IN-SITU SCANNING TUNNELING MICROSCOPIC STUDY OF NICKEL ELECTRODEPOSITION ON HOPG

The early stages of the electrodeposition of nickel on highly oriented pyrolytic graphite (HOPG) were investigated by in situ scanning tunnelling microscopy, scanning electron microscopy and electrochemical measurements. Experimental results showed that t

THE APPLICATION OF THE MPB4 THEORY TO THE INTERFACE BETWEEN 2 IMMISCIBLE ELECTROLYTE-SOLUTIONS .1. THE DIFFERENTIAL CAPACITANCE OF THE WATER NITROBENZENE INTERFACE

We use the MPB4 theory to calculate the differential capacitance of the interface between NaBr + water and tetrabutylammoniumtetraphenyl borate (TBATPB) + nitrobenzene at electrolyte concentrations of 0.01 M, 0.02 M and 0.05 M. In addition to the effects

PREDICTION OF THE GIBBS ENERGY OF ION TRANSFER ACROSS THE WATER NITROBENZENE INTERFACE USING 3 NEW TOPOLOGICAL INDEXES

Correlation analysis of the standard Gibbs energy for a series of tetraalkylammonium ions, protonated substituted ethylenediamine derivatives and protonated aromatic amine derivatives using three new topological indices Ax1, Ax2 and Ax has been studied. T

ELECTROCHEMICAL AND ELECTROCATALYTIC PROPERTIES OF IRON(III)-SUBSTITUTED DAWSON-TYPE TUNGSTOPHOSPHATE ANION

The electrochemical and electrocatalytic properties of iron(III)-substituted Dawson-type tungstophosphate anion are described. The anion exhibits a one-electron couple associated with the Fe(III) center and two two-electron waves attributed to redox proce

ELECTROCHEMICAL PREPARATION OF MICROELECTRODES MODIFIED WITH NONSTOICHIOMETRIC MIXED-VALENT MOLYBDENUM OXIDES

A blue, conductive, compact, mixed-valent Mo(VI, V) oxide film was grown on carbon fiber (CF) microelectrode surface by cycling the potential between +0.20 and -0.70 V vs. SCE in a fresh prepared Na2MoO4 solution (pH = 2, H2SO4). The thickness of the oxid

DIRECT ELECTROCHEMICAL REACTIONS OF CYTOCHROME-C AT IODIDE-MODIFIED ELECTRODES

Quasi-reversible and direct electron transfer was observed between an iodide-modified Au electrode and cytochrome c, as well as between cytochrome c in an iodide-containing solution and a bare Au electrode. The results suggest that an electrostatic intera

THEORETICAL-ANALYSIS OF NERNSTIAN PLOTS IN THE THIN-LAYER SPECTROPOTENTIOSTATIC TECHNIQUE

The Nernstian plots in a spectropotentiostatic experiment for complex electrode processes were studied theoretically. The plots are linear for an electron transfer process coupled with a preceding or succeeding chemical reaction, and the electron stoichio

INFLUENCE OF THE OHMIC POLARIZATION EFFECT ON THIN-LAYER SPECTROELECTROCHEMISTRY

The influence of thin-layer resistance in cyclic voltammetry was studied in detail. Under the experimental conditions, a linear relationship between the peak-peak potential difference and the product of the peak current and the resistance was obtained and

ELECTROCATALYTIC REDUCTION OF DIOXYGEN BY AN ELECTROCHEMICALLY POLYMERIZED FLAVIN ADENINE-DINUCLEOTIDE FILM

An electrochemically polymerized flavin adenine dinucleotide (FAD) film electrode is reported for the first time. The polymerized film was prepared by a two-step method. The electrocatalytic reduction of dioxygen at a glassy carbon electrode (GCE) modifie

ANODIC-OXIDATION OF HYDRAZINE ON GLASSY-CARBON ELECTRODES IN ACETONITRILE

The anodic oxidation kinetics of hydrazine on glassy carbon electrodes in acetonitrile were examined by cyclic voltammetry, a rotating ring-disc electrode technique and chronoamperometry. The experimental results of the rotating ring-disc electrode prove that hydrazine is oxidized to HN=NH, which cannot be oxidized further in acetonitrile. Hydrazine molecules are adsorbed on the electrode surface. One-third of the adsorbed hydrazine molecules are oxidized to HN=NH and the other two thirds act as proton acceptors. A possible mechanism of hydrazine oxidation is proposed.

AMPEROMETRIC DETECTION OF AMINO-ACIDS IN A FLOW-INJECTION SYSTEM WITH A NICKEL(II)-MODIFIED ELECTRODE WITH AN EASTMAN-AQ POLYMER FILM

Amperometic flow measurements were made at +0.55 V (vs. Ag/AgCl) in 0.1 mol l-1 KOH electrolyte with an Ni(II) chemically modified electrode (CME) with an Eastman-AQ polymer film. The use and characteristics of a Ni(II)-containing crystalline and polymer-modified electrode obtained by a double coating step as a detector for amino acids in a flow-injection system using reversed-phase liquid chromatography are described. The detection of these analytes is based on the higher oxidation state of nickel (NiOOH) controlled by the applied potential. The electroanalytical parameters and the detection current for a series of amines and amino acids were investigated. The use of such a CME in the flow-injection technique was found to be suitable in a solution at low pH. The linear range for glycine is 5 X 10(-6)-0.1 mol 1-1 with a detection limit of 1.0 X 10(-6) mol l-1. A 1 X 10(-4) mol 1-1 mixture of serine and tyrosine was also detected after separation on an Nucleosil C18 column.

STUDY OF A 1/12 PHOSPHOMOLYBDIC ANION DOPED POLYPYRROLE FILM ELECTRODE AND ITS CATALYSIS

A phosphomolybdic anion doped polypyrrole (PMo12O403- + PPy) film electrode has been prepared by electrochemical polymerization of pyrrole in an aqueous solution of 0.5 mol l-1 H2SO4 or 0.5 mol l-1 KNO3 containing PMo12O403- anions, and characterized by scanning electron microscopy and in-situ UV-visible spectroelectrochemical methods. The film electrode obtained is very stable upon potential cycling in acidic solution, but not in neutral solution. The catalytic effect of the film electrode on the reduction of ClO3- and BrO3- was studied.