Papers by Keyword: Electrochemical Deposition

Abstract: The article considers the possibility of controlling the macromolecular structure of ternary alloys in the form of compact coatings, which are obtained by electrochemical means. This method of obtaining metal clusters is more economical than from plasma one. The influence of the cluster structure of the synthesized coatings in the form of a triple alloy of polyligand complex electrolytes on their functional properties is shown. There are presented the results of testing coatings from this ternary alloy of different elemental and cluster composition for microhardness according to Vickers. The highest microhardness was obtained by the coating with the lowest molecular weight of the cluster, which provided a denser packing of atoms.

Abstract: The paper considers the dependence of the continuity of the sol-gel coating of carbon fiber on the preliminary anodic oxidation of the surface in a sodium hydroxide solution. The effect of the treatment time, the voltage between the cathode and the anode, NaOH concentration in the electrolyte, and the temperature of the electrolyte was investigated. It is shown that with an increase in NaOH concentration in the electrolyte, the area of uncoated fiber surface sections increases, the continuity of the coating decreases, while the coating obtained without preliminary surface treatment has sufficient continuity of at least 93%. Changes in other parameters (temperature, time, voltage) of preliminary electrochemical surface treatment in the ranges under study did not allow us to fix regularities other than the given one.

Abstract: Mn₃O₄ nanosheets were deposited electrochemically on graphene modified carbon cloth (G–CC). The graphene layer improved significantly the hydrophilic property of carbon cloth and its compatibility with active materials, as a result, lower resistance and better structural stability were obtained for Mn₃O₄/G–CC compared with those for the electrode based on neat carbon cloth. Furthermore, the Mn₃O₄/G–CC possessed a capacitance of 1335 mF cm^–2 at a current density of 2 mA cm⁻², and a capacitance retention of up to 88 % after 2000 cycles at 10 mA cm^–2. It is believed that manganese oxide was anchored strongly on graphene layer through C–O–metal bonds, and the graphene layer on the surface of the CC could serve as elastic buffering layers to release the strain within manganese oxide, resulting the remarkable improvements in electrochemical performance. These excellent characteristics make this kind of the composites promising candidates as high performance electrodes for supercapacitor.

Abstract: Graphene Oxide (GO) is two dimensional material that has been widely studied as an electrode material for supercapasitor. We prepared thin films of GO on metal oxide substrate of indium tin oxide (ITO) and metal substrate of Copper (Cu) using electrochemical deposition technique from 0.5 mg/ml GO dispersed in water. ITO-GO film was prepared using voltage range of -1.6 V to 0 V (ITO) and Cu-GO film was prepared using voltage range of 0 V to 1 V at scan rate of 50 mV/s. Both samples were characterized using Cyclic Voltammetry (CV) measurements in 1 M KCl electrolyte at varied scan speed with platinum (Pt) as counter electrode and Ag/AgCl as reference electrode. We compare energy storage characteristics of ITO-GO and Cu-GO using cyclic voltammogram data. It is found that GO deposited in metal substrate of Cu has higer energy density compare to that deposited in metal oxide substrate of ITO.

Abstract: Graphene oxide (GO) layer has been successfully deposited on to ITO/TiO₂ substrate by electrochemical deposition. Deposition process of GO layers were carried out in one, three, and six cycles in the voltage range of-1.6 to 0 volt and scan rate of 50 mV/s. The variation of cycles was performed, in order to study the deposition process relates to device performances. TiO₂ macro-channel (TiO₂μc) also introduced in photoanode system and it required annealing treatment up to 500°C. The oxygen content in GO will be reduced by annealing treatment and the reduced-GO (rGO) layer was trapped inside of TiO₂ mesoporous. The cyclic voltammetry curves of blank sample and GO deposition were also observed in order to ensure the GO deposition process was successfully done. After immersing in ruthenium dye overnight, the ITO/TiO₂/rGO/TiO₂-μc was sandwiched with Pt/FTO as counter electrode to configure dye sensitized solar cell (DSSC) structure. The photovoltaic characteristics, morphology, and UV-Vis absorbance of each layer were investigated. A highest DSSC efficiency (η= 3.34 %) was achieved by 3-cycles of GO deposition process of photoanode with photocurrent density (J_sc) of 9.94 mA/cm², open voltage (V_oc) of 0.70 V and fill factor (FF) of 48.69% under 100 mW/cm² of light irradiation.

Abstract: Polyaniline has been widely developed for many applications, e.g. sensor, supercapacitor components, electrochromic devices, and anticorrosion pigments. Although the addition of polyaniline pigment in organic coatings has been an alternative for corrosion protection in industrial applications, the protection mechanism is still not fully understood. Herein in this study, as a part of the development of polyaniline/silicon dioxide coating for geothermal application, polyaniline has been deposited electrochemically on carbon steel surface in oxalic acid medium and tested in geothermal solution to understand the contribution of polyaniline to the corrosion protection of a polyaniline-based composite in the geothermal system. To observe the surface/interface reaction between the electrolyte and electrode surface during the electrochemical polymerization, electrochemical impedance spectroscopy (EIS) was applied after each cycle. For corrosion study in the geothermal application, an artificial geothermal solution was used with the composition of 1,500 mg/l Cl^-, 20 mg/l SO₄^2-, 15 mg/l HCO₃^-, 200 mg/l Ca²⁺, 250 mg/l K⁺, and 600 mg/l Na⁺, and pH 4 to simulate a geothermal brine found in Sibayak, Indonesia. An electrochemical measurement was performed by monitoring the open circuit potential over seven days, with the interruption by EIS every 22 hours. The experiments were performed at room temperature and 150 °C (1 MPa) in an oxygen-free environment. Impedance spectra showed a reduction of the total impedance value of approximately 10 times for specimens measured at 150 °C compared to the specimens measured at room temperature, suggesting a less stable layer at high temperature.

Abstract: This study focused on the fabrication of chitosan-polyethylene oxide sensitive thin film. The polyethylene oxide was used as an additive to enhance the electrical properties of chitosan towards ethanol and methanol gases. The chitosan-polyethylene oxide sensitive film was fabricated using electrochemical deposition technique to deposit a thin film of the sensitive blend on the printed circuit board surface. The sensitive blend electrical (I-V) properties were tested using a specific developed test chamber. Ethanol and methanol volatile organic compound gases were chosen in this work to study the thin sensing properties of the chitosan-polyethylene oxide film. The analyzed data demonstrated that chitosan-polyethylene oxide sensitive film was capable to detect the VOC gas molecules and showed that the sensitive blend was significantly selective to ethanol over methanol gas with output values of 0.31 µA and 0.023 µA respectively. Atomic force microscopy test was used to characterize the morphology and roughness of the pure chitosan and chitosan-polyethylene oxide sensitive films.

Abstract: Electrochemical deposition of Al-doped ZnO (AZO) on the ITO glass was investigated in baths containing various concentrations of aluminum nitrate. The electrochemical and chemical reactions can be deduced by means of investigating cathodic polarization curves and time/electroplating-current curves for further characterizing structures of ZnO and AZO, and establishing growth mechanism. High-quality AZO nanorods, depositing on ITO substrate that coated with ZnO seed-layer, were utilized the electrochemical method at-1.0 V (against a reference electrode of Ag/AgCl in 3.0M KCl) in the bath of 90 °C. After annealing at 350 °C, ZnO and AZO nanorods were analyzed by field-emission scanning electron microscope (FESEM) to explore the morphology of nanostructure. The SEM image displayed that the lower Al³⁺ concentrations (20 ~ 60 μM) in the bath, the average diameter of nanorods decreased; while the Al³⁺ concentrations excessed over 60 μM, the morphology of the AZO nanorods turned into partial-area nanosheets instead of the nanorods spread. The crystal structure of the AZO nanorods were identified by using grazing-incident X-ray diffraction (GIXRD). The patterns of the Al³⁺ ions in the range of 20 ~ 60 μM in the bath showed that the preferred orientations were along with the [002] direction which confirmed the result of AZO nanorods well aligned in c-axis orientation, and the characterized peak (002) slightly shifted to the right suggested that Al atoms had doped into the ZnO lattice. We also adopted the X-ray photoelectron spectroscopy to characterize the elemental and chemical compositions of the AZO nanorods. XPS spectrums confirmed that the Al atoms successfully doped. Finally, for identifying the optimal boundary condition of Al content in ZnO, the nanorods with various Al concentrations were utilized via dye-sensitized solar cells (DSSC) experiment with the standard solar Simulators (AM1.5G) and J-V Measurement. We found that the AZO nanorods as the photoanode contained 2.84 at.% Al (60 μM aluminum nitrate in the bath) which performed the highest fill-factor (0.53) and the maximum efficiency (0.41%).

Abstract: Novel hybrid Co/UHMWPE biocoatings were obtained by electrochemical deposition of cobalt from a cobalt sulfate plating bath with ultra high molecular weight polyethylene (UHMWPE - particle size of 10 μm) as dispersed particles in order to provide possible biomedical coatings applications. The surface morphology and topography, roughness and chemical composition were investigated, as a function of UHMWPE particles concentration in the plating bath by scanning electron microscopy (SEM), atomic force microscopy (AFM) and energy dispersive X-ray analysis (EDX). Electrochemical corrosion resistance investigations were carried out in simulating body fluid solution (SBF), using electrochemical impedance spectroscopy (EIS) method at different exposure times. The results proved a good corrosion resistance of the obtained hybrid Co/UHMWPE coatings.

Abstract: The n-type Cu₂O films were deposited on ITO substrate by three-electrode electrochemical deposition method in a CuSO₄-lactic acid electrolyte. The effects of electrolyte pH, bath temperature, and annealing treatment on films’ conductivity and their photoelectrochemical activity were investigated by X-ray diffraction (XRD), photocurrent (I-t) and mott-schottky (M-S) plots. The results show that the n-type Cu₂O could be electrodeposited at electrolyte pH of 8.5, 9 and 10, and the electrolyte temperature did not change the films’ conductivity. The highest n-type photocurrent density of 0.014 mA /cm² and carrier concentration of 2.3×10¹⁹ cm^-3 was obtained when the electrolyte pH was 8.5 and the bath temperature was 60°C. With increasing annealing temperature from 150°C to 400°C, the photocurrent density and carrier concentration of n-type Cu₂O thin films correspondingly increased, indicating that heat treatment is helpful to improve the photoelectrochemical activity.