Template Electrodeposition Research Articles

Electrodeposition of bismuth, tellurium and bismuth telluride through sub-10 nm mesoporous silica thin films

Templated electrodeposition is an efficient technique for the bottom-up fabrication of nanostructures and can effectively control the size and shape of the electrodeposits. Here, mesoporous silica thin films with highly ordered mesopores and a regular three-dimensional mesostructure were synthesised as templates for electrodeposition. The mesoporous silica films have small mesopores (∼8 nm) and complex mesopore channels (Fmmm mesostructure with the [0 1 0] axis perpendicular to the substrate). Electrodeposition of bismuth, tellurium and bismuth-tellurium was investigated from electrolytes containing [NnBu4][BiCl4], [NnBu4]2[TeCl6] and [NnBu4]Cl dissolved in dry dichloromethane. Top-view SEM images showed Bi, Te and Bi doped-Te nanoparticles in the mesopores and cross-section SEM showed there were a few Te nanowires, in addition to the particle aggregations on the surface. This is a promising observation as it demonstrates the possibility of preparing sub-10 nm nanowires by templated electrodeposition even though the deposits are not uniformly electrodeposited in all the mesopores. EDX shows the deposited Bi-Te nanoparticles were tellurium-rich, XRD shows they were trigonal tellurium (ICSD 65692). A variety of parameters including the choice of pulsed electrodeposition conditions and [NnBu4][BiCl4] concentration (2.25 mM and 3 mM) were investigated in order to control the composition of the deposit. All samples prepared by pulsed electrodeposition showed very low Bi:Te ratio (Bi/Te<0.02), whereas samples deposited for 5 min at −0.6 V achieved high Bi content (Bi/Te=0.49).

Ultrafast fabrication of porous NF/Ni for water splitting in alkaline media

In this study, a rapid hydrogen-bubble template electrodeposition method was employed to synthesize a dual-functional catalyst (NF/Ni) for alkaline water splitting. Physical characterization revealed that a coarsened NF/Ni with a porous structure was obtained, providing an enlarged surface area. In addition, it revealed that the CV activation is beneficial to the formation of Ni-Ni(OH)2 coupling interface, which is responsible for reducing of water dislocation energy barrier and providing a balanced H adsorption energy on the Ni site. Consequently, the overpotential of oxygen/hydrogen evolution reaction at 10 mA cm−2 is 290 and 71 mV. In-situ Raman spectroscopies confirm that the generated NiOOH serves as the active center for OER process. When assembled to a two-electrode cell, it showed a cell voltage of 1.62 V@10 mA cm−2, which was 160 mV lower than that of NF‖NF. Furthermore, the university study confirms the formation of hydroxide on the surface of the metal is beneficial to boosting the hydrogen evolution activity.

Site-selective core/shell deposition of tin on multi-segment nanowires for magnetic assembly and soldered interconnection

The field of nanotechnology continues to grow with the ongoing discovery and characterization of novel nanomaterials with unconventional size-dependent properties; however, the ability to apply modern manufacturing strategies for practical device design of these nanoscale structures is significantly limited by their small size. Although interconnection has been previously demonstrated between nanoscale components, such approaches often require the use of expensive oxidation-resistant noble metal materials and time-consuming or untargeted strategies for welded interconnection such as laser ablation or plasmonic resonance across randomly oriented component networks. In this work, a three-segment gold–nickel–gold nanowire structure is synthesized using templated electrodeposition and modified via monolayer-directed aqueous chemical reduction of tin solder selectively on the gold segments. This core/shell nanowire structure is capable of directed magnetic assembly tip-to-tip and along substrate pads in network orientation. Upon infrared heating in a flux vapor atmosphere, the solder payload melts and establishes robust and highly conductive wire–wire joints. The targeted solder deposition strategy has been applied to various other multi-segment gold/nickel nanowire configurations and other metallic systems to demonstrate the capability of the approach. This core/shell technique of pre-loading magnetically active nanowires with solder material simplifies the associated challenges of size-dependent component orientation in the manufacture of nanoscale electronic devices.

Gold nanowires-based sensor for quantification of H2O2 released by human airway epithelial cells

Hydrogen peroxide (H2O2) is a biomarker relevant for oxidative stress monitoring. Most chronic airway diseases are characterized by increased oxidative stress. To date, the main methods for the detection of this analyte are expensive and time-consuming laboratory techniques such as fluorometric and colorimetric assays. There is a growing interest in the development of electrochemical sensors for H2O2 detection due to their low cost, ease of use, sensitivity and rapid response. In this work, an electrochemical sensor based on gold nanowire arrays has been developed. Thanks to the catalytic activity of gold against hydrogen peroxide reduction and the high surface area of nanowires, this sensor allows the quantification of this analyte in a fast, efficient and selective way. The sensor was obtained by template electrodeposition and consists of gold nanowires about 5 μm high and with an average diameter of about 200 nm. The high active surface area of this electrode, about 7 times larger than a planar gold electrode, ensured a high sensitivity of the sensor (0.98 μA μM−1cm−2). The sensor allows the quantification of hydrogen peroxide in the range from 10 μM to 10 mM with a limit of detection of 3.2 μM. The sensor has excellent properties in terms of reproducibility, repeatability and selectivity. The sensor was validated by quantifying the hydrogen peroxide released by human airways A549 cells exposed or not to the pro-oxidant compound rotenone. The obtained results were validated by comparing them with those obtained by flow cytometry after staining the cells with the fluorescent superoxide-sensitive Mitosox Red probe giving a very good concordance.

Amorphous Sb2Te3 nanowires: Synthesis, characterization and size-dependent phase transition behavior

Understanding the phase transition behavior of phase-change (PC) material with respect to the scaling effect is essential for the application of PC materials. Among all the PC materials, SbTe binary plays a significant role in the well-known Ge-Sb-Te system. Here we have used an unconventional and cost-effective method to fabricate a wide range of prototypical Sb2Te3amorphous nanowires (18–220 nm in diameter) using templated electrodeposition. Compositional, morphological, and structural characterization of the amorphous nanowires were performed, and the crystallization temperature of in-template nanowires was measured using a four-probe resistivity meter. We report that the crystallization temperature of amorphous Sb2Te3 nanowires can be tuned with respect to the diameter of the nanowires and a significant increase was observed for the nanowires with diameters ≤35 nm. Our study sheds light on the size-dependent phase transition behavior of PC NWs with implications for further advancement of the PC memory technology.

Electrocatalytic Degradation of Acyclovir by Three-Dimensional Porous Lead Dioxide Anodes: Condition Optimization, Kinetic Analysis and Degradation Mechanisms

A three-dimensional porous lead dioxide electrode (3D-PbO2) was developed by the template electrodeposition approach. Polystyrene microspheres were prepared by microemulsion polymerization, and then the polystyrene template was loaded on the PbO2 electrode by electrodeposition. Finally, a porous structure was formed by removing the template. Under these optimized conditions, the degradation of acyclovir could achieve complete removal, while the removal of COD was 29.59%. The electrochemical degradation process of acyclovir was consistent with the proposed primary reaction kinetics. The 3D-PbO2 electrode was comprehensively characterized using SEM, XRD, and XPS techniques. The SEM analysis revealed the presence of well-defined porous structures on the electrode surface, while the XRD results indicated a reduction in electrode crystal sizes. Additionally, the XPS analysis demonstrated a higher proportion of reactive oxygen species on the 3D-PbO2 electrode. The electrochemical properties of the electrode were investigated using CV and EIS. The experimental findings demonstrate that the 3D-PbO2 electrode exhibits a higher oxygen evolution potential and lower charge transfer resistance than the conventional PbO2 electrode. This study presents a viable approach to enhance the electrochemical oxidation performance of lead dioxide.

Evolution of morphology and grain structure of metal nanowires in initial period of templated electrodeposition

Evolution of morphology and grain structure of metal nanowires in initial period of templated electrodeposition

Geometrical recognition of metallic foam microstructures using a deep learning approach

The geometric characteristics of nanostructured porous metallic foams (NMFs) impact their properties, enabling applications in electrocatalysis, energy conversion, and energy storage. The morphology of these three-dimensional (3D) structures is complex, in large part, because of their complicated formation mechanisms. This work presents a computational strategy for geometrically characterizing different NMFs designs. Three types of samples were synthesized using the dynamic hydrogen bubble template electrodeposition method. A set of microscopic confocal images of NMFs was used as training input samples. Herein, a variational autoencoder (VAE) was adjusted under a pretext task, allowing learning embedding descriptors to represent the geometry of microscopic observations. To evaluate the feasibility of using a VAE to assist in the classification of NMFs, a set of machine learning classifiers was implemented to discriminate among the groups of embedded vectors according to their classes. Furthermore, the capacity of the VAE was validated regarding the capability to separate the vectors according to their classes. Explainability mechanisms stand out geometrical features of input images that had major support during the classification task.

Monitoring of Pore Orientation by in Operando Grazing Incidence Small-Angle X-ray Scattering during Templated Electrodeposition of Mesoporous Pt Films.

We have used in operando grazing incidence small-angle X-ray scattering (GISAXS) to monitor structural changes during templated electrodeposition of mesoporous platinum films on gold electrodes from a ternary lyotropic liquid crystalline mixture of aqueous hexachloroplatinic acid and the diblock copolymer surfactant Brij56. While the cylindrical micelles of the lyotropic liquid crystal (LLC) in the hexagonal phase have a center-to-center distance of 7.5 nm with a preferential alignment parallel to the electrode surface, the electrodeposited platinum films contain highly ordered mesopores arranged in a 2D hexagonal structure, with a center-to-center distance of about 8.5 nm and a preferential orientation perpendicular to the electrode surface. The progression of structural changes of the LLC template and the deposited mesoporous Pt could be monitored for the first time in operando by GISAXS: within the first 14 s of deposition, a nucleation burst of Pt coincides with a loss of preferential alignment of the LLC. Initially, the morphology of the 2-dimensionally nucleated Pt replicates the Au substrate. During the following 5 to 7 min, the growth morphology of the Pt film changes, and vertically aligned mesopores form. Our results indicate mutual interaction between the species involved in the electrodeposition and the LLC template, leading to a partial loss of horizontal orientation of the LLC during Pt nucleation before vertical rearrangement of the micelles to the electrode surface. The vertically aligned mesopores in the Pt and the possibility to produce freestanding films make these materials interesting in fields such as electrocatalysis, energy harvesting, and nanofluidics.

Photothermal superhydrophobic copper nanowire assemblies: fabrication and deicing/defrosting applications

Ice and frost buildup continuously pose significant challenges to multiple fields. As a promising de-icing/defrosting alternative, designing photothermal coatings that leverage on the abundant sunlight source on the earth to facilitate ice/frost melting has attracted tremendous attention recently. However, previous designs suffered from either localized surface heating owing to the limited thermal conductivity or unsatisfied meltwater removal rate due to strong water/substrate interaction. Herein, we developed a facile approach to fabricate surfaces that combine photothermal, heat-conducting, and superhydrophobic properties into one to achieve efficient de-icing and defrosting. Featuring copper nanowire assemblies, such surfaces were fabricated via the simple template-assisted electrodeposition method, allowing us to tune the nanowire assembly geometry by adjusting the template dimensions and electrodeposition time. The highly ordered copper nanowire assemblies facilitated efficient sunlight absorption and lateral heat spreading, resulting in a fast overall temperature rise to enable the thawing of ice and frost. Further promoted by the excellent water repellency of the surface, the thawed ice and frost could be spontaneously and promptly removed. In this way, the all-in-one design enabled highly enhanced de-icing and defrosting performance compared to other nanostructured surfaces merely with superhydrophobicity, photothermal effect, or the combination of both. In particular, the defrosting efficiency could approach ∼100%, which was the highest compared to previous studies. Overall, our approach demonstrates a promising path toward designing highly effective artificial deicing/defrosting surfaces.

Microstructure and Properties of Porous Copper Foils with High Specific Surface Area Prepared by Electrodeposition

The high surface area porous copper foils are synthesized on commercial copper foils by dynamic hydrogen bubble template electrodeposition method. The electrochemical deposition mechanism of porous copper foils and the current density on the structure formation mechanism are explored. The results show that under the conditions of stable electrolyte, electrodeposition time of 20 s, and current density of 2 A·cm−2, the microporous distribution of the deposited layer is uniform and the adhesion between the pore walls is strong. Compared with the planar copper foil, the porous copper foil possesses the “large on top and small on bottom” porous structure, which significantly improves the specific surface area of the copper foil, and the resistance value decreases by 43.1%. The electrochemical test results show that the performance of the porous collector is significantly better than that of the planar collector. Furthermore, the porous copper collector has a lower charge transfer impedance (150 Ω). The results of this paper provide an innovative strategy for the preparation of porous collectors and for solving the problem of lithium metal batteries.

Construction of an electrode with hierarchical three-dimensional NiFe-oxyhydroxides by two-step electrodeposition for large-current oxygen evolution reaction

Oxygen evolution reaction (OER) electrocatalysts are promised to be extremely important in hydrogen generation of water electrolysis as one of the renewable energy technologies. However, low efficiency and high cost are two crucial barriers that hinder its development and application. Herein, we developed highly efficient NiFe-based self-supported electrocatalysts by a facile two-step electrodeposition method focusing on the porosification of a nickel foam (NF) substrate. The porous nickel layer (PN/NF) formed in the first step by dynamic hydrogen bubble template electrodeposition proved to be effective in facilitating the mass transfer process, and the following second step of nickel-iron deposition (NiFe/PN/NF) continued to increase the intrinsic catalytic activity, with the two synergistically contributing to the excellent OER performance. As an oxygen evolution electrode, it exhibits high catalytic activity in alkaline water electrolysis, which requires only an overpotential of 211 mV to promote the oxidation reaction of water. The overpotentials for the OER at 100, 500 and 750 mA cm−2 are as low as 244, 297 and 326 mV in 1 M KOH, respectively. In 6 M KOH, the overpotentials for driving electrolytic oxygen production at 100, 500, 750 and 1000 mA cm−2 are even lowered spectacularly to 133 mV, 178 mV, 193 mV and 208 mV, respectively. In particular, the catalyst showed a catalytic stability of more than 40 h at a current density of 500 mA cm−2, which presents it as a highly promising candidate for future large-scale industrial applications.

A sequential template electrodeposition anodization and in situ aniline electropolymerization-based facile electrochemical synthesis strategy

Herein, we propose a facile continuous electrochemical synthesis strategy to build 3D hierarchical hybrid conductive networks based on sequential template electrodeposition-anodization and in-situ aniline electropolymerization. It was implemented in a tin system to prepare a 3D tin skeleton with micron-scale features using the hydrogen bubble dynamic template method, followed by electrochemical anodization to achieve nanoscale modulation. This well-designed 3D hierarchical metal oxide framework was used for the in-situ electropolymerization of aniline, preserving the hierarchical morphological features while establishing large conductive networks for ultrafast electron transport and enhancing the structural stability of tin dendrites. Regulation of the hierarchical morphologies promotes material surface reactivity, increases the electrochemically active sites, and improves the ion diffusion kinetics, thus solving the “dead surface” problem in the energy storage process. Such multifaceted synergistic strategies of structural modulation and functional hybridization have opened up new ways to design efficient binder-free hybrid electrode materials.

Metal-organic framework-derived S-NiFe PBA coupled with NiFe layered double hydroxides as Mott-Schottky electrocatalysts for efficient alkaline oxygen evolution reaction

Development of economical and high-efficient catalytic electrodes is a top priority for oxygen evolution reactions (OER). Non-precious metal based metal–organic frameworks (MOFs) in powder form remain a series of problems including the assistance of adhesive, poor conductivity and stability. Herein, a well-designed S-NiFe PBA@NiFe/NF composite with a unique Mott-Schottky heterojunction architecture was purposefully constructed by self-sacrificing template approach and electrodeposition. The growth of S-NiFe PBA@NiFe on NF through in situ synthesis promotes efficient electron conduction between the NF substrate and S-NiFe PBA@NiFe catalyst, leading to a stable and highly effective working state. The Mott-Schottky heterojunctions between S-NiFe PBA and NiFe-layered double hydroxides (LDH) effectively expedite electronic transmission. Consequently, S-NiFe PBA@NiFe/NF exhibits outstanding OER behavior at 1.0 M KOH, exhibiting a low Tafel slope of 39 mV dec−1 and at 10 mA cm−2, reaching an unexpectedly low overpotential of 196.7 mV. Furthermore, the S-NiFe PBA@NiFe/NF maintains long-term durability without evident performance degradation for 100 h.

Design and Evaluation of Composite Magnetic Iron-Platinum Nanowires for Targeted Cancer Nanomedicine.

The purpose of the study was to synthesize and investigate the influence of geometrical structure, magnetism, and cytotoxic activity on core-shell platinum and iron-platinum (Fe/Pt) composite nanowires (NWs) for potential application in targeted chemotherapeutic approaches. The Pt-NWs and Fe/Pt composite NWs were synthesized via template electrodeposition, using anodic aluminum oxide (AAO) membranes. The Fe/Pt composite NWs (Method 1) was synthesized using two electrodeposition steps, allowing for greater control of the diameter of the NW core. The Fe/Pt composite NWs (Method 2) was synthesized by pulsed electrodeposition, using a single electrolytic bath. The properties of the synthesized NWs were assessed by high-resolution transmission electron microscopy (HRTEM), Raman spectroscopy, powder X-ray diffraction (XRD), inductively coupled plasma-optical emission spectrometry (ICP-OES), vibrating-sample magnetometry (VSM), and surface charge (zeta potential). A microscopy image analysis of the NWs revealed the presence of high-aspect-ratio NWs with nominal diameters of 40-50 nm and lengths of approximately <4 µm. The obtained powder XRD patterns confirmed the presence of a polycrystalline structure for both Pt NWs and Fe/Pt composite NWs. The potential utility of the synthesized NW nanoplatforms for anticancer activity was investigated using Tera 1 cells and Mouse 3T3 cells. Pt-NWs displayed modest cytotoxic activity against Tera 1 cells, while the Fe/Pt composite NWs (both Methods 1 and 2) demonstrated enhanced cytotoxic activity compared to the Pt-NWs on Tera 1 cells. The Fe/Pt composite NWs (Method 1) displayed ferromagnetic behavior and enhanced cytotoxic activity compared to Pt-NWs on Tera 1 cells, thus providing a sound basis for future magnetically targeted chemotherapeutic applications.

Synthesis of Cu Nanowires by Template Electrodeposition and Their Application in Pressure Sensors

Synthesis of Cu Nanowires by Template Electrodeposition and Their Application in Pressure Sensors

Template-assisted electrodeposition of metals: A method for determining the fraction of active nanopores

Template-assisted electrodeposition is a versatile technique for preparing metal nanostructures, e.g. nanowires and nanotubes, in anodic aluminium oxide (AAO) templates with cylindrical channels. However, the fraction of pores in which the electrochemical process occurs is not known in advance, which makes coulometric control of the deposition process nontrivial. In this paper, we propose a simple method for determining the fraction of active nanopores, i.e., pores in which metal is deposited. This is based on the analysis of current transients registered during templated electrodeposition. The developed method makes it possible to estimate the density of deposited nanowires and their average length by coulometric control without using scanning electron microscopy.

Convenient construction of porous dendritic Cu-doped Ni@PPy/stainless steel mesh electrode for oxidation of methanol and urea

In multifunctional catalysts, Ni-based alloys and compounds can be used for methanol oxidation reaction (MOR) and urea oxidation reaction (UOR). Herein, the porous dendritic NiCu@PPy/316L stainless steel mesh (SSM) electrode is prepared by dynamic hydrogen bubble template electrodeposition, followed by cyclic voltammetry electrodeposition of polypyrrole (PPy) conductive polymer on the electrode surface. Among them, dynamic hydrogen bubbles successfully assisted the formation of porous structures in the Ni-based deposition layer. In addition, the morphology of the resulting Ni-based layer further evolves from particle stacking to dendritic with high specific surface area with Cu doping. Eventually, 2-NiCu/SSM achieves current densities of 294.5 mA·cm−2 (MOR) and 278.6 mA·cm−2 (UOR) at 0.8 V, respectively. The PPy coating prevents the agglomeration of NiCu particles in the catalytic layer and further improves the persistence of the electrochemical performance. After 2000 cycles, the current densities of 2-NiCu @PPy/SSM in the new electrolyte are maintained at 89.1% (MOR) and 94.8% (UOR) of the original value, with a 10% increase for MOR and a 7% increase for UOR compared to the sample without PPy coating (2-NiCu /SSM).

A Comparison between Porous to Fully Dense Electrodeposited CuNi Films: Insights on Electrochemical Performance.

Nanostructuring of metals is nowadays considered as a promising strategy towards the development of materials with enhanced electrochemical performance. Porous and fully dense CuNi films were electrodeposited on a Cu plate by electrodeposition in view of their application as electrocatalytic materials for the hydrogen evolution reaction (HER). Porous CuNi film were synthesized using the hydrogen bubble template electrodeposition method in an acidic electrolyte, while fully dense CuNi were electrodeposited from a citrate-sulphate bath with the addition of saccharine as a grain refiner. The prepared films were characterized chemically and morphologically by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), and X-ray diffraction (XRD). The Rietveld analysis of the XRD data illustrates that both CuNi films have a nanosized crystallite size. Contact angle measurements reveal that the porous CuNi film exhibits remarkable superhydrophobic behavior, and fully dense CuNi film shows hydrophilicity. This is predominately ascribed to the surface roughness of the two films. The HER activity of the two prepared CuNi films were investigated in 1 M KOH solution at room temperature by polarization measurements and electrochemical impedance spectroscopy (EIS) technique. Porous CuNi exhibits an enhanced catalysis for HER with respect to fully dense CuNi. The HER kinetics for porous film is processed by the Volmer-Heyrovsky reaction, whereas the fully dense counterpart is Volmer-limited. This study presents a clear comparison of HER behavior between porous and fully dense CuNi films.

Dynamic hydrogen bubble template electrodeposited Bi on graphite felt and the effect of its post-processing in vanadium redox flow batteries

Dynamic hydrogen bubble template (DHBT) electrodeposition is an efficient synthesis method in decorating graphite felts with high surface area bismuth nanoparticles as the electrochemically active negative electrode in vanadium redox flow batteries.