Template-assisted Electrodeposition Research Articles

Preparation of a flexible polypyrrole nanoarray and its capacitive performance

Polypyrrole nanotube embedded nanopore array (PNENA) was prepared using an independent TiO2 nanotube array template-assisted electrodeposition and template removal process. All polypyrrole nanotubes were fully embedded inside polypyrrole nanopores to form a coaxial nanoarray structure and flow-through characteristic. The PNENA thin film electrode exhibited a specific capacitance of 88.6Fg−1 in a potential range of −0.2–0.6V and a capacity retention of 67% after the 1000 cycles in 1.0M H2SO4 aqueous solution. A solid-state flexible PNENA supercapacitor was assembled using two symmetric PNENA electrodes and gel electrolyte, showing a specific capacitance of 13Fg−1 at a current density of 0.005Ag−1. This PNENA supercapacitaor also exhibited a stable capacitive performance at both planar state and bending state, showing its possibility for flexible energy storage.

Bi2Se3/Bi multiple heterostructure nanowire arrays formed by pulsed electrodeposition

Thermoelectric Bi2Se3/Bi multilayered nanowire arrays with a minimum period of about 100nm were first successfully fabricated by a template-assisted pulsed electrodeposition process. And the effect of ion concentration on electrodeposition current was investigated by using the cyclic voltammogram. Meanwhile, the nanowires were characterized by X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, high resolution transmission electron microscopy, and energy dispersive X-ray spectroscopy, respectively. Large-scale and continuous nanowire arrays with multi-segment characters and uniform diameters can be observed by FE-SEM and TEM, and the randomly selected neighboring segments were characterized to be Bi2Se3 and Bi, respectively, by EDS.

Synthesis and characterization of gold nanotube/nanowire–polyurethane composite based on castor oil and polyethylene glycol

Gold nanotubes/nanowires (GNT/NW) were synthesized by using the template-assisted electrodeposition technique and mixed with castor oil–polyethylene glycol based polyurethane (PU) to fabricate porous composite scaffolds for biomedical application. 100 and 50ppm of GNT/NW were used to synthesize composites. The composite scaffolds were characterized by Fourier transform infrared spectroscopy, dynamic mechanical thermal analysis, differential scanning calorimetry, and scanning electron microscopy. Cell attachment on polyurethane–GNT/NW composites was investigated using fat-derived mesenchymal stem cells. Addition of 50 or 100ppm GNT/NW had significant effects on thermal, mechanical, and cell attachment of polyurethane. Higher crosslink density and better cell attachment and proliferation were observed in polyurethane containing 50ppm GNT/NW. The results revealed that GNT/NW formed hydrogen bonding with the polyurethane matrix and improved the thermomechanical properties of nanocomposites. Compared with pure PU, better cellular attachment on polyurethane–GNT/NW composites was observed resulting from the improved surface properties of composites.

Quinary PdNiCoCuFe Alloy Nanotube Arrays as Efficient Electrocatalysts for Methanol Oxidation

Multi-metallic alloy nanotube arrays are highly favorable for superior electrocatalytic performance and efficient utilization of catalyst because of the special characteristics of alloys, hollow nanotubes, and array nanostructures. Here we firstly prepared the quinary PdNiCoCuFe alloy nanotube arrays (NTAs) by template-assisted electrodeposition method. The inner diameters, wall thicknesses, and lengths of PdNiCoCuFe alloy nanotubes are 300∼400nm, 150nm, and 1.8μm, respectively. Because of the high specific surface area, hollow nanotube arrays, and synergistic effects of various elements, the quinary PdNiCoCuFe alloy NTAs as efficient electrocatalysts showed superior catalytic activity and long-term cycle stability for methanol electrooxidation. The combination of compositionally and geometrically favorable factors provides a new method to design the novel catalysts with excellent electroactivity and durability.

Carbon/MnO2Double-Walled Nanotube Arrays with Fast Ion and Electron Transmission for High-Performance Supercapacitors

The novel carbon (C)/MnO2 double-walled nanotube arrays (DNTAs) are designed and fabricated via template-assisted electrodeposition. The unique DNTA architectures of C/MnO2 composites with high weight fraction of MnO2 allow high electrode utilization ratio and facilitate electron and ion transmission. In the half-cell test, the hybrid C/MnO2 DNTAs as electrodes show a large specific capacitance (Csp) of 793 F/g at the scan rate of 5 mV/s, high energy/power densities, and much enhanced long-term cycle stability. After 5,000 cycles, the Csp retention of C/MnO2 DNTAs keeps ∼97%, which is much larger than 69% of the MnO2 nanotube arrays (NTAs). The symmetrical supercapacitors (SSCs) composed of C/MnO2 DNTAs also show the predominant performance, such as large Csp of 161 F/g and high energy density of ∼35 Wh/kg, indicating that the C/MnO2 DNTAs is a potential electrode for supercapacitors. The high order pore passages, double-walled structures, hollow structures, and high conductivity are responsible for the superior performance of C/MnO2 DNTAs. Such hybrid C/MnO2 DNTAs may bring new opportunities for the development of supercapacitors with superior performance.

Fabrication of bowl-like porous WO3 film by colloidal crystal template-assisted electrodeposition method

Large scale of bowl-like porous WO3 film was successfully fabricated by electrodeposition into two-dimensional (2D) polystyrene (PS) colloidal crystal template. The technological process involved the following steps: colloidal crystal template preparation, potentiostatic electrodeposition of WO3 into the template, and template removal. 1.5 μm PS spheres were used to prepare the 2D colloidal crystal template by means of spinning on indium-tin-oxide (ITO) glass. A two-electrode cell was used for electrodeposition, in which the anode was graphite and the cathode was PS-coated ITO glass. The electrodeposition solution consisted of 25 mM Na2WO4 and 30 % H2O2 acidified at pH 1.2. Via electrodeposition, the interstitial space of the densely packed PS colloidal crystal template was filled with WO3. Bowl-like porous WO3 film was obtained after the removal of the PS colloidal crystal template by a thermal treatment at 475 °C. Scanning electron microscopic, X-ray diffraction spectra and transmission electron microscopy were performed to analyze and compare bowl-like porous WO3 film with dense WO3 film. The homogeneous area of the obtained film was 25 × 15 mm2. The template-assisted electrodeposition method was simple and low-cost that can be completed within 30 min.

Synthesis of Silicon and Germanium Nanowire Assemblies by Template-Assisted Electrodeposition from an Ionic Liquid

We report on the template-assisted synthesis of silicon and germanium nanowires from the air- and water-stable ionic liquid, 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)amide ([Py1,4] TFSA). The synthesis was done by electrochemical deposition in the pores of a commercial track-etched polycarbonate membrane. After chemical dissolution of the polycarbonate membrane in dichloromethane, nanowire assemblies with a regular arrangement were obtained. Different lengths of nanowires can be obtained by varying the applied potential and the time of deposition. The nanowire assemblies were characterised by scanning electron microscopy and energy-dispersive X-ray spectroscopy (SEM/EDX). Our results show that the template-assisted electrochemical deposition approach in ionic liquids has the potential to easily synthesise germanium and silicon nanowire assemblies.

Electrochemical preparation of vertically aligned, hollow CdSe nanotubes and their p-n junction hybrids with electrodeposited Cu2O.

Vertically aligned, hollow nanotubes of CdSe are grown on fluorine doped tin oxide (FTO) coated glass substrates by ZnO nanowire template-assisted electrodeposition technique, followed by selective removal of the ZnO core using NH4OH. A detailed mechanism of nucleation and anisotropic growth kinetics of nanotubes have been studied by a combination of characterization tools such as chronoamperometry, SEM and TEM. Interestingly, "as grown" CdSe nanotubes (CdSe NTs) on FTO coated glass plates behave as n-type semiconductors exhibiting an excellent photo-response (with a generated photocurrent density value of ∼ 470 μA cm(-2)) while in contact with p-type Cu2O (p-type semiconductor, grown separately on FTO plates) because of the formation of a n-p heterojunction (type II). The observed photoresponse is 3 times higher than that of a similar device prepared with electrodeposited CdSe films (not nanotubes) and Cu2O on FTO. This has been attributed to the hollow 1-D nature of CdSe NTs, which provides enhanced inner and outer surface areas for better absorption of light and also assists faster transport of photogenerated charge carriers.

Hierarchical NiCo2O4nanosheets@hollow microrod arrays for high-performance asymmetric supercapacitors

Novel NiCo2O4NSs@HNRAs are fabricatedviaa simple and environmental friendly template-assisted electrodeposition followed by thermal annealing and they exhibit predominant electrochemical properties and long-term cycle stability.

Role of boric acid in nickel nanotube electrodeposition: a surface-directed growth mechanism.

Nickel nanotubes have been synthesized by the popular and versatile method of template-assisted electrodeposition, and a surface-directed growth mechanism based on the adsorption of the nickel-borate complex has been proposed.

Fabrication of Nanoporous Nickel Coatings by Template-Assisted Electrodeposition

A nickel for the porous? Porous nickel coatings in form of spheres and nanotubes are synthesized through electrochemical deposition by using different templates and certain electrochemical potentials. These hierarchically ordered nanostructures have potential application as building blocks for electrochemical devices, such as current collectors for energy storage.

Electrochemical synthesis of freestanding tin nanowires from ionic liquids

In this article, we report on the electrodeposition of tin nanowire arrays from two different ionic liquids, namely, 1-ethyl-3-methylimidazolium dicyanamide ([EMIm]DCA) and 1-butyl-1-methylpyrrolidinium dicyanamide ([Py1,4]DCA). Tin nanowires were synthesized via a template-assisted electrodeposition process using polycarbonate membranes as templates. Gold or copper thin films were sputtered on one side of the track-etched polycarbonate template to make it conductive to be used as a working electrode. In order to have a thicker supporting layer, the electrodeposition process was done in two different ways; the first way was the deposition of Sn on both sides of the membrane, but Sn forms dendrites on the sputtered side so it cannot be used as a supporting layer for the synthesized nanowires. In the second way, Sn nanowires were deposited first through the nonsputtered side in the first step; then, a copper layer was deposited on the sputtered side in another step from 1 M CuCl/[EMIm]DCA.

Self-formed platform for in situ measurement of electrical transport of individual copper nanowires

Exploring electrical transport in a single individual nanowire provides unique opportunities to fundamental research and practical applications in nanowire-based electronics as well as energy applications. However, measuring such electrical transport in an individual nanowire generally involves nanowire release process followed by electrode patterning steps, which are difficult and tedious tasks. We demonstrate a simple in situ method for rapid measurement of the electrical transport in a single individual copper nanowire that is grown by template-assisted electrodeposition method. By depositing a thin metal layer on top of the nanowire template, a single individual nanowire circuit can be easily formed in situ by self-limiting the growth of other entire nanowires that are not connected, thereby creating a single individual nanowire contact. The measurement results are shown to be reliable, with average electrical resistivity value of 3.55μΩ·cm, which is in a good agreement with theoretical value. We also show that this method is superior to oxidation due to the in situ measurement environment. This self-formed platform not only shows a convenient method for transport property measurement, but it also suggests a possible utilization to future single nanowire-based applications.

Synthesis of copper telluride nanowires using template-based electrodeposition method as chemical sensor

Copper telluride (CuTe) nanowires were synthesized electrochemically from aqueous acidic solution of copper (II) sulphate (CuSO4·5H2O) and tellurium oxide (TeO2) on a copper substrate by template-assisted electrodeposition method. The electrodeposition was conducted at 30 °C and the length of nanowires was controlled by adjusting deposition time. Structural characteristics were examined using X-ray diffraction and scanning electron microscope which confirm the formation of CuTe nanowires. Investigation for chemical sensing was carried out using air and chloroform, acetone, ethanol, glycerol, distilled water as liquids having dielectric constants 1, 4·81, 8·93, 21, 24· 55, 42·5 and 80·1, respectively. The results unequivocally prove that copper telluride nanowires can be fabricated as chemical sensors with enhanced sensitivity and reliability.

Electrodeposition of Sn-doped hollow α-Fe2O3 nanostructures for photoelectrochemical water splitting

The hollow nanostructured hematite photoanodes were prepared by using template-assisted electrodeposition and heat-treatment process. The morphologies of the films were regulated through the synthesis parameters such as potential sweep rate, annealing temperature and Sn concentration in electrolyte, and confirmed by scanning electron microscopy and transmission electron microscopy. Sn-doping of hematite was achieved by using electrolyte containing tin salt. The photocurrent of Sn-doped hematite film reaches 0.25mA/cm2 in 1M NaOH at 1.23V vs. RHE by optimizing the synthesis parameters. It is noted that both Sn doping and hollow nanostructure can affect and improve the PEC performance of hematite film.

Ion diffusion and optical switching performance of 3D ordered nanostructured polyaniline films for advanced electrochemical/electrochromic devices

Nanostructured polyaniline (PANI) has the ability of fast and reversible acid/base doping/dedoping, multi-color changes and electron-donating/accepting using surface or near-surface reactions. Here we report PANI films with 3D ordered nanostructures through template-assisted electrodeposition method and aim to study the ion diffusion behavior as well as optical switching properties. It is found the ion diffusion coefficient is greatly increased because of the chain and crystalline structural modulation of deposited polyaniline arising from the template confinement effect. The ion diffusion reversibility and ion storage of 3D ordered macroporous (3DOM) PANI is highly improved due to the interconnected porous structure, which benefits for the fast penetration of ions. The optical switching properties of 3DOM PANI are also highly enhanced especially in the infrared region mainly because of the extended optical transmission path associated with the interconnected porous structure. The outstanding ion/electron doping/dedoping performance and better interaction with lights shown here render the ordered porous polyaniline a promising candidate as high-density electrochemical/electrochromic energy materials.

Electrochemical Synthesis and Characterization of Palladium Nanostructures

Palladium (Pd) is a good candidate material for hydrogen gas sensing at room temperature due to its high affinity to hydrogen. Pd in the form of nanostructures has demonstrated better performance in its gas sensing property as compared to that in the form of bulk metal because of its large surface area to volume ratio. In this work, various Pd nanostructures were synthesized via electrochemical route. Pd in the form of nanowires can be produced directly via template-assisted electrodeposition while Pd nanotubes were synthesized by galvanic displacement with morphology and composition governed by electrolyte temperature and reaction time. Using similar electrodeposition conditions, Pd in the form of nanoparticles were electrochemically decorated on the surfaces of ZnO rods and Si nanowires arrays. Growth study on various Pd nanostructures produced is presented here, using microscopy, diffraction and probe-based techniques for microstructural, morphological and chemical characterizations.

In search of an appropriate ionic liquid as electrolyte for macroporous manganese oxide film electrochemistry

Macroporous manganese oxide films were produced via template-assisted electrodeposition methodology employing polystyrene spheres with different diameters as template, thereby producing films with different pore sizes. The obtained films were true casts of the template(s) employed, as evidenced by Field Emission Scanning Electron Microscopy. The influence of pore size on capacitive behavior was assessed by cyclic voltammetry experiments in conventional propylene carbonate/LiClO4. Besides the influence of pore size, four different ionic liquids (ILs) were studied as electrolytes, showing that the physico–chemical nature of IL strongly affects the capacitive behavior of macroporous manganese oxide films, particularly in terms of stability throughout successive charge/discharge cycles. Optimal performance was obtained using 1-butyl-2,3-dimethylimidazolium bis(trifluoromethanesulfonyl)imide ([BMMI][Tf2N]), in which a constant increase in capacitance was observed for the first 700 charge/discharge cycles. This capacitance remained constant, at least until the 1,000 cycle, and was higher than the capacitance achieved using conventional organic solvents. Moreover, the electrochemical window obtained using [BMMI][Tf2N] was widened (from 0.9 V to 1.5 V), corresponding to a significant gain (up to 75%) in terms of energy density. Thus, the development of electrochemical capacitors may significantly benefit from macroporous manganese oxide film electrochemistry employing ionic liquids as electrolytes.

Controllable Template-Assisted Electrodeposition of Single- and Multi-Walled Nanotube Arrays for Electrochemical Energy Storage

Here we explored a novel ZnO nanorod array template-assisted electrodeposition route to synthesize large-scale single-walled polypyrrole (PPy) nanotube arrays (NTAs) and multi-walled MnO2/PPy/MnO2 NTAs. The structures of nanotubes, such as external and inner diameters, wall thicknesses, and lengths, can be well controlled by adjusting the diameters and lengths of ZnO nanorods and deposition time. The synthesized hybrid MnO2/PPy/MnO2 triple-walled nanotube arrays (TNTAs) as electrodes showed high supercapacitive perporties, excellent long-term cycling stability, and high energy and power densities. The PPy layers in MnO2/PPy/MnO2 TNTAs provide reliable electrical connections to MnO2 shells and uniquely serve as highly conductive cores to support the redox reactions in the active two-double MnO2 shells with highly electrolytic accessible surface area. The fabricated multi-walled NTAs allow high efficient utilization of electrode materials with facilitated transports of ions and electrons. The outstanding performance makes MnO2/PPy/MnO2 TNTAs promising candidates for supercapacitor electrodes.

Template-assisted electrodeposition of highly ordered macroporous zinc structures from an ionic liquid

The present paper shows the template-assisted electrodeposition of highly ordered macroporous zinc films in the ionic liquid 1-butyl-1-methylpyrrolidinium trifluoromethylsulfonate ([Py1,4]TfO). Polystyrene (PS) spheres were employed as templates, and zinc films were electrodeposited within the interstitial voids of the template. The results show that well-ordered two- or three-dimensional macroporous zinc films can easily be made. The obtained macroporous films showed diffractive light when illuminated with white light. The contact angle measurements revealed that the wettability of the employed ionic liquid on PS templates is much better than the one of aqueous solutions, leading to better infiltration into the interstitial voids of the PS spheres. Macroporous zinc is potentially interesting as host material for lithium ion batteries.