Template-free Electrodeposition Method Research Articles

Homogeneously distributed heterostructured interfaces in rice panicle-like SbBi-Bi2Se3-Sb2Se3 nanowalls for robust sodium storage

Antimony-based materials offer great potential for sodium-ion battery application owing to their high capacity and suitable Na alloying potential. However, their practical application is hampered by the rapid capacity decay resulting from serious volume change during cycling. Herein, we report a template-free electrodeposition method to grow SbBi-Bi2Se3-Sb2Se3 (SbBi-Se) self-supported nanowall array with a rice-panicle-like top surface directly on Cu substrates. During the electrodeposition, Bi, Sb, and Se have been simultaneously incorporated into the nanowalls, giving rise to an array structure with uniformly dispersed phases of SbBi alloy, and metal selenides Bi2Se3 and Sb2Se3. As a result, the heterostructured interfaces amongst these phases are also homogeneously distributed throughout the entire structure. The density functional theory calculation results indicate that these interfaces facilitate Na+ diffusion and promote electronic conduction, and the sample also demonstrates enhanced high-rate performance and superior cyclic retention with almost no capacity decay after 100 cycles at 0.7 A/g. More importantly, in-situ temperature sensing suggests that such a unique heterostructured material exhibits high thermal stability during charge/discharge, while ex-situ analysis confirms that this electrode material induces the formation of a highly stable SEI film, and verifies the high durability of these alloy and selenide phases allowing the interfaces to keep functioning during charge/discharge process.

Microflow-Enhanced Bubble Dynamics Along With Gradient Porous Surfaces

Abstract Boiling heat transfer has been a popular topic for decades because of its ability to remove a significant amount of thermal energy while maintaining a low wall superheat during the liquid phase change. Such boiling mechanisms can be tailored by engineering new boiling substrates through surface wettability modification and/or microscale feature installation. Here, we create new types of heterogeneous boiling surfaces that integrate vertical gradient micropores on macroscale fins by using a template-free electrodeposition method. The gradient morphology and corresponding gradient wettability simultaneously enable bubble nucleation on the top pores and capillary wicking through the bottom pores. With these unique wetting characteristics, we find that the gradient pores installed at the trench bottom demonstrate the most significant boiling enhancement in critical heat flux and heat transfer coefficients by 160% and 600%, respectively. This enhancement can be attributed to the microflow-enhanced nature of bubble departures around the fins while isolating bubble nucleation and liquid supply through gradient pores. These results provide fundamental insights into boiling mechanisms using porous media and the potential for future works that can optimize the design of multidimensional heterogeneous surfaces to engineer flow patterns and boiling mechanisms accordingly.

Enhanced photoelectrochemical water splitting with template-free electrodeposition of SnS nanorods photoelectrode

In this paper, SnS nanorods were first prepared in an acidic solution by adjusting the amounts of tri-sodium citrate at room temperature using template-free electro-deposition method. The morphological characteristics and photoelectrochemical (PEC) properties of SnS nanorods thin films were investigated. The phase purity properties of deposited SnS thin films were analyzed by X-ray diffraction (XRD), energy disperse spectroscopy (EDS) and Raman spectra measurements. The morphological characteristics of SnS nanorods were characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The band-gaps of SnS thin films were confirmed by UV–Vis–NIR diffuse reflectance spectrum. The PEC characterizations indicated that the photocurrent density of SnS nanorods thin films was about 46 μA/cm2 and the maximum IPCE value of SnS nanorods thin films was 9.3%. The fabrication of FTO/SnS (nanorods)/CdS/TiO2/Pt photoelectrode improved the PEC performances of SnS nanorods thin films greatly. The photocurrent density of FTO/SnS (nanorods)/CdS/TiO2/Pt reached 0.59 mA/cm2, and the maximum IPCE value of FTO/SnS (nanorods)/CdS/TiO2/Pt achieved 27.1%.

Electrodeposition of Platinum (Pt) Particles as a Catalyst of Hydrogenation of Acetone

Heterogeneous catalysts play an important role in accelerating chemical reactions in order to save energy and cost during the reaction process. Platinum (Pt) has received a great deal of attention for its application in many catalytic processes, but very few studies have evaluated it in the hydrogenation process of acetone. In this study, Pt particles were successfully grown on an indium tin oxide (ITO) coated glass substrate by means of a facile, one-step, and template-free electrodeposition method using a solution containing 2.0 mM H2PtCl6 and 0.5 M H2SO4 at room temperature. Potentiostatic and galvanostatic methods were employed to conduct the electrodeposition process under different potentials, current densities, and deposition times to observe their influence on the morphology of the electrodeposited Pt particles. It was found that the morphology of the particles could be facilely manipulated by adjusting the deposition current and potential by using the galvanostatic and potentiostatic methods, respectively. The potentiostatic method produced a spherical or bayberry-like shape whereas the galvanostatic method produced a flower-like shape. The sharp tips on the surface of the bayberry-like shape are electron-rich sites that can break the C = O bond in acetone, thereby forming C-OH bonds that can generate isopropanol molecules.

Template-free electrodeposition of SnS nanotubes and their photoelectrochemical properties

In this paper, SnS nanotubes are firstly prepared in acidic solution by template free electrodeposition method at room temperature. The morphological evolution and photoelectrochemical properties of SnS nanotubes are investigated. X-ray diffraction (XRD), energy dispersive X-ray spectrometry (EDS) and Raman spectra measurements examine the phase purities of deposited SnS thin films. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) characterizations indicate morphological properties of SnS nanotubes. The band-gap of SnS nanotubes is confirmed by UV–Vis-NIR diffuse reflection spectra. The photoelectrochemical measurements show that the photocurrent density of FTO/SnS nanotubes is about 31 μA/cm2 and maximum IPCE value of SnS nanotubes is 7.4%.

Template-free electro-synthesis of PbO2 nanorod with chrysanthemum-like array

PbO2 electrode is one of crucial materials in electrochemical field, however, the fabrications of nanostructured PbO2 materials are highly confined to the template method. In this work, the nanostructured PbO2 materials were controllably synthesized by template-free electrodeposition method. It is found that the microstructure of PbO2 material was highly depended on the electrochemical deposition models, i.e., cyclic voltammetry (CV) method, potentiostatic method (PM), pulse potentiostatic method (PPM) and pulse galvanostatic method (PGM). Especially, PbO2 nanorod built by nanoparticles with chrysanthemum-like array synthesized in the absence of template by pulse potential deposition method showed high specific capacitance and good stability for supercapacitor application.

Template-Free Electrochemical Preparation of Hexagonal CuSn Prism-Structural Electrode for Lithium-Ion Batteries

A hexagonal prism CuSn alloy was prepared at room temperature from 1-ethyl-3-methylimidazolium dicyanamide ([Emim][DCA]) by the direct template-free electrodeposition method with different concentrations of Cu(I) and Sn(II) at a low current density of 0.04 A dm−2. Moreover, the electrodeposition time was also investigated, and the results indicated that the composition of the CuSn alloy became complex and the structure turned unstable with expanding time. The cycling performance of the hexagonal prism-structural CuSn electrode was investigated, with the first discharge capacity of 345 mAh g−1 and a discharge capacity of about 210 mAh g−1 after 10 cycles.

Disordered photonics coupled with embedded nano-Au plasmonics inducing efficient photocurrent enhancement

Spatial order used to be considered as a benefit for photonics; but recently the study of disorder has broken into people’s horizons for its strong random scattering of light. In this work, disordered photonics coupled with plasmonics for efficiently enhanced photocurrent was first investigated using Au-ZnO nanowire array as a model. The embedded Au-ZnO nanowire array was facilely prepared using a template-free electrodeposition method. On the optimal plasmonic substrate, the photocurrent of disorder-enhanced Au-ZnO nanowire array is about 20-fold that of ZnO nanowire array. Both the plasmonic effect of Au NPs such as localized surface plasmons, surface plasmon polarizations and the disorder-enhanced photonics in the hybrid structure are available to improve the photoelectric conversion efficiency by enhancing the trapping of the simulated sunlight and the collection of charge carriers. Herein, disordered photonics was coupled with plasmonics to explain for the enhanced photocurrent. This work also provided a facile fabricating avenue for plasmonic noble metal embedded in semiconductor devices.

Embedded vertically aligned cadmium telluride nanorod arrays grown by one-step electrodeposition for enhanced energy conversion efficiency in three-dimensional nanostructured solar cells

Vertically aligned CdTe nanorods (NRs) arrays are successfully grown by a simple one-step and template-free electrodeposition method, and then embedded in the CdS window layer to form a novel three-dimensional (3D) heterostructure on flexible substrates. The parameters of electrodeposition such as deposition potential and pH of the solution are varied to analyze their important role in the formation of high quality CdTe NRs arrays. The photovoltaic conversion efficiency of the solar cell based on the 3D heterojunction structure is studied in detail. In comparison with the standard planar heterojunction solar cell, the 3D heterojunction solar cell exhibits better photovoltaic performance, which can be attributed to its enhanced optical absorption ability, increased heterojunction area and improved charge carrier transport. The better photoelectric property of the 3D heterojunction solar cell suggests great application potential in thin film solar cells, and the simple electrodeposition process represents a promising technique for large-scale fabrication of other nanostructured solar energy conversion devices.

A facile template-free electrodeposition method for vertically standing nanorods on conductive substrates and their applications for photoelectrochemical catalysis

A facile template-free electrodeposition technique is developed for large-scale fabrication of vertically standing silver nanorods (NRs) on transparent and conductive substrates. The diameter, length, and surface coverage of Ag NRs are dependent on the electrodeposition time and choice of substrates. The growth mechanism of vertically standing Ag NRs is investigated by tracking their morphology evolution as a function of deposition time. Because of their large specific surface area, oriented alignment, broad range light scattering, and light absorption tunability, these vertically standing NRs can be used as ideal substrates for thin layer photocatalysts for enhancing light absorption and charge collection. Preliminary tests on photoelectrochemical performance of bare Ag NRs, CdS modified Ag NRs, and Ag NRs converted to Ag2S NRs are presented. This simple NR fabrication method has been successfully applied to prepare Fe NRs as well. This technique can be extended to other conductive substrates and other materials for obtaining vertically standing NR structures.

Polyaniline nanocone arrays synthesized on three-dimensional graphene network by electrodeposition for supercapacitor electrodes

Highly ordered polyaniline nanocone arrays were synthesized on three-dimensional graphene network by template-free electrodeposition method. The morphology of the material was characterized by scanning electron microscopy. The structural features were analyzed by using Raman spectroscopy. Polyaniline nanocones align vertically on the surface of three-dimensional graphene network. Such morphology provides unblocked diffusion path for electrolyte ions, and increases the specific area of the material. The material possesses specific capacitance of 751.3Fg−1 in 1M HClO4 within the potential window of 0–0.7V, and has high rate capability as well as good cycling stability. At a current density of 10Ag−1, its capacitance is 88.5% of that at a current density of 1Ag−1. Furthermore, the material remains 93.2% of initial capacitance after 1000 cycles of charging–discharging test.

Template-free electrodeposition of highly oriented and aspect-ratio controlled ZnO hexagonal columnar arrays

We report an easy one-step template-free electrodeposition method for preparing large arrays of ZnO hexagonal nanocolumns, vertically oriented on a Au-coated Si substrate. Systematic scanning electron microscopy investigations revealed the potential of this method for obtaining a high degree of verticality and orientation of the nanostructures and for controlling their aspect-ratio in an easy manner. Further structural studies demonstrated that the as-obtained ZnO nanocolumns present a well defined hexagonal symmetry exhibiting an excellent crystallinity.

Template free electrochemical deposition of ZnSb nanotubes for Li ion battery anodes

ZnSb nanotubes were grown through a template free electrodeposition method under over-potential conditions. The growth of the nanotubes was attributed to the template effect from H(2) bubbles. Due to their hollow structure, the ZnSb nanotubes depicted better Li ion storage performance compared to that of ZnSb nanoparticles deposited under different conditions.

One-step electrodeposition of platinum nanoflowers and their high efficient catalytic activity for methanol electro-oxidation

A facile, one-step and template-free electrodeposition method has been developed for the first time to prepare porous Pt nanoflowers. The flowerlike architectures were confirmed by SEM, and further structurally characterized by XRD and electrochemical analyses. Compared to conventional nanosized Pt catalysts, as-prepared Pt nanoflowers exhibit remarkably higher catalytic activity and stronger poisoning-tolerance for the methanol electro-oxidation, and thus they are anticipated to find interesting applications in many important fields such as energy and catalysis.