Cobalt glassy carbon electrodes

Electrocatalysis employing Co complexes as catalysts may have the complex in solution, adsorbed onto the electrode surface, or covalently bound to the electrode surface. This is exemplified with some selected examples. Cobalt(I) coordinatively unsaturated complexes of 2,2 -dipyridine promote the electrochemical oxidation of organic halides, the apparent rate constant showing a first order dependence on substrate concentration.1398,1399 Catalytic reduction of dioxygen has been observed on a glassy carbon electrode to which a cobalt(III) macrocycle tetraamine complex has been adsorbed.1400,1401... 

M.S. Lin and B.I. Jan, Determination of hydrogen peroxide by utilizing a cobalt(II)hexacyanoferrate-modified glassy carbon electrode as a chemical sensor. Electroanalysis 9, 340-344 (1997). 

J.Z. Zhang and S.J. Dong, Cobalt(II)hexacyanoferrate film modified glassy carbon electrode for construction of a glucose biosensor. Anal. Lett. 32, 2925—2936 (1999). 

The electrooxidation of hydrazine is also catalysed by metal compounds other than oxides, as shown by Hou et al. using an FI manifold. They employed a cobalt tetraphenylporphyrin-modified glassy carbon electrode to oxidize hydrazine at +0.5 V vj Ag/AgCl and pH 2.5, and achieved a detection limit of 0.1 ng [194]. 

An aluminum electrode modified by a chemically deposited palladium pen-tacyanonitrosylferrate film was reported in [33]. Vitreous carbon electrode modified with cobalt phthalocyanine was used in [34]. Electrocatalytic activity of nanos-tructured polymeric tetraruthenated porphyrin film was studied in [35]. Codeposition of Pt nanoparticles and Fe(III) species on glassy-carbon electrode resulted in significant catalytic activity in nitrite oxidation [36]. It was shown that the pho-tocatalytic oxidation at a Ti02/Ti film electrode can be electrochemically promoted [37]. 

Luz, R. D. S., Damos, F. S., Tanaka, A. A. and Kubota, L. T. (2006), Dissolved oxygen sensor based on cobalt tetrasulphonated phthalocyanine immobilized in poly-L-lysine film onto glassy carbon electrode. Sensor Actuator B Chem., 114(2) 1019-1027. 

Finally, US-enhanced mass transport has also been found to influence the rate of metal deposition (e.g. that of cobalt on glassy carbon electrodes by cyclic and stripping voltammetry, and chronoamperometry [157]). 

Abbreviations GOx-glucose oxidase HRP-horse radish peroxidase PAMAM-poly(arnidoamine) Gn - generation number CPE-carbon paste electrode GCE-glassy carbon electrode ITO-indium-tin oxide CoHCF-cobalt hexacyanoferrate K M - apparent Michaelis-Menten constant LbL-layer-by-layer SAM-self-assembled monolayer... 

Figure 1. SEM images of different electrodeposited metal oxide nanoparticles Ti02 nanotube arrays grown on Ti substrate(a) cobalt oxide nanoparticles onto glassy carbon electrode (b) nickel oxide nanoparticles(c) and zinc oxide nanoparticles Reproduced from references [ 138],[ 102],[ 137] and [135] with permission from Elsevier.

Figure 33. (A) CV response of GC electrode modified with CoOx Nanoparticles in pH 12 solutions at v = 20 mVs 1 (B) SEM image of the electrodeposited CoOx on GC electrode. Reprinted from Analytica Chimica Acta, 594, A. Salimi, R. Hallaj, H. Mamkhezri, S. Soltanian, Nanomolar detection of hydrogen peroxide on glassy carbon electrode modified with electrodeposited cobalt oxide nanoparticles,26,Copyrights(2007) and J. Electroanalytical Chemistry, 619-620, A. Salimi, R.Hallaj, H. MamKhezri, S.M.T. Hosaini, Electrochemical properties and electrocatalytic activity of FAD immobilized onto cobalt oxide nanoparticles Application to nitrite detection,33, Copyrights (2008) with permission from Elsevier.

Figure 35. UV-visible spectra of catalase in PBS (pH 7) phosphate buffer solution (curve A) and Hb-CoOx film on ITO electrode (curveB).(B) CVs of glassy carbon electrode modified with cobalt oxide nanoparticles (a) and Glassy carbon electrode modified with cobalt oxide nanoparticles and Hb (b), electrolyte is PBS (pH7), scan rate is 100 mVs Reprinted from Biophysical Chemistry, 62, A.Salimi, R. Hallaj, S. Soltanian, Immobilization of hemoglobin on electrodeposited cobalt-oxide nanoparticles Direct voltammetry and electrocatalytic activity,124,125, Copyrights(2007) with permission from Elsevier.

FIGURE 3.9 Linewaver-Burke plots of 1A vs. 1/c, from rotating disk voltammograms recorded for OC (squares) and p (rhombs) cobalt cordierite-modified glassy carbon electrodes (GCEs) in contact with a 1.25 mM mannitol plus 1.0 M NaOH aqueous solution. Potential scan rate. 50 mV/sec. 

Cataldi, T.R.L, Guerrieri, A., Casella, LG., and Desimoni, E. 1995. Study of a cobalt-based surface modified glassy carbon electrode Electrocatalytic oxidation of sugars and alditols. Electroanalysis 7, 305-311. 

Magdesieva, T.V., T. Yamamoto, D.A. Tryk, and A. Fujishima (2002). Electrochemical reduction of CO2 with transition metal phthalocyanine and porphyrin complexes supported on activated carbon fibers. J. Electrochem. Soc. 149(6), D89-D95. Atoguchi, T., A. Aramata, A. Kazusaka, and M. Enyo (1991). Cobalt (II)-tetraphenylporphyrin-pyridine complex fixed on a glassy carbon electrode and its prominent catalytic activity for reduction of carbon dioxide. J. Chem. Soc. Chem. Commun. 13, 156-157. 

Aga, H., A. Aramata, and Y. Hisaeda (1997). The electroreduction of carbon dioxide by macrocyclic cobalt complexes chemically modified on a glassy carbon electrode. 

Mafatle, T. and T. Nyokong (1997). The use of cobalt(II) phthalocyanine to improve the sensitivity and stability of glassy carbon electrodes for the detectuon of cresols, chlorophenols and phenol. Anal. Chim. Acta 354, 307-314. 

Bottger, B., U. Schindewolf, J.L. Avila, and R. Rodrfguez-Amaro (1997). Catalytic electrodeposition of silver on glassy carbon electrodes modified with films of cobalt phthalocyanine. J. Electroanal. Chem. 432, 139-144. 

Salimi, A., Hallaj, R., Soltanian, S. Fabrieation of a sensitive Cholesterol Biosenscnr based on cobalt oxide nanostructures electrodeposited onto glassy carbon electrode. Electroanalysis 21(24), 2693-2700 (2009)... 

Luz, R.C.S., Moreira, A.B., Damos, F.S., Tanaka, A.A., Kubota, L.T. Cobalt tetrasulphonated phthalocyanine immobilized on poly-L-lysine film onto glassy carbon electrode as amperometric sensor for cysteine. J. Pharm. Biomed. Anal. 42, 184—191 (2006). doi 10.1016/j. jpba.2006.03.036... 

D Souza F, Hsieh Y, Deviprasad GR (1998) Four-electrrai electrocatalytic reduction of dioxygen to water by an ion-pair cobalt porphyrin dimer adsorbed on a glassy carbon electrode. Chem Commun 9 1027-1028... 

---