Search results for " ELECTROLYTE"

"One-touch" voltammetry of microparticles for the identification of corrosion products in archaeological lead

2011

Voltammetry of microparticles is applied to the identification of lead corrosion products by means of an essentially non-invasive 'one-touch' technique based on the use of graphite pencil. This methodology permits the mechanical attachment of few nanograms of sample from the surface of lead archaeological artefacts to a paraffin-impregnated graphite electrode, which, upon immersion in aqueous electrolytes, provides distinctive voltammetric responses for litharge and cotunnite- anglesite-, cerusite-based corrosion products. The reported method is applied to the identification of corrosion products in archaeological lead pieces from different Iberian sites in Valencia (Spain). © 2011 WILEY-VC…

Influence of the chemical dissolution of MnS inclusions on the composition of passive films and the local electrochemical behaviour of stainless stee…

2006

Abstract Immersion of stainless steel containing MnS inclusions in aqueous electrolytes leads to the chemical dissolution of these heterogeneities. Chemical dissolution of MnS inclusions in 1M NaCl, pH=3 was studied using in-situ AFM and the dissolution rate of MnS was estimated between 0.04 and 0.19 μm 3 /min. The local electrochemical measurements reveal that the chemical dissolution of MnS inclusions promotes pitting corrosion. Similary, chemical dissolution of MnS inclusions in IM NaClO 4 , pH=3 solution modified the surface close to the inclusions by the presence of FeSO 4 in the passive film.

Stabilizing organic photocathodes by low-temperature atomic layer deposition of TiO2

2017

Organic semiconductor light absorbers are receiving attention for their potential application in photoelectrochemical (PEC) cells for renewable fuels generation. Key to their advancement is precise control of the interfaces between charge-selective contacts, absorber layers, and electrocatalysts, while maintaining compatibility with an aqueous electrolyte environment. Here we demonstrate a new process for low-temperature atomic layer deposition (ALD) of TiO2 onto a P3HT:PCBM polymer blend surface for stable high-performance organic PEC photocathodes. This ALD TiO2 layer provides three key functions: (1) formation of an electron-selective contact to the polymer to enable photovoltage and pho…

pH and supporting electrolyte concentration effects on the passive transport of cationic and anionic drugs through fixed charge membranes

1999

Abstract The effects of pH and supporting electrolyte concentration on the passive transport of an ionized (cationic or anionic) drug through a thick fixed charge membrane have been theoretically studied. This system constitutes a simplified model for the pH controlled ion transport and drug delivery through membranes of biological and pharmaceutical interest. Calculations were carried out for different values of the membrane fixed charge, supporting electrolyte and drug concentrations covering a broad range of the conditions usually found in experiments. The theoretical approach employed is based on the Nernst–Planck flux equations, and all of the species present in the system (the neutral…

Access to Phylogeny from Voltammetric Fingerprints of Seeds: the Apsparagus Case

2016

A methodology for characterizing vegetal taxonomic groups from the voltammetric fingerprints of polyphenolic components of seeds is described. It is based on recording the voltammetric response of microparticulate films deposited on glassy carbon electrodes from seed extracts using different organic solvents. The obtained responses in contact with aqueous electrolytes provided characteristic voltammetric profiles at the level of genera/subgenera and/or families using bivariant and multivariant chemometric methods. The voltammograms of 14 species from 5 different families provided family-characteristic patterns. Analysis of voltammetric responses for a set of 20 species of the Asparagus genu…

Ionic conduction, rectification, and selectivity in single conical nanopores

2006

Modern track-etching methods allow the preparation of membranes containing a single charged conical nanopore that shows high ionic permselectivity due to the electrical interactions of the surface pore charges with the mobile ions in the aqueous solution. The nanopore has potential applications in electrically assisted single-particle detection, analysis, and separation of biomolecules. We present a detailed theoretical and experimental account of the effects of pore radii and electrolyte concentration on the current-voltage and current-concentration curves. The physical model used is based on the Nernst-Planck and Poisson equations. Since the validity of continuum models for the descriptio…

Ion transport and selectivity in nanopores with spatially inhomogeneous fixed charge distributions

2007

Polymeric nanopores with fixed charges show ionic selectivity when immersed in aqueous electrolyte solutions. The understanding of the electrical interaction between these charges and the mobile ions confined in the inside nanopore solution is the key issue in the design of potential applications. The authors have theoretically described the effects that spatially inhomogeneous fixed charge distributions exert on the ionic transport and selectivity properties of the nanopore. A comprehensive set of one-dimensional distributions including the skin, core, cluster, and asymmetric cases are analyzed on the basis of the Nernst-Planck equations. Current-voltage curves, nanopore potentials, and tr…

Mott-Schottky analysis of differential capacitance data of passive-film electrolyte junctions. Is it really providing correct physical insights on th…

2009

Electrochemically Controlled Ion Dynamics in Porphyrin Nanostructures

2020

peer-reviewed The full text of this article will not be available in ULIR until the embargo expires on the 22/07/2021 The dynamics of ion intercalation into solid matrices influences the performance of key components in most energy storage devices (Li-ion batteries, supercapacitors, fuel cells, etc.). Electrochemical methods provide key information on the thermodynamics and kinetics of these ion-transfer processes but are restricted to matrices supported on electronically conductive substrates. In this article, the electrified liquid|liquid interface is introduced as an ideal platform to probe the thermodynamics and kinetics of reversible ion intercalation with nonelectronically active matr…

CuZnSnSe NANOTUBES AND NANOWIRES BY TEMPLATE ELECTROSYNTHESIS

2014

In this work we present some results of an extensive investigation aimed to find suitable conditions to grow CuZnSnSe (CZTSe) nanostructures through single-step electrodeposition into the channels of polycarbonate membranes. After the optimization of several electrodeposition parameters, we have found that pulsed current deposition, between 0 and -1 mA cm-2, is the best way to obtain CZTSe nanostructures mechanically attached to the support. An interesting result concerns the effect of supporting electrolyte in the deposition bath. In fact, changing its concentration it is possible to vary morphology of nanostructures from nanotubes to nanowires. In both case uniform arrays of ordered nanos…