Search results for " ELECTRODEPOSITION"
showing 10 items of 65 documents
Formation of lead by reduction of electrodeposited PbO2: comparison between bulk films and nanowires fabrication
2012
Metallic lead was deposited, both in form of bulk films and nanowire array within pores of anodic alumina membranes, following a new two-step procedure, consisting in anodic electrodeposition of α-PbO2, followed by its reduction to metallic lead. This method allows to overcome drawbacks of the “direct” electrodeposition of lead from aqueous solution, consisting, essentially, in the formation of dendritic deposits. Here, we report the comparison between results obtained in the two cases and discuss the kinetic of oxide reduction both for films and nanowires. Deposit morphology and structure are also discussed. We have found that reduction of α-PbO2 films proceeds always at high speed and uni…
Fabrication and Photoelectrochemical Behavior of Ordered CIGS Nanowire Arrays for Application in Solar Cells
2010
In this work, we report some preliminary results concerning the fabrication of quaternary copper, indium, gallium, and selenium CIGS nanowires that were grown inside the channels of an anodic alumina membrane by one-step potentiostatic deposition at different applied potentials and room temperature. A tunable nanowire composition was achieved through a manipulation of the applied potential and electrolyte composition. X-ray diffraction analysis showed that nanowires, whose chemical composition was determined by energy-dispersive spectroscopy analysis, were amorphous. A composition of Cu0.203In0.153Ga0.131Se0.513, very close to the stoichiometric value, was obtained. These nanostructures wer…
Electrodeposition of CeO2 and Co-Doped CeO2 Nanotubes by Cyclic Anodization in Porous Alumina Membranes
2013
An anodic electrodeposition process is proposed to prepare CeO2 and Co-doped CeO2 nanotubes. Anodic alumina membrane is used as template and linear sweep voltammetry is employed to allow the formation of nanotubes without alumina dissolution. SEM micrographs showed large arrays of well defined and aligned NTs, which resulted to be crystalline soon after deposition according to XRD diffraction patterns and Raman Spectroscopy.
Synthesis of Silver Gallium Selenide (AgGaSe2) Nanotubes and Nanowires by Template-Based Electrodeposition
2020
In this work, a systematic investigation of the different parameters that control the electrodeposition processes was carried out at the aim to synthetizing AgGaSe₂ nanostructures. We found that pH is a key parameter to control both the morphology and composition of the nanostructures. Low pH favours mainly the formation of Ag2Se nanotubes with a scarce mechanical stability, while multi-phase nanowires well anchored to the substrate were obtained at higher pH. We also found that it was necessary to increase dramatically the concentration of the gallium precursor into the deposition bath in order to obtain AgGaSe₂ owing to lower redox potential of the Ga3+/Ga couple than Ag2+/Ag and Se4+/Se.…
ZnO Nanoestructured Layers Processing with Morphology Control by Pulsed Electrodeposition
2011
The fabrication of nanostructured ZnO thin films is a critic process for a lot of applications of this semiconductor material. The final properties of this film depend fundamentally of the morphology of the sintered layer. In this paper a process is presented for the fabrication of ZnO nanostructured layers with morphology control by pulsed electrodeposition over ITO. Process optimization is achieved by pulsed electrodeposition and results are assessed after a careful characterization of both morphology and electrical properties. SEM is used for nucleation analysis on pulsed deposited samples. Optical properties like transmission spectra and Indirect Optical Band Gap are used to evaluate th…
Electrochemical Deposition Mechanism for ZnO Nanorods: Diffusion Coefficient and Growth Models
2011
Fabrication of nanostructured ZnO thin films is a critical process for many applications based on semiconductor devices. So on understanding of the electrochemical deposition mechanism is also fundamental for knowing the optimal conditions on growth of ZnO nanorods by electrodeposition. In this paper the electrochemical mechanism for ZnO nanorods formation is studied. Results are based on the evolution of the diffusion coefficient using the Cotrell equation, and different growth models proposed by Scharifcker and Hills for nucleation and growth.
Lead Nanowires for Microaccumulators Obtained Through Indirect Electrochemical Template Deposition
2010
Metallic lead nanowires were deposited within pores of commercial anodic alumina membranes having an average pore diameter of 210 nm. "Direct" electrodeposition was attempted from 0.1 M Pb(NO 3 ) 2 aqueous solution with a variable concentration of H 3 BO 3 as a chelating agent, but it gave unsatisfactory results. An "indirect" two-step deposition procedure was then adopted, consisting of the anodic electrodeposition of α-PbO 2 nanowires, followed by their in situ reduction to metallic lead. Both these processes occurred at a high rate so that the indirect method led to a complete template pore filling with pure polycrystalline Pb in short times and with a high current efficiency.
Template electrosynthesis of La(OH)3 and Nd(OH)3 nanowires using porous anodic alumina membranes
2007
High quality arrays of Ln(OH)3 (Ln = La, Nd) nanowires have been successfully fabricated for the first time by an electrochemical process using anodic alumina membrane templates. A physico-chemical characterisation of electrodeposited hydroxides has been carried out by different techniques (XRD, SEM and EDX). The results show that the synthesized nanostructures are crystalline, dense, continuous, well aligned, and with high aspect ratio, suggesting further development of possible applications in the lanthanide family species. Keywords: Nanowires, Anodic alumina membranes, Hydroxide electrodeposition, Template, Lanthanide compounds
Nanostructured lead-acid negative electrode with reduced graphene oxide
2021
Aim of this work is to develop a new nano-structured and nano-composite lead acid negative electrode with reduced graphene oxide (rGO). Nanostructured electrodes are fabricated by template electrodeposition of lead nanowires on a lead current collector. A polycarbonate track-etched membrane was used as a template (200 nm mean pores diameter). rGO was deposited on the nanostructured electrode from a graphene oxide (GO) dispersion in acetate buffer solution (ABS) (0.2 g/L). Potentiostatic deposition of rGO at -0.8 V vs. standard calomel electrode (SCE) was performed. Electrode with rGO was tested as negative electrode in cell with 5M sulfuric acid solution, a commercial pasted positive plate,…
One-step electrodeposition of superhydrophobic coating on 316L stainless steel
2021
Superhydrophobic coatings were fabricated through a one-step electrochemical process onto the surface of 316L stainless steel samples. The presence of hierarchical structures at micro/nanoscale and manganese stearate into the coatings gave superhydrophobicity to the coating, with contact angle of ~160°, and self-cleaning ability. Corrosion resistance of 316L samples was also assessed also after the electrodeposition process through Electrochemical Impedance Spectra recorded in an aqueous solution mimicking seawater condition.