Myoglobin on multi-walled carbon nanotubes modified electrode: direct electrochemistry and electrocatalysis

Electrochemical behavior of myoglobin (Myb) incorporated on multi-walled carbon nanotubes (MWNTs) modified GC electrode is investigated by electrochemical impedance spectroscopy (EIS) and cyclic voltarnmetry (CV). The results indicate that Myb can be strongly adsorbed on the surface of the MWNT-modified electrode to form an approximate monolayer film. MWNTs can greatly promote the redox of horse heart Myb, on which a pair of well-defined and nearly reversible CV peaks for Myb Fe(III)/ Fe(II) redox Couple were obtained in pH 7.0 buffers. The formal potential of Myb on MWNT modified electrode shifts linearly with pH with a slope of -56.4 mV/pH, showing that the electron transfer is accompanied by single proton transportation. The high efficiency of the Myb/MWNT modified electrode towards the catalytic electro-reduction of nitric oxide has been observed. Potential application of Myb/MWNT modified electrode as biosensors to monitor NO is proposed. (C) 2003 Elsevier B.V. All rights reserved.