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

2014 ◽  
Vol 18 (08n09) ◽  
pp. 642-651 ◽  
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.

scholarly journals Investigation of Electrochemical Behaviour of Quercetin on the Modified Electrode Surfaces with Procaine and Aminophenyl in Non-Aquous Medium

2008 ◽  
Vol 5 (3) ◽  
pp. 539-550 ◽  
Author(s):  
Ibrahim Ender Mulazimoglu ◽  
Erdal Ozkan
Keyword(s):  
Cyclic Voltammetry ◽  
Electrochemical Impedance Spectroscopy ◽  
Impedance Spectroscopy ◽  
Glassy Carbon ◽  
Electrode Surface ◽  
Electrochemical Impedance ◽  
Electrochemical Behaviour ◽  
Carbon Electrode ◽  
Amine Group ◽  
Tetrabutylammonium Tetrafluoroborate

In this study, cyclic voltammetry and electrochemical ımpedance spectroscopy have been used to investigate the electrochemical behaviour of quercetin (3,3′,4′,5,7-pentahydroxyflavone) on the procaine and aminophenyl modified electrode. The modification of procaine and aminophenyl binded electrode surface with quercetin was performed in +0,3/+2,8 V (for procaine) and +0,4/+1,5 V (for aminophenyl) potential range using 100 mV s-1scanning rate having 10 cycle. A solution of 0.1 M tetrabutylammonium tetrafluoroborate in acetonitrile was used as a non-aquous solvent. For the modification process a solution of 1 mM quercetin in 0.1 M tetrabutylammonium tetrafluoroborate was used. In order to obtain these two surface, a solution of 1 mM procaine and 1 mM nitrophenyl diazonium salt in 0.1 M tetrabutylammonium tetrafluoroborate was used. By using these solutions bare glassy carbon electrode surface was modified. Nitrophenyl was reduced to amine group in 0.1 M HCl medium on the nitrophenyl modified glassy carbon elelctrode surface. Procaine modified glassy carbon electrode surface was quite electroactive. Although nitrophenyl modified glassy carbon elelctrode surface was electroinactive, it was activated by reducing nitro group into amine group. For the characterization of the modified surface 1 mM ferrocene in 0.1 M tetrabutylammonium tetrafluoroborate for cyclic voltammetry and 1 mM ferricyanide/ferrocyanide (1:1) mixture in 0,1 M KCl for electrochemical impedance spectroscopy were used.

scholarly journals pH Controlled Impedimetric Sensing of Copper(II) Ion Using Oxytocin as Recognition Element

Surfaces ◽  
2018 ◽  
Vol 1 (1) ◽  
pp. 90-95 ◽  
Author(s):  
Kiran Tadi ◽  
Israel Alshanski ◽  
Mattan Hurevich ◽  
Shlomo Yitzchaik
Keyword(s):  
Electrochemical Impedance Spectroscopy ◽  
Impedance Spectroscopy ◽  
Surface Chemistry ◽  
Glassy Carbon ◽  
Electrochemical Impedance ◽  
Carbon Electrode ◽  
Recognition Element ◽  
High Affinity ◽  
Specific Metal ◽  
Selective Sensor

We report the modulation of the specific metal gation properties of a peptide and demonstrate a highly selective sensor for copper(II) ion. The neuropeptide oxytocin (OT) is reported for its high affinity towards Zn2+ and Cu2+ at physiological pH. The binding of the metal ions to OT is tuned by altering the pH of the medium. OT was self-assembled on glassy carbon electrode using surface chemistry, and electrochemical impedance spectroscopy (EIS) was used to probe the binding of Cu2+. Our results clearly indicate that at pH 10.0, the binding of Cu2+ to OT is increased compared to that at pH 7.0, while the binding to Zn2+ becomes almost negligible. This proves that the selectivity of OT towards each of the ions can be regulated simply by controlling the pH of the medium and hence allows the preparation of a sensing device with selectivity to Cu2+.

scholarly journals Sensor Based on a Poly[2-(Dimethylamino)ethyl Methacrylate-Co-Styrene], Gold Nanoparticles, and Methylene Blue-Modified Glassy Carbon Electrode for Melamine Detection

Sensors ◽  
2021 ◽  
Vol 21 (8) ◽  
pp. 2850
Author(s):  
Fairouz Aberkane ◽  
Imene Abdou ◽  
Nadia Zine ◽  
Nicole Jaffrezic-Renault ◽  
Abdelhamid Elaissari ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Gold Nanoparticles ◽  
Impedance Spectroscopy ◽  
Glassy Carbon Electrode ◽  
Modified Electrode ◽  
Glassy Carbon ◽  
Electrochemical Impedance ◽  
Differential Pulse ◽  
Carbon Electrode ◽  
Detection Range

Melamine has been used as a non-protein nitrogenous additive in food products to artificially increase the apparent “false” protein content. Melamine is known as a dangerous and poisonous substance for human health and it causes diverse diseases. An electrochemical sensor for melamine detection has been developed by modification of a glassy carbon electrode using copolymer poly[DMAEMA-co-styrene], gold nanoparticles, and methylene blue. The characterization of the modified electrode was conducted using several analysis techniques including cyclic voltammetry (CV), differential pulse voltammetry (DPV), chronoamperometry (CA), and electrochemical impedance spectroscopy (EIS). The electrochemical detection of melamine was performed by impedance spectroscopy. Obtained results revealed that the developed sensor has a large detection range from 5.0 × 10−13 to 3.8 × 10−8 M with a low detection limit of 1.8 × 10−12 M (at S/N = 3). Various interfering species such as phenol, hydroquinone, and bisphenol A have been used and their behavior on modified electrode has been studied.

scholarly journals Degradation Phenomena of Bismuth-Modified Felt Electrodes in VRFB Studied by Electrochemical Impedance Spectroscopy

Batteries ◽  
2019 ◽  
Vol 5 (1) ◽  
pp. 16 ◽  
Author(s):  
Jonathan Schneider ◽  
Eduard Bulczak ◽  
Gumaa El-Nagar ◽  
Marcus Gebhard ◽  
Paul Kubella ◽  
...  
Keyword(s):  
Electrochemical Impedance Spectroscopy ◽  
Impedance Spectroscopy ◽  
Electrochemical Impedance ◽  
Modified Electrodes ◽  
Impregnation Method ◽  
Carbon Felt ◽  
Half Cell ◽  
Negative Side ◽  
Prolonged Contact ◽  
Before And After

The performance of all-V redox flow batteries (VRFB) will decrease when they are exposed to dynamic electrochemical cycling, but also when they are in prolonged contact with the acidic electrolyte. These phenomena are especially severe at the negative side, where the parasitic hydrogen evolution reaction (HER) will be increasingly favored over the reduction of V(III) with ongoing degradation of the carbon felt electrode. Bismuth, either added to the electrolyte or deposited onto the felt, has been reported to suppress the HER and therefore to enhance the kinetics of the V(II)/V(III) redox reaction. This study is the first to investigate degradation effects on bismuth-modified electrodes in the negative half-cell of a VRFB. By means of a simple impregnation method, a commercially available carbon felt was decorated with Bi 2 O 3 , which is supposedly present as Bi(0) under the working conditions at the negative side. Modified and unmodified felts were characterized electrochemically using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) in a three-electrode setup. Surface morphology of the electrodes and composition of the negative half-cell electrolyte were probed using scanning electron microscopy (SEM) and X-ray fluorescence spectroscopy (TXRF), respectively. This was done before and after the electrodes were subjected to 50 charge-discharge cycles in a battery test bench. Our results suggest that not only the bismuth catalyst is dissolved from the electrode during battery operation, but also that the presence of bismuth in the system has a strong accelerating effect on electrode degradation.

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