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MM: Fachverband Metall- und Materialphysik
MM 31: Postersitzung II
MM 31.8: Poster
Wednesday, March 16, 2011, 17:15–18:45, P5
Evaluation of perovskite oxides as oxygen evolving catalyst for photocatalytic water splitting — •Daniel Mierwaldt1, Jörg Hoffmann1, Bruno Jasper1, Christian Jooß1, Stephanie Raabe1, Sven Schnittger1, and Simone Techert2 — 1Institut für Materialphysik, Universität Göttingen — 2MPI für biophysikalische Chemie, Göttingen
In search for suitable water splitting catalysts, several oxide materials have already been successfully investigated. However, most of them have band gaps in the UV-region limiting the efficiency in light harvesting. Perovskite manganites represent a promising material class, in which strong electron-lattice coupling results in a broad polaronic absorption band from visible light to near-IR. In addition, multilevel excitation into long-living polaronic states may contribute to high chemical potentials of electron-hole pairs, exceeding the band gap of the respective material.
In this contribution the strongly correlated CaMnO3 has been investigated, which reveales a rather large exchange current density of about 1,9 mA/cm2. Bulk samples as well as epitaxial grown thin films on Nb-doped SrTiO3 substrate were investigated by means of cyclic voltammetry. The samples were used as working anode in a photocatalytic apparatus with Pt-counter cathode in Na2SO4-electrolyte.
A complementary approach to water splitting is the use of nano composites forming two dimensional patterns of pn-junctions. First results on the photocatalytic activity of Nb-doped SrTiO3 (n-type) mixed with off-stoichiometric CoFe2O4 (p-type) are presented.