Biofuel cells and their development

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Description/Abstract

A biofuel cell electrochemical system based on the oxidation of glucose by glucose oxidase has been developed. The glucose oxidase was immobilised at the electrode surface by a cast Nafion polymer membrane neutralised and modified by tetrabutylammonium bromide to stabilise the membrane. Electrochemical communication with the electrode was established with ferrocene derivatives in solution or co-cast with the Nafion. The individual and combined properties of the components of the system were investigated to select the best components to create a biofuel cell.

After establishing a functioning biofuel cell a scale-up procedure was followed in which the chemical system was transferred to higher area electrodes. A laboratory prototype biofuel cell was designed and used to test larger 3-d electrode materials. Before use as an electrochemical reactor the flow properties of the test cell and electrodes were investigated by pulse injections of concentrated buffer tracked with an inline conductivity probe.

The biofuel cell generated a steady state power density of up to 50 μW cm-2 superficial area at a graphite plate electrode or 6 μW cm-2 (actual surface basis) at a reticulated vitreous carbon electrode. The test cell demonstrated high cell potentials for a biofuel cell based on a single enzyme electrode and gave a stable output for several days.