Castelli, Ivano Eligio2; Thygesen, Kristian Sommer3; Jacobsen, Karsten Wedel2
1 Center for Atomic-scale Materials Design, Center, Technical University of Denmark2 Department of Physics, Technical University of Denmark3 Center for Nanostructured Graphene, Center, Technical University of Denmark
We use density functional theory calculations to investigate the stability of cubic perovskites for photo-electrochemical water splitting taking both materials in their bulk crystal structure and dissolved phases into account. The method is validated through a detailed comparison of the calculated and experimental Pourbaix diagrams for TiO2 and ZnO. For a class of 23 oxides, oxynitrides, and oxyfluorides, which were recently proposed as candidates for one-photon water splitting, our calculations predict most of the materials to be stable at potentials around the water red-ox level. The oxides become less stable at lower potentials, while the oxynitrides become unstable at higher potentials. We discuss the implications of these findings for the problem of photo-corrosion of water splitting electrodes.
Topics in Catalysis, 2014, Vol 57, Issue 1-4, p. 265-272