title: Oxygen is electroreduced to water on a "wired" enzyme electrode at a lesser overpotential than on platinum.
abstract: The first enzyme-based catalyst that is superior to platinum in the four-electron electroreduction of oxygen to water is reported. The smooth Pt cathode reached half and 90% of the mass transport-limited current density at respective overpotentials of -0.4 and -0.58 V in 0.5 M sulfuric acid, and only at even higher overpotentials in pH 7.2 phosphate buffer. In contrast, the smooth "wired" bilirubin oxidase cathode reached half and 90% of the mass transport-limited current density at respective overpotentials as low as -0.2 and -0.25 V. The mass transport-limited current density for the smooth "wired" enzyme cathode in PBS was twice that with smooth Pt in 0.5 M sulfuric acid. Under 1 atm O2 pressure, O2 was electroreduced to water on a polished carbon cathode, coated with the "wired" BOD film, in pH 7.2 saline buffer (PBS) at an overpotential of -0.31 V at a current density of 9.5 mA cm-2. At the same overpotential, the current density of the polished platinum cathode in 0.5 M H2SO4 was 16-fold lower, only 0.6 mA cm-2.
authors.affiliation: Department of Chemical Engineering, Texas Materials Institute, University of Texas, Austin, TX 78712, USA.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Mano
authors.forename: Jose L
authors.initials: JL
authors.lastname: Fernandez
authors.forename: Yousung
authors.initials: Y
authors.lastname: Kim
authors.forename: Woonsup
authors.initials: W
authors.lastname: Shin
authors.forename: Allen J
authors.initials: AJ
authors.lastname: Bard
authors.forename: Adam
authors.initials: A
authors.lastname: Heller
mesh_terms: D001487:Basidiomycota / Q000201:enzymology; D004566:Electrodes; D010084:Oxidation-Reduction; D044925:Oxidoreductases Acting on CH-CH Group Donors / Q000737:chemistry*; D010100:Oxygen / Q000737:chemistry*; D010984:Platinum / Q000737:chemistry*; D014867:Water / Q000737:chemistry*
chemical_list: D014867:Water; D010984:Platinum; D044925:Oxidoreductases Acting on CH-CH Group Donors; C042401:bilirubin oxidase; D010100:Oxygen