A compact electrode assembly for voltammetric measurements with solid electrodes

1986 ◽  
Vol 323 (3) ◽  
pp. 238-240 ◽  
Author(s):  
Kurt Kalcher
Keyword(s):  
Solid Electrodes ◽  
Voltammetric Measurements

Effect of Ultrasound on Voltammetric Measurements on a Miniaturized Mercury Electrode; Sonovoltammetry and Sonopolarography

1996 ◽  
Vol 61 (12) ◽  
pp. 1703-1708 ◽  
Author(s):  
Ladislav Novotný
Keyword(s):  
Mercury Electrode ◽  
Solid Electrodes ◽  
Voltammetric Measurements

The influence of ultrasound on voltammetric measurements at a mechanically stable renewed mercury electrode was described. The measurements were carried out in a solution of 4,4'-bipyridyl in 0.1 M KCl + 0.01 M NaOH, in 1 . 10-4 M CdSO4 + 5 . 10-6 M tribenzylamine in 0.1 M H2SO4 and in 3 . 10-3 M CdSO4 + 1 . 10-4 M tribenzylamine hydrochloride. Possible development and applications of related electroanalytical techniques by using mercury and solid electrodes were discussed. A pronounced influence of ultrasound was observed mainly in cases where the kinetics and irreversibility of the electrochemical and related processes played an important role.

Marcus-Hush Theory Revealed by Electron Tunneling Through Hexagonal Boron Nitride

2019 ◽  
Author(s):  
Matěj Velický ◽  
Sheng Hu ◽  
Colin R. Woods ◽  
Peter S. Toth ◽  
Viktor Zólyomi ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Boron Nitride ◽  
Electron Tunneling ◽  
Hexagonal Boron Nitride ◽  
Large Body ◽  
Liquid Solution ◽  
Limiting Current ◽  
Electron Transfer Rate Constant ◽  
Electrochemical Parameters ◽  
Voltammetric Measurements

Marcus-Hush theory of electron transfer is one of the pillars of modern electrochemistry with a large body of supporting experimental evidence presented to date. However, some predictions, such as the electrochemical behavior at microdisk electrodes, remain unverified. Herein, we present a study of electron tunneling across a hexagonal boron nitride barrier between a graphite electrode and redox levels in a liquid solution. This was achieved by the fabrication of microdisk electrodes with a typical diameter of 5 µm. Analysis of voltammetric measurements, using two common redox mediators, yielded several electrochemical parameters, including the electron transfer rate constant, limiting current, and transfer coefficient. They show a significant departure from the Butler-Volmer behavior in a clear manifestation of the Marcus-Hush theory of electron transfer. In addition, our system provides a novel experimental platform, which could be applied to address a number of scientific problems such as identification of reaction mechanisms, surface modification, or long-range electron transfer.

scholarly journals Low-Temperature Mineralisation of Titania-Siloxane Composite Layers

Catalysts ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 50
Author(s):  
Tomáš Svoboda ◽  
Michal Veselý ◽  
Radim Bartoš ◽  
Tomáš Homola ◽  
Petr Dzik
Keyword(s):  
Low Temperature ◽  
Great Influence ◽  
Gel Permeation Chromatography ◽  
Photocatalytic Decomposition ◽  
Acid Orange 7 ◽  
Composite Layers ◽  
Nonthermal Treatment ◽  
Plasma Methods ◽  
Voltammetric Measurements ◽  
Thermally Treated

This paper deals with low-temperature mineralisation of coatings made with titania-siloxane compositions (TSC). Methyltriethoxysilane has been adopted as the precursor for the siloxane, and during its synthesis, an oligomeric siloxane condensate with methyl moieties acting as TiO2 binder has been produced. These methyl moieties, contained in TSC, provide solubility and prevent gelling, but reduce the hydrophilicity of the system, reduce the transfer of electrons and holes generated in the TiO2. In order to avoid these unfavourable effects, TSC mineralisation can be achieved by nonthermal treatment, for example, by using UV-radiation or plasma treatment. Characterisation of the siloxane was performed by gel permeation chromatography (GPC), which showed the size of the siloxane chain. Thermogravimetric analysis revealed a temperature at which the siloxane mineralises to SiO2. Printed layers of two types of TSC with different siloxane contents were studied by a scanning electron microscope (SEM), where a difference in the porosity of the samples was observed. TSC on fluorine-doped tin oxide (FTO) coated glass and microscopic glass were treated with non-thermal UV and plasma methods. TSC on FTO glass were tested by voltammetric measurements, which showed that the non-thermally treated layers have better properties and the amount of siloxane in the TSC has a great influence on their efficiency. Samples on microscopic glass were subjected to a photocatalytic decomposition test of the model pollutant Acid orange 7 (AO7). Non-thermally treated samples show higher photocatalytic activity than the raw sample.

Role of Catalyst in Controlling N2 Reduction Selectivity: A Unified View of Nitrogenase and Solid Electrodes

ACS Catalysis ◽  
2021 ◽  
pp. 6596-6601
Author(s):  
Alexander Bagger ◽  
Hao Wan ◽  
Ifan E. L. Stephens ◽  
Jan Rossmeisl
Keyword(s):  
Unified View ◽  
Solid Electrodes

scholarly journals Recent Advances in the Use of Transition-Metal Porphyrin and Phthalocyanine Complexes as Electro-Catalyst Materials on Modified Electrodes for Electroanalytical Sensing Applications

Solids ◽  
2021 ◽  
Vol 2 (2) ◽  
pp. 212-231
Author(s):  
J. Antonio Cruz-Navarro ◽  
Fabiola Hernández-García ◽  
Luis Humberto Mendoza-Huizar ◽  
Verónica Salazar-Pereda ◽  
J. Ángel Cobos-Murcia ◽  
...  
Keyword(s):  
Transition Metal ◽  
Catalytic Properties ◽  
Modified Electrodes ◽  
Metal Porphyrin ◽  
Water Contaminants ◽  
Active Behavior ◽  
Sensing Applications ◽  
Redox Active ◽  
Innovative Materials ◽  
Solid Electrodes

Metalloporphyrins (MP) and metallophtalocyanines (MPc) are innovative materials with catalytic properties that have attracted attention for their application for diverse electrochemical purposes. The presence of metallic centers in their structure offers a redox-active behavior that is being applied in the design of solid electrodes for the quantification of biomolecules, water contaminants, and pharmaceuticals, among others. Herein, we collect the recent information about porphyrin and phthalocyanine complexes as modifiers of electrodes, and the important aspects of the design, characterization, and application of these electrodes.

Synthesis, characterisation and activity in catalytic epoxidation of olefins of new dinuclear nickel(ll) complexes

2009 ◽  
Vol 2009 (8) ◽  
pp. 527-532
Author(s):  
Manindranath Bera
Keyword(s):  
Visible Region ◽  
Chemical Oxidation ◽  
Cyclic Voltammetric ◽  
Catalytic Epoxidation ◽  
Redox Couples ◽  
Square Planar ◽  
Catalytically Active ◽  
Mecn Solution ◽  
Voltammetric Measurements ◽  
Epoxidation Of Olefins

Two new dinuclear nickel(ll) compounds of formula [Nill2(μ-L1)2](CIO4)2·MeCN (1·MeCN) and [NiII2(μ-L2)2](CIO4)2 (2) where HL1 and HL2 stand for 3-(2-(dimethylamino)ethylimino)butan-2-one oxime and 1-(2-(dimethylamino)ethyl-imino)-1-phenylpropan-2-one oxime respectively, have been synthesised. Single crystal X-ray analyses of the complexes reveal that the nickel(ll) ions are in square-planar N3O environments and form six-membered (NiNO)2 metallacycles. Cyclic voltammetric measurements of 1·MeCN and 2 in MeCN solution show quasirreversible one-electron oxidations at E1/2 = 0.566 V and 0.603 V ( vs Fc+/Fc), respectively, attributed to NiIIINiII/NiII2 redox couples. Additional reversible NiIII2/NiIIINiII redox responses were observed at relatively higher potential near E1/2 = 0.832 V and 0.850 V ( vs Fc+/Fc), respectively, for 1·MeCN and 2. Complexes 1·MeCN and 2 display intense charge-transfer bands at ∼390 and ∼345 nm in the visible region. Chemical oxidation of complex 1·MeCN by sodium hexachloroiridate(IV) hexahydrate generates red Ni2III species with characteristic new bands at ∼520 and 427 nm in the visible region as well as the characteristic EPR signals at 77 K with g⊥ > gII. Similar phenomena were observed for complex 2 upon chemical oxidation. The dinickel(ll) complexes are catalytically active for epoxidation of olefins using iodosylbenzene as the terminal oxidant.

Voltammetric measurements with microelectrodes in low-conductivity systems

1987 ◽  
Vol 220 (1) ◽  
pp. 31-40 ◽  
Author(s):  
M.J. Peña ◽  
M. Fleischmann ◽  
N. Garrard
Keyword(s):  
Voltammetric Measurements
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