title: Membrane/mediator-free rechargeable enzymatic biofuel cell utilizing graphene/single-wall carbon nanotube cogel electrodes.
abstract: Enzymatic biofuel cells (EBFCs) utilize enzymes to convert chemical energy present in renewable biofuels into electrical energy and have shown much promise in the continuous powering of implantable devices. Currently, however, EBFCs are greatly limited in terms of power and operational stability with a majority of reported improvements requiring the inclusion of potentially toxic and unstable electron transfer mediators or multicompartment systems separated by a semipermeable membrane resulting in complicated setups. We report on the development of a simple, membrane/mediator-free EBFC utilizing novel electrodes of graphene and single-wall carbon nanotube cogel. These cogel electrodes had large surface area (∼ 800 m(2) g(-1)) that enabled high enzyme loading, large porosity for unhindered glucose transport and moderate electrical conductivity (∼ 0.2 S cm(-1)) for efficient charge collection. Glucose oxidase and bilirubin oxidase were physically adsorbed onto these electrodes to form anodes and cathodes, respectively, and the EBFC produced power densities up to 0.19 mW cm(-2) that correlated to 0.65 mW mL(-1) or 140 mW g(-1) of GOX with an open circuit voltage of 0.61 V. Further, the electrodes were rejuvenated by a simple wash and reloading procedure. We postulate these porous and ultrahigh surface area electrodes will be useful for biosensing applications, and will allow reuse of EBFCs.
authors: Department of Biomedical Engineering, Carnegie Mellon University , 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213, United States.
authors: Alan S
authors: AS
authors: Campbell
authors: Yeon Joo
authors: YJ
authors: Jeong
authors: Steven M
authors: SM
authors: Geier
authors: Richard R
authors: RR
authors: Koepsel
authors: Alan J
authors: AJ
authors: Russell
authors: Mohammad F
authors: MF
authors: Islam
mesh_terms: D001674:Bioelectric Energy Sources; D056804:Biofuels / Q000032:analysis*; D004560:Electricity; D004566:Electrodes; D004579:Electron Transport; D005949:Glucose Oxidase / Q000737:chemistry*; D006108:Graphite / Q000737:chemistry*; D037742:Nanotubes, Carbon / Q000737:chemistry*; D044925:Oxidoreductases Acting on CH-CH Group Donors / Q000737:chemistry*
chemical_list: D056804:Biofuels; D037742:Nanotubes, Carbon; D006108:Graphite; D005949:Glucose Oxidase; D044925:Oxidoreductases Acting on CH-CH Group Donors; C042401:bilirubin oxidase
keywords: aerogel; biofuel cell; enzymes; glucose; graphene; single-walled carbon nanotubes