A Green, Low-Cost and Efficient Photocatalyst: Atomic-Hydrogenated α-Fe2O3

The environmental-friendly hematite iron oxide (α-Fe2O3) has important application prospects in the photocatalysis field owing to its narrow indirect band gap. Here, we report a band gap engineering of α-Fe2O3 by incorporation of electrochemically-generated atomic hydrogen at moderate conditions. The ultraviolet–visible spectra show the reduction of the α-Fe2O3 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-Fe2O3. Further photocatalytic degradation experiments of dyes demonstrate that the photocatalytic efficiency of α-Fe2O3 can be greatly enhanced by the atomic hydrogen incorporation. The hydrogenated α-Fe2O3 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.