Anodic Deposition Research Articles

Effects of deposition time and current density on PbO2 electrosynthesis from methanesulfonate electrolyte

This work investigated the effects of current density and deposition time on the properties of electrodeposited PbO2. The PbO2 preparation was conducted on Ti/SnO2–Sb substrates by galvanostatic anodic deposition in a newly proposed methanesulfonate electrolytic solution. Phase constituents and microstructures of the deposited PbO2 coatings were characterized. Increasing current density in the range ≤ 100 mA cm− 2 leads to the formation of highly textured coatings with an increased content of α-PbO2 phase. Concurrently, a high current density favors a compact and flat surface morphology. The study of deposition time indicates a change of crystallite growth manner from an initially random growth to a later-stage preferred growth along distinct orientations. The change of crystallite growth is corroborated by the cross-sectional microstructures of the PbO2 deposits. The microstructural transition occurs only in the initial deposition stage. After a brief period, prolonged electrodeposition barely changes the surface morphology of PbO2 coatings.

Electrodeposition and Photocharacterization of In2Se3 Thin Films Using PP-ALD for Use As a Potential Photoanode

Indium (III) selenide is an n-type semiconductor that displays 4 main crystal structures. While the more prevalent α and β structures have a direct bandgap of 1.62 eV, the γ structure has been found to have a bandgap of 1.9 eV.1,2 In current work, In2Se3 films were deposited using a pulse potential atomic layer deposition (PP-ALD) technique derived from E-ALD that relies upon the principles of ALD and underpotential deposition (UPD) to create ordered atomic layers. In PP-ALD both precursors, In and Se, are present in one solution that is pumped through the flow cell introducing the ions to the substrate. A cathodic pulse is then used to reductively deposit limited amounts of In and Se on the substrate surface, followed by an anodic pulse used to oxidatively strip any bulk In away from the surface leaving atomic layers of In2Se3. At pH=1, the deposition process creates bubbles in the flow cell that lead to regions of limited deposition. However, at pH=2, less bubbles are formed during the deposition process, leading to more uniform samples. Further investigations into the optimal cathodic and anodic deposition potentials for the PP-ALD program at pH=2 need to be done. These In2Se3 films have been demonstrated to have good photocurrent and have potential as an n-type photoanode in photoelectrochemical cell applications. Czerniawski, J.; Stickney, J.; Electrodeposition of In2Se3 Using Potential Pulse Atomic Layer Deposition. J. Phys. Chem. C 2016. 120, 16162-16167.Chang, K.; Lahn, S.; Chang, J. Growth of single-phase In2Se3 by using metal organic vapor deposition with dual-source precursors. Appl. Phys. Lett. 2006. 89, 182118.

Electrodeposition of Adherent MnO2 Films with Optimized Current Collector Interface for 3D Li-Ion Electrodes

Three-dimensional (3D) architectures for high-performance energy storage devices has been the subject of ongoing investigations targeting their integration in autonomous microelectronic systems. In this paper we present a route toward the realization of high capacity LiMn2O4 (LMO) cathode films for 3D thin-film lithium-ion batteries. One of the critical steps in the process is the electrodeposition of MnO2 coatings also known as electrolytic manganese dioxide (EMD) films. The main challenges of depositing thick enough EMD films directly on the current collector often lay in achieving a good film adhesion and preventing oxidation of non-noble current collectors such as TiN and Ni. Indeed, whereas EMD is typically used as powder for primary MnO2 based batteries and thus delamination from the current collector is desired, well adherent films are required for 3D thin-film batteries. To improve the adhesion of the EMD films we modify the surface of the current collector by means of nanometer thin seed layer coatings, which also prevent the oxidation of the underlying current collector substrate during the anodic deposition process. As a result, submicron to micron thick EMD films with good adhesion were deposited on various current collectors. The acidity of the electrolyte solutions was adjusted depending on the type of the surface coating or current collector used. The mechanism of the EMD film growth and morphology on different substrates will be discussed. Compatibility of the proposed current collector interface modification for the electrodeposition of conformal thick EMD films on high-aspect ratio microstructures was demonstrated. Finally, conversion of the EMD to LMO films is shown at low enough temperatures to be compatible with the underlying substrates. The functionality and high rate performance of the 3D LMO electrodes in Li-ion cell is demonstrated. Figure: Electrolytic manganese dioxide (EMD) films coated conformally on high aspect ratio pillar arrays for 3D thin-film batteries. Figure 1

Porous oxide electrocatalysts for oxygen evolution reaction prepared through a combination of hydrogen bubble templated deposition, oxidation and galvanic displacement steps

Porous oxide layers active in the oxygen evolution reaction (OER) were prepared with the following sequence of steps: (i) porous Pb was produced by cathodic hydrogen bubble templated electrodeposition; (ii) Pb was partially converted to its oxides; (iii) Co3O4 shells were formed on the surface of lead/lead oxides nanowires by spontaneous galvanic displacement reactions. The effect of deposition current density and charge on the porous Pb morphology was studied. Deposits with extended surface areas were obtained and then oxidized in neutral Na2SO4 solutions. Pb and PbO2, initially coexisting in oxidized samples, underwent a spontaneous reaction leading to the formation of Pb3O4. Both PbO2 and Pb3O4 spontaneously reacted with Co2+ to yield Co3O4 layers. Co-modified electrodes described in this work had higher activity in oxygen evolution reaction (OER) than those obtained by submitting to galvanic displacement porous PbO2 layers prepared by oxygen bubble templated anodic deposition.

Anodic Electrophoretic Deposition of Graphene Oxide on 316L Stainless Steel with pH-Dependent Microstructures

This paper describes anodic electrophoretic deposition of graphene oxide (GO) on 316L SS with pH-dependent microstructures. GO flakes were synthesized by modified Hummers’ method. Detailed studies on structural characteristics, thermal stability, and elemental composition of the GO flakes were carried out using advanced characterization techniques. Results showed successful oxidation and exfoliation forming GO flakes that are hydrophilic in nature. Acidic (pH 3.4) and basic (pH 11) aqueous GO suspensions were prepared, and the zeta potential as well as the average particle size distribution of the suspensions was ascertained. The GO suspensions were exhibiting zeta potential values of −32.9 and −36.8 mV and average particle size of 1–2 µm and 800–900 nm at acidic pH of 3.4 and alkaline pH of 11, respectively. Using anodic electrophoretic deposition (EPD) methods, GO was coated on 316L SS substrate from acidic and alkaline suspension and coatings were characterized. The increased value of ID/IG by Raman spectra analysis, partial restoration of C = C skeleton in the de-convoluted C 1s XPS spectra analysis, and the presence of C–C and C–H stretching bands in ATR-FTIR spectra were correlated with partial reduction of GO during the deposition on 316L SS surface. Though there was no difference in the chemical composition of the coatings formed from the acidic and alkaline pH suspension, atomic force microscopy and field emission scanning electron microscopy characterization showed difference in topography and morphology of the coatings. 316L SS substrates coated with GO in acidic pH showed higher RMS and average roughness and dense agglomerated wrinkled microstructure compared to substrates coated with alkaline pH suspension. Again GO coating from acidic pH suspension showed hydrophobicity. The present study showed that the microstructures of the GO coatings on 316L SS can be tuned by varying the pH of the GO suspension during EPD process.

Impact of metal matrix composite on the evolution and erosion performance characteristics of non lubricated-dry abrasive degradation of ternary composite coating for refineries system

Abstract The application of rational design principles and process in electrodeposition can eliminate many engineering catastrophes related to corrosion and micromechanical failure in service. This has led to appreciate the need of surface modification on component for enhance life span. Admixed Zn-30Al-13Ti-chloride composite bath was electrolytically prepared and successfully deposited on UNS G10150 mild steel substrate by zinc dual anode deposition processes within an interval of applied current density, particle concentration and constant time. The codeposition of Zn-Al-Ti coating was studied in the presence of other bath ingredient. The effect of deposition current and particle concentration on structural property, adhesion behaviour, ideal crystal orientation, surface topography and electrochemical properties of Zn-Al-Ti alloy coating series on mild steel were analytically examined. The wear stability of the developed composite materials was examined via sliding reciprocating rig. The structural integrity was examined with scanning electron microscope equipped with EDS, X-ray diffraction; Atomic force microscope, dura scan micro-hardness tester and 3 μ metrohm Potentiostat/galvanostat. Interestingly the induced activity of the Zn-Al-Ti chloride composite alloy results into excellent structural modification and stable crystal precipitation within the structural interface as a result of Zn3Al, Zn2Ti and ZnAl3Ti2 intermetallic phase. The obtained results showed that the introduction of Ti particles in the presence of other bath additive in the plating bath mostly modified the surface and brings an increase in the microhardness, corrosion resistance and reduce wear deformation of Zn-Al-Ti chloride composite alloy.

Effect of Electrodeposition Potential on Surface Free Energy and Supercapacitance of MnO2 Thin Films

The effect of anodic deposition potential on the supercapacitance of manganese dioxide (MnO2) and effect of surface free energy (SFE) on the supercapacitance are discussed. MnO2 thin films have been synthesized using a potentiostatic electrodeposition method. Their structure, morphology, wettability, electrochemical properties and supercapacitance are discussed. The observed specific capacitance (Cs) of MnO2 thin films is 127 F/g for the deposition potential at 1.20 V/Ag/AgCl. These films also show better stability for over 1000 cycles. The porous MnO2 thin films lead to high SFE and a corresponding high value of specific capacitance.

Voltammetric Determination of Bisphenol A Based on Its Anodic Deposition at Chitosan-Graphene Modified Glassy Carbon Electrode under UV Irradiation

Voltammetric Determination of Bisphenol A Based on Its Anodic Deposition at Chitosan-Graphene Modified Glassy Carbon Electrode under UV Irradiation

Formation of Zein/Bioactive Glass Layers Using Electrophoretic Deposition Technique

Coatings of zein and zein/bioactive glass composites were produced on 316L stainless steel using anodic electrophoretic deposition (EPD). Zein and 45S5 bioactive glass were dispersed in a binary water/ethanol solution. The effects of the zein and bioactive glass concentrations as well as different water/ethanol ratios on the coating characteristics were investigated. Also, the influence of applied voltage and deposition time were analyzed. Prior to EPD, the zeta potential of zein, bioactive glass and zein/bioactive glass suspensions were measured as a function of the pH. The coatings were investigated by optical microscopy, scanning electron microscopy and atomic force microscopy. Coatings with pure zein are homogeneous when using an electrical field strength below or equal to 0.05 V/m. Higher voltages led to a discoloration of the solution which could result from a conformational change of zein. The co-deposition of zein/bioactive glass is very sensitive to the applied voltage and the concentration of zein. High concentrations of zein (10 g/L) increase the viscosity of the solution and reduce the electrophoretic mobility of the bioactive glass. Equal concentration of zein and bioactive glass at a pH of 7.5 with a low electric field strength were found to be the optimum conditions.

A Permselective CeOx Coating To Improve the Stability of Oxygen Evolution Electrocatalysts.

Highly active NiFeOx electrocatalysts for the oxygen evolution reaction (OER) suffer gradual deactivation with time owing to the loss of Fe species from the active sites into solution during catalysis. The anodic deposition of a CeOx layer prevents the loss of such Fe species from the OER catalysts, achieving a highly stable performance. The CeOx layer does not affect the OER activity of the catalyst underneath but exhibits unique permselectivity, allowing the permeation of OH- and O2 through while preventing the diffusion of redox ions through the layer to function as a selective O2 -evolving electrode. The use of such a permselective protective layer provides a new strategy for improving the durability of electrocatalysts.

A Permselective CeOx Coating To Improve the Stability of Oxygen Evolution Electrocatalysts

AbstractHighly active NiFeOx electrocatalysts for the oxygen evolution reaction (OER) suffer gradual deactivation with time owing to the loss of Fe species from the active sites into solution during catalysis. The anodic deposition of a CeOx layer prevents the loss of such Fe species from the OER catalysts, achieving a highly stable performance. The CeOx layer does not affect the OER activity of the catalyst underneath but exhibits unique permselectivity, allowing the permeation of OH− and O2 through while preventing the diffusion of redox ions through the layer to function as a selective O2‐evolving electrode. The use of such a permselective protective layer provides a new strategy for improving the durability of electrocatalysts.

In situ atomic force microscopy study of nano-micro sodium deposition in ester-based electrolytes.

We report an in situ analysis of nano-micro sodium deposition in an ester-based electrolyte using atomic force microscopy. It is found that sodium dendrites are effectively suppressed by adding fluoroethylene carbonate (FEC) as an electrolyte additive. The decomposition of FEC provides a NaF-containing solid electrolyte interphase with homogenous morphology and high modulus, leading to stable sodium deposition and high Coulombic efficiency (88% over 50 cycles) of the sodium metal anode.

Development of a Wire Reference Electrode for Lithium All-Solid-State Batteries with Polymer Electrolyte: FEM Simulation and Experiment

Electrochemical impedance spectroscopy (EIS) is a powerful technique to study interface kinetics in lithium ion batteries. In order to separate the contributions of the working and counter electrode, a reference electrode (RE) is crucial. However, size and shape of the RE strongly influence the quality of the measurement data. In this study we define two criteria that enable the theoretical quality assessment of a wire-shaped RE as a function of its diameter. With help of a simplified Newman-type battery model we show that small wire diameters are essential in order to obtain meaningful EIS data, in particular when using polymer electrolytes, which have comparably low ionic conductivity. Therefore, a gold plated tungsten wire with 10 μm diameter is chosen as preferred RE. It is placed between two layers of electrolyte and lithiated before use to ensure a long-term stable reference potential. Using this setup, artifact-free EIS spectra are obtained for lithium/lithium and lithium/LFP cells with polymer electrolyte. Finally, two applications are shown for which a RE is indispensable: (I) the symmetry of anodic and cathodic lithium dissolution and deposition kinetics is characterized; (II) the growth of the anode and cathode impedance of a lithium/LFP cell during cycling is monitored.

Fabrication, characterization and photoelectrochemical activity of tungsten-copper co-sensitized TiO2 nanotube composite photoanodes

Tungsten-copper co-sensitized TiO2 nanotube films on titanium substrate, used as photoanodes in photoelectrochemical (PEC) water splitting to produce hydrogen, have been synthesized via anodization and chemical bath deposition (CBD) methods. Field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD) were used to study the morphology and elemental composition of the synthetic samples. UV–Vis diffuse reflection spectroscopy (UV–Vis DRS) was sued to investigate the optical features of the samples. The impact of copper and tungsten ratio on the photocatalytic behavior of co-sensitized TiO2 nanotube photoelectrodes in PEC water splitting has been investigated. High photocatalytic activity has been exhibited by the co-sensitized TiO2 nanotube samples due to the synergistic effects of the copper and tungsten. Sample T4 had the highest photoelectrochemical activity compared with other samples. In addition, this sample exhibited outstanding photochemical stability even after four runs in the photocatalytic test. A simple method for the synthesis of high performance co-sensitized TiO2 nanotube photocatalysts for application in solar energy conversion has thus been proposed in this work. The advantages of these new photoanodes for practical applications are low cost, ease of synthesis, high activity in visible light and excellent stability.

Anodic deposition of nanostructured hematite film using agarose gel as template. Application in water splitting

The present study shows the results obtained in anodic electrodeposition of hematite precursor films in agarose gel template and photoelectrochemical characterization of the prepared hematite films. The peak current in cyclic voltammetry increases after each scan of the potential between −0.1 and 1.3 V for FTO electrode covered with a film of agarose gel in 0.1 M iron sulfate solution. The hematite samples with different thicknesses were prepared using template electrodeposition and annealing in air. The obtained nanostructured films were characterized by field emission scanning electron microscopy, X-ray diffraction, UV–vis spectroscopy, X-ray photoelectron spectroscopy and electrochemical impedance spectroscopy. The results show that a synergistic improvement of photocurrent density (1.14 mAcm−2 at 1.23 V vs RHE) is induced by Sn-doping and slight surface modification of hematite with thin and discontinuous NiO film. The results indicate that thicker hematite films and hematite films strongly modified with NiO nanostructures show a reduced photoactivity.

On direct internal methane steam reforming kinetics in operating solid oxide fuel cells with nickel-ceria anodes

Major operating challenges remain to safely operate methane fuelled solid oxide fuel cells due to undesirable temperature gradients across the porous anode and carbon deposition. This article presents an experimental study on methane steam reforming (MSR) global kinetics for single operating SOFCs with Ni-GDC (gadolinium doped ceria) anodes for low steam to carbon (S/C) ratios and moderate current densities. The study points out the hitherto insufficient research on MSR global and intrinsic kinetics for operating SOFCs with complete Ni-ceria anodes. Further, it emphasizes the need to develop readily applicable global kinetic models as a subsequent step from previously reported state-of-art and complex intrinsic models. Two rate expressions of the Power law (PL) and Langmuir-Hinshelwood (LH) type have been compared and based on the analysis, limitations of using previously proposed rate expressions for Ni catalytic beds to study MSR kinetics for complete cermet anodes have been identified. Firstly, it has been shown that methane reforming on metallic (Ni) current collectors may not be always negligible, contrary to literature reports. Both PL and LH kinetic models predict significantly different local MSR reaction rate and species partial pressure distributions along the normalized reactor length, indicating a strong need for further experimental verifications.

Biocompatibility of Titania Nanotube Coatings Enriched with Silver Nanograins by Chemical Vapor Deposition.

Bioactivity investigations of titania nanotube (TNT) coatings enriched with silver nanograins (TNT/Ag) have been carried out. TNT/Ag nanocomposite materials were produced by combining the electrochemical anodization and chemical vapor deposition methods. Fabricated coatings were characterized by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy. The release effect of silver ions from TNT/Ag composites immersed in bodily fluids, has been studied using inductively coupled plasma mass spectrometry (ICP-MS). The metabolic activity assay (MTT) was applied to determine the L929 murine fibroblasts adhesion and proliferation on the surface of TNT/Ag coatings. Moreover, the results of immunoassays (using peripheral blood mononuclear cells—PBMCs isolated from rats) allowed the estimation of the immunological activity of TNT/Ag surface materials. Antibacterial activity of TNT/Ag coatings with different morphological and structural features was estimated against two Staphylococcus aureus strains (ATCC 29213 and H9). The TNT/Ag nanocomposite layers produced revealed a good biocompatibility promoting the fibroblast adhesion and proliferation. A desirable anti-biofilm activity against the S. aureus reference strain was mainly noticed for these TiO2 nanotube coatings, which contain dispersed Ag nanograins deposited on their surface.

Silver doped hydroxyapatite coatings by sacrificial anode deposition under magnetic field.

Uniform distribution of silver (Ag) in the hydroxyapatite (HA) coated Ti surface has been a concern for which an attempt has been made to dope Ag in HA coating with and without magnetic field. Cathodic deposition technique was employed to coat Ag incorporated hydroxyapatite coating using a sacrificial silver anode method by using NdFeB bar magnets producing 12 Tesla magnetic field. While uniform deposition of Ag was observed in the coatings under magnetic field, dense coating was evident in the coating without magnetic field conditions. Uniformly distributed Ag incorporated HA in the present study has potential to fight microorganism while providing osseoconduction properties of the composite coating.

Pd-MnO2 nanoparticles/TiO2 nanotube arrays (NTAs) photo-electrodes photo-catalytic properties and their ability of degrading Rhodamine B under visible light

Pd-MnO2/TiO2 nanotube arrays (NTAs) photo-electrodes were successfully fabricated via anodization and electro deposition subsequently; the obtained Pd-MnO2/TiO2 NTAs photo electrodes were analyzed by scanning electron microscopy (SEM), X-ray diffraction (XRD) and characterized accordingly. Moreover, the light harvesting and absorption properties were investigated via ultraviolet–visible diffuse reflectance spectrum (DRS); photo degradation efficiency was investigated via analyzing the photo catalytic degradation of Rhodamine B under visible illumination (xenon light). The performed analyses illustrated that Pd-MnO2 codoped particles were successfully deposited onto the surface of the TiO2 nanotube arrays; DRS results showed significant improvement in visible light absorption which was between 400 and 700nm. Finally, the photo catalytic degradation efficiency results of the designated organic pollutant (Rhodamine B) illustrated a superior photocatalytic (PC) efficiency of approximately 95% compared to the bare TiO2 NTAs, which only exhibited a photo catalytic degradation efficiency of approximately 61%, thus it indicated the significant enhancement of the light absorption properties of fabricated photo electrodes and their yield of OH radicals.

Preparation of porous oxide layers by oxygen bubble templated anodic deposition followed by galvanic displacement

Galvanic displacement reactions between porous PbO2, prepared by oxygen bubble templated anodic deposition, and the low-valent cations Mn2+, Co2+ and Sn2+, have been studied using electrochemical methods, SEM-EDS and XPS. These reactions occur at open circuit by immersion of PbO2 coated electrodes in aqueous solutions of the cations and lead to the formation of outer oxide layers onto porous PbO2, whose composition and chemical nature have been assessed by XPS. The growth of the outer oxide layers has been studied by combining Evans’ diagrams with SEM-EDS and XPS results, as a function of experimental variables, such as the chemical nature of the cations, their concentration and the solution temperature. The combination of oxygen bubble templated anodic deposition and galvanic displacement provides a route for the preparation of porous low-conductivity electroactive oxides not attainable by direct electrodeposition. Deposition of Co3O4 thin layers by galvanic displacement results in a strong enhancement of the activity of porous PbO2 electrodes in the oxygen evolution reaction.