A Highly Sensitive Electrochemical Impedance Spectroscopy Immunosensor for Determination of 1-Pyrenebutyric Acid Based on the Bifunctionality of Nafion/Gold Nanoparticles Composite Electrode

From a technological point of view, measurement of the corrosion rate of magnesium (Mg) and its alloys is critical for lifetime predictions of Mg-based structures and for comparative assessments of their corrosion protection ability. Whilst weight loss, hydrogen evolution, and polarization curves methods are frequently used for measuring the corrosion rate, the determination of values by electrochemical impedance spectroscopy (EIS) is relatively scarce and has only been realized recently. This technique seems to be the most suitable for monitoring corrosion rate values due to its “non-destructive” character, its reproducibility, and its reliable determination of small corrosion rates, much lower than those measured by other techniques. This review aims to picture the state-of-the-art technique of using EIS for measuring the corrosion rate of Mg. This paper starts by introducing some fundamental aspects of the most widely used methods for monitoring the corrosion rate of Mg/Mg alloy and continues by briefly explaining some of the fundamental concepts surrounding EIS, which are essential for the user to be able to understand how to interpret the EIS spectra. Lastly, these concepts are applied, and different approaches that have been proposed to obtain quantitative values of corrosion rate since the 1990s are discussed.

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The influence of gold nanoparticles on the electroactivity of nickel tetrasulfonated phthalocyanine

Journal of Porphyrins and Phthalocyanines ◽

10.1142/s1088424614500333 ◽

2014 ◽

Vol 18 (08n09) ◽

pp. 642-651 ◽

Cited By ~ 7

Author(s):

Audacity Maringa ◽

Tebello Nyokong

Keyword(s):

Gold Nanoparticles ◽

Electrochemical Impedance Spectroscopy ◽

Impedance Spectroscopy ◽

Glassy Carbon ◽

Electrochemical Impedance ◽

Modified Electrodes ◽

Enhancement Effect ◽

Carbon Electrode ◽

Cathodic Peak ◽

Peak Separation

We report on the electrodeposition of gold nanoparticles ( AuNPs ) on a glassy carbon electrode (GCE) followed by deposition of nickel tetrasulfonated phthalocyanine ( NiTSPc ) film by electropolymerization (poly- NiTSPc -GCE) to form Poly- NiTSPc / AuNPs -GCE. The presence of the gold nanoparticles caused a lowering of the anodic and cathodic peak separation (ΔE p ) of ferricyanide from 126 mV on poly- NiTSPc to 110 mV on poly- NiTSPc / AuNPs . The electrooxidation of nitrite improved on modified electrodes compared to GCE, with the latter giving E p = 0.78 V and the modified electrodes gave E p = 0.62 V or 0.61 V. Poly- NiTSPc / AuNPs -GCE had higher currents compared to poly- NiTSPc -GCE. This indicates the enhancement effect caused by the AuNPs . Electrochemical impedance spectroscopy and chronoamperometric studies also showed that poly- NiTSPc / AuNPs -GCE was a better electrocatalyst than poly- NiTSPc -GCE or AuNPs -GCE.

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