Reduction of horse heart ferricytochrome c at platinum and gold electrodes modified by various ad-atoms

Abstract

The electrochemical behaviour of cytochrome c was examined on platinum and gold electrodes modified by various ad-atom species (Cu, Ag, Hg, Sn, As, Sb, Bi, S, Se and Te). It was found that direct electron transfer occurs between cytochrome c molecules and platinum electrodes modified by Ag, Sn and S ad-atoms or gold electrodes modified by Ag, Hg, Sn, Sb, S and Se. The enhancement effects caused by these ad-atoms exhibit maxima at a coverage between 0.35 and 0.45. The primary effect caused by ad-atoms results from the suppression of the strong bond strength of cytochrome c molecules to the surface, and the secondary effect results from the electrostatic attraction.