Electrode-assisted catalytic water oxidation by a flavin derivative.

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.

[1]  Qiushi Yin,et al.  A Fast Soluble Carbon-Free Molecular Water Oxidation Catalyst Based on Abundant Metals , 2010, Science.

[2]  W. R. Salaneck,et al.  Electroluminescence in conjugated polymers , 1999, Nature.

[3]  Susan W. Gersten,et al.  Catalytic oxidation of water by an oxo-bridged ruthenium dimer , 1982 .

[4]  Daniel G. Nocera,et al.  In Situ Formation of an Oxygen-Evolving Catalyst in Neutral Water Containing Phosphate and Co2+ , 2008, Science.

[5]  Stephen W. Feldberg,et al.  A Simulator for Cyclic Voltammetric Responses , 1994 .

[6]  A. Becke,et al.  Density-functional exchange-energy approximation with correct asymptotic behavior. , 1988, Physical review. A, General physics.

[7]  F. Castellano,et al.  Luminescent charge-transfer platinum(II) metallacycle. , 2007, Inorganic chemistry.

[8]  N. Lewis,et al.  Designing electronic/ionic conducting membranes for artificial photosynthesis , 2011 .

[9]  G. Dismukes,et al.  Synthetic Water-Oxidation Catalysts for Artificial Photosynthetic Water Oxidation. , 1997, Chemical reviews.

[10]  S. Bernhard,et al.  Fast water oxidation using iron. , 2010, Journal of the American Chemical Society.

[11]  Y. Liu,et al.  Nitrogen-doped graphene as efficient metal-free electrocatalyst for oxygen reduction in fuel cells. , 2010, ACS nano.

[12]  Robin Brimblecombe,et al.  Molecular water-oxidation catalysts for photoelectrochemical cells. , 2009, Dalton transactions.

[13]  J. Sauvage,et al.  Synthesis and Study of Mononuclear Ruthenium(II) Complexes of Sterically Hindering Diimine Chelates. , 1986 .

[14]  J. McCauley,et al.  Synthesis and characterization of C60O, the first fullerene epoxide , 1992 .

[15]  T. Fuller,et al.  Kinetic model of the electrochemical oxidation of graphitic carbon in acidic environments. , 2009, Physical chemistry chemical physics : PCCP.

[16]  Jacopo Tomasi,et al.  Molecular Interactions in Solution: An Overview of Methods Based on Continuous Distributions of the Solvent. , 1995 .

[17]  J. Howard,et al.  Identification of C20H10 Dicyclopentapyrenes in Flames: Correlation with Corannulene and Fullerene Formation , 1996 .

[18]  R BoerdeF.,et al.  Electronic properties of U2Cu9Al , 1999 .

[19]  Harry B Gray,et al.  Powering the planet with solar fuel. , 2009, Nature chemistry.

[20]  D. T. Sawyer,et al.  Effects of media and electrode materials on the electrochemical reduction of dioxygen , 1982 .

[21]  Parr,et al.  Development of the Colle-Salvetti correlation-energy formula into a functional of the electron density. , 1988, Physical review. B, Condensed matter.

[22]  J. Sauvage,et al.  Synthesis and study of mononuclear ruthenium(II) complexes of sterically hindering diimine chelates. Implications for the catalytic oxidation of water to molecular oxygen , 1986 .

[23]  Hong-Qing He,et al.  Reaction of C60 with oxygen adatoms on Pt(111) , 1999 .

[24]  R. Thummel,et al.  A new family of Ru complexes for water oxidation. , 2005, Journal of the American Chemical Society.

[25]  Ardemis A. Boghossian,et al.  Photoelectrochemical complexes for solar energy conversion that chemically and autonomously regenerate , 2010, Nature chemistry.

[26]  Antoni Llobet,et al.  Molecular catalysts that oxidize water to dioxygen. , 2009, Angewandte Chemie.

[27]  David Milstein,et al.  Consecutive Thermal H2 and Light-Induced O2 Evolution from Water Promoted by a Metal Complex , 2009, Science.

[28]  A. Vogler,et al.  Water splitting by light with osmocene as photocatalyst. , 2009, Angewandte Chemie.

[29]  Javier J. Concepcion,et al.  Mechanism of water oxidation by single-site ruthenium complex catalysts. , 2010, Journal of the American Chemical Society.

[30]  Daniel G. Nocera,et al.  A self-healing oxygen-evolving catalyst. , 2009, Journal of the American Chemical Society.

[31]  S. Bernhard,et al.  Cyclometalated iridium(III) Aquo complexes: efficient and tunable catalysts for the homogeneous oxidation of water. , 2008, Journal of the American Chemical Society.

[32]  T. Van Voorhis,et al.  Electronic design criteria for O-O bond formation via metal-oxo complexes. , 2008, Inorganic chemistry.

[33]  Javier J. Concepcion,et al.  Catalytic and surface-electrocatalytic water oxidation by redox mediator-catalyst assemblies. , 2009, Angewandte Chemie.

[34]  D. Sazou,et al.  Reversible One-Electron Generation of 4a,5-Substituted Flavin Radical Cations: Models for a Postulated Key Intermediate in Bacterial Bioluminescence. , 1988 .

[35]  Samuel F. Manzer,et al.  Mechanism of N(5)-ethyl-flavinium cation formation upon electrochemical oxidation of N(5)-ethyl-4a-hydroxyflavin pseudobase. , 2010, The journal of physical chemistry. B.

[36]  Thomas F. Jaramillo,et al.  Identification of Active Edge Sites for Electrochemical H2 Evolution from MoS2 Nanocatalysts , 2007, Science.

[37]  F. Du,et al.  Nitrogen-Doped Carbon Nanotube Arrays with High Electrocatalytic Activity for Oxygen Reduction , 2009, Science.

[38]  T. Moore,et al.  Solar fuels via artificial photosynthesis. , 2009, Accounts of chemical research.

[39]  Clyde W. Cady,et al.  Functional Models for the Oxygen-Evolving Complex of Photosystem II. , 2008, Coordination chemistry reviews.

[40]  N. S. Sariciftci,et al.  Conjugated polymer-based organic solar cells. , 2007, Chemical reviews.

[41]  G. Brudvig,et al.  A functional model for O-O bond formation by the O2-evolving complex in photosystem II. , 1999, Science.

[42]  T. Mallouk,et al.  Template electrodeposition of single-phase p- and n-type copper indium diselenide (CuInSe2) nanowire arrays. , 2011, ACS nano.

[43]  M. Olivucci,et al.  Fast excited-state deactivation in N(5)-ethyl-4a-hydroxyflavin pseudobase. , 2011, The journal of physical chemistry. B.

[44]  Licheng Sun,et al.  Evolution of O2 in a seven-coordinate Ru(IV) dimer complex with a [HOHOH]- bridge: a computational study. , 2010, Angewandte Chemie.

[45]  N. Lewis,et al.  Powering the planet: Chemical challenges in solar energy utilization , 2006, Proceedings of the National Academy of Sciences.

[46]  Feng Liu,et al.  Mechanisms of water oxidation from the blue dimer to photosystem II. , 2008, Inorganic chemistry.

[47]  Dirk C. Mattfeld,et al.  A Computational Study , 1996 .

[48]  Peter J. F. Harris,et al.  Structure of non-graphitising carbons , 1997 .