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Gabrielsson, Roger

Glowacki, Eric

Gryszel, Maciej

Heiss, Wolfgang

Jakesova, Marie

Romanazzi, Giuseppe

Sytnyk, Mykhailo

English

Low-cost semiconductor photocatalysts offer unique possibilities for industrial chemical transformations and energy conversion applications. We report that a range of organic semiconductors are capable of efficient photocatalytic oxygen reduction to H2O2 in aqueous conditions. These semiconductors, in the form of thin films, support a 2-electron/2-proton redox cycle involving photoreduction of dissolved O-2 to H2O2, with the concurrent photooxidation of organic substrates: formate, oxalate, and phenol. Photochemical oxygen reduction is observed in a pH range from 2 to 12. In cases where valence band energy of the semiconductor is energetically high, autoxidation competes with oxidation of the donors, and thus turnover numbers are low. Materials with deeper valence band energies afford higher stability and also oxidation of H2O to O-2. We found increased H2O2 evolution rate for surfactant-stabilized nanoparticles versus planar thin films. These results evidence that photochemical O-2 reduction may be a widespread feature of organic semiconductors, and open potential avenues for organic semiconductors for catalytic applications.Funding Agencies|Wallenberg Center for Molecular Medicine at Linkoping University; "Aufbruch Bayern" initiative of the state of Bavaria</p

Academic Archive On-line (Linköping University, Sweden)

General Observation of Photocatalytic Oxygen Reduction to Hydrogen Peroxide by Organic Semiconductor Thin Films and Colloidal Crystals

Low-cost semiconductor
photocatalysts offer unique possibilities for industrial chemical
transformations and energy conversion applications. We report that
a range of organic semiconductors are capable of efficient photocatalytic
oxygen reduction to H2O2 in aqueous conditions.
These semiconductors, in the form of thin films, support a 2-electron/2-proton
redox cycle involving photoreduction of dissolved O2 to
H2O2, with the concurrent photooxidation of
organic substrates: formate, oxalate, and phenol. Photochemical oxygen
reduction is observed in a pH range from 2 to 12. In cases where valence
band energy of the semiconductor is energetically high, autoxidation
competes with oxidation of the donors, and thus turnover numbers are
low. Materials with deeper valence band energies afford higher stability
and also oxidation of H2O to O2. We found increased
H2O2 evolution rate for surfactant-stabilized
nanoparticles versus planar thin films. These results evidence that
photochemical O2 reduction may be a widespread feature
of organic semiconductors, and open potential avenues for organic
semiconductors for catalytic applications

Maciej Gryszel (1609771)

Mykhailo Sytnyk (1292802)

Marie Jakešová (5087951)

Giuseppe Romanazzi (613598)

Roger Gabrielsson (1525978)

Wolfgang Heiss (1269912)

Eric Daniel Głowacki (1320084)

FigShare

General
Observation of Photocatalytic Oxygen Reduction to Hydrogen Peroxide
by Organic Semiconductor Thin Films and Colloidal Crystals

Digitala Vetenskapliga Arkivet - Academic Archive On-line

Moorhead State Teachers College

Minnesota State University, Moorhead