Iron (III) nanocomposites for enzyme-less biomimetic cathode: A promising material for use in biofuel cells

In this paper, we discuss the synthesis and electrochemical properties of a new material based on iron oxide nanoparticles stabilized with poly(diallyldimethylammonium chloride) (PDAC): this material can be used as a biomimetic cathode material for the reduction of H2O in biofuel cells. A metastable phase of iron oxide and iron hydroxide nanoparticles (PDAC-FeOOH/Fe2O3-NPs) was synthesized through a single procedure. On the basis of the Stokes-Einstein equation, colloidal particles (diameter: 20 nm) diffused at a considerably slow rate (D=0.9 x 10(-11) m s(-1)) as compared to conventional molecular redox systems. The quasi-reversible electrochemical process was attributed to the oxidation and reduction of Fe3+/Fe2+ from PDAC-FeOOH/Fe2O3-NPs; in a manner similar to redox enzymes, it acted as a pseudo-prosthetic group. Further, PDAC-FeOOH/Fe2O3-NPs was observed to have high electrocatalytic activity for H2O2 reduction along with a significant overpotential shift, Delta E=0.68 V from -0.29 to 0.39 V. in the presence and absence of PDAC-FeOOH/Fe2O3-NPs. The abovementioned iron oxide nanoparticles are very promising as candidates for further research on biomimetic biofuel cells, suggesting two applications: the preparation of modified electrodes for direct use as cathodes and use as a supporting electrolyte together with H2O2. (C) 2010 Elsevier B.V. All rights reserved.