Berlin 2012 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 24: Functional Materials II
MM 24.1: Vortrag
Dienstag, 27. März 2012, 11:30–11:45, H 1029
Tunable optical bandgap of polymeric carbon nitride photocatalysts — •Christoph Merschjann, Tobias Tyborski, Steven Orthmann, Florent Yang, Martha Christina Lux-Steiner, and Thomas Schedel-Niedrig — Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Berlin, Germany
Polymeric carbon nitrides with the approximate sum formula C3N4 have been shown to be photocatalytically active for hydrogen production from water under visible light illumination.
For an effective sunlight-driven process, the bandgap of the catalyst should be in the range of 2 eV.
We have investigated the optical bandgap of carbon nitride polymers synthesized at different temperatures between 400 ∘C and 610 ∘C.
The bandgaps are found to be linearly decreasing in the given temperature range, parallel to a decrease of the lattice constants of the polymer network.
Thus, a tunability is given in the range 2.5 eV < Egdir < 3.0 eV.
Possible reasons for the observed effects are discussed in the presentation.