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Thin films of Cu2CoSnS4 (CCTS) are electrodeposited onto fluorine tin oxide substrate using pulsed electrodeposition mode for various time periods followed by sulfurization treatment at 500 °C. The pulse potential (V1) is held constant at 0 V vs. Ag/AgCl, while (V2) is set at − 1.1 V vs. Ag/AgCl. The effect of pulse duration on the CCTS proprietress is being investigated. Cyclic voltammetry was used to study the electrochemical behaviors of Cu–Co–Sn–S precursors, while in situ electrochemical impedance spectroscopy investigated the electrical properties of the system during electrodeposition of CCTS at − 1.10 V. The impedance spectra revealed a capacitive loop pattern along with Warburg diffusion. The samples were analyzed by X-ray diffraction (XRD), Raman spectroscopy, and UV–visible spectroscopy. Both XRD data and Raman spectra indicated that the CCTS thin films have a stannite structure. The films deposited for 20 min and 30 min exhibit a predominantly pure CCTS phase. Moreover, deposition for 20 min exhibits a homogeneous morphology with a nearly stoichiometric composition along with an optical band gap energy of 1.54 eV. Apart from the CCTS phase, noticeable secondary phases are present in films deposited at both low and high pulse durations, and they have been observed to slightly affect the gap energy. [ABSTRACT FROM AUTHOR]

This study investigates the preparation of nickel nanostructured electrodes for the enhancement of supercapacitor performance. The nanostructured electrodes are synthesized using nanoporous anodic alumina (NAA) as a template via the pulsed electrodeposition method. Structural properties are examined using field‐emission scanning electron microscopy, while electrochemical characterization is conducted through cyclic voltammetry (CV) and electrochemical impedance spectroscopy. The results reveal that Ni nanorod arrays can be obtained embedded in the NAA matrix and with electrical contact with the aluminum substrate. On average, the rods are spaced 90 nm apart, with a diameter of 70 nm and a length of 2 μm. The Ni@NAA electrode exhibits an enlarged active area and exceptional electrochemical performance, demonstrating remarkable stability over 5000 cycles of CV at a scan rate of 50 mV s−1. Specific capacitance values exceeding 100 mF cm−2 and maximum charging times of less than 10 min are reported, highlighting its suitability for high‐power energy devices requiring pseudo‐supercapacitance. The study underscores the significance of nanostructured electrodes in advancing energy storage technologies and presents promising prospects for practical applications. [ABSTRACT FROM AUTHOR]

A low-roughness ultra-thin copper foil was prepared by pulsed electrodeposition with a duty cycle 60%, pulse frequency of 600 Hz on titanium. The influence of sodium 3,3'-dithiodipropane sulphonate (SPS), hydroxyethyl cellulose (HEC), gelatin and collagen additives on the microstructure, mechanical properties and electrochemical behaviour of electrolytic copper foil was explored. Furthermore, the reaction mechanism of SPS and collagen additives on electrodeposited copper were discussed. The results showed that at 0.08 g L−1 collagen concentration, the lowest thickness, the highest microhardness and the optimal surface roughness were achieved (5.12 μm, 279.63 HV and 1.885 μm, respectively). X-ray diffraction results confirmed that electrolytic copper foils prepared when SPS was introduced into the blank solution had a preferred orientation of (220) texture, which benefitted from the synergistic effect of copper ions and additives. The intermediates formed by the additive and Cu+ occupied the active sites on the cathode surface that increased the nucleation sites for deposition. In addition, the formed complexes can act as a barrier to narrow ion deposition channels and inhibit the growth of Cu ions. [ABSTRACT FROM AUTHOR]

The demand for more efficient and sustainable electrical systems has driven research in the quest for innovative materials that enhance the properties of electrical conductors. This study investigated the influence of copper (Cu) coating and multi-walled carbon nanotubes (MWCNTs) on aluminum metal substrate through the pulsed electrodeposition technique. Parameters such as the concentration of chemical elements, current, voltage, temperature, time, and electrode spacing were optimized in search of improving the nanocomposite coating. The metallic substrate underwent anodization as surface preparation for coating. Characterization techniques employed included Field Emission Gun—Scanning Electron Microscopy (FEG-SEM) for analyzing coating morphology, Energy-Dispersive X-Ray Spectroscopy (EDS), Raman spectroscopy, and Kelvin probe for obtaining surface electrical conductivity values. Homogeneous dispersion of the Cu-MWCNTs film coating was achieved across the entire surface of the aluminum plate, creating a complex morphology. The doping effect was highlighted by changes in the vibrational characteristics of the nanocomposite, which affected the Raman spectrum dispersion bands. An increase in surface electrical conductivity by ≈52.33% compared to the control sample was obtained. Therefore, these results indicate that the improvement in the material's electrical properties is intrinsically related to the complex morphology achieved with the adopted Cu-MWCNT nanocomposite coating process. [ABSTRACT FROM AUTHOR]

In this work the synthesis, characterization and photocatalytic activity of novel graphene oxide-supported ZnO nanostructured film are reported. The ZnO film was deposited onto GO layer in a two-step procedure varying the deposition mode. The electrodeposited ZnO films were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform Infrared (FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS). The effect of the electrodeposition mode and GO presence on the properties of the ZnO nanostructured film was assessed. The applicability towards the adsorption, photodegradation of methylene blue (MB) for the obtained films was analyzed. The results indicated the electrodeposition pulses result in a strong interaction between ZnO and GO results, lower c-axis strain of the deposited ZnO and higher oxygen vacancies. Synergistic effect of oxygen vacancies and morphology towards degradation performance was indicated. Both adsorption and photocatalysis towards the degradation of MB on the modified ZnO films were observed, 52 % degradation efficiency being recorded in 90 min with a rate constant of 0.00171 min−1 under low UV irradiation, with respect to 5 % corresponding to ZnO film obtained in single step by direct mode and in absence of GO layer. A recycling experiment indicated excellent stability of the photocatalyst, the degradation efficiency reaching 98 % after 3 successive runs. [ABSTRACT FROM AUTHOR]

Flexible sensor arrays with multilevel circuits typically require complex production cycles leading to high costs and reliability issues. For establishing flexible arrays of strain sensors in Wheatstone bridge configurations structures on different levels within flexible films have to be connected by robust μ-via technology. Usually, dry etching is used to establish via-holes and direct current (DC) electrodeposition is used to fill them with copper. However, dry etching can lead to damages in the underlying electrode or incomplete removal of polymeric material, as inhomogeneities of polymeric foil thicknesses cannot completely be eliminated. This affects the quality of the plating and the reliability of the μ-via connections. It is aggravated by the fact that DC electroplated copper is often weakened by various defects, such as small voids. This article describes a reliable and less complex fabrication process for a Wheatstone bridge sandwich structure consisting of five polymer interlayers separating four metal layers. The femtosecond-laser μ-via drilling proved to be fast, material selective and therefore tolerant to inhomogeneities of polymeric foil thicknesses. Moreover, pulsed current (PC) electrodeposition significantly improved the quality of the copper filling. No voids were found using electron microscopy. Finally, the respiration monitoring sensors produced using this method were subjected to repetitive cycles of bending and relaxation. At a frequency of five cycles per second, reproducible cycles of signal changes were obtained, indicating the usefulness for detecting respiratory cycles of premature infants.

The demand for more efficient and sustainable electrical systems has driven research in the quest for innovative materials that enhance the properties of electrical conductors. This study investigated the influence of copper (Cu) coating and multi-walled carbon nanotubes (MWCNTs) on aluminum metal substrate through the pulsed electrodeposition technique. Parameters such as the concentration of chemical elements, current, voltage, temperature, time, and electrode spacing were optimized in search of improving the nanocomposite coating. The metallic substrate underwent anodization as surface preparation for coating. Characterization techniques employed included Field Emission Gun—Scanning Electron Microscopy (FEG-SEM) for analyzing coating morphology, Energy-Dispersive X-Ray Spectroscopy (EDS), Raman spectroscopy, and Kelvin probe for obtaining surface electrical conductivity values. Homogeneous dispersion of the Cu-MWCNTs film coating was achieved across the entire surface of the aluminum plate, creating a complex morphology. The doping effect was highlighted by changes in the vibrational characteristics of the nanocomposite, which affected the Raman spectrum dispersion bands. An increase in surface electrical conductivity by ≈52.33% compared to the control sample was obtained. Therefore, these results indicate that the improvement in the material’s electrical properties is intrinsically related to the complex morphology achieved with the adopted Cu-MWCNT nanocomposite coating process.

In this work, we reported a method of preparing Cu 2 ZnSnS 4 @TiO 2 nanotubes (Cu 2 ZnSnS 4 /TiO 2 NTs) composite electrode by pulse electrodeposition and high-temperature vulcanization, which possesses high catalytic conversion efficiency for CO 2 reduction and stable performance. In addition, the influence of pulse parameters on the morphology and photoelectrochemical properties of Cu 2 ZnSnS 4 /TiO 2 NTs composite electrode were studied in detail. The band gap of Cu 2 ZnSnS 4 /TiO 2 NTs is 1.39 eV, which is significantly reduced compared with TiO 2 NTs (3.27 eV). There are differences in the morphology, catalytic efficiency and product selectivity of the catalytic interface constructed by different pulse electrodeposition parameters. The photoresponse current of the composite electrode prepared by optimizing the parameters reaches −7 μA cm−2, and the ethanol yield is 7.0 μmol cm−2 after 5 h of photoelectrocatalytic reduction of CO 2. No new phase was generated and the photocurrent density remained 33.2% of the original after the catalytic process, which indicated the Cu 2 ZnSnS 4 /TiO 2 NTs possess stable catalytic performance. [Display omitted] • A new method was developed to prepare self-assembled composite electrode for catalytic reduction of CO 2. • Cu 2 ZnSnS4/TiO 2 NTs electrode exhibited good photoelectrocatalytic ability and high selectivity of ethanol. • The p-n junction Cu 2 ZnSnS 4 /TiO 2 NTs was obtained by optimizing pulse parameters. • The high temperature sulfidation enabled the Cu 2 ZnSnS 4 /TiO 2 NTs electrode stable in performance. [ABSTRACT FROM AUTHOR]

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The copper recovery from waste printed circuit boards is of great significance to protect natural resource and environment. Direct current electrodeposition has been applied to extract metal from hydrometallurgical leach solutions. However, during the direct current electrodeposition process, concentration polarization and hydrogen evolution reaction often exist, which reduces current efficiency and metal recovery capability. In this work, a pulse current was applied to electrodeposit copper. The electrolyte was the leach solution of waste printed circuit boards obtained using a sulfuric acid-hydrogen peroxide system. The influence of process parameters in the leaching stage and the electrodeposition process on current efficiency were both investigated. The results showed that the current efficiency was 95.1% in pulse current electrodeposition, while that was only 90.9% in direct current electrodeposition. The increased current efficiency was proposed to be attributed to the fact that pulse current electrodeposition could improve the mass transfer of copper ions which suppressed concentration polarization and hydrogen evolution reaction. These results demonstrate that pulse current electrodeposition is a promising approach for recovering copper from waste-printed circuit boards. [ABSTRACT FROM AUTHOR]

In this study, Al coatings were pulse electrodeposited from a molten salt electrolyte onto copper substrates. The effects of applied peak current density, pulse current frequency and duty cycle on the morphology, microstructure, corrosion behaviour and tribological properties of the coatings were investigated by scanning electron microscopy, X-ray diffraction, potentiodynamic polarisation, electrochemical impedance spectroscopy and pin-on-disc wear test methods. The results showed that the changes in processing parameters changed the morphological and microstructural features of the resulting coatings, which in turn affected their corrosion and wear behaviours. Coatings with smoother surfaces, finer crystallite size and more compact morphologies that were electrodeposited at higher applied peak current density (up to 80 mA cm−2), higher pulse current frequency (up to 50 Hz) and higher duty cycle (up to 50%) exhibited more corrosion and wear resistance than the others. [ABSTRACT FROM AUTHOR]

Porous templates are widely used for the preparation of various metallic nanostructures. Semiconductor templates have the advantage of controlled electrical conductivity. Site-selective deposition of noble metal formations, such as Pt and Au nanodots and nanotubes, was demonstrated in this paper for porous InP templates prepared by the anodization of InP wafers. Metal deposition was performed by pulsed electroplating. The produced hybrid nanomaterials were characterized by scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX). It was shown that uniform deposition of the metal along the pore length could be obtained with optimized pulse parameters. The obtained results are discussed in terms of the optimum conditions for effective electrolyte refreshing and avoiding its depletion in pores during the electroplating process. It was demonstrated that the proposed technology could also be applied for the preparation of metal nanostructures on porous oxide templates, when it is combined with thermal treatment for the oxidation of the porous semiconductor skeleton. [ABSTRACT FROM AUTHOR]

Herein, a facile pulse electrodeposition procedure with a 1 s off-time between pulses is reported for a successful fabrication of porous nickel oxide (NiO) films on an indium tin oxide substrate. Large transmittance modulation of 39.2% at 550 nm, fast switching speed (coloring and bleaching of 5.2 s and 2.3 s), high coloration efficiency of 20.01 cm2 C−1, and long-term stability over 750 cycles were achieved. In comparison to the NiO films synthesized by continuous electrodeposition, the porous morphology of the NiO fabricated by pulsed electrodeposition facilitates charge transfer and electrolyte infiltration, as well as reduces the expansion/shrinkage of the NiO lattice during OH− insertion/extraction, resulting in an outstanding electrochromic performance. These results show that pulsed electrodeposition is a promising method for manufacturing NiO films with enhanced EC performance. [ABSTRACT FROM AUTHOR]

Pulse electroplated copper has recently received a great deal of attention from the copper foil and microelectronics industries, as its remarkable microstructure is closely linked to several key properties, including the availability of metallic materials with reduced porosity, fine deposited grains and low electrical resistance. The effects of pulse superimposed direct current (DC) on the microstructure and properties of copper foils were investigated by taking advantage of the high deposition rate of pulse current and the long-term stability and easy control of DC current. Further, tests such as scanning electron microscopy (SEM) and confocal laser microscopy (CLM) were used to characterize the surface micromorphology of the copper foils, and the influence of the self-annealing effect at ambient temperature was explored using electron backscattering diffraction (EBSD). The results show that pulsed superimposed DC can obtain copper foils with a small profile and high tensile strength with a Sz of only 0.670 μm, σ ust 538.67 MPa and an elongation of 4.90%. Further, the specific additive MESS effectively suppresses the mechanical property degradation caused by self-annealing of copper foils, with a tensile strength reduction of only 0.39%. • A novel electrodeposition method of pulsed superimposed DC current has been developed for the preparation of highly extended copper foils. • Low profile copper foils are obtained when pulse plating is performed first. • MESS can effectively inhibit the degradation of mechanical properties caused by self-annealing of copper foils. [ABSTRACT FROM AUTHOR]

This study presents a kinetic determination of copper removal from a real jewelry industry wastewater, with removal reaching 82.49% at 37°C, using fast galvanic pulse electrochemical technique in a process lasting 115 min. In the temperature range from 20 to 40°C, the mathematical model of the pseudo-first-order irreversible rate equation, with a correlation coefficient of 0.99, described the process behaviour. In this same temperature range, the Arrhenius' equation described the system, in which the temperature increase favoured the reaction kinetics. The scanning electron microscope (SEM), with energy-dispersive X-ray detector (EDX), X-ray photoelectron spectroscopy (XPS) results, and the mathematical model fitting at the temperatures of 10 and 50°C indicated the formation of copper oxide I. [ABSTRACT FROM AUTHOR]

The better understanding of magnetization reversal in impurity added magnetic nanowires (NWs) would allow for their efficient use in future anisotropic spintronic devices. Herein, a pulsed electrodeposition method was employed to fabricate CoCr NW arrays in anodic aluminum oxide membranes with different pore diameters ranging from 30 to 60 nm. Hysteresis loop and first-order reversal curve measurements were used to evaluate magnetic properties and reversal modes of the resulting NWs, indicating the effective role of the NW diameter in the magnetization reversal. While a soft magnetic phase with local magnetostatic interactions was observed for 60 nm diameter NWs, soft and hard magnetic phases together with a wide distribution of magnetic interactions were evidenced for CoCr NWs with a diameter of 30 nm. A transverse domain wall mode was estimated to be responsible for the magnetization reversal at the diameter of 30 nm, whereas a combination of vortex and transverse domain wall propagation played a role at diameters equal and greater than 40 nm. The magnetic characteristics of the CoCr NWs were found to arise from changes in the magnetocrystalline anisotropy contribution oriented along the [100] direction, weakening coercivity, and squareness when increasing the NW diameter. [ABSTRACT FROM AUTHOR]

Bi2Te3 nanowires with diameters ranging from 25 to 270 nm, ultra-high aspect ratio, and uniform growth front were fabricated by electrodeposition, pulsing between zero current density during the off time and constant potential during the on time (pulsed-current-voltage method, p-IV). The use of zero current density during the off time is to ensure no electrodeposition is carried out and the system is totally relaxed. By this procedure, stoichiometric nanowires oriented perpendicular to the c-axis is obtained for the different diameters of porous alumina templates. In addition, the samples show a uniform growth front with ultra-high aspect ratio single crystal nanowires. The high degree of crystallinity was verified by transmission electron backscatter diffraction. This characterization revealed that the nanowires present both large single crystalline areas and areas with alternating twin configurations.

Pb-Co anodes have been considered an attractive candidate for oxygen evolution reaction (OER) applications due to their low overpotential to catalyze the OER and its low cost. Despite these characteristics, their efficiency to produce oxygen at high current densities is low. In this work, we report a Pb-Co-Sn film with enhanced efficiency and improved electrocatalytic properties. Pulsed cathodic electrodeposition was used to develop Pb-Co-Sn films at different deposition times among 2 and 10 min. Polarization curves were recorded to determine the deposition parameters. Morphological studies showed that the films grown for 6 min exhibited a well-covered and homogeneous surface. Structural analyses were recorded employing X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HR-TEM) that showed a nanostructured film composed by Pb and CoSn2 nanocrystallites. The electrochemical behavior of the developed Pb-Co-Sn films was measured by polarization curves in a sulfuric acid solution demonstrating a great ability to catalyze the OER: a reduction of the overpotential by 55% and 8.5% versus a Pb-Ca-Sn anode and Pb-Co film, respectively, accompanied by a strong increase in the current density. Thus, the addition of tin to the anode has a positive effect on the electrocatalytic performance of the film. [ABSTRACT FROM AUTHOR]

Despite the introduction of selenic acid for anodic porous alumina (APA) preparation with small nanopore diameters (< 20 nm), no attempt has been made to use it in the fabrication of small-diameter magnetic and metallic nanowire arrays. In this paper, considering the high cost of selenic acid, it has been attempted to initially use oxalic acid in preparation of an ordered pattern in the first anodization step and then employ selenic acid for the second anodization step by matching the appropriate voltage. By investigating the nanopore formation pattern in both acids, it was shown that the nanopores formed in the selenic acid had considerably smaller diameter (13 nm) than that of oxalic acid (35 nm). Under optimized conditions of electrodeposition, various metals were then grown in the selenic APA templates in order to fabricate nanowires with small diameters. The pore-filling percentage and crystalline properties were also investigated. [ABSTRACT FROM AUTHOR]

A nickel–indium (Ni–In) ferromagnetic alloy is successfully synthesized through a facile pulsed electrodeposition method. The composition, structure, and morphology are analyzed through atomic absorption spectroscopy (AAS), X‐ray diffraction (XRD), X‐ray photoelectron spectroscopy (XPS), and electron microscopy. The composition and structural analysis indicate fcc phase for the Ni43In57 and Ni63In37 alloys. The Ni–In alloy shows mixed phases when the Ni content is increased from 63 to 66 at%. Thermal analysis of the Ni63In37 results in an activation energy of 46 and 557 kJ mol−1 that can arise from the grain growth phenomena and phase transformation, respectively. Thermomagnetic studies show a Curie temperature of 340 °C for the Ni–In alloy with 63 at% Ni that also exhibits a saturation magnetization of 36 emu g−1. [ABSTRACT FROM AUTHOR]

The paper describes the use of pulse plating on-times outside the usual window in reliable measurement of the surface area of complex parts. Two methods are discussed and analysed; (i) the first based on double layer capacity effects, (ii) the second based on a diffusion-limited-current method. In particular, in cases where the surface area changes significantly with the growth of the deposited layer continuous measurement of the surface area using these techniques is a very useful tool. Examples of complicated shaped parts successfully treated are given. [ABSTRACT FROM AUTHOR]

A series of Co–P–TiO2 nanocomposite coatings were prepared via pulsed electrodeposition technique. TiO2 nanoparticles were embedded into the coating matrix using TiO2 sol. The phase constituents of nanocomposites were identified using X-ray diffraction. The surface morphology of nanocomposites was obtained through scanning electron microscopy. Wear tests and corrosion tests were conducted to determine the coating performance. Electrochemical characterization was performed by electrochemical impedance spectroscopy analysis. The nanocomposite coatings made via conventional pulse electrodeposition had a relatively ordered surface morphology and enhanced mechanical behaviour, which is associated with the increased strengthening effect of embedded nanoparticles. When applying a pulse reverse current, the Co–P–TiO2 nanocomposite coating had improved corrosion resistance owing to its smooth and uniform surface morphology. [ABSTRACT FROM AUTHOR]

In this paper, we have focused on the characterization of CoFe2O4 thin films grown on FTO substrate by pulsed electrodeposition technique followed by an annealing treatment in air at 500°C during 24 h. The formation of a polycrystalline structures that exhibit cubic spinel phase with an average crystallite size of 45 nm is investigated by XRD and FT-IR studies. SEM observations indicate that the shape of crystallites changes as the number of applied cycles increases. The surface profilometry measurements show that surface roughness of CoFe2O4 thin films varies from 116 nm to 229 nm with the number of applied cycles. The optical band gap of the samples was determined to be in the range 1.74–1.98 eV. [ABSTRACT FROM AUTHOR]

A disposable nonenzymatic glucose sensor was obtained by pulsed electrodeposition of Pt-CuO on a graphite pencil electrode (GPE). The morphology of the modified GPE was studied using SEM, and the chemical composition of the coating was examined by EDAX and XRD. The electrochemical response of the modified GPE was compared with individual copper- and platinum-modified GPEs. The electrodeposition parameters were optimized with respect to the electrocatalytic activity of the deposits towards glucose oxidation. Best operated at a working potential of 0.6 V vs. Ag/AgCl, the sensor has a sensitivity of 2035 μA mM−1 cm−2, a 0.1 μM detection limit and a wide linear response range that extends up to 25 mM. It is highly selective for glucose in the presence of various exogenous and endogenous interfering species. Eventhough the requirement of alkaline medium for sensing is a limitation, easy fabrication procedure, very high sensitivity and selectivity, wide analytical range, and disposable sensor characteristics show potential application towards blood glucose determination. [ABSTRACT FROM AUTHOR]

Although sodium ion batteries (SIB) have shown great potential for large-scale energy storage systems, the development of high-performance anode materials for SIB is crucial for their progress. However, the cycling performance of SIB is currently limited by severe volume changes during the sodiation/desodiation process. To overcome this problem, a bi-active metal alloying strategy has been proposed. In this study, we utilized pulsed electrodeposition to prepare bismuth-antimony alloy anode materials. The resulting Bi 44.9 Sb 55.1 alloy anode exhibited exceptional specific capacity, rate performance, and stability. After the second cycle, the discharge/charge capacities were 505.3 mAh·g−1/496.7 mAh·g−1 at 1 A·g−1, with a coulombic efficiency of over 98 %. Even after 50 cycles, the capacities remained at 494.7 mAh·g−1/481.9 mAh·g−1 with a capacity retention rate of 97.9 %. These excellent properties were attributed to the stable structure and suitable voids for electron transport and ion diffusion in the Bi 44.9 Sb 55.1 alloy, which effectively mitigated volume expansion during cycling. The reaction kinetics and mechanism were studied using cyclic voltammetry, in situ X-ray diffraction, and nuclear magnetic resonance techniques. Our work provides valuable insights for the development of bi-active metal alloy anodes for SIB. [ABSTRACT FROM AUTHOR]

A kind of novel anti-wear Ni-TiC composite coatings was deposited successfully on 42CrMo steel by pulsed electrodeposition method with various TiC particles concentration. The effect of TiC concentration on morphologies and properties of Ni-TiC composite coatings were investigated and the optimum concentration of TiC particle was obtained. Results demonstrate that TiC particles were distributed uniformly in the Ni-based coatings and Ni-TiC composite coatings consisted of refined nickel nanocrystalline size. When the TiC particles concentration was 32 g/L, the highest volume percentage of TiC particles with 23.9 Vol.% and maximum micro-indentation hardness of the Ni-TiC composite coatings with 475 HV were achieved. Ni-TiC composite coatings show significant improvement in wear resistance in comparison with TiC free Ni-P coating.

Bi2Te3 nanowires with diameters ranging from 25 to 270 nm, ultra-high aspect ratio, and uniform growth front were fabricated by electrodeposition, pulsing between zero current density during the off time and constant potential during the on time (pulsed-current-voltage method, p-IV). The use of zero current density during the off time is to ensure no electrodeposition is carried out and the system is totally relaxed. By this procedure, stoichiometric nanowires oriented perpendicular to the c-axis is obtained for the different diameters of porous alumina templates. In addition, the samples show a uniform growth front with ultra-high aspect ratio single crystal nanowires. The high degree of crystallinity was verified by transmission electron backscatter diffraction. This characterization revealed that the nanowires present both large single crystalline areas and areas with alternating twin configurations. [ABSTRACT FROM AUTHOR]

Bi2Te3 nanowires with diameters ranging from 25 to 270 nm, ultra-high aspect ratio, and uniform growth front were fabricated by electrodeposition, pulsing between zero current density during the off time and constant potential during the on time (pulsed-current-voltage method, p-IV). The use of zero current density during the off time is to ensure no electrodeposition is carried out and the system is totally relaxed. By this procedure, stoichiometric nanowires oriented perpendicular to the c-axis is obtained for the different diameters of porous alumina templates. In addition, the samples show a uniform growth front with ultra-high aspect ratio single crystal nanowires. The high degree of crystallinity was verified by transmission electron backscatter diffraction. This characterization revealed that the nanowires present both large single crystalline areas and areas with alternating twin configurations. [ABSTRACT FROM AUTHOR]

Cobalt–graphene nanocomposite coatings possess unique mechanical and tribological properties which attract researchers to explore its potential for various industrial applications. This research work presents the investigation on cobalt–graphene nanocomposite coatings, with two different graphene compositions cobalt–graphene (0.15 and 0.45 wt%) prepared by pulsed electrodeposition from aqueous bath involving cobalt chloride, trisodium citrate, and citric acid on low carbon steel substrate. Studies on coating morphology, microhardness, tribological characteristics such as wear and corrosion for the cobalt–graphene nanocomposite coatings were reported. Cobalt–graphene (0.45 wt%) nanocomposite coating which exhibits low wear rate in all load conditions due to the self-lubricating property of graphene and cobalt–graphene (0.15 wt%) nanocomposite coating shows higher corrosion resistance due to its layered cauliflower surface morphology. [ABSTRACT FROM AUTHOR]

Abstract The hydrogen evolution reaction (HER) for pulsed electrodeposited alloy of nickel cobalt and nickel cobalt magnesium cathode is studied using linear polarization and electrochemical impedance spectroscopy (EIS). EIS is performed at Heyrovsky hydrogen evolution rate determining step. The rate of Hydrogen evolution per unit area is determined. The Field Emission Gun Scanning Electron Microscopy (FEGSEM) shows the roughness of the sample. The X-ray diffraction shows the nickel cobalt deposited in face centered cubic (FCC) structure and nickel cobalt magnesium deposited in mixed phase of Ni Mg, Ni Co, and Co Mg. The Equivalent circuit for EIS spectrum is modeled with two CPE (Constant phase element) and Warburg impedance, and fitted using Complex Nonlinear Least Square fitting (Levenberg-Marquardt) method. The Tafel region of hydrogen evolution rate determining step is modeled using Heyrovsky step kinetic equation. The pulsed electrodeposition method of preparing HER cathode improves the structural growth and surface roughness which in turn increases surface hydrogen atom coverage. Highlights • Comparative study of hydrogen evolution behavior of electrodeposited nickel cobalt and nickel cobalt magnesium electrode. • Modeling electrode kinetics in the region Heyrovsky root of hydrogen gas production. • Modeling Electrochemical Impedance spectroscopy using combination of Warburg and faradaic circuit element. • Nickel cobalt magnesium electrode showed better performance in hydrogen production. [ABSTRACT FROM AUTHOR]

The effect of microstructure on the efficiency of shielding or shunting of the magnetic flux by permalloy shields was investigated in the present work. For this purpose, the FeNi shielding coatings with different grain structures were obtained using stationary and pulsed electrodeposition. The coatings’ composition, crystal structure, surface microstructure, magnetic domain structure, and shielding efficiency were studied. It has been shown that coatings with 0.2–0.6 µm grains have a disordered domain structure. Consequently, a higher value of the shielding efficiency was achieved, but the working range was too limited. The reason for this is probably the hindered movement of the domain boundaries. Samples with nanosized grains have an ordered two-domain magnetic structure with a permissible partial transition to a superparamagnetic state in regions with a grain size of less than 100 nm. The ordered magnetic structure, the small size of the domain, and the coexistence of ferromagnetic and superparamagnetic regions, although they reduce the maximum value of the shielding efficiency, significantly expand the working range in the nanostructured permalloy shielding coatings. As a result, a dependence between the grain and domain structure and the efficiency of magnetostatic shielding was found.

The research and development of suitable cathode materials for Zn2+ storage is crucial to meet the large-scale energy storage application of zinc-ion batteries (ZIBs). However, manganese-based oxide cathodes, the most-studied category of cathode materials, suffer from capacity decline and weak electrical conductivity. Herein, Ni-doped ZnMn 2 O 4 /Mn 2 O 3 nanocomposite has been synthesized using pulsed potential electrodeposition technique and then applied as cathode material for ZIBs. The Ni2+ doping effectively boosts the electrical conductivity and electrochemical performance of electrodes. Furthermore, simultaneous production of ZnMn 2 O 4 /Mn 2 O 3 nanocomposite as a two-phase compound and incorporation of Ni2+ in crystal structure leads to an improvement in reversibility and cyclability of Ni-doped ZnMn 2 O 4 /Mn 2 O 3 nanocomposite. Moreover, the Ni-doped ZnMn 2 O 4 /Mn 2 O 3 nanocomposite presents a specific capacity of 235.10 mAh g−1 (0.2 A g−1), higher than Undoped nanocomposite (215 mAh g−1). Besides, the Ni-doped ZnMn 2 O 4 /Mn 2 O 3 nanocomposite shows superior electrochemical performance, with a reversible capacity of 114.67 mAh g−1 and capacity retention of 91.32%, obtained after 3000 cycles at 2 A g−1, while the Undoped -ZnMn 2 O 4 /Mn 2 O 3 nanocomposite possesses the capacity of 61.85 mAh g−1 with 64.54% capacity retention at the same condition. The obtained results suggest that the synergistic effect of doping and two-phase compound synthesis provide new features for the practical application of ZIBs. [Display omitted] • Ni-doped ZnMn 2 O 4 /Mn 2 O 3 nanocomposite was obtained by pulsed potential electrodeposition. • Ni doping improved the conductivity of nanocomposite. • The synergistic effect of Ni doping and two-phase composing boosted ZIBs rate performance and capacity. • The Ni-doped ZnMn 2 O 4 /Mn 2 O 3 nanocomposite showed excellent long-term stability as cathode material for ZIBs. [ABSTRACT FROM AUTHOR]

Strategies to improve tensile strength and ductility of pulsed electrodeposited nanocrystalline Co-Cu were investigated. Parameters of deposition, which are pulse current density, duty cycle, and pulse-on time were adjusted to produce nanocrystalline Co-Cu deposits with different microstructures and morphologies. The most significant improvement of strength and ductility was observed at nanocrystalline Co-Cu deposited, at a low duty cycle (10%) and a low pulse-on time (0.3 ms), with a high pulse current density (1000 A/m2). Enhancement of ductility of nanocrystalline Co-Cu was also obtained through annealing at 200 °C, while annealing at 300 °C leads to strengthening of materials with reduction of ductility. In the as deposited state, tensile strength and ductility of nanocrystalline Co-Cu is strongly influenced by several factors such as concentration of Cu, grain size, and processing flaws (e.g., crystal growth border, porosity, and internal stresses), which can be controlled by adjusting the parameters of deposition. In addition, the presence of various microstructural features (e.g., spinodal and phase decomposition), as well as recovery processes induced by annealing treatments, also have a significant contribution to the tensile strength and ductility.

Nanostructured NiFe film was obtained on silicon with a thin gold sublayer via pulsed electrodeposition and annealed at a temperature from 100 to 400 °C in order to study the effect of heat treatment on the surface microstructure and mechanical properties. High-resolution atomic force microscopy made it possible to trace stepwise evolving microstructure under the influence of heat treatment. It was found that NiFe film grains undergo coalescence twice—at ~100 and ~300 °C—in the process of a gradual increase in grain size. The mechanical properties of the Au/NiFe nanostructured system have been investigated by nanoindentation at two various indentation depths, 10 and 50 nm. The results showed the opposite effect of heat treatment on the mechanical properties in the near-surface layer and in the material volume. Surface homogenization in combination with oxidation activation leads to abnormal strengthening and hardening-up of the near-surface layer. At the same time, a nonlinear decrease in hardness and Young’s modulus with increasing temperature of heat treatment characterizes the internal volume of nanostructured NiFe. An explanation of this phenomenon was found in the complex effect of changing the ratio of grain volume/grain boundaries and increasing the concentration of thermally activated diffuse gold atoms from the sublayer to the NiFe film.

CoFeCu nanowires were deposited by pulsed electrodeposition technique into the porous alumina templates by a two-step mild anodization technique, using the single-bath method. The electrodeposition was performed in a constant electrolyte while Cu constant was controlled by electrodeposition current. The electrodeposition current was 3.5, 4.25, 5 and 6 mA. The effect of electrodeposition current and annealing on the magnetic behavior of the nanowires was investigated. Nanowires were fabricated with 30nm diameter and 100nm inter-pore distance with both bcc-CoFe and fcc- Cu phases. With increasing the electrodeposition current the Cu content decrease and the coercivity and magnetization increase up to its optimum value, then decrease. Annealing improved the coercivity, maximum coercivity was obtained for sample fabricated at 5 mA current. After annealing the magnetization decrease for all sampls. The X-ray diffraction pattern of the sample at electrodeposition current 3.5 mA after annealed indicates that Cu and CoFe phases separately was formed and separate peak related to CoFeCu alloy structure is not seen.

Method of deposition of Electro-catalyst plays a significant role in the sensing behavior of electrochemical sensors for hydrogen. Amperometric hydrogen sensor operating in fuel cell mode with Nafion as proton conducting electrolyte, platinum as sensing and counter electrodes has been developed. A comparative study of response behavior of hydrogen sensors with brush coated, electrodeposited and pulsed electrodeposited Pt on gas diffusion electrode (GDE) was undertaken in the concentration range of 0–4 % H 2 /Ar. The crystal structure and microstructure of Pt/GDE were characterized by gracing incidence X-ray diffraction and field emission scanning electron microscopy. In-situ electrochemical impedance spectroscopy was carried out for the sensors with H 2 /Ar at sensing electrode side. The investigations revealed that Pt/GDE fabricated by pulsed electro-deposition has better sensitivity, response time and stability compared to the brush-coated and electrodeposited Pt/GDE sensors. Improved response of sensor with Pt/GDE fabricated by pulsed electro-deposition is explained based on microstructure of Pt electro-catalyst and interfacial characteristics of electrodes with Nafion. [ABSTRACT FROM AUTHOR]

Pulsed electrodeposition has been introduced to deposit ultrathin flakes of Co3O4 nanocrystals on ZnO nanorods. By fixing the seeding process, the scaffolding function of ZnO nanorods was studied by varying deposition times (30 s, 60 s, and 90 s) of Co3O4 at a nucleation current of −1.0 mA cm−2. The amount of deposited Co3O4 has a strong influence on the oxygen evolution performance with ZnO scaffolds. To deliver a current density of 10.0 mA cm−2 in neutral solutions (0.5 M K2SO4), the presence of ZnO scaffold electrodes negatively shifted the overpotential by ∼200 mV. In particular, the Co3O4/ZnO hybrid nanostructured electrode (60 s) exhibits the lowest onset potential of 1.5 V (vs. reversible hydrogen electrode, RHE). Electrochemical impedance spectra and double layer capacitance showed that the enhanced oxygen evolution activities originated from the improved charge transfer capability and the increased electrochemically active interface between Co3O4 and ZnO. ZnO nanorods arrays serve as an effective scaffold for highly dispersed pulsed‐electrodeposited Co3O4. The increased electrochemically active area at the intimate interface between Co3O4 and ZnO accounts for the material's excellent performance in the oxygen evolution reaction. [ABSTRACT FROM AUTHOR]

The present study aims to investigate gas diffusion electrodes with ultra‐low platinum loading and increased durability, prepared by pulsed electrodeposition process, applicable for polymer electrolyte membrane fuel cells (PEMFC). Testing was performed both, in situ in a PEMFC test bench while prepared GDEs were compared to anodes and cathodes with commercially available catalysts by Johnson Matthey (JM), as well as ex situ regarding electrochemical properties and catalyst layer structure. High and stable performance of developed electrodes was achieved, while the Pt catalyst loading of investigated anodes and cathodes was reduced to 10 µgPt cm−2. The catalyst deposition was achieved via pulsed electrodeposition process from H2PtCl6‐containing electrolyte on an oxygen plasma‐pretreated corrosion‐stable carbon nanofiber (CNF) support. In situ performance tests show a similar operation behavior of the compared anodes, while activation losses of investigated cathodes are high due to the limited amount of catalyst material. However, Pt/CNF_c cathodes show significantly higher power densities than cathodes prepared with JM catalyst. Membrane electrode assemblies containing developed Pt/CNF_a anodes with 10 µgPt cm−2 reached a power density of 0.525 W cm−2 at a cell potential of 0.65 V, which was similar to anodes with commercially available HiSPEC 2000 catalysts by JM. Accelerated stress tests (AST) revealed that Pt/CNF_a anodes preserve their performance, whereas the commercial catalyst degraded severely. Cyclic voltammetry (CV) indicated a high electrochemical active surface area of Pt/CNF_a anodes. Moreover, the electrode characteristics, analyzed via electrochemical impedance spectroscopy after AST, showed marginal anode degradation. [ABSTRACT FROM AUTHOR]

Composite nickel coatings, were produced under direct (DC) and pulse current (PC) from a Watt's type bath, containing 0.5 g/L hybrid MWCNT-Al 2 O 3 , in presence and absence of additive Sodium Dodecyl Sulfate - SDS. Surface morphology, crystallographic orientation, wear resistance and corrosion resistance were studied. Micro-Raman measurements revealed that MWCNT-Al 2 O 3 particles are distributed at the whole depth of the cross-section profile analysis. The application of pulse current, favored a random crystallographic orientation of Ni crystallites with reduced grain sizes in comparison with pure Ni. The evaluation of the tribological data demonstrated that the composite coatings produced under pulse conditions in presence of additive, exhibited lower coefficient of friction, higher resistance to dry sliding accompanied by the presence of increased amounts of nickel oxide in wear tracks compared to pure Ni coatings. The behavior of pure and composite coatings in corrosive environment was evaluated by electrochemical impedance spectroscopy. It was found that composite coatings attained their corrosion resistance characteristics for 60 h in 0.6 M NaCl solution. Differences between pure nickel and composite coatings were attributed mainly to morphological differences rather than differences on corrosion performance. [ABSTRACT FROM AUTHOR]

Thin Ni-Fe films were produced via electrodeposition onto silicon substrate using direct current and pulse (with different pulse durations) regimes. The correlation between technological regimes and chemical composition and microstructure for Ni-Fe nanogranular films was discussed. Analysis of the microstructure evolution revealed the changing mechanism of the films growth from the Volmer-Weber (describes island film growth) to the Stranski-Krastanov (layer by layer at the growth beginning) with the shortening of the pulse duration less than 10 μs. This anomalous behavior was explained by an increase of the binding energy between the initial atoms and the substrate surface. The results showed that using electrodeposition regimes, which ensure growth with the average crystal size less than the critical value (10 nm), provides less roughness, defectiveness and greater film uniformity in thickness, and, therefore, stable properties. [ABSTRACT FROM AUTHOR]

This study reports an approach to achieving stable 2 and 3 Li + insertion, respectively, into vanadium pentoxide (V 2 O 5 ) as lithium-ion battery (LIB) cathode materials using a core-shell structure based on a self-standing carbon nanofiber (CNF) membrane fabricated by an electrospinning process. Uniform coaxial V 2 O 5 shells are coated onto continuous CNF cores via a pulsed electrodeposition. The materials analyses confirm that the V 2 O 5 shell after 4 h of thermal annealing at 300 °C forms a partially hydrated amorphous structure. SEM and TEM images indicate that the uniform 30–50 nm thick V 2 O 5 shell forms an intimate interface with the CNF core. Lithium insertion capacities up to 291 and 429 mAh g −1 are achieved in the voltage ranges of 4.0–2.0 V and 4.0–1.5 V, respectively, which are in good agreement with the theoretical values of 294 mAh g −1 for 2 Li + /V 2 O 5 insertion and 441 mAh g −1 for 3 Li + /V 2 O 5 insertion into crystalline V 2 O 5 materials. Moreover, after 100 cycles, remarkable retention rates of 97% and 70% are obtained for 2 Li + /V 2 O 5 and 3 Li + /V 2 O 5 insertion, respectively. These results reveal that it is potentially feasible to fabricate the core-shell structure with electrospinning and electrodeposition processes to break the intrinsic limits of V 2 O 5 and enabling this high-capacity cathode materials for future LIBs. [ABSTRACT FROM AUTHOR]

In this work, a 304 stainless steel (SS) was anodized to prepare nanoporous SS (NPSS) with an average size of about 75 nm and then filled with copper (Cu/NPSS) using pulsed electrodeposition method. Afterward, a nanostructural Pt and Pd film was deposited by galvanic replacement (GR) on the Cu/NPSS to prepare modified electrode (PtPd/Cu/NPSS) for hydrogen evolution reaction (HER) and formic acid electrooxidation (FAO). The electrocatalytic activity of the modified electrode and its structural characterization have been studied by voltammetric methods, electrochemical impedance spectroscopy (EIS), inductively coupled plasma optical emission spectrometry (ICP-OES), and field emission scanning electron microscopy (FESEM). The results show that the nanostructural Pt1Pd1/Cu/NPSS composition, with low Pt loading and suitable stability, has a good electrocatalytic performance toward HER (EOnset = + 12 mV vs. NHE) and FAO (EOnset = −180 mV vs. NHE). For HER observed a high mass activity of noble metals (87.54 mA cm−2μgPd+Pt−1) in comparison with Pt deposited Cu/NPSS (41.5 mA cm−2 μgPt−1) at the same applied potential of − 0.25 V versus NHE. Also, the fabricated electrocatalysts with more electrochemically active surface area in comparison with Pd/Cu/NPSS and Pt/Cu/NPSS revealed more resisting to the poisoning components and good stability for FAO. [ABSTRACT FROM AUTHOR]

Owing to the presence of large fraction of grain boundaries, deformation-induced grain growth is commonly observed in fine-grained electrodeposited metals. Here we demonstrate that microcrystalline copper (d∼1-10 µm) with different textures produced by electrodeposition exhibit significant deformation-induced grain growth in tension by coalescence along with twin boundary migration and detwinning. Oriented growth with the formation of a cube texture was noted in the deformed samples. There was an increased fraction of twin boundaries with large angular deviation from Brandon's criterion during deformation. [ABSTRACT FROM AUTHOR]

Toxic 4-Nitrophenol (4-NP) is a notable contaminant in industrial waste water, and intrusion of waste water into water sources make prominent lethal contamination. As, 4-Aminophenol (4-AP), the reduced product of 4-Nitrophenol, is an important intermediate in the production of numerous drugs. Palladium-nickel alloy is an effective catalyst for the reduction of 4-NP. In this work, Pd-Ni alloys with different atomic ratio was synthesized by the pulsed electrodeposition technique and its catalytic performance was tested. X-ray diffraction analysis confirms the fcc structure of Pd-Ni alloy with the crystallites size ranges from 17 to 21 nm. The interfacial electron transfer from Ni to Pd is revealed from X-ray photoelectron spectroscopy. High resolution scanning electron microscopy and transmission electron microscopy confirms the formation of dendrites structure. The magnetic behavior of the alloys was confirmed by Vibrating sample magnetometer (VSM) which reveals the ferromagnetic nature. The catalytic studies shows that Pd-Ni alloy have reduced the 4-NP with kinetic rate constant of 0.55 min −1 . The synergic effect of the Pd-Ni alloy exhibits the better catalytic activity than congruent individual metals. [ABSTRACT FROM AUTHOR]

We have studied the effect of thickness on the structural, microstructural, electrical and magnetic properties of Ni films electrodeposited onto -Si (100) substrates. A series of Ni films have been prepared for different potentials ranging from 1.6V to 2.6V. Rutherford backscattering spectrometry (RBS), X-ray diffraction (XRD), four point probe technique, atomic force microscopy (AFM) and vibrating sample magnetometry (VSM) have been used to investigate the physical properties of elaborated Ni thin films. From the analysis of RBS spectra, we have extracted the films thickness ( ranges from 83nm to 422nm). We found that the Ni thickness, (nm), linearly increases with the applied potential. The Ni thin films are polycrystalline and grow with the texture. The lattice parameter (Å) monotonously decreases with increasing thickness. However, a positive strain was noted indicating that all the samples are subjected to a tensile stress. The mean grain sizes (nm) and the strain decrease with increasing thickness. The electrical resistivity (cm) increases with for less than 328nm. The diffusion at the grain boundaries may be the important factor in the electrical resistivity. From AFM images, we have shown that the Ni surface roughness decreases with increasing thickness. The coercive field , the squareness factor , the saturation field and the effective anisotropy constant are investigated as a function of Ni thickness and grain sizes. The correlation between the magnetic and the structural properties is discussed. [ABSTRACT FROM AUTHOR]