Search results for "anodizing"
showing 10 items of 116 documents
Effect of plastic deformation on the anodic electroluminescence accompanying the early stage of electrolytic oxidation of cadmium
1995
A simple method to fabricate high-performance nanostructured WO3 photocatalysts with adjusted morphology in the presence of complexing agents
2017
[EN] The rich and complex chemistry of tungsten was employed to synthesize innovative WO3 nanoplatelets/nanosheets by simple anodization in acidic electrolytes containing different concentrations of complexing agents or ligands, namely F- and H2O2. The morphological and photoelectrochemical properties of these nanostructures were characterized. The best of these nanostructures generated stable photocurrent densities of ca. 1.8 mA cm(-2) at relatively low bias potentials (for WO3) of 0.7 V-Ag/AgCl under simulated solar irradiation, which can be attributed to a very high active surface area. This work demonstrates that the morphology and dimensions of these nanostructures, as well as their ph…
Three dimensional PEDOT nanowires network
2016
Abstract A three dimensional (3D) structure of poly(3,4-ethylenedioxythiophene) (PEDOT) nanowires have been prepared by electrochemical polymerization using 3D-alumina templates. The templates were synthesized by pulse anodization in an electrochemical bath. A 3D free standing network has been obtained after the template removal. The morphological analysis by electron microscopy shows the existence of a 3D PEDOT nanowires network whose nanowire diameter is around 20 nm for the vertical nanowires and 10 nm for the transversal connections. Electrical properties such as the I–V characteristics and the Seebeck coefficient were studied for the nanowires network. Also, the optical properties have…
INFLUENCE OF THE ANODIZATION CONDITIONS ON THE ELECTRONIC PROPERTIES AND CRYSTALLOGRAPHIC STRUCTURES OF THE CORROSION LAYERS ON TUNGSTEN. A PHOTOELEC…
1983
ABSTRACT The influence of morphology, composition and crystallographic structure on the photoelectrochemical behaviour of anodic oxide films on tungsten obtained in various conditions of anodization has been investigated. Different photocurrent spectra and absorption edges were obtained for each type of film. Optical band gaps ranging between 2.55 eV and 3.15 eV were determined for crystalline and amorphous WO 3 films grown in different conditions. The low quantum efficiency of the anodic films must be attributed to the presence of an amorphous (a-W0 3 ) film which controls the transport of the injected photocarriers.
Study of the annealing conditions and photoelectrochemical characterization of a new iron oxide bi-layered nanostructure for water splitting
2016
Iron oxide nanostructures have emerged as promising materials for being used as photocatalysts for hydrogen production due to their advantageous properties. However, their low carrier mobility and short hole diffusion length limit their efficiency in water splitting. To overcome these drawbacks, in the present study, we synthetized a new hematite (alpha-Fe2O3) bi-layered nanostructure consisting of a top nanosphere layer and a nanotubular underneath one by electrochemical anodization. Annealing parameters such as temperature, heating rate and atmosphere were studied in detail in order to determine the optimum annealing conditions for the synthetized nanostructure. The obtained new bi-layere…
Synergistic Use of Electrochemical Impedance Spectroscopy and Photoelectrochemical Measurements for Studying Solid State Properties of Anodic HfO2
2017
Within the past years, intense research has been carried out on HfO2 as high k material, promising candidate to replace SiO2 as gate dielectric in CMOS based devices (1), and as metal oxide for resistive random access memory (ReRAM) (2). For both technological applications compact, uniform and flat oxides are necessary, and a detailed understanding of their physical properties as a function of the fabrication conditions is strongly. Hafnia performance can be significantly influenced by carrier trapping taking place at pre-existing precursors states (induced by oxygen vacancies, interstitial ions, impurities acting as dopants), or by self-trapping in a perfect lattice, where the potential we…
Visible-light photoelectrodegradation of diuron on WO3 nanostructures
2018
[EN] The degradation of pesticide diuron has been explored by photoelectrocatalysis (PEC) under visible light illumination using two different WO3 nanostructures, obtained by anodization of tungsten. The highest degradation efficiency (73%) was obtained for WO3 nanosheets synthesized in the presence of small amounts of hydrogen peroxide (0.05 M). For that nanostructure, the kinetic coefficient for diuron degradation was 133% higher than that for the other nanostructure (anodized in the presence of fluoride anions). These results have been explained by taking into account the different architecture and dimensions of the two WO3 nanostructures under study.
Template-Based Fabrication of Nanometer-Scaled Actuators from Liquid-Crystalline Elastomers
2010
Anodic Alumina Membranes: From Electrochemical Growth to Use as Template for Fabrication of Nanostructured Electrodes
2022
The great success of anodic alumina membranes is due to their morphological features coupled to both thermal and chemical stability. The electrochemical fabrication allows accurate control of the porous structure: in fact, the membrane morphological characteristics (pore length, pore diameter and cell density) can be controlled by adjusting the anodizing parameters (bath, temperature, voltage and time). This article deals with both the fabrication and use of anodic alumina membranes. In particular, we will show the specific role of the addition of aluminum ions to phosphoric acid-based anodizing solution in modifying the morphology of anodic alumina membranes. Anodic alumina membranes were …
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.