Search results for "Aqueous electrolyte"
showing 9 items of 9 documents
Electroosmotic effects in the determination of ion mobilities of carrier-free radionuclides in free aqueous electrolyte solutions
2001
A device for on-line electromigration studies of radio-elements in free electrolytes has been tested by measuring the absolute individual ion mobilities of no-carrier-added single charged anions [99mTc]TcO4 - and [18F]F- and differently charged cations [137Cs]Cs+, [57Co]Co2+ and [241Am]Am3+ in inert aqueous electrolytes at 298.1 K. The observed ion mobilities were found to be influenced by electroosmosis in the migration tube. A relation to correct this effect is proposed. In addition, it was shown that the effect of electroosmosis may be suppressed by chemical treatment of the surface of the migration tube.
Aqueous electrolyte-gated ZnO transistors for environmental and biological sensing
2014
Electrolyte-gated transistors (EGTs) based on ZnO thin films, obtained by solution processing of suspensions of nanoparticles, have a low turn-on voltage (<0.5 V), a high on/off ratio and transconductance exceeding 0.2 mS. Importantly, the ZnO surface can be functionalized with a large variety of molecular recognition elements, making these devices ideal transducers in physiological and environmental monitoring. We present simple glucose-sensing and ion-selective EGTs, demonstrating the versatility of such devices in biosensing.
"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…
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…
Electrochemical dating of archaeological gold based on refined peak current determinations and Tafel analysis
2020
Abstract This report proposes a refined method to date archaeological gold samples based on the Tafel analysis of the ascending part of voltammetric curves corresponding to the oxidation of surface flakes of gold in contact with hydrochloric acid aqueous electrolyte. This allows estimating the equilibrium potential of gold oxidation correcting for irreversibility effects. This equilibrium potential can be correlated with the coverage of adsorbed oxygen species and hence the estimated age of the gold samples. A satisfactory potential/time calibration graph was constructed from a set of archaeological samples including two sets of samples from the Mapungubwe Gold Collection, South Africa (120…
Electrochemical ecology: VIMP monitoring of plant defense against external stressors
2015
The use of the voltammetry of immobilized particles (VIMP) approach, by means of the voltammetric response of microparticulate films from ethanolic leaf extracts in contact with aqueous electrolytes and direct contact probe leaf voltammetry, to monitor the defense of plants against external stressors is described. This approach is applied to study the chemical communication between plants of Peperomia obtusifolia A. Dietr. submitted to herbivory by the beetle Monoplatus sp.
Direct Measurement of Particle−Bubble Interactions in Aqueous Electrolyte: Dependence on Surfactant
1998
The aim of this study was to determine the influence of surfactant on the particle−bubble interaction. Therefore we constructed an experimental setup with which the interaction between colloidal pa...