Search results for " electrode"
showing 10 items of 301 documents
Electrochemical characterization of natural gold samples using the voltammetry of immobilized particles
2017
The application of the voltammetry of immobilized particles for characterizing natural gold samples from different geological settings and dating vein deposits is described. This is based on recording characteristic electrochemical oxidation signatures of gold and silver following the attachment of metal sub-microsamples to graphite electrodes. Keywords: Electrochemistry, Gold, Mineralogy, Placer deposits, Vein deposits, Nuggets
Electrochemical discrimination of manufacturing types of pottery from Magna Mater Temple and Fora of Nerva and Caesar (Rome, Italy)
2018
Abstract The voltammetry of immobilized microparticles (VIMP) methodology is applied to a series of pottery samples from the Roman sites of Nerva's Forum (second half of 9th-early 11th A.D), Caesar's Forum (second half of 9th-early 11th A.D) and Magna Mater Temple (III century). The VIMP sampling applied to voltammetric and electrochemical impedance spectroscopy (EIS) measurements was applied by the first time to acquire archaeometric information on archaeological pottery. VIMP measurements using pressed sample pellets on gold electrodes in contact with air-saturated 0.10 M H2SO4 have permitted to detect voltammetric signals for the reduction/oxidation of Fe and Mn minerals as well as catal…
Novel tree-like WO3 nanoplatelets with very high surface area synthesized by anodization under controlled hydrodynamic conditions
2016
In the present work, a new WO3 nanostructure has been obtained by anodization in a H2SO4/NaF electrolyte under controlled hydrodynamic conditions using a Rotating Disk Electrode (RDE) configuration. Anodized samples were analyzed by means of Field Emission Scanning Electronic Microscopy (FESEM), Confocal Raman Microscopy and photoelectrochemical measurements. The new nanostructure, which consists of nanoplatelets clusters growing in a tree-like manner, presents a very high surface area exposed to the electrolyte, leading to an outstanding enhancement of its photoelectrochemical activity. Obtained results show that the size of nanostructures and the percentage of electrode surface covered by…
Parametrical study of multilayer structures for CIGS solar cells
2014
In this paper, a numerical analysis of relevant electrical parameters of multilayer structures for CIGS-based solar cells was carried out, employing the simulation software wxAMPS. In particular, we have focused on thin film cells having a ZnO:Al/ZnO/CdS/CIGS structure with a Molybdenum back contact. The aim of this work is to establish good theoretical reference values for an ongoing experimental activity, where our technology of choice is the single-step electrodeposition. In detail, we have analyzed how the main electrical properties change with the bang gap and the thickness of the absorber layer, for such a type of solar cell structure. Our results show that both efficiency and fill fa…
Influence of sulphite on the passivation of iron
1991
Abstract Mossbauer spectroscopy and electrochemical measurements were used to study the passivation of iron and steels in a sulphite containing solution. The potentiodynamic curves show that passivation occurs at −140 mV potential vs saturated calomel electrode ( sce ). The main phase of the passive layer was found to be γ-FeOOH, while FeSO 4 ·H 2 O on the surface and FeSO 3 ·3H 2 O inside the layer were identified as minor phases in the case of polarization in a solution of pH 3.37. Only γ-FeOOH was observed on the surface of samples polarized at pH 6.6.
An experimental analysis of thick-film solid-state reference electrodes
2012
Thick-Film planar solid-state Silver/Silver Chloride (Ag/AgCl) reference electrodes were developed and tested for ion susceptibility and long term drift in approximately 0.04 M potassium chloride (KCl) solution. Various types of electrodes were tested exhibiting stabilities down to 2 millivolts per decade change of chloride concentration. It is demonstrated that Thick-Film reference electrodes are suitable for use in underground soil measurements due to their ruggedness and robustness.
Double Step Electrochemical Process for the Deposition of Superhydrophobic Coatings for Enhanced Corrosion Resistance
2021
Superhydrophobic surface on anodized AA5083 sample was obtained by an electrochemical process. Scanning Electron Microscopy and Fourier Transform Infrared Spectroscopy analyses revealed the hierarchical structure of the coating and the presence of manganese stearate. These features were crucial for the coating superhydrophobicity, demonstrated by a measured contact angle of ~ 163° and its self-cleaning ability. Electrochemical characterization in an aqueous solution mimicking seawater proved an enhanced corrosion resistance due to the superhydrophobic coating with respect to anodized AA5083 sample that also lasted after 20 immersion days in Cl- containing electrolyte.
Electrodeposition of supported gadolinium-doped ceria solid solution nanowires
2012
Gadolinium-ceria solid solution nanowires with tunable composition have been prepared through template cathodic electrodeposition from solutions containing Ce 3+Gd 3+ in a variable ratio. The employed template is Porous Anodic Alumina because it can function as thermal resistant separator supporting the nanowires if used as ionic conductor in Solid Oxide Fuel Cell (SOFC). Scanning Electron Microscopy of the deposited nanostructures revealed that the use of ethanol as solvent and metal chloride as electrolyte allowed to prepare continuous, compact and well defined nanowires with morphological features stable even after thermal treatment. EDX compositional analysis confirms the presence of bo…
Room temperature electrodeposition of photoactive Cd(OH)2 nanowires
2009
Cd(OH)2 nanowires (NWs) were successfully prepared by room temperature electrogeneration of base using Cd(NO3)2 aqueous electrolyte and Anodic Alumina Membrane (AAM) as template. Cd(OH)2 films have been also deposited on tin-doped indium oxide (ITO) for comparison. SEM analysis shows high quality deposits made of closely packed nanowires (NWs) into AAM and uniform flake-like surface on ITO. XRD analysis reveals that Cd(OH)2 films on ITO are polycrystalline, while the nanowires grow along the preferential directions [100] and [110]. Photoelectrochemical measurements show that Cd(OH)2 NWs are photoactive materials with indirect and direct band gap of 2.15 and 2.75 eV, respectively. Keywords: …
Solid-state electrochemical characterization of emissions and authorities producing Roman brass coins
2020
[EN] The voltammetry of immobilized particles (VIMP) is applied to describe the solid state electrochemistry of brass. This methodology, which involves sampling at the nanogram level, is applied to discriminate mints/authorities producing different Roman monetary emissions covering since the Republic (88 BCE) to Domitianus (55-96 CE) Upon attachment to graphite electrodes in contact with aqueous acetate buffer at pH 4.75, well defined voltarnmetric responses were obtained centered on Cu- and Zn-localized signals whose intensity can be correlated to EMP data, being sensitive to the contents of Zn (15-30 wt.%) and Sn (0.01-1.1 wt.%). Voltammetric data, combined with ATR-FTIR and FIB-PESEM/EDS…