Electrocatalytic activity of [Ru(bpy)3]2+ for hypoxanthine oxidation studied by rotating electrode methods

A rotating ring-disk electrode method for studying the electrochemical oxidation of hypoxanthine (Hx) catalyzed by [Ru(bpy)3]3+/2+ reaction has been developed. A limiting current plateau for [Ru(bpy)3]3+/2+ reaction is exhibited on the rotating disk or ring electrode. It is found that [Ru(bpy)3]2+ has excellent electrocatalytic activities for Hx oxidation. The electrocatalytic currents increase linearly with the rise of Hx concentrations in the range from 0.2 to 1.2 mmol/L on the immobile Pt electrode. Whereas, high rotation rate or Hx concentration makes the voltammetric curves on the rotating disk electrode display the sharp peaks instead of the limiting current plateaus. The oxidized mechanisms of Hx catalyzed by Ru(bpy)33+/2+ reaction are discussed in detail.