Potentiodynamic Electrodeposition Research Articles

Improvement of chitosan solubility and bactericidity by synthesis of N-benzimidazole-O-acetyl-chitosan and its electrodeposition

Chitosan solubility and its antibacterial activity have been improved first of all with a chemical synthesis of N-benzimidazole-O-acetyl-chitosan in acetic medium and foremost through a potentiodynamic electrodeposition of this derivative. An association of one benzimidazole and three acetyl moieties per two units of the biopolymer chain was evidenced by FTIR and 1H NMR, pH-metric titration and TG analysis. Cyclic voltammetry study of the modified polymer in acetonitrile solution reveals its anodic oxidation at a platinum disk and a progressive growing of a thin film, through the cycling of potential. An enhancement of the solubility of the biopolymer as well as its antibacterial activity against Salmonella typhimurium, Escherichia coli, Staphylococcus aureus and Pseudomoenas aeruginosa bacteria have been observed with these chemical and after electrochemical modifications.

Gold Nanoparticles Sensitized ZnO Nanorods Arrays for Dopamine Electrochemical Sensing

One-dimensional nanostructure materials offer opportunities for improving performance of electrochemical sensors. In this work, vertically ZnO nanorods (ZNRs) sensitized with gold nanoparticles (GNPs) were designed and fabricated onto indium tin oxide coated polyethylene terephthalate (ITO/PET) film for dopamine sensing. ZNRs that helpful for electric signal collecting by providing electron transfer pathways were electrodeposited on ITO/PET film firstly. Then GNPs that possess excellent electrocatalytic activity toward target were decorated onto ZNRs via potentiodynamic electrodeposition. These gold nanoparticles sensitized ZnO nanorods arrays (GNPs/ZNRs) combine the advantages of GNPs and ZNRs, thus providing chance to develop electrochemical sensors with ultrahigh sensitivity and excellent selectivity. Several important nervous system diseases (such as Parkinson's disease, schizophrenia, senile dementia, AIDS, et al.) have proved to be associated with dysfunctions of dopamine system. So, the detection of dopamine becomes essential in clinical medical practice and nerve physiology study. When used for dopamine sensing, the fabricated electrochemical sensor shows two linear dynamic ranges (0.01–20 μM and 50–1000 μM) toward dopamine. Moreover, this proposed electrochemical sensor has been successfully applied to the determination of dopamine in human urine with satisfied recoveries (95.3% to 111.3%) and precision (1.1% to 8.4% of RSD).

The Art of Decoration: Rhodium-Modified Platinum Films with Preferential (100) Orientation as Electrocatalysts for Nitrate Reduction and Dimethyl Ether Oxidation

Nanostructured platinum films with a preferential (100) orientation were decorated with a rhodium adlayer through potentiodynamic electrodeposition. The Rh surface coverage was controlled by varying the number of electrodeposition cycles, and the growth of the Rh layer was followed by means of the distinct hydrogen adsorption/desorption peaks pertaining to Rh. The bimetallic electrodes were tested for their catalytic activity toward a set of electrochemical reactions of the carbon and nitrogen cycles (nitrate reduction, CO oxidation, and DME oxidation) in H2SO4. At the same time, these reactions provided further insight into the surface structure of the Rh deposits: thus, it was found that Rh deposition occurs mostly at (100) sites, creating ordered Rh islands. It was shown that DME oxidation at Pt(100) can be further promoted by minimum Rh coverages, at which the highly active (100) terraces remain mostly free. On the other hand, the activity toward nitrate reduction can be enhanced by increasing amounts...

Electrochemical Formation of p-Type Bi0.5Sb1.5Te3 Thick Films onto Nickel

Bismuth-telluride-based alloys are currently the best commercially available thermoelectric materials for applications at room temperatures. Up to 150 micron thick layers of bismuth antimony telluride (Bi0.5Sb1.5Te3) were directly deposited onto nickel by either potenstiostatic or potentiodynamic electrodeposition. Cyclic voltammetry was employed to identify the optimal deposition potential. The films were characterized by scanning electron microscopy, energy dispersive X-rays and X-ray diffraction. The p-type films were found to be well adherent, uniform and stoichiometric with a high power factor of 2.3 × 10−4 W m−1 K−2 at film growth rates of up to 40 μm h−1.

Facile Preparation and Enhanced Capacitance of the Ag-PEDOT:PSS/Polyaniline Nanofiber Network for Supercapacitors

This paper reports the synthesis of a silver − Poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate)/Polyaniline(Ag-PEDOT:PSS/PANI)hybrid nanostructure using a simple dip coating technique followed by potentiodynamic electrodeposition to achieve an electrochemical supercapacitor with excellent electrochemical performance. In this sandwich type structure, the Ag nanostructure-blended PEDOT: PSS acts as a current collector, where electrons can be transferred easily through this network to the PANI nanofibers and vice versa. The AgNW-PEDOT:PSS/PANI showed a specific capacitance of 643 Fg−1 at 10 mVs−1 and an energy density of 86.19 Whkg−1 at 0.1mA, indicating the positive synergistic effect of silver nanowires (AgNW), PEDOT:PSS and PANI. The Ag nanostructure incorporated PEDOT:PSS helps to improve the electronic conductivity and the electrochemical stability of the PANI electrodes. Promising electrochemical properties achieved from the measurement of symmetric device demonstrate the ideal capacitive behavior of our prepared electrodes.

Preparation of Ni–Co alloy coating on sintered NdFeB magnet by potentiodynamic electrodeposition

A protective Ni–Co alloy coating was successfully prepared on sintered neodymium–iron–boron (NdFeB) magnet via potentiodynamic electrodeposition in this paper. The microstructure and surface morphology analysis of Ni–Co alloy coating showed that the surface morphologies were quite compact and more uniform than that prepared by direct current (DC) electrodeposition; significantly, the chemical composition analysis indicated that the content of Co in the alloy coatings amounted to 33–34 wt-%. Potentiodynamic polarisation and long term immersion test results revealed that the Ni–Co alloy coating could supply excellent corrosion protection for NdFeB substrate in 3.5 wt-% NaCl solution. Overall, the Ni–Co alloy coating with higher Co content prepared by potentiodynamic electrodeposition exhibited better corrosion protection for sintered NdFeB magnet compared with that prepared by DC electrodeposition.

Potentiodynamic Uniform Anchoring of Platinum Nanoparticles on N‐Doped Graphene with Improved Mass Activity for the Electrooxidation of Ammonia

AbstractPlatinum nanoparticles anchored N‐doped graphene (Pt/NG) catalysts are synthesized using a thermal annealing–potentiodynamic electrodeposition approach with melamine, graphene oxide, and PtCl62− as precursors. SEM, TEM, XRD, and XPS measurements indicate the relatively uniform and good dispersal of Pt nanoparticles on NG nanosheets. Compared to control catalysts of Pt nanoparticles loaded onto glassy carbon, undoped graphene and g‐C3N4, the Pt/NG(1‐1) catalyst (with a nominal mass ratio of melamine/graphene oxide of 1:1) shows the highest electrocatalytic activity towards the oxidation of ammonia among a series of Pt/NG catalysts. The mass activity of Pt/NG(1‐1) catalyst is nearly 5.1 times as high as that of Pt/glassy carbon. The excellent electrochemical performance of Pt/NG catalysts is attributed mainly to the considerable extent of pyridinic N and graphitic N‐doping in the graphene network, which improves the dispersion state of Pt nanoparticles on the NG support, resulting in an apparent enhancement in mass activity.

Nanomorphology-dependent pseudocapacitive properties of NiO electrodes engineered through a controlled potentiodynamic electrodeposition process

Three nickel oxide (NiO) electrodes of different nanostructures have been successfully engineered through a controlled potentiodynamic electrodeposition process, which show a noticeable effect on pseudocapacitive properties of NiO electrodes.

Design and electro-synthesis of 3-D nanofibers of MnO2 thin films and their application in high performance supercapacitor

This paper highlights suitability of three dimensional (3D) network composed of manganese oxide nanofibers (NF-MnO2), synthesized by the potentiodynamic electrodeposition for supercapacitor application. Electrodeposition mechanism of manganese oxide is discussed with the help of electrochemical quartz crystal microbalance (EQCM) study and it reveals that maximum mass deposited on the electrode surface occurs at 0.85V vs SCE. The FE-SEM images exhibit an interconnected 3-D network composed of MnO2 nanofibers with diameter varies from 10 to 27nm and length of the order of 0.1 to 0.5μm, exhibiting high aspect ratio. XPS measurements revealed that the peak appeared at binding energies of 642.6 and 654.05eV attributed to the Mn4+ state in the NF-MnO2. The maximum specific capacitance of ∼392F.g−1 at 10mV.s−1 by using cyclic voltammetry (CV) and 383F.g−1 at a current density of 2mA.cm−2 by charge discharge studies were achieved for the NF-MnO2 in an electrolyte of 1M Na2SO4. The NF-MnO2 exhibits an excellent rate capability with high specific energy of ∼48.74 Wh.kg−1 and specific power of ∼2.12kW.kg−1. The high specific capacitance and charge–discharge rates offered by NF-MnO2 make them promising candidates for supercapacitor electrodes, combining high-energy densities with high levels of power delivery.

Electrochemical performance of potentiodynamically deposited polyaniline electrodes in ionic liquid

Present work reports electropolymerization of aniline onto stainless steel substrate using room temperature ionic liquid N-methyl-2-pyrrolidonium hydrogensulfate [NMP][HSO4] by potentiodynamic electrodeposition method. To study the effect of electropolymerization cycle number on the electrochemical performance, the number of scans is varied from 1st to 5th cycle. X-ray photoelectron spectroscopy is used for the phase identification of polyaniline (PANI) films. Scanning electrochemical microscopy (SECM) was used to study the electrochemical activity of PANI films. The highest specific capacitance of 581 Fg−1 and energy density of 96.6 whkg−1 are obtained for the sample, deposited using four cycle.

Monitoring of Silver Electrodeposition onto HOPG Electrodes in the Presence of Picolinic Acid by in Situ Surface-Enhanced Raman Spectra Measurements

In situ surface-enhanced Raman spectra (SERS) have been recorded during silver potentiodynamic electrodeposition onto HOPG electrodes from solutions containing silver perchlorate and picolinic acid (PA). Modification of the composition and pH of the electrolyte has allowed us to achieve an adequate control of the electroactive species distribution in solution. The adsorption behavior of different PA species on silver growing crystallites has been studied by using the potential dependence of SERS signals. Analysis of the vibrational bands from additive molecules has allowed us to establish that at pH > 3.0 the PA anion is the most stable species on the electrode surface, whereas the predominant species in solution is the zwitterion. At pH 0.3, adsorption of zwitterion and anion species onto the silver surface, even though the PA cation is predominant in the solution, has been evidenced. For all the SERS spectra it was possible to infer the adsorption geometry and the ClO4– ion coadsorption. Detection of in...

Carbon nanotube-assisted electrodeposition. Part I: Battery performance of manganese oxide films electrodeposited at low current densities

In electrochemical synthesis of manganese oxide, current density has a substantial influence on redox behavior, but less effect on the film morphology. Here we report that a small amount (even not detectable by electron microscopy) of carbon nanotubes can significantly affect the film growth pathway. Although, the galvanostatic syntheses of manganese oxide were similar in the absence and presence of carbon nanotubes, the morphological structures are totally different. This difference is also valid for electrochemical behavior in favor of the formation of a single redox couple. The influence of carbon nanotubes on potentiodynamic electrodeposition of manganese oxide was also similar, leading to the appearance of a strong redox couple without any noticeable capacitive behavior. It should be emphasized that this influence is only valid for the experimental condition under consideration (i.e., low current densities), and electrodeposition at higher current densities in the presence of carbon nanotubes may strengthen the capacitive behavior in favor of supercapacitors (as discussed in the second part). The interesting point is that this tiny additive can predominantly control the electrochemical properties of the system under consideration: supercapacitor or battery.

Potentiodynamically deposited nickel oxide (NiO) nanoflakes for pseudocapacitors

The present work demonstrates the preparation of NiO nanoflakes via potentiodynamic electrodeposition method. The structural and morphological analyses of the film have been presented. The pseudocapacitive properties are tested using cyclic voltammetry, charge–discharge and electrochemical impedance spectroscopy. The maximum value of specific capacitance obtained is 222Fg−1.

Supercapacitive activities of potentiodynamically deposited nanoflakes of cobalt oxide (Co3O4) thin film electrode

In the present work, the Co3O4 thin films are successfully prepared via potentiodynamic electrodeposition method onto inexpensive stainless steel substrate. As-deposited films were heat treated at 623K for their conversion into Co3O4. These films were characterized by means of X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and scanning electron microscopy (SEM) techniques. The X-ray diffraction (XRD) study revealed the formation of cobalt oxide (Co3O4) with cubic crystal structure. The FT-IR study supports the formation of Co3O4 material. The SEM image of Co3O4 film showed nanoflake-like morphology with an average thickness of 100nm. Supercapacitive properties of Co3O4 thin film electrode were examined using cyclic voltammetry and charge–discharge techniques. The Co3O4 thin film electrode showed maximum specific capacitance of 365Fg−1 in 1M KOH electrolyte at the scan rate of 5mVs−1. The charge–discharge technique was employed to estimate the values of specific energy, power and coulombic efficiency as 64Whkg−1, 21.53kWkg−1 and 99%, respectively.

Performance evaluation of symmetric supercapacitor based on cobalt hydroxide [Co(OH)2] thin film electrodes

In the present investigation, we have successfully assembled symmetric supercapacitor device based on cobalt hydroxide [Co(OH)2] thin film electrodes using 1M KOH as an electrolyte. Initially, potentiodynamic electrodeposition method is employed for the preparation of Co(OH)2 thin films onto stainless steel substrate. These films are characterized for structural and morphological elucidations using X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. The XRD reveals formation of β-Co(OH)2 material with hexagonal crystal structure. The SEM images show formation of nanoflakes like microstructure with average flake width 100nm. Electrochemical characterizations of Co(OH)2 based symmetric supercapacitor cell are carried out using cyclic voltammetry, charge–discharge and electrochemical impedance spectroscopy (EIS) techniques. In the performance evaluation the maximum values of specific capacitance, specific energy and specific power are encountered as 44Fg−1, 3.96Whkg−1 and 42kWkg−1. The value of equivalent series resistance (ESR) is estimated as 2.3Ω using EIS.

Electrodeposition of Sb x Te y Thermoelectric Films from Dimethyl Sulfoxide Solution

The electrochemical behaviors of nonaqueous dimethyl sulfoxide solutions containing TeIV and SbIII were investigated using cyclic voltammetry. On this basis, SbxTey thermoelectric films were prepared by the potentiodynamic electrodeposition technique from nonaqueous dimethyl sulfoxide solution, and the composition, morphology, and thermoelectric properties of the films were analyzed. SbxTey thermoelectric films prepared under different potential ranges all possessed smooth morphology. After annealing treatment at 200°C under N2 protection for 4 h, all the deposited films showed p-type semiconductor properties. Sb1.87Te3.13 thermoelectric film, which most closely approached the stoichiometry of Sb2Te3 and possessed the highest Seebeck coefficient, could be potentiodynamically electrodeposited in the potential range of −200 mV to −600 mV.

Electrodeposited Polyaniline in a Nanoporous WO3 Matrix: An Organic/Inorganic Hybrid Exhibiting Both p- and n-Type Photoelectrochemical Activity

This study focuses on the electrodeposition of a conducting polymer such as polyaniline (PANI) into a tungsten trioxide nanoporous host framework. Nanoporous WO3 films were initially electrosynthesized on tungsten foil by anodization at different voltages in a fluoride-containing medium. The PANI layer was electrografted onto the entire surface of the WO3 using potentiodynamic electrodeposition in sulfuric acid electrolyte. The morphological features of oligomer/polymer formed in the nanoporous oxide template were monitored by field-emission scanning electron microscopy. Systematic changes in the morphology afforded insights into the evolution of the WO3/PANI hybrid assembly. This assembly was subsequently characterized by Raman spectroscopy, X-ray photoelectron spectroscopy, cyclic voltammetry, and photoelectrochemical measurements. Photovoltammetric data indicated the complex behavior of the hybrid, featuring the properties of both of its components: namely, p-type behavior in the cathodic polarization ...

Electrochemical behavior of potentiodynamically deposited cobalt oxyhydroxide (CoOOH) thin films for supercapacitor application

In the present study, we report, for the first time, the synthesis of cobalt oxyhydroxide thin films on inexpensive stainless steel substrate using potentiodynamic electrodeposition method. These films were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM) techniques. The orthorhombic crystal structure was revealed by the X-ray diffraction study. The FT-IR spectrum confirmed the formation of cobalt oxyhydroxide. The SEM studies showed the nanoflakes-like morphology with an average thickness of 100nm. The cyclic voltammetry study of the cobalt oxyhydroxide films in 1M KOH showed maximum specific capacitance of 449Fg−1 at scan rate of 5mVs−1.

Diffusion‐Controlled Solid‐State Formation of CoSb Phase from Co/Sb‐Multilayered Nanowires

The physical properties of materials on a nanometer scale are known to be different from those of bulk form due to dimensional confinement effects and high specific surface‐to‐volume ratio. In this study, the size effects on the diffusion and reaction at the interface of dissimilar nanowires (NWs) were investigated. Co/Sb‐multilayered NWs of 15 ± 1 and 19 ± 2 nm in radius have been grown within anodic aluminum oxide templates using a pulsed potentiodynamic electrodeposition method. XRD and TEM results demonstrated that the multilayered NWs were transformed to a CoSb phase through a solid‐state reaction at the temperature in the range of 653 to 693 K. The kinetics of the solid‐state reaction was analyzed and found to be diffusion controlled at the interface between Co and Sb phases. The reaction was controlled by the dominant diffusion of Sb atoms. The activation energies for the solid‐state reaction were estimated to be 0.9 and 0.7 eV/atom for the multilayered NWs with radii of 15 and 19 nm, respectively.

Polymerisation of methyl ethyl ketone formaldehyde resin modified with carbazole‐9‐carbonyl chloride

Purpose – The purpose of this paper is to obtain a conductive polymer by using a fluorescence comonomer which is an insulator. In this study, methyl ethyl ketone formaldehyde resin (MEKFR) modified with carbazole‐9‐carbonyl chloride (CzCl) was synthesised via hydroxyl groups of MEKFR. Electrochemical polymerisation of Cz‐MEKFR comonomer was carried out potentiostatically and a green, conductive polymer P(Cz‐MEKFR) was obtained. The advantages of obtaining alternative structure of P(Cz‐MEKFR) to the random copolymer were reported.Design/methodology/approach – Cz‐MEKFR comonomer was synthesised by the esterification reaction of CzCl and hydroxyl groups of MEKFR. Then, for the electrochemical polymerisation, potentiodynamic electrodeposition of Cz‐MEKFR comonomer in dichloromethane on to Pt was carried out. Electrochemical activities of polymers were tested by electrochemical methods (i.e. polarization curves and cyclovoltammetry). UV‐visible, NMR, polarization curves, cyclovoltammetric, solid‐state conducti...