THERMODYNAMICS AND KINETICS OF ADSORPTION AND ELECTROCATALYSIS OF NADH OXIDATION WITH A SELF-ASSEMBLING QUINONE DERIVATIVE

Platinum electrodes have been modified with the imine (I) derived from 3,4-dihydroxybenzaldehyde and 4-aminopyridine; a self-assembling material which incorporates an o-hydroquinone moiety, and a pyridine group. This material adsorbs strongly onto polycrystalline platinum electrodes through the pyridine nitrogen and the resulting modified electrodes retain the redox activity of the quinone/hydroquinone group. The thermodynamics as well as the kinetics of adsorption of this material onto platinum electrodes have been investigated and the apparent diffusion coefficient (D-app) has also been measured. The modified electrodes exhibit potent and relatively persistent electrocatalysis for NADH oxidation with a diminution of the overpotential of about 300 mV and the electrocatalytic current increases linearly with the NADH concentration from 0.2 mM to 2.0 mM.