Anthraquinone-modified carbon electrodes

The surface chemical effects of interest do not go as far as those induced in (extensively) modified carbon electrodes [248], e.g., by pyrolyzed phthalocyanines or macrocycles [249-255], by anthraquinone or its derivatives [126,247,256-259], or by aryl groups [125], or those of stable and efficient sonoelectrocatalysts by modifying GC electrodes with 9,10-phenanthraquinone or 1,2-naphthoquinone [260], Instead, it is explored here whether and how a seemingly simple but crucial issue has been addressed or resolved what makes 02 adsorption in ORR nondissociative The isotopic labeling evidence for this experimental fact has been presented half a century ago [261], and it has not been challenged [262], The implication, based on the equally noncontrover-sial literature that 02 chemisorption on carbons (even at room temperature) is dissociative, is summarized below ... 

The following asymmetrical PsC capacitor was studied as a typical example of a redox capacitor. 1,2-dihydroxybenzene (DHB also referred to as o-benzoquinone and catechol) obtained by modification of a carbon electrode was used in it as a positive electrode. The negative electrode used was an anthraquinone (AQ)-modified carbon electrode (Algharaibeh and Pickup, 2011). 

R.C., and Pal, R. (2013) Cyclic voltammetric investigation of caffeine at anthraquinone modified carbon paste electrode. International Journal of Electrochemistry,... 

Salimi, A., Banks, C.E., and Compton, R.G. (2003). Ultrasonic effects on the electroreduction of oxygen at a glassy carbon anthraquinone-modified electrode. The Koutecky-Levich equation applied to insonated electrocatalytic reactions. Phys. Chem. Chem. Phys., 5, 3988-93. 

A Spectracarb 2225 carbon fabric (Engineered Fibres Technologies) was used as a basis for the synthesis of an AQ-modified carbon cloth (C-AQ) electrode. This cloth was immersed into the salt of anthraquinone-1-diazonium chloride 0.5 ZnCl2 in acetone. Then, water and 50 wt% hypophosphorous acid were added. Then, the thus-modified cloth was washed by deionized water and dried at 110°C for 20 min. 

As mentioned above, the pretreatment of the carbon electrode surface can significantly affect its ORR activity, and even alter the ORR mechanism. Actually, the carbon surface can also be modified by some monolayer substances such as anthraquinones (AQ), and transition metal macrocycle complexes. Due to the conjugate structures of these molecules, they can irreversibly adsorb on the carbon surface to form monolayers that could serve as an electrocatalyst for ORR. This kind of electrode structure can be used to evaluate the electrocatalyst s ORR activity, particularly in acidic solution. 

Algharaibeh, Z. and P. G. Pickup, 2011. An asymmetric supercapacitor with anthraquinone and dihydroxybenzene modified carbon fabric electrodes. Electrochemistry Communications, 13,147-149. 

Sarapuu A, Vaik K, Schiffrin DJ, Tammeveski K. Electrochemical reduction of oxygen on anthraquinone modified glassy carbon electrodes in alkaline solution. J Electroanal Chem 2003 541 23-9. 

Salimi A, Eshghi H, Sharghi H, Golabi SM, Shamsipur M. Electrocataljrtic reduction of dioxygen at the surface of glassy carbon electrodes modified by some anthraquinone substituted podands. Electroanalysis 1999 11 114—9. 

Valarselvan S, Manisankar P (2011) Electrocatalytic reduction of oxygen at glassy carbon electrode modified by polypyrrole/anthraquinones composite film in various pH media. Electrochim Acta 56(20) 6945-6953... 

Tiwari 1, Singh M, Gupta M, Aggarwal SK (2012) Electroanalytical properties and appUcation of anthraquinone derivative-functionalized multiwalled carbon nanotubes nanowires modified glassy carbon electrode in the determination of dissolved oxygtai. Mater Res Bull 47 (7) 1697-1703. doi 10.1016/j.materresbull.2012.03.031... 

Maia G, Maschion FC, Tanimoto ST, Vaik K, Miieoig U, Tammeveski K (2007) Attachment of anthraquinone derivatives to glassy carbon and the electrocatalytic behavior oft he modified electrodes toward oxygen reduction. J Solid State Electrochem 11 1411-1420... 

Manisankar P, Gomathi A (2005) Electrocatalytic reductimi of dioxygen at the surface of carbon paste electrodes modified with 9,10-anthraquinone derivatives and dyes. Etectroanal-ysis 17(12) 1051-1057. doi 10.1002/elan.200403213... 

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