An innovative powerful and mediatorless H2/O2 biofuel cell based on an outstanding bioanode

A H2/O2 biofuel cell based on a hyperthermophilic O2-tolerant hydrogenase and bilirubin oxidase was designed by one step covalent immobilization of the enzymes on functionalized carbon nanotubes. Under pure H2 and O2 saturated buffer solutions and no redox mediator, the biofuel cell delivers power densities up to 300μWcm−2 at 0.6V with an open circuit voltage of 1.1V. These performances, which are demonstrated to be dependent on hydrogenase characteristics at high potentials, are the best ever obtained. Promising stability of the biofuel cell during 24h of continuous use has been obtained, which allows considering this device as an alternative power supply for small portable applications. [Display omitted] ► Mediatorless H2/O2 biofuel cell based on O2-tolerant hydrogenase and bilirubin oxidase. ► Covalent enzyme immobilization on carbon nanotubes ► Hydrogenase characteristics at high potential determine the cell performance. ► Delivering of 300μWcm−2 power density at 0.6V with an OCV of 1.1V