A Green, Low-Cost and Efficient Photocatalyst: Atomic-Hydrogenated α-FeO.

The environmental-friendly hematite iron oxide (α-FeO) has important application prospects in the photocatalysis field owing to its narrow indirect band gap. Here, we report a band gap engineering of α-FeO by incorporation of electrochemically-generated atomic hydrogen at moderate conditions. The ultraviolet-visible spectra show the reduction of the α-FeO band gap after hydrogenation and the absorption region from 200-800 nm is enhanced, especially in the visible light region. First principles calculation reveals the mixing of the new hybrid energy level with the valence band top resulting in a decrease in the band gap of α-FeO. Further photocatalytic degradation experiments of dyes demonstrate that the photocatalytic efficiency of α-FeO can be greatly enhanced by the atomic hydrogen incorporation. The hydrogenated α-FeO can be easily recycled by magnets and has good photocatalytic stability. These findings offer possibilities for utilizing this inexpensive and earth-abundant oxide materials in the pollution controlling areas. [ABSTRACT FROM AUTHOR]