Deposition Potential Range Research Articles

A Cathodic Electrochromic Material Based on Thick Perylene Bisimide Film with High Optical Contrast and High Stability

A Cathodic Electrochromic Material Based on Thick Perylene Bisimide Film with High Optical Contrast and High Stability

Influence of pH of the electrolyte on the formation and properties of electrodeposited ZrSe2 thin films

Zirconium diselenide thin films were electrodeposited on the stainless steel substrates for various pH values ranging from 2.0 to 3.5. The deposition potential range suitable for the deposition has been optimized using cyclic voltammetry (CV). The X-Ray Diffraction (XRD) results confirm that the thin films produced were polycrystalline in nature with hexagonal structure peak at 2θ = 43.8° (003) of ZrSe2. The surface morphology of the film indicate, as the pH was increased the grain size of the film become larger due to agglomeration. The direct band gap energy of the films was found to be in the range of 1.77–1.83 eV.

Electrodeposition of nanostructured cobalt films from a deep eutectic solvent: Influence of the substrate and deposition potential range

The purpose of this systematic study was to investigate the effects of specific substrates and potential conditions applied while tailoring the morphology and chemical composition of nanostructured Co films. In particular, Co electrodeposition in sustainable choline chloride-urea deep eutectic solvent was assessed, using glassy carbon and two metals widely employed in electrocatalysis and biocompatible purposes, Pt and Au, as substrates for modification with Co. Various in situ electrochemical techniques were combined with a broad range of ex-situ characterization and chemical-composition techniques for a detailed analysis of the prepared Co films. Among the results, nanostructured Co films with high extended active surface areas and variable composition of oxo and hydroxyl species could be tuned by simply modulating the applied potential limits, and without using additives or surfactant agents. The study highlights the effectiveness of using deep eutectic solvent as suitable electrolyte for surface modification by controlled deposition of nanostructured Co films with further application in electrocatalysis.

Polypyrrole coatings on rheocast aluminum‐silicon alloy: A correlation between properties and electrodeposition conditions

The effect of the electrolyte composition and the deposition potential range on the physical properties and possible corrosion protection effect of polypyrrole coatings on rheocast aluminum–2.5 % silicon alloy is investigated. Solutions with different concentrations of sodium nitrate and an electron transfer mediator reagent were used for the electrodeposition. Polypyrrole coating is able to hinder the entrance of electrolyte. Upon the penetration of chloride ions, the coating can induce passivation of the alloy's surface by its reduction. The thickness of the coating and its ion‐barrier properties, controlled by the electrodeposition conditions, are shown as the important factors influencing the protection efficiency. However, localized drastic galvanic coupling at the polypyrrole/aluminum interface forms blisters, causes failure, and limits the possible protection.

Electrodeposition of manganese layers from sustainable sulfate based electrolytes

Functional manganese-(Mn)-containing layers are becoming increasingly important in the fields of sacrificial corrosion protection, biodegradable medical devices or electrochemical energy conversion systems. Electrodeposition can be a low cost and time-efficient production route, but the very electronegative nature of Mn makes this reduction process quite challenging.In this paper, electrolytic potentiostatic deposition of metallic Mn layers from environmentally friendly aqueous manganese sulfate electrolytes with pH3 is successfully demonstrated. A continuous electrolyte flow in the cathodic compartment of the electrochemical cell for controlling the pH value during deposition was found to be essential for achieving good layer qualities. Based on cyclic voltammetry analysis in combination with quartz crystal microbalance measurements a suitable deposition potential range was identified. The obtained electrodeposited layers were characterized by means of SEM, XRD, GD-OES and XPS. The shift of the deposition potential from −2.4 VMSE to −2.6 VMSE (deposition time 60min) yields a thickness increase of the metallic α-Mn deposits from <500nm to ~2μm. Only thin additional surface regions of Mn-oxides/-hydroxides were identified. The important role of (NH4)2SO4 as complex-forming electrolyte additive is discussed and an impact of the salt concentration on the deposit properties is revealed. This is a promising starting point for further Mn alloy deposition analysis.

Morphological control and characterization of CdTe microstructure arrays synthesized by one-step electrodeposition

Without templates and any addition of surfactants, cadmium telluride (CdTe) microstructures with various novel morphologies were fabricated by one-step electrodeposition in the acid system during the deposition potential range from −0.65V to −0.50V (vs. Ag/AgCl). The structures and properties of the as-synthesized films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), UV–vis absorption spectroscopy and photoelectrochemical measurements. XRD pattern revealed that the high-purity CdTe films were cubic phase and exhibited the preferential orientation along (111) direction. The SEM indicated that by varying the deposition potential, we can obtain CdTe structure arrays with different morphologies evolution from microrod arrays to highly ordered flower-like structures. In addition, based on the better optical and photoelectrochemical performances, these CdTe microstructures would be potentially applied for substrate configuration photovoltaic device applications.

Deposition Potential Influence on the Electrodeposition of Zn–Ni–Mn Alloy

The effect of deposition potential on the electrodeposition, composition, surface characteristics and corrosion resistance properties of Zn–Ni–Mn alloy coatings were investigated. During the deposition potential range from −0.500 to −1.000 V, normal codeposition of the alloy components occurred, meanwhile at deposition potentials more cathodic than −1.000 V, the anomalous codeposition took place. Shifting the deposition potentials toward the negative direction led to an increase in the thickness of the deposit, incremented the adhesion and compactness and improved the corrosion resistance properties. X-ray diffraction studies of the deposit showed the presence of hexagonal pure Zn phase, hexagonal Mn0.27Zn0.73 phase and cubic γ-Ni5Zn21 and/or tetragonal δ-Ni3Zn22 phases.

Preparation of pseudocapacitor electrodes via electrodeposition of polyaniline on nonwoven carbon fiber fabrics

ABSTRACTAniline has been polymerized via electrodeposition onto various nonwoven carbon fiber fabric (CFF) substrates for use as a pseudocapacitive electrochemical capacitor. Four types of CFF were initially tested for double layer capacitance before polyaniline deposition, and again for specific capacitance after deposition. A binder‐free CFF was selected for further analysis due to its high capacitance change following PANI deposition (three orders of magnitude). The aniline monomer concentration, deposition potential, and deposition time were varied and resulting materials were characterized using chrono‐potentiometry, cyclic voltammetry, and scanning electron microscopy. The deposition potential range yielding highest capacitance was found to be between 0.744 and 0.777 V. A solution concentration of 0.5M aniline at a 20 min deposition time resulted in the highest specific capacitance (&gt;80 F/g based on total electrode mass and &gt;300 F/g based on PANI mass) within this study. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43315.

Electrodeposition and Characterization of Copper Oxide Thin Films for Solar cell Applications

Copper oxide thin films are being considered in thin film solar cells for its unique photovoltaic properties. Electrodeposition is one of the cheapest processes to deposit copper oxide thin films. In this study, copper oxide was electrodeposited on the copper substrate and gold plated glass substrate in an electrolyte bath containing 0.2M CuSO4.5H2O, 3M lactic acid and NaOH. A Potentiostat/Galvanostat with silver chloride electrode (Ag/AgCl) as a reference electrode was used for elctrodeposition. During deposition, the bath temperature and pH were maintained 600C and 12-12.5 respectively. Copper oxide was deposited at different potentials and deposition time. The films deposited at different electrodeposition conditions were characterized by Scanning Electron Microscopy (SEM) and Energy-dispersive X-ray spectroscopy (EDS). The optical band gap was determined from the films deposited on gold plated glass substrate using Ultraviolet-Visible Spectroscopy. From visual inspection it was found that copper oxide film was black and adherent on copper substrate. In gold coated glass substrate copper oxide film was also black but bonding between the substrate and copper oxide film was not good. The SEM study reveal that the films become more compact and grain sizes of copper oxide films decreases at more negative potentials in deposition potential range. EDS analysis shows that percentage of oxygen in the copper oxide films increases with more negative potentials at the deposition potential range. It was found that with increase of time more adherent and uniform film thickness occurs. The variation of the thickness of copper oxide films with different deposition parameters was analyzed.

Electrochemically decorated ZnTe nanodots on single-walled carbon nanotubes for room-temperature NO2 sensor application.

A gas sensor with ZnTe nanodot-modified single-walled carbon nanotubes (SWCNTs) is demonstrated for NO2 detection at room temperature. ZnTe nanodots are electrochemically deposited in an aqueous solution containing ZnSO4, TeO2 and citrate. A deposition potential range of ZnTe formation of -0.65 to -0.9 V is determined by cyclic voltammetry, and an intermetallic ZnTe compound is formed at above 50 degrees C bath. SWCNT-based sensors show the highly sensitive response down to 1 ppm NO2 gas at room temperature. In particular, the sensitivity of ZnTe nanodot-modified SWCNTs is increased by 6 times as compared to that of pristine SWCNT sensors. A selectivity test of SWCNT-ZnTe nanodots sensors is carried out with ammonia gas (NH3) and methanol vapor (MeOH), and the result confirms an excellent selectivity to NO2 gas.

Structural, Optical and Electrical Properties of Electrodeposited Sb-Doped ZnO Nanorod Arrays

Sb-doped ZnO nanorod arrays were fabricated using electrochemical solution method with suitable combination of Zn(NO3)2, hexamine and SbCl3. Cyclic voltammetry was performed to determine the suitable deposition potential range. The influences of various growth parameters on the structural and optical properties of Sb-doped ZnO nanorods were studied in detail. The applied potential was found to have a great effect on the shape, the crystalline quality and the Sb doping level of the Sb-doped ZnO nanorod. Both the increase of the Zn(NO3)2 concentration and the addition of SbCl3 were found to promote the nucleation of Sb-doped ZnO. But the addition of SbCl3 can also retard subsequent nanorod growth and thus influence the nanorod diameter. To achieve the highly-textured Sb-doped ZnO nanorod arrays with a high Sb doping level, high pH values should be avoided and the substrate with an Al-doped ZnO top layer is a good choice. Based on the above investigation, the growth mechanism of the Sb-doped ZnO nanorod was also discussed. Lastly, but most importantly, these Sb-doped ZnO nanorods were proved possessing p-type conductivity.

Fabrication and characterisation of high performance polypyrrole modified microarray sensor for ascorbic acid determination

In this study, gold microelectrode array (Au/MEA) with electrode of 12μm diameter was fabricated by photolithography technique. Subsequently, polypyrrole (Ppy) modified gold microarrays sensor (Ppy/Au/MEA) was prepared by cyclic voltammetry technique. The deposition potential range and number of cycles were optimised in order to get optimum thickness of Ppy film. Scanning Electron Microscope and Atomic Force Microscope investigations reveal that Ppy coating formed at 3 cycles is porous with thickness of 1.5μm which exhibiting high catalytic current for ascorbic acid (AA) in square wave technique (SWV). In contrast to earlier sensors designs, these Ppy/Au/MEA sensors exhibits lower detection limit (LOD) of 10nm towards AA at physiological conditions. It also exhibits enhanced sensitivity (2.5mAcm−2mM−1) and long range of linear detection limit from 10nm to 2.8mM. In the same way, polypyrrole modified macro Au (Ppy/Au/MA) biosensor was also fabricated and its electro catalytic property towards AA was compared with that of Ppy/Au/MEA. The Ppy/Au/MA exhibits sensitivity of only 0.27mAcm−2mM−1, LOD of 5μM and linear range of 10μM to 2.2mM. Hence, our investigations indicate that the Ppy/Au/MEA could serve as highly sensitive sensor for AA than any of the earlier designs. So, the Ppy/Au/MEA electrode was utilised for determination AA in a wide variety of real samples.

Template-Assisted Electrochemical Growth of Hydrous Ruthenium Oxide Nanotubes

We demonstrate that ruthenium oxide () nanotubes with controlled dimensions can be synthesized using facile electrochemical means and anodic aluminum oxide (AAO) templates. nanotubes were formed using a cyclic voltammetric deposition technique and an aqueous plating solution composed of . Linear sweep voltammetry (LSV) was used to determine the effective electrochemical oxidation potential of to . The length and wall thickness of nanotubes can be adjusted by varying the range and cycles of the electrochemical cyclic voltammetric potentials. Thick-walled nanotubes were obtained using a wide electrochemical potential range (-0.2~1 V). In contrast, an electrochemical deposition potential range from 0.8 to 1 V produced thin-walled and longer nanotubes in an identical number of cycles. The dependence of wall thickness and length of nanotubes on the range of cyclic voltammetric electrochemical potentials was attributed to the distinct ionic diffusion times. This significantly improves the ratio of surface area to mass of materials synthesized using AAO templates. Furthermore, this study is directive to the controlled synthesis of other metal oxide nanotubes using a similar strategy.

Electrodeposition of Pd nanowires and nanorods on carbon nanoparticles

We report on the method for synthesizing palladium nanowires and nanorods involving the electrodeposition on oxidized amorphous carbon nanoparticles from chloride containing solutions. The effect of the deposition overpotential and the concentration of palladium ions on the morphology of the Pd electrodeposits have been established. Palladium grows predominately in the shape of nanowires if electrodeposited at potentials in the H underpotential deposition potential (UPD) range, where chloride ions are adsorbed only at the edges of nucleated monolayer-thick clusters on the carbon surface. The effect of the concentration of palladium ions on deposits’ morphology is also discussed. The mechanism of electrodeposition of Pd nanowires and nanorods in the H UPD potential range has been proposed.

Characterization of Iron Sulfide Species in Model Solutions by Cyclic Voltammetry. Revisiting an Old Problem

AbstractA long‐standing problem associated with voltammetric determination of iron and sulfide in reduced natural waters has been the nature of the presumed analyte responsible for a reduction peak at −1.1 V vs. Ag/AgCl. Cyclic voltammetry at the Hg electrode is used here to study solutions with different Fe(II) to sulfide ratios in chloride and acetate electrolytes (pH 6–7). The results indicate that the −1.1 V peak can be assigned to reduction of Fe2+ or its labile complexes on FeS layers that partially cover the Hg electrode. Hg electrodes covered with FeS act like FeS solid electrodes over a very wide potential range (−0.35 to −1.9 V). Two mechanisms for forming FeS layers on Hg are described. Over the broadest deposition potential range, the dominant mechanism involves attachment at the Hg surface of FeS nanoparticles, which are generated quickly in initially supersaturated mixtures of Fe(II) and S(–II). In a narrow deposition potential range, roughly −0.56 to −0.70, FeS layers are produced additionally by replacement of preformed HgS. Because Fe2+ is reduced at −1.1 V on FeS layers and at −1.4 V on bare Hg, it may be underdetermined when only the −1.4 V peak is measured.

Electrodeposition of Ni/Cu Multilayers Nanowires Using Alumina Template

Nickel/copper multilayer nanowires have been electrodeposited in sulphamate electrolytes containing nickel and copper ions by alternating potential pulses using alumina template. In order to compare the wires and bulk behavior, nano-thick Ni/Cu multilayers bulk were electrodeposited on sputtered gold silicon under the same conditions. The optimal deposition potential range for nickel was between -1.2 and -1.25 V vs. a saturated calomel electrode (SCE) to minimize the copper content and to prevent formation of nickel hydroxide and nickel hydride. The optimal deposition potential range for copper was between -0.4 and -0.8 V vs. SCE. Magnetic properties of Ni/Cu multilayers were determined at various Ni and Cu layer spacing.

Cathodic Deposition of ZnSe on Copper Substrates

In this work, ZnSe thin films were cathodically electrodeposited on copper (Cu) substrates from aqueous solutions of ZnSO4 and SeO2 using a three electrode configuration. Cyclic voltampèrometry has been applied to determine the deposition potential range. The deposited films were composed of polycrystalline cubic ZnSe (111) and elemental selenium. The highest zinc content was observed on films deposited at E=−0.6 V vs SCE. The Zn:Se atomic percentage obtained by EDAX approached 1:1 after annealing at 250oC for 30 min. The films were found to have 44 nm lowest surface roughness and 15% highest reflectance. The results of this study suggest that the electrodeposited ZnSe films are suitable for applications in photovoltaic technology.

Electrochemical capacitors based on electrodeposited ruthenium oxide on nanofibresubstrates

Electrodeposition of RuO2 on electrospun TiO2 nanorods using cyclic voltammetry is shown to increase the capacitance ofRuO2. This phenomenon can be attributed to the large surface areas of the nanorods. Amongseveral ranges of deposition, the range from 0.25 to 1.45 V with respect to Ag/AgCl waseffective. The electrode deposited with this range exhibited a specific capacitance of534 F g−1 after deposition for 10 cycles with a scan rate of50 mV s−1. The structuralwater content in RuO2 was quite different depending on the deposition potential range. Higher amounts ofstructural water increased the charge storage capability. The stability of the electrode wastested using cyclic voltammetry over 300 cycles.

Electronic states and local structures of Cu ions in electrodeposited thin films of Cu and Cu2O from X‐ray absorption spectra

AbstractX‐ray absorption spectra near Cu K edges have been obtained for Cu and Cu2O thin films potentiostatically electrodeposited in an acetate bath. The electronic states of Cu ions and the local structures around these ions are studied using X‐ray absorption near‐edge structure (XANES) and extended X‐ray absorption fine structure (EXAFS) spectroscopy, respectively. The inner strains in micro‐size crystals of the electrodeposited Cu thin film are less than those of a commercial Cu foil. The partial electronic states of Cu ions near the Fermi level (E F) and the local structure around these ions show a systematic transformation from a Cu2O single phase (Phase I), to a Cu2O–Cu intermediate phase (Phase II) and a Cu single phase (Phase III) in thin films electrodeposited on titanium substrates for the deposition potential range of –100 to –900 mV. Phase II consists of independent Cu2O‐like and Cu‐like local structures, but not a Cu2O–Cu complex. Phase II is also characterized by a transition region from the semiconductor Cu2O to the metal Cu for the Cu electronic state having a p‐like character near the Fermi level in the oxygen O‐2p conduction band. (© 2006 WILEY‐VCH Verlag GmbH &amp; Co. KGaA, Weinheim)

Structural and annealing studies of potentiostatically deposited Cu2O thin films

Cuprous oxide (Cu2O) thin films were deposited on Cu and tin oxide coated glass substrates through potentiostatic electrodeposition. The optimum range of deposition parameters was experimentally investigated. X-ray diffraction studies revealed the formation of single-phase cubic Cu2O films in the deposition potential range from −0.355 to −0.555 V versus SCE. Studies revealed that an optimum pH of 9.0 yielded single-phase cubic films with improved crystallinity. The preferential orientation of (2 0 0) cubic Cu2O peak was found to increase with bath temperature in the range 30–70 °C. The effects of annealing on the preferred orientation, grain size and optical band gap were studied. The energy conversion efficiencies of as-deposited and annealed p-Cu2O films as photocathodes in photoelectrochemical (PEC) solar cells were studied and the results were discussed.