Development of an enzymatic cathode biofuel cell using laccase

Enzymatic biofuel cells are an attractive alternative for renewable electricity generation. In this work, we are focusing on the cathodic compartment of a biofuel cell using laccase, a multi-copper oxidase, as biocatalysts for the oxygen reduction reaction (ORR) by direct electron transfer of electrons. Several strategies have been used to optimize the kinetic of ORR on graphite electrode. One strategy was to deposit thin film of amorphous carbon nitride (a-CNx) on graphite. The presence of surface amine groups then allowed the covalent grafting of the laccase. Carboxylic groups can also be produced by an electrochemical treatment. By combining several characterisation techniques, especially impedance measurements, we have demonstrated that our system behaves like microelectrodes network. For this type of electrode, we have measured a maximal current density equal to -44,6 μA/cm². In another strategy, the surface of graphite was nanostructured by forming carbon nanowalls (CNWs) using the plasma-enhanced chemical vapour deposition technique in a CO/H₂ microwave discharge. We have optimized then the APPJ functionalization conditions using experiments design. We reached current densities of the order of -1 mA/cm². We have also studied the orientation and the kinetic of enzyme immobilisation on gold surface using PM-IRRAS technique. (author)