Using Electrodeposition of Carboxylated Chitosan for Green Preparation of Copper Nanoclusters and Nanocomposite Films

On the basis of coordinated electrodeposition of carboxylated chitosan(CCS),we presented a green method to prepare Cu NCs and Cu NCs/CCS nanocomposite films.The method shows a range of benefits,such as the convenient and eco-friendly process,mild conditions,and simple post-treatment.The experimental results reveal that a homogeneous deposited film(Cu NCs/CCS nanocomposite film)is generated on the Cu plate(the anode)after electrodeposition,which exhibits an obvious red florescence.The results from TEM observation suggest there are nanoparticles(with the average particle size of 2.3 nm)in the deposited film.Spectral analysis results both demonstrate the existence of Cu NCs in the deposited film.Moreover,the Cu NCs/CCS film modified electrode is directly created through electrodeposition of CCS,which enables promising application in the electrochemical sensing.By means of fluorescence properties of Cu NCs,the Cu NCs/CCS film also owns the potential in fluorescence detection.Therefore,this work builds a novel method for the green synthesis of Cu NCs,meanwhile it offers a convenient and new electrodeposition strategy to prepare polysaccharide-based Cu NCs nanocomposites for uses in functional nanocomposites and bioelectronic devices.

Reshaping Li–Mg hybrid batteries:Epitaxial electrodeposition and spatial confinement on MgMOF substrates via the lattice‐matching strategy

The emergence of Li–Mg hybrid batteries has been receiving attention,owing to their enhanced electrochemical kinetics and reduced overpotential.Nevertheless,the persistent challenge of uneven Mg electrodeposition remains a significant impediment to their practical integration.Herein,we developed an ingenious approach that centered around epitaxial electrocrystallization and meticulously controlled growth of magnesium crystals on a specialized MgMOF substrate.The chosen MgMOF substrate demonstrated a robust affinity for magnesium and showed minimal lattice misfit with Mg,establishing the crucial prerequisites for successful heteroepitaxial electrocrystallization.Moreover,the incorporation of periodic electric fields and successive nanochannels within the MgMOF structure created a spatially confined environment that considerably promoted uniform magnesium nucleation at the molecular scale.Taking inspiration from the“blockchain”concept prevalent in the realm of big data,we seamlessly integrated a conductive polypyrrole framework,acting as a connecting“chain,”to interlink the“blocks”comprising the MgMOF cavities.This innovative design significantly amplified charge‐transfer efficiency,thereby increasing overall electrochemical kinetics.The resulting architecture(MgMOF@PPy@CC)served as an exceptional host for heteroepitaxial Mg electrodeposition,showcasing remarkable electrostripping/plating kinetics and excellent cycling performance.Surprisingly,a symmetrical cell incorporating the MgMOF@PPy@CC electrode demonstrated impressive stability even under ultrahigh current density conditions(10mAcm^(–2)),maintaining operation for an extended 1200 h,surpassing previously reported benchmarks.Significantly,on coupling the MgMOF@PPy@CC anode with a Mo_(6)S_(8) cathode,the assembled battery showed an extended lifespan of 10,000 cycles at 70 C,with an outstanding capacity retention of 96.23%.This study provides a fresh perspective on the rational design of epitaxial electrocrystallization driven by metal–organic framework(MOF)substrates,paving the way toward the advancement of cuttingedge batteries.

Influence of sodium silicate on manganese electrodeposition in sulfate solution

The influences of sodium silicate on manganese electrodeposition in sulfate solution were investigated. Manganese electrodeposition experiments indicate that a certain amount of sodium silicate can improve cathode current efficiency and initial pH 7.0?8.0 is the optimized pH for high cathode current efficiency. The analyses of scanning electron microscopy (SEM) and X-ray diffraction (XRD) indicate the compact morphology and nanocrystalline structure of electrodeposits. X-ray photoelectron spectrometry (XPS) analysis shows that the elements of Mn, Si and O exist in the deposit. The solution chemistry calculations of sulfate electrolyte and sodium silicate solution indicate that species of Mn2+, MnSO4, Mn(SO4)2?2 , Mn2+, MnSiO3, Mn(NH3)2+, SiO32?and HSiO3? are the main active species during the process of manganese electrodeposition. The reaction trend between Mn2+ and Si-containing ions is confirmed by the thermodynamic analysis. In addition, polarization curve tests confirm that sodium silicate can increase the overpotential of hydrogen evolution reaction, and then indirectly improve the cathode current efficiency.

α-Ni(OH)2 electrodeposition from NiCl2 solution

α-Ni(OH)2 was synthesized from a NiCl2 solution by electrodeposition method.In order to conduct a systematic study on the effects of experimental parameters,a series of electrolyte initial pH values,current densities,electrodeposition temperatures,and electrodeposition time were used.Cyclic voltammetry results demonstrated a side reaction of Ni^2++2e→Ni.The X-ray diffraction analysis,Fourier-transform infrared spectrum,and the color of the product showed that pureα-Ni(OH)2 could be obtained in the initial pH value range of 2−5.86,current density range of 10−25 mA/cm^2,electrodeposition temperature range of 25−35℃,and electrodeposition time range of 1.0−3.0 h.When electrodeposition temperature increased to 45℃,a mixture ofα-Ni(OH)2 and metallic Ni was obtained.A current density higher than 30 mA/cm^2 resulted in the sample with features ofβ-Ni(OH)2.A small amount of metallic Ni existed in the as-prepared sample when current density decreased to 5 mA/cm^2.A slight increase of electrolyte pH was observed with increasing initial solution pH and current density.Electrodeposition mass revealed a slight decrease with initial pH decreasing and showed an almost linear increase with current density increasing.The slope of the curve for electrodeposition mass versus electrodeposition time remained stable in the first 2.0 h and then decreased.

Microstructure and deposition mechanism of electrodeposited Cu/liquid microcapsule composite

The nanostructured copper/microcapsule containing liquid core materials composite（copper/liquid microcapsules composite） was prepared using direct current（DC） electrodeposition method.The surface morphology and microstructure of composite were investigated by means of scanning electron microscopy（SEM）,transmission electron microscopy（TEM） and X-ray diffraction（XRD）.The results show that the microstructure of electrodeposited layer transformed from bulk crystal to nano structure because of the participation of microcapsules.The diameters of microcapsules and the copper grain sizes in the composite were 2？20 μm and 10？20 nm,respectively.In addition,the electrodeposition mechanism of composite in the deposition process followed electrochemistry theory,which was proved by the theoretical analysis result and the experiment results.Meanwhile,the co-deposition process model was presented.

Electrodeposition of Al on AZ31 magnesium alloy in TMPAC-AlCl_3 ionic liquids

Aluminum was electrodeposited with constant current on AZ31 magnesium alloy pretreated under optimized conditions from trimethyl-phenyl-ammonium chloride and anhydrous aluminum chloride （TMPAC-AlCl3） quaternary ammonium room temperature ionic liquids with benzene as a co-solvent. The corrosion resistance of the as-deposited Al layers was evaluated in 3.5% NaCl solution by the electrochemical technologies. The Al depositions were characterized by scanning electron microscopy equipped with energy dispersion X-ray. The results show that the microstructures of the Al depositions have spherical equiaxed grains obtained at a high current density, and bulk grains at a low current density. The Al deposition obtained at 12.3 mA/cm2 has a smooth and compact surface. The electrochemical measurements indicate that the thicker Al deposition can more effectively protect the Mg substrate. The Al deposition with bulk grains hardly protects the AZ31 Mg substrate from corrosion owing to its porosity.

Electrodeposition behavior of bright nickel in air and water-stable betaine·HCl-ethylene glycol ionic liquid

The electrodeposition behaviors of nickel on glassy carbon（GC） and carbon steel（CS） electrodes were investigated in the14.3%-85.7%（mole fraction） betaine.HCl ethylene glycol（EG） ionic liquid using cyclic voltammetry and chronoamperometry.The results indicated that the reduction of Ni（Ⅱ） on CS electrode via a diffusion-controlled quasi-reversible process was much more facile and easier than that occurred on GC electrode,which followed a diffusion-controlled three-dimensional instantaneous nucleation and growth.Scanning electron microscopy was used to observe that the deposit was dense and contained fine crystallites with average size of（80±4） nm.Energy dispersive spectrometer analysis showed that the obtained deposit was metallic nickel.X-ray diffraction spectroscopy indicated that（111） plane was the most preferred crystal orientation.The nickel deposit was luminous and bright,and had good adhesion with the CS substrate.

Electrodeposition and corrosion resistance of Ni-P-TiN composite coating on AZ91D magnesium alloy

In order to improve the corrosion resistance and microhardness of AZ91D magnesium alloy, TiN nanoparticles were addedto fabricate Ni-P-TiN composite coating by electrodeposition. The surface, cross-section morphology and composition wereexamined using SEM, EDS and XRD, and the corrosion resistance was checked by electrochemical technology. The results indicatethat TiN nanoparticles were doped successfully in the Ni-P matrix after a series of complex pretreatments including activation, zincimmersion and pre-electroplating, which enhances the stability of magnesium alloy in electrolyte and the adhesion betweenmagnesium alloy and composite coating. The microhardness of the Ni-P coating increases dramatically by adding TiN nanoparticlesand subsequent heat treatment. The corrosion experimental results indicate that the corrosion resistance of Ni-P-TiN compositecoating is much higher than that of uncoated AZ91D magnesium alloy and similar with Ni-P coating in short immersion time.However, TiN nanoparticles play a significant role in long-term corrosion resistance of composite coatings.

Catalytic graphitization of PAN-based carbon fibers with electrodeposited Ni-Fe alloy

Ni-Fe alloy was electrodeposited on the surface of polyacrylonitrile （PAN）-based carbon fibers, and catalytic graphitization effect of the heat-treated carbon fibers was investigated by X-ray diffractometry and Raman spectra. It is found that Ni-Fe alloy exhibits significant catalytic effect on the graphitization of the carbon fibers at low temperatures. The degree of graphitization of the carbon fibers coated with Ni-Fe alloy （57.91% Fe, mass fraction） reaches 69.0% through heat treatment at 1 250 °C. However, the degree of graphitization of the carbon fibers without Ni-Fe alloy is only 30.1% after being heat-treated at 2 800 °C. The catalytic effect of Ni-Fe alloy on graphitization of carbon fibers is better than that of Ni or Fe at the same temperature, indicating that Ni and Fe elements have synergic catalytic function. Furthermore, Fe content in the Ni-Fe alloy also influences catalytic effect. The catalytic graphitization of Ni-Fe alloy follows the dissolution-precipitation mechanism.

Electrodeposition of cobalt in double-membrane three-compartment electrolytic reactor

The process parameters were optimized for the electrodeposition of cobalt from cobalt chloride solution in the membrane electrolytic reactor. Effects of parameters such as catholyte composition, current density and temperature on the current efficiency, specific power consumption and quality of deposition were studied. The catholyte was a mixed solution of cobalt chloride, the initial middle electrolyte consisted of diluted hydrochloric acid, and the anolyte was sulfuric acid. An anion exchange membrane separated the catholyte from the middle electrolyte, and a cation exchange membrane separated the anolyte from the middle electrolyte. The results showed that a maximum current efficiency of 97.5% was attained under the optimum experimental condition of an catholyte composition of 80 g/L Co^2＋, 20 g/L H3BO3, 3 g/L NaF and pH of 4, at a cathode current density of 250 A/m2 and a temperature of 50 ℃ HCl could be produced in the middle compartment electrochemically up to 0.45 mol/L.

Effect of boron/phosphorus-containing additives on electrodeposited CoNiFe soft magnetic thin films

CoNiFe,CoNiFeB and CoNiFeP soft magnetic thin films were prepared by cyclic voltammetry method.The morphologies,composition and structures were characterized by scanning electron microscope（SEM）,energy-dispersive X-ray spectroscope（EDS） and X-ray diffractometer（XRD）.The soft magnetic properties were investigated through vibrating sample magnetometer（VSM）.The corrosion resistance was investigated through Tafel polarization and electrochemical impedance spectroscopic（EIS）.The results show that all the electrodeposited CoNiFe,CoNiFeB and CoNiFeP films are mixtures of crystalline and amorphous phases,and high amount of boron/phosphorus-containing additives favors the formation of amorphous state.Nanostructure is obtained in CoNiFe and CoNiFeB films.The inclusion of boron causes the film more dense and also increases its corrosion resistance.Meanwhile,the inclusion of boron lowers its coercivity（Hc） from 851.48 A/m to 604.79 A/m,but the saturation magnetic flux density（Bs） is almost unchanged.However,the addition of phosphorus greatly increases the film particle size and decreases its corrosion stability.The coercivity（Hc） of CoNiFeP film is also highly increased to 12485.79 A/m,and its saturation magnetic flux density（Bs） is greatly decreased to 1.25 T.

CeO_2/Zn NANOCOMPOSITE COATING BY ELECTRODEPOSITION

The nanocomposite coating is obtained by electrochemical deposition of the zinc plating solution with ceria nanoparticles (mean diameter 30 nm). The effect of ceria nanoparticles on the electrodeposited zinc coating is stu died by weight loss test, inductively copuled plasma quantometer (ICP), scanning electron microscopy (SEM) and X ray diffraction (XRD), respectively. It is found that under the same electrodeposition conditions, the corrosion resistance of the nanocomposite coating increases obviously while that of the micron composite coating only improves slightly; The ceria content of the nanocomposite coating is more than that of the micron composite coating. Ceria nanoparticles modify the surface morphology and crystal structure of the zinc matrix in correlation with the increase of corrosion resistance.

Electrodeposition of Cu_2O/g-C_3N_4 heterojunction film on an FTO substrate for enhancing visible light photoelectrochemical water splitting

An immobilized Cu2O/g-C3N4 heterojunction film was successfully made on an FTO substrate by electrophoretic deposition of g-C3N4 on a Cu2O thin film.The photoelectrochemical（PEC） performance for water splitting by the Cu2O/g-C3N4 film was better than pure g-C3N4 and pure Cu2O film.Under-0.4 V external bias and visible light irradiation,the photocurrent density and PEC hydrogen evolution efficiency of the optimized Cu2O/g-C3N4 film was-1.38 mA/cm^2 and 0.48 mL h^-1 cm^-2,respectively.The enhanced PEC performance of Cu2O/g-C3N4 was attributed to the synergistic effect of light coupling and a matching energy band structure between g-C3N4 and Cu2O as well as the external bias.

Fabrication of superaligned carbon nanotubes reinforced copper matrix laminar composite by electrodeposition

A new kind of laminar metal matrix nanocomposite（MMC） was fabricated by an electrodeposition process with copper and superaligned carbon nanotubes film（SACNT film）.The SACNT film was put on a titanium plate and then a layer of copper was electrodeposited on it.By repeating the above process,the laminar Cu/SACNT composite which contains dozens or hundreds of layers of copper and SACNT films was obtained.The thickness of a single copper layer was controlled by adjusting the process parameter easily and the thinnest layer is less than 2 μm.The microscopic observation shows that the directional alignment structure of SACNT is retained in the composite perfectly.The mechanical and electrical properties testing results show that the tensile and yield strengths of composites are improved obviously compared with those of pure copper,and the high conductivity is retained.This technology is a potential method to make applicable MMC which characterizes high volume fraction and directional alignment of carbon nanotubes.

Electrodeposition of As-Sb alloy from high arsenic-containing solutions

As-Sb alloy was electrodeposited from high arsenic-containing solutions. The influences of current density, Sb（3＋） concentration, reaction temperature and HCl concentration on the electrolyte composition, cell voltage and current efficiency were investigated. The surface morphology, composition and structure of the deposits were analyzed by scanning electron microscopy（SEM）, inductively coupled plasma mass spectrometry（ICP-MS） and X-ray diffraction（XRD）, respectively. The results show that the prepared As-Sb alloy shows an amorphous structure under all conditions. Under the optimized condition, i.e., 10 g/L As（3＋）, 2 g/L Sb（3＋）, 4 mol/L HCl, current density of 4 mA/cm2 and temperature of 20 °C, desired As-Sb alloy with a composition of 70.26% As and 29.74% Sb（mass fraction） is obtained. What is more, the current efficiency is as high as 94.74% and high arsenic removal rate is achieved under this condition.

Electrodeposition of iridium from composite ionic liquid

In order to study the electrodeposition process of iridium in composite ionic liquid, the effects of N, N-dimethylacetamide（DMAC） on the viscosity, conductivity and electrochemical stability of composite ionic liquid BMIC-BMIBF4, as well as the electrochemical behavior of Ir Cl3 in this system were studied. Iridium（Ir） coatings were deposited at different constant potentials and characterized by SEM and XRD. The results show that the addition of DMAC can evidently decrease the viscosity of the composite system, increase conductivity and improve electrochemical stability of the composite system. Cyclic voltammograms of a Au electrode illustrate that the process controlled by diffusion rate is irreversible with the average charge transfer coefficient of 0.170 and average diffusion coefficient of 1.096×10-6 cm^2/s. In addition, SEM image shows that Ir film deposited at the reduction peak potential is dense and even, while XRD pattern shows that Ir deposit is polycrystalline structure.

FABRICATION OF Bi NANOWIRE ARRAY BY ELECTRODEPOSITION TECHNOLOGY

In the fabrication of Bi nanowire array thermoelectric materials,electrodeposition technology has been used to deposit bismuth into the nanopores of anodic alumina porous films.The experiments show that the temperature significantly affects the electrodepositing process,and the simple form of Bi 3+ in the solutions is helpful to the deposition of metal Bi.The pulse plating technique is necessary for the electrodeposition because of the diffusive difficulty of Bi 3+ into the nanopores of the films.The XRD analysis indicates that Bi nanowire arrays have been manufactured by this technology.

Electrodeposition of Ir on platinum in NaCl-KCl molten salt

The reduction mechanism of Ir in the NaCl-KCl-IrCl3 molten salt was investigated by cyclic voltammetry and chronopotentiometry, and Ir film was deposited effectively on platinum in potentiostatic mode. The morphology and constitution of Ir film were examined by scanning electron microscopy （SEM）, energy dispersive spectroscopy （EDS） and X-ray diffraction （XRD）. It is found that the reduction mechanism of Ir（III） is a three-electron step and electro reaction is a reversible diffusion controlled process; the diffusion coefficients of Ir（III） at 1083, 1113, 1143 and 1183 K are 1.56×10-4, 2.23×10-4, 2.77×10-4 and 4.40×10-4 cm2/s, respectively, while the activation energy of the electrode reaction is 102.95 kJ/mol. The compacted Ir film reveals that the applied potential greatly affects the deposition of Ir, the thickness of Ir film deposited at the potential of reduction peak is the highest, the temperature of the molten salt also exerts an influence on deposition, the film formed at a lower temperature is thinner, but more micropores would occur on film when the temperature went too high.

Effect of La_2O_3/Ce O_2 particle size on high-temperature oxidation resistance of electrodeposited Ni-La_2O_3/Ce O_2 composites

Ni-La2O3/CeO2 composite films were prepared by electrodeposition from a nickel sulfate bath containing certain content of micrometer and nanometer La2O3/CeO2 particles. The effect of La2O3 or CeO2 particle size on the oxidation resistance of the electrodeposited Ni-La2O3/CeO2 composites in air at 1000 °C was studied. The results indicate that, compared with the electrodeposited Ni-film, Ni-La2O3/CeO2 composites exhibit a superior oxidation resistance due to the codeposited La2O3 or CeO2 particles blocking the outward diffusion of nickel. Moreover, compared with nanoparticles, La2O3 or CeO2 microparticles have stronger effect because La2O3 or CeO2 microparticles also act as a diffusion barrier layer at the onset of oxidation.

Electrodeposition and characterization of nano-structured black nickel thin films

The electrodeposition and characterization of nano-structured black nickel coatings were presented. The influences of bath pH, electrodeposition time, stirring speed, temperature and current density on the color and microstructure of the electrodeposited nickel film were investigated through naked eyes, scanning electron microscopy （SEM） and X-ray diffraction （XRD） techniques. Meanwhile, the corrosion resistance of the optimized black nickel film was evaluated by the polarization measurement and electrochemical impedance spectroscopy （EIS） in the neutral 3.5% NaC1 solution. The results show that the color of the electrodeposited nickel film was highly dependent on the above technological parameters. The operating parameters were optimized mainly according to the color. The optimized black nickel film possesses nano-structure with an average grain diameter of about 50 nm. It also exhibits enhanced corrosion resistance when compared with white nickel coatings electrdodeposited under the same condition except the variation of the electroplating current density.