Rapid determination of kinetic parameters for the electrocatalytic reduction of dioxygen by vitamin B12 adsorbed on glassy carbon electrode

✍ Scribed by Qingsheng Qiu; Shaojun Dong

• Publisher: Elsevier Science
• Year: 1993
• Tongue: English
• Weight: 604 KB
• Volume: 38
• Category: Article
• ISSN: 0013-4686
• DOI: 10.1016/0013-4686(93)80112-d

✦ Synopsis

In this paper, the electrochemical behavior of vitamin B,, , ie cyanocobalamin (abbr. VB,,) in a weak acidic aqueous solution and adsorbed on glassy carbon (GC) surface (abbr. VB,,(ad)/GC) in different pH buffer solutions have been described by using cyclic voltammetry (cv). It is found that VB,, and VB,,(ad)/GC exhibit catalytic activity for the electroreduction of 0, according to two reduction peaks at -0.50 and -l.OOV vs. see; but their electrocatalytic activity is very unstable. Baaed on the method of hydrodynamic amperometry [B. Miller and S. Bruckenstein, J. electrochem. Sot. 117, 1033 (1970)], some kinetic parameters for the electrocatalytic reduction of 0, by VB,,(ad)/GC have been determined rapidly by using a linear rotation-scan method [Rongzhong Jiang and Shaojun Dong, Elecnochim. Acta 35, 1451 (1990)]. These kinetic parameters indicate that the reduction of 0, on VB,,(ad)/GC gives water predominantly in both potential ranges which correspond to those two reduction peaks. Possible reaction mechanisms have bee-n suggested.