Deposition of Cu onto polycrystalline Pt electrode from acidic CuSO4 solution in the presence of H2SeO3

2003 ◽  
Vol 81 (6) ◽  
pp. 199-206 ◽  
Author(s):  
Dijana Šimkūnaitė ◽  
Antanas Steponavičius ◽  
Vitalija Jasulaitienė ◽  
Eimutis Matulionis
Keyword(s):  
Pt Electrode ◽  
Cuso4 Solution

Nucleation and growth of Cu onto polycrystalline Pt electrode from acidic CuSO4 solution in the presence of H2SeO3

2005 ◽  
Vol 10 (7) ◽  
pp. 447-457 ◽  
Author(s):  
Dijana Šimkūnaitė ◽  
Emilija Ivaškevič ◽  
Aleksandras Kaliničenko ◽  
Antanas Steponavičius
Keyword(s):  
Nucleation And Growth ◽  
Pt Electrode ◽  
Cuso4 Solution

Effects of Doping on the Electrochemical and Electrical Properties of Poly(2,5-di(2-thienyl)pyrrole)

1999 ◽  
Vol 64 (8) ◽  
pp. 1357-1368 ◽  
Author(s):  
Enric Brillas ◽  
José Carrasco ◽  
Ramon Oliver ◽  
Francesc Estrany ◽  
Víctor Ruiz
Keyword(s):  
Mass Spectrometry ◽  
Fast Atom Bombardment ◽  
Oxidation Potential ◽  
Ethanolic Solution ◽  
Pt Electrode ◽  
Reversible Process ◽  
Oxidation Potentials ◽  
Lower Productivity ◽  
Polymeric Chains ◽  
Linear Molecules

The electropolymerization of 2,5-di(2-(thienyl)pyrrole) (SNS) on a Pt electrode from ethanolic solution with LiClO4 or LiCl as electrolyte has been studied by cyclic voltammetry (CV) and chronoamperometry (CA). In both media, a quasi-reversible process has been indicated by CV, reversing the scan at low oxidation potentials. Under these conditions, reducible positive charges formed in both oxidized polymers are compensated by the entrance of anions from solution. Elemental analysis reveals that polymers generated at a low oxidation potential by CA contain a 21.03% (w/w) of ClO4- or a 9.56% (w/w) of Cl-. The poly(SNS) doped with Cl- presents higher proportion of reducible positive charges, higher polymerization charge and lower productivity. A much higher electrical conductivity, however, has been found for the poly(SNS) doped with ClO4-. Both polymers are soluble in DMSO, acetone and methanol. The dimer, trimer, tetramer and pentamer have been detected as soluble and neutral linear oligomers by mass spectrometry-fast atom bombardment. The analysis of polymers by infrared spectroscopy confirms the predominant formation of linear molecules with α-α linkages between monomeric units. A condensation mechanism involving one-electron oxidation of all electrogenerated linear and neutral polymeric chains is proposed to explain the SNS electropolymerization.

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.

scholarly journals Mixed Lithium and Sodium Ion Aprotic DMSO Electrolytes for Oxygen Reduction on Au and Pt Studied by DEMS and RRDE

2021 ◽  
Author(s):  
M. Hegemann ◽  
P. P. Bawol ◽  
A. Köllisch-Mirbach ◽  
H. Baltruschat
Keyword(s):  
Oxygen Reduction ◽  
Product Distribution ◽  
Reduction Reaction ◽  
Mixed Electrolytes ◽  
Peroxide Formation ◽  
Pt Electrode ◽  
Rate Determining Step ◽  
Differential Electrochemical Mass Spectrometry ◽  
Redox Couples ◽  
Pt Electrodes

AbstractIn order to advance the development of metal-air batteries and solve possible problems, it is necessary to gain a fundamental understanding of the underlying reaction mechanisms. In this study we investigate the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER, from species formed during ORR) in Na+ containing dimethyl sulfoxide (DMSO) on poly and single crystalline Pt and Au electrodes. Using a rotating ring disk electrode (RRDE) generator collector setup and additional differential electrochemical mass spectrometry (DEMS), we investigate the ORR mechanism and product distribution. We found that the formation of adsorbed Na2O2, which inhibits further oxygen reduction, is kinetically favored on Pt overadsorption on Au. Peroxide formation occurs to a smaller extent on the single crystal electrodes of Pt than on the polycrystalline surface. Utilizing two different approaches, we were able to calculate the heterogeneous rate constants of the O2/O2− redox couple on Pt and Au and found a higher rate for Pt electrodes compared to Au. We will show that on both electrodes the first electron transfer (formation of superoxide) is the rate-determining step in the reaction mechanism. Small amounts of added Li+ in the electrolyte reduce the reversibility of the O2/O2− redox couples due to faster and more efficient blocking of the electrode by peroxide. Another effect is the positive potential shift of the peroxide formation on both electrodes. The reaction rate of the peroxide formation on the Au electrode increases when increasing the Li+ content in the electrolyte, whereas it remains unaffected on the Pt electrode. However, we can show that the mixed electrolytes promote the activity of peroxide oxidation on the Pt electrode compared to a pure Li+ electrolyte. Overall, we found that the addition of Li+ leads to a Li+-dominated mechanism (ORR onset and product distribution) as soon as the Li+ concentration exceeds the oxygen concentration. Graphical abstract

scholarly journals Immobilization of Pt nanoparticles on hydrolyzed polyacrylonitrile-based nanofiber paper

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Soon Yeol Kwon ◽  
EunJu Ra ◽  
Dong Geon Jung ◽  
Seong Ho Kong
Keyword(s):  
Particle Size ◽  
Uniform Distribution ◽  
Pt Nanoparticles ◽  
Electrochemical Activity ◽  
Aggregate Formation ◽  
Free Standing ◽  
Pt Electrode ◽  
Catalytic Current ◽  
Nucleation Sites ◽  
Hydrolysis Of

AbstractThe electrochemical activity of catalysts strongly depends on the uniform distribution of monodisperse Pt nanoparticles without aggregates. Here, we propose a new hydrolysis-assisted smearing method for Pt loading on a free-standing paper-type electrode. Polyacrylonitrile (PAN)-based nanofiber paper was used as the electrode, and it acted as a Pt support. Hydrolysis of the electrode tripled the number of active nucleation sites for Pt adsorption on the PAN nanofibers, thereby significantly enhancing the wettability of the nanofibers. This facilitated the uniform distribution of Pt nanoparticles without aggregate formation up to 40 wt% (about 0.8 mg/cm2) with a particle size of about 3 nm. The catalytic current of the hydrolyzed Pt electrode in CH3OH/H2SO4 solution exceeded 213 mA/cm2 Pt mg, which was considerably greater than the current was 148 mA/cm2 Pt mg for an unhydrolyzed electrode.

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.

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