Combination Of Electrochemical Deposition Research Articles

CuO/Co3O4 materials grown directly on nickel foam for high-performance supercapacitor electrode

Electrochemical deposition and successive ionic layer adsorption and reaction (SILAR) are two widely used techniques for preparing semiconductor materials. However, there is limited research on combining the two methods to prepare CuO and Co3O4 composites for supercapacitor applications. In this study, CuO/Co3O4 semiconductor composites with spherical (S–CuO/Co3O4) and wheat spike (W–CuO/Co3O4) morphologies were prepared on nickel foam substrate using a combination of electrochemical deposition and successive ion-layer adsorption. The composites were characterized using X-ray diffraction, X-ray photoelectron spectroscopy, and field emission scanning electron microscopy to confirm their composition and morphology. The electrochemical properties of CuO/Co3O4 materials were investigated using CV, GCD, and EIS. The results show that the load cycle has a significant impact on the performance of CuO/Co3O4, with a load period of 10 cycles exhibiting the best electrochemical performance. A comparison also reveals that the performance of the W–CuO/Co3O4 electrode is better than that of the S–CuO/Co3O4 electrode. In particular, at 1 mA/cm2 current density, the specific capacity of the W–CuO/Co3O4-10 electrode is 86.0 mAh/g, which is larger compared to S–CuO/Co3O4-10 electrode (55.8 mAh/g). After 5000 cycles of galvanostatic charge/discharge, the capacitance retention rate of the W–CuO/Co3O4-10 electrode remains 76.9 %. In addition, two water-system symmetrical supercapacitors connected in series can light up the LED for 8 min and still maintain a certain brightness. Modifying the morphology of composites has a significant impact on improving the capacitive properties of composites. This study demonstrates that the prepared CuO/Co3O4 composite material has good application potential as electrode material for supercapacitors.

Nonprecious High‐Entropy Chalcogenide Glasses‐Based Electrocatalysts for Efficient and Stable Acidic Oxygen Evolution Reaction in Proton Exchange Membrane Water Electrolysis

AbstractHere,nonprecious high‐entropy chalcogenide glasses (N‐HECGs) consisting of Co, Fe, Ni, Mo, W, and Te are demonstrated in a first demonstration of acidic oxygen evolution reaction (OER). N‐HECGs electrocatalysts with high activity and stability are synthesized using a hierarchical hybrid approach based on a combination of electrochemical deposition and tellurization process. The as‐prepared CoFeNiMoWTe N‐HECGs electrocatalysts exhibit an amorphous, porous structure of arrayed nanosheets with abundant active sites and the increased valence states of metal cations due to the incorporated non‐metallic Te, enabling the enhancement of glass forming ability and the valence states of metal elements. Thanks to the combination of their unique geometrical and chemical structure, as well as high configuration entropy nature and high corrosion‐resistance ability, the resultant CoFeNiMoWTe N‐HECGs exhibit excellent acidic OER catalytic performance with a superior overpotential of 373 mV and outstanding stability of 100 h at the current density of 10 mA cm−2 in 0.5 m H2SO4. Moreover, the CoFeNiMoWTe‐based proton exchange membrane water electrolyzer is demonstrated to require a cell voltage of 1.81 V at 70 °C to obtain the practically high current density of 1 A cm−2, and exhibits remarkably long‐term stability for 100 h with small potential degradation of only 30 mV.

Per-fluorinated chemical free robust superhydrophobic copper surface using a scalable technique

Robust superhydrophobicity is of immense practical interest in a wide range of applications including self-cleaning, anti-icing, anti-corrosion, atmospheric water harvesting, desalination, condensation, and oil-water separation. However, biohazard associated with the prevalent use of per-fluorinated synthetic chemicals in making these surfaces and the gradual loss of superhydrophobicity have been major roadblocks. Here we develop an environment-friendly and industrially scalable superhydrophobic copper surface using a combination of electrochemical deposition and Lauric acid functionalization. We optimized the synthesis process for ensuring the robustness of these superhydrophobic surfaces. The surface exhibits contact angles as high as 158° with excellent droplet rebounding, self-cleaning, anti-icing, and dropwise condensation abilities. Thermal stability in the range of −15°C to 150°C, mechanical robustness against abrasion, chemical stability under aqueous, acidic, and basic medium, and the excellent plastron layer stability under long-time underwater immersion attest to the high quality of superhydrophobic surfaces for large-scale applications. These coatings when implemented on the curved surface of a copper tube demonstrated appreciable improvement in condensation behavior. Our method provides a sustainable approach for suitable technological interventions in energy and potable water applications requiring robust environment-friendly superhydrophobic surfaces.

Enantioselective recognition of amino acid based on electrochemical deposition and X-ray diffraction technology

Addition of D-Asp in the electrochemical deposition process of Bismuth film resulted the generation of a new diffraction peak in X-ray diffraction (XRD) spectrum. This phenomenon was not observed in the situation of L-Asp. The new diffraction peak might suggest D-Asp could result in the generation of a specific Bismuth structure. Enantioselective recognition of D- and L-Asp can be realized based on this new XRD peak. The limit of detection was determined to be 3.5 × 10−8 and 1.7 × 10−8 mol L−1 for D- and L-Asp, respectively. The XRD spectra of electrodeposited Copper films fabricated in the presence of D- or L-Asp showed different lattice plane diffraction peak intensity ratios. The reason was believed to be chirality induced different binding capabilities of Asp enantiomers that influenced Copper film growth. Therefore, the combination of electrochemical deposition using Copper as metal source and XRD technology can be used to achieve enantioselective recognition of Asp. The limit of detection for D- and L-Asp were determined to be 1.5 × 10−10 and 1.2 × 10−11 mol L−1, respectively.

Graphene oxide-promoted Ti/PbO2 photoanode with photoelectric synergy effect for efficient photoelectrocatalytic degradation of reactive brilliant blue

The development of semiconductor-based photoelectrocatalysts with superior activity is of great importance for water purification. Here, we fabricated graphene oxide (GO)-wrapped Ti/PbO2 photoanodes by combination of electrochemical deposition and electrophoretic deposition process. The as-obtained composite electrodes showed better performance for photoelectrocatalytic (PEC) degradation of reactive brilliant blue KN-R, as compared with that of Ti/PbO2 reference. Experimental results demonstrated that the efficient PEC performance of graphene oxide (GO)-wrapped Ti/PbO2 photoanodes could be ascribed to the low charge transfer resistance, large electrochemical active areas, and high separation efficiency of induced electrons/holes. Furthermore, a significant photoelectric synergy effect can be observed for the graphene oxide (GO)-wrapped Ti/PbO2 photoanodes during the photoelectrocatalytic process.

Three-Dimensional Graphene/MnO2 Nanowalls Hybrid for High-Efficiency Electrochemical Supercapacitors

In this paper, a facile method is designed to fabricate three-dimensional (3D) graphene (GR)/manganese dioxide (MnO2) nanowall electrode material. The 3D GR/MnO2 hybrid is prepared by a combination of electrochemical deposition (ELD) and electrophoresis deposition (EPD), followed by thermal reduction (TR). Firstly, the 3D graphene oxide (GO)/MnO2 hybrid is obtained by the ELD–EPD method. Secondly, the 3D GR/MnO2 hybrid is obtained through hydrogen reduction at a certain temperature. The as-fabricated hybrid has been characterized by scanning electron microscope (SEM), transmission electron microscope (TEM) and Raman spectroscopy. The electrochemical properties have been also measured by cyclic voltammetry. The results showed that the 3D GR/MnO2 nanowalls hybrid has a high specific capacitance of 266.75[Formula: see text]Fg[Formula: see text] and a high energy density of 25.36[Formula: see text]Whkg[Formula: see text]. Moreover, a high specific capacitance (240.15[Formula: see text]Fg[Formula: see text]) at a high scan rate of 200[Formula: see text]mVs[Formula: see text] (90% capacity retention) has been also obtained. Additionally, the hybrid can serve directly as the electrodes of supercapacitor without adding binder. This work provides a novel road to fabricate a binder-free 3D GR-based hybrid for high-performance energy storage devices.

A Self-Supported Porous Hierarchical Core–Shell Nanostructure of Cobalt Oxide for Efficient Oxygen Evolution Reaction

Increasing the active surface area of an electrocatalyst is crucial for effective oxygen evolution reaction (OER). Here, a sophisticated electrode that uses the advantages of porous/hollow nanostructure, hierarchical nanostructure, and self-supported structure simultaneously is demonstrated for the first time. A self-supported porous hierarchical core–shell structure (PHCS) of cobalt oxide is synthesized by the combination of electrochemical deposition and electrochemical treatment. The treatment introduces numerous pores into the core of a core–shell structure, and it decreases the particle size of cobalt oxide to <5 nm, markedly increasing the surface area of the resultant structures. The electrochemical surface area of PHCS is 1.6 greater than that of hierarchical core–shell cobalt oxide, and is ∼20 times greater than that of cobalt oxide nanowires. The PHCS is extremely active in the OER, with the overpotential required for a current density of 100 mA cm–2 being as small as 300 mV. The Tafel slope is ...

Designing non-noble/semiconductor Bi/BiVO4 photoelectrode for the enhanced photoelectrochemical performance

Bi/BiVO4 photoelectrode was prepared on FTO glass by the combination of electrochemical deposition, heating treatment and photo-assisted reduction method at room temperature. All of the samples were characterized by X-ray diffraction spectrum (XRD), scanning electron microscope (SEM) and UV–vis diffuse reflectance spectrum (DRS), respectively. The results indicated that metallic Bi particles were well deposited on porous BiVO4 film during the deposition process of photo-assisted reduction, resulting in a greatly broadened visible light absorption edge than that of BiVO4 alone. The optimized photoelectrochemical (PEC) performance of Bi/BiVO4-60 was further verified by linear scan voltammetry (LSV), current-time (I-t) and incident photon-to-current efficiency (IPCE), respectively. It was conjectured the broadened visible light response range of Bi/BiVO4 PEC system and the increased counteraction against positive charge both were caused by the electron transferred from BiVO4 to Bi, and thus effectively facilitated the separation and transfer of photo-generated carriers and thus promote the PEC water splitting performance.

The Mechanical Properties and Corrosion Behavior of Double-Layered Nano Hydroxyapatite-Polymer Coating on Mg-Ca Alloy

Nano-hydroxyapatite (HA)/poly(e-caprolactone) (PCL) coatings with thickness of about 45-55 μm were prepared on the surface of a Mg-Ca alloy by a combination of electrochemical deposition and dip-coating methods. The results indicate that incorporation of nano-HA as an inner layer affects the porosity of the PCL-coated layer as top layer and enhances the corrosion resistance of Mg-Ca alloys. The nano-HA/PCL-coated samples showed higher R p (823.1 kΩ cm2) and lower i corr (5.85E−2 µA/cm2) compared with uncoated. Significant enhancement in the compressive strength was observed in the both nano-HA/PCL and PCL compared with uncoated samples after 10 days immersion in SBF.

Controlled Construction of Hierarchical Nanocomposites Consisting of MnO2 and PEDOT for High‐Performance Supercapacitor Applications

AbstractThe integration of hierarchical nanostructure design and encapsulation strategies using a combination of electrochemical deposition, hydrothermal, and in situ reaction methods has been recognized as one of the most effective strategies to realize practical applications of various supercapacitor materials. Herein, a facile and scalable method is developed to synthesize a core–shell–branch hierarchical MnO2@PEDOT@MnO2 composite by using a simple electrochemical deposition strategy. The proposed synthesis method facilitates the structural integration of three‐dimensional nickel foam and the synergy of different electroactive materials, which offers several advantages including simplicity, efficiency, no binder, and low cost. The as‐prepared, freestanding, hierarchical MnO2@PEDOT@MnO2 electrodes exhibit high specific capacitance and rate capability. An asymmetric supercapacitor is fabricated with the hierarchical MnO2@PEDOT@MnO2 nanocomposite as the positive electrode, activated carbon as the negative electrode, and Na2SO4 aqueous solution as the electrolyte. The asymmetric supercapacitor can be cycled reversibly in a high‐voltage window of 0–1.8 V and exhibits a high energy density of 47.8 Wh kg−1 at a power density of 180 W kg−1, indicating remarkable rate capability as well as reasonable cycling performance with 91.3 % retention after 5000 cycles.

Controlled Growth of One-Dimensional Metal–Semiconductor and Metal–Carbon Nanotube Heterojunctions

Aligned and diameter-controlled one-dimensional nickel–carbon nanotubes and Ag–Si heterojunctions (see Figure) have been synthesized by a novel combination of electrochemical deposition and chemical vapor deposition with anodic aluminum oxide templates. No external catalysts are introduced in the chemical reactions. In the joint regions of the heterojunctions, no amorphous layers are found. These heterojunctions are significant for the development of electronics.

Electrochemical Processing of Layered Composite Coatings of Nickel - Aluminum - Alumina / Alumina - Yttria Stabilized Zirconia

ABSTRACTMultilayered coatings of single and dual particle metal matrix composites, with or without ceramic overlayers, have been produced by a novel combination of electrochemical deposition (electroplating and electrophoretic deposition) and reaction bonding. The coatings contain the following layers in a variety of combinations deposited on Ni substrates: (i) electroplated composites of Ni with Al and/or alumina particles, (ii) precursor Al + A12O3 + yttria stabilized ZrO2 transformed into A12O3 + yttria stabilized ZrO2 by the reaction bonding method, and (iii) yttria stabilized ZrO2. In order to determine the appropriate processing parameters for the multilayered coatings, uniform one-layer coatings were deposited and characterized. We find that in the dual particle Ni-Al-Al2O3 coatings the volume percent of the particles does not show a dependence on deposition current density. However, volume percent alumina in these coatings has a strong dependence on the amount of this particle in the plating bath, while the volume percent Al shows only a weak dependence on its bath content. Comparison of the deposition behavior of these dual particle with single particle coatings, containing Al or alumina only, reveals that the presence of Al in the bath interferes with the codeposition of alumina. This interference, however, is not reciprocal. When coatings containing Al are annealed, Ni and Al react to form a solid solution of Al in Ni (γ) or a two phase mixture of this solid solution and the intermetallic, Ni3Al, (γ-γ') depending on the annealing temperature. Finally, we find that the formation of the reaction bonded alumina plus yttria stabilized zirconia layer requires the oxidation resistance afforded by aluminum in the underlying electroplated layer.