Cubic phase Sr2FeNbO6 (SFNO) particles were synthesized and studied experimentally for visible light photocatalysis. The photocatalytic activity for hydrogen (2 times) and oxygen (1.1 times) evolution was very high, as compared to that for PbBi2Nb2O9 (visible light active photocatalysts). As a qualitative guiding tool, a density functional theory study of cubic SFNO demonstrates that the valence band consists of O2p hybridized with Nb-states and possibly Fe 3d states (Fe 3dx 2 -y 2 , Fe 3dz 2), while the conduction band mainly consists of Sr 4d states, possibly with Nb 4d as its minima. In particular, the intermediate prominent existence of the Fe d- orbital expectedly renders a high coefficient of absorption making SFNO a potential visible light active photocatalyst. The qualitative correlation of the experimental results and computed electronic structure affirms its suitability for visible light applications.
Keywords: Sr2FeNbO6, Visible light photocatalysis, Hydrogen evolution, Electronic-structure, Photocatalytic activity.