Oxidation of chlorophenols on Pt electrode in alkaline solution studied by cyclic voltammetry, galvanostatic electrolysis, and gas chromatography­mass spectrometry

2001 ◽  
Vol 73 (12) ◽  
pp. 1929-1940 ◽  
Author(s):  
Z. Ezerskis ◽  
Z. Jusys
Keyword(s):  
Cyclic Voltammetry ◽  
Platinum Electrode ◽  
Rapid Decrease ◽  
Oxide Formation ◽  
Pt Electrode ◽  
Potential Region ◽  
Galvanostatic Electrolysis ◽  
Diffusion Limitations ◽  
Naoh Solution ◽  
And Diffusion

Potentiodynamic investigations on a platinum electrode show that oxidation of phenol, monochlorophenols, dichlorophenols, 2,3,6-, 2,4,5-, 2,4,6-trichlorophenols, and pentachlorophenol in 1 M NaOH solution, containing 1 mM of phenols, proceeds in the potential region of Pt oxide formation. The oxidation rate of phenols decreases with the increase in the number of chlorine atoms in the benzene ring in the row: phenol > monochlorophenols > dichlorophenols > trichlorophenols > pentachlorophenol. The electrochemical stability of phenols, as studied using a cyclic voltammetry, depends on their chlorination degree and isomerism. Galvanostatic oxidation of 1 M NaOH solutions containing 1 mM of phenol, monochlorophenols, dichlorophenols, 2,3,6-, 2,4,5-, 2,4,6-trichlorophenols, and pentachlorophenol were carried out on a platinum electrode using 30 mA cm­2 current density. The electrolysis of the solutions was performed in the course of 10 h, and concentration of phenols in the anolytes was monitored during oxidation. The concentration of phenolic compounds diminishes from 1 mM to 10­50 mM during 4­5 h of electrooxidation and does not change during further galvanostatic oxidation. A decrease in concentration of phenols during galvanostatic electrolysis weakly depends on the isomerism and a chlorination degree of the compounds. A rapid decrease in concentration of studied phenols during the first 4­5 h of electrolysis and a nonselective oxidation of different chlorophenols suggest that the oxidation proceeds via electrochemically generated oxidants. Further decrease in concentration of phenols is rather small due to deactivation of the electrode as a result of polymerization of corresponding phenols and diffusion limitations.

Enhanced Electrochemical Oxidation of BH4− on Pt Electrode in Alkaline Electrolyte with the Addition of Thiourea

2010 ◽  
Vol 132 ◽  
pp. 271-278 ◽  
Author(s):  
Dan Mei Yu ◽  
Chang Guo Chen ◽  
Shu Lei ◽  
Xiao Yuan Zhou ◽  
Guo Zhong Cao
Keyword(s):  
Cyclic Voltammetry ◽  
Electrochemical Oxidation ◽  
Electrochemical Impedance ◽  
Alkaline Electrolyte ◽  
Hydroxyl Groups ◽  
Catalytic Hydrolysis ◽  
Direct Oxidation ◽  
Pt Electrode ◽  
Separation Membrane ◽  
And Diffusion

The electrochemical oxidation of sodium borohydride (NaBH4) on Pt electrode in alkaline electrolyte with the addition of thiourea has been studied by means of cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and chronopotentiometry (CP). NaBH4 is readily to react with hydroxyl groups to release hydrogen through either direct oxidation or catalytic hydrolysis. The experimental results demonstrated that the addition of an appropriate amount of thiourea to the alkaline electrolyte resulted in the suppression of catalytic hydrolysis and diffusion of borohydride ions through the separation membrane.

scholarly journals Electrochemical Trifluoromethylation of Isonicotinic acid hydrazide using Cyclic Voltammetry and Galvanostatic Electrolysis

2018 ◽  
Vol 34 (4) ◽  
pp. 2098-2105
Author(s):  
Raja Beryl J ◽  
Joseph Raj Xavier
Keyword(s):  
Cyclic Voltammetry ◽  
Glassy Carbon ◽  
Current Density ◽  
Platinum Electrode ◽  
Isonicotinic Acid ◽  
Acid Hydrazide ◽  
Isonicotinic Acid Hydrazide ◽  
Glassy Carbon Electrodes ◽  
Galvanostatic Electrolysis ◽  
Sodium Trifluoroacetate

Trifluoromethylation of isonicotinic acid hydrazide has been investigated in trifluoroacetic acid containing pyridine, triethylamine and sodium trifluoroacetate dissolved in acetonitrile on platinum and glassy carbon electrodes using cyclic voltammetry. LSVs for isonicotinic acid hydrazide in 0.1 M TFA/ Py/TEA/NaTFA in acetonitrile on platinum electrode show that there is no distinct oxidation peak for the oxidation of isonicotinicacid hydrazide within the voltammetric region of 0.0 to 1.6 V vs Ag and it gets oxidized anodically in the gas evolution region itself. TFA/ NaTFA medium shows slightly higher current density than the other two media for the oxidation of isonicotinic acid hydrazide. CVs for different concentrations of isonicotinic acid hydrazide show that anodic peak becomes broad and flat. It shows that severe adsorption of INAH/product takes place on the glassy carbon electrode during the voltammetry scanning. Galvanostatic electrolysis of INAH in TFA/Py/ACN medium at low current density on Pt shows good conversion with low selectivity.

Electrochemical studies of N,N-bis pyrazinyl ­ 3,4,9,10 - perylenebis (dicarboximide) (PyPD ) on Pt electrode

2012 ◽  
Vol 16 (1) ◽  
pp. 53-57 ◽  
Author(s):  
E. H. El-Mossalamy ◽  
A. Y. Obaid ◽  
S. A. El-Daly ◽  
I. S. El-Hallag ◽  
A. M. Asiri ◽  
...  
Keyword(s):  
Cyclic Voltammetry ◽  
Platinum Electrode ◽  
Reaction Pathway ◽  
Digital Simulation ◽  
Simulation Method ◽  
Electrode Reaction ◽  
Electrochemical Studies ◽  
Tetrabutylammonium Perchlorate ◽  
Pt Electrode ◽  
Electrochemical Parameters

The electrochemical studies of N, N – bis(pyrazinyl) – 3, 4, 9, 10 – perylene bis (dicarboximide) (PyPD) dye has been carried out on Pt electrode using cyclic voltammetry and convolution deconvolution voltammetry combined with digital simulation technique at a platinum electrode in 0.1 mol L-1 tetrabutylammonium perchlorate (TBAP) in acetonitrile solvent (CH3CN). The compound under consideration was reduced via consumption of two sequential electrons to form radical anion and dianion (EE mechanism). The electrode reaction pathway and the electrochemical parameters of the investigated compound were determined using cyclic voltammetry and convolution – deconvolution transforms. The extracted electrochemical parameters were verified and confirmed via digital simulation method.

THE ADSORPTION OF BiIII/Pt NANOCOMPOSITES AT PLATINUM ELECTRODE WITH HIGHLY ENHANCED ELECTROCATALYSIS TOWARD GLUCOSE

2014 ◽  
Vol 21 (03) ◽  
pp. 1450042 ◽  
Author(s):  
ZHUOYUAN YANG ◽  
YUQING MIAO ◽  
TIANRUI WANG ◽  
MINGSHU XIAO ◽  
XIAOCAI LIANG ◽  
...  
Keyword(s):  
Cyclic Voltammetry ◽  
Active Site ◽  
Active Sites ◽  
Platinum Electrode ◽  
High Sensitivity ◽  
Glucose Detection ◽  
Pt Electrode ◽  
Positive Potential ◽  
Simple Method ◽  
Oxidation Of Glucose

In this paper, we first fabricated a nanoPt modified platinum electrode. Then through a simple method, the electrode surface was introduced with a submonolayer of bismuth that acted as an effective promoter. Cyclic voltammetry and other characterizations were employed. The obtained Bi III / nanoPt / Pt electrode exhibited two greatly increased oxidation peaks at negative and positive potential areas, respectively. The signals were far larger than that of platinum electrode because of the large true surface area of nanoparticles and the catalysis of bismuth adsorbed on platinum. In the presence of bismuth, the platinum active sites could combine with more OH - from bismuth hydroxyl to form a new active site for the oxidation of glucose. The prepared Bi III / nanoPt / Pt electrode given high sensitivity and excellent linearship to glucose detection and showed the potential application in the areas of electrocatalysis or electroanalysis.

scholarly journals Electrochemical Studies of o- and p- Anisidine

2015 ◽  
Vol 3 (2) ◽  
pp. 267-271
Author(s):  
Richa Sharma ◽  
Sushma Dave
Keyword(s):  
Cyclic Voltammetry ◽  
Electrochemical Oxidation ◽  
Platinum Electrode ◽  
Linear Sweep Voltammetry ◽  
Electrochemical Studies ◽  
Oxidation Peak ◽  
Cathodic Peak ◽  
Linear Sweep ◽  
And Diffusion ◽  
Sensitive Method

Electrochemical oxidation of methyl substituted aniline (anisidine) has been done on both gold and platinum electrode using cyclic voltammetry. The results were compared in different supporting electrolytes such as KCl, KNO3, H2SO4, HCl. Effect of pH was observed on electrochemical oxidation of o- & p- anisidine at gold and platinum electrode. During various scan single oxidation peak during first forward scan with no corresponding cathodic peak was obtained while a new anodic cathodic couple peak appears in subsequent scan obtained. Kinetic parameters like heterogeneous rate constant, transfer co-efficient and diffusion co-efficient were also calculated. A sensitive method was developed for estimation of micro quantities of anisidine by linear sweep voltammetry and hydrodynamic voltammetry.Int J Appl Sci Biotechnol, Vol 3(2): 267-271 DOI: http://dx.doi.org/10.3126/ijasbt.v3i2.12615 

Redox Potential - (Electronic) Structure Relationships in 18- and 17-Electron Mononitrile (or Monocarbonyl) Diphosphine Complexes of Re and Fe

2001 ◽  
Vol 66 (1) ◽  
pp. 139-154 ◽  
Author(s):  
M. Fátima C. Guedes Da Silva ◽  
Luísa M. D. R. S. Martins ◽  
João J. R. Fraústo Da Silva ◽  
Armando J. L. Pombeiro
Keyword(s):  
Cyclic Voltammetry ◽  
Electronic Structure ◽  
Binding Sites ◽  
Closed Shell ◽  
Carbonyl Complexes ◽  
Metal Centre ◽  
Pt Electrode ◽  
Metal Site ◽  
Oxidation Potentials ◽  
First Time

The organonitrile or carbonyl complexes cis-[ReCl(RCN)(dppe)2] (1) (R = 4-Et2NC6H4 (1a), 4-MeOC6H4 (1b), 4-MeC6H4 (1c), C6H5 (1d), 4-FC6H4 (1e), 4-ClC6H4 (1f), 4-O2NC6H4 (1g), 4-ClC6H4CH2 (1h), t-Bu (1i); dppe = Ph2PCH2CH2PPh2), or cis-[ReCl(CO)(dppe)2] (2), as well as trans-[FeBr(RCN)(depe)2]BF4 (3) (R = 4-MeOC6H4 (3a), 4-MeC6H4 (3b), C6H5 (3c), 4-FC6H4 (3d), 4-O2NC6H4 (3e), Me (3f), Et (3g), 4-MeOC6H4CH2 (3h); depe = Et2PCH2CH2PEt2), novel trans-[FeBr(CO)(depe)2]BF4 (4) and trans-[FeBr2(depe)2] (5) undergo, as revealed by cyclic voltammetry at a Pt-electrode and in aprotic non-aqueous medium, two consecutive reversible or partly reversible one-electron oxidations assigned as ReI → ReII → ReIII or FeII → FeIII → FeIV. The corresponding values of the oxidation potentials IE1/2ox and IIE1/2ox (waves I and II, respectively) correlate with the Pickett's and Lever's electrochemical ligand and metal site parameters. This allows to estimate these parameters for the various nitrile ligands, depe and binding sites (for the first time for a FeIII/IV couple). The electrochemical ligand parameter show dependence on the "electron-richness" of the metal centre. The values of IE1/2ox for the ReI complexes provide some supporting for a curved overall relationship with the sum of Lever's electrochemical ligand parameter. The Pickett parametrization for closed-shell complexes is extended now also to 17-electron complexes, i.e. with the 15-electron ReII and FeIII centres in cis-{[ReCl(dppe)2]}+ and trans-{FeBr(depe)2}2+, respectively.

Synthesis, Chemical Characterisation, and DNA Binding Studies of Ferrocene-Incorporated Selenoureas

2013 ◽  
Vol 66 (6) ◽  
pp. 626 ◽  
Author(s):  
Raja Azadar Hussain ◽  
Amin Badshah ◽  
Muhammad Nawaz Tahir ◽  
Bhajan Lal ◽  
Inayat Ali Khan
Keyword(s):  
Cyclic Voltammetry ◽  
Dna Binding ◽  
Atomic Absorption Spectrophotometry ◽  
Free Drug ◽  
X Ray Diffraction ◽  
Peak Potential ◽  
Binding Studies ◽  
Vis Spectroscopy ◽  
Dna Binding Studies ◽  
And Diffusion

In this article we have presented the synthesis, chemical characterisation (by NMR and FTIR spectroscopy, atomic absorption spectrophotometry, elemental analysis, and single crystal X-ray diffraction), electrochemistry, and DNA binding studies (with cyclic voltammetry, viscometry, and UV-vis spectroscopy) of six new ferrocene incorporated selenoureas. All the six compounds interact electrostatically with DNA which was evident by a negative shift in the cyclic voltammetry peak potential of the drug–DNA adduct relative to the free drug. The drug–DNA binding constant was calculated by a decrease in peak current after the addition of DNA to the free drug. We have also reported binding site sizes and diffusion coefficients of the synthesised compounds.

The Effect of Appending of I-，Fe2+ and MnO4- to the Electro-Oxidation of Methanol on Platinum Electrode

2012 ◽  
Vol 608-609 ◽  
pp. 894-897
Author(s):  
Hai Tao Wang ◽  
Zhen Jin ◽  
Yu Chun Qin
Keyword(s):  
Aqueous Solution ◽  
Electrode Surface ◽  
Platinum Electrode ◽  
Cyclic Voltammograms ◽  
Pt Electrode ◽  
Promotion Effect ◽  
Oxidation Current ◽  
Oxidation Of Methanol ◽  
Electronic Distribution ◽  
Electro Oxidation

Three kinds of ions (I-、Fe2+and MnO4-) were appended into the methanol aqueous solution respectively as an additive and the Cyclic voltammograms of the aqueous solutions were studied. The results showed that Fe2+had obvious promotion effect for electro-oxidation of methanol and could improve the methanol anodic oxidation current by 85 percent. The promotion effect of the thulium Ions were related with the electronic distribution of these elements and their adsorption on the Pt electrode surface. I-and MnO4-could facilitate the electro-oxidation of methanol at different extent.

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