Photocatalytic activity of a Bi-based oxychloride Bi4NbO8Cl

The Bi-based oxychloride Bi4NbO8Cl with a layered structure was studied as a novel efficient photocatalyst. The compound prepared by a solid state reaction method has a band gap of 2.38 eV. It possesses an excellent visible- light-response ability. The visible- light-driven photocatalytic activities for degrading methyl orange ( MO) over different catalysts follow the decreasing order of Bi4NbO8Cl > Bi3O4Cl > anatase TiO2, different from the order found under UV light illumination (Bi3O4Cl > anatase TiO2 > Bi4NbO8Cl). The dispersion of Pt over Bi4NbO8Cl leads to an obvious increase in photocatalytic performance, to about 1.5 times higher. The polarizing fields in NbO6 and BiO8 local structures, as well as the internal electrical fields between [Bi2O2] and [Cl] slabs, are considered to be useful for the efficient separation of electron hole pairs upon photoexcitation.