ionic species in the electrolyte and the applied temperature increased. The use of pulsed current allowed the use of higher current densities leading to slightly higher values of In content in the alloy deposit. X-ray diffraction (XRD) analysis revealed the presence of InSn4 and In3Sn phases in agreement with the phase diagram. According to thermogravimetric analysis (TGA) measurements, values of melting points in the range of 118.6 and 127.5 °C were obtained depending on the alloy composition. The solder joints’ behavior and alloy coatings corrosion performance were also discussed.

CO2 -Philic Separation Membrane: Deep Eutectic Solvent Filled Graphene Oxide Nanoslits.

CO2 capture and sequestration is an energy-intensive industry to deal with the global greenhouse effect. Membrane separation is considered a cost-effective method to mitigate the emission of CO2 . Though good separation performance and stability have been reported, supported ionic liquid membranes are still not widely applied for CO2 separation due to the high cost. As a novel analogous solvent to ionic liquid, deep eutectic solvent retains the excellent merits of ionic liquid and is cheap with facile preparation. Herein, a highly CO2 -philic separation membrane is constructed by nanoconfining choline chloride/ethylene glycol (ChCl/EG) deep eutectic solvent into graphene oxide nanoslits. Molecular dynamic simulation results indicate that the confinement makes a difference to the structure of the nanoconfined ChCl/EG liquid from their bulk, which remarkably facilitates CO2 transport. By tuning the molar ratio of ChCl/EG and thickness of the membrane, the resultant membrane exhibits outstanding separation performance for CO2 with excellent selectivity over other light gases, good long-term durability, and thermal stability. This makes it a promising membrane for selective CO2 separation.

Controllable preparation of antimony powders by electrodeposition in choline chloride-ethylene glycol

Antimony powders with different morphologies have been prepared by electrodeposition at 313–353 K and 10–50 mA·cm−2 in 0.1 mol·L−1 SbCl3 + ChCl-EG solution. The electrochemical behavior of Sb(III) on titanium electrode are studied by cyclic voltammetry. Results show that the electrochemical reduction of Sb(III) in SbCl3 + ChCl-EG solution is a quasi-reversible process via a one-step reaction and the apparent activation energy is 50.723 kJ·mol−1. The effects of current density and temperature on current efficiency and specific energy consumption are also investigated. The current efficiency increases with the increasing of current density and temperature. The specific energy consumption increased with the increase of current density, while decreased with the raising of temperature. When the current density is 40 mA·cm−2 at 353 K, the current efficiency and specific energy consumption are up to 97.89% and 1251.277 kW·h·t−1, respectively. The morphology and phase of the products are analyzed by FESEM and XRD. It demonstrates that the deposition products are pure antimony powders and their preferred crystal plane is (0 1 2). The pineal, wheat grain, badminton, dendritic, and cluster-like antimony powders can be prepared by controlling electrodeposition parameters. The particles size range of antimony powders are 0.21–261.05 μm.

Electrochemical Impedance Study of Cast and ALM Stainless Steel Electropolishing in Acids Media and Deep Eutectic Solvents

Electropolishing (EP) process is now extensively used as a post-treatment particularly for additive manufacturing parts. This electrolytic dissolution process consists in a controlled dissolution of metallic surfaces leading to both surface roughness decrease and brightness increase, and is usually performed in concentrated acidic media. Interestingly, alternatives eco-friendly electrolytes depending on the metal type have been developed during the last years such as Deep Eutectic Solvents 1,2. Four distinct regions appear on a typical electropolishing polarization curve,3–5namely the active dissolution of the substrate after the oxide layer breakdown, a viscous film formation at the interface electrolyte/substrate (not always present), a limiting current plateau ascribed to a diffusion controlled mechanism (this corresponds to the electropolishing zone), and the solvent oxidation and oxygen evolution domain. Given the complexity of the electropolishing process, many mechanisms have been proposed. Among them, the most commonly accepted explanations consists in the presence of a resistive layer due to dehydratation, oxide formation or saturation of dissolved metal ions at the electrode interface. In this respect, the electropolishing mechanism was investigated by Linear Sweep Voltammetry (LSV) and Electrochemical Impedance Spectroscopy (EIS) for 316L Stainless Steel in phosphoric and sulfuric acid media and choline chloride-ethylene glycol mixtures. Then an extended study has concerned additive manufacturing parts. The control of the dissolution reaction by diffusion was confirmed with the linear dependence of the limiting current density vs.electrode rotation rate as described by the Levich’s law. Nevertheless, varying the viscosities by changing temperature from 35°C to 70°, show a direct relationship between the diffusion coefficient and the kinematic viscosities, irrespective of the cation concentration at the interface, which suggest a minor role in the diffusion limiting step. This limitation is therefore provided by the diffusion of an acceptor specie from the electrolyte toward the anode surface. To discriminate the role of water or mineral anion, a full descriptive model of the electrochemical behaviour of interface was developed, based on the corresponding hypotheses. This model found its roots in iron corrosion and electropolishing considerations.6Additionally, EIS measurements were carried out in acidic and DES media. This enable to confront experimental results with the theoretical model for the dissolution reaction. In the first case, water was assumed to be the limiting specie, whereas and in the second case an acceptor specie (as phosphates or chlorides) was considered. A similar study has been conducted for both cast and additive manufacturing 316L Stainless Steel in both acidic and DES media. In all cases, the proposed model allows to predict the electrochemical behaviour of the system. A. P. Abbott, G. Capper, K. J. McKenzie, A. Glidle, and K. S. Ryder, Phys. Chem. Chem. Phys., 8, 4214 (2006). C. Rotty, M.-L. Doche, A. Mandroyan, and J.-Y. Hihn, ECS Trans., 77, 1199–1207 (2017). C. Rotty, A. Mandroyan, M.-L. Doche, and J. Y. Hihn, Surf. Coat. Technol., 307, Part A, 125–135 (2016). C. A. Huang, J. H. Chang, W. J. Zhao, and S. Y. Huang, Mater. Chem. Phys., 146, 230–239 (2014). A. M. Awad, N. A. A. Ghany, and T. M. Dahy, Appl. Surf. Sci., 256, 4370–4375 (2010).J.-P. Diard, P. Landaud, J.-M. Le Canut, and B. Le Gorrec, in, 6ème Forum sur les Impédances Electrochimiques - Montrouge - France (1992). Figure 1

Urease Inhibitory Potential and Soil Ecotoxicity of Novel “Polyphenols–Deep Eutectic Solvents” Formulations

New formulations based on red grape pomace polyphenols and deep eutectic solvents (DES) have been here evaluated as inhibitors of urease of agricultural interest (jack bean urease, JBU). DES based on choline chloride (CHO) and betaine (BET), combined with ethylene glycol (EG), citric acid (CA), and urea (U), were used both as extracting and carrying agents for polyphenols, becoming active components of the formulations here obtained. Among the various DES combinations, U- and CA-based ones gave the best polyphenol extraction performances, 1.2–1.4-times higher than those of the hydroalcoholic mixture. Among the various DES–polyphenols formulations, the one composed by CHO–EG showed the best antioxidant potential and urease inhibition: 60–90% inhibition of the total JBU activity was achieved with a CHO concentration of 5–20 mM. Good results were also achieved with the BET–EG polyphenol formulation, which was able to inhibit ca. 50% of urease activity at 20 mM concentration of BET. Low phytotoxicity of DES a...

Strong Microheterogeneity in Novel Deep Eutectic Solvents.

With the increasing application of template assisted syntheses in deep eutectic solvents and successful application of hydrophobic deep eutectic solvents in extraction processes, where microheterogeneity plays a major role, suggestions for novel deep eutectic solvents which exhibit strong microheterogeneity are desirable. Therefore, classical molecular dynamics simulations were carried out on deep eutectic solvent systems constructed of choline chloride and some of its derivatives mixed with ethylene glycol in a molar composition of 1 : 2 since this is the optimal parent composition. The derivatives consisted of a series of elongated alkyl side chains and elongated alcohol side chains. Of these series only choline chloride ethylene glycol has been investigated experimentally, the other systems are suggested and theoretically investigated as possible target for synthesis. Our domain analysis supported by the clear distinction of polar and nonpolar parts from the electrostatic potentials reveals that strong microheterogeneity within these novel hypothetical deep eutectic solvents exists. Rather stretched than crumbled side chains maximize possible interaction sites for both polar and nonpolar parts which make the suggested compounds valuable objectives for experiments in order to exploit the microheterogeneity in deep eutectic solvents.

Electrodeposition of 1-D tellurium nanostructure on gold surface from choline chloride-urea and choline chloride-ethylene glycol mixtures

The electrodeposition of Te on Au substrate was investigated in either choline chloride-urea and in choline chloride-ethylene glycol deep eutectic solvents, at a molar ration of 1:2, containing 0.05 mol L−1 TeCl4. The electrodeposition of Te on Au electrode followed a three-dimensional progressive nucleation mechanism in both eutectic solvents. The diffusion coefficients of Te4+ species as a function of temperature were well fitted by a like-Arrhenius equation in both plating solutions. The apparent activation energies were 22.20 and 22.55 kJ mol−1 for Scharifker-Hills and Cottrell's models, respectively, in 1ChCl:2EG. On the other hand, in 1ChCl:2 U these values were 59.20 and 57.80 kJ mol−1. In addition, SEM micrographs of Te electrodeposits from both revealed a large-scale Te rods-like morphology with hexagonal cross-section in nanoscale regime uniformly distributed on electrode surface. TEM investigation suggested that Te single-crystalline grew perpendicular direction of (100) planes which implied in the preferential growth direction of [001].

Improving affinity of imprinted monolithic polymer prepared in deep eutectic solvent by metallic pivot

One of the major drawbacks of conventional molecularly imprinted polymers (MIPs) is the requirements of volatility porogenic solvent during polymerization. To overcome the default, MIP based on deep eutectic solvent (DES, a new type of green designer solvents) has been synthesized successfully. To improve the affinity of the MIP based on DES, in this work, a strategy of metallic pivot was suggested in the first time to prepare a highly selective MIP monolithic column. A cetirizine-imprinted polymer was prepared in a DES-based porogen system composed of choline chloride/ ethylene glycol (ChCl-EG) in the presence of Co(Ac)2 as metallic pivot. The resulting DES- Co2+-MIP monolith had 23.5 times higher imprinting factor than the Co2+-free MIP monolith. The characterization of polymers indicated that DES was one of the primary factor influencing the MIP morphology and pore structure. Compared with previous metal-mediated and ionic liquid-based imprinted polymers, the introduction of DES as a porogen in polymerization led to higher imprinting factor (approximately 2.9 - 17.1 times). In addition, the resulting DES-Co2+-MIP can be used as an adsorbent for extraction of cetirizine from ethanol solution with the recoveries of 97.8%. As a conclusion, the metallic pivot is a rather valuable strategy for the synthesis of DES-based MIP monolith with high selectivity.

Fabrication of Water-Compatible Molecularly Imprinted Resin in a Hydrophilic Deep Eutectic Solvent for the Determination and Purification of Quinolones in Wastewaters.

A novel water-compatible molecularly imprinted resin was prepared in a green solvent deep eutectic solvent (DES). Resorcinol and melamine, as functional monomers with an abundant hydrophilic group, such as –OH, –NH2 and –NH–, were introduced into the molecularly imprinted resin (MIR). Three DESs (choline chloride-ethylene glycol, tetramethylammonium bromide-ethylene glycol and tetramethylammonium chloride-ethylene glycol) were used to synthesize the molecularly imprinted resin and the resulting deep eutectic solvent-based molecularly imprinted resins were characterized by particle size analysis, elemental analysis, scanning electron microscopy, Fourier transform infrared spectroscopy and thermogravimetric analysis. The resulting deep eutectic solvent-based molecularly imprinted resins were then applied to the adsorption of quinolones (ofloxacin) in water. The adsorption process of deep eutectic solvent-based molecularly imprinted resin followed the static adsorption model, Langmuir isotherm (R2 ≥ 0.9618) and kinetic model pseudo-second-order (R2 > 0.9814). The highest theory adsorption ability of the three kinds of deep eutectic solvent-based molecularly imprinted resins was more than 23.79 mg/g. The choline chloride-ethylene glycol-based MIR was applied to solid-phase extraction for the determination and purification of quinolones (e.g., ciprofloxacin and ofloxacin). The detection limit of deep eutectic solvent-based molecularly imprinted resin-solid-phase extraction method was less than 0.018 mg/L. The recoveries of the deep eutectic solvent-based molecularly imprinted resin-solid-phase extraction method at three spiked levels were 88.7–94.5%, with a relative standard deviation of ≤4.8%. The novel deep eutectic solvent-based molecularly imprinted resin-solid-phase extraction method is a simple, selective and accurate pre-treatment method and can be used to determine the quinolones in environmental water.

Electrode-electrolyte interactions in choline chloride ethylene glycol based solvents and their effect on the electrodeposition of iron

Although deep eutectic solvents (DES) and ethylene glycol (EG) electrolytes are gaining ground as media for the electrodeposition of metals, the influence of these electrolytes on the electrode and electrodeposits has not been elaborated before. In this work, we investigate how choline chloride: ethylene glycol based (ChCl:EG) electrolytes interact with the glassy carbon (GC) working surface at different potentials and, how these interactions change during the electrodeposition of iron from 1:2 and 1:4 ChCl:EG electrolytes. GC substrates are exposed to both electrolytes in absence of iron in order to study the pure electrolyte-substrate interactions. Linear sweep voltammetry was used to determine the potential range in which the different reactions occur, while time-of-flight secondary ion mass spectrometry (ToF-SIMS) was used to detect and identify the molecules adsorbed on the surface. In all systems, there is an accumulation of either choline or its derivatives on the electrode surface, with 1:4 ChCl:EG electrolytes showing different decomposition products from 1:2 ChCl:EG electrolytes. Choline accumulation and decomposition was also found on iron electrodeposits. The electrolyte composition has a major impact on the chemical speciation of iron, and on the deposit's adherence to the substrate. These are two crucial characteristics that define the efficiency of iron deposition from DES.

Alternate Ultrasound/Microwave Digestion for Deep Eutectic Hydro-distillation Extraction of Essential Oil and Polysaccharide from Schisandra chinensis (Turcz.) Baill

An alternating synergetic ultrasound/microwave method was applied to the simultaneous extraction of essential oils and polysaccharides with deep eutectic solvent (DES) from Schisandra chinensis. Under the optimal conditions, extract in the selected choline chloride-ethylene glycol 1:3 solvent yielded 12.2 mL/kg and 8.56 g/100g of essential oils and polysaccharides, respectively. The free radical scavenging and immunological activities of the polysaccharides and the antioxidant activity of the essential oils have also been investigated. The lymphocyte proliferation capacity was substantially improved by adding concanavalin A or lipopolysaccharides to polysaccharides (0.20 mg/mL). The IC50 values of the essential oils for scavenging DPPH obtained by hydro-distillation and DES ultrasound/microwave-assisted hydro-distillation (DES UMHD) were 52.34 µg/mL and 29.82 µg/mL, respectively. The essential oil obtained by DES UMHD had the highest reducing power (856.05 (TE)/g) at 150 g/mL and had the strongest inhibitory capacity (SC% = 18.12%). S. chinensis has the potential to be developed as a natural antioxidant.

Galvanic Displacement Deposition of Bismuth on Copper in the Ambient Ethaline Deep Eutectic Solvent in the Absence and Presence of Water and Additives

A facile approach of forming bismuth (Bi) films on copper (Cu) substrates via galvanic displacement using the deep eutectic solvent (DES) Ethaline (choline chloride-ethylene glycol; ChCl-EG) as the reaction medium was studied. Electronic absorption spectra and cyclic voltammetric behavior implied that Cu atoms were displaced by Bi atoms via the consumption of Bi(III) complex ions and the formation of Cu(I) species; the latter was oxidized to Cu(II) under ambient air. It is evident that the concentration of Bi(III) in Ethaline as well as the reaction temperature affect the surface morphologies and crystallization of the formed Bi layers, which follows the conventional behavior of nucleation and growth similar to the electrodeposition. Water content in the Ethaline DES seemed to promote the galvanic displacement by decreasing the solution viscosity, and enhancing the mass transport rate of the reacting species. Additives such as cetyltrimethylammonium bromide (CTAB), and molecular thiourea (TU) showed significant effects on the surface morphologies of the Bi layers.

A highly efficient microextraction technique based on deep eutectic solvent formed by choline chloride and p-cresol for simultaneous determination of lignans in sesame oils

For simultaneous determination of lignans (i.e. sesamin, sesamolin and sesamol) in sesame oils, a highly efficient ultrasonic-assisted liquid–liquid microextraction (UALLME) technique was developed based on deep eutectic solvents (DESs) composed of choline chloride and p-cresol. Compared with the common polyols-based DESs (i.e. choline chloride-ethylene glycol), the phenolic DESs exhibited higher extraction efficiency for both polar lignans (i.e. sesamol) and non-polar lignans (i.e. sesamin and sesamolin) due to the π-π interaction between lignans and DES. After the UALLME process, DES phase was analyzed by HPLC-UV. Under optimized condition, all three lignans showed good linear calibration curves and low limit of detection. The recoveries were in the range of 97.3–120%, and the intra-day and inter-day precisions were less than 0.97%. Moreover, this method was used for simultaneous determination of lignans in 15 commercial oil samples. The results showed that the new microextraction technique achieved similar efficiency as the conventional liquid-liquid extraction method.

Electrodeposition of lead selenide films from ionic liquids based on choline chloride

The paper presents some experimental results regarding the electrodeposition of PbSe thin films at 70 °C from two choline chloride (ChCl) based ionic liquids containing PbCl2 and SeO2 as precursors in choline chloride-ethylene glycol (ILEG) and choline chloride-urea (IL) eutectic mixtures. In this article we will detail our investigation of cathodic processes involved during the electrodeposition of binary semiconductor compound, PbSe as well as of singular Pb and Se elements. The cathodic branches of the recorded cyclic voltammograms in the cases of ionic liquids containing both Pb2+ + Se4+ show successively the Se underpotential deposition, Se bulk deposition and Pb deposition followed by a formation of PbSe semiconductor compound. However, at the most negative potentials the Se content of final layers decreases by a partial electrochemical dissolution of Se which reduces to Se2− soluble species.PbSe thin films have been electrodeposited on copper or nickel substrates under potentiostatic control at 70 °C for 0.5–4 h. The adherent and uniform deposits were characterized by SEM-EDX and XRD techniques. SEM images have shown adherent and grey deposits with uniform morphology and cubic PbSe crystals. A stoichiometry of around Pb1.1Se was indicated by EDX elemental analysis. XRD confirmed the formation of PbSe compound, showing a nanocrystalline structure, with crystallites average sizes in the range of 10–35 nm.

Direct Electrodeposition of Phosphorus-Doped Nickel Superstructures from Choline Chloride–Ethylene Glycol Deep Eutectic Solvent for Enhanced Hydrogen Evolution Catalysis

Hydrogen produced by electrochemical water splitting offers a hopeful and renewable solution to address the global energy crisis; however, development of highly efficient hydrogen generation electrocatalysts remains a big challenge. Herein, self-supported P-doped nickel superstructure films (NiPx) developed on Cu foil were prepared via a facile one-step electrodeposition route from the choline chloride–ethylene glycol (Ethaline)-based deep eutectic solvent (DES). Two depositional patterns including potentiostatic deposition and a consecutive potential cycling approach were compared, and the latter model with a potentiodynamic control was found to be a valid electrochemical protocol to create crack-free NiPx films which were highly active for catalyzing hydrogen evolution reaction (HER) under an alkaline condition. The optimal deposited sample with a Ni/P ratio of 1:0.056 achieved a low overpotential of 105 mV to deliver a current density of 10 mA cm–2 with a small Tafel slope of 44.7 mV dec–1 and excellen...

Corrosion behavior of zinc coating electroplated at high current from a deep eutectic solvent

A Zinc coating was electroplated in choline chloride-ethylene glycol system at high current density in atmosphere. The crystal structure, surface and cross-section morphologies, chemical elements of electroplated zinc coating were analyzed by x-ray diffraction and scanning electron microscopy with line analysis, respectively. The bending and corrosion performances were also discussed in this study. The results indicate that the zinc coating presents a highly (110) texture with small flake zinc grains stacked on the surface. The zinc coating exhibits well bonding with the copper substrate though no obvious diffusion layer was observed. The corrosion performance of zinc coating displays a combine system of the electrode process and diffusion process without passivation process.