title: Electrode-assisted catalytic water oxidation by a flavin derivative.
abstract: The success of solar fuel technology relies on the development of efficient catalysts that can oxidize or reduce water. All molecular water-oxidation catalysts reported thus far are transition-metal complexes, however, here we report catalytic water oxidation to give oxygen by a fully organic compound, the N(5)-ethylflavinium ion, Et-Fl(+). Evolution of oxygen was detected during bulk electrolysis of aqueous Et-Fl(+) solutions at several potentials above +1.9 V versus normal hydrogen electrode. The catalysis was found to occur on glassy carbon and platinum working electrodes, but no catalysis was observed on fluoride-doped tin-oxide electrodes. Based on spectroelectrochemical results and preliminary calculations with density functional theory, one possible mechanistic route is proposed in which the oxygen evolution occurs from a peroxide intermediate formed between the oxidized flavin pseudobase and the oxidized carbon electrode. These findings offer an organic alternative to the traditional water-oxidation catalysts based on transition metals.
authors.affiliation: Department of Chemistry, Bowling Green State University, Bowling Green, Ohio                 43403, USA.
authors.forename: Ekaterina
authors.initials: E
authors.lastname: Mirzakulova
authors.forename: Renat
authors.initials: R
authors.lastname: Khatmullin
authors.forename: Janitha
authors.initials: J
authors.lastname: Walpita
authors.forename: Thomas
authors.initials: T
authors.lastname: Corrigan
authors.forename: Nella M
authors.initials: NM
authors.lastname: Vargas-Barbosa
authors.forename: Shubham
authors.initials: S
authors.lastname: Vyas
authors.forename: Shameema
authors.initials: S
authors.lastname: Oottikkal
authors.forename: Samuel F
authors.initials: SF
authors.lastname: Manzer
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Hadad
authors.forename: Ksenija D
authors.initials: KD
authors.lastname: Glusac
mesh_terms: D002244:Carbon / Q000737:chemistry; D002384:Catalysis; D055664:Electrochemical Techniques; D004566:Electrodes; D005415:Flavins / Q000737:chemistry*; D010084:Oxidation-Reduction; D010100:Oxygen / Q000737:chemistry; D010984:Platinum / Q000737:chemistry; D014867:Water / Q000737:chemistry*
chemical_list: D005415:Flavins; D014867:Water; D010984:Platinum; D002244:Carbon; D010100:Oxygen