Two-step Electrodeposition Technique Research Articles

Confinement and interface engineering boosting the capacitive performance by constructing NiCo-LDH@CoSe core-shell structure for supercapacitor

The strategic design of heterostructures in multicomponent composites is a promising approach for enhancing the properties of energy storage materials. While NiCo layered double hydroxide (NiCo-LDH) exhibits favorable ion exchange and redox capabilities, its nanostructure suffers from poor conductivity, leading to aggregation during charge and discharge cycles and compromising its electrochemical stability. This study presents the novel synthesis of NiCo-LDH@CoSe core-shell heterostructure using a two-step electrodeposition technique. The NiCo-LDH@CoSe heterojunction has remarkable electrochemical characteristics, boasting a high specific capacitance of 1965.4 F·g−1 at 1 A·g−1. It also exhibits an impressive rate performance of 74.4 % at 20 A·g−1, and retains 83.3 % of its capacitance after enduring 10,000 cycles at 30 A·g−1. The confinement and interface engineering of the heterojunction facilitate enhanced charge transfer from CoSe to NiCo-LDH, leading to exceptional performance and effectively addressing challenges such as poor conductivity, structural degradation, and nanoparticle clustering. The assembled NiCo-LDH@CoSe//AC hybrid supercapacitor also shows excellent performance. This research underscores the effectiveness of core-shell structure confinement and interface engineering in enhancing electrochemical performance.

Facile Route to Achieve a Hierarchical CuO/Nickel-Cobalt-Sulfide Electrode for Energy Storage.

Herein, a novel self-supporting CuO/nickel-cobalt-sulfide (NCS) electrode was designed in a two-step electrodeposition technique followed by a calcination process. Three-dimensional copper foam (CF) was exploited as the current collector and spontaneous source for the in situ preparation of the CuO nanostructures, which ensured sufficient deposition space for the subsequent NCS layer, thus forming abundant electrochemical active sites. Such a hierarchical structure is conducive to providing a smooth path for promoting electronic transmission. Therefore, the optimized CuO/NCS electrode exhibits outstanding energy storage capability with extremely superior specific capacitance (Cs) of 7.08 F cm-2 at 4 mA cm-2 and coulombic efficiency of up to 94.83%, as well as excellent cycling stability with capacitance retention of 83.33% after 5000 cycles. The results presented in this work extend our horizons to fabricate novel hierarchical structured electrodes applied to energy storage devices.

Enhancement in pool boiling performance of GNP/Cu-Al2O3 nano-composite coated copper microporous surface

An experimental analysis of pool boiling is conducted on the GNP/Cu-Al2O3 (GNP-graphene nano particle) nanocomposite coated copper surfaces at atmospheric pressure using DI (distilled water) as boiling fluid. A two-step electro-deposition technique is used for fabrication of these micro/nano porous coated surfaces. A modified surface structure is formed due to this deposition and various surface morphology parameters such as surface structure, roughness, wettability are analysed. Results show the enhancement in BHTC (boiling heat transfer coefficient) and CHF (Critical heat flux) in nano composite coated surfaces compare to the bare copper surface. The maximum CHF of 2415 (kW/m2) and BHTC of 171.28 (kW/m2K) is found in the NCCS (nano-composite coated superhydrophilic) surfaces which are 122% and 239% more than the bare copper surfaces. The boiling performance is augmented mainly because of the improvement in roughness, wettability and also for the high thermal conductivity of the GNP/Cu- Al2O3 nano coating. Quantitative study of the bubble dynamics like active nucleation site density, bubble emission frequency, departure diameter of bubbleand their impact on heat transfer performance in the case of NCCS surfaces is performed with high-speed visualization.

Enhancing electrochemical and photoelectrochemical degradation of organic dyes under visible irradiation with a novel Cu2O/BaHPO4-based photoelectrode

A highly active Cu2O/BaHPO4 photoanode was obtained using a simple two-step electrodeposition technique. The synthesised material was characterised by various methods, including X-ray diffraction (XRD), which revealed the orthorhombic phase of BaHPO4 and the cubic phase of Cu2O, while scanning electron microscopy coupled to energy dispersive X-ray spectroscopy (SEM-EDX) showed the platelet and prism morphology of BaHPO4 and Cu2O, respectively. The optical features of both compounds as well as their band gap energies were also evaluated and calculated using diffuse reflection spectroscopy (DRS). The vibrational properties of the photoanode were studied using Fourier transform infrared (FT-IR). The electrocatalytic activity (EC) of the samples were evaluated using a central composite design for surface response methodology (CCD-RSM) to determine the optimal conditions for Rhodamine B (RhB) degradation. The photoelectrocatalytic performance (PEC) of the Cu2O/BaHPO4 photoanode was about 98% in 5 min of reaction under visible irradiation, which was higher than BaHPO4 and Cu2O alone significating a quick separation of photoexcited carriers thanks to the excellent synergetic properties exhibited by the composite. This finding was corroborated by the results obtained from electrochemical impedance spectroscopy (EIS) and Mott-Schottky (MS) analysis. Various cationic and anionic dyes could be efficiently degraded. In addition, after 8 cycles, a non-significant decrease in the degradation rate was observed confirming the high cyclability of the photoanode. Therefore, Cu2O/BaHPO4 can be considered as a promising candidate for the efficient degradation of organic pollutants.

In-situ two-step electrodeposition of α-CD-rGO/Ni-MOF composite film for superior glucose sensing

Accurate and rapid determination of blood glucose levels is essential for real-time monitoring and management of diabetes mellitus, and nanomaterials-based nonenzymatic glucose sensing plays an increasingly significant role in this regard. Here, a simple two-step electrodeposition technique that was efficient, environmentally friendly, easily manipulated, and exceedingly controllable was adopted for the synthesis of metal-organic framework (MOF)/carbon material composites on a titanium mesh (TM), namely α-cyclodextrin functionalized reduced graphene oxide/nickel-based MOF (α-CD-rGO/Ni-MOF/TM), in which Ni-MOF served as the electrocatalyst for glucose oxidation, and rGO greatly enhanced the electrochemical performance of Ni-MOF, benefiting from α-CD effectively preventing aggregation of rGO nanosheets while also improving the stability of the composites, so that these endow the obtained nanomaterials exhibited remarkable electrocatalytic ability for glucose. Consequently, the as-prepared glucose sensor revealed two linear dynamic ranges of 0.65 μM− 4.828 mM with a sensitivity of 1395 μA mM−1 cm−2 and 4.828 − 9.178 mM with a sensitivity of 760 μA mM−1 cm−2 together with a rapid response time of only 1.9 s and a low detection limit of 0.3 μM as well as distinguished reproducibility, selectivity, and stability, further demonstrating the synergistic effects of this composite. The newly manufactured glucose sensing platform was also successfully used to detect glucose in real serum. Considering the convenience and controllability of two-step electrodeposition, the α-CD-rGO/Ni-MOF/TM composite holds great promise for commercial potential, and also provides direction and technical reference for the synthesis of MOF/carbon material composites.

Fabrication of Cu@G composite coatings and their pool boiling performance with R-134a and R-1234yf

ABSTRACT The present work explores the pool-boiling performance of refrigerants (R-134 and R-1234yf) on the plain Cu and graphene nanoplatelets (G) reinforced Cu matrix (Cu@G) composite coated heating surface. A two-step electrodeposition technique was employed to prepare microporous Cu@G composite coatings. Scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) studies confirmed the successful fabrication of microporous structure of Cu@G composite coatings. Surface profilometer investigation was done to know the surface roughness of prepared Cu@G composite coatings. Pool boiling experiments were carried out with increasing heat flux from 8.80 kW/m2 to 61.25 kW/m2 at a saturation temperature of 10°C. Test results of R-134 and R-1234yf were compared. The experimental results revealed that the heat transfer coefficients (HTCs) of R-134a were higher than R-1234yf for plain Cu and Cu@G composite coated heating surfaces.

Experimental Study of Pool Boiling Enhancement Using a Two-Step Electrodeposited Cu–GNPs Nanocomposite Porous Surface With R-134a

Abstract The fabrication of porous metallic composite coating on the heating surface to improve pool boiling heat transfer (BHT) performance has received significant attention in recent years. In this work, Cu–GNPs nanocomposite coatings, which were prepared on a copper substrate using various current densities through a two-step electrodeposition technique, were used as heating surfaces to study the pool BHT performance of refrigerant R-134a. The surface morphology, elemental composition, thickness, surface roughness, and porosity of prepared Cu–GNPs nanocomposite coatings are studied and presented in detail. All Cu–GNPs nanocomposite coated surfaces exhibited improved boiling performance compared to the plain Cu surface. The heat transfer coefficient (HTC) values for Cu–GNPs nanocomposite coated Cu surfaces prepared at 0.1, 0.2, 0.3, and 0.4 A/cm2 were improved up to 1.48, 1.67, 1.82, and 1.97, respectively, compared with the plain Cu surface. The enhancement in the HTC is mainly associated with the increase in surface roughness, active nucleation site density, and micro/nanoporosity of the heating surface.

Hierarchical CuCo2O4@CoS-Cu/Co-MOF core-shell nanoflower derived from copper/cobalt bimetallic metal–organic frameworks for supercapacitors

Rational design of composite materials with unique core-shell nanoflower structures is an important strategy for improving the electrochemical properties of supercapacitors such as capacitance and cycle stability. Herein, a two-step electrodeposition technique is used to orderly synthesize CuCo2O4 and CoS on Ni foam coated with Cu/Co bimetal metal organic framework (Cu/Co-MOF) to fabricate a hierarchical core-shell nanoflower material (CuCo2O4@CoS-Cu/Co-MOF). This unique structure can increase the electrochemically active site of the composite, promoting the Faradaic redox reaction and enhancing its electrochemical properties. CuCo2O4@CoS-Cu/Co-MOF shows a prominent specific capacitance of 3150 F g−1 at 1 A g−1, marvelous rate performance of 81.82% (2577.3 F g−1 at 30 A g−1) and long cycle life (maintaining 96.74% after 10,000 cycles). What is more, the assembled CuCo2O4@CoS-Cu/Co-MOF//CNTs device has an energy density of 73.19 Wh kg−1 when the power density is 849.94 W kg−1. It has unexpected application prospects.

Tailoring the bifunctional electrocatalytic activity of electrodeposited molybdenum sulfide/iron oxide heterostructure to achieve excellent overall water splitting

• MoS 2 /Fe 2 O 3 heterostructure was fabricated by facile two-step electrodeposition. • Alteration in duration of the deposition steps regulated the water splitting efficiency. • Substrate adsorption–desorption and charge transfer efficiency of the heterostructure varied with deposition duration. • Tailored MoS 2 /Fe 2 O 3 heterostructure outperformed water splitting activity of the state-of-the-art RuO 2 || Pt/C electrolyzer. Development of facile strategies to directly fabricate the noble-metal-free heterostructure on the conducting substrate and tailoring its electrocatalytic activity are crucial to achieve the superior overall water splitting activity. Herein, a series of MoS 2 /Fe 2 O 3 heterostructure was directly fabricated on nickel foam substrate by a facile two-step electrodeposition technique. The alteration in duration of the deposition steps regulated the physicochemical properties and water splitting efficiency of the resulting heterostructure. A correlative investigation of Tafel and Nyquist plot revealed that the substrate adsorption–desorption and charge transfer efficiency of the heterostructure varied owing to this alteration. The successful integration of Fe 2 O 3 with MoS 2 synergistically enhanced the electrocatalytic activity of the heterostructure and binder-free growth on conducting nickel foam (NF) helped it to achieve higher catalytic current density. The heterostructure obtained through 5 and 6 min long two-step electrodepositions (F5M6), showed superior bifunctional electrocatalytic activity. The symmetric cell constructed with F5M6 electrode outperformed the state-of-the-art RuO 2 || Pt/C electrolyzer at higher operating voltage region and was able to achieve a current density of 757 mA cm −2 at 2 V. Moreover, the heterostructure could sustain its overall water splitting proficiency for ~ 30 h at high current density confirming its excellent overall water splitting efficacy. This investigation established the two-step electrodeposition process as an effective electrocatalytic-activity-tailoring strategy.

Correlation between photoluminescence and photoelectrochemical properties of SrHPO4/ BaHPO4/FTO anode material

Abstract A new anode consisting of BaHPO4/SrHPO4 (SrP/BaP) micro-structured materials has been fabricated through two-step electrodeposition technique. Structural, vibrational, morphological, and optical properties of the anode films were investigated employing X-ray diffraction, Raman spectroscopy, scanning electron microscopy (SEM) and UV–Vis absorption spectroscopy, respectively. Photoluminescence (PL), and photo-electrocatalytic (PEC) activities of the samples were investigated and compared with those of the pure BaHPO4 (BaP) and SrHPO4 (SrP) samples. The PEC performance was of the order of 71% within 25 min, which was less than both BaP (99%) and SrP (92%) in the same experimental conditions. These results reveal that BaP thin films combined with SrP microstructures remarkably changed the PL signals, and in turn significantly enhanced the PL activities, while the PEC has been lowered down. This was attributed to the photo-induced electron–hole pairs recombination as electrochemical impedance spectrum and photo-current response have shown. Based on these results, it is believed that the SrP/BaP film behaves as a sensitizer in the system and not as a photo-electrocatalyst.

Fabrication of Nanorods-TiO2 for Heterojunction Thin Film Application with Electrodeposit-p-Cu2O Absorbing Layer

Abstract The TiO2 nanorod (TNRs) was synthesized on fluorine doped tin oxide (FTO) glass substrate using hydrothermal method. The TBOT concentration during hydrothermal process was optimized. Vertically aligned rutile-TNRs were grown on FTO substrate with average diameter of 150 nm and length of 3.5 µm. After that, Cu2O was successfully deposited on TNRs using new proposed method; two-step electrodeposition technique. The electrodeposited-Cu2O fills the narrow spaces between the TNRs and completely covered the TNRs to form TNRs/Cu2O heterojuncion.

Effect of two-step electrodeposited Cu–TiO2 nanocomposite coating on pool boiling heat transfer performance

In order to decrease the energy consumptions in energy conversion devices, boiling heat transfer augmentation is one of the important research activities for the scientific community. In present study, the pool boiling heat transfer characteristics of Cu–TiO2 composite coating on copper surfaces are reported. A two-step electrodeposition technique is employed to develop the nanocomposite coatings on copper surfaces, where higher current densities are applied for a short period and then the deposition is continued with lower current density for longer period in the second step of electrochemical deposition. The layer deposited during the first step is fragile, which is stabilized during the second step of electrodeposition at lower current density for longer duration. The surface morphology properties like porosity, wettability, coating layer thickness are easily controlled by managing the electrodeposition parameters like electrolyte composition, deposition time and current density. The pool boiling experiments are performed on bare and composite-coated surfaces at atmospheric pressure with saturated DI water. The boiling performance of coated surfaces is compared with the bare (uncoated) surface. The maximum boiling heat transfer coefficient and critical heat flux on coated surfaces are achieved to be 151 kW m−2 K−1 and 1988 kW m−2, which are 185% and 86% higher than the bare copper surface, respectively. The enhancement in boiling performance is associated with several parameters like increase in porosity, presence of high-density nucleation sites, and improvement in surface wettability.

Annealing effects on the microstructure, magnetism and microwave-absorption properties of Fe/TiO2 nanocomposites

To overcome the problems of Fe nanowires and obtain an outstanding material for the applications of magnetic recording and microwave absorption. Fe/TiO2 core/shell nanowire arrays were fabricated by a controllable two-step electrodeposition technique using anodic aluminum oxide (AAO) membrane as the template. The influences of annealing on the microstructure, magnetism and microwave-absorption properties of the arrays were studied. It was demonstrated experimentally that the partial crystallization of amorphous TiO2 and the polycrystalline structure of TiO2 originating from annealing enhanced the microwave-absorption properties of Fe/TiO2 core/shell nanowire arrays. We also found that the nanowire arrays with small diameter exhibited more obvious magnetic anisotropy. Our study shows that Fe/TiO2 core/shell nanowire arrays can be used for the applications of magnetic recording and microwave absorption.

Facile synthesis of hybrid manganese oxide and multiwalled carbon nanotube by two-step electrodeposition for supercapacitor electrode

This work presents a facile synthesis of hybrid manganese oxide and multiwalled carbon nanotube (MnOx/MWCNT) by two-step electrodeposition technique for supercapacitor electrode application. Firstly, MWCNT was deposited onto SS304 substrate by electrophoretic deposition at a constant voltage of 7 V for 5 min. MWCNT solution was prepared using sodium dodecylbenzenesulfonate (SBDS) as a surfactant. Next, MnOx was deposited onto the pre-deposited MWCNT/SS304 substrate by galvanostatic electrodeposition using 0.1 M manganese sulfate (MnSO4) solution as a precursor. The electrodeposition condition was set at a constant current of 1 mA/cm2 for 5-15 min. Nanosheet array of MnOx was formed uniformly on MWCNT. At the deposition time of 10 min, the thickness of MnOx nanosheet was approximately 40 nm. Hybrid MnOx/MWCNT was characterized its electrochemical properties by cyclic voltammetry, galvanostatic charge-discharge, and electrochemical Impedance spectroscopy. Hybrid MnOx/MWCNT shows an improved specific capacitance of 267.03 F·g-1 with a series resistance of 5.17 Ω, surpassing electrode material with only MnOx or MWCNT. The high specific capacitance would be ascribed to the integration of MWCNT and MnOx functions. MWCNT may act as a platform for MnOx deposition, resulting in an increase in electrochemically active surface area of MnOx. The obtained results indicate that this two-step electrodeposition method allows tailor-made hybrid materials with nanoscale control without using harsh and toxic chemicals or high synthesis temperature.

Fabrication of CdTe thin films grown by the two-step electrodeposition technique on Ni foils

In this paper, a two-step electrodeposition technique is adopted to prepare CdTe thin films on Ni foils from acidic solutions by a rapid and convenient electrodeposition method. In the first step, a Te-rich CdTe layer was deposited at −0.3V on a Ni foil substrate. Then on surface of this film, a second layer of CdTe was deposited at −0.6V. The two-step CdTe thin films show higher short-circuit current densities, suggesting potential application in solar cells, and the crystallinity of this film is also enhanced, as suggested by the sharpening of the corresponding CdTe peaks. The major change of the two-step film lies in the broader and stronger absorption intensity in the visible region, indicating that the CdTe thin film prepared by the two-step electrodeposition technique on Ni foils can extend the absorption active range of sunlight and improve the photovoltaic performance to visible light. The preliminary material growth and assessment results are presented.

Development of a two-step electrodeposition process for enhancing pool boiling

Abstract The continuous development of high performance chips and the growing miniaturization trend in the electronics and microelectronics industry require efficient systems to remove large amounts of heat over a small footprint. Pool boiling has the ability to remove large heat fluxes at small values of wall superheat and this can be further augmented by using porous or microporous surfaces. In this work, a two-step electrodeposition technique involving application of high current density for a short time, followed by a lower current density for a longer time was investigated. This technique allowed a close control of the pore size and porous layer thickness. The electrodeposition process was carefully studied and parameters for creating different morphologies of enhanced surfaces were obtained. Thickness of the coating was in range of 50–100 μm. After testing a variety of morphologies for pool boiling heat transfer with distilled water, a maximum heat flux of 1400 kW/m2 and a significant enhancement in heat transfer coefficient (HTC) of 179 kW/m2 °C was obtained from a copper chip with cauliflower-like morphology using an initial current density of 400 mA/cm2.

A highly sensitive non-enzymatic glucose sensor based on a simple two-step electrodeposition of cupric oxide (CuO) nanoparticles onto multi-walled carbon nanotube arrays

A novel, stable and highly sensitive non-enzymatic glucose (Glc) sensor was developed using vertically well-aligned multi-walled carbon nanotubes array (MWCNTs) incorporated with cupric oxide (CuO) nanoparticles. The MWCNTs array was prepared by catalytic chemical vapor deposition on a tantalum (Ta) substrate, while a simple and rapid two-step electrodeposition technique was used to prepare the CuO–MWCNTs nanocomposite. First, Cu nanoparticles were deposited onto MWCNTs at constant potential and then they were oxidized into CuO by potential cycling. The electrocatalytic activity of CuO–MWCNTs array was investigated for Glc under alkaline conditions using cyclic voltammetry and chronoamperometry. The sensor exhibited a linear response up to 3 mM of Glc and sensitivity of 2190 μA mM −1 cm −2, which is two to three orders of magnitude higher than that of most non-enzymatic Glc sensors reported in the literature. The sensor response time is less than 2 s and detection limit is 800 nM (at signal/noise = 3). When tested with human blood serum samples, the sensor exhibited high electrocatalytic activity, stability, fast response and good selectivity against common interfering species, suggesting its potential to be developed as a non-enzymatic Glc sensor.

Growth of highly oriented ZnO films by the two-step electrodeposition technique

Compact and transparent ZnO films were deposited on the ITO/glass substrates from zinc nitrate aqueous solution by the two-step electrodeposition technique. While the first potentiostatic step was used to produce ZnO seed layer, the ZnO film growth has been done galvanostatically. Effects of the potentiostatic parameters on the crystal structure, morphology and optical properties of ZnO films were investigated. Results show that ZnO films with highly c-axis preferred orientation can been obtained when the potentiostatic deposition at −1.2 V for 15 s has been applied. Such an observation might be attributed to the etching process of ITO substrate in the diluted HCl solution. The film exhibits smooth and compact morphology, high transmittance in the visible band (>80%) and sharp absorption edge (at ∼370 nm). The analysis on the growth mechanism indicates that the short potentiostatic process prior to the film growth can produce ZnO seed layer and substitute the initial nucleation process in the conventional one-step galvanostatic deposition, thus increasing the nucleation density and preventing the formation of loose structures.

Electrodeposition and characterization of CdTe thin films on Mo foils using a two voltage technique

Polycrystalline thin film CdTe-based solar cells are one of the most promising candidates for low-cost terrestrial conversion of solar energy because of the optimum energy band gap ( E g =1.44 eV ) and high absorption coefficient of CdTe. In this work, a two-step electrodeposition technique has been used to prepare CdTe thin films from acidic solutions. In the first step, a thin Te rich CdTe layer was deposited at –300 mV (SCE) on a Mo foil substrate. On top of this film, a Cd rich CdTe layer was deposited at more negative voltages. The resulting films showed good adherence to the substrate and very low contact resistance between the substrate and the p+ Te rich CdTe layer. The composite film was of nearly stoichiometric composition. From X-ray diffraction results, the as-deposited films show very small grain sizes but after annealing the grain size increases considerably showing very well-defined peaks. The morphological, structural and composition results of CdTe thin films obtained by Scanning Electron microscopy, X-ray diffraction, and X-ray fluorescence will be presented. Electrical properties such as conductivity type and contact resistance values for the Mo/CdTe structures will also be presented.