Département de chimie moléculaire

We report on an alternative concept of biofuel cell functioning based on the unconventional use of enzymes to create a pH difference generating a p.d. between electrodes soaked in quinhydrone solns. The electrode and quinhydrone soln. were confined in a dialysis bag placed into a compartment contg. either glucose oxidase and catalase for the biocathode or urease for the bioanode. In presence of 0.4 mol L-1 glucose and urea, the enzyme reactions generate a pH difference of 3.55, both compartments being sepd. by an agar-agar wall. The resulting biofuel cell exhibits an open-circuit voltage and max. power of 208 mV and 30.6 $μ$W, resp., without immobilization and elec. connection of the involved enzymes. In addn., this biofuel cell was able to provide continuously 10 $μ$A during 23 h, producing 0.133 J and 0.828 C. A similar biofuel cell configuration based only on dialysis bags was also developed. A graphite disk electrode elaborated by mech. compression of graphite particles and quinhydrone, was placed in a dialysis bag itself confined into another dialysis bag contg. enzyme soln. The resulting power and open-circuit voltage at satg. substrate conditions are 7.6 $μ$W and 157 mV, resp. [on SciFinder(R)]