Electropolymerization of aniline in phosphonium-based ionic liquids and their application as protective films against corrosion

Conductive polyaniline (PANI) films were deposited on mild steel by an electropolymerization technique in the presence of different types of phosphonium-based ionic liquids, including tetrabutylphosphonium bromide, tetraoctylphosphonium bromide, and ethyltributylphosphonium diethylphosphate. The formation of the PANI films was followed by repetitive cyclic voltammetry scans and was confirmed with diffuse reflectance infrared Fourier transform spectroscopy. The morphology, surface roughness parameters, and grain sizes of these coatings were evaluated by atomic force microscopy. The corrosion behavior of the bare and PANI-coated electrodes was investigated by potentiodynamic polarization, open-circuit potential, and electrochemical impedance spectroscopy techniques in a simulated marine environment in 3.5 wt % aqueous NaCl solutions. The quantum chemical parameters of the PANI composite films were also calculated with parametric method 3, a semi-empirical quantum mechanical method. The theoretical conclusions were found to be consistent with the reported experimental data. (C) 2016 Wiley Periodicals, Inc

Electrochemistry and sensitive determination of a metal complex azo dye using graphite paste electrode modified with Na-bentonite

Graphite and its composites have gained considerable attention in electrochemical applications due to their excellent structural, electrical and chemical properties. In this study, a graphite paste electrode (GPE) modified with natural Na-bentonite (BGPE) is fabricated and utilized for the sensitive determination of Lanaset Red G (LRG) which is a kind of azo containing metal complex dye. The BGPE shows excellent enhancement in peak currents as compared to that of the GPE. The detection limit of LRG is determined to be as low as 0.65±0.08 when utilizing the BGPE as the working electrode in square wave voltammetry experiments (SWV). The electrochemical behavior of LRG is also investigated using a cyclic voltammetry (CV) technique to propose reaction mechanisms. Effects of pH and scan rate on the electrochemical behavior of LRG are studied to calculate transfer coefficients, the number of protons and electrons transferred in the redox reaction. The results show that a quasi-reversible reaction occurs on the BGPE surface/electrolyte interface. The morphology and the chemical characterization of both BGPE and GPE electrodes are investigated by the atomic force microscopy (AFM) technique and the diffuse reflectance infrared Fourier transform spectroscopy (DRIFT), respectively

Electrochemistry and sensitive determination of a metal complex azo dye using graphite paste electrode modified with Na-bentonite

Graphite and its composites have gained considerable attention in electrochemical applications due to their excellent structural, electrical and chemical properties. In this study, a graphite paste electrode (GPE) modified with natural Na-bentonite (BGPE) is fabricated and utilized for the sensitive determination of Lanaset Red G (LRG) which is a kind of azo containing metal complex dye. The BGPE shows excellent enhancement in peak currents as compared to that of the GPE. The detection limit of LRG is determined to be as low as 0.65±0.08 when utilizing the BGPE as the working electrode in square wave voltammetry experiments (SWV). The electrochemical behavior of LRG is also investigated using a cyclic voltammetry (CV) technique to propose reaction mechanisms. Effects of pH and scan rate on the electrochemical behavior of LRG are studied to calculate transfer coefficients, the number of protons and electrons transferred in the redox reaction. The results show that a quasi-reversible reaction occurs on the BGPE surface/electrolyte interface. The morphology and the chemical characterization of both BGPE and GPE electrodes are investigated by the atomic force microscopy (AFM) technique and the diffuse reflectance infrared Fourier transform spectroscopy (DRIFT), respectively

The electrochemical behavior of Co(TPTZ)(2) complex on different carbon based electrodes modified with TiO2 nanoparticles

Electrochemical behavior of cobalt (II) complex with the N-donor ligand 2,2'-bipyridyl-1,3,5-tripyridyl-s-triazine (TPTZ) was investigated to elucidate the electron-proton transfer mechanisms. The electrochemical response of the complex was studied using square-wave voltammetry (SWV) and electrochemical impedance spectroscopy (EIS) techniques. A conventional three-electrode system, consisting of glassy carbon (GCE), TiO2 modified glassy carbon (T/GCE), carbon paste (CPE) and TiO2 modified carbon paste (T/CPE) working electrodes were employed. The ligand/metal ratio and stability constant of the complex as well as the mechanisms of the electrode processes were elucidated by examining the effects of pH, ligand concentration and frequency on the voltammograms. The EIS results indicated that the samples modified with TiO2 had the higher charge transfer resistance than that of the bare electrodes and also suggested that the electroactivity of the electrode surfaces increased in the following order, T/CPE > CPE > T/GCE > GCE. The surface morphology of the working electrodes was also characterized by atomic force microscopy (AFM). The values of surface roughness parameters were found to be consistent with the results obtained by EIS experiments. (C) 2015 Elsevier B.V. All rights reserved