Formation of mediated biocatalytic cathodes by electrodeposition of a redox polymer and laccase

Mediated biocatalytic cathodes were fabricated via electrodeposition of an osmium-based redox polymer onto planar and porous electrode surfaces, incorporating the oxygen-reducing enzyme laccase. After one hour of electrodeposition time, bio-cathodes on glassy carbon substrate exhibited redox site loading of 6 nmol cm−2 and oxygen reduction current density of 1.4 mA cm−2. Those on carbon-fiber paper exhibited redox site loading of 46 nmol cm−2 and oxygen reduction current density of 15.7 mA cm−2. The current density and polarization behavior were comparable to those of bio-cathodes made by conventional chemical crosslinking. The specific activity in terms of current per mole of redox polymer or enzyme was significantly higher for electrodeposited films.