Carbon electrodes organic electrochemistry

Carbon electrodes are widely used in electrochemistry both in the laboratory and on the industrial scale. The latter includes production of aluminium, fluorine, and chlorine, organic electrosynthesis, electrochemical power sources, etc. Besides the use of graphite (carbons) as a virtually inert electode material, the electrochemical intercalation deserves special attention. This topic will be treated in the next paragraph. 

Y.Z. Guo and A.R. Guadalupe, Direct electrochemistry of horseradish peroxidase adsorbed on glassy carbon electrode from organic solutions. Chem. Commun. 15, 1437-1438 (1997). 

Carapiica, H.M., Balula, M.S., Fonseca, and A.P., Cavaleiro, A.M.V. 2006. Electrochemical characterization of glassy carbon electrodes modified with hybrid inorganic-organic single layer of a-kegging type polyoxotung states. Journal of Solid State Electrochemistry 10, 10-17. 

Together with carbon, mercury is one of the most attractive electrode materials. It has high proton reduction overpotential and a very well-defined and smooth surface. For these reasons it has been widely used as electrode material in organic electrochemistry. The preparation of mercury microelectrodes has thus been an interesting and challenging problem that has been addressed by several groups (29-31). The technique of making mercury... 

An exciting prospect in synthetic organic electrochemistry is the selective synthesis of specific optical isomers by taking advantage of the asymmetry afforded by certain types of surface sites achieved with chemically modified electrode surfaces on substrates such as carbon. 

C6IT4O2) A yellow crystalline organic compound with a pungent odor. Its molecules contain a non-aromatic six-carbon ring and it behaves as an unsaturated diketone with conjugated double bonds. It is used in making dyestuffs. A platinum electrode in an equimolar solution of quinone and hydroquinone (benzene-l,4-diol, CgH4(OH)2) is used as a standard electrode in electrochemistry. The reaction is ... 

Svancara, I. and Zima, J. (2011) Possibilities and limitations of carbon paste electrodes in organic electrochemistry (a review). Curr. Org. Chem., 15, 3043-3058. 

Y. Guo, A. R. Guadalupe, Direct Electrochemistry of Horseradish Peroxidase Adsorbed on Glassy Carbon Electrode from Organic Solution. Chem. Commun., (1997) 1437-1438. 

Wang XL, Wang EB, Lan Y, Hu CW (2002) Renewable PMol2-based inorganic-organic hybrid material bulk-modified carbon paste electrode preparation, electrochemistry and electrocatalysis. Electroanalysis 14 1116-1121... 

CNT randomly dispersed composites Many soft and rigid composites of carbon nanotubes have been reported [17]. The first carbon-nanotube-modified electrode was made from a carbon-nanotube paste using bromoform as an organic binder (though other binders are currently used for the paste formation, i.e. mineral oil) [105]. In this first application, the electrochemistry of dopamine was proved and a reversible behavior was found to occur at low potentials with rates of electron transfer much faster than those observed for graphite electrodes. Carbon-nanotube paste electrodes share the advantages of the classical carbon paste electrode (CPE) such as the feasibility to incorporate different substances, low background current, chemical inertness and an easy renewal nature [106,107]. The added value with CNTs comes from the enhancement of the electron-transfer reactions due to the already discussed mechanisms. 

The term modified electrodes encompasses a broad variety of electrode materials obtained by attaching a monomolecular layer of a specific compound on the surface of a conducting solid [338]. In electrocatalysis, modified electrodes are common in the field of oxygen reduction, where carbon materials can be modified for example by attaching layers of macrocycles. Modified electrodes are very common in the field of molecular or supramolecular electrochemistry, especially in the organic area. 

Carbon fiber electrode - Edison produced the first carbon fibers by carbonization of cotton threads in 1879. Today polyacrylonitrile (as well as Rayon and various other organic precursors) is the most common precursor for carbon fiber formation [i]. Carbonization of polyacrylonitrile is carried out at 1500 °C to give highly electrically conducting fibers with 5-10 pm diameter. Fibers carbonized at up to 2500 °C are more graphitic with a carbon content of >99%. Carbon fiber-based materials have found many applications due to their exceptionally high tensile strength. In electrochemistry carbon fiber -> micro electrodes are very important in analytical detection [ii] and for in vivo electrochemical studies [iii]. Carbon fiber textiles are employed in - carbon felt electrodes. 

The most popular electrode materials for reduction are mercury, lead, titanium, and platinum. The choice of anode is limited because most metals are anodically corroded. In the laboratory, most of the electrodes are made of platinum, gold, or carbon. Exotic anodes such as lead dioxide or DSA (Dimensionally Stable Anode such as Ti/Ru02) have been developed for organic or chlorine electrochemistry. 

Porous carbon materials are used for many applications in various industrial or domestic domains adsorption (air and water purification, filters manufacture, solvents recovery), electrochemistry (electrodes for batteries, supercapacitors, fuel cells), catalyst support (industrial chemistry, organic synthesis, pollutants elimination),. .. Porous carbons used at the present time are generally activated carbons, i.e. materials prepared by pyrolysis of natural sources, like fhiit pits, wood or charcoal. Pyrolysis is followed by a partial oxidation, under steam or CO2 for instance, leading to the development of the inner porosity. 

---