Electropolymerization of aniline and some of its derivatives

1989 ◽  
Vol 54 (12) ◽  
pp. 3154-3161 ◽  
Author(s):  
Ludmila Dempírová ◽  
Zdena Adamcová
Keyword(s):  
Polymer Films ◽  
Electrochemical Behaviour ◽  
Oxidation Mechanism ◽  
Single Layer ◽  
Amino Group ◽  
Methyl Substituent ◽  
Pt Electrode ◽  
Pt Electrodes ◽  
Electro Oxidation ◽  
Acetonitrile Medium

The effect of substitution on the aromatic ring of aniline and in its amino group on the potential of polymerization in aqueous medium and on the charge passed during polymerization was studied. The formation of polymer films on the working electrode and their electrochromic changes were also examined. From the electro-oxidation of aniline, the number of reversible and irreversible steps, the number of electrons exchanged and the type of oxidation mechanism were found. Thickness of a single layer of polyaniline, formed by cycling the potential in the range –0.2 V, +1.4 V(vs SCE) at a polarization rate of 5 mV/s, was estimated considering the oxidation mechanism of aniline. The electrochemical behaviour of aniline in anhydrous acetonitrile medium was also studied. It was found by blocking the m- and p-positions in aniline by a methyl substituent that polymerization of aniline occurs through the p-position. The porosity of the polymer films was estimated from the diffusion coefficient values for 1.10-3M K3[Fe(CN)]6 in 0.1M-KCl calculated from the Randles-Sevcik equation for measurements on Pt electrodes with a polymer film, compared with the tabulated values for a bare Pt electrode.

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

Electrochemical and ATR-FTIR study of dimethyl ether and methanol electro-oxidation on sputtered Pt electrode

2007 ◽  
Vol 52 (19) ◽  
pp. 5781-5788 ◽  
Author(s):  
Yan Liu ◽  
Masashi Muraoka ◽  
Shigenori Mitsushima ◽  
Ken-Ichiro Ota ◽  
Nobuyuki Kamiya
Keyword(s):  
Dimethyl Ether ◽  
Pt Electrode ◽  
Ftir Study ◽  
Electro Oxidation

Dynamic instabilities during the continuous electro-oxidation of CO on poly- and single crystalline Pt electrodes

2009 ◽  
Vol 603 (10-12) ◽  
pp. 1646-1651 ◽  
Author(s):  
Sauradip Malkhandi ◽  
Antoine Bonnefont ◽  
Katharina Krischer
Keyword(s):  
Oxidation Of Co ◽  
Single Crystalline ◽  
Pt Electrodes ◽  
Electro Oxidation

Multi-Layer Coating of Ultrathin Polymer Films on Nanoparticles of Alumina by a Plasma Treatment

2001 ◽  
Vol 635 ◽  
Author(s):  
Donglu Shi ◽  
Zhou Yu ◽  
S. X. Wang ◽  
Wim J. van Ooij ◽  
L. M. Wang ◽  
...  
Keyword(s):  
Plasma Treatment ◽  
Polymer Films ◽  
Ultrathin Films ◽  
Plasma Polymerization ◽  
Single Layer ◽  
Process Time ◽  
Transmission Electron ◽  
Ultrathin Polymer Films ◽  
Secondary Ion ◽  
Layer Coating

AbstractMulti-layer ultrathin polymer films have been deposited on the surfaces of nanoparticles of alumina using a plasma polymerization treatment. The nanoparticles ranged from 10-150 nm in spherical shapes. High-resolution transmission electron microscopy (HRTEM) experiments showed that an extremely thin film of the pyrrole layer (10-20 Å) was uniformly deposited on the surfaces of the nanoparticles. In particular, the particles of all sizes (10-150 nm) exhibited equally uniform ultrathin films indicating well-dispersed nanoparticles in the fluidized bed during the plasma treatment. After single layer coating, hexamethyldisiloxane (HMDSO) was coated again as a second layer onto the surface of pyrrole. Subsequently, a third layer of pyrrole was coated on the top of HMDSO film completing the multi-layer coating process. Time-of-Flight Secondary ion mass spectroscopy (TOFSIMS) experiments confirmed the deposition of these multi-layer thin films on the nanoparticles. The deposition mechanisms and the effects of plasma treatment parameters are discussed.

Electrochemical behaviour of basal single crystal Pt electrodes in alkaline medium

1990 ◽  
Vol 288 (1-2) ◽  
pp. 217-228 ◽  
Author(s):  
Emilia Morallón ◽  
José Luis Vázquez ◽  
Antonio Aldaz
Keyword(s):  
Single Crystal ◽  
Alkaline Medium ◽  
Electrochemical Behaviour ◽  
Pt Electrodes

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.

Sign in / Sign up

Export Citation Format

Share Document