xBiOI–(1 − x)BiOCl as efficient visible-light-driven photocatalysts

A new class of oxyhalide photocatalysts, xBiOI–(1 − x)BiOCl, were prepared by a soft chemical method. The samples with x = 0.2–1.0 have intense absorptions in the visible light region and the optical band gaps are in the range 1.92–2.31 eV. They possess high photocatalytic activities under visible light irradiation for the degradation of methyl orange. This high photocatalytic activity is in close relation with the deep valance band edge position and the internal electric fields between [Bi2O2] slabs and halogen anionic slabs.